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

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Date:   Thu, 19 Jan 2017 20:42:59 +0800
From:   Hanjun Guo <hanjun.guo@...aro.org>
To:     Fu Wei <fu.wei@...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

On 2017/1/19 18:02, Fu Wei wrote:
> 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))

It's better.

Thanks
Hanjun