Re: [PATCH] mmc: sleep notification

Ulf Hansson
2015-03-10T12:07:45Z

On 10 March 2015 at 10:36, Avi Shchislowski
<avi.shchislowski@sandisk.com> 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.

Oh, just great! JEDEC has invented yet another way of how to send a
device to sleep state. I wonder what was wrong with the CMD5 option.

Anyway, thanks for looking into this.

>
> Signed-off-by: Alex Lemberg <alex.lemberg@sandisk.com>
> Signed-off-by: Avi Shchislowski <avi.shchislowski@sandisk.com>
> ---
> drivers/mmc/card/block.c | 19 +++++-
> drivers/mmc/core/core.c | 16 +++++-
> drivers/mmc/core/core.h | 2 +
> drivers/mmc/core/mmc.c | 143 +++++++++++++++++++++++++++++++++++++++++++---
> include/linux/mmc/card.h | 6 ++
> include/linux/mmc/host.h | 1 +
> include/linux/mmc/mmc.h | 2 +
> 7 files changed, 180 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 4409d79..f511ecc3 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -2010,9 +2010,26 @@ static int mmc_blk_issue_rq(struct mmc_queue *mq, struct request *req)
> unsigned long flags;
> unsigned int cmd_flags = req ? req->cmd_flags : 0;
>
> - if (req && !mq->mqrq_prev->req)
> + if (unlikely(req && mmc_card_mmc(card) &&
> + (card->ext_csd.power_off_notification ==
> + EXT_CSD_SLEEP_NOTIFICATION))) {
> + /* restoring the power_off_notification
> + * field's state to as it was before so
> + * that the sleep notification will be
> + * able to resume later
> + */
> + card->ext_csd.power_off_notification = EXT_CSD_POWER_ON;
> + }
> +
> + if (req && !mq->mqrq_prev->req) {
> /* claim host only for the first request */
> mmc_get_card(card);
> + if (unlikely(req &&
> + mmc_card_doing_sleep_notify(card))) {
> + mmc_interrupt_hpi(card);
> + mmc_card_clr_sleep_notify(card);
> + }
> + }

Both above new added code blocks makes no sense to me. Why does the
mmc block layer need to care about this?

>
> ret = mmc_blk_part_switch(card, md);
> if (ret) {
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 5bda29b..a090593 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -271,7 +271,8 @@ void mmc_start_bkops(struct mmc_card *card, bool from_exception)
>
> BUG_ON(!card);
>
> - if (!card->ext_csd.bkops_en || mmc_card_doing_bkops(card))
> + if (!card->ext_csd.bkops_en || mmc_card_doing_bkops(card) ||
> + mmc_card_doing_sleep_notify(card))

We can't do BKOPS when the card is suspended (which is when the card
may be put in sleep state), so no need to protect for this.

> return;
>
> err = mmc_read_bkops_status(card);
> @@ -2630,6 +2631,19 @@ int mmc_pm_notify(struct notifier_block *notify_block,
> err = host->bus_ops->pre_suspend(host);
> if (!err)
> break;
> + if (host->card && host->bus_ops->suspend) {

Nope, this is the wrong place for this code. You should look into
mmc.c for adding this.

> + err = mmc_sleep_notify(host->card);
> + /* We assume that HPI was sent
> + * in case of -ETIMEDOUT error,
> + * so suspend flow can be continued
> + */
> + if (err && err != -ETIMEDOUT) {
> + pr_err("%s:sleep notify err=%d\n",
> + __func__, err);
> + return -EBUSY;
> + }
> + break;
> + }
>
> /* Calling bus_ops->remove() with a claimed host can deadlock */
> host->bus_ops->remove(host);
> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
> index d76597c..b6b4431 100644
> --- a/drivers/mmc/core/core.h
> +++ b/drivers/mmc/core/core.h
> @@ -14,6 +14,7 @@
> #include <linux/delay.h>
>
> #define MMC_CMD_RETRIES 3
> +#define MMC_SLEEP_NOTIFY_MAX_TIME 0x17
>
> struct mmc_bus_ops {
> void (*remove)(struct mmc_host *);
> @@ -33,6 +34,7 @@ void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
> void mmc_detach_bus(struct mmc_host *host);
>
> void mmc_init_erase(struct mmc_card *card);
> +int mmc_sleep_notify(struct mmc_card *card);

If we need a separate function to deal with this, it should be static
function within mmc.c.

>
> void mmc_set_chip_select(struct mmc_host *host, int mode);
> void mmc_set_clock(struct mmc_host *host, unsigned int hz);
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 02ad792..1d97d24 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -57,6 +57,11 @@ static const unsigned int tacc_mant[] = {
> __res & __mask; \
> })
>
> +#define GET_SLEEP_NOTIFY_TIME(value) \
> + (10 * (1 << (unsigned int)(value)))
> +#define GET_SLEEP_NOTIFY_TIME_MSEC(value) \
> + (DIV_ROUND_UP(GET_SLEEP_NOTIFY_TIME(value), 1000))
> +
> /*
> * Given the decoded CSD structure, decode the raw CID to our CID structure.
> */
> @@ -571,6 +576,8 @@ static int mmc_decode_ext_csd(struct mmc_card *card, u8 *ext_csd)
> card->ext_csd.ffu_capable =
> (ext_csd[EXT_CSD_SUPPORTED_MODE] & 0x1) &&
> !(ext_csd[EXT_CSD_FW_CONFIG] & 0x1);
> + card->ext_csd.sleep_notify_time =
> + ext_csd[EXT_CSD_SLEEP_NOTIFICATION_TIME];
> }
> out:
> return err;
> @@ -1468,6 +1475,15 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr,
> card->ext_csd.hpi_en = 1;
> }
>
> + /* sleep notify enable/disable for eMMC 5.0 and above */
> + if ((card->ext_csd.rev >= 7) && card->ext_csd.hpi_en &&

Why depend on ext_csd.hpi_en?

> + (card->host->caps2 & MMC_CAP2_SLEEP_NOTIFY) &&

Please don't add a new CAP for this. MMC_CAP2_FULL_PWR_CYCLE tells us
if the card can be fully power gated, I think we can use that
instead!?

> + card->ext_csd.sleep_notify_time > 0 &&
> + card->ext_csd.sleep_notify_time <=
> + MMC_SLEEP_NOTIFY_MAX_TIME) {
> + card->can_sleep_notify = 1;

Instead of adding "can_sleep_notify", let's just encapsulate similar
code as above in a helper function which tells us if card supports
"sleep notification".

Compare how mmc_can_sleep() is implemented and used.

> + }
> +
> /*
> * If cache size is higher than 0, this indicates
> * the existence of cache and it can be turned on.
> @@ -1576,6 +1592,33 @@ static int mmc_sleep(struct mmc_host *host)
> return err;
> }
>
> +/*
> + * check if device is in program state (busy)
> + */
> +static bool mmc_device_prg_state(struct mmc_card *card)
> +{
> + int rc;
> + u32 status;
> + bool state;
> +
> + mmc_get_card(card);
> + rc = mmc_send_status(card, &status);
> + if (rc) {
> + pr_err("%s: Get card status fail. rc=%d\n",
> + mmc_hostname(card->host), rc);
> + state = false;
> + goto out;
> + }
> +
> + if (R1_CURRENT_STATE(status) == R1_STATE_PRG)
> + state = true;
> + else
> + state = false;
> +out:
> + mmc_put_card(card);
> + return state;
> +}
> +
> static int mmc_can_poweroff_notify(const struct mmc_card *card)
> {
> return card &&
> @@ -1585,22 +1628,108 @@ static int mmc_can_poweroff_notify(const struct mmc_card *card)
>
> static int mmc_poweroff_notify(struct mmc_card *card, unsigned int notify_type)
> {
> - unsigned int timeout = card->ext_csd.generic_cmd6_time;
> + unsigned int timeout_ms = card->ext_csd.generic_cmd6_time;

What's reason to do a rename in this patch? If you want that as a
clarification of the code, please do that in a separate patch.

> int err;
> + bool use_busy_signal;
>
> /* Use EXT_CSD_POWER_OFF_SHORT as default notification type. */
> if (notify_type == EXT_CSD_POWER_OFF_LONG)
> - timeout = card->ext_csd.power_off_longtime;
> + timeout_ms = card->ext_csd.power_off_longtime;
> + else if (notify_type == EXT_CSD_SLEEP_NOTIFICATION) {
> + /* calculate the maximum timeout for the
> + * switch command when notifying the device
> + * that it is about to move to sleep */
> + timeout_ms = GET_SLEEP_NOTIFY_TIME_MSEC(
> + card->ext_csd.sleep_notify_time);
> + }
>
> + /* do not wait on busy signal in case of
> + * Sleep Notification - to let host get
> + * another requests

At this point, there should be no other request. Or what am I missing?

> + */
> + use_busy_signal = (notify_type == EXT_CSD_SLEEP_NOTIFICATION) ?
> + false : true;
> err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_POWER_OFF_NOTIFICATION,
> - notify_type, timeout, true, false, false);
> - if (err)
> + notify_type, timeout_ms,
> + use_busy_signal, false, false);
> + if (!err) {
> + card->ext_csd.power_off_notification = notify_type;
> + } else {
> pr_err("%s: Power Off Notification timed out, %u\n",
> - mmc_hostname(card->host), timeout);
> + mmc_hostname(card->host), timeout_ms);
> + }
> +
> + return err;
> +}
>
> - /* Disable the power off notification after the switch operation. */
> - card->ext_csd.power_off_notification = EXT_CSD_NO_POWER_NOTIFICATION;

Why remove this?

> +int mmc_sleep_notify(struct mmc_card *card)

I don't understand the need for this function. From what scenarios do
we want to invoke it?

> +{
> + int err = 0;
> + bool is_busy = 0;
> + unsigned long prg_wait = 0;
> +
> + if (!card->can_sleep_notify || !mmc_can_poweroff_notify(card))
> + return 0;
> +
> + if (!mmc_card_doing_sleep_notify(card)) {
> + mmc_get_card(card);
> + mmc_card_set_sleep_notify(card);
> + err = mmc_poweroff_notify(card,
> + EXT_CSD_SLEEP_NOTIFICATION);
> + mmc_put_card(card);
> + if (err) {
> + pr_err("%s: mmc_poweroff_notify failed with %d\n",
> + __func__, err);
> + goto out;
> + }
> +
> + prg_wait = jiffies +
> + msecs_to_jiffies(GET_SLEEP_NOTIFY_TIME_MSEC(
> + card->ext_csd.sleep_notify_time));
> + }
> +
> + /*
> + * Loop will run until:
> + * 1. Device is no more in Busy state
> + * 2. Sleep notification is not interrupted by HPI & IO request
> + */
> + do {
> + /* added some delay to avoid sending card status too often */
> + msleep(20);
> + err = 0;
> + /* Stop polling in case sleep notification was HPIed already */
> + if (!mmc_card_doing_sleep_notify(card)) {
> + is_busy = mmc_device_prg_state(card);
> + if (is_busy)
> + err = -EBUSY;
> + break;
> + }
> + is_busy = mmc_device_prg_state(card);
> + if (is_busy && time_after(jiffies, prg_wait)) {
> + /*
> + * making sure we are still in busy before
> + * sending HPI due to timeout error
> + */
> + is_busy = mmc_device_prg_state(card);
> + if (is_busy) {
> + if (mmc_card_doing_sleep_notify(card)) {
> + card->ext_csd.power_off_notification =
> + EXT_CSD_POWER_ON;
> + mmc_interrupt_hpi(card);
> + }
> + err = -ETIMEDOUT;
> + break;
> + }
> + }
> + } while (is_busy);
> +
> +out:
> + mmc_card_clr_sleep_notify(card);
> + if (err) {
> + pr_err("%s: mmc_poweroff_notify for sleep failed with %d\n",
> + mmc_hostname(card->host), err);
> + }
>
> return err;
> }
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 4d69c00..6998344 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -62,6 +62,7 @@ struct mmc_ext_csd {
> unsigned int sa_timeout; /* Units: 100ns */
> unsigned int generic_cmd6_time; /* Units: 10ms */
> unsigned int power_off_longtime; /* Units: ms */
> + unsigned int sleep_notify_time; /* Units: us */
> u8 power_off_notification; /* state */
> unsigned int hs_max_dtr;
> unsigned int hs200_max_dtr;
> @@ -262,6 +263,7 @@ struct mmc_card {
> #define MMC_CARD_REMOVED (1<<4) /* card has been removed */
> #define MMC_STATE_DOING_BKOPS (1<<5) /* card is doing BKOPS */
> #define MMC_STATE_SUSPENDED (1<<6) /* card is suspended */
> +#define MMC_STATE_SLEEP_NOTIFY (1<<7) /* card in sleep notify */

I think MMC_STATE_SUSPENDED should be enough, we don't need another
one specific for SLEEP_NOTIFY.

> unsigned int quirks; /* card quirks */
> #define MMC_QUIRK_LENIENT_FN0 (1<<0) /* allow SDIO FN0 writes outside of the VS CCCR range */
> #define MMC_QUIRK_BLKSZ_FOR_BYTE_MODE (1<<1) /* use func->cur_blksize */
> @@ -309,6 +311,7 @@ struct mmc_card {
> struct dentry *debugfs_root;
> struct mmc_part part[MMC_NUM_PHY_PARTITION]; /* physical partitions */
> unsigned int nr_parts;
> + u8 can_sleep_notify; /* sleep_notify on/off */

As stated, please remove.

> };
>
> /*
> @@ -427,6 +430,7 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
> #define mmc_card_removed(c) ((c) && ((c)->state & MMC_CARD_REMOVED))
> #define mmc_card_doing_bkops(c) ((c)->state & MMC_STATE_DOING_BKOPS)
> #define mmc_card_suspended(c) ((c)->state & MMC_STATE_SUSPENDED)
> +#define mmc_card_doing_sleep_notify(c) ((c)->state & MMC_STATE_SLEEP_NOTIFY)
>
> #define mmc_card_set_present(c) ((c)->state |= MMC_STATE_PRESENT)
> #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
> @@ -437,6 +441,8 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
> #define mmc_card_clr_doing_bkops(c) ((c)->state &= ~MMC_STATE_DOING_BKOPS)
> #define mmc_card_set_suspended(c) ((c)->state |= MMC_STATE_SUSPENDED)
> #define mmc_card_clr_suspended(c) ((c)->state &= ~MMC_STATE_SUSPENDED)
> +#define mmc_card_set_sleep_notify(c) ((c)->state |= MMC_STATE_SLEEP_NOTIFY)
> +#define mmc_card_clr_sleep_notify(c) ((c)->state &= ~MMC_STATE_SLEEP_NOTIFY)
>
> /*
> * Quirk add/remove for MMC products.
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 9f32270..4c0542a 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -291,6 +291,7 @@ struct mmc_host {
> MMC_CAP2_HS400_1_2V)
> #define MMC_CAP2_HSX00_1_2V (MMC_CAP2_HS200_1_2V_SDR | MMC_CAP2_HS400_1_2V)
> #define MMC_CAP2_SDIO_IRQ_NOTHREAD (1 << 17)
> +#define MMC_CAP2_SLEEP_NOTIFY (1 << 18) /* sleep notify supported */
>
> mmc_pm_flag_t pm_caps; /* supported pm features */
>
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 49ad7a9..69bda9a 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -314,6 +314,7 @@ struct _mmc_csd {
> #define EXT_CSD_PWR_CL_52_360 202 /* RO */
> #define EXT_CSD_PWR_CL_26_360 203 /* RO */
> #define EXT_CSD_SEC_CNT 212 /* RO, 4 bytes */
> +#define EXT_CSD_SLEEP_NOTIFICATION_TIME 216 /* RO */
> #define EXT_CSD_S_A_TIMEOUT 217 /* RO */
> #define EXT_CSD_REL_WR_SEC_C 222 /* RO */
> #define EXT_CSD_HC_WP_GRP_SIZE 221 /* RO */
> @@ -408,6 +409,7 @@ struct _mmc_csd {
> #define EXT_CSD_POWER_ON 1
> #define EXT_CSD_POWER_OFF_SHORT 2
> #define EXT_CSD_POWER_OFF_LONG 3
> +#define EXT_CSD_SLEEP_NOTIFICATION 4
>
> #define EXT_CSD_PWR_CL_8BIT_MASK 0xF0 /* 8 bit PWR CLS */
> #define EXT_CSD_PWR_CL_4BIT_MASK 0x0F /* 8 bit PWR CLS */
> --
> 1.7.9.5
>

Kind regards
Uffe