[PATCH v13 6/6] mmc: sdhci-tegra: Issue CMD and DAT resets together

[Thierry Reding <thierry.reding@gmail.com>]

From: Prathamesh Shete <pshete@nvidia.com>

In case of error condition to avoid system crash Tegra SDMMC controller
requires CMD and DAT resets issued together. SDHCI controller FSM goes
into bad state due to rapid SD card hot-plug event. Issuing reset on the
CMD FSM before DATA FSM results in kernel panic, hence add support to
issue CMD and DAT resets together.

This is applicable to Tegra186 and later chips.

Signed-off-by: Aniruddha TVS Rao <anrao@nvidia.com>
Signed-off-by: Prathamesh Shete <pshete@nvidia.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Thierry Reding <treding@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
---
 drivers/mmc/host/sdhci-tegra.c | 3 ++-
 drivers/mmc/host/sdhci.c       | 5 +++++
 drivers/mmc/host/sdhci.h       | 2 ++
 3 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index fb3823c87cb8..4c2563b27ed6 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -1528,7 +1528,8 @@ static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
 		  SDHCI_QUIRK_NO_HISPD_BIT |
 		  SDHCI_QUIRK_BROKEN_ADMA_ZEROLEN_DESC |
 		  SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
-	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
+	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN |
+		   SDHCI_QUIRK2_ISSUE_CMD_DAT_RESET_TOGETHER,
 	.ops  = &tegra186_sdhci_ops,
 };
 
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index df1c1d10a338..81f4fed11629 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -270,6 +270,11 @@ enum sdhci_reset_reason {
 
 static void sdhci_reset_for_reason(struct sdhci_host *host, enum sdhci_reset_reason reason)
 {
+	if (host->quirks2 & SDHCI_QUIRK2_ISSUE_CMD_DAT_RESET_TOGETHER) {
+		sdhci_do_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
+		return;
+	}
+
 	switch (reason) {
 	case SDHCI_RESET_FOR_INIT:
 		sdhci_do_reset(host, SDHCI_RESET_CMD | SDHCI_RESET_DATA);
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index b6f31a7d6152..605eaee805f7 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -478,6 +478,8 @@ struct sdhci_host {
  * block count.
  */
 #define SDHCI_QUIRK2_USE_32BIT_BLK_CNT			(1<<18)
+/* Issue CMD and DATA reset together */
+#define SDHCI_QUIRK2_ISSUE_CMD_DAT_RESET_TOGETHER	(1<<19)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */
-- 
2.38.1