• Kyoungil Kim's avatar
    mmc: sdio: Use multiple scatter/gather list · 968a64ea
    Kyoungil Kim authored
    Before this patch, we always used only single sg entry for SDIO transfer.
    This patch switches to using multiple sg entries. In the case of dwmci,
    it supports only up to 4KB size per single sg entry. So if we want to
    transfer more than 4KB, we should send more than 1 command.
    
    When we tested before applying this patch, it took around 335 us for
    5K(5120) bytes transfer with dwmci controller. After applying this patch,
    it takes 242 us for 5K bytes. So this patch makes around 38% performance
    improvement for 5K bytes transfer. If the transfer size is bigger, then
    the performance improvement ratio will be increased.
    Signed-off-by: default avatarKyoungil Kim <ki0351.kim@samsung.com>
    Signed-off-by: default avatarChris Ball <cjb@laptop.org>
    968a64ea
sdio_ops.c 4.85 KB