Re: [PATCH v5] mmc: support BKOPS feature for eMMC

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On Thu, Jan 5, 2012 at 6:25 AM, Jaehoon Chung <jh80.chung@xxxxxxxxxxx> wrote:
>
> Enable eMMC background operations (BKOPS) feature.
>
> If URGENT_BKOPS is set after a response, note that BKOPS
> are required. After all I/O requests are finished, run
> BKOPS if required. Should read/write operations be requested
> during BKOPS, first issue HPI to interrupt the ongoing BKOPS
> and then service the request.
>
> If you want to enable this feature, set MMC_CAP2_BKOPS.
>
> Future considerations
>  * Check BKOPS_LEVEL=1 and start BKOPS in a preventive manner.
>  * Interrupt ongoing BKOPS before powering off the card.
>  * How get BKOPS_STATUS value.(periodically send ext_csd command?)
>
> Signed-off-by: Jaehoon Chung <jh80.chung@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> ---
> Changelog V5:
>        - Rebase based on the latest mmc-next.
>        - modify codes based-on Chris's comment
> Changelog V4:
>        - Add mmc_read_bkops_status
>        - When URGENT_BKOPS(level2-3), didn't use HPI command.
>        - In mmc_switch(), use R1B/R1 according to level.
> Changelog V3:
>        - move the bkops setting's location in mmc_blk_issue_rw_rq
>        - modify condition checking
>        - bkops_en is assigned ext_csd[EXT_CSD_BKOPS_EN] instead of "1"
>        - remove the unused code
>        - change pr_debug instead of pr_warn in mmc_send_hpi_cmd
>        - Add the Future consideration suggested by Per
> Changelog V2:
>        - Use EXCEPTION_STATUS instead of URGENT_BKOPS
>        - Add function to check Exception_status(for eMMC4.5)
>
>  drivers/mmc/card/block.c   |   11 +++++
>  drivers/mmc/card/queue.c   |    3 +
>  drivers/mmc/core/core.c    |  105 ++++++++++++++++++++++++++++++++++++++++++++
>  drivers/mmc/core/mmc.c     |    8 +++
>  drivers/mmc/core/mmc_ops.c |   12 +++++-
>  include/linux/mmc/card.h   |   13 +++++
>  include/linux/mmc/core.h   |    4 ++
>  include/linux/mmc/host.h   |    1 +
>  include/linux/mmc/mmc.h    |   19 ++++++++
>  9 files changed, 175 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/mmc/card/block.c b/drivers/mmc/card/block.c
> index 0cad48a..5e3c580 100644
> --- a/drivers/mmc/card/block.c
> +++ b/drivers/mmc/card/block.c
> @@ -1273,6 +1273,17 @@ static int mmc_blk_issue_rw_rq(struct mmc_queue *mq, struct request *rqc)
>                type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
>                mmc_queue_bounce_post(mq_rq);
>
> +               /*
> +                * Check BKOPS urgency from each R1 response
> +                */
> +               if (mmc_card_mmc(card) &&
> +                       (brq->cmd.flags == MMC_RSP_R1B ||
> +                        brq->cmd.flags == MMC_RSP_R1) &&

I tested this patch on my setup and this condition never hit, as other
flags are also set in cmd.flags
It should have been
(brq->cmd.flags & MMC_RSP_R1B ||
 brq->cmd.flags & MMC_RSP_R1)


> +                       (brq->cmd.resp[0] & R1_EXCEPTION_EVENT)) {
> +                       if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS))

This causes a crash on my test setup. The next req is already given to
the controller (see the mmc_start_req call a few lines above) and a
parallel request to read BKOPS_STATUS is interfering with it. This
won't work with any host controller driver which implements async_req
functions.

But there is no need to read BKOPS_STATUS at this stage anyway. By
checking R1_EXCEPTION_EVENT and the BKOPS bit inside the response, the
need to do BKOPS can be determined (as only a urgen_bkops state would
trigger a R1_EXCEPTION_EVENT in the first place)

> +                               mmc_card_set_need_bkops(card);
> +               }
> +
>                switch (status) {
>                case MMC_BLK_SUCCESS:
>                case MMC_BLK_PARTIAL:
> diff --git a/drivers/mmc/card/queue.c b/drivers/mmc/card/queue.c
> index 2517547..fd11a31 100644
> --- a/drivers/mmc/card/queue.c
> +++ b/drivers/mmc/card/queue.c
> @@ -66,6 +66,8 @@ static int mmc_queue_thread(void *d)
>                spin_unlock_irq(q->queue_lock);
>
>                if (req || mq->mqrq_prev->req) {
> +                       if (mmc_card_doing_bkops(mq->card))
> +                               mmc_interrupt_bkops(mq->card);
>                        set_current_state(TASK_RUNNING);
>                        mq->issue_fn(mq, req);
>                } else {
> @@ -73,6 +75,7 @@ static int mmc_queue_thread(void *d)
>                                set_current_state(TASK_RUNNING);
>                                break;
>                        }
> +                       mmc_start_bkops(mq->card);
>                        up(&mq->thread_sem);
>                        schedule();
>                        down(&mq->thread_sem);
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 4770807..4579b24 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -238,6 +238,50 @@ mmc_start_request(struct mmc_host *host, struct mmc_request *mrq)
>        host->ops->request(host, mrq);
>  }
>
> +/**
> + *     mmc_start_bkops - start BKOPS for supported cards
> + *     @card: MMC card to start BKOPS
> + *
> + *     Start background operations whenever requested.
> + *     when the urgent BKOPS bit is set in a R1 command response
> + *     then background operations should be started immediately.
> +*/
> +void mmc_start_bkops(struct mmc_card *card)
> +{
> +       int err;
> +       unsigned long flags;
> +
> +       BUG_ON(!card);
> +       if (!card->ext_csd.bkops_en || !(card->host->caps2 & MMC_CAP2_BKOPS))
> +               return;
> +
> +       /*
> +        * If card is already doing bkops or need for
> +        * bkops flag is not set, then do nothing just
> +        * return
> +        */
> +       if (mmc_card_doing_bkops(card) || !mmc_card_need_bkops(card))
> +               return;
> +
> +       mmc_claim_host(card->host);
> +       err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> +                       EXT_CSD_BKOPS_START, 1, 0);
> +       if (err) {
> +               pr_warning("%s: error %d starting bkops\n",
> +                          mmc_hostname(card->host), err);
> +               mmc_card_clr_need_bkops(card);
> +               goto out;
> +       }
> +       spin_lock_irqsave(&card->host->lock, flags);
> +       mmc_card_clr_need_bkops(card);
> +       if (card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2)
> +               mmc_card_set_doing_bkops(card);
> +       spin_unlock_irqrestore(&card->host->lock, flags);
> +out:
> +       mmc_release_host(card->host);
> +}
> +EXPORT_SYMBOL(mmc_start_bkops);
> +
>  static void mmc_wait_done(struct mmc_request *mrq)
>  {
>        complete(&mrq->completion);
> @@ -472,6 +516,67 @@ int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd, int retries
>  EXPORT_SYMBOL(mmc_wait_for_cmd);
>
>  /**
> + *     mmc_interrupt_bkops - interrupt ongoing BKOPS
> + *     @card: MMC card to check BKOPS
> + *
> + *     Send HPI command to interrupt ongoing background operations,
> + *     to allow rapid servicing of foreground operations,e.g. read/
> + *     writes. Wait until the card comes out of the programming state
> + *     to avoid errors in servicing read/write requests.
> + */
> +int mmc_interrupt_bkops(struct mmc_card *card)
> +{
> +       int err = 0;
> +       unsigned long flags;
> +
> +       BUG_ON(!card);
> +
> +       err = mmc_interrupt_hpi(card);
> +
> +       spin_lock_irqsave(&card->host->lock, flags);
> +       mmc_card_clr_doing_bkops(card);
> +       spin_unlock_irqrestore(&card->host->lock, flags);
> +
> +       return err;
> +}
> +EXPORT_SYMBOL(mmc_interrupt_bkops);
> +
> +int mmc_read_bkops_status(struct mmc_card *card)
> +{
> +       int err;
> +       u8 ext_csd[512];
> +
> +       err = mmc_send_ext_csd(card, ext_csd);
> +       if (err)
> +               return err;
> +
> +       card->ext_csd.raw_bkops_status = ext_csd[EXT_CSD_BKOPS_STATUS];
> +       card->ext_csd.raw_exception_status = ext_csd[EXT_CSD_EXCEPTION_STATUS];
> +
> +       return 0;
> +}
> +EXPORT_SYMBOL(mmc_read_bkops_status);
> +
> +int mmc_is_exception_event(struct mmc_card *card, unsigned int value)
> +{
> +       int err;
> +
> +       err = mmc_read_bkops_status(card);
> +       if (err) {
> +               pr_err("%s: Didn't read bkops status : %d\n",
> +                      mmc_hostname(card->host), err);
> +               return 0;
> +       }
> +
> +       /* In eMMC 4.41, R1_EXCEPTION_EVENT is URGENT_BKOPS */
> +       if (card->ext_csd.rev == 5)
> +               return 1;
> +
> +       return (card->ext_csd.raw_exception_status & value) ? 1 : 0;
> +}
> +EXPORT_SYMBOL(mmc_is_exception_event);
> +
> +/**
>  *     mmc_set_data_timeout - set the timeout for a data command
>  *     @data: data phase for command
>  *     @card: the MMC card associated with the data transfer
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 4af69d0..e132fa8 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -459,6 +459,14 @@ static int mmc_read_ext_csd(struct mmc_card *card, u8 *ext_csd)
>        }
>
>        if (card->ext_csd.rev >= 5) {
> +               /* check whether the eMMC card support BKOPS */
> +               if (ext_csd[EXT_CSD_BKOPS_SUPPORT] & 0x1) {
> +                       card->ext_csd.bkops = 1;
> +                       card->ext_csd.bkops_en = ext_csd[EXT_CSD_BKOPS_EN];
> +                       card->ext_csd.raw_bkops_status =
> +                               ext_csd[EXT_CSD_BKOPS_STATUS];
> +               }
> +
>                /* check whether the eMMC card supports HPI */
>                if (ext_csd[EXT_CSD_HPI_FEATURES] & 0x1) {
>                        card->ext_csd.hpi = 1;
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 4d41fa9..ee3bdb9 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -392,13 +392,23 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
>                  (index << 16) |
>                  (value << 8) |
>                  set;
> -       cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
> +       cmd.flags = MMC_CMD_AC;
> +       if (index == EXT_CSD_BKOPS_START &&
> +           card->ext_csd.raw_bkops_status < EXT_CSD_BKOPS_LEVEL_2)
> +               cmd.flags |= MMC_RSP_SPI_R1 | MMC_RSP_R1;
> +       else
> +               cmd.flags |= MMC_RSP_SPI_R1B | MMC_RSP_R1B;
> +
>        cmd.cmd_timeout_ms = timeout_ms;
>
>        err = mmc_wait_for_cmd(card->host, &cmd, MMC_CMD_RETRIES);
>        if (err)
>                return err;
>
> +       /* No need to check card status in case of BKOPS switch*/
> +       if (index == EXT_CSD_BKOPS_START)
> +               return 0;
> +
>        /* Must check status to be sure of no errors */
>        do {
>                err = mmc_send_status(card, &status);
> diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
> index 9478a6b..5c7b025 100644
> --- a/include/linux/mmc/card.h
> +++ b/include/linux/mmc/card.h
> @@ -70,9 +70,12 @@ struct mmc_ext_csd {
>        unsigned int            cache_size;             /* Units: KB */
>        bool                    hpi_en;                 /* HPI enablebit */
>        bool                    hpi;                    /* HPI support bit */
> +       bool                    bkops;          /* background support bit */
> +       bool                    bkops_en;       /* background enable bit */
>        unsigned int            hpi_cmd;                /* cmd used as HPI */
>        unsigned int            boot_ro_lock;           /* ro lock support */
>        bool                    boot_ro_lockable;
> +       u8                      raw_exception_status;   /* 53 */
>        u8                      raw_partition_support;  /* 160 */
>        u8                      raw_erased_mem_count;   /* 181 */
>        u8                      raw_ext_csd_structure;  /* 194 */
> @@ -86,6 +89,7 @@ struct mmc_ext_csd {
>        u8                      raw_sec_erase_mult;     /* 230 */
>        u8                      raw_sec_feature_support;/* 231 */
>        u8                      raw_trim_mult;          /* 232 */
> +       u8                      raw_bkops_status;       /* 246 */
>        u8                      raw_sectors[4];         /* 212 - 4 bytes */
>
>        unsigned int            feature_support;
> @@ -216,6 +220,8 @@ struct mmc_card {
>  #define MMC_STATE_ULTRAHIGHSPEED (1<<5)                /* card is in ultra high speed mode */
>  #define MMC_CARD_SDXC          (1<<6)          /* card is SDXC */
>  #define MMC_CARD_REMOVED       (1<<7)          /* card has been removed */
> +#define MMC_STATE_NEED_BKOPS   (1<<8)          /* card need to do BKOPS */
> +#define MMC_STATE_DOING_BKOPS  (1<<9)          /* card is doing BKOPS */
>        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 */
> @@ -380,6 +386,8 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
>  #define mmc_sd_card_uhs(c)     ((c)->state & MMC_STATE_ULTRAHIGHSPEED)
>  #define mmc_card_ext_capacity(c) ((c)->state & MMC_CARD_SDXC)
>  #define mmc_card_removed(c)    ((c) && ((c)->state & MMC_CARD_REMOVED))
> +#define mmc_card_need_bkops(c) ((c)->state & MMC_STATE_NEED_BKOPS)
> +#define mmc_card_doing_bkops(c)        ((c)->state & MMC_STATE_DOING_BKOPS)
>
>  #define mmc_card_set_present(c)        ((c)->state |= MMC_STATE_PRESENT)
>  #define mmc_card_set_readonly(c) ((c)->state |= MMC_STATE_READONLY)
> @@ -390,6 +398,11 @@ static inline void __maybe_unused remove_quirk(struct mmc_card *card, int data)
>  #define mmc_sd_card_set_uhs(c) ((c)->state |= MMC_STATE_ULTRAHIGHSPEED)
>  #define mmc_card_set_ext_capacity(c) ((c)->state |= MMC_CARD_SDXC)
>  #define mmc_card_set_removed(c) ((c)->state |= MMC_CARD_REMOVED)
> +#define mmc_card_set_need_bkops(c)     ((c)->state |= MMC_STATE_NEED_BKOPS)
> +#define mmc_card_set_doing_bkops(c)    ((c)->state |= MMC_STATE_DOING_BKOPS)
> +
> +#define mmc_card_clr_need_bkops(c)     ((c)->state &= ~MMC_STATE_NEED_BKOPS)
> +#define mmc_card_clr_doing_bkops(c)    ((c)->state &= ~MMC_STATE_DOING_BKOPS)
>
>  /*
>  * Quirk add/remove for MMC products.
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index 87a976c..45357c7 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -134,6 +134,9 @@ struct mmc_host;
>  struct mmc_card;
>  struct mmc_async_req;
>
> +extern int mmc_interrupt_bkops(struct mmc_card *);
> +extern int mmc_read_bkops_status(struct mmc_card *);
> +extern int mmc_is_exception_event(struct mmc_card *, unsigned int);
>  extern struct mmc_async_req *mmc_start_req(struct mmc_host *,
>                                           struct mmc_async_req *, int *);
>  extern int mmc_interrupt_hpi(struct mmc_card *);
> @@ -163,6 +166,7 @@ extern int mmc_can_sanitize(struct mmc_card *card);
>  extern int mmc_can_secure_erase_trim(struct mmc_card *card);
>  extern int mmc_erase_group_aligned(struct mmc_card *card, unsigned int from,
>                                   unsigned int nr);
> +extern void mmc_start_bkops(struct mmc_card *card);
>  extern unsigned int mmc_calc_max_discard(struct mmc_card *card);
>
>  extern int mmc_set_blocklen(struct mmc_card *card, unsigned int blocklen);
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 031d865..b8cb140 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -248,6 +248,7 @@ struct mmc_host {
>  #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_NO_SLEEP_CMD  (1 << 4)        /* Don't allow sleep command */
> +#define MMC_CAP2_BKOPS         (1 << 5)        /* BKOPS supported */
>
>        mmc_pm_flag_t           pm_caps;        /* supported pm features */
>        unsigned int        power_notify_type;
> diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
> index 665548e..8cc1a03 100644
> --- a/include/linux/mmc/mmc.h
> +++ b/include/linux/mmc/mmc.h
> @@ -138,6 +138,7 @@ static inline bool mmc_op_multi(u32 opcode)
>  #define R1_CURRENT_STATE(x)    ((x & 0x00001E00) >> 9) /* sx, b (4 bits) */
>  #define R1_READY_FOR_DATA      (1 << 8)        /* sx, a */
>  #define R1_SWITCH_ERROR                (1 << 7)        /* sx, c */
> +#define R1_EXCEPTION_EVENT     (1 << 6)        /* sx, a */
>  #define R1_APP_CMD             (1 << 5)        /* sr, c */
>
>  #define R1_STATE_IDLE  0
> @@ -273,11 +274,14 @@ struct _mmc_csd {
>  #define EXT_CSD_FLUSH_CACHE            32      /* W */
>  #define EXT_CSD_CACHE_CTRL             33      /* R/W */
>  #define EXT_CSD_POWER_OFF_NOTIFICATION 34      /* R/W */
> +#define EXT_CSD_EXCEPTION_STATUS       54      /* RO */
>  #define EXT_CSD_GP_SIZE_MULT           143     /* R/W */
>  #define EXT_CSD_PARTITION_ATTRIBUTE    156     /* R/W */
>  #define EXT_CSD_PARTITION_SUPPORT      160     /* RO */
>  #define EXT_CSD_HPI_MGMT               161     /* R/W */
>  #define EXT_CSD_RST_N_FUNCTION         162     /* R/W */
> +#define EXT_CSD_BKOPS_EN               163     /* R/W */
> +#define EXT_CSD_BKOPS_START            164     /* W */
>  #define EXT_CSD_SANITIZE_START         165     /* W */
>  #define EXT_CSD_WR_REL_PARAM           166     /* RO */
>  #define EXT_CSD_BOOT_WP                        173     /* R/W */
> @@ -311,9 +315,11 @@ struct _mmc_csd {
>  #define EXT_CSD_PWR_CL_200_360         237     /* RO */
>  #define EXT_CSD_PWR_CL_DDR_52_195      238     /* RO */
>  #define EXT_CSD_PWR_CL_DDR_52_360      239     /* RO */
> +#define EXT_CSD_BKOPS_STATUS           246     /* RO */
>  #define EXT_CSD_POWER_OFF_LONG_TIME    247     /* RO */
>  #define EXT_CSD_GENERIC_CMD6_TIME      248     /* RO */
>  #define EXT_CSD_CACHE_SIZE             249     /* RO, 4 bytes */
> +#define EXT_CSD_BKOPS_SUPPORT          502     /* RO */
>  #define EXT_CSD_HPI_FEATURES           503     /* RO */
>
>  /*
> @@ -379,4 +385,17 @@ struct _mmc_csd {
>  #define MMC_SWITCH_MODE_CLEAR_BITS     0x02    /* Clear bits which are 1 in value */
>  #define MMC_SWITCH_MODE_WRITE_BYTE     0x03    /* Set target to value */
>
> +/*
> + * BKOPS status level
> + */
> +#define EXT_CSD_BKOPS_LEVEL_2          0x2
> +
> +/*
> + * EXCEPTION_EVENT_STATUS field (eMMC4.5)
> + */
> +#define EXT_CSD_URGENT_BKOPS           BIT(0)
> +#define EXT_CSD_DYNCAP_NEEDED          BIT(1)
> +#define EXT_CSD_SYSPOOL_EXHAUSTED      BIT(2)
> +#define EXT_CSD_PACKED_FAILURE         BIT(3)
> +
>  #endif /* LINUX_MMC_MMC_H */
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