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