On 4 April 2012 17:03, Ulf Hansson <ulf.hansson@xxxxxxxxxxxxxx> wrote:
> On 03/30/2012 12:02 PM, 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.
>>
>> 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).
>>
>> Signed-off-by: Saugata Das<saugata.das@xxxxxxxxxx>
>> Signed-off-by: Girish K S<girish.shivananjappa@xxxxxxxxxx>
>> ---
>> drivers/mmc/core/core.c | 36 ++++++++++++++----------------------
>> drivers/mmc/core/core.h | 1 +
>> drivers/mmc/core/mmc.c | 20 +++++++++++++-------
>> include/linux/mmc/host.h | 1 +
>> 4 files changed, 29 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index 14f262e..dc85ee1 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -1096,12 +1096,12 @@ 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)
>> +int mmc_poweroff_notify(struct mmc_host *host)
>
>
> A more generic comment; why is not this function implemented as a bus_ops
> function, similar how sleep for mmc is done? That would be more preferred I
> think.
>
I have nothing for or against the idea. We just wanted to limit the
changes in the patch. In this patch lets focus on the functional
aspects of the power off notify and we can work on moving this
function to bus_ops in a separate patch later.
>
>> {
>> struct mmc_card *card;
>> unsigned int timeout;
>> unsigned int notify_type = EXT_CSD_NO_POWER_NOTIFICATION;
>> - int err = 0;
>> + int err = -EINVAL;
>>
>> card = host->card;
>> mmc_claim_host(host);
>> @@ -1136,6 +1136,7 @@ static void mmc_poweroff_notify(struct mmc_host
>> *host)
>> card->poweroff_notify_state = MMC_NO_POWER_NOTIFICATION;
>> }
>> mmc_release_host(host);
>> + return err;
>> }
>>
>> /*
>> @@ -1194,30 +1195,12 @@ 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.
>> */
>> @@ -2076,6 +2059,7 @@ void mmc_stop_host(struct mmc_host *host)
>> host->pm_flags = 0;
>>
>> mmc_bus_get(host);
>> + mmc_poweroff_notify(host);
>
>
> We must not do mmc_poweroff_notify, without knowing we have a card attached
> through the bus_ops.
>
>> if (host->bus_ops&& !host->bus_dead) {
>>
>> /* Calling bus_ops->remove() with a claimed host can
>> deadlock */
>> if (host->bus_ops->remove)
>> @@ -2112,7 +2096,8 @@ 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;
>> + mmc_poweroff_notify(host);
>
>
> Same comment as above.
>
> Moreover, mmc_power_save_host is not working for eMMC cards supporting the
> SLEEP command (violating the eMMC spec for how VCC is cut). So, I am not
> sure we should introduce the poweroff_notify for the mmc_power_save_host
> right now. Better to fix SLEEP first, if needed at all.
>
> Additionally, this function is only used for SDIO if runtime PM is enabled
> at the moment.
>
>
>> mmc_bus_put(host);
>>
>> mmc_power_off(host);
>> @@ -2135,7 +2120,7 @@ int mmc_power_restore_host(struct mmc_host *host)
>> mmc_bus_put(host);
>> return -EINVAL;
>> }
>> -
>> + host->power_notify_type = MMC_HOST_PW_NOTIFY_LONG;
>
>
> Similar comments as for mmc_power_save_host
>
>> mmc_power_up(host);
>> ret = host->bus_ops->power_restore(host);
>>
>> @@ -2157,6 +2142,9 @@ int mmc_card_awake(struct mmc_host *host)
>> 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);
>> +
>
>
> This code must be handled from withing the bus_ops function instead, or you
> need to move it inside the "if" above, since the awake bus_ops only exist
> for (e)MMC. Moreover, you do not want to set the sleep state unless the
> sleep cmd really has been executed.
>
>> mmc_bus_put(host);
>>
>> return err;
>> @@ -2175,6 +2163,9 @@ int mmc_card_sleep(struct mmc_host *host)
>> 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);
>> +
>
>
> I think this code should be handled from withing the bus_ops function
> instead, or you need to move it inside the "if" above, since the awake
> bus_ops only exist for (e)MMC.
>
>
>> mmc_bus_put(host);
>>
>> return err;
>> @@ -2393,6 +2384,7 @@ int mmc_pm_notify(struct notifier_block
>> *notify_block,
>> host->bus_ops->remove(host);
>>
>> mmc_claim_host(host);
>> + mmc_poweroff_notify(host);
>
>
> This wont work if the card has been removed from the bus_ops->remove above.
>
>
>> mmc_detach_bus(host);
>> mmc_power_off(host);
>> mmc_release_host(host);
>> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
>> index 3bdafbc..0bdc0fd 100644
>> --- a/drivers/mmc/core/core.h
>> +++ b/drivers/mmc/core/core.h
>> @@ -45,6 +45,7 @@ int mmc_set_signal_voltage(struct mmc_host *host, int
>> signal_voltage,
>> void mmc_set_timing(struct mmc_host *host, unsigned int timing);
>> void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type);
>> void mmc_power_off(struct mmc_host *host);
>> +int mmc_poweroff_notify(struct mmc_host *host);
>>
>> static inline void mmc_delay(unsigned int ms)
>> {
>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>> index 02914d6..885ad61 100644
>> --- a/drivers/mmc/core/mmc.c
>> +++ b/drivers/mmc/core/mmc.c
>> @@ -1338,12 +1338,18 @@ static int mmc_suspend(struct mmc_host *host)
>> BUG_ON(!host->card);
>>
>> mmc_claim_host(host);
>> - if (mmc_card_can_sleep(host)) {
>> - err = mmc_card_sleep(host);
>> + if (host->caps2& MMC_CAP2_POWER_OFF_VCCQ_DURING_SUSPEND) {
>
> 1. missing whitespace after caps2
> 2. Can't we have an mmc_card_can_poweroff_notify to check instead, which
> also considering this new cap together with the card features.
The test of capability of the device is done inside the function
mmc_poweroff_notify, which is invoked from different places. It is not
needed to have additional capability check within this "if" condition.
>
>> + err = mmc_poweroff_notify(host);
>> if (!err)
>> - mmc_card_set_sleep(host->card);
>> - } else if (!mmc_host_is_spi(host))
>> + goto out;
>
> Suggest to remove the goto and just have another if-else, as we already have
> for sleep.
>>
>> + }
>> +
>> + if (mmc_card_can_sleep(host))
>> + err = mmc_card_sleep(host);
>> + else if (!mmc_host_is_spi(host))
>> mmc_deselect_cards(host);
>> +
>> +out:
>> host->card->state&= ~(MMC_STATE_HIGHSPEED |
>> MMC_STATE_HIGHSPEED_200);
>>
>> mmc_release_host(host);
>>
>> @@ -1364,11 +1370,11 @@ 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;
>> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
>> index 33a4d08..3749a42 100644
>> --- a/include/linux/mmc/host.h
>> +++ b/include/linux/mmc/host.h
>> @@ -237,6 +237,7 @@ 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;
>
>
> Kind regards
> Ulf Hansson
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