mmc: dw_mmc-bluefield: Add driver extension

This commit adds extension to the dw_mmc driver for Mellanox BlueField
SoC. It updates the UHS_REG_EXT register to bring up the eMMC card on
this SoC.
Signed-off-by: Liming Sun <lsun@mellanox.com>
Reviewed-by: David Woods <dwoods@mellanox.com>
Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/mmc/host/Kconfig

@@ -686,6 +686,15 @@ config MMC_DW_PLTFM
 
 	  If unsure, say Y.
 
+config MMC_DW_BLUEFIELD
+	tristate "BlueField specific extensions for Synopsys DW Memory Card Interface"
+	depends on MMC_DW
+	select MMC_DW_PLTFM
+	help
+	  This selects support for Mellanox BlueField SoC specific extensions to
+	  the Synopsys DesignWare Memory Card Interface driver. Select this
+	  option for platforms based on Mellanox BlueField SoC's.
+
 config MMC_DW_EXYNOS
 	tristate "Exynos specific extensions for Synopsys DW Memory Card Interface"
 	depends on MMC_DW

drivers/mmc/host/Makefile

@@ -49,6 +49,7 @@ thunderx-mmc-objs := cavium.o cavium-thunderx.o
 obj-$(CONFIG_MMC_CAVIUM_THUNDERX) += thunderx-mmc.o
 obj-$(CONFIG_MMC_DW)		+= dw_mmc.o
 obj-$(CONFIG_MMC_DW_PLTFM)	+= dw_mmc-pltfm.o
+obj-$(CONFIG_MMC_DW_BLUEFIELD)	+= dw_mmc-bluefield.o
 obj-$(CONFIG_MMC_DW_EXYNOS)	+= dw_mmc-exynos.o
 obj-$(CONFIG_MMC_DW_HI3798CV200) += dw_mmc-hi3798cv200.o
 obj-$(CONFIG_MMC_DW_K3)		+= dw_mmc-k3.o

drivers/mmc/host/dw_mmc-bluefield.c

+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018 Mellanox Technologies.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/mmc.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#include "dw_mmc.h"
+#include "dw_mmc-pltfm.h"
+
+#define UHS_REG_EXT_SAMPLE_MASK		GENMASK(22, 16)
+#define UHS_REG_EXT_DRIVE_MASK		GENMASK(29, 23)
+#define BLUEFIELD_UHS_REG_EXT_SAMPLE	2
+#define BLUEFIELD_UHS_REG_EXT_DRIVE	4
+
+static void dw_mci_bluefield_set_ios(struct dw_mci *host, struct mmc_ios *ios)
+{
+	u32 reg;
+
+	/* Update the Drive and Sample fields in register UHS_REG_EXT. */
+	reg = mci_readl(host, UHS_REG_EXT);
+	reg &= ~UHS_REG_EXT_SAMPLE_MASK;
+	reg |= FIELD_PREP(UHS_REG_EXT_SAMPLE_MASK,
+			  BLUEFIELD_UHS_REG_EXT_SAMPLE);
+	reg &= ~UHS_REG_EXT_DRIVE_MASK;
+	reg |= FIELD_PREP(UHS_REG_EXT_DRIVE_MASK, BLUEFIELD_UHS_REG_EXT_DRIVE);
+	mci_writel(host, UHS_REG_EXT, reg);
+}
+
+static const struct dw_mci_drv_data bluefield_drv_data = {
+	.set_ios		= dw_mci_bluefield_set_ios
+};
+
+static const struct of_device_id dw_mci_bluefield_match[] = {
+	{ .compatible = "mellanox,bluefield-dw-mshc",
+	  .data = &bluefield_drv_data },
+	{},
+};
+MODULE_DEVICE_TABLE(of, dw_mci_bluefield_match);
+
+static int dw_mci_bluefield_probe(struct platform_device *pdev)
+{
+	const struct dw_mci_drv_data *drv_data = NULL;
+	const struct of_device_id *match;
+
+	if (pdev->dev.of_node) {
+		match = of_match_node(dw_mci_bluefield_match,
+				      pdev->dev.of_node);
+		drv_data = match->data;
+	}
+
+	return dw_mci_pltfm_register(pdev, drv_data);
+}
+
+static struct platform_driver dw_mci_bluefield_pltfm_driver = {
+	.probe		= dw_mci_bluefield_probe,
+	.remove		= dw_mci_pltfm_remove,
+	.driver		= {
+		.name		= "dwmmc_bluefield",
+		.of_match_table	= dw_mci_bluefield_match,
+		.pm		= &dw_mci_pltfm_pmops,
+	},
+};
+
+module_platform_driver(dw_mci_bluefield_pltfm_driver);
+
+MODULE_DESCRIPTION("BlueField DW Multimedia Card driver");
+MODULE_AUTHOR("Mellanox Technologies");
+MODULE_LICENSE("GPL v2");