On 30 April 2012 18:39, Subhash Jadavani <subhashj@xxxxxxxxxxxxxx> wrote:
> On 4/30/2012 11:44 AM, Girish K S 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.
>
> What the specification mandates? Does it expect the host to turn off both
> VCC and VCCQ rails after power off notification (short/long)? What if we
> send the power off notification (short/long) but still don't turn off either
> VCCQ or VCC or both?
>
The specification does not say that the power OFF notify has to be
followed by switching off Vcc and Vccq. We however reinitialize eMMC
before using it again.
>>
>> 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.
>>
>> Signed-off-by: Saugata Das<saugata.das@xxxxxxxxxx>
>> Signed-off-by: Girish K S<girish.shivananjappa@xxxxxxxxxx>
>> ---
>> drivers/mmc/core/core.c | 95
>> +++++++++++++++------------------------------
>> drivers/mmc/core/core.h | 1 +
>> drivers/mmc/core/mmc.c | 76 +++++++++++++++++++++++++++++++------
>> include/linux/mmc/host.h | 1 +
>> 4 files changed, 98 insertions(+), 75 deletions(-)
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index ba821fe..7f5461e 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 +2024,14 @@ 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) {
>> + int err = host->bus_ops->poweroff_notify(host);
>> + if (err)
>> + pr_info("%s: error [%x] in poweroff
>> notify\n",
>> + mmc_hostname(host), err);
>> + }
>> +
>> /* Calling bus_ops->remove() with a claimed host can
>> deadlock */
>> if (host->bus_ops->remove)
>> host->bus_ops->remove(host);
>> @@ -2093,6 +2041,7 @@ 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);
>> @@ -2119,6 +2068,13 @@ 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) {
>> + int err = host->bus_ops->poweroff_notify(host);
>> + if (err)
>> + pr_info("%s: error [%x] in poweroff notify\n",
>> + mmc_hostname(host), err);
>> + }
>>
>> mmc_bus_put(host);
>>
>> @@ -2142,7 +2098,7 @@ int mmc_power_restore_host(struct mmc_host *host)
>> mmc_bus_put(host);
>> return -EINVAL;
>> }
>> -
>> + host->power_notify_type = MMC_HOST_PW_NOTIFY_LONG;
>
> why are we setting the notify_type to NOTIFY_LONG here? Isn't this a resume?
>>
>> mmc_power_up(host);
>> ret = host->bus_ops->power_restore(host);
>>
>> @@ -2161,8 +2117,11 @@ 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 +2138,11 @@ 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);
>>
>> @@ -2379,6 +2341,12 @@ int mmc_pm_notify(struct notifier_block
>> *notify_block,
>>
>> if (!host->bus_ops || host->bus_ops->suspend)
>> break;
>> + if (host->bus_ops->poweroff_notify) {
>> + int err = host->bus_ops->poweroff_notify(host);
>> + if (err)
>> + pr_info("%s: error [%x] in poweroff
>> notify\n",
>> + mmc_hostname(host), err);
>
> err is printed in hex format? shouldn't it be %d ? Also can we move this
> message printing with in poweroff_notify() function before returning from
> it?
>
>> + }
>>
>> /* Calling bus_ops->remove() with a claimed host can
>> deadlock */
>> if (host->bus_ops->remove)
>> @@ -2388,6 +2356,7 @@ int mmc_pm_notify(struct notifier_block
>> *notify_block,
>> mmc_detach_bus(host);
>> mmc_power_off(host);
>> mmc_release_host(host);
>> +
>
> why is this extra line space added?
>
>> 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..11ab536 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 = -EOPNOTSUPP;
>> +
>> + card = host->card;
>> + mmc_claim_host(host);
>
> Shouldn't we really claim_host() when we are about to send command to card?
> Currently claim_host() is called even if card=NULL or poweroff_notify_state
> is already short/long.
> Actually if possible we should force the caller of this function to check if
> it's MMC card or not and they should only call this function if it's MMC
> card.
>
> Basically if this function is called with card=NULL or card_type!=MMC, this
> function should not return an error because caller of this function is
> printing pr_info() message in case of an error.
>
>
>> +
>> + /*
>> + * 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) {
>
> shouldn't the name should be "poweroff_notify_type" to be consisten with
> other variables like "poweroff_notify_state"? even MMC_HOST_PW_NOTIFY_SHORT
> should be named as MMC_HOST_PW_OFF_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;.
>
> I don't see need of these 2 extra states (MMC_POWEROFF_SHORT and
> MMC_POWEROFF_SHORT).
> MMC_POWERED_ON and MMC_NO_POWER_NOTIFICATION should be enough.
>
> Basically if state is MMC_POWERED_ON, we can send the short/long power off
> notification. And if state is MMC_NO_POWER_NOTIFICATION, we can't send the
> short/long power off notification.
>>
>> + }
>> +
>> + err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
>> + EXT_CSD_POWER_OFF_NOTIFICATION,
>> + notify_type, timeout);
>> +
>> + if (err&& err != -EBADMSG)
>>
>> + 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;
>
> poweroff_notify_state should be set to MMC_NO_POWER_NOTIFICATION only if
> mmc_switch() command is successful or else it's state should remain
> MMC_POWERED_ON.
> Also, Shouldn't we set the poweroff_notify_state to MMC_NO_POWER_NOTIFICTION
> in mmc_init_card() if mmc_switch() returns error?
>>
>> + }
>> + mmc_release_host(host);
>> +
>> + return err;
>> +}
>> +
>> /*
>> * Host is being removed. Free up the current card.
>> */
>> @@ -1341,15 +1385,21 @@ static int mmc_suspend(struct mmc_host *host)
>> BUG_ON(!host);
>> BUG_ON(!host->card);
>>
>> - mmc_claim_host(host);
>> - 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->card)&& mmc_card_mmc(host->card)&&
>> + (host->caps2& MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND)) {
>> + err = mmc_poweroff_notify(host);
>
> can't we invoke the power_off_notify bus ops instead of calling
> mmc_poweroff_notify() directly ?
>
>> + } 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 +1418,11 @@ 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 +1480,7 @@ static const struct mmc_bus_ops mmc_ops = {
>> .resume = NULL,
>> .power_restore = mmc_power_restore,
>> .alive = mmc_alive,
>> + .poweroff_notify = mmc_poweroff_notify,
>> };
>>
>> static const struct mmc_bus_ops mmc_ops_unsafe = {
>> @@ -1441,6 +1492,7 @@ 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 0707d22..986e22b 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)
>>
>> mmc_pm_flag_t pm_caps; /* supported pm features */
>> unsigned int power_notify_type;
>
>
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