Russell King | 2a41e60 | 2014-01-10 23:23:37 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Componentized device handling. |
| 3 | * |
| 4 | * This program is free software; you can redistribute it and/or modify |
| 5 | * it under the terms of the GNU General Public License version 2 as |
| 6 | * published by the Free Software Foundation. |
| 7 | * |
| 8 | * This is work in progress. We gather up the component devices into a list, |
| 9 | * and bind them when instructed. At the moment, we're specific to the DRM |
| 10 | * subsystem, and only handles one master device, but this doesn't have to be |
| 11 | * the case. |
| 12 | */ |
| 13 | #include <linux/component.h> |
| 14 | #include <linux/device.h> |
| 15 | #include <linux/kref.h> |
| 16 | #include <linux/list.h> |
| 17 | #include <linux/module.h> |
| 18 | #include <linux/mutex.h> |
| 19 | #include <linux/slab.h> |
| 20 | |
| 21 | struct master { |
| 22 | struct list_head node; |
| 23 | struct list_head components; |
| 24 | bool bound; |
| 25 | |
| 26 | const struct component_master_ops *ops; |
| 27 | struct device *dev; |
| 28 | }; |
| 29 | |
| 30 | struct component { |
| 31 | struct list_head node; |
| 32 | struct list_head master_node; |
| 33 | struct master *master; |
| 34 | bool bound; |
| 35 | |
| 36 | const struct component_ops *ops; |
| 37 | struct device *dev; |
| 38 | }; |
| 39 | |
| 40 | static DEFINE_MUTEX(component_mutex); |
| 41 | static LIST_HEAD(component_list); |
| 42 | static LIST_HEAD(masters); |
| 43 | |
| 44 | static struct master *__master_find(struct device *dev, |
| 45 | const struct component_master_ops *ops) |
| 46 | { |
| 47 | struct master *m; |
| 48 | |
| 49 | list_for_each_entry(m, &masters, node) |
| 50 | if (m->dev == dev && (!ops || m->ops == ops)) |
| 51 | return m; |
| 52 | |
| 53 | return NULL; |
| 54 | } |
| 55 | |
| 56 | /* Attach an unattached component to a master. */ |
| 57 | static void component_attach_master(struct master *master, struct component *c) |
| 58 | { |
| 59 | c->master = master; |
| 60 | |
| 61 | list_add_tail(&c->master_node, &master->components); |
| 62 | } |
| 63 | |
| 64 | /* Detach a component from a master. */ |
| 65 | static void component_detach_master(struct master *master, struct component *c) |
| 66 | { |
| 67 | list_del(&c->master_node); |
| 68 | |
| 69 | c->master = NULL; |
| 70 | } |
| 71 | |
| 72 | int component_master_add_child(struct master *master, |
| 73 | int (*compare)(struct device *, void *), void *compare_data) |
| 74 | { |
| 75 | struct component *c; |
| 76 | int ret = -ENXIO; |
| 77 | |
| 78 | list_for_each_entry(c, &component_list, node) { |
| 79 | if (c->master) |
| 80 | continue; |
| 81 | |
| 82 | if (compare(c->dev, compare_data)) { |
| 83 | component_attach_master(master, c); |
| 84 | ret = 0; |
| 85 | break; |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | return ret; |
| 90 | } |
| 91 | EXPORT_SYMBOL_GPL(component_master_add_child); |
| 92 | |
| 93 | /* Detach all attached components from this master */ |
| 94 | static void master_remove_components(struct master *master) |
| 95 | { |
| 96 | while (!list_empty(&master->components)) { |
| 97 | struct component *c = list_first_entry(&master->components, |
| 98 | struct component, master_node); |
| 99 | |
| 100 | WARN_ON(c->master != master); |
| 101 | |
| 102 | component_detach_master(master, c); |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | /* |
| 107 | * Try to bring up a master. If component is NULL, we're interested in |
| 108 | * this master, otherwise it's a component which must be present to try |
| 109 | * and bring up the master. |
| 110 | * |
| 111 | * Returns 1 for successful bringup, 0 if not ready, or -ve errno. |
| 112 | */ |
| 113 | static int try_to_bring_up_master(struct master *master, |
| 114 | struct component *component) |
| 115 | { |
| 116 | int ret = 0; |
| 117 | |
| 118 | if (!master->bound) { |
| 119 | /* |
| 120 | * Search the list of components, looking for components that |
| 121 | * belong to this master, and attach them to the master. |
| 122 | */ |
| 123 | if (master->ops->add_components(master->dev, master)) { |
| 124 | /* Failed to find all components */ |
| 125 | master_remove_components(master); |
| 126 | ret = 0; |
| 127 | goto out; |
| 128 | } |
| 129 | |
| 130 | if (component && component->master != master) { |
| 131 | master_remove_components(master); |
| 132 | ret = 0; |
| 133 | goto out; |
| 134 | } |
| 135 | |
Russell King | 9e1ccb4 | 2014-02-07 20:09:27 +0000 | [diff] [blame] | 136 | if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) { |
| 137 | ret = -ENOMEM; |
| 138 | goto out; |
| 139 | } |
| 140 | |
Russell King | 2a41e60 | 2014-01-10 23:23:37 +0000 | [diff] [blame] | 141 | /* Found all components */ |
| 142 | ret = master->ops->bind(master->dev); |
| 143 | if (ret < 0) { |
Russell King | 9e1ccb4 | 2014-02-07 20:09:27 +0000 | [diff] [blame] | 144 | devres_release_group(master->dev, NULL); |
| 145 | dev_info(master->dev, "master bind failed: %d\n", ret); |
Russell King | 2a41e60 | 2014-01-10 23:23:37 +0000 | [diff] [blame] | 146 | master_remove_components(master); |
| 147 | goto out; |
| 148 | } |
| 149 | |
| 150 | master->bound = true; |
| 151 | ret = 1; |
| 152 | } |
| 153 | out: |
| 154 | |
| 155 | return ret; |
| 156 | } |
| 157 | |
| 158 | static int try_to_bring_up_masters(struct component *component) |
| 159 | { |
| 160 | struct master *m; |
| 161 | int ret = 0; |
| 162 | |
| 163 | list_for_each_entry(m, &masters, node) { |
| 164 | ret = try_to_bring_up_master(m, component); |
| 165 | if (ret != 0) |
| 166 | break; |
| 167 | } |
| 168 | |
| 169 | return ret; |
| 170 | } |
| 171 | |
| 172 | static void take_down_master(struct master *master) |
| 173 | { |
| 174 | if (master->bound) { |
| 175 | master->ops->unbind(master->dev); |
Russell King | 9e1ccb4 | 2014-02-07 20:09:27 +0000 | [diff] [blame] | 176 | devres_release_group(master->dev, NULL); |
Russell King | 2a41e60 | 2014-01-10 23:23:37 +0000 | [diff] [blame] | 177 | master->bound = false; |
| 178 | } |
| 179 | |
| 180 | master_remove_components(master); |
| 181 | } |
| 182 | |
| 183 | int component_master_add(struct device *dev, |
| 184 | const struct component_master_ops *ops) |
| 185 | { |
| 186 | struct master *master; |
| 187 | int ret; |
| 188 | |
| 189 | master = kzalloc(sizeof(*master), GFP_KERNEL); |
| 190 | if (!master) |
| 191 | return -ENOMEM; |
| 192 | |
| 193 | master->dev = dev; |
| 194 | master->ops = ops; |
| 195 | INIT_LIST_HEAD(&master->components); |
| 196 | |
| 197 | /* Add to the list of available masters. */ |
| 198 | mutex_lock(&component_mutex); |
| 199 | list_add(&master->node, &masters); |
| 200 | |
| 201 | ret = try_to_bring_up_master(master, NULL); |
| 202 | |
| 203 | if (ret < 0) { |
| 204 | /* Delete off the list if we weren't successful */ |
| 205 | list_del(&master->node); |
| 206 | kfree(master); |
| 207 | } |
| 208 | mutex_unlock(&component_mutex); |
| 209 | |
| 210 | return ret < 0 ? ret : 0; |
| 211 | } |
| 212 | EXPORT_SYMBOL_GPL(component_master_add); |
| 213 | |
| 214 | void component_master_del(struct device *dev, |
| 215 | const struct component_master_ops *ops) |
| 216 | { |
| 217 | struct master *master; |
| 218 | |
| 219 | mutex_lock(&component_mutex); |
| 220 | master = __master_find(dev, ops); |
| 221 | if (master) { |
| 222 | take_down_master(master); |
| 223 | |
| 224 | list_del(&master->node); |
| 225 | kfree(master); |
| 226 | } |
| 227 | mutex_unlock(&component_mutex); |
| 228 | } |
| 229 | EXPORT_SYMBOL_GPL(component_master_del); |
| 230 | |
| 231 | static void component_unbind(struct component *component, |
| 232 | struct master *master, void *data) |
| 233 | { |
| 234 | WARN_ON(!component->bound); |
| 235 | |
| 236 | component->ops->unbind(component->dev, master->dev, data); |
| 237 | component->bound = false; |
| 238 | |
| 239 | /* Release all resources claimed in the binding of this component */ |
| 240 | devres_release_group(component->dev, component); |
| 241 | } |
| 242 | |
| 243 | void component_unbind_all(struct device *master_dev, void *data) |
| 244 | { |
| 245 | struct master *master; |
| 246 | struct component *c; |
| 247 | |
| 248 | WARN_ON(!mutex_is_locked(&component_mutex)); |
| 249 | |
| 250 | master = __master_find(master_dev, NULL); |
| 251 | if (!master) |
| 252 | return; |
| 253 | |
| 254 | list_for_each_entry_reverse(c, &master->components, master_node) |
| 255 | component_unbind(c, master, data); |
| 256 | } |
| 257 | EXPORT_SYMBOL_GPL(component_unbind_all); |
| 258 | |
| 259 | static int component_bind(struct component *component, struct master *master, |
| 260 | void *data) |
| 261 | { |
| 262 | int ret; |
| 263 | |
| 264 | /* |
| 265 | * Each component initialises inside its own devres group. |
| 266 | * This allows us to roll-back a failed component without |
| 267 | * affecting anything else. |
| 268 | */ |
| 269 | if (!devres_open_group(master->dev, NULL, GFP_KERNEL)) |
| 270 | return -ENOMEM; |
| 271 | |
| 272 | /* |
| 273 | * Also open a group for the device itself: this allows us |
| 274 | * to release the resources claimed against the sub-device |
| 275 | * at the appropriate moment. |
| 276 | */ |
| 277 | if (!devres_open_group(component->dev, component, GFP_KERNEL)) { |
| 278 | devres_release_group(master->dev, NULL); |
| 279 | return -ENOMEM; |
| 280 | } |
| 281 | |
| 282 | dev_dbg(master->dev, "binding %s (ops %ps)\n", |
| 283 | dev_name(component->dev), component->ops); |
| 284 | |
| 285 | ret = component->ops->bind(component->dev, master->dev, data); |
| 286 | if (!ret) { |
| 287 | component->bound = true; |
| 288 | |
| 289 | /* |
| 290 | * Close the component device's group so that resources |
| 291 | * allocated in the binding are encapsulated for removal |
| 292 | * at unbind. Remove the group on the DRM device as we |
| 293 | * can clean those resources up independently. |
| 294 | */ |
| 295 | devres_close_group(component->dev, NULL); |
| 296 | devres_remove_group(master->dev, NULL); |
| 297 | |
| 298 | dev_info(master->dev, "bound %s (ops %ps)\n", |
| 299 | dev_name(component->dev), component->ops); |
| 300 | } else { |
| 301 | devres_release_group(component->dev, NULL); |
| 302 | devres_release_group(master->dev, NULL); |
| 303 | |
| 304 | dev_err(master->dev, "failed to bind %s (ops %ps): %d\n", |
| 305 | dev_name(component->dev), component->ops, ret); |
| 306 | } |
| 307 | |
| 308 | return ret; |
| 309 | } |
| 310 | |
| 311 | int component_bind_all(struct device *master_dev, void *data) |
| 312 | { |
| 313 | struct master *master; |
| 314 | struct component *c; |
| 315 | int ret = 0; |
| 316 | |
| 317 | WARN_ON(!mutex_is_locked(&component_mutex)); |
| 318 | |
| 319 | master = __master_find(master_dev, NULL); |
| 320 | if (!master) |
| 321 | return -EINVAL; |
| 322 | |
| 323 | list_for_each_entry(c, &master->components, master_node) { |
| 324 | ret = component_bind(c, master, data); |
| 325 | if (ret) |
| 326 | break; |
| 327 | } |
| 328 | |
| 329 | if (ret != 0) { |
| 330 | list_for_each_entry_continue_reverse(c, &master->components, |
| 331 | master_node) |
| 332 | component_unbind(c, master, data); |
| 333 | } |
| 334 | |
| 335 | return ret; |
| 336 | } |
| 337 | EXPORT_SYMBOL_GPL(component_bind_all); |
| 338 | |
| 339 | int component_add(struct device *dev, const struct component_ops *ops) |
| 340 | { |
| 341 | struct component *component; |
| 342 | int ret; |
| 343 | |
| 344 | component = kzalloc(sizeof(*component), GFP_KERNEL); |
| 345 | if (!component) |
| 346 | return -ENOMEM; |
| 347 | |
| 348 | component->ops = ops; |
| 349 | component->dev = dev; |
| 350 | |
| 351 | dev_dbg(dev, "adding component (ops %ps)\n", ops); |
| 352 | |
| 353 | mutex_lock(&component_mutex); |
| 354 | list_add_tail(&component->node, &component_list); |
| 355 | |
| 356 | ret = try_to_bring_up_masters(component); |
| 357 | if (ret < 0) { |
| 358 | list_del(&component->node); |
| 359 | |
| 360 | kfree(component); |
| 361 | } |
| 362 | mutex_unlock(&component_mutex); |
| 363 | |
| 364 | return ret < 0 ? ret : 0; |
| 365 | } |
| 366 | EXPORT_SYMBOL_GPL(component_add); |
| 367 | |
| 368 | void component_del(struct device *dev, const struct component_ops *ops) |
| 369 | { |
| 370 | struct component *c, *component = NULL; |
| 371 | |
| 372 | mutex_lock(&component_mutex); |
| 373 | list_for_each_entry(c, &component_list, node) |
| 374 | if (c->dev == dev && c->ops == ops) { |
| 375 | list_del(&c->node); |
| 376 | component = c; |
| 377 | break; |
| 378 | } |
| 379 | |
| 380 | if (component && component->master) |
| 381 | take_down_master(component->master); |
| 382 | |
| 383 | mutex_unlock(&component_mutex); |
| 384 | |
| 385 | WARN_ON(!component); |
| 386 | kfree(component); |
| 387 | } |
| 388 | EXPORT_SYMBOL_GPL(component_del); |
| 389 | |
| 390 | MODULE_LICENSE("GPL v2"); |