Hi Mark,
On 19 November 2016 at 04:20, Mark Rutland mark.rutland@arm.com wrote:
On Wed, Nov 16, 2016 at 09:49:07PM +0800, fu.wei@linaro.org wrote:
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
drivers/clocksource/arm_arch_timer.c | 26 +++++++++++++++++++++++++- 1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c index c494ca8..0aad60a 100644 --- a/drivers/clocksource/arm_arch_timer.c +++ b/drivers/clocksource/arm_arch_timer.c @@ -1067,7 +1067,28 @@ 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_acpi_init(void) +{
struct arch_timer_mem *timer_mem;int ret = 0;int i = 0;timer_mem = kzalloc(sizeof(*timer_mem), GFP_KERNEL);Why do you need it zeroed? You don't clear it between iterations, so either you don't need this, or you have a bug in the loop.
if (!timer_mem)return -ENOMEM;while (!gtdt_arch_timer_mem_init(timer_mem, i)) {Huh?
Why doesn't GTDT expose a function to fill in the entire arch_timer_mem in one go?
Yes, that is a good idea, but I need to find a way to get the number of GT block in GTDT, then allocate a struct arch_timer_mem array for all GT block
There shouldn't be multiple instances, as far as I am aware. Am I mistaken?
I don't see any doc says : there is only one memory-mapped timer in a soc. Maybe we have more than one GT block in GTDT or (in another word) we may have more than one memory-mapped timer in a soc, right ??
Please correct me, If I miss something.
ret = arch_timer_mem_init(timer_mem);if (ret)break;i++;}kfree(timer_mem);return ret;+}
Regardless, arch_timer_mem is small enough that you don't need dynamic allocaiton. Just put it on the stack, e.g.
static int __init arch_timer_mem_acpi_init(void) { int i = 0; struct arch_timer_mem timer_mem;
while (!gtdt_arch_timer_mem_init(timer_mem, i)) { int ret = arch_timer_mem_init(); if (ret) return ret; i++ } return 0;}
Thanks, Mark.