Re: [PATCH v4] pinctrl: mediatek: Implement wake handler and suspend resume

[Daniel Kurtz <djkurtz@xxxxxxxxxxxx>]

On Mon, Aug 17, 2015 at 3:52 PM, Yingjoe Chen <yingjoe.chen@xxxxxxxxxxxx> wrote:
> On Fri, 2015-08-14 at 16:38 +0800, maoguang.meng@xxxxxxxxxxxx wrote:
>> From: Maoguang Meng <maoguang.meng@xxxxxxxxxxxx>
>>
>> This patch implement irq_set_wake to get who is wakeup source and
>> setup on suspend resume.
>>
>> Signed-off-by: Maoguang Meng <maoguang.meng@xxxxxxxxxxxx>
>>
>> ---
>> changes since v3:
>> -add a comment in mtk_eint_chip_read_mask.
>> -delete ALIGN when allocate eint_offsets.ports.
>> -fix unrelated change.
>>
>> changes since v2:
>> -modify irq_wake to handle irq wakeup source.
>> -allocate two buffers separately.
>> -fix some codestyle.
>>
>> Changes since v1:
>> -implement irq_wake handler.
>> ---
>>
>>  drivers/pinctrl/mediatek/pinctrl-mt8173.c     |  1 +
>>  drivers/pinctrl/mediatek/pinctrl-mtk-common.c | 91 ++++++++++++++++++++++++++-
>>  drivers/pinctrl/mediatek/pinctrl-mtk-common.h |  4 ++
>>  3 files changed, 95 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/pinctrl/mediatek/pinctrl-mt8173.c b/drivers/pinctrl/mediatek/pinctrl-mt8173.c
>> index d0c811d..ad27184 100644
>> --- a/drivers/pinctrl/mediatek/pinctrl-mt8173.c
>> +++ b/drivers/pinctrl/mediatek/pinctrl-mt8173.c
>> @@ -385,6 +385,7 @@ static struct platform_driver mtk_pinctrl_driver = {
>>       .driver = {
>>               .name = "mediatek-mt8173-pinctrl",
>>               .of_match_table = mt8173_pctrl_match,
>> +             .pm = &mtk_eint_pm_ops,
>>       },
>>  };
>>
>> diff --git a/drivers/pinctrl/mediatek/pinctrl-mtk-common.c b/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
>> index ad1ea16..fe34ce9 100644
>> --- a/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
>> +++ b/drivers/pinctrl/mediatek/pinctrl-mtk-common.c
>> @@ -33,6 +33,7 @@
>>  #include <linux/mfd/syscon.h>
>>  #include <linux/delay.h>
>>  #include <linux/interrupt.h>
>> +#include <linux/pm.h>
>>  #include <dt-bindings/pinctrl/mt65xx.h>
>>
>>  #include "../core.h"
>> @@ -1062,6 +1063,77 @@ static int mtk_eint_set_type(struct irq_data *d,
>>       return 0;
>>  }
>>
>> +static int mtk_eint_irq_set_wake(struct irq_data *d, unsigned int on)
>> +{
>> +     struct mtk_pinctrl *pctl = irq_data_get_irq_chip_data(d);
>> +     int shift = d->hwirq & 0x1f;
>> +     int reg = d->hwirq >> 5;
>> +
>> +     if (on)
>> +             pctl->wake_mask[reg] |= BIT(shift);
>> +     else
>> +             pctl->wake_mask[reg] &= ~BIT(shift);
>> +
>> +     return 0;
>> +}
>
> Hi Maoguang,
>
> You changed from set_bit/clear_bit to this, but didn't add any locking.
> Since this is basic read/modify/write, is it OK to do it without
> locking?

I believe calling .irq_set_wake() concurrently with itself is
protected by irq_get_desc_buslock():

 int irq_set_irq_wake(unsigned int irq, unsigned int on)
 {
         unsigned long flags;
         struct irq_desc *desc = irq_get_desc_buslock(irq, &flags,
IRQ_GET_DESC_CHECK_GLOBAL);
         int ret = 0;
...
                         ret = set_irq_wake_real(irq, on);
...
         irq_put_desc_busunlock(desc, flags);
         return ret;
 }


I'm not 100% sure about the .suspend/.resume paths, but I don't think
they can occur during .irq_set_wake(), either.
Nor were they protected by the set_bit/clear_bit implementation.

-Dan


>
> Joe.C
>
>
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