keystone-reset.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * TI keystone reboot driver
  4 *
  5 * Copyright (C) 2014 Texas Instruments Incorporated. https://www.ti.com/
  6 *
  7 * Author: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>
  8 */
  9
 10#include <linux/io.h>
 11#include <linux/module.h>
 12#include <linux/notifier.h>
 13#include <linux/platform_device.h>
 14#include <linux/reboot.h>
 15#include <linux/regmap.h>
 16#include <linux/mfd/syscon.h>
 17#include <linux/of.h>
 18
 19#define RSCTRL_RG			0x4
 20#define RSCFG_RG			0x8
 21#define RSISO_RG			0xc
 22
 23#define RSCTRL_KEY_MASK			0x0000ffff
 24#define RSCTRL_RESET_MASK		BIT(16)
 25#define RSCTRL_KEY			0x5a69
 26
 27#define RSMUX_OMODE_MASK		0xe
 28#define RSMUX_OMODE_RESET_ON		0xa
 29#define RSMUX_OMODE_RESET_OFF		0x0
 30#define RSMUX_LOCK_SET			0x1
 31
 32#define RSCFG_RSTYPE_SOFT		0x300f
 33#define RSCFG_RSTYPE_HARD		0x0
 34
 35#define WDT_MUX_NUMBER			0x4
 36
 37static int rspll_offset;
 38static struct regmap *pllctrl_regs;
 39
 40/**
 41 * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG
 42 * To be able to access to RSCTRL, RSCFG registers
 43 * we have to write a key before
 44 */
 45static inline int rsctrl_enable_rspll_write(void)
 46{
 47	return regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
 48				  RSCTRL_KEY_MASK, RSCTRL_KEY);
 49}
 50
 51static int rsctrl_restart_handler(struct notifier_block *this,
 52				  unsigned long mode, void *cmd)
 53{
 54	/* enable write access to RSTCTRL */
 55	rsctrl_enable_rspll_write();
 56
 57	/* reset the SOC */
 58	regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,
 59			   RSCTRL_RESET_MASK, 0);
 60
 61	return NOTIFY_DONE;
 62}
 63
 64static struct notifier_block rsctrl_restart_nb = {
 65	.notifier_call = rsctrl_restart_handler,
 66	.priority = 128,
 67};
 68
 69static const struct of_device_id rsctrl_of_match[] = {
 70	{.compatible = "ti,keystone-reset", },
 71	{},
 72};
 73MODULE_DEVICE_TABLE(of, rsctrl_of_match);
 74
 75static int rsctrl_probe(struct platform_device *pdev)
 76{
 77	int i;
 78	int ret;
 79	u32 val;
 80	unsigned int rg;
 81	u32 rsmux_offset;
 82	struct regmap *devctrl_regs;
 83	struct device *dev = &pdev->dev;
 84	struct device_node *np = dev->of_node;
 85
 86	if (!np)
 87		return -ENODEV;
 88
 89	/* get regmaps */
 90	pllctrl_regs = syscon_regmap_lookup_by_phandle_args(np, "ti,syscon-pll",
 91							    1, &rspll_offset);
 92	if (IS_ERR(pllctrl_regs))
 93		return PTR_ERR(pllctrl_regs);
 94
 95	devctrl_regs = syscon_regmap_lookup_by_phandle_args(np, "ti,syscon-dev",
 96							    1, &rsmux_offset);
 97	if (IS_ERR(devctrl_regs))
 98		return PTR_ERR(devctrl_regs);
 99
100	/* set soft/hard reset */
101	val = of_property_read_bool(np, "ti,soft-reset");
102	val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD;
103
104	ret = rsctrl_enable_rspll_write();
105	if (ret)
106		return ret;
107
108	ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val);
109	if (ret)
110		return ret;
111
112	/* disable a reset isolation for all module clocks */
113	ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0);
114	if (ret)
115		return ret;
116
117	/* enable a reset for watchdogs from wdt-list */
118	for (i = 0; i < WDT_MUX_NUMBER; i++) {
119		ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val);
120		if (ret == -EOVERFLOW && !i) {
121			dev_err(dev, "ti,wdt-list property has to contain at"
122				"least one entry\n");
123			return -EINVAL;
124		} else if (ret) {
125			break;
126		}
127
128		if (val >= WDT_MUX_NUMBER) {
129			dev_err(dev, "ti,wdt-list property can contain "
130				"only numbers < 4\n");
131			return -EINVAL;
132		}
133
134		rg = rsmux_offset + val * 4;
135
136		ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK,
137					 RSMUX_OMODE_RESET_ON |
138					 RSMUX_LOCK_SET);
139		if (ret)
140			return ret;
141	}
142
143	ret = register_restart_handler(&rsctrl_restart_nb);
144	if (ret)
145		dev_err(dev, "cannot register restart handler (err=%d)\n", ret);
146
147	return ret;
148}
149
150static struct platform_driver rsctrl_driver = {
151	.probe = rsctrl_probe,
152	.driver = {
153		.name = KBUILD_MODNAME,
154		.of_match_table = rsctrl_of_match,
155	},
156};
157module_platform_driver(rsctrl_driver);
158
159MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
160MODULE_DESCRIPTION("Texas Instruments keystone reset driver");
161MODULE_ALIAS("platform:" KBUILD_MODNAME);