Add a specific glue layer for UniPhier SoC platform to support
USB host mode. It manages hardware operating sequences to enable multiple
clock gates and assert resets, and to prepare to use dwc3 controller
on the SoC.

This patch also handles the physical layer that has same register space
as the glue layer, because it needs to integrate initialziation sequence
between glue and phy.

In case of some SoCs, since some initialization values for PHY are
included in nvmem, this patch includes the way to get the values from nvmem.

It supports PXs2 and LD20 SoCs.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Signed-off-by: Motoya Tanigawa <redacted>
Signed-off-by: Masami Hiramatsu <redacted>
---
 drivers/usb/dwc3/Kconfig         |   9 +
 drivers/usb/dwc3/Makefile        |   1 +
 drivers/usb/dwc3/dwc3-uniphier.c | 554 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 564 insertions(+)
 create mode 100644 drivers/usb/dwc3/dwc3-uniphier.c

diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig
index ab8c0e0..a5cadc6 100644
--- a/drivers/usb/dwc3/Kconfig
+++ b/drivers/usb/dwc3/Kconfig

@@ -106,4 +106,13 @@ config USB_DWC3_ST
 	  inside (i.e. STiH407).
 	  Say 'Y' or 'M' if you have one such device.
 
+config USB_DWC3_UNIPHIER
+	tristate "Socionext UniPhier Platforms"
+	depends on (ARCH_UNIPHIER || COMPILE_TEST) && OF
+	default USB_DWC3
+	help
+	  Support USB2/3 functionality in UniPhier platforms.
+	  Say 'Y' or 'M' if your system that UniPhier SoC is implemented
+	  has USB controllers based on DWC USB3 IP.
+
 endif

diff --git a/drivers/usb/dwc3/Makefile b/drivers/usb/dwc3/Makefile
index 7ac7250..31e82b3 100644
--- a/drivers/usb/dwc3/Makefile
+++ b/drivers/usb/dwc3/Makefile

@@ -48,3 +48,4 @@ obj-$(CONFIG_USB_DWC3_PCI)		+= dwc3-pci.o
 obj-$(CONFIG_USB_DWC3_KEYSTONE)		+= dwc3-keystone.o
 obj-$(CONFIG_USB_DWC3_OF_SIMPLE)	+= dwc3-of-simple.o
 obj-$(CONFIG_USB_DWC3_ST)		+= dwc3-st.o
+obj-$(CONFIG_USB_DWC3_UNIPHIER)		+= dwc3-uniphier.o

diff --git a/drivers/usb/dwc3/dwc3-uniphier.c b/drivers/usb/dwc3/dwc3-uniphier.c
new file mode 100644
index 0000000..58e84cd
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3-uniphier.c

@@ -0,0 +1,554 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * dwc3-uniphier.c - Socionext UniPhier DWC3 specific glue layer
+ *
+ * Copyright 2015-2018 Socionext Inc.
+ *
+ * Author:
+ *	Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
+ * Contributors:
+ *      Motoya Tanigawa <tanigawa.motoya@socionext.com>
+ *      Masami Hiramatsu <masami.hiramatsu@linaro.org>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/bitops.h>
+#include <linux/clk.h>
+#include <linux/clk-provider.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/nvmem-consumer.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+
+#define RESET_CTL		0x000
+#define LINK_RESET		BIT(15)
+
+#define VBUS_CONTROL(n)		(0x100 + 0x10 * (n))
+#define DRVVBUS_REG		BIT(4)
+#define DRVVBUS_REG_EN		BIT(3)
+
+#define U2PHY_CFG0(n)		(0x200 + 0x10 * (n))
+#define U2PHY_CFG0_HS_I_MASK	GENMASK(31, 28)
+#define U2PHY_CFG0_HSDISC_MASK	GENMASK(27, 26)
+#define U2PHY_CFG0_SWING_MASK	GENMASK(17, 16)
+#define U2PHY_CFG0_SEL_T_MASK	GENMASK(15, 12)
+#define U2PHY_CFG0_RTERM_MASK	GENMASK(7, 6)
+#define U2PHY_CFG0_TRIMMASK	(U2PHY_CFG0_HS_I_MASK \
+				 | U2PHY_CFG0_SEL_T_MASK \
+				 | U2PHY_CFG0_RTERM_MASK)
+
+#define U2PHY_CFG1(n)		(0x204 + 0x10 * (n))
+#define U2PHY_CFG1_DAT_EN	BIT(29)
+#define U2PHY_CFG1_ADR_EN	BIT(28)
+#define U2PHY_CFG1_ADR_MASK	GENMASK(27, 16)
+#define U2PHY_CFG1_DAT_MASK	GENMASK(23, 16)
+
+#define U3PHY_TESTI(n)		(0x300 + 0x10 * (n))
+#define U3PHY_TESTO(n)		(0x304 + 0x10 * (n))
+#define TESTI_DAT_MASK		GENMASK(13, 6)
+#define TESTI_ADR_MASK		GENMASK(5, 1)
+#define TESTI_WR_EN		BIT(0)
+
+#define HOST_CONFIG0		0x400
+#define NUM_U3_MASK		GENMASK(13, 11)
+#define NUM_U2_MASK		GENMASK(10, 8)
+
+#define PHY_MAX_PARAMS	32
+
+struct dwc3u_phy_param {
+	u32 addr;
+	u32 mask;
+	u32 val;
+};
+
+struct dwc3u_trim_param {
+	u32 rterm;
+	u32 sel_t;
+	u32 hs_i;
+};
+
+#define trim_param_is_valid(p)	((p)->rterm || (p)->sel_t || (p)->hs_i)
+
+struct dwc3u_priv {
+	struct device		*dev;
+	void __iomem		*base;
+	struct clk		**clks;
+	int			nclks;
+	struct reset_control	*rst;
+	int			nvbus;
+	const struct dwc3u_soc_data	*data;
+};
+
+struct dwc3u_soc_data {
+	int ss_nparams;
+	struct dwc3u_phy_param ss_param[PHY_MAX_PARAMS];
+	int hs_nparams;
+	struct dwc3u_phy_param hs_param[PHY_MAX_PARAMS];
+	u32 hs_config0;
+	u32 hs_config1;
+	void (*trim_func)(struct dwc3u_priv *priv, u32 *pconfig,
+			  struct dwc3u_trim_param *trim);
+};
+
+static inline u32 dwc3u_read(struct dwc3u_priv *priv, off_t offset)
+{
+	return readl(priv->base + offset);
+}
+
+static inline void dwc3u_write(struct dwc3u_priv *priv,
+			       off_t offset, u32 val)
+{
+	writel(val, priv->base + offset);
+}
+
+static inline void dwc3u_maskwrite(struct dwc3u_priv *priv,
+				   off_t offset, u32 mask, u32 val)
+{
+	u32 tmp;
+
+	tmp = dwc3u_read(priv, offset);
+	dwc3u_write(priv, offset, (tmp & ~mask) | (val & mask));
+}
+
+static int dwc3u_get_hsport_num(struct dwc3u_priv *priv)
+{
+	return FIELD_GET(NUM_U2_MASK, dwc3u_read(priv, HOST_CONFIG0));
+}
+
+static int dwc3u_get_ssport_num(struct dwc3u_priv *priv)
+{
+	return FIELD_GET(NUM_U3_MASK, dwc3u_read(priv, HOST_CONFIG0));
+}
+
+static int dwc3u_get_nvparam(struct dwc3u_priv *priv,
+			     const char *basename, int index, u8 *dst,
+			     int maxlen)
+{
+	struct nvmem_cell *cell;
+	char name[16];
+	size_t len;
+	u8 *buf;
+
+	snprintf(name, sizeof(name) - 1, "%s%d", basename, index);
+	memset(dst, 0, maxlen);
+
+	cell = nvmem_cell_get(priv->dev, name);
+	if (IS_ERR(cell))
+		return PTR_ERR(cell);
+
+	buf = nvmem_cell_read(cell, &len);
+	nvmem_cell_put(cell);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	len = min_t(u32, len, maxlen);
+	memcpy(dst, buf, len);
+	kfree(buf);
+
+	return 0;
+}
+
+static int dwc3u_get_nvparam_u32(struct dwc3u_priv *priv,
+				 const char *basename, int index, u32 *p_val)
+{
+	return dwc3u_get_nvparam(priv, basename, index, (u8 *)p_val,
+				 sizeof(u32));
+}
+
+static void dwc3u_ssphy_testio_write(struct dwc3u_priv *priv, int port,
+				     u32 data)