This patch implement hw_reset function for DesignWare
MMC controller. By adding this feature, mmc blk can
do some basic recovery if emmc device cannot work any
more for unknown reasons.
Signed-off-by: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
---
drivers/mmc/host/dw_mmc.c | 29 +++++++++++++++++++++++++++++
drivers/mmc/host/dw_mmc.h | 4 ++++
2 files changed, 33 insertions(+)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 6e600e8..8a0f2995 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1478,6 +1478,34 @@ static int dw_mci_get_cd(struct mmc_host *mmc)
return present;
}
+static void dw_mci_hw_reset(struct mmc_host *mmc)
+{
+ struct dw_mci_slot *slot = mmc_priv(mmc);
+ struct dw_mci *host = slot->host;
+
+ if (host->use_dma == TRANS_MODE_IDMAC)
+ dw_mci_idmac_reset(host);
+
+ if (!dw_mci_ctrl_reset(host, SDMMC_CTRL_DMA_RESET) ||
+ (!dw_mci_ctrl_reset(host, SDMMC_CTRL_FIFO_RESET)))
+ return;
+
+ /* CARD_RESET
+ * According to eMMC spec
+ * tRstW >= 1us: RST_n pulse width
+ * tRSCA >= 200us: RST_n to Command time
+ * tRSTH >= 1us: RST_n high period
+ * Note: add some margin to make rst timing not too
+ * "spec" for some bad qulity eMMC devices.
+ */
+ mci_writel(slot->host, RST_N, SDMMC_RST_HWRESET);
+ wmb(); /* drain writebuffer */
+ usleep_range(5, 10);
+ mci_writel(slot->host, RST_N, SDMMC_RST_HWACTIVE);
+ wmb(); /* drain writebuffer */
+ usleep_range(500, 1000);
+}
+
static void dw_mci_init_card(struct mmc_host *mmc, struct mmc_card *card)
{
struct dw_mci_slot *slot = mmc_priv(mmc);
@@ -1564,6 +1592,7 @@ static const struct mmc_host_ops dw_mci_ops = {
.set_ios = dw_mci_set_ios,
.get_ro = dw_mci_get_ro,
.get_cd = dw_mci_get_cd,
+ .hw_reset = dw_mci_hw_reset,
.enable_sdio_irq = dw_mci_enable_sdio_irq,
.execute_tuning = dw_mci_execute_tuning,
.card_busy = dw_mci_card_busy,
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index f2a88d4..9df18c1 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -46,6 +46,7 @@
#define SDMMC_VERID 0x06c
#define SDMMC_HCON 0x070
#define SDMMC_UHS_REG 0x074
+#define SDMMC_RST_N 0x078
#define SDMMC_BMOD 0x080
#define SDMMC_PLDMND 0x084
#define SDMMC_DBADDR 0x088
@@ -169,6 +170,9 @@
#define SDMMC_IDMAC_ENABLE BIT(7)
#define SDMMC_IDMAC_FB BIT(1)
#define SDMMC_IDMAC_SWRESET BIT(0)
+/* H/W reset*/
+#define SDMMC_RST_HWACTIVE 0x1
+#define SDMMC_RST_HWRESET 0x0
/* Version ID register define */
#define SDMMC_GET_VERID(x) ((x) & 0xFFFF)
/* Card read threshold */
--
2.3.7
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