[PATCH 2/5] mmc: dw-mmc: ensure that the card is not busy when changing clock.

[Jaehoon Chung <jh80.chung@samsung.com>]

To avoid glitches in the card clock output,
need to check whether card is busy or not. 

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/mmc/host/dw_mmc.c |   30 ++++++++++++++++++++++++------
 drivers/mmc/host/dw_mmc.h |    1 +
 2 files changed, 25 insertions(+), 6 deletions(-)

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 36f98c0..8bef3c2 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -623,6 +623,27 @@ static void mci_send_cmd(struct dw_mci_slot *slot, u32 cmd, u32 arg)
 		cmd, arg, cmd_status);
 }
 
+static void dw_mci_inform_ciu(struct dw_mci_slot *slot)
+{
+	struct dw_mci *host = slot->host;
+	unsigned long timeout = jiffies + msecs_to_jiffies(500);
+	u32 ctrl, status;
+
+	do {
+		status = mci_readl(host, STATUS);
+		if (!(status & SDMMC_DATA_BUSY))
+			break;
+		ctrl = mci_readl(host, CTRL);
+		ctrl |= SDMMC_CTRL_RESET;
+		mci_writel(host, CTRL, ctrl);
+	} while (time_before(jiffies, timeout));
+
+	if (status & SDMMC_DATA_BUSY)
+		dev_err(&slot->mmc->class_dev,"Card is busy..!\n");
+
+	mci_send_cmd(slot, SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
+}
+
 static void dw_mci_setup_bus(struct dw_mci_slot *slot)
 {
 	struct dw_mci *host = slot->host;
@@ -650,15 +671,13 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
 		mci_writel(host, CLKSRC, 0);
 
 		/* inform CIU */
-		mci_send_cmd(slot,
-			     SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
+		dw_mci_inform_ciu(slot);
 
 		/* set clock to desired speed */
 		mci_writel(host, CLKDIV, div);
 
 		/* inform CIU */
-		mci_send_cmd(slot,
-			     SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
+		dw_mci_inform_ciu(slot);
 
 		/* enable clock; only low power if no SDIO */
 		clk_en_a = SDMMC_CLKEN_ENABLE << slot->id;
@@ -667,8 +686,7 @@ static void dw_mci_setup_bus(struct dw_mci_slot *slot)
 		mci_writel(host, CLKENA, clk_en_a);
 
 		/* inform CIU */
-		mci_send_cmd(slot,
-			     SDMMC_CMD_UPD_CLK | SDMMC_CMD_PRV_DAT_WAIT, 0);
+		dw_mci_inform_ciu(slot);
 
 		host->current_speed = slot->clock;
 	}
diff --git a/drivers/mmc/host/dw_mmc.h b/drivers/mmc/host/dw_mmc.h
index 15c27e1..b6a1a78 100644
--- a/drivers/mmc/host/dw_mmc.h
+++ b/drivers/mmc/host/dw_mmc.h
@@ -127,6 +127,7 @@
 #define SDMMC_CMD_INDX(n)		((n) & 0x1F)
 /* Status register defines */
 #define SDMMC_GET_FCNT(x)		(((x)>>17) & 0x1FFF)
+#define SDMMC_DATA_BUSY			BIT(9)
 /* Internal DMAC interrupt defines */
 #define SDMMC_IDMAC_INT_AI		BIT(9)
 #define SDMMC_IDMAC_INT_NI		BIT(8)
-- 
1.7.4.1