Re: [PATCH] MMC-4.5 Power OFF Notify rework

[Saugata Das <saugata.das@linaro.org>]

On 27 April 2012 13:10, Ulf Hansson <ulf.hansson@stericsson.com> wrote:
> On 04/27/2012 06:40 AM, Girish K S wrote:
>>
>> On 23 April 2012 19:41, Ulf Hansson<ulf.hansson@stericsson.com>  wrote:
>>>
>>> Hi Girish,
>>>
>>> Please see some comments below...
>>>
>>>
>>> On 04/20/2012 01:33 PM, Girish K S wrote:
>>>>
>>>>
>>>> On 19 April 2012 18:11, Girish K S<girish.shivananjappa@linaro.org>
>>>>  wrote:
>>>>>
>>>>>
>>>>> This is a rework of the existing POWER OFF NOTIFY patch. The current
>>>>> problem
>>>>> with the patch comes from the ambiguity on the usage of POWER OFF
>>>>> NOTIFY
>>>>> together with SLEEP and misunderstanding on the usage of MMC_POWER_OFF
>>>>> power_mode from mmc_set_ios in different host controller drivers.
>>>>>
>>>>> This new patch works around this problem by adding a new host CAP,
>>>>> MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND, which when set sends a
>>>>> POWER OFF NOTIFY from mmc_suspend instead of SLEEP. It is expected that
>>>>> host
>>>>> controller drivers will set this CAP, if they switch off both Vcc and
>>>>> Vccq
>>>>> from MMC_POWER_OFF condition within mmc_set_ios. However, note that
>>>>> there
>>>>> is no harm in sending MMC_POWER_NOTIFY even if Vccq is not switched
>>>>> off.
>>>>>
>>>>> This patch also sends POWER OFF NOTIFY from power management routines
>>>>> (e.g.
>>>>> mmc_power_save_host, mmc_pm_notify/PM_SUSPEND_PREPARE, mmc_stop_host),
>>>>> which
>>>>> does reinitialization of the eMMC on the return path of the power
>>>>> management
>>>>> routines (e.g. mmc_power_restore_host, mmc_pm_notify/PM_POST_RESTORE,
>>>>> mmc_start_host).
>>>>>
>>>>> This patch sets POWER_OFF_NOTIFICATION to POWER_OFF_SHORT if it is sent
>>>>> from
>>>>> the suspend sequence. If it is sent from shutdown sequence then it is
>>>>> set
>>>>> to
>>>>> POWER_OFF_LONG.
>>>>>
>>>>> Previuos implementation of PowerOff Notify as a core function is
>>>>> replaced
>>>>> as
>>>>> a device's bus operation.
>>>
>>>
>>> Great, I like this! :-)
>>>
>>>>>
>>>>> Signed-off-by: Saugata Das<saugata.das@linaro.org>
>>>>> Signed-off-by: Girish K S<girish.shivananjappa@linaro.org>
>>>>> ---
>>>>>  drivers/mmc/core/core.c  |   83
>>>>> ++++++++++-----------------------------------
>>>>>  drivers/mmc/core/core.h  |    1 +
>>>>>  drivers/mmc/core/mmc.c   |   75
>>>>> +++++++++++++++++++++++++++++++++++-------
>>>>>  include/linux/mmc/host.h |    1 +
>>>>>  4 files changed, 84 insertions(+), 76 deletions(-)
>>>>>
>>>>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>>>>> index e541efb..4b8b2c1 100644
>>>>> --- a/drivers/mmc/core/core.c
>>>>> +++ b/drivers/mmc/core/core.c
>>>>> @@ -1100,48 +1100,6 @@ void mmc_set_driver_type(struct mmc_host *host,
>>>>> unsigned int drv_type)
>>>>>        mmc_host_clk_release(host);
>>>>>  }
>>>>>
>>>>> -static void mmc_poweroff_notify(struct mmc_host *host)
>>>>> -{
>>>>> -       struct mmc_card *card;
>>>>> -       unsigned int timeout;
>>>>> -       unsigned int notify_type = EXT_CSD_NO_POWER_NOTIFICATION;
>>>>> -       int err = 0;
>>>>> -
>>>>> -       card = host->card;
>>>>> -       mmc_claim_host(host);
>>>>> -
>>>>> -       /*
>>>>> -        * Send power notify command only if card
>>>>> -        * is mmc and notify state is powered ON
>>>>> -        */
>>>>> -       if (card&&   mmc_card_mmc(card)&&
>>>>> -           (card->poweroff_notify_state == MMC_POWERED_ON)) {
>>>>> -
>>>>> -               if (host->power_notify_type ==
>>>>> MMC_HOST_PW_NOTIFY_SHORT)
>>>>> {
>>>>> -                       notify_type = EXT_CSD_POWER_OFF_SHORT;
>>>>> -                       timeout = card->ext_csd.generic_cmd6_time;
>>>>> -                       card->poweroff_notify_state =
>>>>> MMC_POWEROFF_SHORT;
>>>>> -               } else {
>>>>> -                       notify_type = EXT_CSD_POWER_OFF_LONG;
>>>>> -                       timeout = card->ext_csd.power_off_longtime;
>>>>> -                       card->poweroff_notify_state =
>>>>> MMC_POWEROFF_LONG;
>>>>> -               }
>>>>> -
>>>>> -               err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>>>>> -                                EXT_CSD_POWER_OFF_NOTIFICATION,
>>>>> -                                notify_type, timeout);
>>>>> -
>>>>> -               if (err&&   err != -EBADMSG)
>>>>>
>>>>> -                       pr_err("Device failed to respond within %d
>>>>> poweroff "
>>>>> -                              "time. Forcefully powering down the
>>>>> device\n",
>>>>> -                              timeout);
>>>>> -
>>>>> -               /* Set the card state to no notification after the
>>>>> poweroff */
>>>>> -               card->poweroff_notify_state =
>>>>> MMC_NO_POWER_NOTIFICATION;
>>>>> -       }
>>>>> -       mmc_release_host(host);
>>>>> -}
>>>>> -
>>>>>  /*
>>>>>  * Apply power to the MMC stack.  This is a two-stage process.
>>>>>  * First, we enable power to the card without the clock running.
>>>>> @@ -1198,30 +1156,12 @@ static void mmc_power_up(struct mmc_host *host)
>>>>>
>>>>>  void mmc_power_off(struct mmc_host *host)
>>>>>  {
>>>>> -       int err = 0;
>>>>>        mmc_host_clk_hold(host);
>>>>>
>>>>>        host->ios.clock = 0;
>>>>>        host->ios.vdd = 0;
>>>>>
>>>>>        /*
>>>>> -        * For eMMC 4.5 device send AWAKE command before
>>>>> -        * POWER_OFF_NOTIFY command, because in sleep state
>>>>> -        * eMMC 4.5 devices respond to only RESET and AWAKE cmd
>>>>> -        */
>>>>> -       if (host->card&&   mmc_card_is_sleep(host->card)&&
>>>>> -           host->bus_ops->resume) {
>>>>> -               err = host->bus_ops->resume(host);
>>>>> -
>>>>> -               if (!err)
>>>>> -                       mmc_poweroff_notify(host);
>>>>> -               else
>>>>> -                       pr_warning("%s: error %d during resume "
>>>>> -                                  "(continue with poweroff
>>>>> sequence)\n",
>>>>> -                                  mmc_hostname(host), err);
>>>>> -       }
>>>>> -
>>>>> -       /*
>>>>>         * Reset ocr mask to be the highest possible voltage supported
>>>>> for
>>>>>         * this mmc host. This value will be used at next power up.
>>>>>         */
>>>>> @@ -2084,6 +2024,9 @@ void mmc_stop_host(struct mmc_host *host)
>>>>>
>>>>>        mmc_bus_get(host);
>>>>>        if (host->bus_ops&&   !host->bus_dead) {
>>>>>
>>>>> +               if (host->bus_ops->poweroff_notify)
>>>>> +                       host->bus_ops->poweroff_notify(host);
>>>>> +
>>>>>                /* Calling bus_ops->remove() with a claimed host can
>>>>> deadlock */
>>>>>                if (host->bus_ops->remove)
>>>>>                        host->bus_ops->remove(host);
>>>>> @@ -2093,6 +2036,7 @@ void mmc_stop_host(struct mmc_host *host)
>>>>>                mmc_power_off(host);
>>>>>                mmc_release_host(host);
>>>>>                mmc_bus_put(host);
>>>>> +
>>>>>                return;
>>>>>        }
>>>>>        mmc_bus_put(host);
>>>>> @@ -2119,7 +2063,9 @@ int mmc_power_save_host(struct mmc_host *host)
>>>>>
>>>>>        if (host->bus_ops->power_save)
>>>>>                ret = host->bus_ops->power_save(host);
>>>>> -
>>>>> +       host->power_notify_type = MMC_HOST_PW_NOTIFY_SHORT;
>>>>> +       if (host->bus_ops->poweroff_notify)
>>>>> +               host->bus_ops->poweroff_notify(host);
>>>>>        mmc_bus_put(host);
>>>>>
>>>>>        mmc_power_off(host);
>>>>> @@ -2142,7 +2088,7 @@ int mmc_power_restore_host(struct mmc_host *host)
>>>>>                mmc_bus_put(host);
>>>>>                return -EINVAL;
>>>>>        }
>>>>> -
>>>>> +       host->power_notify_type = MMC_HOST_PW_NOTIFY_LONG;
>>>>>        mmc_power_up(host);
>>>>>        ret = host->bus_ops->power_restore(host);
>>>>>
>>>>> @@ -2161,8 +2107,11 @@ int mmc_card_awake(struct mmc_host *host)
>>>>>
>>>>>        mmc_bus_get(host);
>>>>>
>>>>> -       if (host->bus_ops&&   !host->bus_dead&&   host->bus_ops->awake)
>>>>> +       if (host->bus_ops&&   !host->bus_dead&&   host->bus_ops->awake)
>>>>> {
>>>>>
>>>>>                err = host->bus_ops->awake(host);
>>>>> +               if (!err)
>>>>> +                       mmc_card_clr_sleep(host->card);
>>>>> +       }
>>>>>
>>>>>        mmc_bus_put(host);
>>>>>
>>>>> @@ -2179,8 +2128,11 @@ int mmc_card_sleep(struct mmc_host *host)
>>>>>
>>>>>        mmc_bus_get(host);
>>>>>
>>>>> -       if (host->bus_ops&&   !host->bus_dead&&   host->bus_ops->sleep)
>>>>> +       if (host->bus_ops&&   !host->bus_dead&&   host->bus_ops->sleep)
>>>>> {
>>>>>
>>>>>                err = host->bus_ops->sleep(host);
>>>>> +               if (!err)
>>>>> +                       mmc_card_set_sleep(host->card);
>>>>> +       }
>>>>>
>>>>>        mmc_bus_put(host);
>>>>>
>>>>> @@ -2394,6 +2346,8 @@ int mmc_pm_notify(struct notifier_block
>>>>> *notify_block,
>>>>>
>>>>>                if (!host->bus_ops || host->bus_ops->suspend)
>>>>>                        break;
>>>>> +               if (host->bus_ops->poweroff_notify)
>>>>> +                       host->bus_ops->poweroff_notify(host);
>>>>>
>>>>>                /* Calling bus_ops->remove() with a claimed host can
>>>>> deadlock */
>>>>>                if (host->bus_ops->remove)
>>>>> @@ -2403,6 +2357,7 @@ int mmc_pm_notify(struct notifier_block
>>>>> *notify_block,
>>>>>                mmc_detach_bus(host);
>>>>>                mmc_power_off(host);
>>>>>                mmc_release_host(host);
>>>>> +
>>>>>                host->pm_flags = 0;
>>>>>                break;
>>>>>
>>>>> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
>>>>> index 3bdafbc..351cbbe 100644
>>>>> --- a/drivers/mmc/core/core.h
>>>>> +++ b/drivers/mmc/core/core.h
>>>>> @@ -25,6 +25,7 @@ struct mmc_bus_ops {
>>>>>        int (*power_save)(struct mmc_host *);
>>>>>        int (*power_restore)(struct mmc_host *);
>>>>>        int (*alive)(struct mmc_host *);
>>>>> +       int (*poweroff_notify)(struct mmc_host *);
>>>>>  };
>>>>>
>>>>>  void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops
>>>>> *ops);
>>>>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>>>>> index 54df5ad..62bdee6 100644
>>>>> --- a/drivers/mmc/core/mmc.c
>>>>> +++ b/drivers/mmc/core/mmc.c
>>>>> @@ -1282,6 +1282,50 @@ err:
>>>>>        return err;
>>>>>  }
>>>>>
>>>>> +static int mmc_poweroff_notify(struct mmc_host *host)
>>>>> +{
>>>>> +       struct mmc_card *card;
>>>>> +       unsigned int timeout;
>>>>> +       unsigned int notify_type = EXT_CSD_NO_POWER_NOTIFICATION;
>>>>> +       int err = -EINVAL;
>>>
>>>
>>> Should we consider it an error if the card does not support poweroff
>>> notification?
>>
>> To make it more meaningful I will change the error value to -EOPNOTSUPP.
>>>
>>>
>>> Moreover, this function returns an error code which is good. Although
>>> everywhere you call this function you do not consider the error. Please
>>> look
>>> into changing this.
>>
>> Also will consider the return value from the places it is called to
>> display the info "card doesnt support po notify"
>>>
>>>
>>>
>>>>> +
>>>>> +       card = host->card;
>>>>> +       mmc_claim_host(host);
>>>>> +
>>>>> +       /*
>>>>> +        * Send power notify command only if card
>>>>> +        * is mmc and notify state is powered ON
>>>>> +        */
>>>>> +       if (card&&   mmc_card_mmc(card)&&
>>>
>>>
>>> Some white spaces..
>>
>> will rum cleanpatch
>>>
>>>
>>>
>>>>> +           (card->poweroff_notify_state == MMC_POWERED_ON)) {
>>>>> +
>>>>> +               if (host->power_notify_type ==
>>>>> MMC_HOST_PW_NOTIFY_SHORT)
>>>>> {
>>>>> +                       notify_type = EXT_CSD_POWER_OFF_SHORT;
>>>>> +                       timeout = card->ext_csd.generic_cmd6_time;
>>>>> +                       card->poweroff_notify_state =
>>>>> MMC_POWEROFF_SHORT;
>>>>> +               } else {
>>>>> +                       notify_type = EXT_CSD_POWER_OFF_LONG;
>>>>> +                       timeout = card->ext_csd.power_off_longtime;
>>>>> +                       card->poweroff_notify_state =
>>>>> MMC_POWEROFF_LONG;
>>>>> +               }
>>>>> +
>>>>> +               err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>>>>> +                                EXT_CSD_POWER_OFF_NOTIFICATION,
>>>>> +                                notify_type, timeout);
>>>>> +
>>>>> +               if (err&&   err != -EBADMSG)
>>>
>>>
>>> Some white spaces..
>>>
>>>
>>>>> +                       pr_err("%s: Device failed to respond within %d
>>>>> "
>>>>> +                              "poweroff time. Forcefully powering down
>>>>> "
>>>>> +                              "the device\n", mmc_hostname(host),
>>>>> timeout);
>>>>> +
>>>>> +               /* Set the card state to no notification after the
>>>>> poweroff */
>>>>> +               card->poweroff_notify_state =
>>>>> MMC_NO_POWER_NOTIFICATION;
>>>>> +       }
>>>>> +       mmc_release_host(host);
>>>>> +
>>>>> +       return err;
>>>>> +}
>>>>> +
>>>>>  /*
>>>>>  * Host is being removed. Free up the current card.
>>>>>  */
>>>>> @@ -1341,15 +1385,20 @@ static int mmc_suspend(struct mmc_host *host)
>>>>>        BUG_ON(!host);
>>>>>        BUG_ON(!host->card);
>>>>>
>>>>> -       mmc_claim_host(host);
>>>
>>>
>>> nested claims is OK, so you can keep this if the code becomes easier to
>>> read!? The corresponding mmc_release_host then as well of course...
>>>
>>>>> -       if (mmc_card_can_sleep(host)) {
>>>>> -               err = mmc_card_sleep(host);
>>>>> -               if (!err)
>>>>> -                       mmc_card_set_sleep(host->card);
>>>>> -       } else if (!mmc_host_is_spi(host))
>>>>> -               mmc_deselect_cards(host);
>>>>> -       host->card->state&= ~(MMC_STATE_HIGHSPEED |
>>>>> MMC_STATE_HIGHSPEED_200);
>>>>>
>>>>> -       mmc_release_host(host);
>>>>> +       if (host->caps2&   MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND) {
>>>
>>>
>>> Some white spaces..
>>>
>>> This will not work. If the card does not support "poweroff_notify", but
>>> sleep, then the card will not be put to sleep. The cap should not be used
>>> to
>>> determine what the card supports, only the host.
>>
>> I will remove th host caps option. and directly call the power off
>> notify function. This function will execute the switch command only if
>> the card supports the power off notify.
>> so comparison with host caps can be omitted.
>
>
> I don't think removing the host cap i a good option. If the host only
> supports removing VCC and not VCCQ, we would like to issue the sleep cmd in
> favor of poweroff_notify cmd. Both conditions must thus be checked.
>
> Thus I think a "mmc_card_can_poweroff_notify" could be feasible to use here
> for simplifying things.
>

If host does not remove VCCQ, then it will not enable
MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND. I agree that we need to have
an additional check just to ensure that we wrongly do not issue power
Off notify on 4.41 eMMC. We can do something like,

static int mmc_suspend(struct mmc_host *host)
{
...
	card = host->card;

	if (card && mmc_card_mmc(card) &&
	    (card->poweroff_notify_state == MMC_POWERED_ON) &&
	    (host->caps2 & MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND) {
		err = mmc_poweroff_notify(host);
	} else {
        ....
        }
 ....
 }

Girish, I still like to have this host cap.

>
>
>>>
>>> Maybe an new function "mmc_card_can_poweroff_notify" can help out in
>>> taking
>>> the right decision here. The you also might be able to get rid of the
>>> host->poweroff_notify_state variable, don't know.
>>
>> not necessary to add a new function as said above the notify function
>> takes care of card support
>>>
>>>
>>>
>>>>> +               err = mmc_poweroff_notify(host);
>>>>> +       } else {
>>>>> +               mmc_claim_host(host);
>>>>> +               if (mmc_card_can_sleep(host))
>>>>> +                       err = mmc_card_sleep(host);
>>>>> +               else if (!mmc_host_is_spi(host))
>>>>> +                       mmc_deselect_cards(host);
>>>>> +               mmc_release_host(host);
>>>>> +       }
>>>>> +
>>>>> +       if (!err)
>>>>> +               host->card->state&=
>>>>> +                       ~(MMC_STATE_HIGHSPEED |
>>>>> MMC_STATE_HIGHSPEED_200);
>>>>>
>>>>>        return err;
>>>>>  }
>>>>> @@ -1368,11 +1417,11 @@ static int mmc_resume(struct mmc_host *host)
>>>>>        BUG_ON(!host->card);
>>>>>
>>>>>        mmc_claim_host(host);
>>>>> -       if (mmc_card_is_sleep(host->card)) {
>>>>> +       if (mmc_card_is_sleep(host->card))
>>>>>                err = mmc_card_awake(host);
>>>>> -               mmc_card_clr_sleep(host->card);
>>>>> -       } else
>>>>> +       else
>>>>>                err = mmc_init_card(host, host->ocr, host->card);
>>>>> +
>>>>>        mmc_release_host(host);
>>>>>
>>>>>        return err;
>>>>> @@ -1430,6 +1479,7 @@ static const struct mmc_bus_ops mmc_ops = {
>>>>>        .resume = NULL,
>>>>>        .power_restore = mmc_power_restore,
>>>>>        .alive = mmc_alive,
>>>>> +       .poweroff_notify = NULL,
>>>
>>>
>>> Is there any problems with adding the function here? Even if an eMMC
>>> always
>>> should be considered non-removable, and thus the unsafe bus_ops should be
>>> used. I don't know the reason to why sleep/awake has been added to this
>>> bus_ops, but I think poweroff_notify should be handled similarly...
>>
>> No problem in adding. The only reason for not adding is that none of
>> the removable cards support poweroff notify. this feature is supported
>> above 4.5 version. If you have come across any 4.5 removable device,
>> it would more convinient to add here.
>
>
> For testing I believe 4.5 eMMC in an SD-card adapter can be used. But just
> for testing...
>
>
>>>
>>>
>>>>>  };
>>>>>
>>>>>  static const struct mmc_bus_ops mmc_ops_unsafe = {
>>>>> @@ -1441,6 +1491,7 @@ static const struct mmc_bus_ops mmc_ops_unsafe =
>>>>> {
>>>>>        .resume = mmc_resume,
>>>>>        .power_restore = mmc_power_restore,
>>>>>        .alive = mmc_alive,
>>>>> +       .poweroff_notify = mmc_poweroff_notify,
>>>>>  };
>>>>>
>>>>>  static void mmc_attach_bus_ops(struct mmc_host *host)
>>>>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>>>>> index cbde4b7..cf44a6f 100644
>>>>> --- a/include/linux/mmc/host.h
>>>>> +++ b/include/linux/mmc/host.h
>>>>> @@ -238,6 +238,7 @@ struct mmc_host {
>>>>>  #define MMC_CAP2_BROKEN_VOLTAGE        (1<<   7)        /* Use the
>>>>> broken
>>>>> voltage */
>>>>>  #define MMC_CAP2_DETECT_ON_ERR (1<<   8)        /* On I/O err check
>>>>> card
>>>>> removal */
>>>>>  #define MMC_CAP2_HC_ERASE_SZ   (1<<   9)        /* High-capacity erase
>>>>> size */
>>>>> +#define MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND (1<<   10)
>>>
>>>
>>> Don't know if we would like to use the old caps(1) bit 7, since
>>> MMC_CAP_DISABLE has been removed and thus this bit is now available...
>>
>> I am planning to remove this caps.
>>>
>>>
>>>
>>>>>
>>>>>        mmc_pm_flag_t           pm_caps;        /* supported pm features
>>>>> */
>>>>>        unsigned int        power_notify_type;
>>>>
>>>>
>>>>
>>>> Hi Ulf,
>>>> need your comment on the above.
>>>>>
>>>>>
>>>>> --
>>>>> 1.7.1
>>>>>
>>>
>>> Overall, I like this patch, we are getting close to a final version I
>>> think.
>>>
>>> Kind regards
>>> Ulf Hansson
>
>
> Kind regards
> Ulf Hansson