linux-kernel - Re: [PATCH v20 16/17] clocksource/drivers/arm_arch_timer: Add GTDT support for memory-mapped timer

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Message-ID: <CADyBb7tpDynA0EEUkFZXpUAksjvXeUzuoC82GnbVA2O1w2T22g@mail.gmail.com>
Date:   Thu, 19 Jan 2017 18:02:59 +0800
From:   Fu Wei <fu.wei@...aro.org>
To:     Hanjun Guo <hanjun.guo@...aro.org>
Cc:     "Rafael J. Wysocki" <rjw@...ysocki.net>,
        Len Brown <lenb@...nel.org>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <marc.zyngier@....com>,
        Mark Rutland <mark.rutland@....com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Sudeep Holla <sudeep.holla@....com>,
        linux-arm-kernel@...ts.infradead.org,
        Linaro ACPI Mailman List <linaro-acpi@...ts.linaro.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        rruigrok@...eaurora.org, "Abdulhamid, Harb" <harba@...eaurora.org>,
        Christopher Covington <cov@...eaurora.org>,
        Timur Tabi <timur@...eaurora.org>,
        G Gregory <graeme.gregory@...aro.org>,
        Al Stone <al.stone@...aro.org>, Jon Masters <jcm@...hat.com>,
        Wei Huang <wei@...hat.com>, Arnd Bergmann <arnd@...db.de>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will.deacon@....com>,
        Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>,
        Leo Duran <leo.duran@....com>,
        Wim Van Sebroeck <wim@...ana.be>,
        Guenter Roeck <linux@...ck-us.net>,
        linux-watchdog@...r.kernel.org, Tomasz Nowicki <tn@...ihalf.com>,
        Christoffer Dall <christoffer.dall@...aro.org>,
        Julien Grall <julien.grall@....com>
Subject: Re: [PATCH v20 16/17] clocksource/drivers/arm_arch_timer: Add GTDT
 support for memory-mapped timer

Hi Hanjun,

On 19 January 2017 at 17:16, Hanjun Guo <hanjun.guo@...aro.org> wrote:
> On 2017/1/18 21:25, fu.wei@...aro.org wrote:
>>
>> From: Fu Wei <fu.wei@...aro.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@...aro.org>
>> ---
>>  drivers/clocksource/arm_arch_timer.c | 35
>> ++++++++++++++++++++++++++++++++---
>>  1 file changed, 32 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/clocksource/arm_arch_timer.c
>> b/drivers/clocksource/arm_arch_timer.c
>> index 79dc004..7ca2da7 100644
>> --- a/drivers/clocksource/arm_arch_timer.c
>> +++ b/drivers/clocksource/arm_arch_timer.c
>> @@ -1077,10 +1077,36 @@ 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(int platform_timer_count)
>> +{
>> +       struct arch_timer_mem *timer_mem;
>> +       int timer_count, i, ret;
>> +
>
>
> if (!platform_timer_count)
>         return 0;
>
> Did I miss something?

Ah, thanks, I guess I miss this check below.

>
> Thanks
> Hanjun
>
>
>> +       timer_mem = kcalloc(platform_timer_count, sizeof(*timer_mem),
>> +                           GFP_KERNEL);
>> +       if (!timer_mem)
>> +               return -ENOMEM;
>> +
>> +       ret = acpi_arch_timer_mem_init(timer_mem, &timer_count);
>> +       if (ret || !timer_count)
>> +               goto error;
>> +
>> +       for (i = 0; i < timer_count; i++) {
>> +               ret = arch_timer_mem_init(timer_mem);
>> +               if (!ret)
>> +                       break;
>> +               timer_mem++;
>> +       }
>> +
>> +error:
>> +       kfree(timer_mem);
>> +       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");
>> @@ -1089,7 +1115,7 @@ 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;
>> @@ -1122,6 +1148,9 @@ static int __init arch_timer_acpi_init(struct
>> acpi_table_header *table)
>>         if (ret)
>>                 return ret;
>>
>> +       if (arch_timer_mem_acpi_init(platform_timer_count))

+       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);
>>
>



-- 
Best regards,

Fu Wei
Software Engineer
Red Hat