RE: [PATCH V2] mmc: core: Add option to prevent eMMC sleep command

["Subhash Jadavani" <subhashj@codeaurora.org>]

> -----Original Message-----
> From: linux-mmc-owner@vger.kernel.org [mailto:linux-mmc-
> owner@vger.kernel.org] On Behalf Of Ulf Hansson
> Sent: Thursday, December 15, 2011 3:06 PM
> To: linux-mmc@vger.kernel.org; Chris Ball
> Cc: Per Forlin; Ulf Hansson; Johan Rudholm; Lee Jones
> Subject: [PATCH V2] mmc: core: Add option to prevent eMMC sleep command
> 
> Host may now use MMC_CAP2_NOSLEEP to disable the use of
> eMMC sleep/awake command.
> 
> This option can be used when you platform have a buggy
> kernel crash dump software, which is supposed to store
> the dump on the eMMC, but is not able to wake up the eMMC
> from sleep state.
> 
> Signed-off-by: Ulf Hansson <ulf.hansson@stericsson.com>
> Reviewed-by: Hanumath Prasad <hanumath.prasad@stericsson.com>
> Reviewed-by: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com>
> ---
> 
> Changes in v2:
> 	- Added some motivation to why this patch is wanted in the
> 	commit message.
> 
> ---
>  drivers/mmc/core/core.c  |    6 ++++++
>  include/linux/mmc/host.h |    1 +
>  2 files changed, 7 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index a2aa860..5a1ce37 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2246,6 +2246,9 @@ int mmc_card_awake(struct mmc_host *host)
>  {
>  	int err = -ENOSYS;
> 
> +	if (host->caps2 & MMC_CAP2_NOSLEEP)
> +		return 0;
> +
>  	mmc_bus_get(host);
> 
>  	if (host->bus_ops && !host->bus_dead && host->bus_ops->awake)
> @@ -2261,6 +2264,9 @@ int mmc_card_sleep(struct mmc_host *host)
>  {
>  	int err = -ENOSYS;
> 
> +	if (host->caps2 & MMC_CAP2_NOSLEEP)
> +		return 0;
> +
>  	mmc_bus_get(host);
> 
>  	if (host->bus_ops && !host->bus_dead && host->bus_ops->sleep)
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 9a03d03..d07fb27 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -242,6 +242,7 @@ struct mmc_host {
>  #define MMC_CAP2_CACHE_CTRL	(1 << 1)	/* Allow cache control */
>  #define MMC_CAP2_POWEROFF_NOTIFY (1 << 2)	/* Notify poweroff
> supported */
>  #define MMC_CAP2_NO_MULTI_READ	(1 << 3)	/* Multiblock reads
> don't work */
> +#define MMC_CAP2_NOSLEEP	(1 << 4)	/* Don't allow sleep command

Can we rename this CAP to something like "MMC_CAP2_NO_MMC_SLEEP_CMD" to make
it more specific?

> */
> 
>  	mmc_pm_flag_t		pm_caps;	/* supported pm features */
>  	unsigned int        power_notify_type;
> --
> 1.7.5.4
> 
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