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

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

Signed-off-by: Fu Wei <fu.wei@linaro.org>
Reviewed-by: Hanjun Guo <hanjun.guo@linaro.org>
[Mark: verify CNTFRQ, only register the first frame]
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
This commit is contained in:
Fu Wei 2017-04-01 01:51:04 +08:00 committed by Mark Rutland
parent a712c3ed9b
commit c2743a3676
1 changed files with 76 additions and 3 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

79
drivers/clocksource/arm_arch_timer.c
View file

@ -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);