Line Coverage for Module :
prim_reg_cdc
| Line No. | Total | Covered | Percent |
TOTAL | | 22 | 22 | 100.00 |
CONT_ASSIGN | 65 | 1 | 1 | 100.00 |
ALWAYS | 71 | 6 | 6 | 100.00 |
CONT_ASSIGN | 85 | 1 | 1 | 100.00 |
CONT_ASSIGN | 109 | 1 | 1 | 100.00 |
ALWAYS | 115 | 9 | 9 | 100.00 |
CONT_ASSIGN | 150 | 1 | 1 | 100.00 |
CONT_ASSIGN | 155 | 1 | 1 | 100.00 |
CONT_ASSIGN | 156 | 1 | 1 | 100.00 |
CONT_ASSIGN | 200 | 1 | 1 | 100.00 |
64
65 1/1 assign src_req = src_we_i | src_re_i;
Tests: T27 T7 T16
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: T27 T7 T16
75 1/1 end else if (src_ack) begin
Tests: T1 T2 T3
76 1/1 src_busy_q <= 1'b0;
Tests: T27 T7 T16
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: T27 T7 T16
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: T27 T7 T16
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: T27 T7 T16
124 1/1 txn_bits_q <= {src_we_i, src_re_i, src_regwen_i};
Tests: T27 T7 T16
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: T27 T7 T16
135 1/1 txn_bits_q <= '0;
Tests: T27 T7 T16
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: T27 T7 T16
156 1/1 assign dst_wd_o = src_q;
Tests: T27 T7 T16
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: T27 T7 T16
Cond Coverage for Module :
prim_reg_cdc ( parameter DataWidth=2,ResetVal=0,BitMask=3,DstWrReq=0,TxnWidth=3 + DataWidth=11,ResetVal=0,BitMask=1793,DstWrReq=1,TxnWidth=3 + DataWidth=4,ResetVal=9,BitMask=15,DstWrReq=1,TxnWidth=3 + DataWidth=20,ResetVal,BitMask=1048575,DstWrReq=0,TxnWidth=3 + DataWidth=18,ResetVal=118010,BitMask=262143,DstWrReq=0,TxnWidth=3 + DataWidth=16,ResetVal,BitMask=65535,DstWrReq=0,TxnWidth=3 + DataWidth=12,ResetVal=0,BitMask=4095,DstWrReq=0,TxnWidth=3 + DataWidth=8,ResetVal,BitMask=255,DstWrReq=0,TxnWidth=3 + DataWidth=14,ResetVal=0,BitMask=16383,DstWrReq=0,TxnWidth=3 + DataWidth=17,ResetVal=2000,BitMask=131071,DstWrReq=0,TxnWidth=3 + DataWidth=7,ResetVal=0,BitMask=119,DstWrReq=0,TxnWidth=3 + DataWidth=5,ResetVal=0,BitMask=31,DstWrReq=0,TxnWidth=3 + DataWidth=32,ResetVal,BitMask,DstWrReq=0,TxnWidth=3 + DataWidth=4,ResetVal=0,BitMask=15,DstWrReq=0,TxnWidth=3 + DataWidth=28,ResetVal=0,BitMask=268374015,DstWrReq=1,TxnWidth=3 + DataWidth=9,ResetVal=0,BitMask=511,DstWrReq=0,TxnWidth=3 + DataWidth=9,ResetVal=0,BitMask=511,DstWrReq=1,TxnWidth=3 + DataWidth=5,ResetVal=0,BitMask=31,DstWrReq=1,TxnWidth=3 + DataWidth=6,ResetVal=0,BitMask=63,DstWrReq=0,TxnWidth=3 + DataWidth=8,ResetVal=0,BitMask=255,DstWrReq=1,TxnWidth=3 + DataWidth=13,ResetVal=0,BitMask=8191,DstWrReq=0,TxnWidth=3 + DataWidth=32,ResetVal=0,BitMask=-1,DstWrReq=1,TxnWidth=3 )
Cond Coverage for Module self-instances :
| Total | Covered | Percent |
Conditions | 14 | 12 | 85.71 |
Logical | 14 | 12 | 85.71 |
Non-Logical | 0 | 0 | |
Event | 0 | 0 | |
LINE 65
EXPRESSION (src_we_i | src_re_i)
----1--- ----2---
-1- | -2- | Status | Tests |
0 | 0 | Covered | T1,T2,T3 |
0 | 1 | Unreachable | |
1 | 0 | Covered | T7,T16,T63 |
LINE 109
EXPRESSION (src_busy_q & ((!src_ack)))
-----1---- ------2-----
-1- | -2- | Status | Tests |
0 | 1 | Covered | T1,T2,T3 |
1 | 0 | Covered | T27,T7,T16 |
1 | 1 | Covered | T27,T7,T16 |
LINE 125
EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
-----------1----------- ------------2------------
-1- | -2- | Status | Tests |
0 | 0 | Covered | T1,T2,T3 |
0 | 1 | Covered | T27,T7,T16 |
1 | 0 | Covered | T27,T7,T16 |
LINE 125
SUB-EXPRESSION (src_busy_q && src_ack)
-----1---- ---2---
-1- | -2- | Status | Tests |
0 | 1 | Not Covered | |
1 | 0 | Covered | T27,T7,T16 |
1 | 1 | Covered | T27,T7,T16 |
LINE 125
SUB-EXPRESSION (src_update && ((!busy)))
-----1---- ----2----
-1- | -2- | Status | Tests |
0 | 1 | Covered | T1,T2,T3 |
1 | 0 | Not Covered | |
1 | 1 | Covered | T27,T7,T16 |
Cond Coverage for Module :
prim_reg_cdc ( parameter DataWidth=1,ResetVal=0,BitMask=1,DstWrReq=0,TxnWidth=3 + DataWidth=1,ResetVal=0,BitMask=1,DstWrReq=1,TxnWidth=3 )
Cond Coverage for Module self-instances :
| Total | Covered | Percent |
Conditions | 13 | 12 | 92.31 |
Logical | 13 | 12 | 92.31 |
Non-Logical | 0 | 0 | |
Event | 0 | 0 | |
LINE 65
EXPRESSION (src_we_i | src_re_i)
----1--- ----2---
-1- | -2- | Status | Tests |
0 | 0 | Covered | T1,T2,T3 |
0 | 1 | Unreachable | |
1 | 0 | Covered | T27,T7,T16 |
LINE 109
EXPRESSION (src_busy_q & ((!src_ack)))
-----1---- ------2-----
-1- | -2- | Status | Tests |
0 | 1 | Covered | T1,T2,T3 |
1 | 0 | Covered | T27,T7,T16 |
1 | 1 | Covered | T27,T7,T16 |
LINE 123
EXPRESSION (src_wd_i & BitMask)
----1--- ---2---
-1- | -2- | Status | Tests |
0 | - | Covered | T27,T7,T16 |
1 | - | Covered | T27,T7,T16 |
LINE 125
EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
-----------1----------- ------------2------------
-1- | -2- | Status | Tests |
0 | 0 | Covered | T1,T2,T3 |
0 | 1 | Unreachable | |
1 | 0 | Covered | T27,T7,T16 |
LINE 125
SUB-EXPRESSION (src_busy_q && src_ack)
-----1---- ---2---
-1- | -2- | Status | Tests |
0 | 1 | Not Covered | |
1 | 0 | Covered | T27,T7,T16 |
1 | 1 | Covered | T27,T7,T16 |
LINE 125
SUB-EXPRESSION (src_update && ((!busy)))
-----1---- ----2----
-1- | -2- | Status | Tests |
0 | 1 | Covered | T1,T2,T3 |
1 | 0 | Unreachable | |
1 | 1 | Unreachable | |
Branch Coverage for Module :
prim_reg_cdc
| Line No. | Total | Covered | Percent |
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- | Status | Tests |
1 |
- |
- |
Covered |
T1,T2,T3 |
0 |
1 |
- |
Covered |
T27,T7,T16 |
0 |
0 |
1 |
Covered |
T27,T7,T16 |
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- | Status | Tests |
1 |
- |
- |
Covered |
T1,T2,T3 |
0 |
1 |
- |
Covered |
T27,T7,T16 |
0 |
0 |
1 |
Covered |
T27,T7,T16 |
0 |
0 |
0 |
Covered |
T1,T2,T3 |
Assert Coverage for Module :
prim_reg_cdc
Assertion Details
BusySrcReqChk_A
Name | Attempts | Real Successes | Failures | Incomplete |
Total |
2147483647 |
3201910 |
0 |
0 |
T7 |
132909 |
2315 |
0 |
0 |
T11 |
133218 |
0 |
0 |
0 |
T12 |
43764 |
0 |
0 |
0 |
T15 |
112109 |
0 |
0 |
0 |
T16 |
63214 |
1948 |
0 |
0 |
T27 |
38517 |
395 |
0 |
0 |
T31 |
156204 |
0 |
0 |
0 |
T32 |
166977 |
0 |
0 |
0 |
T48 |
186873 |
0 |
0 |
0 |
T49 |
174093 |
0 |
0 |
0 |
T50 |
195693 |
0 |
0 |
0 |
T60 |
226438 |
0 |
0 |
0 |
T61 |
228797 |
0 |
0 |
0 |
T64 |
441753 |
1249 |
0 |
0 |
T65 |
0 |
1795 |
0 |
0 |
T66 |
0 |
1709 |
0 |
0 |
T67 |
0 |
725 |
0 |
0 |
T68 |
0 |
797 |
0 |
0 |
T69 |
0 |
1352 |
0 |
0 |
T70 |
0 |
876 |
0 |
0 |
T71 |
0 |
1582 |
0 |
0 |
T72 |
0 |
357 |
0 |
0 |
T100 |
368407 |
0 |
0 |
0 |
T101 |
713039 |
0 |
0 |
0 |
T125 |
0 |
786 |
0 |
0 |
T126 |
175671 |
0 |
0 |
0 |
T141 |
348683 |
0 |
0 |
0 |
T183 |
0 |
1339 |
0 |
0 |
T184 |
0 |
521 |
0 |
0 |
T274 |
574020 |
0 |
0 |
0 |
T321 |
272482 |
0 |
0 |
0 |
T404 |
0 |
4860 |
0 |
0 |
T408 |
0 |
1264 |
0 |
0 |
T409 |
0 |
1194 |
0 |
0 |
T424 |
0 |
1472 |
0 |
0 |
T433 |
0 |
838 |
0 |
0 |
T434 |
0 |
340 |
0 |
0 |
T435 |
90874 |
0 |
0 |
0 |
DstReqKnown_A
Name | Attempts | Real Successes | Failures | Incomplete |
Total |
48699350 |
43026850 |
0 |
0 |
T1 |
7050 |
2700 |
0 |
0 |
T2 |
8325 |
3975 |
0 |
0 |
T3 |
8575 |
4225 |
0 |
0 |
T4 |
11825 |
7500 |
0 |
0 |
T5 |
12750 |
8450 |
0 |
0 |
T6 |
9625 |
5275 |
0 |
0 |
T8 |
12725 |
8400 |
0 |
0 |
T9 |
8775 |
4425 |
0 |
0 |
T27 |
21475 |
17150 |
0 |
0 |
T38 |
8100 |
3775 |
0 |
0 |
SrcAckBusyChk_A
Name | Attempts | Real Successes | Failures | Incomplete |
Total |
2147483647 |
7959 |
0 |
0 |
T7 |
132909 |
5 |
0 |
0 |
T11 |
133218 |
0 |
0 |
0 |
T12 |
43764 |
0 |
0 |
0 |
T15 |
112109 |
0 |
0 |
0 |
T16 |
63214 |
5 |
0 |
0 |
T27 |
38517 |
1 |
0 |
0 |
T31 |
156204 |
0 |
0 |
0 |
T32 |
166977 |
0 |
0 |
0 |
T48 |
186873 |
0 |
0 |
0 |
T49 |
174093 |
0 |
0 |
0 |
T50 |
195693 |
0 |
0 |
0 |
T60 |
226438 |
0 |
0 |
0 |
T61 |
228797 |
0 |
0 |
0 |
T64 |
441753 |
4 |
0 |
0 |
T65 |
0 |
4 |
0 |
0 |
T66 |
0 |
5 |
0 |
0 |
T67 |
0 |
2 |
0 |
0 |
T68 |
0 |
2 |
0 |
0 |
T69 |
0 |
4 |
0 |
0 |
T70 |
0 |
2 |
0 |
0 |
T71 |
0 |
5 |
0 |
0 |
T72 |
0 |
1 |
0 |
0 |
T100 |
368407 |
0 |
0 |
0 |
T101 |
713039 |
0 |
0 |
0 |
T125 |
0 |
2 |
0 |
0 |
T126 |
175671 |
0 |
0 |
0 |
T141 |
348683 |
0 |
0 |
0 |
T183 |
0 |
4 |
0 |
0 |
T184 |
0 |
2 |
0 |
0 |
T274 |
574020 |
0 |
0 |
0 |
T321 |
272482 |
0 |
0 |
0 |
T404 |
0 |
12 |
0 |
0 |
T408 |
0 |
3 |
0 |
0 |
T409 |
0 |
3 |
0 |
0 |
T424 |
0 |
4 |
0 |
0 |
T433 |
0 |
2 |
0 |
0 |
T434 |
0 |
1 |
0 |
0 |
T435 |
90874 |
0 |
0 |
0 |
SrcBusyKnown_A
Name | Attempts | Real Successes | Failures | Incomplete |
Total |
2147483647 |
2147483647 |
0 |
0 |
T1 |
280925 |
262850 |
0 |
0 |
T2 |
391750 |
376050 |
0 |
0 |
T3 |
416025 |
400250 |
0 |
0 |
T4 |
569100 |
560875 |
0 |
0 |
T5 |
713950 |
704175 |
0 |
0 |
T6 |
661250 |
638350 |
0 |
0 |
T8 |
661725 |
653350 |
0 |
0 |
T9 |
574725 |
550400 |
0 |
0 |
T27 |
962925 |
944625 |
0 |
0 |
T38 |
390900 |
376100 |
0 |
0 |