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.ch...@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
---
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) &&
+                       (brq->cmd.resp[0] & R1_EXCEPTION_EVENT)) {
+                       if (mmc_is_exception_event(card, EXT_CSD_URGENT_BKOPS))
+                               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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