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From: haibo.chen at nxp.com <haibo.chen@nxp.com>
To: u-boot@lists.denx.de
Subject: [PATCH 2/2] mmc: fsl_esdhc_imx: remove the 1ms delay before sending command
Date: Tue, 22 Sep 2020 18:11:43 +0800	[thread overview]
Message-ID: <1600769503-30395-2-git-send-email-haibo.chen@nxp.com> (raw)
In-Reply-To: <1600769503-30395-1-git-send-email-haibo.chen@nxp.com>

From: Haibo Chen <haibo.chen@nxp.com>

This 1ms delay before sending command already exist from the beginning
of the fsl_esdhc driver added in year 2008. Now this driver has been
split for two files: fsl_esdhc.c and fsl_esdhc_imx.c. fsl_esdhc_imx.c
only for i.MX series. i.MX series esdhc/usdhc do not need this 1ms delay
before sending any command. So remove this 1ms, this will save a lot
time if handling a large mmc data.

Signed-off-by: Haibo Chen <haibo.chen@nxp.com>
---
 drivers/mmc/fsl_esdhc_imx.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/mmc/fsl_esdhc_imx.c b/drivers/mmc/fsl_esdhc_imx.c
index a0a0903ae4..ac65ed1ee1 100644
--- a/drivers/mmc/fsl_esdhc_imx.c
+++ b/drivers/mmc/fsl_esdhc_imx.c
@@ -462,13 +462,6 @@ static int esdhc_send_cmd_common(struct fsl_esdhc_priv *priv, struct mmc *mmc,
 	while (esdhc_read32(&regs->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);
-- 
2.17.1

      reply	other threads:[~2020-09-22 10:11 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-22 10:11 [PATCH 1/2] mmc: do not send cmd13 if the parameter 'send_status' is 0 for __mmc_switch haibo.chen at nxp.com
2020-09-22 10:11 ` haibo.chen at nxp.com [this message]

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