drivers/fpga/fpga-bridge.c

   1 /*
   2  * FPGA Bridge Framework Driver
   3  *
   4  *  Copyright (C) 2013-2016 Altera Corporation, All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13  * more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along with
  16  * this program.  If not, see <http://www.gnu.org/licenses/>.
  17  */
  18 #include <linux/fpga/fpga-bridge.h>
  19 #include <linux/idr.h>
  20 #include <linux/kernel.h>
  21 #include <linux/module.h>
  22 #include <linux/of_platform.h>
  23 #include <linux/slab.h>
  24 #include <linux/spinlock.h>
  25
  26 static DEFINE_IDA(fpga_bridge_ida);
  27 static struct class *fpga_bridge_class;
  28
  29 /* Lock for adding/removing bridges to linked lists*/
  30 spinlock_t bridge_list_lock;
  31
  32 static int fpga_bridge_of_node_match(struct device *dev, const void *data)
  33 {
  34         return dev->of_node == data;
  35 }
  36
  37 /**
  38  * fpga_bridge_enable - Enable transactions on the bridge
  39  *
  40  * @bridge: FPGA bridge
  41  *
  42  * Return: 0 for success, error code otherwise.
  43  */
  44 int fpga_bridge_enable(struct fpga_bridge *bridge)
  45 {
  46         dev_dbg(&bridge->dev, "enable\n");
  47
  48         if (bridge->br_ops && bridge->br_ops->enable_set)
  49                 return bridge->br_ops->enable_set(bridge, 1);
  50
  51         return 0;
  52 }
  53 EXPORT_SYMBOL_GPL(fpga_bridge_enable);
  54
  55 /**
  56  * fpga_bridge_disable - Disable transactions on the bridge
  57  *
  58  * @bridge: FPGA bridge
  59  *
  60  * Return: 0 for success, error code otherwise.
  61  */
  62 int fpga_bridge_disable(struct fpga_bridge *bridge)
  63 {
  64         dev_dbg(&bridge->dev, "disable\n");
  65
  66         if (bridge->br_ops && bridge->br_ops->enable_set)
  67                 return bridge->br_ops->enable_set(bridge, 0);
  68
  69         return 0;
  70 }
  71 EXPORT_SYMBOL_GPL(fpga_bridge_disable);
  72
  73 /**
  74  * of_fpga_bridge_get - get an exclusive reference to a fpga bridge
  75  *
  76  * @np: node pointer of a FPGA bridge
  77  * @info: fpga image specific information
  78  *
  79  * Return fpga_bridge struct if successful.
  80  * Return -EBUSY if someone already has a reference to the bridge.
  81  * Return -ENODEV if @np is not a FPGA Bridge.
  82  */
  83 struct fpga_bridge *of_fpga_bridge_get(struct device_node *np,
  84                                        struct fpga_image_info *info)
  85
  86 {
  87         struct device *dev;
  88         struct fpga_bridge *bridge;
  89         int ret = -ENODEV;
  90
  91         dev = class_find_device(fpga_bridge_class, NULL, np,
  92                                 fpga_bridge_of_node_match);
  93         if (!dev)
  94                 goto err_dev;
  95
  96         bridge = to_fpga_bridge(dev);
  97         if (!bridge)
  98                 goto err_dev;
  99
 100         bridge->info = info;
 101
 102         if (!mutex_trylock(&bridge->mutex)) {
 103                 ret = -EBUSY;
 104                 goto err_dev;
 105         }
 106
 107         if (!try_module_get(dev->parent->driver->owner))
 108                 goto err_ll_mod;
 109
 110         dev_dbg(&bridge->dev, "get\n");
 111
 112         return bridge;
 113
 114 err_ll_mod:
 115         mutex_unlock(&bridge->mutex);
 116 err_dev:
 117         put_device(dev);
 118         return ERR_PTR(ret);
 119 }
 120 EXPORT_SYMBOL_GPL(of_fpga_bridge_get);
 121
 122 /**
 123  * fpga_bridge_put - release a reference to a bridge
 124  *
 125  * @bridge: FPGA bridge
 126  */
 127 void fpga_bridge_put(struct fpga_bridge *bridge)
 128 {
 129         dev_dbg(&bridge->dev, "put\n");
 130
 131         bridge->info = NULL;
 132         module_put(bridge->dev.parent->driver->owner);
 133         mutex_unlock(&bridge->mutex);
 134         put_device(&bridge->dev);
 135 }
 136 EXPORT_SYMBOL_GPL(fpga_bridge_put);
 137
 138 /**
 139  * fpga_bridges_enable - enable bridges in a list
 140  * @bridge_list: list of FPGA bridges
 141  *
 142  * Enable each bridge in the list.  If list is empty, do nothing.
 143  *
 144  * Return 0 for success or empty bridge list; return error code otherwise.
 145  */
 146 int fpga_bridges_enable(struct list_head *bridge_list)
 147 {
 148         struct fpga_bridge *bridge;
 149         struct list_head *node;
 150         int ret;
 151
 152         list_for_each(node, bridge_list) {
 153                 bridge = list_entry(node, struct fpga_bridge, node);
 154                 ret = fpga_bridge_enable(bridge);
 155                 if (ret)
 156                         return ret;
 157         }
 158
 159         return 0;
 160 }
 161 EXPORT_SYMBOL_GPL(fpga_bridges_enable);
 162
 163 /**
 164  * fpga_bridges_disable - disable bridges in a list
 165  *
 166  * @bridge_list: list of FPGA bridges
 167  *
 168  * Disable each bridge in the list.  If list is empty, do nothing.
 169  *
 170  * Return 0 for success or empty bridge list; return error code otherwise.
 171  */
 172 int fpga_bridges_disable(struct list_head *bridge_list)
 173 {
 174         struct fpga_bridge *bridge;
 175         struct list_head *node;
 176         int ret;
 177
 178         list_for_each(node, bridge_list) {
 179                 bridge = list_entry(node, struct fpga_bridge, node);
 180                 ret = fpga_bridge_disable(bridge);
 181                 if (ret)
 182                         return ret;
 183         }
 184
 185         return 0;
 186 }
 187 EXPORT_SYMBOL_GPL(fpga_bridges_disable);
 188
 189 /**
 190  * fpga_bridges_put - put bridges
 191  *
 192  * @bridge_list: list of FPGA bridges
 193  *
 194  * For each bridge in the list, put the bridge and remove it from the list.
 195  * If list is empty, do nothing.
 196  */
 197 void fpga_bridges_put(struct list_head *bridge_list)
 198 {
 199         struct fpga_bridge *bridge;
 200         struct list_head *node, *next;
 201         unsigned long flags;
 202
 203         list_for_each_safe(node, next, bridge_list) {
 204                 bridge = list_entry(node, struct fpga_bridge, node);
 205
 206                 fpga_bridge_put(bridge);
 207
 208                 spin_lock_irqsave(&bridge_list_lock, flags);
 209                 list_del(&bridge->node);
 210                 spin_unlock_irqrestore(&bridge_list_lock, flags);
 211         }
 212 }
 213 EXPORT_SYMBOL_GPL(fpga_bridges_put);
 214
 215 /**
 216  * fpga_bridges_get_to_list - get a bridge, add it to a list
 217  *
 218  * @np: node pointer of a FPGA bridge
 219  * @info: fpga image specific information
 220  * @bridge_list: list of FPGA bridges
 221  *
 222  * Get an exclusive reference to the bridge and and it to the list.
 223  *
 224  * Return 0 for success, error code from of_fpga_bridge_get() othewise.
 225  */
 226 int fpga_bridge_get_to_list(struct device_node *np,
 227                             struct fpga_image_info *info,
 228                             struct list_head *bridge_list)
 229 {
 230         struct fpga_bridge *bridge;
 231         unsigned long flags;
 232
 233         bridge = of_fpga_bridge_get(np, info);
 234         if (IS_ERR(bridge))
 235                 return PTR_ERR(bridge);
 236
 237         spin_lock_irqsave(&bridge_list_lock, flags);
 238         list_add(&bridge->node, bridge_list);
 239         spin_unlock_irqrestore(&bridge_list_lock, flags);
 240
 241         return 0;
 242 }
 243 EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
 244
 245 static ssize_t name_show(struct device *dev,
 246                          struct device_attribute *attr, char *buf)
 247 {
 248         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 249
 250         return sprintf(buf, "%s\n", bridge->name);
 251 }
 252
 253 static ssize_t state_show(struct device *dev,
 254                           struct device_attribute *attr, char *buf)
 255 {
 256         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 257         int enable = 1;
 258
 259         if (bridge->br_ops && bridge->br_ops->enable_show)
 260                 enable = bridge->br_ops->enable_show(bridge);
 261
 262         return sprintf(buf, "%s\n", enable ? "enabled" : "disabled");
 263 }
 264
 265 static DEVICE_ATTR_RO(name);
 266 static DEVICE_ATTR_RO(state);
 267
 268 static struct attribute *fpga_bridge_attrs[] = {
 269         &dev_attr_name.attr,
 270         &dev_attr_state.attr,
 271         NULL,
 272 };
 273 ATTRIBUTE_GROUPS(fpga_bridge);
 274
 275 /**
 276  * fpga_bridge_register - register a fpga bridge driver
 277  * @dev:        FPGA bridge device from pdev
 278  * @name:       FPGA bridge name
 279  * @br_ops:     pointer to structure of fpga bridge ops
 280  * @priv:       FPGA bridge private data
 281  *
 282  * Return: 0 for success, error code otherwise.
 283  */
 284 int fpga_bridge_register(struct device *dev, const char *name,
 285                          const struct fpga_bridge_ops *br_ops, void *priv)
 286 {
 287         struct fpga_bridge *bridge;
 288         int id, ret = 0;
 289
 290         if (!name || !strlen(name)) {
 291                 dev_err(dev, "Attempt to register with no name!\n");
 292                 return -EINVAL;
 293         }
 294
 295         bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
 296         if (!bridge)
 297                 return -ENOMEM;
 298
 299         id = ida_simple_get(&fpga_bridge_ida, 0, 0, GFP_KERNEL);
 300         if (id < 0) {
 301                 ret = id;
 302                 goto error_kfree;
 303         }
 304
 305         mutex_init(&bridge->mutex);
 306         INIT_LIST_HEAD(&bridge->node);
 307
 308         bridge->name = name;
 309         bridge->br_ops = br_ops;
 310         bridge->priv = priv;
 311
 312         device_initialize(&bridge->dev);
 313         bridge->dev.class = fpga_bridge_class;
 314         bridge->dev.parent = dev;
 315         bridge->dev.of_node = dev->of_node;
 316         bridge->dev.id = id;
 317         dev_set_drvdata(dev, bridge);
 318
 319         ret = dev_set_name(&bridge->dev, "br%d", id);
 320         if (ret)
 321                 goto error_device;
 322
 323         ret = device_add(&bridge->dev);
 324         if (ret)
 325                 goto error_device;
 326
 327         of_platform_populate(dev->of_node, NULL, NULL, dev);
 328
 329         dev_info(bridge->dev.parent, "fpga bridge [%s] registered\n",
 330                  bridge->name);
 331
 332         return 0;
 333
 334 error_device:
 335         ida_simple_remove(&fpga_bridge_ida, id);
 336 error_kfree:
 337         kfree(bridge);
 338
 339         return ret;
 340 }
 341 EXPORT_SYMBOL_GPL(fpga_bridge_register);
 342
 343 /**
 344  * fpga_bridge_unregister - unregister a fpga bridge driver
 345  * @dev: FPGA bridge device from pdev
 346  */
 347 void fpga_bridge_unregister(struct device *dev)
 348 {
 349         struct fpga_bridge *bridge = dev_get_drvdata(dev);
 350
 351         /*
 352          * If the low level driver provides a method for putting bridge into
 353          * a desired state upon unregister, do it.
 354          */
 355         if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
 356                 bridge->br_ops->fpga_bridge_remove(bridge);
 357
 358         device_unregister(&bridge->dev);
 359 }
 360 EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
 361
 362 static void fpga_bridge_dev_release(struct device *dev)
 363 {
 364         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 365
 366         ida_simple_remove(&fpga_bridge_ida, bridge->dev.id);
 367         kfree(bridge);
 368 }
 369
 370 static int __init fpga_bridge_dev_init(void)
 371 {
 372         spin_lock_init(&bridge_list_lock);
 373
 374         fpga_bridge_class = class_create(THIS_MODULE, "fpga_bridge");
 375         if (IS_ERR(fpga_bridge_class))
 376                 return PTR_ERR(fpga_bridge_class);
 377
 378         fpga_bridge_class->dev_groups = fpga_bridge_groups;
 379         fpga_bridge_class->dev_release = fpga_bridge_dev_release;
 380
 381         return 0;
 382 }
 383
 384 static void __exit fpga_bridge_dev_exit(void)
 385 {
 386         class_destroy(fpga_bridge_class);
 387         ida_destroy(&fpga_bridge_ida);
 388 }
 389
 390 MODULE_DESCRIPTION("FPGA Bridge Driver");
 391 MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
 392 MODULE_LICENSE("GPL v2");
 393
 394 subsys_initcall(fpga_bridge_dev_init);
 395 module_exit(fpga_bridge_dev_exit);