Re: [RFC PATCH] mmc: core: Invoke sdio func driver's PM callbacks from the sdio bus

[Aaron Lu]

On 02/28/2014 07:49 PM, Ulf Hansson wrote:
> The sdio func device is added to the driver model after the card
> device.
> 
> This means the sdio func device will be suspend before the card device
> and thus resumed after. The consequence are the mmc core don't
> explicity need to protect itself from receiving sdio requests in
> suspended state. Instead that can be handled from the sdio bus, which
> is thus invokes the PM callbacks instead of old dummy function.
> 
> In the case were the sdio func driver don't implement the PM callbacks
> the mmc core will in the early phase of system suspend, remove the
> card from the driver model and thus power off it.
> 
> Cc: Aaron Lu <aaron.lu@xxxxxxxxx>
> Cc: NeilBrown <neilb@xxxxxxx>
> Cc: Rafael J. Wysocki <rjw@xxxxxxxxxxxxx>
> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> ---
> 
> Note, this patch has only been compile tested. Would appreciate if some with
> SDIO and a sdio func driver could help out to test this. Especially the
> libertas driver would be nice.
> 
> ---
>  drivers/mmc/core/sdio.c     |   45 ++++---------------------------------------
>  drivers/mmc/core/sdio_bus.c |   14 +-------------
>  2 files changed, 5 insertions(+), 54 deletions(-)
> 
> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
> index 4d721c6..9933e42 100644
> --- a/drivers/mmc/core/sdio.c
> +++ b/drivers/mmc/core/sdio.c
> @@ -943,40 +943,21 @@ static int mmc_sdio_pre_suspend(struct mmc_host *host)
>   */
>  static int mmc_sdio_suspend(struct mmc_host *host)
>  {
> -	int i, err = 0;
> -
> -	for (i = 0; i < host->card->sdio_funcs; i++) {
> -		struct sdio_func *func = host->card->sdio_func[i];
> -		if (func && sdio_func_present(func) && func->dev.driver) {
> -			const struct dev_pm_ops *pmops = func->dev.driver->pm;
> -			err = pmops->suspend(&func->dev);
> -			if (err)
> -				break;
> -		}
> -	}
> -	while (err && --i >= 0) {
> -		struct sdio_func *func = host->card->sdio_func[i];
> -		if (func && sdio_func_present(func) && func->dev.driver) {
> -			const struct dev_pm_ops *pmops = func->dev.driver->pm;
> -			pmops->resume(&func->dev);
> -		}
> -	}
> -
> -	if (!err && mmc_card_keep_power(host) && mmc_card_wake_sdio_irq(host)) {
> +	if (mmc_card_keep_power(host) && mmc_card_wake_sdio_irq(host)) {
>  		mmc_claim_host(host);
>  		sdio_disable_wide(host->card);
>  		mmc_release_host(host);
>  	}
>  
> -	if (!err && !mmc_card_keep_power(host))
> +	if (!mmc_card_keep_power(host))
>  		mmc_power_off(host);
>  
> -	return err;
> +	return 0;
>  }
>  
>  static int mmc_sdio_resume(struct mmc_host *host)
>  {
> -	int i, err = 0;
> +	int err = 0;
>  
>  	BUG_ON(!host);
>  	BUG_ON(!host->card);
> @@ -1019,24 +1000,6 @@ static int mmc_sdio_resume(struct mmc_host *host)
>  		wake_up_process(host->sdio_irq_thread);
>  	mmc_release_host(host);
>  
> -	/*
> -	 * If the card looked to be the same as before suspending, then
> -	 * we proceed to resume all card functions.  If one of them returns
> -	 * an error then we simply return that error to the core and the
> -	 * card will be redetected as new.  It is the responsibility of
> -	 * the function driver to perform further tests with the extra
> -	 * knowledge it has of the card to confirm the card is indeed the
> -	 * same as before suspending (same MAC address for network cards,
> -	 * etc.) and return an error otherwise.
> -	 */
> -	for (i = 0; !err && i < host->card->sdio_funcs; i++) {
> -		struct sdio_func *func = host->card->sdio_func[i];
> -		if (func && sdio_func_present(func) && func->dev.driver) {
> -			const struct dev_pm_ops *pmops = func->dev.driver->pm;
> -			err = pmops->resume(&func->dev);
> -		}
> -	}
> -
>  	host->pm_flags &= ~MMC_PM_KEEP_POWER;
>  	return err;
>  }
> diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
> index 92d1ba8..4fa8fef9 100644
> --- a/drivers/mmc/core/sdio_bus.c
> +++ b/drivers/mmc/core/sdio_bus.c
> @@ -197,20 +197,8 @@ static int sdio_bus_remove(struct device *dev)
>  
>  #ifdef CONFIG_PM
>  
> -#ifdef CONFIG_PM_SLEEP
> -static int pm_no_operation(struct device *dev)
> -{
> -	/*
> -	 * Prevent the PM core from calling SDIO device drivers' suspend
> -	 * callback routines, which it is not supposed to do, by using this
> -	 * empty function as the bus type suspend callaback for SDIO.
> -	 */
> -	return 0;
> -}
> -#endif
> -
>  static const struct dev_pm_ops sdio_bus_pm_ops = {
> -	SET_SYSTEM_SLEEP_PM_OPS(pm_no_operation, pm_no_operation)
> +	SET_SYSTEM_SLEEP_PM_OPS(pm_generic_suspend, pm_generic_resume)

The same thing can be achieved by not defining the two callbacks here,
the PM core will use driver's callback in that case, but that is not a
big deal.

Reviewed-by: Aaron Lu <aaron.lu@xxxxxxxxx>

Thanks,
Aaron

>  	SET_RUNTIME_PM_OPS(
>  		pm_generic_runtime_suspend,
>  		pm_generic_runtime_resume,
> 

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