[PATCH 1/2] mmc: fsl_esdhc_imx: use VENDORSPEC_FRC_SDCLK_ON to control card clock output

[haibo.chen at nxp.com]

From: Haibo Chen <haibo.chen at nxp.com>

For FSL_USDHC, it do not implement VENDORSPEC_CKEN/PEREN/HCKEN/IPGEN, these
are reserved bits. Instead, use VENDORSPEC_FRC_SDCLK_ON to gate on/off the
card clock output.

After commit b5874b552ffa ("mmc: fsl_esdhc_imx: add wait_dat0() support"),
we meet SD3.0 card can't work at UHS mode, mmc_switch_voltage() fail because
the second mmc_wait_dat0 return -ETIMEDOUT. According to SD spec, during
voltage switch, need to gate off/on the card clock. If not set the FRC_SDCLK_ON,
after CMD11, hardware will gate off the card clock automatically, so card do
not detect the clock off/on behavior, so will draw the data0 line low until
next command.

Fixes: b5874b552ffa ("mmc: fsl_esdhc_imx: add wait_dat0() support")
Tested-by: Tim Harvey <tharvey at gateworks.com>
Signed-off-by: Haibo Chen <haibo.chen at nxp.com>
---
 drivers/mmc/fsl_esdhc_imx.c | 29 +++++++++++++++++++++--------
 include/fsl_esdhc_imx.h     |  2 ++
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/drivers/mmc/fsl_esdhc_imx.c b/drivers/mmc/fsl_esdhc_imx.c
index e0e132698e..af36558b3c 100644
--- a/drivers/mmc/fsl_esdhc_imx.c
+++ b/drivers/mmc/fsl_esdhc_imx.c
@@ -654,7 +654,10 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
 	clk = (pre_div << 8) | (div << 4);
 
 #ifdef CONFIG_FSL_USDHC
-	esdhc_clrbits32(&regs->vendorspec, VENDORSPEC_CKEN);
+	esdhc_clrbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
+	ret = readx_poll_timeout(esdhc_read32, &regs->prsstat, tmp, tmp & PRSSTAT_SDOFF, 100);
+	if (ret)
+		pr_warn("fsl_esdhc_imx: Internal clock never gate off.\n");
 #else
 	esdhc_clrbits32(&regs->sysctl, SYSCTL_CKEN);
 #endif
@@ -666,7 +669,7 @@ static void set_sysctl(struct fsl_esdhc_priv *priv, struct mmc *mmc, uint clock)
 		pr_warn("fsl_esdhc_imx: Internal clock never stabilised.\n");
 
 #ifdef CONFIG_FSL_USDHC
-	esdhc_setbits32(&regs->vendorspec, VENDORSPEC_PEREN | VENDORSPEC_CKEN);
+	esdhc_setbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
 #else
 	esdhc_setbits32(&regs->sysctl, SYSCTL_PEREN | SYSCTL_CKEN);
 #endif
@@ -721,8 +724,14 @@ static void esdhc_set_strobe_dll(struct mmc *mmc)
 	struct fsl_esdhc_priv *priv = dev_get_priv(mmc->dev);
 	struct fsl_esdhc *regs = priv->esdhc_regs;
 	u32 val;
+	u32 tmp;
+	int ret;
 
 	if (priv->clock > ESDHC_STROBE_DLL_CLK_FREQ) {
+		esdhc_clrbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
+		ret = readx_poll_timeout(esdhc_read32, &regs->prsstat, tmp, tmp & PRSSTAT_SDOFF, 100);
+		if (ret)
+			pr_warn("fsl_esdhc_imx: Internal clock never gate off.\n");
 		esdhc_write32(&regs->strobe_dllctrl, ESDHC_STROBE_DLL_CTRL_RESET);
 
 		/*
@@ -740,6 +749,7 @@ static void esdhc_set_strobe_dll(struct mmc *mmc)
 			pr_warn("HS400 strobe DLL status REF not lock!\n");
 		if (!(val & ESDHC_STROBE_DLL_STS_SLV_LOCK))
 			pr_warn("HS400 strobe DLL status SLV not lock!\n");
+		esdhc_setbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
 	}
 }
 
@@ -963,14 +973,18 @@ static int esdhc_set_ios_common(struct fsl_esdhc_priv *priv, struct mmc *mmc)
 #ifdef MMC_SUPPORTS_TUNING
 	if (mmc->clk_disable) {
 #ifdef CONFIG_FSL_USDHC
-		esdhc_clrbits32(&regs->vendorspec, VENDORSPEC_CKEN);
+		u32 tmp;
+
+		esdhc_clrbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
+		ret = readx_poll_timeout(esdhc_read32, &regs->prsstat, tmp, tmp & PRSSTAT_SDOFF, 100);
+		if (ret)
+			pr_warn("fsl_esdhc_imx: Internal clock never gate off.\n");
 #else
 		esdhc_clrbits32(&regs->sysctl, SYSCTL_CKEN);
 #endif
 	} else {
 #ifdef CONFIG_FSL_USDHC
-		esdhc_setbits32(&regs->vendorspec, VENDORSPEC_PEREN |
-				VENDORSPEC_CKEN);
+		esdhc_setbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
 #else
 		esdhc_setbits32(&regs->sysctl, SYSCTL_PEREN | SYSCTL_CKEN);
 #endif
@@ -1046,7 +1060,7 @@ static int esdhc_init_common(struct fsl_esdhc_priv *priv, struct mmc *mmc)
 #ifndef CONFIG_FSL_USDHC
 	esdhc_setbits32(&regs->sysctl, SYSCTL_HCKEN | SYSCTL_IPGEN);
 #else
-	esdhc_setbits32(&regs->vendorspec, VENDORSPEC_HCKEN | VENDORSPEC_IPGEN);
+	esdhc_setbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
 #endif
 
 	/* Set the initial clock speed */
@@ -1184,8 +1198,7 @@ static int fsl_esdhc_init(struct fsl_esdhc_priv *priv,
 	esdhc_write32(&regs->autoc12err, 0);
 	esdhc_write32(&regs->clktunectrlstatus, 0);
 #else
-	esdhc_setbits32(&regs->vendorspec, VENDORSPEC_PEREN |
-			VENDORSPEC_HCKEN | VENDORSPEC_IPGEN | VENDORSPEC_CKEN);
+	esdhc_setbits32(&regs->vendorspec, VENDORSPEC_FRC_SDCLK_ON);
 #endif
 
 	if (priv->vs18_enable)
diff --git a/include/fsl_esdhc_imx.h b/include/fsl_esdhc_imx.h
index 45ed635a77..b092034464 100644
--- a/include/fsl_esdhc_imx.h
+++ b/include/fsl_esdhc_imx.h
@@ -39,6 +39,7 @@
 #define VENDORSPEC_HCKEN	0x00001000
 #define VENDORSPEC_IPGEN	0x00000800
 #define VENDORSPEC_INIT		0x20007809
+#define VENDORSPEC_FRC_SDCLK_ON 0x00000100
 
 #define IRQSTAT			0x0002e030
 #define IRQSTAT_DMAE		(0x10000000)
@@ -96,6 +97,7 @@
 #define PRSSTAT_CINS		(0x00010000)
 #define PRSSTAT_BREN		(0x00000800)
 #define PRSSTAT_BWEN		(0x00000400)
+#define PRSSTAT_SDOFF		(0x00000080)
 #define PRSSTAT_SDSTB		(0X00000008)
 #define PRSSTAT_DLA		(0x00000004)
 #define PRSSTAT_CICHB		(0x00000002)
-- 
2.17.1