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455 | giacomo | 1 | /* |
2 | * drivers/base/core.c - core driver model code (device registration, etc) |
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3 | * |
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4 | * Copyright (c) 2002-3 Patrick Mochel |
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5 | * Copyright (c) 2002-3 Open Source Development Labs |
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6 | * |
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7 | * This file is released under the GPLv2 |
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8 | * |
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9 | */ |
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10 | |||
11 | #undef DEBUG |
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12 | |||
13 | #include <linuxcomp.h> |
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14 | |||
15 | #include <linux/device.h> |
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16 | #include <linux/err.h> |
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17 | #include <linux/init.h> |
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18 | #include <linux/module.h> |
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19 | #include <linux/slab.h> |
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20 | #include <linux/string.h> |
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21 | |||
22 | #include <asm/semaphore.h> |
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23 | |||
24 | #include "base.h" |
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25 | |||
26 | int (*platform_notify)(struct device * dev) = NULL; |
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27 | int (*platform_notify_remove)(struct device * dev) = NULL; |
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28 | |||
29 | /* |
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30 | * sysfs bindings for devices. |
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31 | */ |
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32 | |||
33 | #define to_dev(obj) container_of(obj,struct device,kobj) |
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34 | #define to_dev_attr(_attr) container_of(_attr,struct device_attribute,attr) |
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35 | |||
36 | extern struct attribute * dev_default_attrs[]; |
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37 | |||
38 | static ssize_t |
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39 | dev_attr_show(struct kobject * kobj, struct attribute * attr, char * buf) |
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40 | { |
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41 | struct device_attribute * dev_attr = to_dev_attr(attr); |
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42 | struct device * dev = to_dev(kobj); |
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43 | ssize_t ret = 0; |
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44 | |||
45 | if (dev_attr->show) |
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46 | ret = dev_attr->show(dev,buf); |
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47 | return ret; |
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48 | } |
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49 | |||
50 | static ssize_t |
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51 | dev_attr_store(struct kobject * kobj, struct attribute * attr, |
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52 | const char * buf, size_t count) |
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53 | { |
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54 | struct device_attribute * dev_attr = to_dev_attr(attr); |
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55 | struct device * dev = to_dev(kobj); |
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56 | ssize_t ret = 0; |
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57 | |||
58 | if (dev_attr->store) |
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59 | ret = dev_attr->store(dev,buf,count); |
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60 | return ret; |
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61 | } |
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62 | |||
63 | static struct sysfs_ops dev_sysfs_ops = { |
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64 | .show = dev_attr_show, |
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65 | .store = dev_attr_store, |
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66 | }; |
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67 | |||
68 | |||
69 | /** |
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70 | * device_release - free device structure. |
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71 | * @kobj: device's kobject. |
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72 | * |
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73 | * This is called once the reference count for the object |
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74 | * reaches 0. We forward the call to the device's release |
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75 | * method, which should handle actually freeing the structure. |
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76 | */ |
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77 | static void device_release(struct kobject * kobj) |
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78 | { |
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79 | struct device * dev = to_dev(kobj); |
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80 | //struct completion * c = dev->complete; |
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81 | |||
82 | if (dev->release) |
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83 | dev->release(dev); |
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84 | else { |
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85 | printk(KERN_ERR "Device '%s' does not have a release() function, " |
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86 | "it is broken and must be fixed.\n", |
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87 | dev->bus_id); |
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88 | WARN_ON(1); |
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89 | } |
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90 | //if (c) |
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91 | // complete(c); |
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92 | } |
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93 | |||
94 | static struct kobj_type ktype_device = { |
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95 | .release = device_release, |
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96 | .sysfs_ops = &dev_sysfs_ops, |
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97 | .default_attrs = dev_default_attrs, |
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98 | }; |
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99 | |||
100 | |||
101 | static int dev_hotplug_filter(struct kset *kset, struct kobject *kobj) |
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102 | { |
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103 | struct kobj_type *ktype = get_ktype(kobj); |
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104 | |||
105 | if (ktype == &ktype_device) { |
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106 | struct device *dev = to_dev(kobj); |
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107 | if (dev->bus) |
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108 | return 1; |
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109 | } |
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110 | return 0; |
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111 | } |
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112 | |||
113 | static char *dev_hotplug_name(struct kset *kset, struct kobject *kobj) |
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114 | { |
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115 | struct device *dev = to_dev(kobj); |
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116 | |||
117 | return dev->bus->name; |
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118 | } |
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119 | |||
120 | static int dev_hotplug(struct kset *kset, struct kobject *kobj, char **envp, |
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121 | int num_envp, char *buffer, int buffer_size) |
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122 | { |
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123 | struct device *dev = to_dev(kobj); |
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124 | int retval = 0; |
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125 | |||
126 | if (dev->bus->hotplug) { |
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127 | /* have the bus specific function add its stuff */ |
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128 | retval = dev->bus->hotplug (dev, envp, num_envp, buffer, buffer_size); |
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129 | if (retval) { |
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130 | pr_debug ("%s - hotplug() returned %d\n", |
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131 | __FUNCTION__, retval); |
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132 | } |
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133 | } |
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134 | |||
135 | return retval; |
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136 | } |
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137 | |||
138 | static struct kset_hotplug_ops device_hotplug_ops = { |
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139 | .filter = dev_hotplug_filter, |
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140 | .name = dev_hotplug_name, |
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141 | .hotplug = dev_hotplug, |
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142 | }; |
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143 | |||
144 | /** |
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145 | * device_subsys - structure to be registered with kobject core. |
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146 | */ |
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147 | |||
148 | decl_subsys(devices, &ktype_device, &device_hotplug_ops); |
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149 | |||
150 | |||
151 | /** |
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152 | * device_create_file - create sysfs attribute file for device. |
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153 | * @dev: device. |
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154 | * @attr: device attribute descriptor. |
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155 | */ |
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156 | |||
157 | int device_create_file(struct device * dev, struct device_attribute * attr) |
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158 | { |
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159 | int error = 0; |
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160 | if (get_device(dev)) { |
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161 | error = 0;//sysfs_create_file(&dev->kobj,&attr->attr); |
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162 | put_device(dev); |
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163 | } |
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164 | return error; |
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165 | } |
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166 | |||
167 | /** |
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168 | * device_remove_file - remove sysfs attribute file. |
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169 | * @dev: device. |
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170 | * @attr: device attribute descriptor. |
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171 | */ |
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172 | |||
173 | void device_remove_file(struct device * dev, struct device_attribute * attr) |
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174 | { |
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175 | if (get_device(dev)) { |
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176 | //sysfs_remove_file(&dev->kobj,&attr->attr); |
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177 | put_device(dev); |
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178 | } |
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179 | } |
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180 | |||
181 | |||
182 | /** |
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183 | * device_initialize - init device structure. |
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184 | * @dev: device. |
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185 | * |
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186 | * This prepares the device for use by other layers, |
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187 | * including adding it to the device hierarchy. |
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188 | * It is the first half of device_register(), if called by |
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189 | * that, though it can also be called separately, so one |
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190 | * may use @dev's fields (e.g. the refcount). |
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191 | */ |
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192 | |||
193 | void device_initialize(struct device *dev) |
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194 | { |
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195 | kobj_set_kset_s(dev,devices_subsys); |
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196 | kobject_init(&dev->kobj); |
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197 | INIT_LIST_HEAD(&dev->node); |
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198 | INIT_LIST_HEAD(&dev->children); |
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199 | INIT_LIST_HEAD(&dev->driver_list); |
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200 | INIT_LIST_HEAD(&dev->bus_list); |
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201 | } |
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202 | |||
203 | /** |
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204 | * device_add - add device to device hierarchy. |
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205 | * @dev: device. |
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206 | * |
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207 | * This is part 2 of device_register(), though may be called |
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208 | * separately _iff_ device_initialize() has been called separately. |
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209 | * |
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210 | * This adds it to the kobject hierarchy via kobject_add(), adds it |
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211 | * to the global and sibling lists for the device, then |
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212 | * adds it to the other relevant subsystems of the driver model. |
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213 | */ |
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214 | int device_add(struct device *dev) |
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215 | { |
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216 | struct device * parent; |
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217 | int error; |
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218 | |||
219 | dev = get_device(dev); |
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220 | if (!dev || !strlen(dev->bus_id)) |
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221 | return -EINVAL; |
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222 | |||
223 | parent = get_device(dev->parent); |
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224 | |||
225 | pr_debug("DEV: registering device: ID = '%s'\n", dev->bus_id); |
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226 | |||
227 | /* first, register with generic layer. */ |
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228 | kobject_set_name(&dev->kobj,dev->bus_id); |
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229 | if (parent) |
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230 | dev->kobj.parent = &parent->kobj; |
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231 | |||
232 | if ((error = kobject_add(&dev->kobj))) |
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233 | goto Error; |
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234 | //if ((error = device_pm_add(dev))) |
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235 | // goto PMError; |
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236 | if ((error = bus_add_device(dev))) |
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237 | goto BusError; |
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238 | //down_write(&devices_subsys.rwsem); |
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239 | if (parent) |
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240 | list_add_tail(&dev->node,&parent->children); |
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241 | //up_write(&devices_subsys.rwsem); |
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242 | |||
243 | /* notify platform of device entry */ |
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244 | if (platform_notify) |
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245 | platform_notify(dev); |
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246 | Done: |
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247 | put_device(dev); |
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248 | return error; |
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249 | BusError: |
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250 | //device_pm_remove(dev); |
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251 | //PMError: |
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252 | kobject_unregister(&dev->kobj); |
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253 | Error: |
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254 | if (parent) |
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255 | put_device(parent); |
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256 | goto Done; |
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257 | } |
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258 | |||
259 | |||
260 | /** |
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261 | * device_register - register a device with the system. |
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262 | * @dev: pointer to the device structure |
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263 | * |
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264 | * This happens in two clean steps - initialize the device |
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265 | * and add it to the system. The two steps can be called |
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266 | * separately, but this is the easiest and most common. |
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267 | * I.e. you should only call the two helpers separately if |
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268 | * have a clearly defined need to use and refcount the device |
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269 | * before it is added to the hierarchy. |
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270 | */ |
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271 | |||
272 | int device_register(struct device *dev) |
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273 | { |
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274 | device_initialize(dev); |
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275 | return device_add(dev); |
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276 | } |
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277 | |||
278 | |||
279 | /** |
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280 | * get_device - increment reference count for device. |
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281 | * @dev: device. |
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282 | * |
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283 | * This simply forwards the call to kobject_get(), though |
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284 | * we do take care to provide for the case that we get a NULL |
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285 | * pointer passed in. |
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286 | */ |
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287 | |||
288 | struct device * get_device(struct device * dev) |
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289 | { |
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290 | return dev ? to_dev(kobject_get(&dev->kobj)) : NULL; |
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291 | } |
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292 | |||
293 | |||
294 | /** |
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295 | * put_device - decrement reference count. |
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296 | * @dev: device in question. |
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297 | */ |
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298 | void put_device(struct device * dev) |
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299 | { |
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300 | kobject_put(&dev->kobj); |
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301 | } |
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302 | |||
303 | |||
304 | /** |
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305 | * device_del - delete device from system. |
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306 | * @dev: device. |
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307 | * |
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308 | * This is the first part of the device unregistration |
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309 | * sequence. This removes the device from the lists we control |
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310 | * from here, has it removed from the other driver model |
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311 | * subsystems it was added to in device_add(), and removes it |
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312 | * from the kobject hierarchy. |
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313 | * |
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314 | * NOTE: this should be called manually _iff_ device_add() was |
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315 | * also called manually. |
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316 | */ |
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317 | |||
318 | void device_del(struct device * dev) |
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319 | { |
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320 | struct device * parent = dev->parent; |
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321 | |||
322 | //down_write(&devices_subsys.rwsem); |
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323 | if (parent) |
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324 | list_del_init(&dev->node); |
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325 | //up_write(&devices_subsys.rwsem); |
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326 | |||
327 | /* Notify the platform of the removal, in case they |
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328 | * need to do anything... |
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329 | */ |
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330 | if (platform_notify_remove) |
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331 | platform_notify_remove(dev); |
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332 | bus_remove_device(dev); |
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333 | //device_pm_remove(dev); |
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334 | kobject_del(&dev->kobj); |
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335 | if (parent) |
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336 | put_device(parent); |
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337 | } |
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338 | |||
339 | /** |
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340 | * device_unregister - unregister device from system. |
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341 | * @dev: device going away. |
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342 | * |
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343 | * We do this in two parts, like we do device_register(). First, |
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344 | * we remove it from all the subsystems with device_del(), then |
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345 | * we decrement the reference count via put_device(). If that |
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346 | * is the final reference count, the device will be cleaned up |
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347 | * via device_release() above. Otherwise, the structure will |
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348 | * stick around until the final reference to the device is dropped. |
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349 | */ |
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350 | void device_unregister(struct device * dev) |
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351 | { |
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352 | pr_debug("DEV: Unregistering device. ID = '%s'\n", dev->bus_id); |
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353 | device_del(dev); |
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354 | put_device(dev); |
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355 | } |
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356 | |||
357 | |||
358 | /** |
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359 | * device_unregister_wait - Unregister device and wait for it to be freed. |
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360 | * @dev: Device to unregister. |
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361 | * |
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362 | * For the cases where the caller needs to wait for all references to |
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363 | * be dropped from the device before continuing (e.g. modules with |
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364 | * statically allocated devices), this function uses a completion struct |
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365 | * to wait, along with a matching complete() in device_release() above. |
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366 | */ |
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367 | |||
368 | void device_unregister_wait(struct device * dev) |
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369 | { |
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370 | struct completion c; |
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371 | init_completion(&c); |
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372 | dev->complete = &c; |
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373 | device_unregister(dev); |
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374 | //wait_for_completion(&c); |
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375 | } |
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376 | |||
377 | /** |
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378 | * device_for_each_child - device child iterator. |
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379 | * @dev: parent struct device. |
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380 | * @data: data for the callback. |
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381 | * @fn: function to be called for each device. |
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382 | * |
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383 | * Iterate over @dev's child devices, and call @fn for each, |
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384 | * passing it @data. |
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385 | * |
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386 | * We check the return of @fn each time. If it returns anything |
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387 | * other than 0, we break out and return that value. |
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388 | */ |
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389 | int device_for_each_child(struct device * dev, void * data, |
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390 | int (*fn)(struct device *, void *)) |
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391 | { |
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392 | struct device * child; |
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393 | int error = 0; |
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394 | |||
395 | //down_read(&devices_subsys.rwsem); |
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396 | list_for_each_entry(child,&dev->children,node) { |
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397 | if((error = fn(child,data))) |
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398 | break; |
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399 | } |
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400 | //up_read(&devices_subsys.rwsem); |
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401 | return error; |
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402 | } |
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403 | |||
404 | int __init devices_init(void) |
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405 | { |
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406 | return subsystem_register(&devices_subsys); |
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407 | } |
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408 | |||
409 | EXPORT_SYMBOL(device_for_each_child); |
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410 | |||
411 | EXPORT_SYMBOL(device_initialize); |
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412 | EXPORT_SYMBOL(device_add); |
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413 | EXPORT_SYMBOL(device_register); |
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414 | |||
415 | EXPORT_SYMBOL(device_del); |
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416 | EXPORT_SYMBOL(device_unregister); |
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417 | EXPORT_SYMBOL(device_unregister_wait); |
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418 | EXPORT_SYMBOL(get_device); |
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419 | EXPORT_SYMBOL(put_device); |
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420 | |||
421 | EXPORT_SYMBOL(device_create_file); |
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422 | EXPORT_SYMBOL(device_remove_file); |