• Michael Walle's avatar
    mmc: fsl_esdhc: remove 1ms sleep in esdhc_send_cmd_common() · 285edfd7
    Michael Walle authored and Peng Fan's avatar Peng Fan committed
    Since the beginning of this driver which was initially for the MPC8379
    and MPC8536 SoCs, there is this spurious 1ms delay. According to the
    comment it should actually be only 8 clock cycles. Esp. during EFI block
    transfers, this 1ms add up to a significant delay and slows down EFI
    boot.
    
    I couldn't find any mention in the MPC8536 that there should be a delay
    of 8 clock cycles between commands. The SD card specification mentions that
    the clock has to be left enabled for 8 cycles after a command or
    response. But I don't see how this delay will help with this.
    
    Go ahead and just remove it. If there will ever be any regression we can
    introduce a compile time flag, but for now I'd like to keep it simple.
    
    In the split off imx driver this delay was also removed in commit
    90986822
    
     ("mmc: fsl_esdhc_imx: remove the 1ms delay before sending
    command").
    Signed-off-by: default avatarMichael Walle <michael@walle.cc>
    285edfd7
fsl_esdhc.c 29.5 KB