> > 1. The SDHI/MMC clocks now run much slower than before. Perhaps this is > > intentional, and a consequence of finding the best way to drive the SD > > card at the target frequency? > > I don't think is generally a problem. Probably even saves a little > power.
If you insert an SD card, frequencies should be back to normal. This happens on Lager at least. > > > 2. On r8a7740, the situation is worse: the HP ("High-speed Peripheral") > > clock is also scaled down from 99 MHz to 12.375 MHz. > > As the HP clock is the parent of lots of on-chip devices, this may > > affect > > performance for all of them. > > > > On r8a73a4, r8a7791, and sh73a0, the SDHI clocks are children of the > > pll1_div2 > > clocks, which are fixed. > > On r8a7740, the SDHI and MMC clocks are children of the HP clock, > > which is also scaled down, affecting all other siblings. > [...] > > That seems like a bug in the clock driver. If it doesn't have > independent dividers for each clock client then it shouldn't allow any > client to change the frequency. I tend to agree. However, I just found out that we don't check the result of clk_set_rate(). Probably something like this is missing? diff --git a/drivers/mmc/host/sh_mobile_sdhi.c b/drivers/mmc/host/sh_mobile_sdhi.c index 5923ce7e0fccb3..e51d7b01d39a3b 100644 --- a/drivers/mmc/host/sh_mobile_sdhi.c +++ b/drivers/mmc/host/sh_mobile_sdhi.c @@ -167,7 +167,7 @@ static unsigned int sh_mobile_sdhi_clk_update(struct tmio_mmc_host *host, { struct sh_mobile_sdhi *priv = host_to_priv(host); unsigned int freq, best_freq, diff_min, diff; - int i; + int i, ret; diff_min = ~0; best_freq = 0; @@ -195,9 +195,9 @@ static unsigned int sh_mobile_sdhi_clk_update(struct tmio_mmc_host *host, } } - clk_set_rate(priv->clk, best_freq); + ret = clk_set_rate(priv->clk, best_freq); - return best_freq; + return ret == 0 ? best_freq : clk_get_rate(priv->clk); } static void sh_mobile_sdhi_clk_disable(struct tmio_mmc_host *host)
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