RE: [PATCH] mmc: sleep notification

Alex Lemberg
2015-03-10T16:46:26Z

Hi Adrian,

> -----Original Message-----
> From: Adrian Hunter [mailto:adrian.hunter@intel.com]
> Sent: Tuesday, March 10, 2015 6:36 AM
> To: Avi Shchislowski; ulf.hansson@linaro.org
> Cc: linux-mmc@vger.kernel.org; chris@printf.net; Alex Lemberg
> Subject: Re: [PATCH] mmc: sleep notification
>
> On 10/03/15 11:36, Avi Shchislowski wrote:
> > This patch is implements the new additional state of
> > Power_Off_Notification - SLEEP_NOTIFICATION.
> > Until now, the implementation of Power_Off_Notification supported only
> > three modes - POWERED_ON (0x01), POWER_OFF_SHORT (0x02) and
> > POWER_OFF_LONG (0x03).
> >
> > As part of eMMC5.0 before moving to Sleep state hosts may set the
> > POWER_OFF_NOTIFICATION byte to SLEEP_NOTIFICATION (0x04).
> > After setting SLEEP_NOTIFICATION, host should wait for the busy line
> > to be de-asserted.
> > The max timeout allowed for busy line de-assertion defined in
> > SLEEP_NOTIFICATION_TIME byte in EXT_CSD [216].
> > HPI may interrupt the SLEEP_NOTIFICATION operation.
> > In that case POWER_OFF_NOTIFICATION byte will restore to POWERED_ON.
>
> Is it so that the point of SLEEP_NOTIFICATION is to notify that VCC will be
> powered off after the device is put to sleep by CMD5?

>From the spec:

the host should issue a power off notification (POWER_OFF_LONG, POWER_OFF_SHORT )
if it intends to turn off both VCC and VCCQ power supplies or it may use
to a power off notification (SLEEP_NOTIFICATION ) if it intends to turn-off VCC
after moving the device to Sleep state.

>
> At the moment, the card does not get put to sleep if there is support for power-
> off-notification?

Driver will send Sleep only if PON is not supported...

Thanks,
Alex