[PATCH V2 0/9] mmc: sdhci: Fix recovery from tuning timeout

[PATCH V2 0/9] mmc: sdhci: Fix recovery from tuning timeout

[Adrian Hunter]

Hi

Here are some small SDHCI tuning-related fixes and some clean-ups.

Changes in V2:
	Added clean-up patches


Adrian Hunter (9):
      Revert "mmc: sdhci: Reset cmd and data circuits after tuning failure"
      mmc: sdhci: Fix recovery from tuning timeout
      mmc: sdhci: Fix tuning reset after exhausting the maximum number of loops
      mmc: sdhci: Always allow tuning to fall back to fixed sampling
      mmc: mmc: Introduce mmc_abort_tuning()
      mmc: sdhci: Use mmc_abort_tuning()
      mmc: sdhci: Factor out tuning helper functions
      mmc: sdhci: Simplify tuning block size logic
      mmc: sdhci: Tidy tuning loop

 drivers/mmc/core/mmc_ops.c |  25 ++++
 drivers/mmc/host/sdhci.c   | 278 ++++++++++++++++++++++++---------------------
 include/linux/mmc/core.h   |   1 +
 3 files changed, 173 insertions(+), 131 deletions(-)


Regards
Adrian

[PATCH V2 1/9] Revert "mmc: sdhci: Reset cmd and data circuits after tuning failure"

[Adrian Hunter]

This reverts commit fe5fb2e3b58f ("mmc: sdhci: Reset cmd and data circuits
after tuning failure").

A better fix is available, and it will be applied to older stable releases,
so get this out of the way by reverting it.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: stable@vger.kernel.org # v4.9+
---
 drivers/mmc/host/sdhci.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 7f2526c9572f..e761fe2aa99e 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2090,10 +2090,6 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 
 		if (!host->tuning_done) {
 			pr_info(DRIVER_NAME ": Timeout waiting for Buffer Read Ready interrupt during tuning procedure, falling back to fixed sampling clock\n");
-
-			sdhci_do_reset(host, SDHCI_RESET_CMD);
-			sdhci_do_reset(host, SDHCI_RESET_DATA);
-
 			ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
 			ctrl &= ~SDHCI_CTRL_TUNED_CLK;
 			ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
-- 
1.9.1

[PATCH V2 2/9] mmc: sdhci: Fix recovery from tuning timeout

[Adrian Hunter]

Clearing the tuning bits should reset the tuning circuit. However there is
more to do. Reset the command and data lines for good measure, and then
for eMMC ensure the card is not still trying to process a tuning command by
sending a stop command.

Note the JEDEC eMMC specification says the stop command (CMD12) can be used
to stop a tuning command (CMD21) whereas the SD specification is silent on
the subject with respect to the SD tuning command (CMD19). Considering that
CMD12 is not a valid SDIO command, the stop command is sent only when the
tuning command is CMD21 i.e. for eMMC. That addresses cases seen so far
which have been on eMMC.

Note that this replaces the commit fe5fb2e3b58f ("mmc: sdhci: Reset cmd and
data circuits after tuning failure") which is being reverted for v4.9+.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Dan O'Donovan <dan@emutex.com>
Cc: stable@vger.kernel.org
---
 drivers/mmc/host/sdhci.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index e761fe2aa99e..1d72a51287d4 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2095,7 +2095,27 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 			ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
 			sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
 
+			sdhci_do_reset(host, SDHCI_RESET_CMD);
+			sdhci_do_reset(host, SDHCI_RESET_DATA);
+
 			err = -EIO;
+
+			if (cmd.opcode != MMC_SEND_TUNING_BLOCK_HS200)
+				goto out;
+
+			sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
+			sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+
+			spin_unlock_irqrestore(&host->lock, flags);
+
+			memset(&cmd, 0, sizeof(cmd));
+			cmd.opcode = MMC_STOP_TRANSMISSION;
+			cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
+			cmd.busy_timeout = 50;
+			mmc_wait_for_cmd(mmc, &cmd, 0);
+
+			spin_lock_irqsave(&host->lock, flags);
+
 			goto out;
 		}
 
-- 
1.9.1

[PATCH V2 3/9] mmc: sdhci: Fix tuning reset after exhausting the maximum number of loops

[Adrian Hunter]

If the driver has exhausted the maximum number of tuning loops, then fixed
sampling is used. To do that both SDHCI_CTRL_TUNED_CLK and
SDHCI_CTRL_EXEC_TUNING must be reset to 0, but only SDHCI_CTRL_TUNED_CLK
was being reset. Reset SDHCI_CTRL_EXEC_TUNING to 0 also.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/host/sdhci.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1d72a51287d4..ad2f2c6113e4 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2134,6 +2134,7 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	 */
 	if (tuning_loop_counter < 0) {
 		ctrl &= ~SDHCI_CTRL_TUNED_CLK;
+		ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
 		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
 	}
 	if (!(ctrl & SDHCI_CTRL_TUNED_CLK)) {
-- 
1.9.1

[PATCH V2 4/9] mmc: sdhci: Always allow tuning to fall back to fixed sampling

[Adrian Hunter]

SDHCI falls back to fixed sampling if there is an error during tuning.
However it also reports an error unless there is periodic re-tuning.
That is not the best option because:
a) there is a reasonable chance that fixed sampling will work, especially
at room temperature.
b) re-tuning will be done again anyway if there are CRC errors.
Change to return no error always when falling back to fixed sampling.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/host/sdhci.c | 20 ++------------------
 1 file changed, 2 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index ad2f2c6113e4..a23887799f43 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2098,8 +2098,6 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 			sdhci_do_reset(host, SDHCI_RESET_CMD);
 			sdhci_do_reset(host, SDHCI_RESET_DATA);
 
-			err = -EIO;
-
 			if (cmd.opcode != MMC_SEND_TUNING_BLOCK_HS200)
 				goto out;
 
@@ -2137,24 +2135,10 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 		ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
 		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
 	}
-	if (!(ctrl & SDHCI_CTRL_TUNED_CLK)) {
+	if (!(ctrl & SDHCI_CTRL_TUNED_CLK))
 		pr_info(DRIVER_NAME ": Tuning procedure failed, falling back to fixed sampling clock\n");
-		err = -EIO;
-	}
-
 out:
-	if (tuning_count) {
-		/*
-		 * In case tuning fails, host controllers which support
-		 * re-tuning can try tuning again at a later time, when the
-		 * re-tuning timer expires.  So for these controllers, we
-		 * return 0. Since there might be other controllers who do not
-		 * have this capability, we return error for them.
-		 */
-		err = 0;
-	}
-
-	host->mmc->retune_period = err ? 0 : tuning_count;
+	host->mmc->retune_period = tuning_count;
 
 	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
 	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
-- 
1.9.1

[PATCH V2 5/9] mmc: mmc: Introduce mmc_abort_tuning()

[Adrian Hunter]

If a tuning command times out, the card could still be processing it, which
will cause problems for recovery. The eMMC specification says that CMD12
can be used to stop CMD21, so add a function that does that.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/core/mmc_ops.c | 25 +++++++++++++++++++++++++
 include/linux/mmc/core.h   |  1 +
 2 files changed, 26 insertions(+)

diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
index 81ce63bb0773..b11c3455b040 100644
--- a/drivers/mmc/core/mmc_ops.c
+++ b/drivers/mmc/core/mmc_ops.c
@@ -678,6 +678,31 @@ int mmc_send_tuning(struct mmc_host *host, u32 opcode, int *cmd_error)
 }
 EXPORT_SYMBOL_GPL(mmc_send_tuning);
 
+int mmc_abort_tuning(struct mmc_host *host, u32 opcode)
+{
+	struct mmc_command cmd = {0};
+
+	/*
+	 * eMMC specification specifies that CMD12 can be used to stop a tuning
+	 * command, but SD specification does not, so do nothing unless it is
+	 * eMMC.
+	 */
+	if (opcode != MMC_SEND_TUNING_BLOCK_HS200)
+		return 0;
+
+	cmd.opcode = MMC_STOP_TRANSMISSION;
+	cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R1 | MMC_CMD_AC;
+
+	/*
+	 * For drivers that override R1 to R1b, set an arbitrary timeout based
+	 * on the tuning timeout i.e. 150ms.
+	 */
+	cmd.busy_timeout = 150;
+
+	return mmc_wait_for_cmd(host, &cmd, 0);
+}
+EXPORT_SYMBOL_GPL(mmc_abort_tuning);
+
 static int
 mmc_send_bus_test(struct mmc_card *card, struct mmc_host *host, u8 opcode,
 		  u8 len)
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 0ce928b3ce90..e33cc748dcfe 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -176,6 +176,7 @@ extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *,
 extern void mmc_start_bkops(struct mmc_card *card, bool from_exception);
 extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
 extern int mmc_send_tuning(struct mmc_host *host, u32 opcode, int *cmd_error);
+extern int mmc_abort_tuning(struct mmc_host *host, u32 opcode);
 extern int mmc_get_ext_csd(struct mmc_card *card, u8 **new_ext_csd);
 
 #define MMC_ERASE_ARG		0x00000000
-- 
1.9.1

[PATCH V2 6/9] mmc: sdhci: Use mmc_abort_tuning()

[Adrian Hunter]

Use mmc_abort_tuning() instead of open-coding the stop command.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/host/sdhci.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index a23887799f43..b841d0a57af1 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2098,20 +2098,11 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 			sdhci_do_reset(host, SDHCI_RESET_CMD);
 			sdhci_do_reset(host, SDHCI_RESET_DATA);
 
-			if (cmd.opcode != MMC_SEND_TUNING_BLOCK_HS200)
-				goto out;
-
 			sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
 			sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
 
 			spin_unlock_irqrestore(&host->lock, flags);
-
-			memset(&cmd, 0, sizeof(cmd));
-			cmd.opcode = MMC_STOP_TRANSMISSION;
-			cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
-			cmd.busy_timeout = 50;
-			mmc_wait_for_cmd(mmc, &cmd, 0);
-
+			mmc_abort_tuning(mmc, opcode);
 			spin_lock_irqsave(&host->lock, flags);
 
 			goto out;
-- 
1.9.1

[PATCH V2 7/9] mmc: sdhci: Factor out tuning helper functions

[Adrian Hunter]

Factor out some functions to tidy up the code in sdhci_execute_tuning.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/host/sdhci.c | 209 ++++++++++++++++++++++++++---------------------
 1 file changed, 117 insertions(+), 92 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index b841d0a57af1..fa89870a690b 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1952,6 +1952,115 @@ static int sdhci_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_ios *ios)
 	return 0;
 }
 
+static void sdhci_start_tuning(struct sdhci_host *host)
+{
+	u16 ctrl;
+
+	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+	ctrl |= SDHCI_CTRL_EXEC_TUNING;
+	if (host->quirks2 & SDHCI_QUIRK2_TUNING_WORK_AROUND)
+		ctrl |= SDHCI_CTRL_TUNED_CLK;
+	sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+
+	/*
+	 * As per the Host Controller spec v3.00, tuning command
+	 * generates Buffer Read Ready interrupt, so enable that.
+	 *
+	 * Note: The spec clearly says that when tuning sequence
+	 * is being performed, the controller does not generate
+	 * interrupts other than Buffer Read Ready interrupt. But
+	 * to make sure we don't hit a controller bug, we _only_
+	 * enable Buffer Read Ready interrupt here.
+	 */
+	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_INT_ENABLE);
+	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_SIGNAL_ENABLE);
+}
+
+static void sdhci_end_tuning(struct sdhci_host *host)
+{
+	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
+	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+}
+
+static void sdhci_reset_tuning(struct sdhci_host *host)
+{
+	u16 ctrl;
+
+	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+	ctrl &= ~SDHCI_CTRL_TUNED_CLK;
+	ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
+	sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+}
+
+static void sdhci_abort_tuning(struct sdhci_host *host, u32 opcode,
+			       unsigned long flags)
+{
+	sdhci_reset_tuning(host);
+
+	sdhci_do_reset(host, SDHCI_RESET_CMD);
+	sdhci_do_reset(host, SDHCI_RESET_DATA);
+
+	sdhci_end_tuning(host);
+
+	spin_unlock_irqrestore(&host->lock, flags);
+	mmc_abort_tuning(host->mmc, opcode);
+	spin_lock_irqsave(&host->lock, flags);
+}
+
+static void sdhci_send_tuning(struct sdhci_host *host, u32 opcode,
+			      unsigned long flags)
+{
+	struct mmc_host *mmc = host->mmc;
+	struct mmc_command cmd = {0};
+	struct mmc_request mrq = {NULL};
+
+	cmd.opcode = opcode;
+	cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+	cmd.mrq = &mrq;
+
+	mrq.cmd = &cmd;
+	/*
+	 * In response to CMD19, the card sends 64 bytes of tuning
+	 * block to the Host Controller. So we set the block size
+	 * to 64 here.
+	 */
+	if (cmd.opcode == MMC_SEND_TUNING_BLOCK_HS200) {
+		if (mmc->ios.bus_width == MMC_BUS_WIDTH_8)
+			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 128),
+				     SDHCI_BLOCK_SIZE);
+		else if (mmc->ios.bus_width == MMC_BUS_WIDTH_4)
+			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
+				     SDHCI_BLOCK_SIZE);
+	} else {
+		sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
+			     SDHCI_BLOCK_SIZE);
+	}
+
+	/*
+	 * The tuning block is sent by the card to the host controller.
+	 * So we set the TRNS_READ bit in the Transfer Mode register.
+	 * This also takes care of setting DMA Enable and Multi Block
+	 * Select in the same register to 0.
+	 */
+	sdhci_writew(host, SDHCI_TRNS_READ, SDHCI_TRANSFER_MODE);
+
+	sdhci_send_command(host, &cmd);
+
+	host->cmd = NULL;
+
+	sdhci_del_timer(host, &mrq);
+
+	host->tuning_done = 0;
+
+	spin_unlock_irqrestore(&host->lock, flags);
+
+	/* Wait for Buffer Read Ready interrupt */
+	wait_event_timeout(host->buf_ready_int, (host->tuning_done == 1),
+			   msecs_to_jiffies(50));
+
+	spin_lock_irqsave(&host->lock, flags);
+}
+
 static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
@@ -2011,105 +2120,24 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 		return err;
 	}
 
-	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-	ctrl |= SDHCI_CTRL_EXEC_TUNING;
-	if (host->quirks2 & SDHCI_QUIRK2_TUNING_WORK_AROUND)
-		ctrl |= SDHCI_CTRL_TUNED_CLK;
-	sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
-
-	/*
-	 * As per the Host Controller spec v3.00, tuning command
-	 * generates Buffer Read Ready interrupt, so enable that.
-	 *
-	 * Note: The spec clearly says that when tuning sequence
-	 * is being performed, the controller does not generate
-	 * interrupts other than Buffer Read Ready interrupt. But
-	 * to make sure we don't hit a controller bug, we _only_
-	 * enable Buffer Read Ready interrupt here.
-	 */
-	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_INT_ENABLE);
-	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_SIGNAL_ENABLE);
+	sdhci_start_tuning(host);
 
 	/*
 	 * Issue CMD19 repeatedly till Execute Tuning is set to 0 or the number
 	 * of loops reaches 40 times.
 	 */
 	do {
-		struct mmc_command cmd = {0};
-		struct mmc_request mrq = {NULL};
-
-		cmd.opcode = opcode;
-		cmd.arg = 0;
-		cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
-		cmd.retries = 0;
-		cmd.data = NULL;
-		cmd.mrq = &mrq;
-		cmd.error = 0;
-
 		if (tuning_loop_counter-- == 0)
 			break;
 
-		mrq.cmd = &cmd;
-
-		/*
-		 * In response to CMD19, the card sends 64 bytes of tuning
-		 * block to the Host Controller. So we set the block size
-		 * to 64 here.
-		 */
-		if (cmd.opcode == MMC_SEND_TUNING_BLOCK_HS200) {
-			if (mmc->ios.bus_width == MMC_BUS_WIDTH_8)
-				sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 128),
-					     SDHCI_BLOCK_SIZE);
-			else if (mmc->ios.bus_width == MMC_BUS_WIDTH_4)
-				sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
-					     SDHCI_BLOCK_SIZE);
-		} else {
-			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
-				     SDHCI_BLOCK_SIZE);
-		}
-
-		/*
-		 * The tuning block is sent by the card to the host controller.
-		 * So we set the TRNS_READ bit in the Transfer Mode register.
-		 * This also takes care of setting DMA Enable and Multi Block
-		 * Select in the same register to 0.
-		 */
-		sdhci_writew(host, SDHCI_TRNS_READ, SDHCI_TRANSFER_MODE);
-
-		sdhci_send_command(host, &cmd);
-
-		host->cmd = NULL;
-		sdhci_del_timer(host, &mrq);
-
-		spin_unlock_irqrestore(&host->lock, flags);
-		/* Wait for Buffer Read Ready interrupt */
-		wait_event_timeout(host->buf_ready_int,
-					(host->tuning_done == 1),
-					msecs_to_jiffies(50));
-		spin_lock_irqsave(&host->lock, flags);
+		sdhci_send_tuning(host, opcode, flags);
 
 		if (!host->tuning_done) {
 			pr_info(DRIVER_NAME ": Timeout waiting for Buffer Read Ready interrupt during tuning procedure, falling back to fixed sampling clock\n");
-			ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-			ctrl &= ~SDHCI_CTRL_TUNED_CLK;
-			ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
-			sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
-
-			sdhci_do_reset(host, SDHCI_RESET_CMD);
-			sdhci_do_reset(host, SDHCI_RESET_DATA);
-
-			sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
-			sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
-
-			spin_unlock_irqrestore(&host->lock, flags);
-			mmc_abort_tuning(mmc, opcode);
-			spin_lock_irqsave(&host->lock, flags);
-
+			sdhci_abort_tuning(host, opcode, flags);
 			goto out;
 		}
 
-		host->tuning_done = 0;
-
 		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
 
 		/* eMMC spec does not require a delay between tuning cycles */
@@ -2121,18 +2149,15 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	 * The Host Driver has exhausted the maximum number of loops allowed,
 	 * so use fixed sampling frequency.
 	 */
-	if (tuning_loop_counter < 0) {
-		ctrl &= ~SDHCI_CTRL_TUNED_CLK;
-		ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
-		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
-	}
-	if (!(ctrl & SDHCI_CTRL_TUNED_CLK))
+	if (tuning_loop_counter < 0)
+		sdhci_reset_tuning(host);
+
+	if (tuning_loop_counter < 0 || !(ctrl & SDHCI_CTRL_TUNED_CLK))
 		pr_info(DRIVER_NAME ": Tuning procedure failed, falling back to fixed sampling clock\n");
 out:
 	host->mmc->retune_period = tuning_count;
 
-	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
-	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+	sdhci_end_tuning(host);
 out_unlock:
 	spin_unlock_irqrestore(&host->lock, flags);
 	return err;
-- 
1.9.1

[PATCH V3 7/9] mmc: sdhci: Factor out tuning helper functions

[Adrian Hunter]

Factor out some functions to tidy up the code in sdhci_execute_tuning.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---


Changes in V3:

  Add comment about why mmc_send_tuning() is not used.


 drivers/mmc/host/sdhci.c | 216 +++++++++++++++++++++++++++--------------------
 1 file changed, 124 insertions(+), 92 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index b841d0a57af1..a6f8e164b3fd 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1952,6 +1952,122 @@ static int sdhci_prepare_hs400_tuning(struct mmc_host *mmc, struct mmc_ios *ios)
 	return 0;
 }
 
+static void sdhci_start_tuning(struct sdhci_host *host)
+{
+	u16 ctrl;
+
+	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+	ctrl |= SDHCI_CTRL_EXEC_TUNING;
+	if (host->quirks2 & SDHCI_QUIRK2_TUNING_WORK_AROUND)
+		ctrl |= SDHCI_CTRL_TUNED_CLK;
+	sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+
+	/*
+	 * As per the Host Controller spec v3.00, tuning command
+	 * generates Buffer Read Ready interrupt, so enable that.
+	 *
+	 * Note: The spec clearly says that when tuning sequence
+	 * is being performed, the controller does not generate
+	 * interrupts other than Buffer Read Ready interrupt. But
+	 * to make sure we don't hit a controller bug, we _only_
+	 * enable Buffer Read Ready interrupt here.
+	 */
+	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_INT_ENABLE);
+	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_SIGNAL_ENABLE);
+}
+
+static void sdhci_end_tuning(struct sdhci_host *host)
+{
+	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
+	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+}
+
+static void sdhci_reset_tuning(struct sdhci_host *host)
+{
+	u16 ctrl;
+
+	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+	ctrl &= ~SDHCI_CTRL_TUNED_CLK;
+	ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
+	sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
+}
+
+static void sdhci_abort_tuning(struct sdhci_host *host, u32 opcode,
+			       unsigned long flags)
+{
+	sdhci_reset_tuning(host);
+
+	sdhci_do_reset(host, SDHCI_RESET_CMD);
+	sdhci_do_reset(host, SDHCI_RESET_DATA);
+
+	sdhci_end_tuning(host);
+
+	spin_unlock_irqrestore(&host->lock, flags);
+	mmc_abort_tuning(host->mmc, opcode);
+	spin_lock_irqsave(&host->lock, flags);
+}
+
+/*
+ * We use sdhci_send_tuning() because mmc_send_tuning() is not a good fit. SDHCI
+ * tuning command does not have a data payload (or rather the hardware does it
+ * automatically) so mmc_send_tuning() will return -EIO. Also the tuning command
+ * interrupt setup is different to other commands and there is no timeout
+ * interrupt so special handling is needed.
+ */
+static void sdhci_send_tuning(struct sdhci_host *host, u32 opcode,
+			      unsigned long flags)
+{
+	struct mmc_host *mmc = host->mmc;
+	struct mmc_command cmd = {0};
+	struct mmc_request mrq = {NULL};
+
+	cmd.opcode = opcode;
+	cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
+	cmd.mrq = &mrq;
+
+	mrq.cmd = &cmd;
+	/*
+	 * In response to CMD19, the card sends 64 bytes of tuning
+	 * block to the Host Controller. So we set the block size
+	 * to 64 here.
+	 */
+	if (cmd.opcode == MMC_SEND_TUNING_BLOCK_HS200) {
+		if (mmc->ios.bus_width == MMC_BUS_WIDTH_8)
+			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 128),
+				     SDHCI_BLOCK_SIZE);
+		else if (mmc->ios.bus_width == MMC_BUS_WIDTH_4)
+			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
+				     SDHCI_BLOCK_SIZE);
+	} else {
+		sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
+			     SDHCI_BLOCK_SIZE);
+	}
+
+	/*
+	 * The tuning block is sent by the card to the host controller.
+	 * So we set the TRNS_READ bit in the Transfer Mode register.
+	 * This also takes care of setting DMA Enable and Multi Block
+	 * Select in the same register to 0.
+	 */
+	sdhci_writew(host, SDHCI_TRNS_READ, SDHCI_TRANSFER_MODE);
+
+	sdhci_send_command(host, &cmd);
+
+	host->cmd = NULL;
+
+	sdhci_del_timer(host, &mrq);
+
+	host->tuning_done = 0;
+
+	spin_unlock_irqrestore(&host->lock, flags);
+
+	/* Wait for Buffer Read Ready interrupt */
+	wait_event_timeout(host->buf_ready_int, (host->tuning_done == 1),
+			   msecs_to_jiffies(50));
+
+	spin_lock_irqsave(&host->lock, flags);
+}
+
 static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
@@ -2011,105 +2127,24 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 		return err;
 	}
 
-	ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-	ctrl |= SDHCI_CTRL_EXEC_TUNING;
-	if (host->quirks2 & SDHCI_QUIRK2_TUNING_WORK_AROUND)
-		ctrl |= SDHCI_CTRL_TUNED_CLK;
-	sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
-
-	/*
-	 * As per the Host Controller spec v3.00, tuning command
-	 * generates Buffer Read Ready interrupt, so enable that.
-	 *
-	 * Note: The spec clearly says that when tuning sequence
-	 * is being performed, the controller does not generate
-	 * interrupts other than Buffer Read Ready interrupt. But
-	 * to make sure we don't hit a controller bug, we _only_
-	 * enable Buffer Read Ready interrupt here.
-	 */
-	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_INT_ENABLE);
-	sdhci_writel(host, SDHCI_INT_DATA_AVAIL, SDHCI_SIGNAL_ENABLE);
+	sdhci_start_tuning(host);
 
 	/*
 	 * Issue CMD19 repeatedly till Execute Tuning is set to 0 or the number
 	 * of loops reaches 40 times.
 	 */
 	do {
-		struct mmc_command cmd = {0};
-		struct mmc_request mrq = {NULL};
-
-		cmd.opcode = opcode;
-		cmd.arg = 0;
-		cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
-		cmd.retries = 0;
-		cmd.data = NULL;
-		cmd.mrq = &mrq;
-		cmd.error = 0;
-
 		if (tuning_loop_counter-- == 0)
 			break;
 
-		mrq.cmd = &cmd;
-
-		/*
-		 * In response to CMD19, the card sends 64 bytes of tuning
-		 * block to the Host Controller. So we set the block size
-		 * to 64 here.
-		 */
-		if (cmd.opcode == MMC_SEND_TUNING_BLOCK_HS200) {
-			if (mmc->ios.bus_width == MMC_BUS_WIDTH_8)
-				sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 128),
-					     SDHCI_BLOCK_SIZE);
-			else if (mmc->ios.bus_width == MMC_BUS_WIDTH_4)
-				sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
-					     SDHCI_BLOCK_SIZE);
-		} else {
-			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
-				     SDHCI_BLOCK_SIZE);
-		}
-
-		/*
-		 * The tuning block is sent by the card to the host controller.
-		 * So we set the TRNS_READ bit in the Transfer Mode register.
-		 * This also takes care of setting DMA Enable and Multi Block
-		 * Select in the same register to 0.
-		 */
-		sdhci_writew(host, SDHCI_TRNS_READ, SDHCI_TRANSFER_MODE);
-
-		sdhci_send_command(host, &cmd);
-
-		host->cmd = NULL;
-		sdhci_del_timer(host, &mrq);
-
-		spin_unlock_irqrestore(&host->lock, flags);
-		/* Wait for Buffer Read Ready interrupt */
-		wait_event_timeout(host->buf_ready_int,
-					(host->tuning_done == 1),
-					msecs_to_jiffies(50));
-		spin_lock_irqsave(&host->lock, flags);
+		sdhci_send_tuning(host, opcode, flags);
 
 		if (!host->tuning_done) {
 			pr_info(DRIVER_NAME ": Timeout waiting for Buffer Read Ready interrupt during tuning procedure, falling back to fixed sampling clock\n");
-			ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-			ctrl &= ~SDHCI_CTRL_TUNED_CLK;
-			ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
-			sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
-
-			sdhci_do_reset(host, SDHCI_RESET_CMD);
-			sdhci_do_reset(host, SDHCI_RESET_DATA);
-
-			sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
-			sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
-
-			spin_unlock_irqrestore(&host->lock, flags);
-			mmc_abort_tuning(mmc, opcode);
-			spin_lock_irqsave(&host->lock, flags);
-
+			sdhci_abort_tuning(host, opcode, flags);
 			goto out;
 		}
 
-		host->tuning_done = 0;
-
 		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
 
 		/* eMMC spec does not require a delay between tuning cycles */
@@ -2121,18 +2156,15 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 	 * The Host Driver has exhausted the maximum number of loops allowed,
 	 * so use fixed sampling frequency.
 	 */
-	if (tuning_loop_counter < 0) {
-		ctrl &= ~SDHCI_CTRL_TUNED_CLK;
-		ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
-		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
-	}
-	if (!(ctrl & SDHCI_CTRL_TUNED_CLK))
+	if (tuning_loop_counter < 0)
+		sdhci_reset_tuning(host);
+
+	if (tuning_loop_counter < 0 || !(ctrl & SDHCI_CTRL_TUNED_CLK))
 		pr_info(DRIVER_NAME ": Tuning procedure failed, falling back to fixed sampling clock\n");
 out:
 	host->mmc->retune_period = tuning_count;
 
-	sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
-	sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
+	sdhci_end_tuning(host);
 out_unlock:
 	spin_unlock_irqrestore(&host->lock, flags);
 	return err;
-- 
1.9.1

[PATCH V2 8/9] mmc: sdhci: Simplify tuning block size logic

[Adrian Hunter]

There are only 2 possible block sizes, so simplify 2 if-statements into 1.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/host/sdhci.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index fa89870a690b..e9ff7d005851 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2024,17 +2024,11 @@ static void sdhci_send_tuning(struct sdhci_host *host, u32 opcode,
 	 * block to the Host Controller. So we set the block size
 	 * to 64 here.
 	 */
-	if (cmd.opcode == MMC_SEND_TUNING_BLOCK_HS200) {
-		if (mmc->ios.bus_width == MMC_BUS_WIDTH_8)
-			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 128),
-				     SDHCI_BLOCK_SIZE);
-		else if (mmc->ios.bus_width == MMC_BUS_WIDTH_4)
-			sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
-				     SDHCI_BLOCK_SIZE);
-	} else {
-		sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64),
-			     SDHCI_BLOCK_SIZE);
-	}
+	if (cmd.opcode == MMC_SEND_TUNING_BLOCK_HS200 &&
+	    mmc->ios.bus_width == MMC_BUS_WIDTH_8)
+		sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 128), SDHCI_BLOCK_SIZE);
+	else
+		sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64), SDHCI_BLOCK_SIZE);
 
 	/*
 	 * The tuning block is sent by the card to the host controller.
-- 
1.9.1

[PATCH V2 9/9] mmc: sdhci: Tidy tuning loop

[Adrian Hunter]

Tidy the tuning loop by moving it to a separate function and making it a
for-loop.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
---
 drivers/mmc/host/sdhci.c | 81 +++++++++++++++++++++++++-----------------------
 1 file changed, 43 insertions(+), 38 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index e9ff7d005851..1ac08e1a6211 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2055,11 +2055,47 @@ static void sdhci_send_tuning(struct sdhci_host *host, u32 opcode,
 	spin_lock_irqsave(&host->lock, flags);
 }
 
+static void __sdhci_execute_tuning(struct sdhci_host *host, u32 opcode,
+				   unsigned long flags)
+{
+	int i;
+
+	/*
+	 * Issue opcode repeatedly till Execute Tuning is set to 0 or the number
+	 * of loops reaches 40 times.
+	 */
+	for (i = 0; i < MAX_TUNING_LOOP; i++) {
+		u16 ctrl;
+
+		sdhci_send_tuning(host, opcode, flags);
+
+		if (!host->tuning_done) {
+			pr_info("%s: Tuning timeout, falling back to fixed sampling clock\n",
+				mmc_hostname(host->mmc));
+			sdhci_abort_tuning(host, opcode, flags);
+			return;
+		}
+
+		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
+		if (!(ctrl & SDHCI_CTRL_EXEC_TUNING)) {
+			if (ctrl & SDHCI_CTRL_TUNED_CLK)
+				return; /* Success! */
+			break;
+		}
+
+		/* eMMC spec does not require a delay between tuning cycles */
+		if (opcode == MMC_SEND_TUNING_BLOCK)
+			mdelay(1);
+	}
+
+	pr_info("%s: Tuning failed, falling back to fixed sampling clock\n",
+		mmc_hostname(host->mmc));
+	sdhci_reset_tuning(host);
+}
+
 static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 {
 	struct sdhci_host *host = mmc_priv(mmc);
-	u16 ctrl;
-	int tuning_loop_counter = MAX_TUNING_LOOP;
 	int err = 0;
 	unsigned long flags;
 	unsigned int tuning_count = 0;
@@ -2110,50 +2146,19 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
 
 	if (host->ops->platform_execute_tuning) {
 		spin_unlock_irqrestore(&host->lock, flags);
-		err = host->ops->platform_execute_tuning(host, opcode);
-		return err;
+		return host->ops->platform_execute_tuning(host, opcode);
 	}
 
-	sdhci_start_tuning(host);
-
-	/*
-	 * Issue CMD19 repeatedly till Execute Tuning is set to 0 or the number
-	 * of loops reaches 40 times.
-	 */
-	do {
-		if (tuning_loop_counter-- == 0)
-			break;
-
-		sdhci_send_tuning(host, opcode, flags);
-
-		if (!host->tuning_done) {
-			pr_info(DRIVER_NAME ": Timeout waiting for Buffer Read Ready interrupt during tuning procedure, falling back to fixed sampling clock\n");
-			sdhci_abort_tuning(host, opcode, flags);
-			goto out;
-		}
-
-		ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
-
-		/* eMMC spec does not require a delay between tuning cycles */
-		if (opcode == MMC_SEND_TUNING_BLOCK)
-			mdelay(1);
-	} while (ctrl & SDHCI_CTRL_EXEC_TUNING);
+	host->mmc->retune_period = tuning_count;
 
-	/*
-	 * The Host Driver has exhausted the maximum number of loops allowed,
-	 * so use fixed sampling frequency.
-	 */
-	if (tuning_loop_counter < 0)
-		sdhci_reset_tuning(host);
+	sdhci_start_tuning(host);
 
-	if (tuning_loop_counter < 0 || !(ctrl & SDHCI_CTRL_TUNED_CLK))
-		pr_info(DRIVER_NAME ": Tuning procedure failed, falling back to fixed sampling clock\n");
-out:
-	host->mmc->retune_period = tuning_count;
+	__sdhci_execute_tuning(host, opcode, flags);
 
 	sdhci_end_tuning(host);
 out_unlock:
 	spin_unlock_irqrestore(&host->lock, flags);
+
 	return err;
 }
 
-- 
1.9.1

Re: [PATCH V2 0/9] mmc: sdhci: Fix recovery from tuning timeout

[Ulf Hansson]

On 2 December 2016 at 14:14, Adrian Hunter <adrian.hunter@intel.com> wrote:
> Hi
>
> Here are some small SDHCI tuning-related fixes and some clean-ups.
>
> Changes in V2:
>         Added clean-up patches
>
>
> Adrian Hunter (9):
>       Revert "mmc: sdhci: Reset cmd and data circuits after tuning failure"
>       mmc: sdhci: Fix recovery from tuning timeout
>       mmc: sdhci: Fix tuning reset after exhausting the maximum number of loops
>       mmc: sdhci: Always allow tuning to fall back to fixed sampling
>       mmc: mmc: Introduce mmc_abort_tuning()
>       mmc: sdhci: Use mmc_abort_tuning()
>       mmc: sdhci: Factor out tuning helper functions
>       mmc: sdhci: Simplify tuning block size logic
>       mmc: sdhci: Tidy tuning loop
>
>  drivers/mmc/core/mmc_ops.c |  25 ++++
>  drivers/mmc/host/sdhci.c   | 278 ++++++++++++++++++++++++---------------------
>  include/linux/mmc/core.h   |   1 +
>  3 files changed, 173 insertions(+), 131 deletions(-)
>
>
> Regards
> Adrian

Thanks, applied for next. I also picked v3 of patch 7/9.

Kind regards
Uffe