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 <tglx@linutronix.de>
Tested-by: dann frazier <dann.frazier@canonical.com>
Tested-by: Hanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 34 insertions, 0 deletions

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;
 }