Re: [RFC/PATCH] mmc: core: Signal wakeup event at card insert/removal

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Ulf,

On 09/20/2013 06:48 PM, Ulf Hansson wrote:
> We want to give user space provision to fully consume a card
> insert/remove event, when the event was caused by a wakeup irq.
> 
> By signaling the wakeup event for a time of 5 s for devices configured
> as wakeup capable, we likely will be prevent a sleep long enough to let
> user space consume the event.
> 
> To enable this feature, host drivers must thus configure their devices
> as wakeup capable.
> 
> This is a reworked implementation of the old wakelocks for the mmc
> subsystem, originally authored by Colin Cross and San Mehat for the
> Android kernel. Zoran Markovic shall also be given cred for recently
> re-trying to upstream this feature.
> 
> Cc: San Mehat <san@google.com>
> Cc: Colin Cross <ccross@android.com>
> Cc: John Stultz <john.stultz@linaro.org>
> Cc: Zoran Markovic <zoran.markovic@linaro.org>
> Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
> ---
> 
> This patch has just been compile tested, since I at very moment did not
> have a good board to test it on. I am working on that.
> 
> Any help in testing this patch is thus greatly appreciated. While
> testing also don't forget to enable the host device as wakeup capable.
> Use "device_init_wakeup" from the host probe function.

I used the device_init_wakeup(&pdev->dev, 1) into host controller. (Also enabled the irq for wakeup)
It didn't work when device is suspended.
Well, i might missed something.
As my understanding, it's helpful that wakeup-event is used when device is suspended.
How do you call mmc_detect_change() during suspended?

Best Regards,
Jaehoon Chung
> 
> ---
>  drivers/mmc/core/core.c |   39 +++++++++++++++++++++++++++------------
>  1 file changed, 27 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index bf18b6b..3e8229e 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -23,6 +23,7 @@
>  #include <linux/log2.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/pm_wakeup.h>
>  #include <linux/suspend.h>
>  #include <linux/fault-inject.h>
>  #include <linux/random.h>
> @@ -1723,6 +1724,28 @@ void mmc_detach_bus(struct mmc_host *host)
>  	mmc_bus_put(host);
>  }
>  
> +static void _mmc_detect_change(struct mmc_host *host, unsigned long delay,
> +				bool cd_irq)
> +{
> +#ifdef CONFIG_MMC_DEBUG
> +	unsigned long flags;
> +	spin_lock_irqsave(&host->lock, flags);
> +	WARN_ON(host->removed);
> +	spin_unlock_irqrestore(&host->lock, flags);
> +#endif
> +
> +	/*
> +	 * If the device is configured as wakeup, we prevent a new sleep for
> +	 * 5 s to give provision for user space to consume the event.
> +	 */
> +	if (cd_irq && !(host->caps & MMC_CAP_NEEDS_POLL) &&
> +		device_can_wakeup(mmc_dev(host)))
> +		pm_wakeup_event(mmc_dev(host), 5000);
> +
> +	host->detect_change = 1;
> +	mmc_schedule_delayed_work(&host->detect, delay);
> +}
> +
>  /**
>   *	mmc_detect_change - process change of state on a MMC socket
>   *	@host: host which changed state.
> @@ -1735,16 +1758,8 @@ void mmc_detach_bus(struct mmc_host *host)
>   */
>  void mmc_detect_change(struct mmc_host *host, unsigned long delay)
>  {
> -#ifdef CONFIG_MMC_DEBUG
> -	unsigned long flags;
> -	spin_lock_irqsave(&host->lock, flags);
> -	WARN_ON(host->removed);
> -	spin_unlock_irqrestore(&host->lock, flags);
> -#endif
> -	host->detect_change = 1;
> -	mmc_schedule_delayed_work(&host->detect, delay);
> +	_mmc_detect_change(host, delay, true);
>  }
> -
>  EXPORT_SYMBOL(mmc_detect_change);
>  
>  void mmc_init_erase(struct mmc_card *card)
> @@ -2423,7 +2438,7 @@ int mmc_detect_card_removed(struct mmc_host *host)
>  			 * rescan handle the card removal.
>  			 */
>  			cancel_delayed_work(&host->detect);
> -			mmc_detect_change(host, 0);
> +			_mmc_detect_change(host, 0, false);
>  		}
>  	}
>  
> @@ -2505,7 +2520,7 @@ void mmc_start_host(struct mmc_host *host)
>  		mmc_power_off(host);
>  	else
>  		mmc_power_up(host);
> -	mmc_detect_change(host, 0);
> +	_mmc_detect_change(host, 0, false);
>  }
>  
>  void mmc_stop_host(struct mmc_host *host)
> @@ -2724,7 +2739,7 @@ int mmc_pm_notify(struct notifier_block *notify_block,
>  		spin_lock_irqsave(&host->lock, flags);
>  		host->rescan_disable = 0;
>  		spin_unlock_irqrestore(&host->lock, flags);
> -		mmc_detect_change(host, 0);
> +		_mmc_detect_change(host, 0, false);
>  
>  	}
>  
>