mmc: SDHC 3.0: support 10-bit divided clock mode

Signed-off-by: Zhangfei Gao <zgao6@marvell.com>
Cc: Michał Mirosław <mirqus@gmail.com>
Cc: David Vrabel <david.vrabel@csr.com>
Reviewed-by: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Chris Ball <cjb@laptop.org>

2 files changed, 25 insertions, 5 deletions

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index e0536175185a..4432fec7467a 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1001,13 +1001,28 @@ static void sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
         if (clock == 0)
                 goto out;
 
-        for (div = 1;div < 256;div *= 2) {
-                if ((host->max_clk / div) <= clock)
-                        break;
+        if (host->version >= SDHCI_SPEC_300) {
+                /* Version 3.00 divisors must be a multiple of 2. */
+                if (host->max_clk <= clock)
+                        div = 1;
+                else {
+                        for (div = 2; div < 2046; div += 2) {
+                                if ((host->max_clk / div) <= clock)
+                                        break;
+                        }
+                }
+        } else {
+                /* Version 2.00 divisors must be a power of 2. */
+                for (div = 1; div < 256; div *= 2) {
+                        if ((host->max_clk / div) <= clock)
+                                break;
+                }
         }
         div >>= 1;
 
-        clk = div << SDHCI_DIVIDER_SHIFT;
+        clk = (div & SDHCI_DIV_MASK) << SDHCI_DIVIDER_SHIFT;
+        clk |= ((div & SDHCI_DIV_HI_MASK) >> SDHCI_DIV_MASK_LEN)
+                << SDHCI_DIVIDER_HI_SHIFT;
         clk |= SDHCI_CLOCK_INT_EN;
         sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
 
@@ -1708,7 +1723,7 @@ int sdhci_add_host(struct sdhci_host *host)
         host->version = sdhci_readw(host, SDHCI_HOST_VERSION);
         host->version = (host->version & SDHCI_SPEC_VER_MASK)
                                 >> SDHCI_SPEC_VER_SHIFT;
-        if (host->version > SDHCI_SPEC_200) {
+        if (host->version > SDHCI_SPEC_300) {
                 printk(KERN_ERR "%s: Unknown controller version (%d). "
                         "You may experience problems.\n", mmc_hostname(mmc),
                         host->version);
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index d316bc79b636..950d4fd90072 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -86,6 +86,10 @@
 
 #define SDHCI_CLOCK_CONTROL     0x2C
 #define  SDHCI_DIVIDER_SHIFT    8
+#define  SDHCI_DIVIDER_HI_SHIFT 6
+#define  SDHCI_DIV_MASK 0xFF
+#define  SDHCI_DIV_MASK_LEN     8
+#define  SDHCI_DIV_HI_MASK      0x300
 #define  SDHCI_CLOCK_CARD_EN    0x0004
 #define  SDHCI_CLOCK_INT_STABLE 0x0002
 #define  SDHCI_CLOCK_INT_EN     0x0001
@@ -178,6 +182,7 @@
 #define  SDHCI_SPEC_VER_SHIFT   0
 #define   SDHCI_SPEC_100        0
 #define   SDHCI_SPEC_200        1
+#define   SDHCI_SPEC_300        2
 
 struct sdhci_ops;