On Tue, 19 May 2020 at 13:33, Yoshihiro Shimoda
<yoshihiro.shimoda.uh@xxxxxxxxxxx> wrote:
>
> The commit 432356793415 ("mmc: core: Enable power_off_notify for
> eMMC shutdown sequence") enabled the power off notification
> even if MMC_CAP2_POWEROFF_NOTIFY (MMC_CAP2_FULL_PWR_CYCLE now) is
> not set. However, the mmc core lacks to issue the power off
> notificaiton when Suspend-to-{RAM,Disk} happens on the system.
This isn't an entirely correct description, I think.
If the host supports MMC_CAP2_FULL_PWR_CYCLE (both vmmc and vqmmc can
be powered on/off), we use power-off-notification during system
suspend, in case the eMMC card also supports it. Otherwise we send the
sleep command.
This behaviour was decided on purpose and it's mainly because without
MMC_CAP2_FULL_PWR_CYCLE, we assume that vqmmc remains always-on. In
this case, it simply seemed better to use the sleep command, rather
than the power-off-notification, as we aren't really going to do a
full power off anyway.
Kind regards
Uffe
>
> So, add Suspend-to-RAM support at first because this is easy to
> check by using pm_suspend_target_state condition on _mmc_suspend().
>
> Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
> ---
> drivers/mmc/core/mmc.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 4203303..4a23f83 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -11,6 +11,7 @@
> #include <linux/of.h>
> #include <linux/slab.h>
> #include <linux/stat.h>
> +#include <linux/suspend.h>
> #include <linux/pm_runtime.h>
>
> #include <linux/mmc/host.h>
> @@ -2027,6 +2028,12 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
> int err = 0;
> unsigned int notify_type = is_suspend ? EXT_CSD_POWER_OFF_SHORT :
> EXT_CSD_POWER_OFF_LONG;
> + bool s2ram = false;
> +
> +#ifdef CONFIG_PM_SLEEP
> + if (pm_suspend_target_state == PM_SUSPEND_MEM)
> + s2ram = true;
> +#endif
>
> mmc_claim_host(host);
>
> @@ -2038,7 +2045,7 @@ static int _mmc_suspend(struct mmc_host *host, bool is_suspend)
> goto out;
>
> if (mmc_can_poweroff_notify(host->card) &&
> - ((host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) || !is_suspend))
> + ((host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) || !is_suspend || s2ram))
> err = mmc_poweroff_notify(host->card, notify_type);
> else if (mmc_can_sleep(host->card))
> err = mmc_sleep(host);
> --
> 2.7.4
>
