diff --git a/arch/arc/boot/dts/hsdk.dts b/arch/arc/boot/dts/hsdk.dts index 8adde1b492f1..8f627c200d60 100644 --- a/arch/arc/boot/dts/hsdk.dts +++ b/arch/arc/boot/dts/hsdk.dts @@ -137,14 +137,15 @@ mmcclk_ciu: mmcclk-ciu { /* * DW sdio controller has external ciu clock divider * controlled via register in SDIO IP. Due to its - * unexpected default value (it should devide by 1 - * but it devides by 8) SDIO IP uses wrong clock and + * unexpected default value (it should divide by 1 + * but it divides by 8) SDIO IP uses wrong clock and * works unstable (see STAR 9001204800) + * We switched to the minimum possible value of the + * divisor (div-by-2) in HSDK platform code. * So add temporary fix and change clock frequency - * from 100000000 to 12500000 Hz until we fix dw sdio - * driver itself. + * to 50000000 Hz until we fix dw sdio driver itself. */ - clock-frequency = <12500000>; + clock-frequency = <50000000>; #clock-cells = <0>; }; diff --git a/arch/arc/plat-hsdk/platform.c b/arch/arc/plat-hsdk/platform.c index 744e62e58788..fd0ae5e38639 100644 --- 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.