[PATCH v3 2/2] reset: eswin: Add eic7700 reset driver

[dongxuyang@eswincomputing.com]

From: Xuyang Dong <dongxuyang@eswincomputing.com>

Add support for reset controller in eic7700 series chips.
Provide functionality for asserting and deasserting resets
on the chip.

Signed-off-by: Yifeng Huang <huangyifeng@eswincomputing.com>
Signed-off-by: Xuyang Dong <dongxuyang@eswincomputing.com>
---
 drivers/reset/Kconfig         |  10 ++
 drivers/reset/Makefile        |   1 +
 drivers/reset/reset-eic7700.c | 243 ++++++++++++++++++++++++++++++++++
 3 files changed, 254 insertions(+)
 create mode 100644 drivers/reset/reset-eic7700.c

diff --git a/drivers/reset/Kconfig b/drivers/reset/Kconfig
index d85be5899da6..82f829f4c9f0 100644
--- a/drivers/reset/Kconfig
+++ b/drivers/reset/Kconfig
@@ -66,6 +66,16 @@ config RESET_BRCMSTB_RESCAL
 	  This enables the RESCAL reset controller for SATA, PCIe0, or PCIe1 on
 	  BCM7216.

+config RESET_EIC7700
+	bool "Reset controller driver for ESWIN SoCs"
+	depends on ARCH_ESWIN || COMPILE_TEST
+	default ARCH_ESWIN
+	help
+	  This enables the reset controller driver for ESWIN SoCs. This driver is
+	  specific to ESWIN SoCs and should only be enabled if using such hardware.
+	  The driver supports eic7700 series chips and provides functionality for
+	  asserting and deasserting resets on the chip.
+
 config RESET_EYEQ
 	bool "Mobileye EyeQ reset controller"
 	depends on MACH_EYEQ5 || MACH_EYEQ6H || COMPILE_TEST
diff --git a/drivers/reset/Makefile b/drivers/reset/Makefile
index 91e6348e3351..ceafbad0555c 100644
--- a/drivers/reset/Makefile
+++ b/drivers/reset/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_RESET_BCM6345) += reset-bcm6345.o
 obj-$(CONFIG_RESET_BERLIN) += reset-berlin.o
 obj-$(CONFIG_RESET_BRCMSTB) += reset-brcmstb.o
 obj-$(CONFIG_RESET_BRCMSTB_RESCAL) += reset-brcmstb-rescal.o
+obj-$(CONFIG_RESET_EIC7700) += reset-eic7700.o
 obj-$(CONFIG_RESET_EYEQ) += reset-eyeq.o
 obj-$(CONFIG_RESET_GPIO) += reset-gpio.o
 obj-$(CONFIG_RESET_HSDK) += reset-hsdk.o
diff --git a/drivers/reset/reset-eic7700.c b/drivers/reset/reset-eic7700.c
new file mode 100644
index 000000000000..61513746c06c
--- /dev/null
+++ b/drivers/reset/reset-eic7700.c
@@ -0,0 +1,243 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2024, Beijing ESWIN Computing Technology Co., Ltd.. All rights reserved.
+ *
+ * ESWIN Reset Driver
+ *
+ * Authors:
+ *	Yifeng Huang <huangyifeng@eswincomputing.com>
+ *	Xuyang Dong <dongxuyang@eswincomputing.com>
+ */
+
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/reset-controller.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+#define SYSCRG_CLEAR_BOOT_INFO_OFFSET 0x30C
+#define CLEAR_BOOT_FLAG_BIT BIT(0)
+#define SYSCRG_RESET_OFFSET 0x400
+
+/**
+ * struct eswin_reset_data - reset controller information structure
+ * @rcdev: reset controller entity
+ * @dev: reset controller device pointer
+ * @idr: idr structure for mapping ids to reset control structures
+ * @regmap: reset controller device register map
+ */
+struct eswin_reset_data {
+	struct reset_controller_dev rcdev;
+	struct device *dev;
+	struct idr idr;
+	struct regmap *regmap;
+};
+
+/**
+ * struct eswin_reset_control - reset control structure
+ * @dev_id: SoC-specific device identifier
+ * @reset_bit: reset mask to use for toggling reset
+ */
+struct eswin_reset_control {
+	u32 dev_id;
+	u32 reset_bit;
+};
+
+static const struct regmap_config eswin_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.max_register = 0x8000000,
+};
+
+#define to_eswin_reset_data(p) container_of((p), struct eswin_reset_data, rcdev)
+
+/**
+ * eswin_reset_set() - program a device's reset
+ * @rcdev: reset controller entity
+ * @id: ID of the reset to toggle
+ * @assert: boolean flag to indicate assert or deassert
+ *
+ * This is a common internal function used to assert or deassert a device's
+ * reset by clear and set the reset bit. The device's reset is asserted if the
+ * @assert argument is true, or deasserted if @assert argument is false.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int eswin_reset_set(struct reset_controller_dev *rcdev, unsigned long id,
+			   bool assert)
+{
+	struct eswin_reset_data *data = to_eswin_reset_data(rcdev);
+	struct eswin_reset_control *control;
+	int ret;
+
+	control = idr_find(&data->idr, id);
+
+	if (!control)
+		return -EINVAL;
+
+	if (assert)
+		ret = regmap_clear_bits(data->regmap, SYSCRG_RESET_OFFSET +
+						       control->dev_id * sizeof(u32),
+							   BIT(control->reset_bit));
+	else
+		ret = regmap_set_bits(data->regmap, SYSCRG_RESET_OFFSET +
+						     control->dev_id * sizeof(u32),
+						     BIT(control->reset_bit));
+
+	return ret;
+}
+
+static int eswin_reset_assert(struct reset_controller_dev *rcdev,
+			      unsigned long id)
+{
+	return eswin_reset_set(rcdev, id, true);
+}
+
+static int eswin_reset_deassert(struct reset_controller_dev *rcdev,
+				unsigned long id)
+{
+	return eswin_reset_set(rcdev, id, false);
+}
+
+static int eswin_reset_reset(struct reset_controller_dev *rcdev,
+			     unsigned long id)
+{
+	int ret;
+
+	ret = eswin_reset_assert(rcdev, id);
+	if (ret != 0)
+		return ret;
+
+	usleep_range(10, 15);
+	ret = eswin_reset_deassert(rcdev, id);
+	if (ret != 0)
+		return ret;
+
+	return 0;
+}
+
+static const struct reset_control_ops eswin_reset_ops = {
+	.reset = eswin_reset_reset,
+	.assert = eswin_reset_assert,
+	.deassert = eswin_reset_deassert,
+};
+
+static int eswin_reset_of_xlate_lookup_id(int id, void *p, void *data)
+{
+	struct of_phandle_args *reset_spec = data;
+	struct eswin_reset_control *slot_control = p;
+
+	if (reset_spec->args[0] == slot_control->dev_id &&
+	    reset_spec->args[1] == slot_control->reset_bit)
+		return id;
+
+	return 0;
+}
+
+/**
+ * eswin_reset_of_xlate() - translate a set of OF arguments to a reset ID
+ * @rcdev: reset controller entity
+ * @reset_spec: OF reset argument specifier
+ *
+ * This function performs the translation of the reset argument specifier
+ * values defined in a reset consumer device node. The function allocates a
+ * reset control structure for that device reset, and will be used by the
+ * driver for performing any reset functions on that reset. An idr structure
+ * is allocated and used to map to the reset control structure. This idr
+ * is used by the driver to do reset lookups.
+ *
+ * Return: 0 for successful request, else a corresponding error value
+ */
+static int eswin_reset_of_xlate(struct reset_controller_dev *rcdev,
+				const struct of_phandle_args *reset_spec)
+{
+	struct eswin_reset_data *data = to_eswin_reset_data(rcdev);
+	struct eswin_reset_control *control;
+	int ret;
+
+	if (WARN_ON(reset_spec->args_count != rcdev->of_reset_n_cells))
+		return -EINVAL;
+
+	ret = idr_for_each(&data->idr, eswin_reset_of_xlate_lookup_id,
+			   (void *)reset_spec);
+	if (ret)
+		return ret;
+
+	control = devm_kzalloc(data->dev, sizeof(*control), GFP_KERNEL);
+	if (!control)
+		return -ENOMEM;
+
+	control->dev_id = reset_spec->args[0];
+	control->reset_bit = reset_spec->args[1];
+
+	return idr_alloc(&data->idr, control, 0, 0, GFP_KERNEL);
+}
+
+static const struct of_device_id eswin_reset_dt_ids[] = {
+	{
+		.compatible = "eswin,eic7700-reset",
+	},
+	{ /* sentinel */ }
+};
+
+static int eswin_reset_probe(struct platform_device *pdev)
+{
+	struct eswin_reset_data *data;
+	struct device *dev = &pdev->dev;
+	void __iomem *base;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
+
+	data->regmap = devm_regmap_init_mmio(dev, base, &eswin_regmap_config);
+	if (IS_ERR(data->regmap))
+		return dev_err_probe(dev, PTR_ERR(data->regmap), "failed to get regmap!\n");
+
+	platform_set_drvdata(pdev, data);
+
+	data->rcdev.owner = THIS_MODULE;
+	data->rcdev.ops = &eswin_reset_ops;
+	data->rcdev.of_node = pdev->dev.of_node;
+	data->rcdev.of_reset_n_cells = 2;
+	data->rcdev.of_xlate = eswin_reset_of_xlate;
+	data->rcdev.dev = &pdev->dev;
+	data->dev = &pdev->dev;
+	idr_init(&data->idr);
+
+	/* clear boot flag so u84 and scpu could be reseted by software */
+	regmap_set_bits(data->regmap, SYSCRG_CLEAR_BOOT_INFO_OFFSET,
+			CLEAR_BOOT_FLAG_BIT);
+	msleep(50);
+
+	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
+}
+
+static void eswin_reset_remove(struct platform_device *pdev)
+{
+	struct eswin_reset_data *data = platform_get_drvdata(pdev);
+
+	idr_destroy(&data->idr);
+}
+
+static struct platform_driver eswin_reset_driver = {
+	.probe	= eswin_reset_probe,
+	.remove = eswin_reset_remove,
+	.driver = {
+		.name		= "eswin-reset",
+		.of_match_table	= eswin_reset_dt_ids,
+	},
+};
+
+static int __init eswin_reset_init(void)
+{
+	return platform_driver_register(&eswin_reset_driver);
+}
+arch_initcall(eswin_reset_init);
--
2.17.1