From 285edfd7821e79de579b0bf1a7328dead2304a0b Mon Sep 17 00:00:00 2001 From: Michael Walle Date: Fri, 10 Sep 2021 11:20:52 +0200 Subject: [PATCH] mmc: fsl_esdhc: remove 1ms sleep in esdhc_send_cmd_common() 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 9098682200e6 ("mmc: fsl_esdhc_imx: remove the 1ms delay before sending command"). Signed-off-by: Michael Walle --- drivers/mmc/fsl_esdhc.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c index 1d98fa6..ebb307e 100644 --- a/drivers/mmc/fsl_esdhc.c +++ b/drivers/mmc/fsl_esdhc.c @@ -361,13 +361,6 @@ static int esdhc_send_cmd_common(struct fsl_esdhc_priv *priv, struct mmc *mmc, while (esdhc_read32(®s->prsstat) & PRSSTAT_DLA) ; - /* Wait at least 8 SD clock cycles before the next command */ - /* - * Note: This is way more than 8 cycles, but 1ms seems to - * resolve timing issues with some cards - */ - udelay(1000); - /* Set up for a data transfer if we have one */ if (data) { err = esdhc_setup_data(priv, mmc, data); -- 2.7.4