sdhci-of: avoid writing reserved bits into host control register
authorAnton Vorontsov <avorontsov@ru.mvista.com>
Tue, 22 Sep 2009 23:45:11 +0000 (16:45 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 23 Sep 2009 14:39:36 +0000 (07:39 -0700)
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>
Cc: Pierre Ossman <pierre@ossman.eu>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: David Vrabel <david.vrabel@csr.com>
Cc: Ben Dooks <ben@fluff.org>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: <linux-mmc@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/mmc/host/sdhci-of.c

index 2b0756934f49e119553437c77ab9d71bd97eecd3..3439fc1189042d1f4a4ee23d8cf2f72fb551fd67 100644 (file)
@@ -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);
 }