Commit Graph

90 Commits

Author SHA1 Message Date
Ross Thompson
511c36fb1b Improved address bus names and usages in the walker, dcache, and tlbs.
Merge branch 'walkerEnhance' into main
2021-07-21 14:55:09 -05:00
Ross Thompson
abe57e3fd0 Added comment about better muxing. 2021-07-21 14:40:14 -05:00
Ross Thompson
3d79dc51bb 4 way set associative is now working. 2021-07-21 14:01:14 -05:00
Ross Thompson
39fc9278ba Fixed remaining bugs in 2 way set associative dcache. 2021-07-21 10:35:23 -05:00
Ross Thompson
ba3aed8760 Finally fixed bug with the set associative design. The issue was not in the LRU but instead in the way selection mux.
Also forgot to include cacheLRU.sv file.
2021-07-20 23:17:42 -05:00
Ross Thompson
8d0a552b5b Partially working 2 way set associative d cache. 2021-07-20 17:51:42 -05:00
Ross Thompson
bb5b5e71b1 Replaced FinalReadDataM with ReadDataM in dcache. 2021-07-20 13:27:29 -05:00
David Harris
c117356432 Parameterized I$/D$ configurations and added sanity check assertions in testbench 2021-07-20 08:57:13 -04:00
Ross Thompson
ae2371f2ce Added performance counters for dcache access and dcache miss. 2021-07-19 22:12:20 -05:00
Ross Thompson
5edd513f8c Furture simplification of the dcache ReadDataW update. 2021-07-19 12:46:31 -05:00
Ross Thompson
2ee97efb9c Fixed a complex bug in the dcache, where back to back loads would lose data on the load before a stall occurred. The solution was to modify the logic for SelAdrM in the dcache so that a stall would cause the SRAM to reread the address in the Memory stage rather than Execution stage. This also required updating the ReadDataWEn control so it is always enabled on ~StallW. 2021-07-19 12:32:16 -05:00
Ross Thompson
6ccbdc372d Broken.
Possible change to walker, dcache, tlb addressing.
Improves the naming of address signals.
But has a problem when the walker finishes the dcache does not get the correct
address on the cycle the DTLB is updated.  This leads to incorrect index
selection in the dcache.
2021-07-19 10:33:27 -05:00
bbracker
986b7a8252 change sram1rw to have a small delay so that we don't have signals changing on clock edges 2021-07-19 11:30:07 -04:00
Ross Thompson
d0ed6e250a Fixed LRSC in 64bit version. 32bit version is broken. 2021-07-17 20:58:49 -05:00
Ross Thompson
053e9593af Before returning to the ready state the dcache must set SelAdr = 0 on the cycle before. 2021-07-17 18:26:29 -05:00
Ross Thompson
e9649eb1f5 Made furture progress in the mmu tests. 2021-07-16 15:56:06 -05:00
Ross Thompson
abce241f68 Also changed the shadow ram's dcache copy widths.
Merge branch 'dcache' into main
2021-07-16 14:21:09 -05:00
Ross Thompson
d3715acf2d Fixed walker fault interaction with dcache. 2021-07-16 12:22:13 -05:00
Ross Thompson
5ca7dc619c Updated the ptw, lsuarb and dcache to hopefully solve the interlock issues. 2021-07-16 11:12:57 -05:00
Kip Macsai-Goren
ba5bb12e26 Still broken, midway through fixing understanding of how ptw and datacache interact in time especially wrt adrE, adrM, faults, and tlb interaction. 2021-07-15 18:30:29 -04:00
Ross Thompson
c39a228266 Fixed how the dcache and page table walker stall cpu so that once a tlb miss occurs the CPU is always stalled until the walk is complete, the tlb updated, and the dcache fetched and hits. 2021-07-15 11:00:42 -05:00
Ross Thompson
c954fb510b Renamed DCacheStall to LSUStall in hart and hazard.
Added missing logic in lsu.
2021-07-15 10:16:16 -05:00
Ross Thompson
f234875779 dcache STATE_CPU_BUSY needs to assert CommittedM. This is required to ensure a completed memory operation is not bound to an interrupt. ie. MEPC should not be PCM when committed. 2021-07-14 23:08:07 -05:00
Ross Thompson
6163629204 Finally have the ptw correctly walking through the dcache to update the itlb.
Still not working fully.
2021-07-14 22:26:07 -05:00
Ross Thompson
d41c9d5ad9 Added d cache StallW checks for any time the cache wants to go to STATE_READY. 2021-07-14 17:25:50 -05:00
Ross Thompson
d3a1a2c90a Fixed d cache not honoring StallW for uncache writes and reads. 2021-07-14 17:23:28 -05:00
Ross Thompson
1d7aa27316 Fixed a bug where the dcache did not update the read data if the CPU was stalled, but the memory not stalled. 2021-07-14 15:47:38 -05:00
Ross Thompson
e17de4eb11 Separated interruptM into PendingInterruptM and InterruptM. The d cache now takes in both exceptions and PendingInterrupts.
This solves the committedM issue.
2021-07-14 15:00:33 -05:00
Ross Thompson
ef598d0e79 Implemented uncached reads. 2021-07-13 23:03:09 -05:00
Ross Thompson
b6e5670bc3 Added CommitedM to data cache output. 2021-07-13 22:43:42 -05:00
Ross Thompson
278bbfbe3c Partially working changes to support uncached memory access. Not sure what CommitedM is. 2021-07-13 17:24:59 -05:00
Ross Thompson
b780e471b4 Fixed interaction between icache stall and dcache. On hit dcache needs to enter a cpu busy state when the cpu is stalled. 2021-07-13 14:51:42 -05:00
Ross Thompson
51249a0e04 Fixed the fetch buffer accidental overwrite on eviction. 2021-07-13 14:21:29 -05:00
Ross Thompson
2034a6584f Dcache AHB address generation was wrong. Needed to zero the offset. 2021-07-13 14:19:04 -05:00
Ross Thompson
ee09fa5f58 Moved StoreStall into the hazard unit instead of in the d cache. 2021-07-13 13:20:50 -05:00
Ross Thompson
2004b2e044 Fixed back to back store issue.
Note there is a bug in the lsuarb which needs to arbitrate a few execution stage signals.
2021-07-13 12:46:20 -05:00
Ross Thompson
40922cf064 Fixed subword write. subword read should not feed into subword write. 2021-07-13 11:21:44 -05:00
Ross Thompson
9fe6190763 Team work on solving the dcache data inconsistency problem. 2021-07-12 23:46:32 -05:00
Ross Thompson
8ca8b9075d Progress towards the test bench flush. 2021-07-12 14:22:13 -05:00
Ross Thompson
282bde7205 Fixed the spurious AHB requests to address 0. Somehow by not having a default
(else) in the fsm branch selection for STATE_READY in the d cache it was
possible to take an invalid branch through the fsm.
2021-07-10 22:34:47 -05:00
Ross Thompson
d9fa3af94d Loads are working.
There is a bug when the icache stalls 1 cycle before the d cache.
2021-07-10 22:15:44 -05:00
Ross Thompson
a82c4c99c2 Actually writes the correct data now on stores. 2021-07-10 17:48:47 -05:00
Ross Thompson
ee72178eec Write miss with eviction works. 2021-07-10 15:17:40 -05:00
Ross Thompson
0a6c86af94 Write Hits and Write Misses without eviction are working correctly! The next
step is to add eviction of dirty lines.
2021-07-10 10:56:25 -05:00
Ross Thompson
94b29ec418 Loads in modelsim, but the first store double does not function correctly. The write address is wrong so the cache is updated using the wrong address.
I think this is do to the cycle latency of stores.  We probably need extra muxes to select between MemPAdrM and MemPAdrW depending on if the write is a
full cache block or a word write from the CPU.
2021-07-09 17:14:54 -05:00
Ross Thompson
7e98610651 Design loads in modelsim, but trap is an X. 2021-07-09 15:37:16 -05:00
Ross Thompson
6abd23a61d Lint passes, but I only hope to have loads working. Stores, lr/sc, atomic, are not fully implemented.
Also faults and the dcache ptw interlock are not implemented.
2021-07-09 15:16:38 -05:00
Ross Thompson
6041aef263 completed read miss branch through dcache fsm.
The challenge now is to connect to ahb and lsu.
2021-07-08 17:53:08 -05:00
Ross Thompson
4c5aee3042 This d cache fsm is getting complex. 2021-07-08 15:26:16 -05:00
Ross Thompson
adcc7afffa Partial implementation of the data cache. Missing the fsm. 2021-07-07 17:52:16 -05:00