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 *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: 94 * * fpga_bridge struct pointer if successful. 95 * * -EBUSY if someone already has a reference to the bridge. 96 * * -ENODEV if @np is not an FPGA Bridge or can't take parent driver refcount. 97 */ 98 struct fpga_bridge *of_fpga_bridge_get(struct device_node *np, 99 struct fpga_image_info *info) 100 { 101 struct device *dev; 102 103 dev = class_find_device_by_of_node(&fpga_bridge_class, np); 104 if (!dev) 105 return ERR_PTR(-ENODEV); 106 107 return __fpga_bridge_get(dev, info); 108 } 109 EXPORT_SYMBOL_GPL(of_fpga_bridge_get); 110 111 static int fpga_bridge_dev_match(struct device *dev, const void *data) 112 { 113 return dev->parent == data; 114 } 115 116 /** 117 * fpga_bridge_get - get an exclusive reference to an fpga bridge 118 * @dev: parent device that fpga bridge was registered with 119 * @info: fpga image specific information 120 * 121 * Given a device, get an exclusive reference to an fpga bridge. 122 * 123 * Return: fpga bridge struct or IS_ERR() condition containing error code. 124 */ 125 struct fpga_bridge *fpga_bridge_get(struct device *dev, 126 struct fpga_image_info *info) 127 { 128 struct device *bridge_dev; 129 130 bridge_dev = class_find_device(&fpga_bridge_class, NULL, dev, 131 fpga_bridge_dev_match); 132 if (!bridge_dev) 133 return ERR_PTR(-ENODEV); 134 135 return __fpga_bridge_get(bridge_dev, info); 136 } 137 EXPORT_SYMBOL_GPL(fpga_bridge_get); 138 139 /** 140 * fpga_bridge_put - release a reference to a bridge 141 * 142 * @bridge: FPGA bridge 143 */ 144 void fpga_bridge_put(struct fpga_bridge *bridge) 145 { 146 dev_dbg(&bridge->dev, "put\n"); 147 148 bridge->info = NULL; 149 module_put(bridge->dev.parent->driver->owner); 150 mutex_unlock(&bridge->mutex); 151 put_device(&bridge->dev); 152 } 153 EXPORT_SYMBOL_GPL(fpga_bridge_put); 154 155 /** 156 * fpga_bridges_enable - enable bridges in a list 157 * @bridge_list: list of FPGA bridges 158 * 159 * Enable each bridge in the list. If list is empty, do nothing. 160 * 161 * Return: 0 for success or empty bridge list or an error code otherwise. 162 */ 163 int fpga_bridges_enable(struct list_head *bridge_list) 164 { 165 struct fpga_bridge *bridge; 166 int ret; 167 168 list_for_each_entry(bridge, bridge_list, node) { 169 ret = fpga_bridge_enable(bridge); 170 if (ret) 171 return ret; 172 } 173 174 return 0; 175 } 176 EXPORT_SYMBOL_GPL(fpga_bridges_enable); 177 178 /** 179 * fpga_bridges_disable - disable bridges in a list 180 * 181 * @bridge_list: list of FPGA bridges 182 * 183 * Disable each bridge in the list. If list is empty, do nothing. 184 * 185 * Return: 0 for success or empty bridge list or an error code otherwise. 186 */ 187 int fpga_bridges_disable(struct list_head *bridge_list) 188 { 189 struct fpga_bridge *bridge; 190 int ret; 191 192 list_for_each_entry(bridge, bridge_list, node) { 193 ret = fpga_bridge_disable(bridge); 194 if (ret) 195 return ret; 196 } 197 198 return 0; 199 } 200 EXPORT_SYMBOL_GPL(fpga_bridges_disable); 201 202 /** 203 * fpga_bridges_put - put bridges 204 * 205 * @bridge_list: list of FPGA bridges 206 * 207 * For each bridge in the list, put the bridge and remove it from the list. 208 * If list is empty, do nothing. 209 */ 210 void fpga_bridges_put(struct list_head *bridge_list) 211 { 212 struct fpga_bridge *bridge, *next; 213 unsigned long flags; 214 215 list_for_each_entry_safe(bridge, next, bridge_list, node) { 216 fpga_bridge_put(bridge); 217 218 spin_lock_irqsave(&bridge_list_lock, flags); 219 list_del(&bridge->node); 220 spin_unlock_irqrestore(&bridge_list_lock, flags); 221 } 222 } 223 EXPORT_SYMBOL_GPL(fpga_bridges_put); 224 225 /** 226 * of_fpga_bridge_get_to_list - get a bridge, add it to a list 227 * 228 * @np: node pointer of an FPGA bridge 229 * @info: fpga image specific information 230 * @bridge_list: list of FPGA bridges 231 * 232 * Get an exclusive reference to the bridge and it to the list. 233 * 234 * Return: 0 for success, error code from of_fpga_bridge_get() otherwise. 235 */ 236 int of_fpga_bridge_get_to_list(struct device_node *np, 237 struct fpga_image_info *info, 238 struct list_head *bridge_list) 239 { 240 struct fpga_bridge *bridge; 241 unsigned long flags; 242 243 bridge = of_fpga_bridge_get(np, info); 244 if (IS_ERR(bridge)) 245 return PTR_ERR(bridge); 246 247 spin_lock_irqsave(&bridge_list_lock, flags); 248 list_add(&bridge->node, bridge_list); 249 spin_unlock_irqrestore(&bridge_list_lock, flags); 250 251 return 0; 252 } 253 EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list); 254 255 /** 256 * fpga_bridge_get_to_list - given device, get a bridge, add it to a list 257 * 258 * @dev: FPGA bridge device 259 * @info: fpga image specific information 260 * @bridge_list: list of FPGA bridges 261 * 262 * Get an exclusive reference to the bridge and it to the list. 263 * 264 * Return: 0 for success, error code from fpga_bridge_get() otherwise. 265 */ 266 int fpga_bridge_get_to_list(struct device *dev, 267 struct fpga_image_info *info, 268 struct list_head *bridge_list) 269 { 270 struct fpga_bridge *bridge; 271 unsigned long flags; 272 273 bridge = fpga_bridge_get(dev, info); 274 if (IS_ERR(bridge)) 275 return PTR_ERR(bridge); 276 277 spin_lock_irqsave(&bridge_list_lock, flags); 278 list_add(&bridge->node, bridge_list); 279 spin_unlock_irqrestore(&bridge_list_lock, flags); 280 281 return 0; 282 } 283 EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list); 284 285 static ssize_t name_show(struct device *dev, 286 struct device_attribute *attr, char *buf) 287 { 288 struct fpga_bridge *bridge = to_fpga_bridge(dev); 289 290 return sprintf(buf, "%s\n", bridge->name); 291 } 292 293 static ssize_t state_show(struct device *dev, 294 struct device_attribute *attr, char *buf) 295 { 296 struct fpga_bridge *bridge = to_fpga_bridge(dev); 297 int state = 1; 298 299 if (bridge->br_ops->enable_show) { 300 state = bridge->br_ops->enable_show(bridge); 301 if (state < 0) 302 return state; 303 } 304 305 return sysfs_emit(buf, "%s\n", state ? "enabled" : "disabled"); 306 } 307 308 static DEVICE_ATTR_RO(name); 309 static DEVICE_ATTR_RO(state); 310 311 static struct attribute *fpga_bridge_attrs[] = { 312 &dev_attr_name.attr, 313 &dev_attr_state.attr, 314 NULL, 315 }; 316 ATTRIBUTE_GROUPS(fpga_bridge); 317 318 /** 319 * fpga_bridge_register - create and register an FPGA Bridge device 320 * @parent: FPGA bridge device from pdev 321 * @name: FPGA bridge name 322 * @br_ops: pointer to structure of fpga bridge ops 323 * @priv: FPGA bridge private data 324 * 325 * Return: struct fpga_bridge pointer or ERR_PTR() 326 */ 327 struct fpga_bridge * 328 fpga_bridge_register(struct device *parent, const char *name, 329 const struct fpga_bridge_ops *br_ops, 330 void *priv) 331 { 332 struct fpga_bridge *bridge; 333 int id, ret; 334 335 if (!br_ops) { 336 dev_err(parent, "Attempt to register without fpga_bridge_ops\n"); 337 return ERR_PTR(-EINVAL); 338 } 339 340 if (!name || !strlen(name)) { 341 dev_err(parent, "Attempt to register with no name!\n"); 342 return ERR_PTR(-EINVAL); 343 } 344 345 bridge = kzalloc(sizeof(*bridge), GFP_KERNEL); 346 if (!bridge) 347 return ERR_PTR(-ENOMEM); 348 349 id = ida_alloc(&fpga_bridge_ida, GFP_KERNEL); 350 if (id < 0) { 351 ret = id; 352 goto error_kfree; 353 } 354 355 mutex_init(&bridge->mutex); 356 INIT_LIST_HEAD(&bridge->node); 357 358 bridge->name = name; 359 bridge->br_ops = br_ops; 360 bridge->priv = priv; 361 362 bridge->dev.groups = br_ops->groups; 363 bridge->dev.class = &fpga_bridge_class; 364 bridge->dev.parent = parent; 365 bridge->dev.of_node = parent->of_node; 366 bridge->dev.id = id; 367 368 ret = dev_set_name(&bridge->dev, "br%d", id); 369 if (ret) 370 goto error_device; 371 372 ret = device_register(&bridge->dev); 373 if (ret) { 374 put_device(&bridge->dev); 375 return ERR_PTR(ret); 376 } 377 378 of_platform_populate(bridge->dev.of_node, NULL, NULL, &bridge->dev); 379 380 return bridge; 381 382 error_device: 383 ida_free(&fpga_bridge_ida, id); 384 error_kfree: 385 kfree(bridge); 386 387 return ERR_PTR(ret); 388 } 389 EXPORT_SYMBOL_GPL(fpga_bridge_register); 390 391 /** 392 * fpga_bridge_unregister - unregister an FPGA bridge 393 * 394 * @bridge: FPGA bridge struct 395 * 396 * This function is intended for use in an FPGA bridge driver's remove function. 397 */ 398 void fpga_bridge_unregister(struct fpga_bridge *bridge) 399 { 400 /* 401 * If the low level driver provides a method for putting bridge into 402 * a desired state upon unregister, do it. 403 */ 404 if (bridge->br_ops->fpga_bridge_remove) 405 bridge->br_ops->fpga_bridge_remove(bridge); 406 407 device_unregister(&bridge->dev); 408 } 409 EXPORT_SYMBOL_GPL(fpga_bridge_unregister); 410 411 static void fpga_bridge_dev_release(struct device *dev) 412 { 413 struct fpga_bridge *bridge = to_fpga_bridge(dev); 414 415 ida_free(&fpga_bridge_ida, bridge->dev.id); 416 kfree(bridge); 417 } 418 419 static const struct class fpga_bridge_class = { 420 .name = "fpga_bridge", 421 .dev_groups = fpga_bridge_groups, 422 .dev_release = fpga_bridge_dev_release, 423 }; 424 425 static int __init fpga_bridge_dev_init(void) 426 { 427 return class_register(&fpga_bridge_class); 428 } 429 430 static void __exit fpga_bridge_dev_exit(void) 431 { 432 class_unregister(&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