mmc: dw_mmc: add the card write threshold for HS400 mode

Since v2.80a, dwmmc controller introduced the card write threshold for
HS400 mode. So CardThrCtl can be supported during write operation, not
only read operation.
(Note: Only use the write threshold when mode is HS400.)

To use more compatible, removed "_rd_" from function name.
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/dw_mmc.c

@@ -899,23 +899,35 @@ static void dw_mci_adjust_fifoth(struct dw_mci *host, struct mmc_data *data)
 	mci_writel(host, FIFOTH, fifoth_val);
 }
 
-static void dw_mci_ctrl_rd_thld(struct dw_mci *host, struct mmc_data *data)
+static void dw_mci_ctrl_thld(struct dw_mci *host, struct mmc_data *data)
 {
 	unsigned int blksz = data->blksz;
 	u32 blksz_depth, fifo_depth;
 	u16 thld_size;
-
-	WARN_ON(!(data->flags & MMC_DATA_READ));
+	u8 enable;
 
 	/*
 	 * CDTHRCTL doesn't exist prior to 240A (in fact that register offset is
 	 * in the FIFO region, so we really shouldn't access it).
 	 */
-	if (host->verid < DW_MMC_240A)
+	if (host->verid < DW_MMC_240A ||
+		(host->verid < DW_MMC_280A && data->flags & MMC_DATA_WRITE))
 		return;
 
+	/*
+	 * Card write Threshold is introduced since 2.80a
+	 * It's used when HS400 mode is enabled.
+	 */
+	if (data->flags & MMC_DATA_WRITE &&
+		!(host->timing != MMC_TIMING_MMC_HS400))
+		return;
+
+	if (data->flags & MMC_DATA_WRITE)
+		enable = SDMMC_CARD_WR_THR_EN;
+	else
+		enable = SDMMC_CARD_RD_THR_EN;
+
 	if (host->timing != MMC_TIMING_MMC_HS200 &&
-	    host->timing != MMC_TIMING_MMC_HS400 &&
 	    host->timing != MMC_TIMING_UHS_SDR104)
 		goto disable;
 
@@ -931,11 +943,11 @@ static void dw_mci_ctrl_rd_thld(struct dw_mci *host, struct mmc_data *data)
 	 * Currently just choose blksz.
 	 */
 	thld_size = blksz;
-	mci_writel(host, CDTHRCTL, SDMMC_SET_RD_THLD(thld_size, 1));
+	mci_writel(host, CDTHRCTL, SDMMC_SET_THLD(thld_size, enable));
 	return;
 
 disable:
-	mci_writel(host, CDTHRCTL, SDMMC_SET_RD_THLD(0, 0));
+	mci_writel(host, CDTHRCTL, 0);
 }
 
 static int dw_mci_submit_data_dma(struct dw_mci *host, struct mmc_data *data)
@@ -1006,12 +1018,12 @@ static void dw_mci_submit_data(struct dw_mci *host, struct mmc_data *data)
 	host->sg = NULL;
 	host->data = data;
 
-	if (data->flags & MMC_DATA_READ) {
+	if (data->flags & MMC_DATA_READ)
 		host->dir_status = DW_MCI_RECV_STATUS;
-		dw_mci_ctrl_rd_thld(host, data);
-	} else {
+	else
 		host->dir_status = DW_MCI_SEND_STATUS;
-	}
+
+	dw_mci_ctrl_thld(host, data);
 
 	if (dw_mci_submit_data_dma(host, data)) {
 		if (host->data->flags & MMC_DATA_READ)

drivers/mmc/host/dw_mmc.h

@@ -15,6 +15,7 @@
 #define _DW_MMC_H_
 
 #define DW_MMC_240A		0x240a
+#define DW_MMC_280A		0x280a
 
 #define SDMMC_CTRL		0x000
 #define SDMMC_PWREN		0x004
@@ -175,7 +176,10 @@
 /* Version ID register define */
 #define SDMMC_GET_VERID(x)		((x) & 0xFFFF)
 /* Card read threshold */
-#define SDMMC_SET_RD_THLD(v, x)		(((v) & 0xFFF) << 16 | (x))
+#define SDMMC_SET_THLD(v, x)		(((v) & 0xFFF) << 16 | (x))
+#define SDMMC_CARD_WR_THR_EN		BIT(2)
+#define SDMMC_CARD_RD_THR_EN		BIT(0)
+/* UHS-1 register defines */
 #define SDMMC_UHS_18V			BIT(0)
 /* All ctrl reset bits */
 #define SDMMC_CTRL_ALL_RESET_FLAGS \