linux-kernel - Re: [PATCH] mmc: core: disable the cache before suspend only after stopping BKOPS

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Message-ID: <CAPDyKFrjFhBMHqn+CYB5LPwiWmAOWmiL2pm5Kww5u9jUrQ4p3w@mail.gmail.com>
Date:	Wed, 16 Jan 2013 22:37:31 +0100
From:	Ulf Hansson <ulf.hansson@...aro.org>
To:	Maya Erez <merez@...eaurora.org>
Cc:	Subhash Jadavani <subhashj@...eaurora.org>,
	linux-mmc@...r.kernel.org, linux-arm-msm@...r.kernel.org,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] mmc: core: disable the cache before suspend only after
 stopping BKOPS

On 13 January 2013 22:47, Maya Erez <merez@...eaurora.org> wrote:
> -----Original Message-----
> From: Subhash Jadavani [mailto:subhashj@...eaurora.org]
> Sent: Saturday, January 12, 2013 9:07 AM
> To: Maya Erez
> Cc: linux-mmc@...r.kernel.org; linux-arm-msm@...r.kernel.org; open list
> Subject: Re: [PATCH] mmc: core: disable the cache before suspend only after
> stopping BKOPS
>
> On 1/12/2013 2:12 AM, Maya Erez wrote:
>> mmc_cache_ctrl was called in runtime suspend before MMC interrupted
>> BKOPS in case it is still running on the card. This caused the cache
>> disable to timeout.
> I guess even if the idle time bkops polling is not implemented, this patch
> is good to have. cache control is the eMMC feature and in that sense, it
> should have been part of MMC's bus resume (mmc_resume) rather than generic
> mmc_suspend_host().
>
> Patch as such is fine and if you agree, you may want to remove the
> mentioning of bkops as part of commit text and may just want to mention
> above reason as the main motivation for this patch.
>
> Agreed, I will change the commit text in the next uploaded version.
>
>> Therefore, mmc_cache_ctrl has to move to mmc_suspend where we are sure
>> that the card can go into suspend and there is no pending activity.
>>
>> Signed-off-by: Maya Erez <merez@...eaurora.org>
>> ---
>>   drivers/mmc/core/core.c |    7 +------
>>   drivers/mmc/core/mmc.c  |    8 +++++++-
>>   2 files changed, 8 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index
>> aaed768..b438bb2 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -2388,6 +2388,7 @@ EXPORT_SYMBOL(mmc_flush_cache);
>>    * Turn the cache ON/OFF.
>>    * Turning the cache OFF shall trigger flushing of the data
>>    * to the non-volatile storage.
>> + * This function should be called with host claimed
>>    */
>>   int mmc_cache_ctrl(struct mmc_host *host, u8 enable)
>>   {
>> @@ -2399,7 +2400,6 @@ int mmc_cache_ctrl(struct mmc_host *host, u8 enable)
>>                       mmc_card_is_removable(host))
>>               return err;
>>
>> -     mmc_claim_host(host);
>>       if (card && mmc_card_mmc(card) &&
>>                       (card->ext_csd.cache_size > 0)) {
>>               enable = !!enable;
>> @@ -2417,7 +2417,6 @@ int mmc_cache_ctrl(struct mmc_host *host, u8 enable)
>>                               card->ext_csd.cache_ctrl = enable;
>>               }
>>       }
>> -     mmc_release_host(host);
>>
>>       return err;
>>   }
>> @@ -2436,10 +2435,6 @@ int mmc_suspend_host(struct mmc_host *host)
>>       cancel_delayed_work(&host->detect);
>>       mmc_flush_scheduled_work();
>>
>> -     err = mmc_cache_ctrl(host, 0);
>> -     if (err)
>> -             goto out;
>> -
>>       mmc_bus_get(host);
>>       if (host->bus_ops && !host->bus_dead) {
>>               if (host->bus_ops->suspend) {
>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c index
>> e6e3911..dc17d40 100644
>> --- a/drivers/mmc/core/mmc.c
>> +++ b/drivers/mmc/core/mmc.c
>> @@ -1379,6 +1379,11 @@ static int mmc_suspend(struct mmc_host *host)
>>       BUG_ON(!host->card);
>>
>>       mmc_claim_host(host);
>> +
>> +     err = mmc_cache_ctrl(host, 0);
>> +     if (err)
>> +             goto out;
>> +
>>       if (mmc_can_poweroff_notify(host->card))
>>               err = mmc_poweroff_notify(host->card,
> EXT_CSD_POWER_OFF_SHORT);
>>       else if (mmc_card_can_sleep(host))
>> @@ -1386,8 +1391,9 @@ static int mmc_suspend(struct mmc_host *host)
>>       else if (!mmc_host_is_spi(host))
>>               err = mmc_deselect_cards(host);
>>       host->card->state &= ~(MMC_STATE_HIGHSPEED |
> MMC_STATE_HIGHSPEED_200);
>> -     mmc_release_host(host);
>>
>> +out:
>> +     mmc_release_host(host);
>>       return err;
>>   }
>>
> --
> QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>
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I agree that some update to the commit msg is wanted; since this fixup
is not related to runtime suspend as such.
Anyway, you have my ack!

Acked-by: Ulf Hansson <ulf.hansson@...aro.org>

Kind regards
Ulf Hansson
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