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 static 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         int ret;
 150
 151         list_for_each_entry(bridge, bridge_list, node) {
 152                 ret = fpga_bridge_enable(bridge);
 153                 if (ret)
 154                         return ret;
 155         }
 156
 157         return 0;
 158 }
 159 EXPORT_SYMBOL_GPL(fpga_bridges_enable);
 160
 161 /**
 162  * fpga_bridges_disable - disable bridges in a list
 163  *
 164  * @bridge_list: list of FPGA bridges
 165  *
 166  * Disable each bridge in the list.  If list is empty, do nothing.
 167  *
 168  * Return 0 for success or empty bridge list; return error code otherwise.
 169  */
 170 int fpga_bridges_disable(struct list_head *bridge_list)
 171 {
 172         struct fpga_bridge *bridge;
 173         int ret;
 174
 175         list_for_each_entry(bridge, bridge_list, node) {
 176                 ret = fpga_bridge_disable(bridge);
 177                 if (ret)
 178                         return ret;
 179         }
 180
 181         return 0;
 182 }
 183 EXPORT_SYMBOL_GPL(fpga_bridges_disable);
 184
 185 /**
 186  * fpga_bridges_put - put bridges
 187  *
 188  * @bridge_list: list of FPGA bridges
 189  *
 190  * For each bridge in the list, put the bridge and remove it from the list.
 191  * If list is empty, do nothing.
 192  */
 193 void fpga_bridges_put(struct list_head *bridge_list)
 194 {
 195         struct fpga_bridge *bridge, *next;
 196         unsigned long flags;
 197
 198         list_for_each_entry_safe(bridge, next, bridge_list, node) {
 199                 fpga_bridge_put(bridge);
 200
 201                 spin_lock_irqsave(&bridge_list_lock, flags);
 202                 list_del(&bridge->node);
 203                 spin_unlock_irqrestore(&bridge_list_lock, flags);
 204         }
 205 }
 206 EXPORT_SYMBOL_GPL(fpga_bridges_put);
 207
 208 /**
 209  * fpga_bridges_get_to_list - get a bridge, add it to a list
 210  *
 211  * @np: node pointer of a FPGA bridge
 212  * @info: fpga image specific information
 213  * @bridge_list: list of FPGA bridges
 214  *
 215  * Get an exclusive reference to the bridge and and it to the list.
 216  *
 217  * Return 0 for success, error code from of_fpga_bridge_get() othewise.
 218  */
 219 int fpga_bridge_get_to_list(struct device_node *np,
 220                             struct fpga_image_info *info,
 221                             struct list_head *bridge_list)
 222 {
 223         struct fpga_bridge *bridge;
 224         unsigned long flags;
 225
 226         bridge = of_fpga_bridge_get(np, info);
 227         if (IS_ERR(bridge))
 228                 return PTR_ERR(bridge);
 229
 230         spin_lock_irqsave(&bridge_list_lock, flags);
 231         list_add(&bridge->node, bridge_list);
 232         spin_unlock_irqrestore(&bridge_list_lock, flags);
 233
 234         return 0;
 235 }
 236 EXPORT_SYMBOL_GPL(fpga_bridge_get_to_list);
 237
 238 static ssize_t name_show(struct device *dev,
 239                          struct device_attribute *attr, char *buf)
 240 {
 241         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 242
 243         return sprintf(buf, "%s\n", bridge->name);
 244 }
 245
 246 static ssize_t state_show(struct device *dev,
 247                           struct device_attribute *attr, char *buf)
 248 {
 249         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 250         int enable = 1;
 251
 252         if (bridge->br_ops && bridge->br_ops->enable_show)
 253                 enable = bridge->br_ops->enable_show(bridge);
 254
 255         return sprintf(buf, "%s\n", enable ? "enabled" : "disabled");
 256 }
 257
 258 static DEVICE_ATTR_RO(name);
 259 static DEVICE_ATTR_RO(state);
 260
 261 static struct attribute *fpga_bridge_attrs[] = {
 262         &dev_attr_name.attr,
 263         &dev_attr_state.attr,
 264         NULL,
 265 };
 266 ATTRIBUTE_GROUPS(fpga_bridge);
 267
 268 /**
 269  * fpga_bridge_register - register a fpga bridge driver
 270  * @dev:        FPGA bridge device from pdev
 271  * @name:       FPGA bridge name
 272  * @br_ops:     pointer to structure of fpga bridge ops
 273  * @priv:       FPGA bridge private data
 274  *
 275  * Return: 0 for success, error code otherwise.
 276  */
 277 int fpga_bridge_register(struct device *dev, const char *name,
 278                          const struct fpga_bridge_ops *br_ops, void *priv)
 279 {
 280         struct fpga_bridge *bridge;
 281         int id, ret = 0;
 282
 283         if (!name || !strlen(name)) {
 284                 dev_err(dev, "Attempt to register with no name!\n");
 285                 return -EINVAL;
 286         }
 287
 288         bridge = kzalloc(sizeof(*bridge), GFP_KERNEL);
 289         if (!bridge)
 290                 return -ENOMEM;
 291
 292         id = ida_simple_get(&fpga_bridge_ida, 0, 0, GFP_KERNEL);
 293         if (id < 0) {
 294                 ret = id;
 295                 goto error_kfree;
 296         }
 297
 298         mutex_init(&bridge->mutex);
 299         INIT_LIST_HEAD(&bridge->node);
 300
 301         bridge->name = name;
 302         bridge->br_ops = br_ops;
 303         bridge->priv = priv;
 304
 305         device_initialize(&bridge->dev);
 306         bridge->dev.class = fpga_bridge_class;
 307         bridge->dev.parent = dev;
 308         bridge->dev.of_node = dev->of_node;
 309         bridge->dev.id = id;
 310         dev_set_drvdata(dev, bridge);
 311
 312         ret = dev_set_name(&bridge->dev, "br%d", id);
 313         if (ret)
 314                 goto error_device;
 315
 316         ret = device_add(&bridge->dev);
 317         if (ret)
 318                 goto error_device;
 319
 320         of_platform_populate(dev->of_node, NULL, NULL, dev);
 321
 322         dev_info(bridge->dev.parent, "fpga bridge [%s] registered\n",
 323                  bridge->name);
 324
 325         return 0;
 326
 327 error_device:
 328         ida_simple_remove(&fpga_bridge_ida, id);
 329 error_kfree:
 330         kfree(bridge);
 331
 332         return ret;
 333 }
 334 EXPORT_SYMBOL_GPL(fpga_bridge_register);
 335
 336 /**
 337  * fpga_bridge_unregister - unregister a fpga bridge driver
 338  * @dev: FPGA bridge device from pdev
 339  */
 340 void fpga_bridge_unregister(struct device *dev)
 341 {
 342         struct fpga_bridge *bridge = dev_get_drvdata(dev);
 343
 344         /*
 345          * If the low level driver provides a method for putting bridge into
 346          * a desired state upon unregister, do it.
 347          */
 348         if (bridge->br_ops && bridge->br_ops->fpga_bridge_remove)
 349                 bridge->br_ops->fpga_bridge_remove(bridge);
 350
 351         device_unregister(&bridge->dev);
 352 }
 353 EXPORT_SYMBOL_GPL(fpga_bridge_unregister);
 354
 355 static void fpga_bridge_dev_release(struct device *dev)
 356 {
 357         struct fpga_bridge *bridge = to_fpga_bridge(dev);
 358
 359         ida_simple_remove(&fpga_bridge_ida, bridge->dev.id);
 360         kfree(bridge);
 361 }
 362
 363 static int __init fpga_bridge_dev_init(void)
 364 {
 365         spin_lock_init(&bridge_list_lock);
 366
 367         fpga_bridge_class = class_create(THIS_MODULE, "fpga_bridge");
 368         if (IS_ERR(fpga_bridge_class))
 369                 return PTR_ERR(fpga_bridge_class);
 370
 371         fpga_bridge_class->dev_groups = fpga_bridge_groups;
 372         fpga_bridge_class->dev_release = fpga_bridge_dev_release;
 373
 374         return 0;
 375 }
 376
 377 static void __exit fpga_bridge_dev_exit(void)
 378 {
 379         class_destroy(fpga_bridge_class);
 380         ida_destroy(&fpga_bridge_ida);
 381 }
 382
 383 MODULE_DESCRIPTION("FPGA Bridge Driver");
 384 MODULE_AUTHOR("Alan Tull <[email protected]>");
 385 MODULE_LICENSE("GPL v2");
 386
 387 subsys_initcall(fpga_bridge_dev_init);
 388 module_exit(fpga_bridge_dev_exit);