From ed880b7572e1135e3bd8382d4670a375f7d9c91b Mon Sep 17 00:00:00 2001 From: Weijie Gao Date: Tue, 2 Mar 2021 15:56:17 +0800 Subject: [PATCH 10/21] mmc: mtk-sd: increase the minimum bus frequency With a 48MHz input clock, the lowest bus frequency can be as low as 48000000 / (4 * 4095) = 2930Hz. Such an extremely low frequency will cause the mmc framework take seconds to finish the initialization. Limiting the minimum bus frequency to a slightly higher value can solve the issue without any side effects. Signed-off-by: Weijie Gao --- drivers/mmc/mtk-sd.c | 5 +++++ 1 file changed, 5 insertions(+) --- a/drivers/mmc/mtk-sd.c +++ b/drivers/mmc/mtk-sd.c @@ -232,6 +232,8 @@ #define SCLK_CYCLES_SHIFT 20 +#define MIN_BUS_CLK 260000 + #define CMD_INTS_MASK \ (MSDC_INT_CMDRDY | MSDC_INT_RSPCRCERR | MSDC_INT_CMDTMO) @@ -1639,6 +1641,9 @@ static int msdc_drv_probe(struct udevice else cfg->f_min = host->src_clk_freq / (4 * 4095); + if (cfg->f_min < MIN_BUS_CLK) + cfg->f_min = MIN_BUS_CLK; + if (cfg->f_max < cfg->f_min || cfg->f_max > host->src_clk_freq) cfg->f_max = host->src_clk_freq;