ARC: HSDK: introduce reset driver

Introduce reset driver for Synopsys ARC HSDK SoC

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>

drivers/reset/Kconfig

@@ -91,6 +91,13 @@ config RESET_ROCKCHIP
 	  though is that some reset signals, like I2C or MISC reset multiple
 	  devices.
 
+config RESET_HSDK
+	bool "Synopsys HSDK Reset Driver"
+	depends on DM_RESET && TARGET_HSDK
+	default y
+	help
+	  This enables the reset controller driver for HSDK board.
+
 config RESET_MESON
 	bool "Reset controller driver for Amlogic Meson SoCs"
 	depends on DM_RESET && ARCH_MESON

drivers/reset/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_STM32_RESET) += stm32-reset.o
 obj-$(CONFIG_TEGRA_CAR_RESET) += tegra-car-reset.o
 obj-$(CONFIG_TEGRA186_RESET) += tegra186-reset.o
 obj-$(CONFIG_RESET_TI_SCI) += reset-ti-sci.o
+obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
 obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
 obj-$(CONFIG_RESET_UNIPHIER) += reset-uniphier.o
 obj-$(CONFIG_AST2500_RESET) += ast2500-reset.o

drivers/reset/reset-hsdk.c

@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * HSDK SoC Reset Controller driver
+ *
+ * Copyright (C) 2019 Synopsys, Inc. All rights reserved.
+ * Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
+ */
+
+#include <asm/io.h>
+#include <common.h>
+#include <dm.h>
+#include <linux/iopoll.h>
+#include <reset-uclass.h>
+
+struct hsdk_rst {
+	void __iomem		*regs_ctl;
+	void __iomem		*regs_rst;
+};
+
+static const u32 rst_map[] = {
+	BIT(16), /* APB_RST  */
+	BIT(17), /* AXI_RST  */
+	BIT(18), /* ETH_RST  */
+	BIT(19), /* USB_RST  */
+	BIT(20), /* SDIO_RST */
+	BIT(21), /* HDMI_RST */
+	BIT(22), /* GFX_RST  */
+	BIT(25), /* DMAC_RST */
+	BIT(31), /* EBI_RST  */
+};
+
+#define HSDK_MAX_RESETS			ARRAY_SIZE(rst_map)
+
+#define CGU_SYS_RST_CTRL		0x0
+#define CGU_IP_SW_RESET			0x0
+#define CGU_IP_SW_RESET_DELAY_SHIFT	16
+#define CGU_IP_SW_RESET_DELAY_MASK	GENMASK(31, CGU_IP_SW_RESET_DELAY_SHIFT)
+#define CGU_IP_SW_RESET_DELAY		0
+#define CGU_IP_SW_RESET_RESET		BIT(0)
+#define SW_RESET_TIMEOUT		10000
+
+static void hsdk_reset_config(struct hsdk_rst *rst, unsigned long id)
+{
+	writel(rst_map[id], rst->regs_ctl + CGU_SYS_RST_CTRL);
+}
+
+static int hsdk_reset_do(struct hsdk_rst *rst)
+{
+	u32 reg;
+
+	reg = readl(rst->regs_rst + CGU_IP_SW_RESET);
+	reg &= ~CGU_IP_SW_RESET_DELAY_MASK;
+	reg |= CGU_IP_SW_RESET_DELAY << CGU_IP_SW_RESET_DELAY_SHIFT;
+	reg |= CGU_IP_SW_RESET_RESET;
+	writel(reg, rst->regs_rst + CGU_IP_SW_RESET);
+
+	/* wait till reset bit is back to 0 */
+	return readl_poll_timeout(rst->regs_rst + CGU_IP_SW_RESET, reg,
+		!(reg & CGU_IP_SW_RESET_RESET), SW_RESET_TIMEOUT);
+}
+
+static int hsdk_reset_reset(struct reset_ctl *rst_ctl)
+{
+	struct udevice *dev = rst_ctl->dev;
+	struct hsdk_rst *rst = dev_get_priv(dev);
+
+	if (rst_ctl->id >= HSDK_MAX_RESETS)
+		return -EINVAL;
+
+	debug("%s(reset_ctl=%p) (dev=%p, id=%lu)\n", __func__, rst_ctl,
+	      rst_ctl->dev, rst_ctl->id);
+
+	hsdk_reset_config(rst, rst_ctl->id);
+	return hsdk_reset_do(rst);
+}
+
+static int hsdk_reset_noop(struct reset_ctl *rst_ctl)
+{
+	return 0;
+}
+
+static const struct reset_ops hsdk_reset_ops = {
+	.request	= hsdk_reset_noop,
+	.free		= hsdk_reset_noop,
+	.rst_assert	= hsdk_reset_noop,
+	.rst_deassert	= hsdk_reset_reset,
+};
+
+static const struct udevice_id hsdk_reset_dt_match[] = {
+	{ .compatible = "snps,hsdk-reset" },
+	{ },
+};
+
+static int hsdk_reset_probe(struct udevice *dev)
+{
+	struct hsdk_rst *rst = dev_get_priv(dev);
+
+	rst->regs_ctl = dev_remap_addr_index(dev, 0);
+	if (!rst->regs_ctl)
+		return -EINVAL;
+
+	rst->regs_rst = dev_remap_addr_index(dev, 1);
+	if (!rst->regs_rst)
+		return -EINVAL;
+
+	return 0;
+}
+
+U_BOOT_DRIVER(hsdk_reset) = {
+	.name = "hsdk-reset",
+	.id = UCLASS_RESET,
+	.of_match = hsdk_reset_dt_match,
+	.ops = &hsdk_reset_ops,
+	.probe = hsdk_reset_probe,
+	.priv_auto_alloc_size = sizeof(struct hsdk_rst),
+};

include/dt-bindings/reset/snps,hsdk-reset.h

@@ -0,0 +1,17 @@
+/**
+ * This header provides index for the HSDK reset controller.
+ */
+#ifndef _DT_BINDINGS_RESET_CONTROLLER_SNPS_HSDK
+#define _DT_BINDINGS_RESET_CONTROLLER_SNPS_HSDK
+
+#define HSDK_APB_RESET	0
+#define HSDK_AXI_RESET	1
+#define HSDK_ETH_RESET	2
+#define HSDK_USB_RESET	3
+#define HSDK_SDIO_RESET	4
+#define HSDK_HDMI_RESET	5
+#define HSDK_GFX_RESET	6
+#define HSDK_DMAC_RESET	7
+#define HSDK_EBI_RESET	8
+
+#endif /*_DT_BINDINGS_RESET_CONTROLLER_SNPS_HSDK*/