[PATCH v6 3/4] mmc: sdhci-tegra: Issue CMD and DAT resets together

[Prathamesh Shete]

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@xxxxxxxxxx>
Signed-off-by: Prathamesh Shete <pshete@xxxxxxxxxx>
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
 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 60ce3e80f248..283f702b4993 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -1535,7 +1535,8 @@ 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 2b5dda521b0e..8512a69f1aae 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 d750c464bd1e..6a5766774b05 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 */
-- 
2.17.1