1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * Copyright (C) 2018, Intel Corporation
  4 * Copied from reset-sunxi.c
  5 */
  6
  7#include <linux/err.h>
  8#include <linux/io.h>
  9#include <linux/init.h>
 10#include <linux/of.h>
 11#include <linux/of_address.h>
 12#include <linux/platform_device.h>
 13#include <linux/reset-controller.h>
 14#include <linux/reset/reset-simple.h>
 15#include <linux/reset/socfpga.h>
 16#include <linux/slab.h>
 17#include <linux/spinlock.h>
 18#include <linux/types.h>
 19
 20#define SOCFPGA_NR_BANKS	8
 21
 22static int a10_reset_init(struct device_node *np)
 23{
 24	struct reset_simple_data *data;
 25	struct resource res;
 26	resource_size_t size;
 27	int ret;
 28	u32 reg_offset = 0x10;
 29
 30	data = kzalloc(sizeof(*data), GFP_KERNEL);
 31	if (!data)
 32		return -ENOMEM;
 33
 34	ret = of_address_to_resource(np, 0, &res);
 35	if (ret)
 36		goto err_alloc;
 37
 38	size = resource_size(&res);
 39	if (!request_mem_region(res.start, size, np->name)) {
 40		ret = -EBUSY;
 41		goto err_alloc;
 42	}
 43
 44	data->membase = ioremap(res.start, size);
 45	if (!data->membase) {
 46		ret = -ENOMEM;
 47		goto release_region;
 48	}
 49
 50	if (of_property_read_u32(np, "altr,modrst-offset", &reg_offset))
 51		pr_warn("missing altr,modrst-offset property, assuming 0x10\n");
 52	data->membase += reg_offset;
 53
 54	spin_lock_init(&data->lock);
 55
 56	data->rcdev.owner = THIS_MODULE;
 57	data->rcdev.nr_resets = SOCFPGA_NR_BANKS * 32;
 58	data->rcdev.ops = &reset_simple_ops;
 59	data->rcdev.of_node = np;
 60	data->status_active_low = true;
 61
 62	ret = reset_controller_register(&data->rcdev);
 63	if (ret)
 64		pr_err("unable to register device\n");
 65
 66	return ret;
 67
 68release_region:
 69	release_mem_region(res.start, size);
 70
 71err_alloc:
 72	kfree(data);
 73	return ret;
 74};
 75
 76/*
 77 * These are the reset controller we need to initialize early on in
 78 * our system, before we can even think of using a regular device
 79 * driver for it.
 80 * The controllers that we can register through the regular device
 81 * model are handled by the simple reset driver directly.
 82 */
 83static const struct of_device_id socfpga_early_reset_dt_ids[] __initconst = {
 84	{ .compatible = "altr,rst-mgr", },
 85	{ /* sentinel */ },
 86};
 87
 88void __init socfpga_reset_init(void)
 89{
 90	struct device_node *np;
 91
 92	for_each_matching_node(np, socfpga_early_reset_dt_ids)
 93		a10_reset_init(np);
 94}
 95
 96/*
 97 * The early driver is problematic, because it doesn't register
 98 * itself as a driver. This causes certain device links to prevent
 99 * consumer devices from probing. The hacky solution is to register
100 * an empty driver, whose only job is to attach itself to the reset
101 * manager and call probe.
102 */
103static const struct of_device_id socfpga_reset_dt_ids[] = {
104	{ .compatible = "altr,rst-mgr", },
105	{ /* sentinel */ },
106};
107
108static int reset_simple_probe(struct platform_device *pdev)
109{
110	return 0;
111}
112
113static struct platform_driver reset_socfpga_driver = {
114	.probe	= reset_simple_probe,
115	.driver = {
116		.name		= "socfpga-reset",
117		.of_match_table	= socfpga_reset_dt_ids,
118	},
119};
120builtin_platform_driver(reset_socfpga_driver);