Hello William, > On 2023/3/29 0:08, Shengyu Qu wrote: >> Hello William, >> >> Sorry for making noise about this, but seems deleted voltage swtich function >> >> doesn't help about this. But there's still a problem about eMMC speed. Currently >> >> only about 20MB/s maximum reading speed could be reached when using eMMC >> >> on VF2, any idea about this? >> >> Best regards, >> >> Shengyu >> >> 在 2023/3/28 0:01, Shengyu Qu 写道: >>> Hello William, >>> >>> I'm digging into downstream mmc driver these days and found a problem >>> >>> that current version mainline driver doesn't has a voltage switch function for >>> >>> it. Downstream older version has one but was deleted in this commit [1]. >>> >>> It was deleted since vf2's SD slot doesn't have 1.8V input but commiter forgot >>> >>> that vf2's eMMC slot has a proper 1.8V input. >>> >>> So could you add voltage switch function for mainline? I've met a eMMC speed >>> >>> problem possibly due to it. >>> >>> Best regards, >>> >>> Shengyu >>> > > Hi Shengyu, > > Sorry for the late reply. > > First of all, I will consider adding voltage switch function, but the implementation > method is to configure the pmic register configuration in dts, and the implementation > interface will use the voltage switch function in dw_mmc.c. > > As for speed, the main reason for the low rate is the clock of JH7110 and the > associated IO driving strength, in this limit, the maximum reading speed I tested was > about 50Mb/s. > > I will try to reproduce your problem and try to solve it. Thanks for suggestions. > > Best regards, > William I found out the reason and fixed that. dmwci driver needs vqmmc supply configured in device tree and a successful voltage change to actually enable 1.8v mode, even 1.8 supply actually already physically exists. So to solve this problem, I wrote AXP15060 driver and device tree bindings basing on -upstream branch and gets over 75MB/s read speed. The driver series is already under review here: https://lore.kernel.org/all/TY3P286MB26117891DFB2DD615A7C54EF98969@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/ Best regards, Shengyu
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