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: Monday, December 19, 2011 5:28 PM
> To: Subhash Jadavani
> Cc: linux-mmc@vger.kernel.org; 'Chris Ball'; Per FORLIN; Johan RUDHOLM;
> 'Lee Jones'
> Subject: Re: [PATCH V2] mmc: core: Add option to prevent eMMC sleep
> command
> 
> Subhash Jadavani wrote:
> >   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.
> 
> OK, fixed in v3 patch. May I add your Ack as well?
Yes, sure.

Regards,
Subhash

> 
> Br
> Ulf Hansson
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