There are only a few things the recovery needs to do. Primarily, it just
needs to:
        Determine the number of bytes transferred
        Get the card back to transfer state
        Determine whether to retry

There are also a couple of additional features:
        Reset the card before the last retry
        Read one sector at a time

The legacy code spent much effort analyzing command errors, but commands
fail fast, so it is simpler just to give all command errors the same number
of retries.

Signed-off-by: Adrian Hunter <adrian.hun...@intel.com>
---
 drivers/mmc/core/block.c | 289 +++++++++++++++++++++++++----------------------
 1 file changed, 153 insertions(+), 136 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index ac976c84571f..af445e405488 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1549,9 +1549,11 @@ static void mmc_blk_eval_resp_error(struct 
mmc_blk_request *brq)
        }
 }
 
-static enum mmc_blk_status __mmc_blk_err_check(struct mmc_card *card,
-                                              struct mmc_queue_req *mq_mrq)
+static enum mmc_blk_status mmc_blk_err_check(struct mmc_card *card,
+                                            struct mmc_async_req *areq)
 {
+       struct mmc_queue_req *mq_mrq = container_of(areq, struct mmc_queue_req,
+                                                   areq);
        struct mmc_blk_request *brq = &mq_mrq->brq;
        struct request *req = mmc_queue_req_to_req(mq_mrq);
        int need_retune = card->host->need_retune;
@@ -1656,15 +1658,6 @@ static enum mmc_blk_status __mmc_blk_err_check(struct 
mmc_card *card,
        return MMC_BLK_SUCCESS;
 }
 
-static enum mmc_blk_status mmc_blk_err_check(struct mmc_card *card,
-                                            struct mmc_async_req *areq)
-{
-       struct mmc_queue_req *mq_mrq = container_of(areq, struct mmc_queue_req,
-                                                   areq);
-
-       return __mmc_blk_err_check(card, mq_mrq);
-}
-
 static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
                              int disable_multi, bool *do_rel_wr_p,
                              bool *do_data_tag_p)
@@ -1990,6 +1983,7 @@ static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
 }
 
 #define MMC_MAX_RETRIES                5
+#define MMC_DATA_RETRIES       2
 #define MMC_NO_RETRIES         (MMC_MAX_RETRIES + 1)
 
 /* Single sector read during recovery */
@@ -2022,6 +2016,85 @@ static void mmc_blk_ss_read(struct mmc_queue *mq, struct 
request *req)
        mqrq->retries = MMC_NO_RETRIES;
 }
 
+static inline bool mmc_blk_oor_valid(struct mmc_blk_request *brq)
+{
+       return !!brq->mrq.sbc;
+}
+
+static inline u32 mmc_blk_stop_err_bits(struct mmc_blk_request *brq)
+{
+       return mmc_blk_oor_valid(brq) ? CMD_ERRORS : CMD_ERRORS_EXCL_OOR;
+}
+
+/*
+ * Check for errors the host controller driver might not have seen such as
+ * response mode errors or invalid card state.
+ */
+static bool mmc_blk_status_error(struct request *req, u32 status)
+{
+       struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+       struct mmc_blk_request *brq = &mqrq->brq;
+       struct mmc_queue *mq = req->q->queuedata;
+       u32 stop_err_bits;
+
+       if (mmc_host_is_spi(mq->card->host))
+               return 0;
+
+       stop_err_bits = mmc_blk_stop_err_bits(brq);
+
+       return brq->cmd.resp[0]  & CMD_ERRORS    ||
+              brq->stop.resp[0] & stop_err_bits ||
+              status            & stop_err_bits ||
+              (rq_data_dir(req) == WRITE && !mmc_blk_in_tran_state(status));
+}
+
+static inline bool mmc_blk_cmd_started(struct mmc_blk_request *brq)
+{
+       return !brq->sbc.error && !brq->cmd.error &&
+              !(brq->cmd.resp[0] & CMD_ERRORS);
+}
+
+static int mmc_blk_send_stop(struct mmc_card *card)
+{
+       struct mmc_command cmd = {
+               .opcode = MMC_STOP_TRANSMISSION,
+               .flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC,
+       };
+
+       return mmc_wait_for_cmd(card->host, &cmd, 5);
+}
+
+static int mmc_blk_fix_state(struct mmc_card *card, struct request *req)
+{
+       int err;
+
+       mmc_retune_hold_now(card->host);
+
+       mmc_blk_send_stop(card);
+
+       err = card_busy_detect(card, false, req, NULL);
+
+       mmc_retune_release(card->host);
+
+       return err;
+}
+
+/*
+ * Requests are completed by mmc_blk_mq_complete_rq() which sets simple
+ * policy:
+ * 1. A request that has transferred at least some data is considered
+ * successful and will be requeued if there is remaining data to
+ * transfer.
+ * 2. Otherwise the number of retries is incremented and the request
+ * will be requeued if there are remaining retries.
+ * 3. Otherwise the request will be errored out.
+ * That means mmc_blk_mq_complete_rq() is controlled by bytes_xfered and
+ * mqrq->retries. So there are only 4 possible actions here:
+ *     1. do not accept the bytes_xfered value i.e. set it to zero
+ *     2. change mqrq->retries to determine the number of retries
+ *     3. try to reset the card
+ *     4. read one sector at a time
+ */
 static void mmc_blk_mq_rw_recovery(struct mmc_queue *mq, struct request *req)
 {
        int type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
@@ -2029,131 +2102,85 @@ static void mmc_blk_mq_rw_recovery(struct mmc_queue 
*mq, struct request *req)
        struct mmc_blk_request *brq = &mqrq->brq;
        struct mmc_blk_data *md = mq->blkdata;
        struct mmc_card *card = mq->card;
-       static enum mmc_blk_status status;
-
-       brq->retune_retry_done = mqrq->retries;
+       u32 status;
+       u32 blocks;
+       int err;
 
-       status = __mmc_blk_err_check(card, mqrq);
+       /*
+        * Some errors the host driver might not have seen. Set the number of
+        * bytes transferred to zero in that case.
+        */
+       err = __mmc_send_status(card, &status, 0);
+       if (err || mmc_blk_status_error(req, status))
+               brq->data.bytes_xfered = 0;
 
        mmc_retune_release(card->host);
 
        /*
-        * Requests are completed by mmc_blk_mq_complete_rq() which sets simple
-        * policy:
-        * 1. A request that has transferred at least some data is considered
-        * successful and will be requeued if there is remaining data to
-        * transfer.
-        * 2. Otherwise the number of retries is incremented and the request
-        * will be requeued if there are remaining retries.
-        * 3. Otherwise the request will be errored out.
-        * That means mmc_blk_mq_complete_rq() is controlled by bytes_xfered and
-        * mqrq->retries. So there are only 4 possible actions here:
-        *      1. do not accept the bytes_xfered value i.e. set it to zero
-        *      2. change mqrq->retries to determine the number of retries
-        *      3. try to reset the card
-        *      4. read one sector at a time
+        * Try again to get the status. This also provides an opportunity for
+        * re-tuning.
         */
-       switch (status) {
-       case MMC_BLK_SUCCESS:
-       case MMC_BLK_PARTIAL:
-               /* Reset success, and accept bytes_xfered */
-               mmc_blk_reset_success(md, type);
-               break;
-       case MMC_BLK_CMD_ERR:
-               /*
-                * For SD cards, get bytes written, but do not accept
-                * bytes_xfered if that fails. For MMC cards accept
-                * bytes_xfered. Then try to reset. If reset fails then
-                * error out the remaining request, otherwise retry
-                * once (N.B mmc_blk_reset() will not succeed twice in a
-                * row).
-                */
-               if (mmc_card_sd(card)) {
-                       u32 blocks;
-                       int err;
+       if (err)
+               err = __mmc_send_status(card, &status, 0);
 
-                       err = mmc_sd_num_wr_blocks(card, &blocks);
-                       if (err)
-                               brq->data.bytes_xfered = 0;
-                       else
-                               brq->data.bytes_xfered = blocks << 9;
-               }
-               if (mmc_blk_reset(md, card->host, type))
-                       mqrq->retries = MMC_NO_RETRIES;
-               else
-                       mqrq->retries = MMC_MAX_RETRIES - 1;
-               break;
-       case MMC_BLK_RETRY:
-               /*
-                * Do not accept bytes_xfered, but retry up to 5 times,
-                * otherwise same as abort.
-                */
-               brq->data.bytes_xfered = 0;
-               if (mqrq->retries < MMC_MAX_RETRIES)
-                       break;
-               /* Fall through */
-       case MMC_BLK_ABORT:
-               /*
-                * Do not accept bytes_xfered, but try to reset. If
-                * reset succeeds, try once more, otherwise error out
-                * the request.
-                */
-               brq->data.bytes_xfered = 0;
-               if (mmc_blk_reset(md, card->host, type))
-                       mqrq->retries = MMC_NO_RETRIES;
-               else
-                       mqrq->retries = MMC_MAX_RETRIES - 1;
-               break;
-       case MMC_BLK_DATA_ERR: {
-               int err;
+       /*
+        * Nothing more to do after the number of bytes transferred has been
+        * updated and there is no card.
+        */
+       if (err && mmc_detect_card_removed(card->host))
+               return;
 
-               /*
-                * Do not accept bytes_xfered, but try to reset. If
-                * reset succeeds, try once more. If reset fails with
-                * ENODEV which means the partition is wrong, then error
-                * out the request. Otherwise attempt to read one sector
-                * at a time.
-                */
-               brq->data.bytes_xfered = 0;
-               err = mmc_blk_reset(md, card->host, type);
-               if (!err) {
-                       mqrq->retries = MMC_MAX_RETRIES - 1;
-                       break;
-               }
-               if (err == -ENODEV) {
-                       mqrq->retries = MMC_NO_RETRIES;
-                       break;
-               }
-               /* Fall through */
+       /* Try to get back to "tran" state */
+       if (!mmc_host_is_spi(mq->card->host) &&
+           (err || !mmc_blk_in_tran_state(status)))
+               err = mmc_blk_fix_state(mq->card, req);
+
+       /*
+        * Special case for SD cards where the card might record the number of
+        * blocks written.
+        */
+       if (!err && mmc_blk_cmd_started(brq) && mmc_card_sd(card) &&
+           rq_data_dir(req) == WRITE) {
+               if (mmc_sd_num_wr_blocks(card, &blocks))
+                       brq->data.bytes_xfered = 0;
+               else
+                       brq->data.bytes_xfered = blocks << 9;
        }
-       case MMC_BLK_ECC_ERR:
-               /*
-                * Do not accept bytes_xfered. If reading more than one
-                * sector, try reading one sector at a time.
-                */
-               brq->data.bytes_xfered = 0;
-               /* FIXME: Missing single sector read for large sector size */
-               if (brq->data.blocks > 1 && !mmc_large_sector(card)) {
-                       /* Redo read one sector at a time */
-                       pr_warn("%s: retrying using single block read\n",
-                               req->rq_disk->disk_name);
-                       mmc_blk_ss_read(mq, req);
-               } else {
-                       mqrq->retries = MMC_NO_RETRIES;
-               }
-               break;
-       case MMC_BLK_NOMEDIUM:
-               /* Do not accept bytes_xfered. Error out the request */
-               brq->data.bytes_xfered = 0;
-               mqrq->retries = MMC_NO_RETRIES;
-               break;
-       default:
-               /* Do not accept bytes_xfered. Error out the request */
-               brq->data.bytes_xfered = 0;
+
+       /* Reset if the card is in a bad state */
+       if (!mmc_host_is_spi(mq->card->host) &&
+           err && mmc_blk_reset(md, card->host, type)) {
+               pr_err("%s: recovery failed!\n", req->rq_disk->disk_name);
                mqrq->retries = MMC_NO_RETRIES;
-               pr_err("%s: Unhandled return value (%d)",
-                      req->rq_disk->disk_name, status);
-               break;
+               return;
+       }
+
+       /*
+        * If anything was done, just return and if there is anything remaining
+        * on the request it will get requeued.
+        */
+       if (brq->data.bytes_xfered)
+               return;
+
+       /* Reset before last retry */
+       if (mqrq->retries + 1 == MMC_MAX_RETRIES)
+               mmc_blk_reset(md, card->host, type);
+
+       /* Command errors fail fast, so use all MMC_MAX_RETRIES */
+       if (brq->sbc.error || brq->cmd.error)
+               return;
+
+       /* Reduce the remaining retries for data errors */
+       if (mqrq->retries < MMC_MAX_RETRIES - MMC_DATA_RETRIES) {
+               mqrq->retries = MMC_MAX_RETRIES - MMC_DATA_RETRIES;
+               return;
+       }
+
+       /* FIXME: Missing single sector read for large sector size */
+       if (rq_data_dir(req) == READ && !mmc_large_sector(card)) {
+               /* Read one sector at a time */
+               mmc_blk_ss_read(mq, req);
+               return;
        }
 }
 
@@ -2165,16 +2192,6 @@ static inline bool mmc_blk_rq_error(struct 
mmc_blk_request *brq)
               brq->data.error || brq->cmd.resp[0] & CMD_ERRORS;
 }
 
-static inline bool mmc_blk_oor_valid(struct mmc_blk_request *brq)
-{
-       return !!brq->mrq.sbc;
-}
-
-static inline u32 mmc_blk_stop_err_bits(struct mmc_blk_request *brq)
-{
-       return mmc_blk_oor_valid(brq) ? CMD_ERRORS : CMD_ERRORS_EXCL_OOR;
-}
-
 static int mmc_blk_card_busy(struct mmc_card *card, struct request *req)
 {
        struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
-- 
1.9.1

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