1/*
  2 * Copyright 2014 Steffen Trumtrar <s.trumtrar@pengutronix.de>
  3 *
  4 * based on
  5 * Allwinner SoCs Reset Controller driver
  6 *
  7 * Copyright 2013 Maxime Ripard
  8 *
  9 * Maxime Ripard <maxime.ripard@free-electrons.com>
 10 *
 11 * This program is free software; you can redistribute it and/or modify
 12 * it under the terms of the GNU General Public License as published by
 13 * the Free Software Foundation; either version 2 of the License, or
 14 * (at your option) any later version.
 15 */
 16
 17#include <linux/err.h>
 18#include <linux/io.h>
 19#include <linux/module.h>
 20#include <linux/of.h>
 21#include <linux/platform_device.h>
 22#include <linux/reset-controller.h>
 23#include <linux/spinlock.h>
 24#include <linux/types.h>
 25
 26#define NR_BANKS		4
 27
 28struct socfpga_reset_data {
 29	spinlock_t			lock;
 30	void __iomem			*membase;
 31	u32				modrst_offset;
 32	struct reset_controller_dev	rcdev;
 33};
 34
 35static int socfpga_reset_assert(struct reset_controller_dev *rcdev,
 36				unsigned long id)
 37{
 38	struct socfpga_reset_data *data = container_of(rcdev,
 39						     struct socfpga_reset_data,
 40						     rcdev);
 41	int bank = id / BITS_PER_LONG;
 42	int offset = id % BITS_PER_LONG;
 43	unsigned long flags;
 44	u32 reg;
 45
 46	spin_lock_irqsave(&data->lock, flags);
 47
 48	reg = readl(data->membase + data->modrst_offset + (bank * NR_BANKS));
 49	writel(reg | BIT(offset), data->membase + data->modrst_offset +
 50				 (bank * NR_BANKS));
 51	spin_unlock_irqrestore(&data->lock, flags);
 52
 53	return 0;
 54}
 55
 56static int socfpga_reset_deassert(struct reset_controller_dev *rcdev,
 57				  unsigned long id)
 58{
 59	struct socfpga_reset_data *data = container_of(rcdev,
 60						     struct socfpga_reset_data,
 61						     rcdev);
 62
 63	int bank = id / BITS_PER_LONG;
 64	int offset = id % BITS_PER_LONG;
 65	unsigned long flags;
 66	u32 reg;
 67
 68	spin_lock_irqsave(&data->lock, flags);
 69
 70	reg = readl(data->membase + data->modrst_offset + (bank * NR_BANKS));
 71	writel(reg & ~BIT(offset), data->membase + data->modrst_offset +
 72				  (bank * NR_BANKS));
 73
 74	spin_unlock_irqrestore(&data->lock, flags);
 75
 76	return 0;
 77}
 78
 79static int socfpga_reset_status(struct reset_controller_dev *rcdev,
 80				unsigned long id)
 81{
 82	struct socfpga_reset_data *data = container_of(rcdev,
 83						struct socfpga_reset_data, rcdev);
 84	int bank = id / BITS_PER_LONG;
 85	int offset = id % BITS_PER_LONG;
 86	u32 reg;
 87
 88	reg = readl(data->membase + data->modrst_offset + (bank * NR_BANKS));
 89
 90	return !(reg & BIT(offset));
 91}
 92
 93static const struct reset_control_ops socfpga_reset_ops = {
 94	.assert		= socfpga_reset_assert,
 95	.deassert	= socfpga_reset_deassert,
 96	.status		= socfpga_reset_status,
 97};
 98
 99static int socfpga_reset_probe(struct platform_device *pdev)
100{
101	struct socfpga_reset_data *data;
102	struct resource *res;
103	struct device *dev = &pdev->dev;
104	struct device_node *np = dev->of_node;
105
106	/*
107	 * The binding was mainlined without the required property.
108	 * Do not continue, when we encounter an old DT.
109	 */
110	if (!of_find_property(pdev->dev.of_node, "#reset-cells", NULL)) {
111		dev_err(&pdev->dev, "%s missing #reset-cells property\n",
112			pdev->dev.of_node->full_name);
113		return -EINVAL;
114	}
115
116	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
117	if (!data)
118		return -ENOMEM;
119
120	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
121	data->membase = devm_ioremap_resource(&pdev->dev, res);
122	if (IS_ERR(data->membase))
123		return PTR_ERR(data->membase);
124
125	if (of_property_read_u32(np, "altr,modrst-offset", &data->modrst_offset)) {
126		dev_warn(dev, "missing altr,modrst-offset property, assuming 0x10!\n");
127		data->modrst_offset = 0x10;
128	}
129
130	spin_lock_init(&data->lock);
131
132	data->rcdev.owner = THIS_MODULE;
133	data->rcdev.nr_resets = NR_BANKS * BITS_PER_LONG;
134	data->rcdev.ops = &socfpga_reset_ops;
135	data->rcdev.of_node = pdev->dev.of_node;
136
137	return reset_controller_register(&data->rcdev);
138}
139
140static int socfpga_reset_remove(struct platform_device *pdev)
141{
142	struct socfpga_reset_data *data = platform_get_drvdata(pdev);
143
144	reset_controller_unregister(&data->rcdev);
145
146	return 0;
147}
148
149static const struct of_device_id socfpga_reset_dt_ids[] = {
150	{ .compatible = "altr,rst-mgr", },
151	{ /* sentinel */ },
152};
153
154static struct platform_driver socfpga_reset_driver = {
155	.probe	= socfpga_reset_probe,
156	.remove	= socfpga_reset_remove,
157	.driver = {
158		.name		= "socfpga-reset",
159		.of_match_table	= socfpga_reset_dt_ids,
160	},
161};
162module_platform_driver(socfpga_reset_driver);
163
164MODULE_AUTHOR("Steffen Trumtrar <s.trumtrar@pengutronix.de");
165MODULE_DESCRIPTION("Socfpga Reset Controller Driver");
166MODULE_LICENSE("GPL");