1 /* 2 * TI keystone reboot driver 3 * 4 * Copyright (C) 2014 Texas Instruments Incorporated. http://www.ti.com/ 5 * 6 * Author: Ivan Khoronzhuk <ivan.khoronzhuk@ti.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13 #include <linux/io.h> 14 #include <linux/module.h> 15 #include <linux/reboot.h> 16 #include <linux/regmap.h> 17 #include <asm/system_misc.h> 18 #include <linux/mfd/syscon.h> 19 #include <linux/of_platform.h> 20 21 #define RSTYPE_RG 0x0 22 #define RSCTRL_RG 0x4 23 #define RSCFG_RG 0x8 24 #define RSISO_RG 0xc 25 26 #define RSCTRL_KEY_MASK 0x0000ffff 27 #define RSCTRL_RESET_MASK BIT(16) 28 #define RSCTRL_KEY 0x5a69 29 30 #define RSMUX_OMODE_MASK 0xe 31 #define RSMUX_OMODE_RESET_ON 0xa 32 #define RSMUX_OMODE_RESET_OFF 0x0 33 #define RSMUX_LOCK_MASK 0x1 34 #define RSMUX_LOCK_SET 0x1 35 36 #define RSCFG_RSTYPE_SOFT 0x300f 37 #define RSCFG_RSTYPE_HARD 0x0 38 39 #define WDT_MUX_NUMBER 0x4 40 41 static int rspll_offset; 42 static struct regmap *pllctrl_regs; 43 44 /** 45 * rsctrl_enable_rspll_write - enable access to RSCTRL, RSCFG 46 * To be able to access to RSCTRL, RSCFG registers 47 * we have to write a key before 48 */ 49 static inline int rsctrl_enable_rspll_write(void) 50 { 51 return regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG, 52 RSCTRL_KEY_MASK, RSCTRL_KEY); 53 } 54 55 static void rsctrl_restart(enum reboot_mode mode, const char *cmd) 56 { 57 /* enable write access to RSTCTRL */ 58 rsctrl_enable_rspll_write(); 59 60 /* reset the SOC */ 61 regmap_update_bits(pllctrl_regs, rspll_offset + RSCTRL_RG, 62 RSCTRL_RESET_MASK, 0); 63 } 64 65 static struct of_device_id rsctrl_of_match[] = { 66 {.compatible = "ti,keystone-reset", }, 67 {}, 68 }; 69 70 static int rsctrl_probe(struct platform_device *pdev) 71 { 72 int i; 73 int ret; 74 u32 val; 75 unsigned int rg; 76 u32 rsmux_offset; 77 struct regmap *devctrl_regs; 78 struct device *dev = &pdev->dev; 79 struct device_node *np = dev->of_node; 80 81 if (!np) 82 return -ENODEV; 83 84 /* get regmaps */ 85 pllctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-pll"); 86 if (IS_ERR(pllctrl_regs)) 87 return PTR_ERR(pllctrl_regs); 88 89 devctrl_regs = syscon_regmap_lookup_by_phandle(np, "ti,syscon-dev"); 90 if (IS_ERR(devctrl_regs)) 91 return PTR_ERR(devctrl_regs); 92 93 ret = of_property_read_u32_index(np, "ti,syscon-pll", 1, &rspll_offset); 94 if (ret) { 95 dev_err(dev, "couldn't read the reset pll offset!\n"); 96 return -EINVAL; 97 } 98 99 ret = of_property_read_u32_index(np, "ti,syscon-dev", 1, &rsmux_offset); 100 if (ret) { 101 dev_err(dev, "couldn't read the rsmux offset!\n"); 102 return -EINVAL; 103 } 104 105 /* set soft/hard reset */ 106 val = of_property_read_bool(np, "ti,soft-reset"); 107 val = val ? RSCFG_RSTYPE_SOFT : RSCFG_RSTYPE_HARD; 108 109 ret = rsctrl_enable_rspll_write(); 110 if (ret) 111 return ret; 112 113 ret = regmap_write(pllctrl_regs, rspll_offset + RSCFG_RG, val); 114 if (ret) 115 return ret; 116 117 arm_pm_restart = rsctrl_restart; 118 119 /* disable a reset isolation for all module clocks */ 120 ret = regmap_write(pllctrl_regs, rspll_offset + RSISO_RG, 0); 121 if (ret) 122 return ret; 123 124 /* enable a reset for watchdogs from wdt-list */ 125 for (i = 0; i < WDT_MUX_NUMBER; i++) { 126 ret = of_property_read_u32_index(np, "ti,wdt-list", i, &val); 127 if (ret == -EOVERFLOW && !i) { 128 dev_err(dev, "ti,wdt-list property has to contain at" 129 "least one entry\n"); 130 return -EINVAL; 131 } else if (ret) { 132 break; 133 } 134 135 if (val >= WDT_MUX_NUMBER) { 136 dev_err(dev, "ti,wdt-list property can contain" 137 "only numbers < 4\n"); 138 return -EINVAL; 139 } 140 141 rg = rsmux_offset + val * 4; 142 143 ret = regmap_update_bits(devctrl_regs, rg, RSMUX_OMODE_MASK, 144 RSMUX_OMODE_RESET_ON | 145 RSMUX_LOCK_SET); 146 if (ret) 147 return ret; 148 } 149 150 return 0; 151 } 152 153 static struct platform_driver rsctrl_driver = { 154 .probe = rsctrl_probe, 155 .driver = { 156 .owner = THIS_MODULE, 157 .name = KBUILD_MODNAME, 158 .of_match_table = rsctrl_of_match, 159 }, 160 }; 161 module_platform_driver(rsctrl_driver); 162 163 MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>"); 164 MODULE_DESCRIPTION("Texas Instruments keystone reset driver"); 165 MODULE_LICENSE("GPL v2"); 166 MODULE_ALIAS("platform:" KBUILD_MODNAME); 167