mmc: sdhci-of-dwcmshc: add reset call back for rockchip Socs

The reset function build in the SDHCI will not reset the logic
circuit related to the tuning function, which may cause data
reading errors. Resetting the complete SDHCI controller through
the reset controller fixes the issue.

Signed-off-by: Yifeng Zhao <yifeng.zhao@rock-chips.com>
[rebase, use optional variant of reset getter]
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://lore.kernel.org/r/20220504213251.264819-10-sebastian.reichel@collabora.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/sdhci-of-dwcmshc.c

@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/reset.h>
 #include <linux/sizes.h>
 
 #include "sdhci-pltfm.h"
@@ -63,6 +64,7 @@
 struct rk3568_priv {
 	/* Rockchip specified optional clocks */
 	struct clk_bulk_data rockchip_clks[RK3568_MAX_CLKS];
+	struct reset_control *reset;
 	u8 txclk_tapnum;
 };
 
@@ -255,6 +257,21 @@ static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock
 	sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_STRBIN);
 }
 
+static void rk35xx_sdhci_reset(struct sdhci_host *host, u8 mask)
+{
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct dwcmshc_priv *dwc_priv = sdhci_pltfm_priv(pltfm_host);
+	struct rk35xx_priv *priv = dwc_priv->priv;
+
+	if (mask & SDHCI_RESET_ALL && priv->reset) {
+		reset_control_assert(priv->reset);
+		udelay(1);
+		reset_control_deassert(priv->reset);
+	}
+
+	sdhci_reset(host, mask);
+}
+
 static const struct sdhci_ops sdhci_dwcmshc_ops = {
 	.set_clock		= sdhci_set_clock,
 	.set_bus_width		= sdhci_set_bus_width,
@@ -269,7 +286,7 @@ static const struct sdhci_ops sdhci_dwcmshc_rk3568_ops = {
 	.set_bus_width		= sdhci_set_bus_width,
 	.set_uhs_signaling	= dwcmshc_set_uhs_signaling,
 	.get_max_clock		= sdhci_pltfm_clk_get_max_clock,
-	.reset			= sdhci_reset,
+	.reset			= rk35xx_sdhci_reset,
 	.adma_write_desc	= dwcmshc_adma_write_desc,
 };
 
@@ -292,6 +309,13 @@ static int dwcmshc_rk3568_init(struct sdhci_host *host, struct dwcmshc_priv *dwc
 	int err;
 	struct rk3568_priv *priv = dwc_priv->priv;
 
+	priv->reset = devm_reset_control_array_get_optional_exclusive(mmc_dev(host->mmc));
+	if (IS_ERR(priv->reset)) {
+		err = PTR_ERR(priv->reset);
+		dev_err(mmc_dev(host->mmc), "failed to get reset control %d\n", err);
+		return err;
+	}
+
 	priv->rockchip_clks[0].id = "axi";
 	priv->rockchip_clks[1].id = "block";
 	priv->rockchip_clks[2].id = "timer";