commit 9ac60a402fd078dafa16a68ffe960cc42ad3bf30
author Yangbo Lu <yangbo.lu@nxp.com> Tue Sep 01 16:58:07 2020 +0800
committer Peng Fan <peng.fan@nxp.com> Mon Oct 12 15:47:06 2020 +0800
tree 8a4ab02a778c62d6210f793d5cf44b7a09bec343
parent dd08eea2021824e29195f01fd4df1c484c91d32f

mmc: fsl_esdhc: fix eMMC HS400 stability issue

There was a fix-up for eMMC HS400 stability issue in Linux.

Patch link:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/
commit/?id=58d0bf843b49fa99588ac9f85178bd8dfd651b53

Description:
Currently only LX2160A eSDHC supports eMMC HS400. According to
a large number of tests, eMMC HS400 failed to work at 150MHz,
and for a few boards failed to work at 175MHz. But eMMC HS400
worked fine on 200MHz. We hadn't found the root cause but
setting eSDHC_DLLCFG0[DLL_FREQ_SEL] = 0 using slow delay chain
seemed to resovle this issue. Let's use this as fixup for now.

Introduce the fix-up in u-boot since the issue could be reproduced
in u-boot too.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>

drivers/mmc/fsl_esdhc.c

diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
index ce87416..a6092ad 100644
--- a/drivers/mmc/fsl_esdhc.c
+++ b/drivers/mmc/fsl_esdhc.c
@@ -644,7 +644,10 @@
 		esdhc_setbits32(&regs->sdclkctl, CMD_CLK_CTL);
 		esdhc_clock_control(priv, true);
 
-		esdhc_setbits32(&regs->dllcfg0, DLL_ENABLE | DLL_FREQ_SEL);
+		if (priv->clock == 200000000)
+			esdhc_setbits32(&regs->dllcfg0, DLL_FREQ_SEL);
+
+		esdhc_setbits32(&regs->dllcfg0, DLL_ENABLE);
 		esdhc_setbits32(&regs->tbctl, HS400_WNDW_ADJUST);
 
 		esdhc_clock_control(priv, false);