From: Yangbo Lu <yangbo.lu@nxp.com>
Date: Fri, 22 May 2020 11:12:56 +0800
Subject: mmc: sdhci-of-esdhc: exit HS400 properly before setting any speed
 mode

Git-commit: 47e9e107fa31fcdd9eb82b22b7b0ab3c987eb576
Patch-mainline: v5.8-rc1
References: jsc#SLE-12251

The eSDHC HS400 timing requires many specific registers setting,
unlike other speed modes which need to set only host controller 2
register. When driver needs to downgrade HS400 mode to other speed
mode, the controller have to exit HS400 timing properly first.
This patch is to support the procedure of HS400 exiting at the
beginning of esdhc_set_uhs_signaling.

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20200522031256.856-1-yangbo.lu@nxp.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/mmc/host/sdhci-of-esdhc.c | 34 +++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
index 5d8dd870bd44..7c73d243dc6c 100644
--- a/drivers/mmc/host/sdhci-of-esdhc.c
+++ b/drivers/mmc/host/sdhci-of-esdhc.c
@@ -1135,6 +1135,40 @@ static int esdhc_execute_tuning(struct mmc_host *mmc, u32 opcode)
 static void esdhc_set_uhs_signaling(struct sdhci_host *host,
 				   unsigned int timing)
 {
+	u32 val;
+
+	/*
+	 * There are specific registers setting for HS400 mode.
+	 * Clean all of them if controller is in HS400 mode to
+	 * exit HS400 mode before re-setting any speed mode.
+	 */
+	val = sdhci_readl(host, ESDHC_TBCTL);
+	if (val & ESDHC_HS400_MODE) {
+		val = sdhci_readl(host, ESDHC_SDTIMNGCTL);
+		val &= ~ESDHC_FLW_CTL_BG;
+		sdhci_writel(host, val, ESDHC_SDTIMNGCTL);
+
+		val = sdhci_readl(host, ESDHC_SDCLKCTL);
+		val &= ~ESDHC_CMD_CLK_CTL;
+		sdhci_writel(host, val, ESDHC_SDCLKCTL);
+
+		esdhc_clock_enable(host, false);
+		val = sdhci_readl(host, ESDHC_TBCTL);
+		val &= ~ESDHC_HS400_MODE;
+		sdhci_writel(host, val, ESDHC_TBCTL);
+		esdhc_clock_enable(host, true);
+
+		val = sdhci_readl(host, ESDHC_DLLCFG0);
+		val &= ~(ESDHC_DLL_ENABLE | ESDHC_DLL_FREQ_SEL);
+		sdhci_writel(host, val, ESDHC_DLLCFG0);
+
+		val = sdhci_readl(host, ESDHC_TBCTL);
+		val &= ~ESDHC_HS400_WNDW_ADJUST;
+		sdhci_writel(host, val, ESDHC_TBCTL);
+
+		esdhc_tuning_block_enable(host, false);
+	}
+
 	if (timing == MMC_TIMING_MMC_HS400)
 		esdhc_tuning_block_enable(host, true);
 	else
-- 
2.26.2