Unified Coverage Report :: Module :: prim_reg_cdc

Module : prim_reg_cdc

SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
96.43	100.00	85.71			100.00	100.00

Source File(s) :
/workspaces/repo/scratch/os_regression_2024_10_14/usbdev-sim-vcs/default/sim-vcs/../src/lowrisc_prim_subreg_0/rtl/prim_reg_cdc.sv

Module self-instances :

NAME	SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
tb.dut.u_reg.u_wake_events_cdc	78.29	94.12	85.71			83.33	50.00
tb.dut.u_reg.u_wake_control_cdc	97.73	100.00	90.91			100.00	100.00

---

Module Instance : tb.dut.u_reg.u_wake_events_cdc

Instance :

SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
78.29	94.12	85.71			83.33	50.00

Instance's subtree :

SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
74.50	90.62	63.16			84.21	60.00

Parent :

SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT	NAME
99.52	99.76	98.32			100.00	100.00	u_reg

Subtrees :

NAME	SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
u_arb	83.35	89.80	62.22			81.40	100.00
u_src_to_dst_req	58.08	92.31	40.00			100.00	0.00

---

Module Instance : tb.dut.u_reg.u_wake_control_cdc

Instance :

SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
97.73	100.00	90.91			100.00	100.00

Instance's subtree :

SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
98.13	96.08	96.43			100.00	100.00

Parent :

SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT	NAME
99.52	99.76	98.32			100.00	100.00	u_reg

Subtrees :

NAME	SCORE	LINE	COND	TOGGLE	FSM	BRANCH	ASSERT
u_arb	96.88	87.50	100.00			100.00	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.	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:       T7 T8 T9 
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:       T7 T8 T9 
75         1/1              end else if (src_ack) begin
           Tests:       T1 T2 T3 
76         1/1                src_busy_q <= 1'b0;
           Tests:       T7 T8 T9 
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:       T7 T8 T9 
124        1/1                txn_bits_q <= {src_we_i, src_re_i, src_regwen_i};
           Tests:       T7 T8 T9 
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:       T7 T8 T9 
135        1/1                txn_bits_q <= '0;
           Tests:       T7 T8 T9 
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

	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,T8,T9

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----

-1-	-2-	Status	Tests
0	1	Covered	T1,T2,T3
1	0	Covered	T7,T8,T9
1	1	Covered	T7,T8,T9

 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	T7,T8,T9
1	0	Covered	T7,T8,T9

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---

-1-	-2-	Status	Tests
0	1	Not Covered
1	0	Covered	T7,T8,T9
1	1	Covered	T7,T8,T9

 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	T7,T8,T9

---

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	T7,T8,T9
0	0	1	Covered	T7,T8,T9
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	T7,T8,T9
0	0	1	Covered	T7,T8,T9
0	0	0	Covered	T1,T2,T3

---

Assert Coverage for Module : prim_reg_cdc

	Total	Attempted	Percent	Succeeded/Matched	Percent
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

Name	Attempts	Real Successes	Failures	Incomplete
BusySrcReqChk_A	1160174066	279866	0	0
DstReqKnown_A	14242178	14174864	0	0
SrcAckBusyChk_A	1160174066	1152	0	0
SrcBusyKnown_A	1160174066	1159507928	0	0

BusySrcReqChk_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	1160174066	279866	0	0
T7	279126	287	0	0
T8	0	362	0	0
T9	0	383	0	0
T10	0	862	0	0
T11	0	304	0	0
T12	0	589	0	0
T13	0	326	0	0
T14	0	276	0	0
T15	0	423	0	0
T16	0	868	0	0
T17	9642	0	0	0
T18	23955	0	0	0
T19	44812	0	0	0
T20	27564	0	0	0
T21	10864	0	0	0
T22	1813	0	0	0
T23	12975	0	0	0
T24	11870	0	0	0
T25	8478	0	0	0

DstReqKnown_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	14242178	14174864	0	0
T1	136	120	0	0
T2	126	112	0	0
T3	168	150	0	0
T7	11430	11410	0	0
T17	76	58	0	0
T18	806	790	0	0
T19	528	514	0	0
T20	1078	1066	0	0
T21	72	58	0	0
T22	44	34	0	0

SrcAckBusyChk_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	1160174066	1152	0	0
T7	279126	2	0	0
T8	0	2	0	0
T9	0	2	0	0
T10	0	2	0	0
T11	0	2	0	0
T12	0	2	0	0
T13	0	2	0	0
T14	0	2	0	0
T15	0	2	0	0
T16	0	2	0	0
T17	9642	0	0	0
T18	23955	0	0	0
T19	44812	0	0	0
T20	27564	0	0	0
T21	10864	0	0	0
T22	1813	0	0	0
T23	12975	0	0	0
T24	11870	0	0	0
T25	8478	0	0	0

SrcBusyKnown_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	1160174066	1159507928	0	0
T1	19294	19114	0	0
T2	16294	16152	0	0
T3	14438	14312	0	0
T7	558252	558066	0	0
T17	19284	19152	0	0
T18	47910	47766	0	0
T19	89624	89462	0	0
T20	55128	54970	0	0
T21	21728	21610	0	0
T22	3626	3500	0	0

Line Coverage for Instance : tb.dut.u_reg.u_wake_events_cdc

	Line No.	Total	Covered	Percent
TOTAL		17	16	94.12
CONT_ASSIGN	65	0	0
ALWAYS	71	5	4	80.00
CONT_ASSIGN	85	1	1	100.00
CONT_ASSIGN	109	1	1	100.00
ALWAYS	115	7	7	100.00
CONT_ASSIGN	150	0	0
CONT_ASSIGN	155	1	1	100.00
CONT_ASSIGN	156	1	1	100.00
CONT_ASSIGN	200	1	1	100.00

64                      
65         unreachable    assign src_req = src_we_i | src_re_i;
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         unreachable        src_busy_q <= 1'b1;
75         1/1              end else if (src_ack) begin
           Tests:       T1 T2 T3 
76         0/1     ==>        src_busy_q <= 1'b0;
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        unreachable        src_q <= src_wd_i & BitMask;
124        unreachable        txn_bits_q <= {src_we_i, src_re_i, src_regwen_i};
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:       T7 T8 T9 
135        1/1                txn_bits_q <= '0;
           Tests:       T7 T8 T9 
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        unreachable    assign unused_wd = ^src_wd_i;
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_wake_events_cdc

	Total	Covered	Percent
Conditions	7	6	85.71
Logical	7	6	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	Unreachable

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----

-1-	-2-	Status	Tests	Exclude Annotation
0	1	Covered	T1,T2,T3
1	0	Excluded		VC_COV_UNR
1	1	Excluded		VC_COV_UNR

 LINE       125
 EXPRESSION ((src_busy_q && src_ack) || (src_update && ((!busy))))
             -----------1-----------    ------------2------------

-1-	-2-	Status	Tests	Exclude Annotation
0	0	Covered	T1,T2,T3
0	1	Covered	T7,T8,T9
1	0	Excluded		VC_COV_UNR

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---

-1-	-2-	Status	Tests	Exclude Annotation
0	1	Not Covered
1	0	Excluded		VC_COV_UNR
1	1	Excluded		VC_COV_UNR

 LINE       125
 SUB-EXPRESSION (src_update && ((!busy)))
                 -----1----    ----2----

-1-	-2-	Status	Tests	Exclude Annotation
0	1	Covered	T1,T2,T3
1	0	Excluded		VC_COV_UNR
1	1	Covered	T7,T8,T9

---

Branch Coverage for Instance : tb.dut.u_reg.u_wake_events_cdc

	Line No.	Total	Covered	Percent
Branches		6	5	83.33
IF	71	3	2	66.67
IF	115	3	3	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;
                 ==> (Unreachable)
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	-	Unreachable
0	0	1	Not Covered
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;
                 ==> (Unreachable)
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	-	Unreachable
0	0	1	Covered	T7,T8,T9
0	0	0	Covered	T1,T2,T3

---

Assert Coverage for Instance : tb.dut.u_reg.u_wake_events_cdc

	Total	Attempted	Percent	Succeeded/Matched	Percent
Assertions	4	4	100.00	2	50.00
Cover properties	0	0		0
Cover sequences	0	0		0
Total	4	4	100.00	2	50.00

---

Assertion Details

Name	Attempts	Real Successes	Failures	Incomplete
BusySrcReqChk_A	580087033	0	0	0
DstReqKnown_A	7121089	7087432	0	0
SrcAckBusyChk_A	580087033	0	0	0
SrcBusyKnown_A	580087033	579753964	0	0

BusySrcReqChk_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	580087033	0	0	0

DstReqKnown_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	7121089	7087432	0	0
T1	68	60	0	0
T2	63	56	0	0
T3	84	75	0	0
T7	5715	5705	0	0
T17	38	29	0	0
T18	403	395	0	0
T19	264	257	0	0
T20	539	533	0	0
T21	36	29	0	0
T22	22	17	0	0

SrcAckBusyChk_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	580087033	0	0	0

SrcBusyKnown_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	580087033	579753964	0	0
T1	9647	9557	0	0
T2	8147	8076	0	0
T3	7219	7156	0	0
T7	279126	279033	0	0
T17	9642	9576	0	0
T18	23955	23883	0	0
T19	44812	44731	0	0
T20	27564	27485	0	0
T21	10864	10805	0	0
T22	1813	1750	0	0

Line Coverage for Instance : tb.dut.u_reg.u_wake_control_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:       T7 T8 T9 
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:       T7 T8 T9 
75         1/1              end else if (src_ack) begin
           Tests:       T1 T2 T3 
76         1/1                src_busy_q <= 1'b0;
           Tests:       T7 T8 T9 
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:       T7 T8 T9 
124        1/1                txn_bits_q <= {src_we_i, src_re_i, src_regwen_i};
           Tests:       T7 T8 T9 
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:       T7 T8 T9 
135        1/1                txn_bits_q <= '0;
           Tests:       T7 T8 T9 
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_wake_control_cdc

	Total	Covered	Percent
Conditions	11	10	90.91
Logical	11	10	90.91
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,T8,T9

 LINE       109
 EXPRESSION (src_busy_q & ((!src_ack)))
             -----1----   ------2-----

-1-	-2-	Status	Tests
0	1	Covered	T1,T2,T3
1	0	Covered	T7,T8,T9
1	1	Covered	T7,T8,T9

 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	T7,T8,T9

 LINE       125
 SUB-EXPRESSION (src_busy_q && src_ack)
                 -----1----    ---2---

-1-	-2-	Status	Tests
0	1	Not Covered
1	0	Covered	T7,T8,T9
1	1	Covered	T7,T8,T9

 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 Instance : tb.dut.u_reg.u_wake_control_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	T7,T8,T9
0	0	1	Covered	T7,T8,T9
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	T7,T8,T9
0	0	1	Covered	T7,T8,T9
0	0	0	Covered	T1,T2,T3

---

Assert Coverage for Instance : tb.dut.u_reg.u_wake_control_cdc

	Total	Attempted	Percent	Succeeded/Matched	Percent
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

Name	Attempts	Real Successes	Failures	Incomplete
BusySrcReqChk_A	580087033	279866	0	0
DstReqKnown_A	7121089	7087432	0	0
SrcAckBusyChk_A	580087033	1152	0	0
SrcBusyKnown_A	580087033	579753964	0	0

BusySrcReqChk_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	580087033	279866	0	0
T7	279126	287	0	0
T8	0	362	0	0
T9	0	383	0	0
T10	0	862	0	0
T11	0	304	0	0
T12	0	589	0	0
T13	0	326	0	0
T14	0	276	0	0
T15	0	423	0	0
T16	0	868	0	0
T17	9642	0	0	0
T18	23955	0	0	0
T19	44812	0	0	0
T20	27564	0	0	0
T21	10864	0	0	0
T22	1813	0	0	0
T23	12975	0	0	0
T24	11870	0	0	0
T25	8478	0	0	0

DstReqKnown_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	7121089	7087432	0	0
T1	68	60	0	0
T2	63	56	0	0
T3	84	75	0	0
T7	5715	5705	0	0
T17	38	29	0	0
T18	403	395	0	0
T19	264	257	0	0
T20	539	533	0	0
T21	36	29	0	0
T22	22	17	0	0

SrcAckBusyChk_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	580087033	1152	0	0
T7	279126	2	0	0
T8	0	2	0	0
T9	0	2	0	0
T10	0	2	0	0
T11	0	2	0	0
T12	0	2	0	0
T13	0	2	0	0
T14	0	2	0	0
T15	0	2	0	0
T16	0	2	0	0
T17	9642	0	0	0
T18	23955	0	0	0
T19	44812	0	0	0
T20	27564	0	0	0
T21	10864	0	0	0
T22	1813	0	0	0
T23	12975	0	0	0
T24	11870	0	0	0
T25	8478	0	0	0

SrcBusyKnown_A

Name	Attempts	Real Successes	Failures	Incomplete
Total	580087033	579753964	0	0
T1	9647	9557	0	0
T2	8147	8076	0	0
T3	7219	7156	0	0
T7	279126	279033	0	0
T17	9642	9576	0	0
T18	23955	23883	0	0
T19	44812	44731	0	0
T20	27564	27485	0	0
T21	10864	10805	0	0
T22	1813	1750	0	0