Date:   Wed, 29 Nov 2017 15:41:15 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     linux-mmc <linux-mmc@...r.kernel.org>,
        linux-block <linux-block@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Bough Chen <haibo.chen@....com>,
        Alex Lemberg <alex.lemberg@...disk.com>,
        Mateusz Nowak <mateusz.nowak@...el.com>,
        Yuliy Izrailov <Yuliy.Izrailov@...disk.com>,
        Jaehoon Chung <jh80.chung@...sung.com>,
        Dong Aisheng <dongas86@...il.com>,
        Das Asutosh <asutoshd@...eaurora.org>,
        Zhangfei Gao <zhangfei.gao@...il.com>,
        Sahitya Tummala <stummala@...eaurora.org>,
        Harjani Ritesh <riteshh@...eaurora.org>,
        Venu Byravarasu <vbyravarasu@...dia.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Christoph Hellwig <hch@....de>
Subject: [PATCH V15 18/22] mmc: block: blk-mq: Stop using legacy recovery

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.hunter@...el.com>
---
 drivers/mmc/core/block.c | 304 +++++++++++++++++++++++++----------------------
 1 file changed, 161 insertions(+), 143 deletions(-)

diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 9d323ed34f82..bd7ead343500 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1557,9 +1557,11 @@ 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;
@@ -1665,15 +1667,6 @@ 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)
@@ -1999,8 +1992,39 @@ 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)
 
+static int mmc_blk_send_stop(struct mmc_card *card, unsigned int timeout)
+{
+	struct mmc_command cmd = {
+		.opcode = MMC_STOP_TRANSMISSION,
+		.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC,
+		/* Some hosts wait for busy anyway, so provide a busy timeout */
+		.busy_timeout = timeout,
+	};
+
+	return mmc_wait_for_cmd(card->host, &cmd, 5);
+}
+
+static int mmc_blk_fix_state(struct mmc_card *card, struct request *req)
+{
+	struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+	struct mmc_blk_request *brq = &mqrq->brq;
+	unsigned int timeout = mmc_blk_data_timeout_ms(card->host, &brq->data);
+	int err;
+
+	mmc_retune_hold_now(card->host);
+
+	mmc_blk_send_stop(card, timeout);
+
+	err = card_busy_detect(card, timeout, false, req, NULL);
+
+	mmc_retune_release(card->host);
+
+	return err;
+}
+
 #define MMC_READ_SINGLE_RETRIES	2
 
 /* Single sector read during recovery */
@@ -2012,7 +2036,6 @@ static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
 	struct mmc_host *host = card->host;
 	blk_status_t error = BLK_STS_OK;
 	int retries = 0;
-	unsigned int timeout = mmc_blk_data_timeout_ms(host, mrq->data);
 
 	do {
 		u32 status;
@@ -2027,12 +2050,8 @@ static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
 			goto error_exit;
 
 		if (!mmc_host_is_spi(host) &&
-		    R1_CURRENT_STATE(status) != R1_STATE_TRAN) {
-			u32 stop_status = 0;
-			bool gen_err = false;
-
-			err = send_stop(card, timeout, req, &gen_err,
-					&stop_status);
+		    !mmc_blk_in_tran_state(status)) {
+			err = mmc_blk_fix_state(card, req);
 			if (err)
 				goto error_exit;
 		}
@@ -2062,6 +2081,60 @@ static void mmc_blk_read_single(struct mmc_queue *mq, struct request *req)
 		mqrq->retries = MMC_MAX_RETRIES - 1;
 }
 
+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);
+}
+
+/*
+ * 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;
@@ -2069,131 +2142,86 @@ 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_read_single(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 (!mmc_large_sector(card) && rq_data_dir(req) == READ &&
+	    brq->data.blocks > 1) {
+		/* Read one sector at a time */
+		mmc_blk_read_single(mq, req);
+		return;
 	}
 }
 
@@ -2205,16 +2233,6 @@ 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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