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| author | Andre Przywara <andre.przywara@arm.com> | 2023-10-16 17:31:27 +0200 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2023-10-18 11:58:59 +0200 |
| commit | 851354cbd12bb9500909733c3d4054306f61df87 (patch) | |
| tree | d0c608711ea958cb5b3fa43fc6c84061b606d982 /drivers/clocksource | |
| parent | arm64: Remove system_uses_lse_atomics() (diff) | |
| download | linux-851354cbd12bb9500909733c3d4054306f61df87.tar.xz linux-851354cbd12bb9500909733c3d4054306f61df87.zip | |
clocksource/drivers/arm_arch_timer: limit XGene-1 workaround
The AppliedMicro XGene-1 CPU has an erratum where the timer condition
would only consider TVAL, not CVAL. We currently apply a workaround when
seeing the PartNum field of MIDR_EL1 being 0x000, under the assumption
that this would match only the XGene-1 CPU model.
However even the Ampere eMAG (aka XGene-3) uses that same part number, and
only differs in the "Variant" and "Revision" fields: XGene-1's MIDR is
0x500f0000, our eMAG reports 0x503f0002. Experiments show the latter
doesn't show the faulty behaviour.
Increase the specificity of the check to only consider partnum 0x000 and
variant 0x00, to exclude the Ampere eMAG.
Fixes: 012f18850452 ("clocksource/drivers/arm_arch_timer: Work around broken CVAL implementations")
Reported-by: Ross Burton <ross.burton@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20231016153127.116101-1-andre.przywara@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'drivers/clocksource')
| -rw-r--r-- | drivers/clocksource/arm_arch_timer.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 7dd2c615bce2..071b04f1ee73 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -836,8 +836,9 @@ static u64 __arch_timer_check_delta(void) * Note that TVAL is signed, thus has only 31 of its * 32 bits to express magnitude. */ - MIDR_ALL_VERSIONS(MIDR_CPU_MODEL(ARM_CPU_IMP_APM, - APM_CPU_PART_POTENZA)), + MIDR_REV_RANGE(MIDR_CPU_MODEL(ARM_CPU_IMP_APM, + APM_CPU_PART_XGENE), + APM_CPU_VAR_POTENZA, 0x0, 0xf), {}, }; |