reset: Add Allwinner RESET driver

Add common reset driver for all Allwinner SoC's.

Since CLK and RESET share common DT compatible, it is CLK driver
job is to bind the reset driver. So add CLK bind call on respective
SoC driver by passing ccu map descriptor so-that reset deassert,
deassert operations held based on ccu reset table defined from
CLK driver.

Select DM_RESET via CLK_SUNXI, this make hidden section of RESET
since CLK and RESET share common DT compatible and code.

Signed-off-by: Jagan Teki <jagan@amarulasolutions.com>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm/include/asm/arch-sunxi/ccu.h

@@ -8,12 +8,14 @@
 #define _ASM_ARCH_CCU_H
 
 /**
- * enum ccu_flags - ccu clock flags
+ * enum ccu_flags - ccu clock/reset flags
  *
  * @CCU_CLK_F_IS_VALID:		is given clock gate is valid?
+ * @CCU_RST_F_IS_VALID:		is given reset control is valid?
  */
 enum ccu_flags {
 	CCU_CLK_F_IS_VALID		= BIT(0),
+	CCU_RST_F_IS_VALID		= BIT(1),
 };
 
 /**
@@ -34,13 +36,33 @@ struct ccu_clk_gate {
 	.flags = CCU_CLK_F_IS_VALID,		\
 }
 
+/**
+ * struct ccu_reset - ccu reset
+ * @off:	reset offset
+ * @bit:	reset bit
+ * @flags:	ccu reset control flags
+ */
+struct ccu_reset {
+	u16 off;
+	u32 bit;
+	enum ccu_flags flags;
+};
+
+#define RESET(_off, _bit) {			\
+	.off = _off,				\
+	.bit = _bit,				\
+	.flags = CCU_RST_F_IS_VALID,		\
+}
+
 /**
  * struct ccu_desc - clock control unit descriptor
  *
  * @gates:	clock gates
+ * @resets:	reset unit
  */
 struct ccu_desc {
 	const struct ccu_clk_gate *gates;
+	const struct ccu_reset *resets;
 };
 
 /**
@@ -62,4 +84,13 @@ int sunxi_clk_probe(struct udevice *dev);
 
 extern struct clk_ops sunxi_clk_ops;
 
+/**
+ * sunxi_reset_bind() - reset binding
+ *
+ * @dev:       reset device
+ * @count:     reset count
+ * @return 0 success, or error value
+ */
+int sunxi_reset_bind(struct udevice *dev, ulong count);
+
 #endif /* _ASM_ARCH_CCU_H */

drivers/clk/sunxi/Kconfig

@@ -1,6 +1,7 @@
 config CLK_SUNXI
 	bool "Clock support for Allwinner SoCs"
 	depends on CLK && ARCH_SUNXI
+	select DM_RESET
 	default y
 	help
 	  This enables support for common clock driver API on Allwinner

drivers/clk/sunxi/clk_a64.c

@@ -10,6 +10,7 @@
 #include <errno.h>
 #include <asm/arch/ccu.h>
 #include <dt-bindings/clock/sun50i-a64-ccu.h>
+#include <dt-bindings/reset/sun50i-a64-ccu.h>
 
 static const struct ccu_clk_gate a64_gates[] = {
 	[CLK_BUS_OTG]		= GATE(0x060, BIT(23)),
@@ -26,10 +27,28 @@ static const struct ccu_clk_gate a64_gates[] = {
 	[CLK_USB_OHCI1]		= GATE(0x0cc, BIT(17)),
 };
 
+static const struct ccu_reset a64_resets[] = {
+	[RST_USB_PHY0]          = RESET(0x0cc, BIT(0)),
+	[RST_USB_PHY1]          = RESET(0x0cc, BIT(1)),
+	[RST_USB_HSIC]          = RESET(0x0cc, BIT(2)),
+
+	[RST_BUS_OTG]           = RESET(0x2c0, BIT(23)),
+	[RST_BUS_EHCI0]         = RESET(0x2c0, BIT(24)),
+	[RST_BUS_EHCI1]         = RESET(0x2c0, BIT(25)),
+	[RST_BUS_OHCI0]         = RESET(0x2c0, BIT(28)),
+	[RST_BUS_OHCI1]         = RESET(0x2c0, BIT(29)),
+};
+
 static const struct ccu_desc a64_ccu_desc = {
 	.gates = a64_gates,
+	.resets = a64_resets,
 };
 
+static int a64_clk_bind(struct udevice *dev)
+{
+	return sunxi_reset_bind(dev, ARRAY_SIZE(a64_resets));
+}
+
 static const struct udevice_id a64_ccu_ids[] = {
 	{ .compatible = "allwinner,sun50i-a64-ccu",
 	  .data = (ulong)&a64_ccu_desc },
@@ -43,4 +62,5 @@ U_BOOT_DRIVER(clk_sun50i_a64) = {
 	.priv_auto_alloc_size	= sizeof(struct ccu_priv),
 	.ops		= &sunxi_clk_ops,
 	.probe		= sunxi_clk_probe,
+	.bind		= a64_clk_bind,
 };

drivers/reset/Kconfig

@@ -113,4 +113,12 @@ config RESET_MEDIATEK
 	help
 	  Support for reset controller on MediaTek SoCs.
 
+config RESET_SUNXI
+	bool "RESET support for Allwinner SoCs"
+	depends on DM_RESET && ARCH_SUNXI
+	default y
+	help
+	  This enables support for common reset driver for
+	  Allwinner SoCs.
+
 endmenu

drivers/reset/Makefile

@@ -18,3 +18,4 @@ obj-$(CONFIG_RESET_ROCKCHIP) += reset-rockchip.o
 obj-$(CONFIG_RESET_MESON) += reset-meson.o
 obj-$(CONFIG_RESET_SOCFPGA) += reset-socfpga.o
 obj-$(CONFIG_RESET_MEDIATEK) += reset-mediatek.o
+obj-$(CONFIG_RESET_SUNXI) += reset-sunxi.o

drivers/reset/reset-sunxi.c

@@ -0,0 +1,124 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (C) 2018 Amarula Solutions.
+ * Author: Jagan Teki <jagan@amarulasolutions.com>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <reset-uclass.h>
+#include <asm/io.h>
+#include <dm/lists.h>
+#include <linux/log2.h>
+#include <asm/arch/ccu.h>
+
+struct sunxi_reset_priv {
+	void *base;
+	ulong count;
+	const struct ccu_desc *desc;
+};
+
+static const struct ccu_reset *priv_to_reset(struct sunxi_reset_priv *priv,
+					     unsigned long id)
+{
+	return	&priv->desc->resets[id];
+}
+
+static int sunxi_reset_request(struct reset_ctl *reset_ctl)
+{
+	struct sunxi_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+
+	debug("%s: (RST#%ld)\n", __func__, reset_ctl->id);
+
+	if (reset_ctl->id >= priv->count)
+		return -EINVAL;
+
+	return 0;
+}
+
+static int sunxi_reset_free(struct reset_ctl *reset_ctl)
+{
+	debug("%s: (RST#%ld)\n", __func__, reset_ctl->id);
+
+	return 0;
+}
+
+static int sunxi_set_reset(struct reset_ctl *reset_ctl, bool on)
+{
+	struct sunxi_reset_priv *priv = dev_get_priv(reset_ctl->dev);
+	const struct ccu_reset *reset = priv_to_reset(priv, reset_ctl->id);
+	u32 reg;
+
+	if (!(reset->flags & CCU_RST_F_IS_VALID)) {
+		printf("%s: (RST#%ld) unhandled\n", __func__, reset_ctl->id);
+		return 0;
+	}
+
+	debug("%s: (RST#%ld) off#0x%x, BIT(%d)\n", __func__,
+	      reset_ctl->id, reset->off, ilog2(reset->bit));
+
+	reg = readl(priv->base + reset->off);
+	if (on)
+		reg |= reset->bit;
+	else
+		reg &= ~reset->bit;
+
+	writel(reg, priv->base + reset->off);
+
+	return 0;
+}
+
+static int sunxi_reset_assert(struct reset_ctl *reset_ctl)
+{
+	return sunxi_set_reset(reset_ctl, false);
+}
+
+static int sunxi_reset_deassert(struct reset_ctl *reset_ctl)
+{
+	return sunxi_set_reset(reset_ctl, true);
+}
+
+struct reset_ops sunxi_reset_ops = {
+	.request = sunxi_reset_request,
+	.free = sunxi_reset_free,
+	.rst_assert = sunxi_reset_assert,
+	.rst_deassert = sunxi_reset_deassert,
+};
+
+static int sunxi_reset_probe(struct udevice *dev)
+{
+	struct sunxi_reset_priv *priv = dev_get_priv(dev);
+
+	priv->base = dev_read_addr_ptr(dev);
+
+	return 0;
+}
+
+int sunxi_reset_bind(struct udevice *dev, ulong count)
+{
+	struct udevice *rst_dev;
+	struct sunxi_reset_priv *priv;
+	int ret;
+
+	ret = device_bind_driver_to_node(dev, "sunxi_reset", "reset",
+					 dev_ofnode(dev), &rst_dev);
+	if (ret) {
+		debug("failed to bind sunxi_reset driver (ret=%d)\n", ret);
+		return ret;
+	}
+	priv = malloc(sizeof(struct sunxi_reset_priv));
+	priv->count = count;
+	priv->desc = (const struct ccu_desc *)dev_get_driver_data(dev);
+	rst_dev->priv = priv;
+
+	return 0;
+}
+
+U_BOOT_DRIVER(sunxi_reset) = {
+	.name		= "sunxi_reset",
+	.id		= UCLASS_RESET,
+	.ops		= &sunxi_reset_ops,
+	.probe		= sunxi_reset_probe,
+	.priv_auto_alloc_size = sizeof(struct sunxi_reset_priv),
+};