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

[Ulf Hansson <ulf.hansson@stericsson.com>]

Subhash Jadavani wrote:
> 
>> -----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?
> 

The "cap" actually disables the execution of the mmc_card_awake|sleep 
functions which is not (e)MMC specific functions.

I could change to someting like with *SLEEP_CMD but without *MMC* if 
that sounds better?

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

Br
Ulf Hansson