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Message-ID: <CADyBb7uXaPVT1ppJav5=ckdvBcfv+6fSsMc3xbDjFEO2G_zjSQ@mail.gmail.com>
Date: Mon, 21 Nov 2016 22:38:51 +0800
From: Fu Wei <fu.wei@...aro.org>
To: Mark Rutland <mark.rutland@....com>
Cc: "Rafael J. Wysocki" <rjw@...ysocki.net>,
Len Brown <lenb@...nel.org>,
Daniel Lezcano <daniel.lezcano@...aro.org>,
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Sudeep Holla <sudeep.holla@....com>,
Hanjun Guo <hanjun.guo@...aro.org>,
linux-arm-kernel@...ts.infradead.org,
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G Gregory <graeme.gregory@...aro.org>,
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Julien Grall <julien.grall@....com>
Subject: Re: [PATCH v16 08/15] clocksource/drivers/arm_arch_timer: Refactor
arch_timer_needs_probing, and call it only if acpi disabled.
Hi Mark,
On 19 November 2016 at 03:56, Mark Rutland <mark.rutland@....com> wrote:
> On Wed, Nov 16, 2016 at 09:49:01PM +0800, fu.wei@...aro.org wrote:
>> From: Fu Wei <fu.wei@...aro.org>
>>
>> The patch refactor original arch_timer_needs_probing function:
>> (1) Separate out arch_timer_needs_probing from arch_timer_common_init,
>> and call it only if acpi disabled.
>> (2) Rename arch_timer_needs_probing to arch_timer_needs_of_probing.
>
> Please write a real commit message.
OK, how about this:
clocksource/drivers/arm_arch_timer: Refactor
arch_timer_needs_probing, only use it in the DT init code
Currently, the arch_timer_common_init uses arch_timer_needs_probing call to
wait for both timers been probed which is only for booting from DT.
For booting from ACPI, we don't need these in arch_timer_common_init, these code
should be only in the DT init code.
This patch seperates arch_timer_needs_probing related code out into a
new function
named arch_timer_needs_of_probing, and then reworks arch_timer_of_init
to use it,
so that we can keep this only in the DT init code.
>
>> Signed-off-by: Fu Wei <fu.wei@...aro.org>
>> ---
>> drivers/clocksource/arm_arch_timer.c | 34 +++++++++++++++++++---------------
>> 1 file changed, 19 insertions(+), 15 deletions(-)
>>
>> diff --git a/drivers/clocksource/arm_arch_timer.c b/drivers/clocksource/arm_arch_timer.c
>> index fe4e812..9ddc091 100644
>> --- a/drivers/clocksource/arm_arch_timer.c
>> +++ b/drivers/clocksource/arm_arch_timer.c
>> @@ -792,15 +792,28 @@ static const struct of_device_id arch_timer_mem_of_match[] __initconst = {
>> {},
>> };
>>
>> -static bool __init
>> -arch_timer_needs_probing(int type, const struct of_device_id *matches)
>> +static bool __init arch_timer_needs_of_probing(void)
>> {
>> struct device_node *dn;
>> bool needs_probing = false;
>> + unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;
>> +
>> + /* We have two timers, and both device-tree nodes are probed. */
>> + if ((arch_timers_present & mask) == mask)
>> + return false;
>> +
>> + /*
>> + * Only one type of timer is probed,
>> + * check if we have another type of timer node in device-tree.
>> + */
>> + if (arch_timers_present & ARCH_TIMER_TYPE_CP15)
>> + dn = of_find_matching_node(NULL, arch_timer_mem_of_match);
>> + else
>> + dn = of_find_matching_node(NULL, arch_timer_of_match);
>>
>> - dn = of_find_matching_node(NULL, matches);
>> - if (dn && of_device_is_available(dn) && !(arch_timers_present & type))
>> + if (dn && of_device_is_available(dn))
>> needs_probing = true;
>> +
>> of_node_put(dn);
>>
>> return needs_probing;
>> @@ -808,17 +821,8 @@ arch_timer_needs_probing(int type, const struct of_device_id *matches)
>>
>> static int __init arch_timer_common_init(void)
>> {
>> - unsigned int mask = ARCH_TIMER_TYPE_CP15 | ARCH_TIMER_TYPE_MEM;
>> -
>> - /* Wait until both nodes are probed if we have two timers */
>> - if ((arch_timers_present & mask) != mask) {
>> - if (arch_timer_needs_probing(ARCH_TIMER_TYPE_MEM,
>> - arch_timer_mem_of_match))
>> - return 0;
>> - if (arch_timer_needs_probing(ARCH_TIMER_TYPE_CP15,
>> - arch_timer_of_match))
>> - return 0;
>> - }
>
> Why can't we just move this into the DT-specific caller of
> arch_timer_common_init()?
yes, I have thought about this, but that means we have to split arch_timer_init,
and use arch_timer_register and arch_timer_common_init directly in
arch_timer_of_init.
In another word, I also need to modify arch_timer_of_init, not only
arch_timer_common_init,
but let me have a try in v17, see if you like it.
>
> Thanks
> Mark.
>
>> + if (acpi_disabled && arch_timer_needs_of_probing())
>> + return 0;
>>
>> arch_timer_banner(arch_timers_present);
>> arch_counter_register(arch_timers_present);
>> --
>> 2.7.4
>>
--
Best regards,
Fu Wei
Software Engineer
Red Hat
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