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Commit 5a38bcac authored by Marc Zyngier's avatar Marc Zyngier
Browse files

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: default avatarThomas Gleixner <tglx@linutronix.de>
Tested-by: default avatardann frazier <dann.frazier@canonical.com>
Tested-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
Reviewed-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
Signed-off-by: default avatarMarc Zyngier <marc.zyngier@arm.com>
parent fa8d815f

arch/arm64/include/asm/arch_timer.h

+1 −0
Original line number Diff line number Diff line
@@ -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;

drivers/clocksource/arm_arch_timer.c

+34 −0
Original line number Diff line number Diff line
@@ -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;

}