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 37 static int rspll_offset; 38 static 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 */ 45 static 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 51 static 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 64 static struct notifier_block rsctrl_restart_nb = { 65 .notifier_call = rsctrl_restart_handler, 66 .priority = 128, 67 }; 68 69 static const struct of_device_id rsctrl_of_match[] = { 70 {.compatible = "ti,keystone-reset", }, 71 {}, 72 }; 73 MODULE_DEVICE_TABLE(of, rsctrl_of_match); 74 75 static 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(np, "ti,syscon-pll"); 91 if (IS_ERR(pllctrl_regs)) 92 return PTR_ERR(pllctrl_regs); 93 94 devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev"); 95 if (IS_ERR(devctrl_regs)) 96 return PTR_ERR(devctrl_regs); 97 98 ret = of_property_read_u32_index(np, "ti,syscon-pll", 1, &rspll_offset); 99 if (ret) { 100 dev_err(dev, "couldn't read the reset pll offset!\n"); 101 return -EINVAL; 102 } 103 104 ret = of_property_read_u32_index(np, "ti,syscon-dev", 1, &rsmux_offset); 105 if (ret) { 106 dev_err(dev, "couldn't read the rsmux offset!\n"); 107 return -EINVAL; 108 } 109 110 /* set soft/hard reset */ 111 val = of_property_read_bool(np, "ti,soft-reset"); 112 val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD; 113 114 ret = rsctrl_enable_rspll_write(); 115 if (ret) 116 return ret; 117 118 ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val); 119 if (ret) 120 return ret; 121 122 /* disable a reset isolation for all module clocks */ 123 ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0); 124 if (ret) 125 return ret; 126 127 /* enable a reset for watchdogs from wdt-list */ 128 for (i = 0; i < WDT_MUX_NUMBER; i++) { 129 ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val); 130 if (ret == -EOVERFLOW && !i) { 131 dev_err(dev, "ti,wdt-list property has to contain at" 132 "least one entry\n"); 133 return -EINVAL; 134 } else if (ret) { 135 break; 136 } 137 138 if (val >= WDT_MUX_NUMBER) { 139 dev_err(dev, "ti,wdt-list property can contain " 140 "only numbers < 4\n"); 141 return -EINVAL; 142 } 143 144 rg = rsmux_offset + val * 4; 145 146 ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK, 147 RSMUX_OMODE_RESET_ON | 148 RSMUX_LOCK_SET); 149 if (ret) 150 return ret; 151 } 152 153 ret = register_restart_handler(&rsctrl_restart_nb); 154 if (ret) 155 dev_err(dev, "cannot register restart handler (err=%d)\n", ret); 156 157 return ret; 158 } 159 160 static struct platform_driver rsctrl_driver = { 161 .probe = rsctrl_probe, 162 .driver = { 163 .name = KBUILD_MODNAME, 164 .of_match_table = rsctrl_of_match, 165 }, 166 }; 167 module_platform_driver(rsctrl_driver); 168 169 MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>"); 170 MODULE_DESCRIPTION("Texas Instruments keystone reset driver"); 171 MODULE_ALIAS("platform:" KBUILD_MODNAME); 172