ARC: [plat-hsdk] Increase SDIO CIU frequency to 50000000Hz

[linux-2.6-microblaze.git] / arch / arc / plat-hsdk / platform.c

diff --git a/arch/arc/plat-hsdk/platform.c b/arch/arc/plat-hsdk/platform.c
index 744e62e..fd0ae5e 100644 (file)
--- a/arch/arc/plat-hsdk/platform.c
+++ b/arch/arc/plat-hsdk/platform.c
@@ -74,6 +74,10 @@ static void __init hsdk_set_cpu_freq_1ghz(void)
                pr_err("Failed to setup CPU frequency to 1GHz!");
 }
 
+#define SDIO_BASE              (ARC_PERIPHERAL_BASE + 0xA000)
+#define SDIO_UHS_REG_EXT       (SDIO_BASE + 0x108)
+#define SDIO_UHS_REG_EXT_DIV_2 (2 << 30)
+
 static void __init hsdk_init_early(void)
 {
        /*
@@ -89,6 +93,12 @@ static void __init hsdk_init_early(void)
        /* Really apply settings made above */
        writel(1, (void __iomem *) CREG_PAE_UPDATE);
 
+       /*
+        * Switch SDIO external ciu clock divider from default div-by-8 to
+        * minimum possible div-by-2.
+        */
+       iowrite32(SDIO_UHS_REG_EXT_DIV_2, (void __iomem *) SDIO_UHS_REG_EXT);
+
        /*
         * Setup CPU frequency to 1GHz.
         * TODO: remove it after smart hsdk pll driver will be introduced.