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

[Subhash Jadavani <subhashj@codeaurora.org>]

  On 12/19/2011 4:42 PM, Ulf Hansson wrote:
> 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?
Yes, it sounds good.

Regards,
Subhash
>
>>> */
>>>
>>>      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
>
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