1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * FPGA Bridge Framework Driver 4 * 5 * Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved. 6 * Copyright (C) 2017 Intel Corporation 7 */ 8 #include <linux/fpga/fpga-bridge.h> 9 #include <linux/idr.h> 10 #include <linux/kernel.h> 11 #include <linux/module.h> 12 #include <linux/of_platform.h> 13 #include <linux/slab.h> 14 #include <linux/spinlock.h> 15 16 static DEFINE_IDA(fpga_bridge_ida); 17 static const struct class fpga_bridge_class; 18 19 /* Lock for adding/removing bridges to linked lists*/ 20 static DEFINE_SPINLOCK(bridge_list_lock); 21 22 /** 23 * fpga_bridge_enable - Enable transactions on the bridge 24 * 25 * @bridge: FPGA bridge 26 * 27 * Return: 0 for success, error code otherwise. 28 */ 29 int fpga_bridge_enable(struct fpga_bridge *bridge) 30 { 31 dev_dbg(&bridge->dev, "enable\n"); 32 33 if (bridge->br_ops->enable_set) 34 return bridge->br_ops->enable_set(bridge, 1); 35 36 return 0; 37 } 38 EXPORT_SYMBOL_GPL(fpga_bridge_enable); 39 40 /** 41 * fpga_bridge_disable - Disable transactions on the bridge 42 * 43 * @bridge: FPGA bridge 44 * 45 * Return: 0 for success, error code otherwise. 46 */ 47 int fpga_bridge_disable(struct fpga_bridge *bridge) 48 { 49 dev_dbg(&bridge->dev, "disable\n"); 50 51 if (bridge->br_ops->enable_set) 52 return bridge->br_ops->enable_set(bridge, 0); 53 54 return 0; 55 } 56 EXPORT_SYMBOL_GPL(fpga_bridge_disable); 57 58 static struct fpga_bridge *__fpga_bridge_get(struct device *bridge_dev, 59 struct fpga_image_info *info) 60 { 61 struct fpga_bridge *bridge; 62 63 bridge = to_fpga_bridge(bridge_dev); 64 65 bridge->info = info; 66 67 if (!mutex_trylock(&bridge->mutex)) 68 return ERR_PTR(-EBUSY); 69 70 if (!try_module_get(bridge->br_ops_owner)) { 71 mutex_unlock(&bridge->mutex); 72 return ERR_PTR(-ENODEV); 73 } 74 75 dev_dbg(&bridge->dev, "get\n"); 76 77 return bridge; 78 } 79 80 /** 81 * of_fpga_bridge_get - get an exclusive reference to an fpga bridge 82 * 83 * @np: node pointer of an FPGA bridge. 84 * @info: fpga image specific information. 85 * 86 * Return: 87 * * fpga_bridge struct pointer if successful. 88 * * -EBUSY if someone already has a reference to the bridge. 89 * * -ENODEV if @np is not an FPGA Bridge or can't take parent driver refcount. 90 */ 91 struct fpga_bridge *of_fpga_bridge_get(struct device_node *np, 92 struct fpga_image_info *info) 93 { 94 struct fpga_bridge *bridge; 95 struct device *bridge_dev; 96 97 bridge_dev = class_find_device_by_of_node(&fpga_bridge_class, np); 98 if (!bridge_dev) 99 return ERR_PTR(-ENODEV); 100 101 bridge = __fpga_bridge_get(bridge_dev, info); 102 if (IS_ERR(bridge)) 103 put_device(bridge_dev); 104 105 return bridge; 106 } 107 EXPORT_SYMBOL_GPL(of_fpga_bridge_get); 108 109 static int fpga_bridge_dev_match(struct device *dev, const void *data) 110 { 111 return dev->parent == data; 112 } 113 114 /** 115 * fpga_bridge_get - get an exclusive reference to an fpga bridge 116 * @dev: parent device that fpga bridge was registered with 117 * @info: fpga image specific information 118 * 119 * Given a device, get an exclusive reference to an fpga bridge. 120 * 121 * Return: fpga bridge struct or IS_ERR() condition containing error code. 122 */ 123 struct fpga_bridge *fpga_bridge_get(struct device *dev, 124 struct fpga_image_info *info) 125 { 126 struct fpga_bridge *bridge; 127 struct device *bridge_dev; 128 129 bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev, 130 fpga_bridge_dev_match); 131 if (!bridge_dev) 132 return ERR_PTR(-ENODEV); 133 134 bridge = __fpga_bridge_get(bridge_dev, info); 135 if (IS_ERR(bridge)) 136 put_device(bridge_dev); 137 138 return bridge; 139 } 140 EXPORT_SYMBOL_GPL(fpga_bridge_get); 141 142 /** 143 * fpga_bridge_put - release a reference to a bridge 144 * 145 * @bridge: FPGA bridge 146 */ 147 void fpga_bridge_put(struct fpga_bridge *bridge) 148 { 149 dev_dbg(&bridge->dev, "put\n"); 150 151 bridge->info = NULL; 152 module_put(bridge->br_ops_owner); 153 mutex_unlock(&bridge->mutex); 154 put_device(&bridge->dev); 155 } 156 EXPORT_SYMBOL_GPL(fpga_bridge_put); 157 158 /** 159 * fpga_bridges_enable - enable bridges in a list 160 * @bridge_list: list of FPGA bridges 161 * 162 * Enable each bridge in the list. If list is empty, do nothing. 163 * 164 * Return: 0 for success or empty bridge list or an error code otherwise. 165 */ 166 int fpga_bridges_enable(struct list_head *bridge_list) 167 { 168 struct fpga_bridge *bridge; 169 int ret; 170 171 list_for_each_entry(bridge, bridge_list, node) { 172 ret = fpga_bridge_enable(bridge); 173 if (ret) 174 return ret; 175 } 176 177 return 0; 178 } 179 EXPORT_SYMBOL_GPL(fpga_bridges_enable); 180 181 /** 182 * fpga_bridges_disable - disable bridges in a list 183 * 184 * @bridge_list: list of FPGA bridges 185 * 186 * Disable each bridge in the list. If list is empty, do nothing. 187 * 188 * Return: 0 for success or empty bridge list or an error code otherwise. 189 */ 190 int fpga_bridges_disable(struct list_head *bridge_list) 191 { 192 struct fpga_bridge *bridge; 193 int ret; 194 195 list_for_each_entry(bridge, bridge_list, node) { 196 ret = fpga_bridge_disable(bridge); 197 if (ret) 198 return ret; 199 } 200 201 return 0; 202 } 203 EXPORT_SYMBOL_GPL(fpga_bridges_disable); 204 205 /** 206 * fpga_bridges_put - put bridges 207 * 208 * @bridge_list: list of FPGA bridges 209 * 210 * For each bridge in the list, put the bridge and remove it from the list. 211 * If list is empty, do nothing. 212 */ 213 void fpga_bridges_put(struct list_head *bridge_list) 214 { 215 struct fpga_bridge *bridge, *next; 216 unsigned long flags; 217 218 list_for_each_entry_safe(bridge, next, bridge_list, node) { 219 fpga_bridge_put(bridge); 220 221 spin_lock_irqsave(&bridge_list_lock, flags); 222 list_del(&bridge->node); 223 spin_unlock_irqrestore(&bridge_list_lock, flags); 224 } 225 } 226 EXPORT_SYMBOL_GPL(fpga_bridges_put); 227 228 /** 229 * of_fpga_bridge_get_to_list - get a bridge, add it to a list 230 * 231 * @np: node pointer of an FPGA bridge 232 * @info: fpga image specific information 233 * @bridge_list: list of FPGA bridges 234 * 235 * Get an exclusive reference to the bridge and it to the list. 236 * 237 * Return: 0 for success, error code from of_fpga_bridge_get() otherwise. 238 */ 239 int of_fpga_bridge_get_to_list(struct device_node *np, 240 struct fpga_image_info *info, 241 struct list_head *bridge_list) 242 { 243 struct fpga_bridge *bridge; 244 unsigned long flags; 245 246 bridge = of_fpga_bridge_get(np, info); 247 if (IS_ERR(bridge)) 248 return PTR_ERR(bridge); 249 250 spin_lock_irqsave(&bridge_list_lock, flags); 251 list_add(&bridge->node, bridge_list); 252 spin_unlock_irqrestore(&bridge_list_lock, flags); 253 254 return 0; 255 } 256 EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list); 257 258 /** 259 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list 260 * 261 * @dev: FPGA bridge device 262 * @info: fpga image specific information 263 * @bridge_list: list of FPGA bridges 264 * 265 * Get an exclusive reference to the bridge and it to the list. 266 * 267 * Return: 0 for success, error code from fpga_bridge_get() otherwise. 268 */ 269 int fpga_bridge_get_to_list(struct device *dev, 270 struct fpga_image_info *info, 271 struct list_head *bridge_list) 272 { 273 struct fpga_bridge *bridge; 274 unsigned long flags; 275 276 bridge = fpga_bridge_get(dev, info); 277 if (IS_ERR(bridge)) 278 return PTR_ERR(bridge); 279 280 spin_lock_irqsave(&bridge_list_lock, flags); 281 list_add(&bridge->node, bridge_list); 282 spin_unlock_irqrestore(&bridge_list_lock, flags); 283 284 return 0; 285 } 286 EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list); 287 288 static ssize_t name_show(struct device *dev, 289 struct device_attribute *attr, char *buf) 290 { 291 struct fpga_bridge *bridge = to_fpga_bridge(dev); 292 293 return sprintf(buf, "%s\n", bridge->name); 294 } 295 296 static ssize_t state_show(struct device *dev, 297 struct device_attribute *attr, char *buf) 298 { 299 struct fpga_bridge *bridge = to_fpga_bridge(dev); 300 int state = 1; 301 302 if (bridge->br_ops->enable_show) { 303 state = bridge->br_ops->enable_show(bridge); 304 if (state < 0) 305 return state; 306 } 307 308 return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled"); 309 } 310 311 static DEVICE_ATTR_RO(name); 312 static DEVICE_ATTR_RO(state); 313 314 static struct attribute *fpga_bridge_attrs[] = { 315 &dev_attr_name.attr, 316 &dev_attr_state.attr, 317 NULL, 318 }; 319 ATTRIBUTE_GROUPS(fpga_bridge); 320 321 /** 322 * __fpga_bridge_register - create and register an FPGA Bridge device 323 * @parent: FPGA bridge device from pdev 324 * @name: FPGA bridge name 325 * @br_ops: pointer to structure of fpga bridge ops 326 * @priv: FPGA bridge private data 327 * @owner: owner module containing the br_ops 328 * 329 * Return: struct fpga_bridge pointer or ERR_PTR() 330 */ 331 struct fpga_bridge * 332 __fpga_bridge_register(struct device *parent, const char *name, 333 const struct fpga_bridge_ops *br_ops, 334 void *priv, struct module *owner) 335 { 336 struct fpga_bridge *bridge; 337 int id, ret; 338 339 if (!br_ops) { 340 dev_err(parent, "Attempt to register without fpga_bridge_ops\n"); 341 return ERR_PTR(-EINVAL); 342 } 343 344 if (!name || !strlen(name)) { 345 dev_err(parent, "Attempt to register with no name!\n"); 346 return ERR_PTR(-EINVAL); 347 } 348 349 bridge = kzalloc(sizeof(*bridge), GFP_KERNEL); 350 if (!bridge) 351 return ERR_PTR(-ENOMEM); 352 353 id = ida_alloc(&fpga_bridge_ida, GFP_KERNEL); 354 if (id < 0) { 355 ret = id; 356 goto error_kfree; 357 } 358 359 mutex_init(&bridge->mutex); 360 INIT_LIST_HEAD(&bridge->node); 361 362 bridge->name = name; 363 bridge->br_ops = br_ops; 364 bridge->br_ops_owner = owner; 365 bridge->priv = priv; 366 367 bridge->dev.groups = br_ops->groups; 368 bridge->dev.class = &fpga_bridge_class; 369 bridge->dev.parent = parent; 370 bridge->dev.of_node = parent->of_node; 371 bridge->dev.id = id; 372 373 ret = dev_set_name(&bridge->dev, "br%d", id); 374 if (ret) 375 goto error_device; 376 377 ret = device_register(&bridge->dev); 378 if (ret) { 379 put_device(&bridge->dev); 380 return ERR_PTR(ret); 381 } 382 383 of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev); 384 385 return bridge; 386 387 error_device: 388 ida_free(&fpga_bridge_ida, id); 389 error_kfree: 390 kfree(bridge); 391 392 return ERR_PTR(ret); 393 } 394 EXPORT_SYMBOL_GPL(__fpga_bridge_register); 395 396 /** 397 * fpga_bridge_unregister - unregister an FPGA bridge 398 * 399 * @bridge: FPGA bridge struct 400 * 401 * This function is intended for use in an FPGA bridge driver's remove function. 402 */ 403 void fpga_bridge_unregister(struct fpga_bridge *bridge) 404 { 405 /* 406 * If the low level driver provides a method for putting bridge into 407 * a desired state upon unregister, do it. 408 */ 409 if (bridge->br_ops->fpga_bridge_remove) 410 bridge->br_ops->fpga_bridge_remove(bridge); 411 412 device_unregister(&bridge->dev); 413 } 414 EXPORT_SYMBOL_GPL(fpga_bridge_unregister); 415 416 static void fpga_bridge_dev_release(struct device *dev) 417 { 418 struct fpga_bridge *bridge = to_fpga_bridge(dev); 419 420 ida_free(&fpga_bridge_ida, bridge->dev.id); 421 kfree(bridge); 422 } 423 424 static const struct class fpga_bridge_class = { 425 .name = "fpga_bridge", 426 .dev_groups = fpga_bridge_groups, 427 .dev_release = fpga_bridge_dev_release, 428 }; 429 430 static int __init fpga_bridge_dev_init(void) 431 { 432 return class_register(&fpga_bridge_class); 433 } 434 435 static void __exit fpga_bridge_dev_exit(void) 436 { 437 class_unregister(&fpga_bridge_class); 438 ida_destroy(&fpga_bridge_ida); 439 } 440 441 MODULE_DESCRIPTION("FPGA Bridge Driver"); 442 MODULE_AUTHOR("Alan Tull <atull@kernel.org>"); 443 MODULE_LICENSE("GPL v2"); 444 445 subsys_initcall(fpga_bridge_dev_init); 446 module_exit(fpga_bridge_dev_exit); 447