mmc: sdhci-of-esdhc: fixup PRESENT_STATE read

Since commit 87a18a6 ("mmc: mmc: Use ->card_busy() to detect busy
cards in __mmc_switch()") the ESDHC driver is broken:
  mmc0: Card stuck in programming state! __mmc_switch
  mmc0: error -110 whilst initialising MMC card

Since this commit __mmc_switch() uses ->card_busy(), which is
sdhci_card_busy() for the esdhc driver. sdhci_card_busy() uses the
PRESENT_STATE register, specifically the DAT0 signal level bit. But the
ESDHC uses a non-conformant PRESENT_STATE register, thus a read fixup is
required to make the driver work again.

Signed-off-by: Michael Walle <michael@walle.cc>
Fixes: 87a18a6 ("mmc: mmc: Use ->card_busy() to detect busy cards in __mmc_switch()")
Acked-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: <stable@vger.kernel.org> # v4.8+
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

Author: mwalle

drivers/mmc/host/sdhci-of-esdhc.c

@@ -66,6 +66,20 @@ static u32 esdhc_readl_fixup(struct sdhci_host *host,
 			return ret;
 		}
 	}
+	/*
+	 * The DAT[3:0] line signal levels and the CMD line signal level are
+	 * not compatible with standard SDHC register. The line signal levels
+	 * DAT[7:0] are at bits 31:24 and the command line signal level is at
+	 * bit 23. All other bits are the same as in the standard SDHC
+	 * register.
+	 */
+	if (spec_reg == SDHCI_PRESENT_STATE) {
+		ret = value & 0x000fffff;
+		ret |= (value >> 4) & SDHCI_DATA_LVL_MASK;
+		ret |= (value << 1) & SDHCI_CMD_LVL;
+		return ret;
+	}
+
 	ret = value;
 	return ret;
 }

drivers/mmc/host/sdhci.h

@@ -73,6 +73,7 @@
 #define  SDHCI_DATA_LVL_MASK	0x00F00000
 #define   SDHCI_DATA_LVL_SHIFT	20
 #define   SDHCI_DATA_0_LVL_MASK	0x00100000
+#define  SDHCI_CMD_LVL		0x01000000
 
 #define SDHCI_HOST_CONTROL	0x28
 #define  SDHCI_CTRL_LED		0x01