diff options
| author | Atish Patra <atish.patra@wdc.com> | 2021-07-10 19:18:03 +0300 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2021-07-11 07:41:10 +0300 |
| commit | fde28fadc2603c7c7a4afa7c2e7b96cc7b11d2e2 (patch) | |
| tree | 5b473fe4342a31d47ba988d93c8730409e28a993 | |
| parent | 3e8b31aca988955800d15329f1d4e48b4fbe7233 (diff) | |
| download | opensbi-fde28fadc2603c7c7a4afa7c2e7b96cc7b11d2e2.tar.xz | |
lib: sbi: Detect mcountinihibit support at runtime
RISC-V ISA specification v1.11 defined mcountinhibit CSR that allows
software to stop any counter from incrementing. The SBI PMU extension
depends on this CSR support in hardware.
Define mcountinhibit as a hart specific feature and detect it at runtime.
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Atish Patra <atish.patra@wdc.com>
| -rw-r--r-- | include/sbi/sbi_hart.h | 4 | ||||
| -rw-r--r-- | lib/sbi/sbi_hart.c | 11 |
2 files changed, 14 insertions, 1 deletions
diff --git a/include/sbi/sbi_hart.h b/include/sbi/sbi_hart.h index 031c7b0..9e317c5 100644 --- a/include/sbi/sbi_hart.h +++ b/include/sbi/sbi_hart.h @@ -18,8 +18,10 @@ enum sbi_hart_features { SBI_HART_HAS_SCOUNTEREN = (1 << 0), /** Hart has M-mode counter enable */ SBI_HART_HAS_MCOUNTEREN = (1 << 1), + /** Hart has counter inhibit CSR */ + SBI_HART_HAS_MCOUNTINHIBIT = (1 << 2), /** HART has timer csr implementation in hardware */ - SBI_HART_HAS_TIME = (1 << 2), + SBI_HART_HAS_TIME = (1 << 3), /** Last index of Hart features*/ SBI_HART_HAS_LAST_FEATURE = SBI_HART_HAS_TIME, diff --git a/lib/sbi/sbi_hart.c b/lib/sbi/sbi_hart.c index 56878b4..0bd1db1 100644 --- a/lib/sbi/sbi_hart.c +++ b/lib/sbi/sbi_hart.c @@ -259,6 +259,9 @@ static inline char *sbi_hart_feature_id2string(unsigned long feature) case SBI_HART_HAS_MCOUNTEREN: fstr = "mcounteren"; break; + case SBI_HART_HAS_MCOUNTINHIBIT: + fstr = "mcountinhibit"; + break; case SBI_HART_HAS_TIME: fstr = "time"; break; @@ -421,6 +424,14 @@ __mhpm_skip: hfeatures->features |= SBI_HART_HAS_MCOUNTEREN; } + /* Detect if hart supports MCOUNTINHIBIT feature */ + val = csr_read_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap); + if (!trap.cause) { + csr_write_allowed(CSR_MCOUNTINHIBIT, (unsigned long)&trap, val); + if (!trap.cause) + hfeatures->features |= SBI_HART_HAS_MCOUNTINHIBIT; + } + /* Detect if hart supports time CSR */ csr_read_allowed(CSR_TIME, (unsigned long)&trap); if (!trap.cause) |