[PATCH 2/4] sdhci-of: Avoid writing reserved bits into host control register

[Anton Vorontsov <avorontsov@ru.mvista.com>]

SDHCI core tries to write HISPD bit into the host control register,
but the eSDHC controllers don't have that bit, and that causes
all sorts of misbehaviour when using 4-bit mode capable SD cards.

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
---
 drivers/mmc/host/sdhci-of.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of.c b/drivers/mmc/host/sdhci-of.c
index 92b5667..8440fd9 100644
--- a/drivers/mmc/host/sdhci-of.c
+++ b/drivers/mmc/host/sdhci-of.c
@@ -48,6 +48,8 @@ struct sdhci_of_host {
 #define ESDHC_CLOCK_HCKEN	0x00000002
 #define ESDHC_CLOCK_IPGEN	0x00000001
 
+#define ESDHC_HOST_CONTROL_RES	0x05
+
 static u32 esdhc_readl(struct sdhci_host *host, int reg)
 {
 	return in_be32(host->ioaddr + reg);
@@ -109,6 +111,10 @@ static void esdhc_writeb(struct sdhci_host *host, u8 val, int reg)
 	int base = reg & ~0x3;
 	int shift = (reg & 0x3) * 8;
 
+	/* Prevent SDHCI core from writing reserved bits (e.g. HISPD). */
+	if (reg == SDHCI_HOST_CONTROL)
+		val &= ~ESDHC_HOST_CONTROL_RES;
+
 	clrsetbits_be32(host->ioaddr + base , 0xff << shift, val << shift);
 }
 
-- 
1.6.3.3