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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * TI keystone reboot driver4 *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 RSTYPE_RG 0x020#define RSCTRL_RG 0x421#define RSCFG_RG 0x822#define RSISO_RG 0xc23 24#define RSCTRL_KEY_MASK 0x0000ffff25#define RSCTRL_RESET_MASK BIT(16)26#define RSCTRL_KEY 0x5a6927 28#define RSMUX_OMODE_MASK 0xe29#define RSMUX_OMODE_RESET_ON 0xa30#define RSMUX_OMODE_RESET_OFF 0x031#define RSMUX_LOCK_MASK 0x132#define RSMUX_LOCK_SET 0x133 34#define RSCFG_RSTYPE_SOFT 0x300f35#define RSCFG_RSTYPE_HARD 0x036 37#define WDT_MUX_NUMBER 0x438 39static int rspll_offset;40static struct regmap *pllctrl_regs;41 42/**43 * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG44 * To be able to access to RSCTRL, RSCFG registers45 * we have to write a key before46 */47static inline int rsctrl_enable_rspll_write(void)48{49 return regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,50 RSCTRL_KEY_MASK, RSCTRL_KEY);51}52 53static int rsctrl_restart_handler(struct notifier_block *this,54 unsigned long mode, void *cmd)55{56 /* enable write access to RSTCTRL */57 rsctrl_enable_rspll_write();58 59 /* reset the SOC */60 regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG,61 RSCTRL_RESET_MASK, 0);62 63 return NOTIFY_DONE;64}65 66static struct notifier_block rsctrl_restart_nb = {67 .notifier_call = rsctrl_restart_handler,68 .priority = 128,69};70 71static const struct of_device_id rsctrl_of_match[] = {72 {.compatible = "ti,keystone-reset", },73 {},74};75MODULE_DEVICE_TABLE(of, rsctrl_of_match);76 77static int rsctrl_probe(struct platform_device *pdev)78{79 int i;80 int ret;81 u32 val;82 unsigned int rg;83 u32 rsmux_offset;84 struct regmap *devctrl_regs;85 struct device *dev = &pdev->dev;86 struct device_node *np = dev->of_node;87 88 if (!np)89 return -ENODEV;90 91 /* get regmaps */92 pllctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-pll");93 if (IS_ERR(pllctrl_regs))94 return PTR_ERR(pllctrl_regs);95 96 devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev");97 if (IS_ERR(devctrl_regs))98 return PTR_ERR(devctrl_regs);99 100 ret = of_property_read_u32_index(np, "ti,syscon-pll", 1, &rspll_offset);101 if (ret) {102 dev_err(dev, "couldn't read the reset pll offset!\n");103 return -EINVAL;104 }105 106 ret = of_property_read_u32_index(np, "ti,syscon-dev", 1, &rsmux_offset);107 if (ret) {108 dev_err(dev, "couldn't read the rsmux offset!\n");109 return -EINVAL;110 }111 112 /* set soft/hard reset */113 val = of_property_read_bool(np, "ti,soft-reset");114 val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD;115 116 ret = rsctrl_enable_rspll_write();117 if (ret)118 return ret;119 120 ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val);121 if (ret)122 return ret;123 124 /* disable a reset isolation for all module clocks */125 ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0);126 if (ret)127 return ret;128 129 /* enable a reset for watchdogs from wdt-list */130 for (i = 0; i < WDT_MUX_NUMBER; i++) {131 ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val);132 if (ret == -EOVERFLOW && !i) {133 dev_err(dev, "ti,wdt-list property has to contain at"134 "least one entry\n");135 return -EINVAL;136 } else if (ret) {137 break;138 }139 140 if (val >= WDT_MUX_NUMBER) {141 dev_err(dev, "ti,wdt-list property can contain "142 "only numbers < 4\n");143 return -EINVAL;144 }145 146 rg = rsmux_offset + val * 4;147 148 ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK,149 RSMUX_OMODE_RESET_ON |150 RSMUX_LOCK_SET);151 if (ret)152 return ret;153 }154 155 ret = register_restart_handler(&rsctrl_restart_nb);156 if (ret)157 dev_err(dev, "cannot register restart handler (err=%d)\n", ret);158 159 return ret;160}161 162static struct platform_driver rsctrl_driver = {163 .probe = rsctrl_probe,164 .driver = {165 .name = KBUILD_MODNAME,166 .of_match_table = rsctrl_of_match,167 },168};169module_platform_driver(rsctrl_driver);170 171MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");172MODULE_DESCRIPTION("Texas Instruments keystone reset driver");173MODULE_ALIAS("platform:" KBUILD_MODNAME);174