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 RSTYPE_RG 0x0 20 #define RSCTRL_RG 0x4 21 #define RSCFG_RG 0x8 22 #define RSISO_RG 0xc 23 24 #define RSCTRL_KEY_MASK 0x0000ffff 25 #define RSCTRL_RESET_MASK BIT(16) 26 #define RSCTRL_KEY 0x5a69 27 28 #define RSMUX_OMODE_MASK 0xe 29 #define RSMUX_OMODE_RESET_ON 0xa 30 #define RSMUX_OMODE_RESET_OFF 0x0 31 #define RSMUX_LOCK_MASK 0x1 32 #define RSMUX_LOCK_SET 0x1 33 34 #define RSCFG_RSTYPE_SOFT 0x300f 35 #define RSCFG_RSTYPE_HARD 0x0 36 37 #define WDT_MUX_NUMBER 0x4 38 39 static int rspll_offset; 40 static struct regmap *pllctrl_regs; 41 42 /** 43 * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG 44 * To be able to access to RSCTRL, RSCFG registers 45 * we have to write a key before 46 */ 47 static 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 53 static 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 66 static struct notifier_block rsctrl_restart_nb = { 67 .notifier_call = rsctrl_restart_handler, 68 .priority = 128, 69 }; 70 71 static const struct of_device_id rsctrl_of_match[] = { 72 {.compatible = "ti,keystone-reset", }, 73 {}, 74 }; 75 MODULE_DEVICE_TABLE(of, rsctrl_of_match); 76 77 static 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 } 161 162 static struct platform_driver rsctrl_driver = { 163 .probe = rsctrl_probe, 164 .driver = { 165 .name = KBUILD_MODNAME, 166 .of_match_table = rsctrl_of_match, 167 }, 168 }; 169 module_platform_driver(rsctrl_driver); 170 171 MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>"); 172 MODULE_DESCRIPTION("Texas Instruments keystone reset driver"); 173 MODULE_ALIAS("platform:" KBUILD_MODNAME); 174