From bbca4ddb9a766f98372bd3db496b84f3aca598a0 Mon Sep 17 00:00:00 2001
From: Yangbo Lu <yangbo.lu@nxp.com>
Date: Tue, 20 Oct 2020 16:11:16 +0800
Subject: [PATCH] mmc: sdhci-of-esdhc: make sure delay chain locked for HS400

commit 011fde48394b7dc8dfd6660d1013b26a00157b80 upstream.

For eMMC HS400 mode initialization, the DLL reset is a required step
if DLL is enabled to use previously, like in bootloader.
This step has not been documented in reference manual, but the RM will
be fixed sooner or later.

This patch is to add the step of DLL reset, and make sure delay chain
locked for HS400.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20201020081116.20918-1-yangbo.lu@nxp.com
Fixes: 54e08d9a95ca ("mmc: sdhci-of-esdhc: add hs400 mode support")
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/mmc/host/sdhci-esdhc.h    |  2 ++
 drivers/mmc/host/sdhci-of-esdhc.c | 17 +++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/drivers/mmc/host/sdhci-esdhc.h b/drivers/mmc/host/sdhci-esdhc.h
index a30796e79b1cb..6de02f09c3222 100644
--- a/drivers/mmc/host/sdhci-esdhc.h
+++ b/drivers/mmc/host/sdhci-esdhc.h
@@ -5,6 +5,7 @@
  * Copyright (c) 2007 Freescale Semiconductor, Inc.
  * Copyright (c) 2009 MontaVista Software, Inc.
  * Copyright (c) 2010 Pengutronix e.K.
+ * Copyright 2020 NXP
  *   Author: Wolfram Sang <kernel@pengutronix.de>
  */
 
@@ -88,6 +89,7 @@
 /* DLL Config 0 Register */
 #define ESDHC_DLLCFG0			0x160
 #define ESDHC_DLL_ENABLE		0x80000000
+#define ESDHC_DLL_RESET			0x40000000
 #define ESDHC_DLL_FREQ_SEL		0x08000000
 
 /* DLL Config 1 Register */
diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
index 45881b3099567..d16fb0b26a789 100644
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -4,6 +4,7 @@
  *
  * Copyright (c) 2007, 2010, 2012 Freescale Semiconductor, Inc.
  * Copyright (c) 2009 MontaVista Software, Inc.
+ * Copyright 2020 NXP
  *
  * Authors: Xiaobo Xie <X.Xie@freescale.com>
  *	    Anton Vorontsov <avorontsov@ru.mvista.com>
@@ -19,6 +20,7 @@
 #include <linux/clk.h>
 #include <linux/ktime.h>
 #include <linux/dma-mapping.h>
+#include <linux/iopoll.h>
 #include <linux/mmc/host.h>
 #include <linux/mmc/mmc.h>
 #include "sdhci-pltfm.h"
@@ -743,6 +745,21 @@ static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int clock)
 		if (host->mmc->actual_clock == MMC_HS200_MAX_DTR)
 			temp |= ESDHC_DLL_FREQ_SEL;
 		sdhci_writel(host, temp, ESDHC_DLLCFG0);
+
+		temp |= ESDHC_DLL_RESET;
+		sdhci_writel(host, temp, ESDHC_DLLCFG0);
+		udelay(1);
+		temp &= ~ESDHC_DLL_RESET;
+		sdhci_writel(host, temp, ESDHC_DLLCFG0);
+
+		/* Wait max 20 ms */
+		if (read_poll_timeout(sdhci_readl, temp,
+				      temp & ESDHC_DLL_STS_SLV_LOCK,
+				      10, 20000, false,
+				      host, ESDHC_DLLSTAT0))
+			pr_err("%s: timeout for delay chain lock.\n",
+			       mmc_hostname(host->mmc));
+
 		temp = sdhci_readl(host, ESDHC_TBCTL);
 		sdhci_writel(host, temp | ESDHC_HS400_WNDW_ADJUST, ESDHC_TBCTL);