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 sys_off_data *data) 52 { 53 /* enable write access to RSTCTRL */ 54 rsctrl_enable_rspll_write(); 55 56 /* reset the SOC */ 57 regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG, 58 RSCTRL_RESET_MASK, 0); 59 60 return NOTIFY_DONE; 61 } 62 63 static const struct of_device_id rsctrl_of_match[] = { 64 {.compatible = "ti,keystone-reset", }, 65 {}, 66 }; 67 MODULE_DEVICE_TABLE(of, rsctrl_of_match); 68 69 static int rsctrl_probe(struct platform_device *pdev) 70 { 71 int i; 72 int ret; 73 u32 val; 74 unsigned int rg; 75 u32 rsmux_offset; 76 struct regmap *devctrl_regs; 77 struct device *dev = &pdev->dev; 78 struct device_node *np = dev->of_node; 79 80 if (!np) 81 return -ENODEV; 82 83 /* get regmaps */ 84 pllctrl_regs = syscon_regmap_lookup_by_phandle_args(np, "ti,syscon-pll", 85 1, &rspll_offset); 86 if (IS_ERR(pllctrl_regs)) 87 return PTR_ERR(pllctrl_regs); 88 89 devctrl_regs = syscon_regmap_lookup_by_phandle_args(np, "ti,syscon-dev", 90 1, &rsmux_offset); 91 if (IS_ERR(devctrl_regs)) 92 return PTR_ERR(devctrl_regs); 93 94 /* set soft/hard reset */ 95 val = of_property_read_bool(np, "ti,soft-reset"); 96 val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD; 97 98 ret = rsctrl_enable_rspll_write(); 99 if (ret) 100 return ret; 101 102 ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val); 103 if (ret) 104 return ret; 105 106 /* disable a reset isolation for all module clocks */ 107 ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0); 108 if (ret) 109 return ret; 110 111 /* enable a reset for watchdogs from wdt-list */ 112 for (i = 0; i < WDT_MUX_NUMBER; i++) { 113 ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val); 114 if (ret == -EOVERFLOW && !i) { 115 dev_err(dev, "ti,wdt-list property has to contain at" 116 "least one entry\n"); 117 return -EINVAL; 118 } else if (ret) { 119 break; 120 } 121 122 if (val >= WDT_MUX_NUMBER) { 123 dev_err(dev, "ti,wdt-list property can contain " 124 "only numbers < 4\n"); 125 return -EINVAL; 126 } 127 128 rg = rsmux_offset + val * 4; 129 130 ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK, 131 RSMUX_OMODE_RESET_ON | 132 RSMUX_LOCK_SET); 133 if (ret) 134 return ret; 135 } 136 137 ret = devm_register_sys_off_handler(dev, SYS_OFF_MODE_RESTART, 128, 138 rsctrl_restart_handler, NULL); 139 if (ret) 140 dev_err(dev, "cannot register restart handler (err=%d)\n", ret); 141 142 return ret; 143 } 144 145 static struct platform_driver rsctrl_driver = { 146 .probe = rsctrl_probe, 147 .driver = { 148 .name = KBUILD_MODNAME, 149 .of_match_table = rsctrl_of_match, 150 }, 151 }; 152 module_platform_driver(rsctrl_driver); 153 154 MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>"); 155 MODULE_DESCRIPTION("Texas Instruments keystone reset driver"); 156 MODULE_ALIAS("platform:" KBUILD_MODNAME); 157