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Commit c2743a36 authored by Fu Wei's avatar Fu Wei Committed by Mark Rutland
Browse files

clocksource: arm_arch_timer: add GTDT support for memory-mapped timer 



The patch add memory-mapped timer register support by using the
information provided by the new GTDT driver of ACPI.

Signed-off-by: default avatarFu Wei <fu.wei@linaro.org>
Reviewed-by: default avatarHanjun Guo <hanjun.guo@linaro.org>
[Mark: verify CNTFRQ, only register the first frame]
Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
parent a712c3ed

drivers/clocksource/arm_arch_timer.c

+76 −3
Original line number Diff line number Diff line
@@ -1386,10 +1386,79 @@ CLOCKSOURCE_OF_DECLARE(armv7_arch_timer_mem, "arm,armv7-timer-mem", 
		       arch_timer_mem_of_init);



#ifdef CONFIG_ACPI_GTDT

/* Initialize per-processor generic timer */

static int __init

arch_timer_mem_verify_cntfrq(struct arch_timer_mem *timer_mem)

{

	struct arch_timer_mem_frame *frame;

	u32 rate;

	int i;



	for (i = 0; i < ARCH_TIMER_MEM_MAX_FRAMES; i++) {

		frame = &timer_mem->frame[i];



		if (!frame->valid)

			continue;



		rate = arch_timer_mem_frame_get_cntfrq(frame);

		if (rate == arch_timer_rate)

			continue;



		pr_err(FW_BUG "CNTFRQ mismatch: frame @ %pa: (0x%08lx), CPU: (0x%08lx)\n",

			&frame->cntbase,

			(unsigned long)rate, (unsigned long)arch_timer_rate);



		return -EINVAL;

	}



	return 0;

}



static int __init arch_timer_mem_acpi_init(int platform_timer_count)

{

	struct arch_timer_mem *timers, *timer;

	struct arch_timer_mem_frame *frame;

	int timer_count, i, ret = 0;



	timers = kcalloc(platform_timer_count, sizeof(*timers),

			    GFP_KERNEL);

	if (!timers)

		return -ENOMEM;



	ret = acpi_arch_timer_mem_init(timers, &timer_count);

	if (ret || !timer_count)

		goto out;



	for (i = 0; i < timer_count; i++) {

		ret = arch_timer_mem_verify_cntfrq(&timers[i]);

		if (ret) {

			pr_err("Disabling MMIO timers due to CNTFRQ mismatch\n");

			goto out;

		}

	}



	/*

	 * While unlikely, it's theoretically possible that none of the frames

	 * in a timer expose the combination of feature we want.

	 */

	for (i = i; i < timer_count; i++) {

		timer = &timers[i];



		frame = arch_timer_mem_find_best_frame(timer);

		if (frame)

			break;

	}



	if (frame)

		ret = arch_timer_mem_frame_register(frame);

out:

	kfree(timers);

	return ret;

}



/* Initialize per-processor generic timer and memory-mapped timer(if present) */

static int __init arch_timer_acpi_init(struct acpi_table_header *table)

{

	int ret;

	int ret, platform_timer_count;



	if (arch_timers_present & ARCH_TIMER_TYPE_CP15) {

		pr_warn("already initialized, skipping\n");
@@ -1398,7 +1467,7 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) 


	arch_timers_present |= ARCH_TIMER_TYPE_CP15;



	ret = acpi_gtdt_init(table, NULL);

	ret = acpi_gtdt_init(table, &platform_timer_count);

	if (ret) {

		pr_err("Failed to init GTDT table.\n");

		return ret;
@@ -1441,6 +1510,10 @@ static int __init arch_timer_acpi_init(struct acpi_table_header *table) 
	if (ret)

		return ret;



	if (platform_timer_count &&

	    arch_timer_mem_acpi_init(platform_timer_count))

		pr_err("Failed to initialize memory-mapped timer.\n");



	return arch_timer_common_init();

}

CLOCKSOURCE_ACPI_DECLARE(arch_timer, ACPI_SIG_GTDT, arch_timer_acpi_init);