From 4e782b594089cc3946314325faebad8c318565f4 Mon Sep 17 00:00:00 2001 From: Eugeniy Paltsev Date: Sat, 21 Oct 2017 15:35:12 +0300 Subject: ARC: HSDK: Fixup DW SDIO CIU frequency to 50000000Hz DW SDIO controller has external CIU clock divider controlled via register in the SDIO IP. Due to its unexpected default value (we expected it to divide by 1 but in reality it divides by 8) SDIO IP uses wrong CIU clock (it should be 100000000Hz but actual is 12500000Hz) and works unstable (see STAR 9001204800). So increase SDIO CIU frequency from actual 12500000Hz to 50000000Hz by switching from the default divisor value (div-by-8) to the minimum possible value of the divisor (div-by-2) in HSDK platform code. Signed-off-by: Eugeniy Paltsev Signed-off-by: Alexey Brodkin --- board/synopsys/hsdk/hsdk.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) (limited to 'board') diff --git a/board/synopsys/hsdk/hsdk.c b/board/synopsys/hsdk/hsdk.c index 7b562556e6..7641978a7b 100644 --- a/board/synopsys/hsdk/hsdk.c +++ b/board/synopsys/hsdk/hsdk.c @@ -26,6 +26,10 @@ int board_early_init_f(void) return 0; } +#define SDIO_BASE (ARC_PERIPHERAL_BASE + 0xA000) +#define SDIO_UHS_REG_EXT (SDIO_BASE + 0x108) +#define SDIO_UHS_REG_EXT_DIV_2 (2 << 30) + int board_mmc_init(bd_t *bis) { struct dwmci_host *host = NULL; @@ -36,12 +40,18 @@ int board_mmc_init(bd_t *bis) return 1; } + /* + * Switch SDIO external ciu clock divider from default div-by-8 to + * minimum possible div-by-2. + */ + writel(SDIO_UHS_REG_EXT_DIV_2, (void __iomem *) SDIO_UHS_REG_EXT); + memset(host, 0, sizeof(struct dwmci_host)); host->name = "Synopsys Mobile storage"; host->ioaddr = (void *)ARC_DWMMC_BASE; host->buswidth = 4; host->dev_index = 0; - host->bus_hz = 100000000; + host->bus_hz = 50000000; add_dwmci(host, host->bus_hz / 2, 400000); -- cgit v1.2.3