RE: [PATCH 1/32] mmc: add 'enable' and 'disable' methods to mmc host

["Madhusudhan" <madhu.cr@ti.com>]

Hi Adrian,

The patch numbers 7 and 28 in the series seems to be missing?

Regards,
Madhu

> -----Original Message-----
> From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-
> owner@vger.kernel.org] On Behalf Of Adrian Hunter
> Sent: Friday, July 10, 2009 7:40 AM
> To: Pierre Ossman
> Cc: Jarkko Lavinen; Denis Karpov; Adrian Hunter; linux-omap Mailing List;
> lkml
> Subject: [PATCH 1/32] mmc: add 'enable' and 'disable' methods to mmc host
> 
> From a0164897276e4d1f972fd90b1e9499e1ab8d221e Mon Sep 17 00:00:00 2001
> From: Adrian Hunter <adrian.hunter@nokia.com>
> Date: Wed, 22 Apr 2009 12:50:45 +0300
> Subject: [PATCH] mmc: add 'enable' and 'disable' methods to mmc host
> 
> MMC hosts that support power saving can use the 'enable' and
> 'disable' methods to exit and enter power saving states.
> An explanation of their use is provided in the comments
> added to include/linux/mmc/host.h.
> 
> Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
> ---
>  drivers/mmc/core/core.c  |  174
> ++++++++++++++++++++++++++++++++++++++++++++--
>  drivers/mmc/core/host.c  |    1 +
>  drivers/mmc/core/host.h  |    2 +
>  include/linux/mmc/host.h |   47 ++++++++++++
>  4 files changed, 218 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index d84c880..41fd127 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -344,6 +344,98 @@ unsigned int mmc_align_data_size(struct mmc_card
> *card, unsigned int sz)
>  EXPORT_SYMBOL(mmc_align_data_size);
> 
>  /**
> + *	mmc_host_enable - enable a host.
> + *	@host: mmc host to enable
> + *
> + *	Hosts that support power saving can use the 'enable' and 'disable'
> + *	methods to exit and enter power saving states. For more information
> + *	see comments for struct mmc_host_ops.
> + */
> +int mmc_host_enable(struct mmc_host *host)
> +{
> +	if (!(host->caps & MMC_CAP_DISABLE))
> +		return 0;
> +
> +	if (host->en_dis_recurs)
> +		return 0;
> +
> +	if (host->nesting_cnt++)
> +		return 0;
> +
> +	cancel_delayed_work_sync(&host->disable);
> +
> +	if (host->enabled)
> +		return 0;
> +
> +	if (host->ops->enable) {
> +		int err;
> +
> +		host->en_dis_recurs = 1;
> +		err = host->ops->enable(host);
> +		host->en_dis_recurs = 0;
> +
> +		if (err) {
> +			pr_debug("%s: enable error %d\n",
> +				 mmc_hostname(host), err);
> +			return err;
> +		}
> +	}
> +	host->enabled = 1;
> +	return 0;
> +}
> +EXPORT_SYMBOL(mmc_host_enable);
> +
> +static int mmc_host_do_disable(struct mmc_host *host, int lazy)
> +{
> +	if (host->ops->disable) {
> +		int err;
> +
> +		host->en_dis_recurs = 1;
> +		err = host->ops->disable(host, lazy);
> +		host->en_dis_recurs = 0;
> +
> +		if (err < 0) {
> +			pr_debug("%s: disable error %d\n",
> +				 mmc_hostname(host), err);
> +			return err;
> +		}
> +		if (err > 0)
> +			mmc_schedule_delayed_work(&host->disable, err);
> +	}
> +	host->enabled = 0;
> +	return 0;
> +}
> +
> +/**
> + *	mmc_host_disable - disable a host.
> + *	@host: mmc host to disable
> + *
> + *	Hosts that support power saving can use the 'enable' and 'disable'
> + *	methods to exit and enter power saving states. For more information
> + *	see comments for struct mmc_host_ops.
> + */
> +int mmc_host_disable(struct mmc_host *host)
> +{
> +	int err;
> +
> +	if (!(host->caps & MMC_CAP_DISABLE))
> +		return 0;
> +
> +	if (host->en_dis_recurs)
> +		return 0;
> +
> +	if (--host->nesting_cnt)
> +		return 0;
> +
> +	if (!host->enabled)
> +		return 0;
> +
> +	err = mmc_host_do_disable(host, 0);
> +	return err;
> +}
> +EXPORT_SYMBOL(mmc_host_disable);
> +
> +/**
>   *	__mmc_claim_host - exclusively claim a host
>   *	@host: mmc host to claim
>   *	@abort: whether or not the operation should be aborted
> @@ -379,11 +471,81 @@ int __mmc_claim_host(struct mmc_host *host, atomic_t
> *abort)
>  		wake_up(&host->wq);
>  	spin_unlock_irqrestore(&host->lock, flags);
>  	remove_wait_queue(&host->wq, &wait);
> +	if (!stop)
> +		mmc_host_enable(host);
>  	return stop;
>  }
> 
>  EXPORT_SYMBOL(__mmc_claim_host);
> 
> +static int mmc_try_claim_host(struct mmc_host *host)
> +{
> +	int claimed_host = 0;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&host->lock, flags);
> +	if (!host->claimed) {
> +		host->claimed = 1;
> +		claimed_host = 1;
> +	}
> +	spin_unlock_irqrestore(&host->lock, flags);
> +	return claimed_host;
> +}
> +
> +static void mmc_do_release_host(struct mmc_host *host)
> +{
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&host->lock, flags);
> +	host->claimed = 0;
> +	spin_unlock_irqrestore(&host->lock, flags);
> +
> +	wake_up(&host->wq);
> +}
> +
> +void mmc_host_deeper_disable(struct work_struct *work)
> +{
> +	struct mmc_host *host =
> +		container_of(work, struct mmc_host, disable.work);
> +
> +	/* If the host is claimed then we do not want to disable it anymore
> */
> +	if (!mmc_try_claim_host(host))
> +		return;
> +	mmc_host_do_disable(host, 1);
> +	mmc_do_release_host(host);
> +}
> +
> +/**
> + *	mmc_host_lazy_disable - lazily disable a host.
> + *	@host: mmc host to disable
> + *
> + *	Hosts that support power saving can use the 'enable' and 'disable'
> + *	methods to exit and enter power saving states. For more information
> + *	see comments for struct mmc_host_ops.
> + */
> +int mmc_host_lazy_disable(struct mmc_host *host)
> +{
> +	if (!(host->caps & MMC_CAP_DISABLE))
> +		return 0;
> +
> +	if (host->en_dis_recurs)
> +		return 0;
> +
> +	if (--host->nesting_cnt)
> +		return 0;
> +
> +	if (!host->enabled)
> +		return 0;
> +
> +	if (host->disable_delay) {
> +		mmc_schedule_delayed_work(&host->disable,
> +				msecs_to_jiffies(host->disable_delay));
> +		return 0;
> +	} else
> +		return mmc_host_do_disable(host, 1);
> +}
> +EXPORT_SYMBOL(mmc_host_lazy_disable);
> +
>  /**
>   *	mmc_release_host - release a host
>   *	@host: mmc host to release
> @@ -393,15 +555,11 @@ EXPORT_SYMBOL(__mmc_claim_host);
>   */
>  void mmc_release_host(struct mmc_host *host)
>  {
> -	unsigned long flags;
> -
>  	WARN_ON(!host->claimed);
> 
> -	spin_lock_irqsave(&host->lock, flags);
> -	host->claimed = 0;
> -	spin_unlock_irqrestore(&host->lock, flags);
> +	mmc_host_lazy_disable(host);
> 
> -	wake_up(&host->wq);
> +	mmc_do_release_host(host);
>  }
> 
>  EXPORT_SYMBOL(mmc_release_host);
> @@ -947,6 +1105,8 @@ void mmc_stop_host(struct mmc_host *host)
>  	spin_unlock_irqrestore(&host->lock, flags);
>  #endif
> 
> +	if (host->caps & MMC_CAP_DISABLE)
> +		cancel_delayed_work(&host->disable);
>  	cancel_delayed_work(&host->detect);
>  	mmc_flush_scheduled_work();
> 
> @@ -975,6 +1135,8 @@ void mmc_stop_host(struct mmc_host *host)
>   */
>  int mmc_suspend_host(struct mmc_host *host, pm_message_t state)
>  {
> +	if (host->caps & MMC_CAP_DISABLE)
> +		cancel_delayed_work(&host->disable);
>  	cancel_delayed_work(&host->detect);
>  	mmc_flush_scheduled_work();
> 
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index 5e945e6..a268d12 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -83,6 +83,7 @@ struct mmc_host *mmc_alloc_host(int extra, struct device
> *dev)
>  	spin_lock_init(&host->lock);
>  	init_waitqueue_head(&host->wq);
>  	INIT_DELAYED_WORK(&host->detect, mmc_rescan);
> +	INIT_DELAYED_WORK_DEFERRABLE(&host->disable,
> mmc_host_deeper_disable);
> 
>  	/*
>  	 * By default, hosts do not support SGIO or large requests.
> diff --git a/drivers/mmc/core/host.h b/drivers/mmc/core/host.h
> index c2dc3d2..8c87e11 100644
> --- a/drivers/mmc/core/host.h
> +++ b/drivers/mmc/core/host.h
> @@ -14,5 +14,7 @@
>  int mmc_register_host_class(void);
>  void mmc_unregister_host_class(void);
> 
> +void mmc_host_deeper_disable(struct work_struct *work);
> +
>  #endif
> 
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 3e7615e..583c068 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -51,6 +51,35 @@ struct mmc_ios {
>  };
> 
>  struct mmc_host_ops {
> +	/*
> +	 * Hosts that support power saving can use the 'enable' and
> 'disable'
> +	 * methods to exit and enter power saving states. 'enable' is called
> +	 * when the host is claimed and 'disable' is called (or scheduled
> with
> +	 * a delay) when the host is released. The 'disable' is scheduled if
> +	 * the disable delay set by 'mmc_set_disable_delay()' is non-zero,
> +	 * otherwise 'disable' is called immediately. 'disable' may be
> +	 * scheduled repeatedly, to permit ever greater power saving at the
> +	 * expense of ever greater latency to re-enable. Rescheduling is
> +	 * determined by the return value of the 'disable' method. A
> positive
> +	 * value gives the delay in jiffies.
> +	 *
> +	 * In the case where a host function (like set_ios) may be called
> +	 * with or without the host claimed, enabling and disabling can be
> +	 * done directly and will nest correctly. Call 'mmc_host_enable()'
> and
> +	 * 'mmc_host_lazy_disable()' for this purpose, but note that these
> +	 * functions must be paired.
> +	 *
> +	 * Alternatively, 'mmc_host_enable()' may be paired with
> +	 * 'mmc_host_disable()' which calls 'disable' immediately.  In this
> +	 * case the 'disable' method will be called with 'lazy' set to 0.
> +	 * This is mainly useful for error paths.
> +	 *
> +	 * Because lazy disble may be called from a work queue, the
> 'disable'
> +	 * method must claim the host when 'lazy' != 0, which will work
> +	 * correctly because recursion is detected and handled.
> +	 */
> +	int (*enable)(struct mmc_host *host);
> +	int (*disable)(struct mmc_host *host, int lazy);
>  	void	(*request)(struct mmc_host *host, struct mmc_request *req);
>  	/*
>  	 * Avoid calling these three functions too often or in a "fast
> path",
> @@ -118,6 +147,7 @@ struct mmc_host {
>  #define MMC_CAP_SPI		(1 << 4)	/* Talks only SPI protocols
*/
>  #define MMC_CAP_NEEDS_POLL	(1 << 5)	/* Needs polling for card-
> detection */
>  #define MMC_CAP_8_BIT_DATA	(1 << 6)	/* Can the host do 8 bit
> transfers */
> +#define MMC_CAP_DISABLE		(1 << 7)	/* Can the host be
> disabled */
> 
>  	/* host specific block data */
>  	unsigned int		max_seg_size;	/* see
> blk_queue_max_segment_size */
> @@ -142,6 +172,13 @@ struct mmc_host {
>  	unsigned int		removed:1;	/* host is being removed */
>  #endif
> 
> +	/* Only used with MMC_CAP_DISABLE */
> +	int			enabled;	/* host is enabled */
> +	int			nesting_cnt;	/* "enable" nesting count */
> +	int			en_dis_recurs;	/* detect recursion */
> +	unsigned int		disable_delay;	/* disable delay in msecs
> */
> +	struct delayed_work	disable;	/* disabling work */
> +
>  	struct mmc_card		*card;		/* device attached to this
> host */
> 
>  	wait_queue_head_t	wq;
> @@ -197,5 +234,15 @@ struct regulator;
>  int mmc_regulator_get_ocrmask(struct regulator *supply);
>  int mmc_regulator_set_ocr(struct regulator *supply, unsigned short
> vdd_bit);
> 
> +int mmc_host_enable(struct mmc_host *host);
> +int mmc_host_disable(struct mmc_host *host);
> +int mmc_host_lazy_disable(struct mmc_host *host);
> +
> +static inline void mmc_set_disable_delay(struct mmc_host *host,
> +					 unsigned int disable_delay)
> +{
> +	host->disable_delay = disable_delay;
> +}
> +
>  #endif
> 
> --
> 1.5.6.3
> 
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