1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd 4 */ 5 6 #include <linux/device.h> 7 #include <linux/init.h> 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/of.h> 11 #include <linux/reboot.h> 12 #include <linux/reboot-mode.h> 13 14 #define PREFIX "mode-" 15 16 struct mode_info { 17 const char *mode; 18 u32 magic; 19 struct list_head list; 20 }; 21 22 static unsigned int get_reboot_mode_magic(struct reboot_mode_driver *reboot, 23 const char *cmd) 24 { 25 const char *normal = "normal"; 26 int magic = 0; 27 struct mode_info *info; 28 29 if (!cmd) 30 cmd = normal; 31 32 list_for_each_entry(info, &reboot->head, list) { 33 if (!strcmp(info->mode, cmd)) { 34 magic = info->magic; 35 break; 36 } 37 } 38 39 return magic; 40 } 41 42 static int reboot_mode_notify(struct notifier_block *this, 43 unsigned long mode, void *cmd) 44 { 45 struct reboot_mode_driver *reboot; 46 unsigned int magic; 47 48 reboot = container_of(this, struct reboot_mode_driver, reboot_notifier); 49 magic = get_reboot_mode_magic(reboot, cmd); 50 if (magic) 51 reboot->write(reboot, magic); 52 53 return NOTIFY_DONE; 54 } 55 56 /** 57 * reboot_mode_register - register a reboot mode driver 58 * @reboot: reboot mode driver 59 * 60 * Returns: 0 on success or a negative error code on failure. 61 */ 62 int reboot_mode_register(struct reboot_mode_driver *reboot) 63 { 64 struct mode_info *info; 65 struct property *prop; 66 struct device_node *np = reboot->dev->of_node; 67 size_t len = strlen(PREFIX); 68 int ret; 69 70 INIT_LIST_HEAD(&reboot->head); 71 72 for_each_property_of_node(np, prop) { 73 if (strncmp(prop->name, PREFIX, len)) 74 continue; 75 76 info = devm_kzalloc(reboot->dev, sizeof(*info), GFP_KERNEL); 77 if (!info) { 78 ret = -ENOMEM; 79 goto error; 80 } 81 82 if (of_property_read_u32(np, prop->name, &info->magic)) { 83 dev_err(reboot->dev, "reboot mode %s without magic number\n", 84 info->mode); 85 devm_kfree(reboot->dev, info); 86 continue; 87 } 88 89 info->mode = kstrdup_const(prop->name + len, GFP_KERNEL); 90 if (!info->mode) { 91 ret = -ENOMEM; 92 goto error; 93 } else if (info->mode[0] == '\0') { 94 kfree_const(info->mode); 95 ret = -EINVAL; 96 dev_err(reboot->dev, "invalid mode name(%s): too short!\n", 97 prop->name); 98 goto error; 99 } 100 101 list_add_tail(&info->list, &reboot->head); 102 } 103 104 reboot->reboot_notifier.notifier_call = reboot_mode_notify; 105 register_reboot_notifier(&reboot->reboot_notifier); 106 107 return 0; 108 109 error: 110 list_for_each_entry(info, &reboot->head, list) 111 kfree_const(info->mode); 112 113 return ret; 114 } 115 EXPORT_SYMBOL_GPL(reboot_mode_register); 116 117 /** 118 * reboot_mode_unregister - unregister a reboot mode driver 119 * @reboot: reboot mode driver 120 */ 121 int reboot_mode_unregister(struct reboot_mode_driver *reboot) 122 { 123 struct mode_info *info; 124 125 unregister_reboot_notifier(&reboot->reboot_notifier); 126 127 list_for_each_entry(info, &reboot->head, list) 128 kfree_const(info->mode); 129 130 return 0; 131 } 132 EXPORT_SYMBOL_GPL(reboot_mode_unregister); 133 134 static void devm_reboot_mode_release(struct device *dev, void *res) 135 { 136 reboot_mode_unregister(*(struct reboot_mode_driver **)res); 137 } 138 139 /** 140 * devm_reboot_mode_register() - resource managed reboot_mode_register() 141 * @dev: device to associate this resource with 142 * @reboot: reboot mode driver 143 * 144 * Returns: 0 on success or a negative error code on failure. 145 */ 146 int devm_reboot_mode_register(struct device *dev, 147 struct reboot_mode_driver *reboot) 148 { 149 struct reboot_mode_driver **dr; 150 int rc; 151 152 dr = devres_alloc(devm_reboot_mode_release, sizeof(*dr), GFP_KERNEL); 153 if (!dr) 154 return -ENOMEM; 155 156 rc = reboot_mode_register(reboot); 157 if (rc) { 158 devres_free(dr); 159 return rc; 160 } 161 162 *dr = reboot; 163 devres_add(dev, dr); 164 165 return 0; 166 } 167 EXPORT_SYMBOL_GPL(devm_reboot_mode_register); 168 169 static int devm_reboot_mode_match(struct device *dev, void *res, void *data) 170 { 171 struct reboot_mode_driver **p = res; 172 173 if (WARN_ON(!p || !*p)) 174 return 0; 175 176 return *p == data; 177 } 178 179 /** 180 * devm_reboot_mode_unregister() - resource managed reboot_mode_unregister() 181 * @dev: device to associate this resource with 182 * @reboot: reboot mode driver 183 */ 184 void devm_reboot_mode_unregister(struct device *dev, 185 struct reboot_mode_driver *reboot) 186 { 187 WARN_ON(devres_release(dev, 188 devm_reboot_mode_release, 189 devm_reboot_mode_match, reboot)); 190 } 191 EXPORT_SYMBOL_GPL(devm_reboot_mode_unregister); 192 193 MODULE_AUTHOR("Andy Yan <andy.yan@rock-chips.com"); 194 MODULE_DESCRIPTION("System reboot mode core library"); 195 MODULE_LICENSE("GPL v2"); 196