drivers/fpga/fpga-bridge.c

   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 spinlock_t bridge_list_lock;
  21
  22 static int fpga_bridge_of_node_match(struct device *dev, const void *data)
  23 {
  24         return dev->of_node == data;
  25 }
  26
  27 /**
  28  * fpga_bridge_enable - Enable transactions on the bridge
  29  *
  30  * @bridge: FPGA bridge
  31  *
  32  * Return: 0 for success, error code otherwise.
  33  */
  34 int fpga_bridge_enable(struct fpga_bridge *bridge)
  35 {
  36         dev_dbg(&bridge->dev, "enable\n");
  37
  38         if (bridge->br_ops && bridge->br_ops->enable_set)
  39                 return bridge->br_ops->enable_set(bridge, 1);
  40
  41         return 0;
  42 }
  43 EXPORT_SYMBOL_GPL(fpga_bridge_enable);
  44
  45 /**
  46  * fpga_bridge_disable - Disable transactions on the bridge
  47  *
  48  * @bridge: FPGA bridge
  49  *
  50  * Return: 0 for success, error code otherwise.
  51  */
  52 int fpga_bridge_disable(struct fpga_bridge *bridge)
  53 {
  54         dev_dbg(&bridge->dev, "disable\n");
  55
  56         if (bridge->br_ops && bridge->br_ops->enable_set)
  57                 return bridge->br_ops->enable_set(bridge, 0);
  58
  59         return 0;
  60 }
  61 EXPORT_SYMBOL_GPL(fpga_bridge_disable);
  62
  63 static struct fpga_bridge *__fpga_bridge_get(struct device *dev,
  64                                              struct fpga_image_info *info)
  65 {
  66         struct fpga_bridge *bridge;
  67         int ret = -ENODEV;
  68
  69         bridge = to_fpga_bridge(dev);
  70
  71         bridge->info = info;
  72
  73         if (!mutex_trylock(&bridge->mutex)) {
  74                 ret = -EBUSY;
  75                 goto err_dev;
  76         }
  77
  78         if (!try_module_get(dev->parent->driver->owner))
  79                 goto err_ll_mod;
  80
  81         dev_dbg(&bridge->dev, "get\n");
  82
  83         return bridge;
  84
  85 err_ll_mod:
  86         mutex_unlock(&bridge->mutex);
  87 err_dev:
  88         put_device(dev);
  89         return ERR_PTR(ret);
  90 }
  91
  92 /**
  93  * of_fpga_bridge_get - get an exclusive reference to a fpga bridge
  94  *
  95  * @np: node pointer of a FPGA bridge
  96  * @info: fpga image specific information
  97  *
  98  * Return fpga_bridge struct if successful.
  99  * Return -EBUSY if someone already has a reference to the bridge.
 100  * Return -ENODEV if @np is not a FPGA Bridge.
 101  */
 102 struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
 103                                        struct fpga_image_info *info)
 104 {
 105         struct device *dev;
 106
 107         dev = class_find_device(fpga_bridge_class, NULL, np,
 108                                 fpga_bridge_of_node_match);
 109         if (!dev)
 110                 return ERR_PTR(-ENODEV);
 111
 112         return __fpga_bridge_get(dev, info);
 113 }
 114 EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
 115
 116 static int fpga_bridge_dev_match(struct device *dev, const void *data)
 117 {
 118         return dev->parent == data;
 119 }
 120
 121 /**
 122  * fpga_bridge_get - get an exclusive reference to a fpga bridge
 123  * @dev:        parent device that fpga bridge was registered with
 124  * @info:       fpga manager info
 125  *
 126  * Given a device, get an exclusive reference to a fpga bridge.
 127  *
 128  * Return: fpga bridge struct or IS_ERR() condition containing error code.
 129  */
 130 struct fpga_bridge *fpga_bridge_get(struct device *dev,
 131                                     struct fpga_image_info *info)
 132 {
 133         struct device *bridge_dev;
 134
 135         bridge_dev = class_find_device(fpga_bridge_class, NULL, dev,
 136                                        fpga_bridge_dev_match);
 137         if (!bridge_dev)
 138                 return ERR_PTR(-ENODEV);
 139
 140         return __fpga_bridge_get(bridge_dev, info);
 141 }
 142 EXPORT_SYMBOL_GPL(fpga_bridge_get);
 143
 144 /**
 145  * fpga_bridge_put - release a reference to a bridge
 146  *
 147  * @bridge: FPGA bridge
 148  */
 149 void fpga_bridge_put(struct fpga_bridge *bridge)
 150 {
 151         dev_dbg(&bridge->dev, "put\n");
 152
 153         bridge->info = NULL;
 154         module_put(bridge->dev.parent->driver->owner);
 155         mutex_unlock(&bridge->mutex);
 156         put_device(&bridge->dev);
 157 }
 158 EXPORT_SYMBOL_GPL(fpga_bridge_put);
 159
 160 /**
 161  * fpga_bridges_enable - enable bridges in a list
 162  * @bridge_list: list of FPGA bridges
 163  *
 164  * Enable each bridge in the list.  If list is empty, do nothing.
 165  *
 166  * Return 0 for success or empty bridge list; return error code otherwise.
 167  */
 168 int fpga_bridges_enable(struct list_head *bridge_list)
 169 {
 170         struct fpga_bridge *bridge;
 171         int ret;
 172
 173         list_for_each_entry(bridge, bridge_list, node) {
 174                 ret = fpga_bridge_enable(bridge);
 175                 if (ret)
 176                         return ret;
 177         }
 178
 179         return 0;
 180 }
 181 EXPORT_SYMBOL_GPL(fpga_bridges_enable);
 182
 183 /**
 184  * fpga_bridges_disable - disable bridges in a list
 185  *
 186  * @bridge_list: list of FPGA bridges
 187  *
 188  * Disable each bridge in the list.  If list is empty, do nothing.
 189  *
 190  * Return 0 for success or empty bridge list; return error code otherwise.
 191  */
 192 int fpga_bridges_disable(struct list_head *bridge_list)
 193 {
 194         struct fpga_bridge *bridge;
 195         int ret;
 196
 197         list_for_each_entry(bridge, bridge_list, node) {
 198                 ret = fpga_bridge_disable(bridge);
 199                 if (ret)
 200                         return ret;
 201         }
 202
 203         return 0;
 204 }
 205 EXPORT_SYMBOL_GPL(fpga_bridges_disable);
 206
 207 /**
 208  * fpga_bridges_put - put bridges
 209  *
 210  * @bridge_list: list of FPGA bridges
 211  *
 212  * For each bridge in the list, put the bridge and remove it from the list.
 213  * If list is empty, do nothing.
 214  */
 215 void fpga_bridges_put(struct list_head *bridge_list)
 216 {
 217         struct fpga_bridge *bridge, *next;
 218         unsigned long flags;
 219
 220         list_for_each_entry_safe(bridge, next, bridge_list, node) {
 221                 fpga_bridge_put(bridge);
 222
 223                 spin_lock_irqsave(&bridge_list_lock, flags);
 224                 list_del(&bridge->node);
 225                 spin_unlock_irqrestore(&bridge_list_lock, flags);
 226         }
 227 }
 228 EXPORT_SYMBOL_GPL(fpga_bridges_put);
 229
 230 /**
 231  * of_fpga_bridge_get_to_list - get a bridge, add it to a list
 232  *
 233  * @np: node pointer of a FPGA bridge
 234  * @info: fpga image specific information
 235  * @bridge_list: list of FPGA bridges
 236  *
 237  * Get an exclusive reference to the bridge and and it to the list.
 238  *
 239  * Return 0 for success, error code from of_fpga_bridge_get() othewise.
 240  */
 241 int of_fpga_bridge_get_to_list(struct device_node *np,
 242                                struct fpga_image_info *info,
 243                                struct list_head *bridge_list)
 244 {
 245         struct fpga_bridge *bridge;
 246         unsigned long flags;
 247
 248         bridge = of_fpga_bridge_get(np, info);
 249         if (IS_ERR(bridge))
 250                 return PTR_ERR(bridge);
 251
 252         spin_lock_irqsave(&bridge_list_lock, flags);
 253         list_add(&bridge->node, bridge_list);
 254         spin_unlock_irqrestore(&bridge_list_lock, flags);
 255
 256         return 0;
 257 }
 258 EXPORT_SYMBOL_GPL(of_fpga_bridge_get_to_list);
 259
 260 /**
 261  * fpga_bridge_get_to_list - given device, get a bridge, add it to a list
 262  *
 263  * @dev: FPGA bridge device
 264  * @info: fpga image specific information
 265  * @bridge_list: list of FPGA bridges
 266  *
 267  * Get an exclusive reference to the bridge and and it to the list.
 268  *
 269  * Return 0 for success, error code from fpga_bridge_get() othewise.
 270  */
 271 int fpga_bridge_get_to_list(struct device *dev,
 272                             struct fpga_image_info *info,
 273                             struct list_head *bridge_list)
 274 {
 275         struct fpga_bridge *bridge;
 276         unsigned long flags;
 277
 278         bridge = fpga_bridge_get(dev, info);
 279         if (IS_ERR(bridge))
 280                 return PTR_ERR(bridge);
 281
 282         spin_lock_irqsave(&bridge_list_lock, flags);
 283         list_add(&bridge->node, bridge_list);
 284         spin_unlock_irqrestore(&bridge_list_lock, flags);
 285
 286         return 0;
 287 }
 288 EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
 289
 290 static ssize_t name_show(struct device *dev,
 291                          struct device_attribute *attr, char *buf)
 292 {
 293         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 294
 295         return sprintf(buf, "%s\n", bridge->name);
 296 }
 297
 298 static ssize_t state_show(struct device *dev,
 299                           struct device_attribute *attr, char *buf)
 300 {
 301         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 302         int enable = 1;
 303
 304         if (bridge->br_ops && bridge->br_ops->enable_show)
 305                 enable = bridge->br_ops->enable_show(bridge);
 306
 307         return sprintf(buf, "%s\n", enable ? "enabled" : "disabled");
 308 }
 309
 310 static DEVICE_ATTR_RO(name);
 311 static DEVICE_ATTR_RO(state);
 312
 313 static struct attribute *fpga_bridge_attrs[] = {
 314         &dev_attr_name.attr,
 315         &dev_attr_state.attr,
 316         NULL,
 317 };
 318 ATTRIBUTE_GROUPS(fpga_bridge);
 319
 320 /**
 321  * fpga_bridge_create - create and initialize a struct fpga_bridge
 322  * @dev:        FPGA bridge device from pdev
 323  * @name:       FPGA bridge name
 324  * @br_ops:     pointer to structure of fpga bridge ops
 325  * @priv:       FPGA bridge private data
 326  *
 327  * Return: struct fpga_bridge or NULL
 328  */
 329 struct fpga_bridge *fpga_bridge_create(struct device *dev, const char *name,
 330                                        const struct fpga_bridge_ops *br_ops,
 331                                        void *priv)
 332 {
 333         struct fpga_bridge *bridge;
 334         int id, ret = 0;
 335
 336         if (!name || !strlen(name)) {
 337                 dev_err(dev, "Attempt to register with no name!\n");
 338                 return NULL;
 339         }
 340
 341         bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
 342         if (!bridge)
 343                 return NULL;
 344
 345         id = ida_simple_get(&fpga_bridge_ida, 0, 0, GFP_KERNEL);
 346         if (id < 0) {
 347                 ret = id;
 348                 goto error_kfree;
 349         }
 350
 351         mutex_init(&bridge->mutex);
 352         INIT_LIST_HEAD(&bridge->node);
 353
 354         bridge->name = name;
 355         bridge->br_ops = br_ops;
 356         bridge->priv = priv;
 357
 358         device_initialize(&bridge->dev);
 359         bridge->dev.groups = br_ops->groups;
 360         bridge->dev.class = fpga_bridge_class;
 361         bridge->dev.parent = dev;
 362         bridge->dev.of_node = dev->of_node;
 363         bridge->dev.id = id;
 364
 365         ret = dev_set_name(&bridge->dev, "br%d", id);
 366         if (ret)
 367                 goto error_device;
 368
 369         return bridge;
 370
 371 error_device:
 372         ida_simple_remove(&fpga_bridge_ida, id);
 373 error_kfree:
 374         kfree(bridge);
 375
 376         return NULL;
 377 }
 378 EXPORT_SYMBOL_GPL(fpga_bridge_create);
 379
 380 /**
 381  * fpga_bridge_free - free a fpga bridge and its id
 382  * @bridge:     FPGA bridge struct created by fpga_bridge_create
 383  */
 384 void fpga_bridge_free(struct fpga_bridge *bridge)
 385 {
 386         ida_simple_remove(&fpga_bridge_ida, bridge->dev.id);
 387         kfree(bridge);
 388 }
 389 EXPORT_SYMBOL_GPL(fpga_bridge_free);
 390
 391 /**
 392  * fpga_bridge_register - register a fpga bridge
 393  * @bridge:     FPGA bridge struct created by fpga_bridge_create
 394  *
 395  * Return: 0 for success, error code otherwise.
 396  */
 397 int fpga_bridge_register(struct fpga_bridge *bridge)
 398 {
 399         struct device *dev = &bridge->dev;
 400         int ret;
 401
 402         ret = device_add(dev);
 403         if (ret)
 404                 return ret;
 405
 406         of_platform_populate(dev->of_node, NULL, NULL, dev);
 407
 408         dev_info(dev->parent, "fpga bridge [%s] registered\n", bridge->name);
 409
 410         return 0;
 411 }
 412 EXPORT_SYMBOL_GPL(fpga_bridge_register);
 413
 414 /**
 415  * fpga_bridge_unregister - unregister and free a fpga bridge
 416  * @bridge:     FPGA bridge struct created by fpga_bridge_create
 417  */
 418 void fpga_bridge_unregister(struct fpga_bridge *bridge)
 419 {
 420         /*
 421          * If the low level driver provides a method for putting bridge into
 422          * a desired state upon unregister, do it.
 423          */
 424         if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
 425                 bridge->br_ops->fpga_bridge_remove(bridge);
 426
 427         device_unregister(&bridge->dev);
 428 }
 429 EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
 430
 431 static void fpga_bridge_dev_release(struct device *dev)
 432 {
 433         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 434
 435         fpga_bridge_free(bridge);
 436 }
 437
 438 static int __init fpga_bridge_dev_init(void)
 439 {
 440         spin_lock_init(&bridge_list_lock);
 441
 442         fpga_bridge_class = class_create(THIS_MODULE, "fpga_bridge");
 443         if (IS_ERR(fpga_bridge_class))
 444                 return PTR_ERR(fpga_bridge_class);
 445
 446         fpga_bridge_class->dev_groups = fpga_bridge_groups;
 447         fpga_bridge_class->dev_release = fpga_bridge_dev_release;
 448
 449         return 0;
 450 }
 451
 452 static void __exit fpga_bridge_dev_exit(void)
 453 {
 454         class_destroy(fpga_bridge_class);
 455         ida_destroy(&fpga_bridge_ida);
 456 }
 457
 458 MODULE_DESCRIPTION("FPGA Bridge Driver");
 459 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
 460 MODULE_LICENSE("GPL v2");
 461
 462 subsys_initcall(fpga_bridge_dev_init);
 463 module_exit(fpga_bridge_dev_exit);