ufs: Add glue layer driver for TI J721E devices

Add glue layer driver for the controller present on TI's J721E devices.

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>

drivers/ufs/Kconfig

@@ -14,4 +14,10 @@ config CADENCE_UFS
 	  This selects the platform driver for the Cadence UFS host
 	  controller present on present TI's J721e devices.
 
+config TI_J721E_UFS
+	bool "Glue Layer driver for UFS on TI J721E devices"
+	help
+	  This selects the glue layer driver for Cadence controller
+	  present on TI's J721E devices.
+
 endmenu

drivers/ufs/Makefile

@@ -5,3 +5,4 @@
 
 obj-$(CONFIG_UFS) += ufs.o ufs-uclass.o
 obj-$(CONFIG_CADENCE_UFS) += cdns-platform.o
+obj-$(CONFIG_TI_J721E_UFS) += ti-j721e-ufs.o

drivers/ufs/ti-j721e-ufs.c

@@ -0,0 +1,71 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019 Texas Instruments Incorporated - http://www.ti.com/
+ */
+
+#include <asm/io.h>
+#include <clk.h>
+#include <common.h>
+#include <dm.h>
+
+#define UFS_SS_CTRL             0x4
+#define UFS_SS_RST_N_PCS        BIT(0)
+#define UFS_SS_CLK_26MHZ        BIT(4)
+
+static int ti_j721e_ufs_probe(struct udevice *dev)
+{
+	void __iomem *base;
+	unsigned int clock;
+	struct clk clk;
+	u32 reg = 0;
+	int ret;
+
+	ret = clk_get_by_index(dev, 0, &clk);
+	if (ret) {
+		dev_err(dev, "failed to get M-PHY clock\n");
+		return ret;
+	}
+
+	clock = clk_get_rate(&clk);
+	if (IS_ERR_VALUE(clock)) {
+		dev_err(dev, "failed to get rate\n");
+		return ret;
+	}
+
+	base = dev_remap_addr_index(dev, 0);
+
+	if (clock == 26000000)
+		reg |= UFS_SS_CLK_26MHZ;
+	/* Take UFS slave device out of reset */
+	reg |= UFS_SS_RST_N_PCS;
+	writel(reg, base + UFS_SS_CTRL);
+
+	return 0;
+}
+
+static int ti_j721e_ufs_remove(struct udevice *dev)
+{
+	void __iomem *base = dev_remap_addr_index(dev, 0);
+	u32 reg = readl(base + UFS_SS_CTRL);
+
+	reg &= ~UFS_SS_RST_N_PCS;
+	writel(reg, base + UFS_SS_CTRL);
+
+	return 0;
+}
+
+static const struct udevice_id ti_j721e_ufs_ids[] = {
+	{
+		.compatible = "ti,j721e-ufs",
+	},
+	{},
+};
+
+U_BOOT_DRIVER(ti_j721e_ufs) = {
+	.name			= "ti-j721e-ufs",
+	.id			= UCLASS_MISC,
+	.of_match		= ti_j721e_ufs_ids,
+	.probe			= ti_j721e_ufs_probe,
+	.remove			= ti_j721e_ufs_remove,
+	.flags			= DM_FLAG_OS_PREPARE,
+};