Module Definition
dashboard | hierarchy | modlist | groups | tests | asserts



Module Instance : tb.dut.u_reg.u_wkup_count_hi_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
92.86 100.00 71.43 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
84.89 94.74 75.00 89.83 80.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 75.16 92.86 71.74 86.05 50.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wkup_ctrl_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
97.73 100.00 90.91 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
99.17 100.00 96.67 100.00 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 100.00 100.00 100.00 100.00 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wkup_thold_hi_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
97.73 100.00 90.91 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
99.17 100.00 96.67 100.00 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 100.00 100.00 100.00 100.00 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wkup_thold_lo_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
97.73 100.00 90.91 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
99.17 100.00 96.67 100.00 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 100.00 100.00 100.00 100.00 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wdog_ctrl_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
97.73 100.00 90.91 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
99.17 100.00 96.67 100.00 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 100.00 100.00 100.00 100.00 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wdog_bark_thold_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
97.73 100.00 90.91 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
99.17 100.00 96.67 100.00 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 100.00 100.00 100.00 100.00 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wdog_bite_thold_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
97.73 100.00 90.91 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
99.17 100.00 96.67 100.00 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 100.00 100.00 100.00 100.00 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wkup_count_lo_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
98.21 100.00 92.86 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
98.11 100.00 94.12 98.31 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 97.79 100.00 93.48 97.67 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wdog_count_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
98.21 100.00 92.86 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
98.11 100.00 94.12 98.31 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 97.79 100.00 93.48 97.67 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00



Module Instance : tb.dut.u_reg.u_wkup_cause_cdc

Instance :
SCORELINECONDTOGGLEFSMBRANCHASSERT
98.44 100.00 93.75 100.00 100.00


Instance's subtree :
SCORELINECONDTOGGLEFSMBRANCHASSERT
98.15 100.00 94.29 98.31 100.00


Parent :
SCORELINECONDTOGGLEFSMBRANCHASSERTNAME
100.00 100.00 100.00 100.00 100.00 u_reg


Subtrees :
NAMESCORELINECONDTOGGLEFSMBRANCHASSERT
u_arb 97.79 100.00 93.48 97.67 100.00
u_src_to_dst_req 100.00 100.00 100.00 100.00 100.00

Line Coverage for Module : prim_reg_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Module : prim_reg_cdc ( parameter DataWidth=13,ResetVal=0,BitMask=8191,DstWrReq=0,TxnWidth=3 + DataWidth=32,ResetVal=0,BitMask=-1,DstWrReq=0,TxnWidth=3 + DataWidth=32,ResetVal=0,BitMask=-1,DstWrReq=1,TxnWidth=3 + DataWidth=2,ResetVal=0,BitMask=3,DstWrReq=0,TxnWidth=3 )
Cond Coverage for Module self-instances :
SCORECOND
97.73 90.91
tb.dut.u_reg.u_wkup_ctrl_cdc

SCORECOND
97.73 90.91
tb.dut.u_reg.u_wkup_thold_hi_cdc

SCORECOND
97.73 90.91
tb.dut.u_reg.u_wkup_thold_lo_cdc

SCORECOND
97.73 90.91
tb.dut.u_reg.u_wdog_bark_thold_cdc

SCORECOND
97.73 90.91
tb.dut.u_reg.u_wdog_bite_thold_cdc

SCORECOND
92.86 71.43
tb.dut.u_reg.u_wkup_count_hi_cdc

SCORECOND
98.21 92.86
tb.dut.u_reg.u_wkup_count_lo_cdc

SCORECOND
98.21 92.86
tb.dut.u_reg.u_wdog_count_cdc

SCORECOND
97.73 90.91
tb.dut.u_reg.u_wdog_ctrl_cdc

TotalCoveredPercent
Conditions141392.86
Logical141392.86
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01CoveredT1,T2,T5
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT3,T4,T5
11CoveredT1,T2,T5

Cond Coverage for Module : prim_reg_cdc ( parameter DataWidth=1,ResetVal=0,BitMask=1,DstWrReq=1,TxnWidth=3 )
Cond Coverage for Module self-instances :
SCORECOND
98.44 93.75
tb.dut.u_reg.u_wkup_cause_cdc

TotalCoveredPercent
Conditions161593.75
Logical161593.75
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       123
 EXPRESSION (src_wd_i & BitMask)
             ----1---   ---2---
-1--2-StatusTests
0-CoveredT1,T2,T3
1-CoveredT34,T35,T36

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01CoveredT1,T2,T4
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT12,T32,T20
11CoveredT1,T2,T4

Branch Coverage for Module : prim_reg_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Module : prim_reg_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 2147483647 28903195 0 0
DstReqKnown_A 19458210 18558200 0 0
SrcAckBusyChk_A 2147483647 35735 0 0
SrcBusyKnown_A 2147483647 2147483647 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 2147483647 28903195 0 0
T1 103880 4709 0 0
T2 106110 6869 0 0
T3 138130 6985 0 0
T4 262360 27359 0 0
T5 358700 21737 0 0
T6 824490 9332 0 0
T7 80470 3611 0 0
T8 90050 3882 0 0
T9 49560 2063 0 0
T10 112180 8534 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 19458210 18558200 0 0
T1 850 260 0 0
T2 840 210 0 0
T3 1140 200 0 0
T4 720 180 0 0
T5 710 200 0 0
T6 4830 3880 0 0
T7 1230 310 0 0
T8 1270 270 0 0
T9 1090 310 0 0
T10 920 210 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 2147483647 35735 0 0
T1 103880 14 0 0
T2 106110 18 0 0
T3 138130 15 0 0
T4 262360 18 0 0
T5 358700 14 0 0
T6 824490 16 0 0
T7 80470 18 0 0
T8 90050 14 0 0
T9 49560 15 0 0
T10 112180 18 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 2147483647 2147483647 0 0
T1 103880 103310 0 0
T2 106110 105400 0 0
T3 138130 137250 0 0
T4 262360 261690 0 0
T5 358700 357760 0 0
T6 824490 823800 0 0
T7 80470 79740 0 0
T8 90050 89320 0 0
T9 49560 48650 0 0
T10 112180 111270 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wkup_count_hi_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wkup_count_hi_cdc
TotalCoveredPercent
Conditions141071.43
Logical141071.43
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01Not Covered
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10Not Covered
11Not Covered

Branch Coverage for Instance : tb.dut.u_reg.u_wkup_count_hi_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wkup_count_hi_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 3672368 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 4523 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 3672368 0 0
T1 10388 654 0 0
T2 10611 1172 0 0
T3 13813 884 0 0
T4 26236 4504 0 0
T5 35870 2904 0 0
T6 82449 1122 0 0
T7 8047 578 0 0
T8 9005 546 0 0
T9 4956 254 0 0
T10 11218 1421 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 4523 0 0
T1 10388 2 0 0
T2 10611 3 0 0
T3 13813 2 0 0
T4 26236 3 0 0
T5 35870 2 0 0
T6 82449 2 0 0
T7 8047 3 0 0
T8 9005 2 0 0
T9 4956 2 0 0
T10 11218 3 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wkup_ctrl_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wkup_ctrl_cdc
TotalCoveredPercent
Conditions111090.91
Logical111090.91
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10Unreachable
11Unreachable

Branch Coverage for Instance : tb.dut.u_reg.u_wkup_ctrl_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wkup_ctrl_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 3859108 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 4957 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 3859108 0 0
T1 10388 617 0 0
T2 10611 858 0 0
T3 13813 862 0 0
T4 26236 2462 0 0
T5 35870 2883 0 0
T6 82449 1617 0 0
T7 8047 424 0 0
T8 9005 542 0 0
T9 4956 250 0 0
T10 11218 958 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 4957 0 0
T1 10388 2 0 0
T2 10611 2 0 0
T3 13813 2 0 0
T4 26236 2 0 0
T5 35870 2 0 0
T6 82449 3 0 0
T7 8047 2 0 0
T8 9005 2 0 0
T9 4956 2 0 0
T10 11218 2 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wkup_thold_hi_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wkup_thold_hi_cdc
TotalCoveredPercent
Conditions111090.91
Logical111090.91
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10Unreachable
11Unreachable

Branch Coverage for Instance : tb.dut.u_reg.u_wkup_thold_hi_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wkup_thold_hi_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 2184108 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 2842 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2184108 0 0
T1 10388 307 0 0
T2 10611 324 0 0
T3 13813 428 0 0
T4 26236 1362 0 0
T5 35870 1440 0 0
T6 82449 635 0 0
T7 8047 151 0 0
T8 9005 271 0 0
T9 4956 125 0 0
T10 11218 471 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2842 0 0
T1 10388 1 0 0
T2 10611 1 0 0
T3 13813 1 0 0
T4 26236 1 0 0
T5 35870 1 0 0
T6 82449 1 0 0
T7 8047 1 0 0
T8 9005 1 0 0
T9 4956 1 0 0
T10 11218 1 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wkup_thold_lo_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wkup_thold_lo_cdc
TotalCoveredPercent
Conditions111090.91
Logical111090.91
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10Unreachable
11Unreachable

Branch Coverage for Instance : tb.dut.u_reg.u_wkup_thold_lo_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wkup_thold_lo_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 2161544 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 2827 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2161544 0 0
T1 10388 310 0 0
T2 10611 333 0 0
T3 13813 439 0 0
T4 26236 1371 0 0
T5 35870 1452 0 0
T6 82449 644 0 0
T7 8047 163 0 0
T8 9005 273 0 0
T9 4956 127 0 0
T10 11218 473 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2827 0 0
T1 10388 1 0 0
T2 10611 1 0 0
T3 13813 1 0 0
T4 26236 1 0 0
T5 35870 1 0 0
T6 82449 1 0 0
T7 8047 1 0 0
T8 9005 1 0 0
T9 4956 1 0 0
T10 11218 1 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wdog_ctrl_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wdog_ctrl_cdc
TotalCoveredPercent
Conditions111090.91
Logical111090.91
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10Unreachable
11Unreachable

Branch Coverage for Instance : tb.dut.u_reg.u_wdog_ctrl_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wdog_ctrl_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 3097029 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 3890 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 3097029 0 0
T1 10388 342 0 0
T2 10611 863 0 0
T3 13813 849 0 0
T4 26236 2459 0 0
T5 35870 1461 0 0
T6 82449 1158 0 0
T7 8047 428 0 0
T8 9005 277 0 0
T9 4956 246 0 0
T10 11218 958 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 3890 0 0
T1 10388 1 0 0
T2 10611 2 0 0
T3 13813 2 0 0
T4 26236 2 0 0
T5 35870 1 0 0
T6 82449 2 0 0
T7 8047 2 0 0
T8 9005 1 0 0
T9 4956 2 0 0
T10 11218 2 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wdog_bark_thold_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wdog_bark_thold_cdc
TotalCoveredPercent
Conditions111090.91
Logical111090.91
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10Unreachable
11Unreachable

Branch Coverage for Instance : tb.dut.u_reg.u_wdog_bark_thold_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wdog_bark_thold_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 2147465 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 2833 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2147465 0 0
T1 10388 305 0 0
T2 10611 313 0 0
T3 13813 419 0 0
T4 26236 1354 0 0
T5 35870 1434 0 0
T6 82449 630 0 0
T7 8047 147 0 0
T8 9005 269 0 0
T9 4956 123 0 0
T10 11218 469 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2833 0 0
T1 10388 1 0 0
T2 10611 1 0 0
T3 13813 1 0 0
T4 26236 1 0 0
T5 35870 1 0 0
T6 82449 1 0 0
T7 8047 1 0 0
T8 9005 1 0 0
T9 4956 1 0 0
T10 11218 1 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wdog_bite_thold_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wdog_bite_thold_cdc
TotalCoveredPercent
Conditions111090.91
Logical111090.91
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10Unreachable
11Unreachable

Branch Coverage for Instance : tb.dut.u_reg.u_wdog_bite_thold_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wdog_bite_thold_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 2106490 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 2777 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2106490 0 0
T1 10388 295 0 0
T2 10611 307 0 0
T3 13813 407 0 0
T4 26236 1340 0 0
T5 35870 1431 0 0
T6 82449 628 0 0
T7 8047 142 0 0
T8 9005 267 0 0
T9 4956 121 0 0
T10 11218 467 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2777 0 0
T1 10388 1 0 0
T2 10611 1 0 0
T3 13813 1 0 0
T4 26236 1 0 0
T5 35870 1 0 0
T6 82449 1 0 0
T7 8047 1 0 0
T8 9005 1 0 0
T9 4956 1 0 0
T10 11218 1 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wkup_count_lo_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wkup_count_lo_cdc
TotalCoveredPercent
Conditions141392.86
Logical141392.86
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01CoveredT1,T2,T5
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT3,T4,T5
11CoveredT1,T2,T5

Branch Coverage for Instance : tb.dut.u_reg.u_wkup_count_lo_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wkup_count_lo_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 4082773 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 4507 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 4082773 0 0
T1 10388 908 0 0
T2 10611 1192 0 0
T3 13813 1135 0 0
T4 26236 5605 0 0
T5 35870 4397 0 0
T6 82449 1139 0 0
T7 8047 851 0 0
T8 9005 620 0 0
T9 4956 348 0 0
T10 11218 1427 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 4507 0 0
T1 10388 2 0 0
T2 10611 3 0 0
T3 13813 2 0 0
T4 26236 3 0 0
T5 35870 2 0 0
T6 82449 2 0 0
T7 8047 3 0 0
T8 9005 2 0 0
T9 4956 2 0 0
T10 11218 3 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wdog_count_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wdog_count_cdc
TotalCoveredPercent
Conditions141392.86
Logical141392.86
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01CoveredT2,T9,T10
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT3,T4,T11
11CoveredT2,T9,T10

Branch Coverage for Instance : tb.dut.u_reg.u_wdog_count_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wdog_count_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 3814137 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 4517 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 3814137 0 0
T1 10388 631 0 0
T2 10611 1150 0 0
T3 13813 1106 0 0
T4 26236 5520 0 0
T5 35870 2886 0 0
T6 82449 1106 0 0
T7 8047 562 0 0
T8 9005 542 0 0
T9 4956 340 0 0
T10 11218 1415 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 4517 0 0
T1 10388 2 0 0
T2 10611 3 0 0
T3 13813 2 0 0
T4 26236 3 0 0
T5 35870 2 0 0
T6 82449 2 0 0
T7 8047 3 0 0
T8 9005 2 0 0
T9 4956 2 0 0
T10 11218 3 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

Line Coverage for Instance : tb.dut.u_reg.u_wkup_cause_cdc
Line No.TotalCoveredPercent
TOTAL2222100.00
CONT_ASSIGN6511100.00
ALWAYS7166100.00
CONT_ASSIGN8511100.00
CONT_ASSIGN10911100.00
ALWAYS11599100.00
CONT_ASSIGN15011100.00
CONT_ASSIGN15511100.00
CONT_ASSIGN15611100.00
CONT_ASSIGN20011100.00

64 65 1/1 assign src_req = src_we_i | src_re_i; Tests: T1 T2 T3  66 67 // busy indication back-pressures upstream if the register is accessed 68 // again. The busy indication is also used as a "commit" indication for 69 // resolving software and hardware write conflicts 70 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 71 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  72 1/1 src_busy_q <= '0; Tests: T1 T2 T3  73 1/1 end else if (src_req) begin Tests: T1 T2 T3  74 1/1 src_busy_q <= 1'b1; Tests: T1 T2 T3  75 1/1 end else if (src_ack) begin Tests: T1 T2 T3  76 1/1 src_busy_q <= 1'b0; Tests: T1 T2 T3  77 end MISSING_ELSE 78 end 79 80 // A src_ack should only be sent if there was a src_req. 81 // src_busy_q asserts whenever there is a src_req. By association, 82 // whenever src_ack is seen, then src_busy must be high. 83 `ASSERT(SrcAckBusyChk_A, src_ack |-> src_busy_q, clk_src_i, !rst_src_ni) 84 85 1/1 assign src_busy_o = src_busy_q; Tests: T1 T2 T3  86 87 // src_q acts as both the write holding register and the software read back 88 // register. 89 // When software performs a write, the write data is captured in src_q for 90 // CDC purposes. When not performing a write, the src_q reflects the most recent 91 // hardware value. For registers with no hardware access, this is simply the 92 // the value programmed by software (or in the case R1C, W1C etc) the value after 93 // the operation. For registers with hardware access, this reflects a potentially 94 // delayed version of the real value, as the software facing updates lag real 95 // time updates. 96 // 97 // To resolve software and hardware conflicts, the process is as follows: 98 // When software issues a write, this module asserts "busy". While busy, 99 // src_q does not take on destination value updates. Since the 100 // logic has committed to updating based on software command, there is an irreversible 101 // window from which hardware writes are ignored. Once the busy window completes, 102 // the cdc portion then begins sampling once more. 103 // 104 // This is consistent with prim_subreg_arb where during software / hardware conflicts, 105 // software is always prioritized. The main difference is the conflict resolution window 106 // is now larger instead of just one destination clock cycle. 107 108 logic busy; 109 1/1 assign busy = src_busy_q & !src_ack; Tests: T1 T2 T3  110 111 // This is the current destination value 112 logic [DataWidth-1:0] dst_qs; 113 logic src_update; 114 always_ff @(posedge clk_src_i or negedge rst_src_ni) begin 115 1/1 if (!rst_src_ni) begin Tests: T1 T2 T3  116 1/1 src_q <= ResetVal; Tests: T1 T2 T3  117 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  118 1/1 end else if (src_req) begin Tests: T1 T2 T3  119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 1/1 src_q <= src_wd_i & BitMask; Tests: T1 T2 T3  124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; Tests: T1 T2 T3  125 1/1 end else if (src_busy_q && src_ack || src_update && !busy) begin Tests: T1 T2 T3  126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 1/1 src_q <= dst_qs; Tests: T1 T2 T3  135 1/1 txn_bits_q <= '0; Tests: T1 T2 T3  136 end MISSING_ELSE 137 end 138 139 // The current design (tlul_adapter_reg) does not spit out a request if the destination it chooses 140 // (decoded from address) is busy. So this creates a situation in the current design where 141 // src_req_i and busy can never be high at the same time. 142 // While the code above could be coded directly to be expressed as `src_req & !busy`, which makes 143 // the intent clearer, it ends up causing coverage holes from the tool's perspective since that 144 // condition cannot be met. 145 // Thus we add an assertion here to ensure the condition is always satisfied. 146 `ASSERT(BusySrcReqChk_A, busy |-> !src_req, clk_src_i, !rst_src_ni) 147 148 // reserved bits are not used 149 logic unused_wd; 150 1/1 assign unused_wd = ^src_wd_i; Tests: T1 T2 T3  151 152 // src_q is always updated in the clk_src domain. 153 // when performing an update to the destination domain, it is guaranteed 154 // to not change by protocol. 155 1/1 assign src_qs_o = src_q; Tests: T1 T2 T3  156 1/1 assign dst_wd_o = src_q; Tests: T1 T2 T3  157 158 //////////////////////////// 159 // CDC handling 160 //////////////////////////// 161 162 logic dst_req_from_src; 163 logic dst_req; 164 165 166 // the software transaction is pulse synced across the domain. 167 // the prim_reg_cdc_arb module handles conflicts with ongoing hardware updates. 168 prim_pulse_sync u_src_to_dst_req ( 169 .clk_src_i, 170 .rst_src_ni, 171 .clk_dst_i, 172 .rst_dst_ni, 173 .src_pulse_i(src_req), 174 .dst_pulse_o(dst_req_from_src) 175 ); 176 177 prim_reg_cdc_arb #( 178 .DataWidth(DataWidth), 179 .ResetVal(ResetVal), 180 .DstWrReq(DstWrReq) 181 ) u_arb ( 182 .clk_src_i, 183 .rst_src_ni, 184 .clk_dst_i, 185 .rst_dst_ni, 186 .src_ack_o(src_ack), 187 .src_update_o(src_update), 188 .dst_req_i(dst_req_from_src), 189 .dst_req_o(dst_req), 190 .dst_update_i, 191 .dst_ds_i, 192 .dst_qs_i, 193 .dst_qs_o(dst_qs) 194 ); 195 196 197 // Each is valid only when destination request pulse is high; this is important in not propagating 198 // the internal assertion of 'dst_req' by the 'prim_pulse_sync' channel when just one domain is 199 // reset. 200 1/1 assign {dst_we_o, dst_re_o, dst_regwen_o} = txn_bits_q & {TxnWidth{dst_req}}; Tests: T1 T2 T3 

Cond Coverage for Instance : tb.dut.u_reg.u_wkup_cause_cdc
TotalCoveredPercent
Conditions161593.75
Logical161593.75
Non-Logical00
Event00

 LINE       65
 EXPRESSION (src_we_i | src_re_i)
             ----1---   ----2---
-1--2-StatusTests
00CoveredT1,T2,T3
01Unreachable
10CoveredT1,T2,T3

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       123
 EXPRESSION (src_wd_i & BitMask)
             ----1---   ---2---
-1--2-StatusTests
0-CoveredT1,T2,T3
1-CoveredT34,T35,T36

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------
-1--2-StatusTests
00CoveredT1,T2,T3
01CoveredT1,T2,T4
10CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---
-1--2-StatusTests
01Not Covered
10CoveredT1,T2,T3
11CoveredT1,T2,T3

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----
-1--2-StatusTests
01CoveredT1,T2,T3
10CoveredT12,T32,T20
11CoveredT1,T2,T4

Branch Coverage for Instance : tb.dut.u_reg.u_wkup_cause_cdc
Line No.TotalCoveredPercent
Branches 8 8 100.00
IF 71 4 4 100.00
IF 115 4 4 100.00


71 if (!rst_src_ni) begin -1- 72 src_busy_q <= '0; ==> 73 end else if (src_req) begin -2- 74 src_busy_q <= 1'b1; ==> 75 end else if (src_ack) begin -3- 76 src_busy_q <= 1'b0; ==> 77 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


115 if (!rst_src_ni) begin -1- 116 src_q <= ResetVal; ==> 117 txn_bits_q <= '0; 118 end else if (src_req) begin -2- 119 // See assertion below 120 // At the beginning of a software initiated transaction, the following 121 // values are captured in the src_q/txn_bits_q flops to ensure they cannot 122 // change for the duration of the synchronization operation. 123 src_q <= src_wd_i & BitMask; ==> 124 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i}; 125 end else if (src_busy_q && src_ack || src_update && !busy) begin -3- 126 // sample data whenever a busy transaction finishes OR 127 // when an update pulse is seen. 128 // TODO: We should add a cover group to test different sync timings 129 // between src_ack and src_update. ie. there can be 3 scenarios: 130 // 1. update one cycle before ack 131 // 2. ack one cycle before update 132 // 3. update / ack on the same cycle 133 // During all 3 cases the read data should be correct 134 src_q <= dst_qs; ==> 135 txn_bits_q <= '0; 136 end MISSING_ELSE ==>

Branches:
-1--2--3-StatusTests
1 - - Covered T1,T2,T3
0 1 - Covered T1,T2,T3
0 0 1 Covered T1,T2,T3
0 0 0 Covered T1,T2,T3


Assert Coverage for Instance : tb.dut.u_reg.u_wkup_cause_cdc
TotalAttemptedPercentSucceeded/MatchedPercent
Assertions 4 4 100.00 4 100.00
Cover properties 0 0 0
Cover sequences 0 0 0
Total 4 4 100.00 4 100.00




Assertion Details

NameAttemptsReal SuccessesFailuresIncomplete
BusySrcReqChk_A 468181247 1778173 0 0
DstReqKnown_A 1945821 1855820 0 0
SrcAckBusyChk_A 468181247 2062 0 0
SrcBusyKnown_A 468181247 467995924 0 0


BusySrcReqChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 1778173 0 0
T1 10388 340 0 0
T2 10611 357 0 0
T3 13813 456 0 0
T4 26236 1382 0 0
T5 35870 1449 0 0
T6 82449 653 0 0
T7 8047 165 0 0
T8 9005 275 0 0
T9 4956 129 0 0
T10 11218 475 0 0

DstReqKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 1945821 1855820 0 0
T1 85 26 0 0
T2 84 21 0 0
T3 114 20 0 0
T4 72 18 0 0
T5 71 20 0 0
T6 483 388 0 0
T7 123 31 0 0
T8 127 27 0 0
T9 109 31 0 0
T10 92 21 0 0

SrcAckBusyChk_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 2062 0 0
T1 10388 1 0 0
T2 10611 1 0 0
T3 13813 1 0 0
T4 26236 1 0 0
T5 35870 1 0 0
T6 82449 1 0 0
T7 8047 1 0 0
T8 9005 1 0 0
T9 4956 1 0 0
T10 11218 1 0 0

SrcBusyKnown_A
NameAttemptsReal SuccessesFailuresIncomplete
Total 468181247 467995924 0 0
T1 10388 10331 0 0
T2 10611 10540 0 0
T3 13813 13725 0 0
T4 26236 26169 0 0
T5 35870 35776 0 0
T6 82449 82380 0 0
T7 8047 7974 0 0
T8 9005 8932 0 0
T9 4956 4865 0 0
T10 11218 11127 0 0

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%