From: Fu Wei fu.wei@linaro.org
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 --- drivers/clocksource/arm_arch_timer.c | 78 ++++++++++++++++++++++++++++++++++-- 1 file changed, 75 insertions(+), 3 deletions(-)
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index 05f2f7a..8981173 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -1385,10 +1385,78 @@ 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"); @@ -1397,7 +1465,7 @@ 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; @@ -1440,6 +1508,10 @@ 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);