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

[Subhash Jadavani <subhashj@codeaurora.org>]

As Maya is going to fix the commit text,
Acked-by: Subhash Jadavani <subhashj@codeaurora.org>

On 1/17/2013 12:18 PM, Seungwon Jeon wrote:
> On Thursday, January 17, 2013 , Ulf Hansson wrote:
>> On 13 January 2013 22:47, Maya Erez <merez@codeaurora.org> wrote:
>>> -----Original Message-----
>>> From: Subhash Jadavani [mailto:subhashj@codeaurora.org]
>>> Sent: Saturday, January 12, 2013 9:07 AM
>>> To: Maya Erez
>>> Cc: linux-mmc@vger.kernel.org; linux-arm-msm@vger.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@codeaurora.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@linaro.org>
> Yes, it's reasonable.
> Cache feature is closely connected with eMMC.
>
> Acked-by: Seungwon Jeon <tgin.jun@samsung.com>
>
> Thanks,
> Seungwon Jeon
>> Kind regards
>> Ulf Hansson
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