From 5a38bcac1f2f0bd0d24700690e36a277ffd0396d Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Tue, 21 Feb 2017 14:37:30 +0000 Subject: [PATCH] arm64: arch_timer: Allow erratum matching with ACPI OEM information Just as we're able to identify a broken platform using some DT information, let's enable a way to spot the offenders with ACPI. The difference is that we can only match on some OEM info instead of implementation-specific properties. So in order to avoid the insane multiplication of errata structures, we allow an array of OEM descriptions to be attached to an erratum structure. Acked-by: Thomas Gleixner Tested-by: dann frazier Tested-by: Hanjun Guo Reviewed-by: Hanjun Guo Signed-off-by: Marc Zyngier --- arch/arm64/include/asm/arch_timer.h | 1 + drivers/clocksource/arm_arch_timer.c | 34 ++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+) diff --git a/arch/arm64/include/asm/arch_timer.h b/arch/arm64/include/asm/arch_timer.h index 6bd1a9a1573a..74d08e44a651 100644 --- a/arch/arm64/include/asm/arch_timer.h +++ b/arch/arm64/include/asm/arch_timer.h @@ -41,6 +41,7 @@ extern struct static_key_false arch_timer_read_ool_enabled; enum arch_timer_erratum_match_type { ate_match_dt, ate_match_local_cap_id, + ate_match_acpi_oem_info, }; struct clock_event_device; diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 8459d19a84f5..887f6d00a71d 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -190,6 +190,12 @@ static struct cyclecounter cyclecounter __ro_after_init = { .mask = CLOCKSOURCE_MASK(56), }; +struct ate_acpi_oem_info { + char oem_id[ACPI_OEM_ID_SIZE + 1]; + char oem_table_id[ACPI_OEM_TABLE_ID_SIZE + 1]; + u32 oem_revision; +}; + #ifdef CONFIG_FSL_ERRATUM_A008585 /* * The number of retries is an arbitrary value well beyond the highest number @@ -371,6 +377,28 @@ bool arch_timer_check_local_cap_erratum(const struct arch_timer_erratum_workarou return this_cpu_has_cap((uintptr_t)wa->id); } + +static +bool arch_timer_check_acpi_oem_erratum(const struct arch_timer_erratum_workaround *wa, + const void *arg) +{ + static const struct ate_acpi_oem_info empty_oem_info = {}; + const struct ate_acpi_oem_info *info = wa->id; + const struct acpi_table_header *table = arg; + + /* Iterate over the ACPI OEM info array, looking for a match */ + while (memcmp(info, &empty_oem_info, sizeof(*info))) { + if (!memcmp(info->oem_id, table->oem_id, ACPI_OEM_ID_SIZE) && + !memcmp(info->oem_table_id, table->oem_table_id, ACPI_OEM_TABLE_ID_SIZE) && + info->oem_revision == table->oem_revision) + return true; + + info++; + } + + return false; +} + static const struct arch_timer_erratum_workaround * arch_timer_iterate_errata(enum arch_timer_erratum_match_type type, ate_match_fn_t match_fn, @@ -431,6 +459,9 @@ static void arch_timer_check_ool_workaround(enum arch_timer_erratum_match_type t match_fn = arch_timer_check_local_cap_erratum; local = true; break; + case ate_match_acpi_oem_info: + match_fn = arch_timer_check_acpi_oem_erratum; + break; default: WARN_ON(1); return; @@ -1277,6 +1308,9 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) /* Always-on capability */ arch_timer_c3stop = !(gtdt->non_secure_el1_flags & ACPI_GTDT_ALWAYS_ON); + /* Check for globally applicable workarounds */ + arch_timer_check_ool_workaround(ate_match_acpi_oem_info, table); + arch_timer_init(); return 0; }