mmc: sdhci: Fix recovery from tuning timeout

commit 61e53bd0047d58caee0c7170613045bf96de4458 upstream.

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>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 7f80d185a5cce68684bf5a34f04fd8da8ccd7680..e1e274a0a34f7246448a567c336915049c713121 100644 (file)
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2091,7 +2091,27 @@ 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;
                }