drivers/fpga/fpga-region.c

   1 /*
   2  * FPGA Region - Device Tree support for FPGA programming under Linux
   3  *
   4  *  Copyright (C) 2013-2016 Altera Corporation
   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
  19 #include <linux/fpga/fpga-bridge.h>
  20 #include <linux/fpga/fpga-mgr.h>
  21 #include <linux/idr.h>
  22 #include <linux/kernel.h>
  23 #include <linux/list.h>
  24 #include <linux/module.h>
  25 #include <linux/of_platform.h>
  26 #include <linux/slab.h>
  27 #include <linux/spinlock.h>
  28
  29 /**
  30  * struct fpga_region - FPGA Region structure
  31  * @dev: FPGA Region device
  32  * @mutex: enforces exclusive reference to region
  33  * @bridge_list: list of FPGA bridges specified in region
  34  * @info: fpga image specific information
  35  */
  36 struct fpga_region {
  37         struct device dev;
  38         struct mutex mutex; /* for exclusive reference to region */
  39         struct list_head bridge_list;
  40         struct fpga_image_info *info;
  41 };
  42
  43 #define to_fpga_region(d) container_of(d, struct fpga_region, dev)
  44
  45 static DEFINE_IDA(fpga_region_ida);
  46 static struct class *fpga_region_class;
  47
  48 static const struct of_device_id fpga_region_of_match[] = {
  49         { .compatible = "fpga-region", },
  50         {},
  51 };
  52 MODULE_DEVICE_TABLE(of, fpga_region_of_match);
  53
  54 static int fpga_region_of_node_match(struct device *dev, const void *data)
  55 {
  56         return dev->of_node == data;
  57 }
  58
  59 /**
  60  * fpga_region_find - find FPGA region
  61  * @np: device node of FPGA Region
  62  * Caller will need to put_device(&region->dev) when done.
  63  * Returns FPGA Region struct or NULL
  64  */
  65 static struct fpga_region *fpga_region_find(struct device_node *np)
  66 {
  67         struct device *dev;
  68
  69         dev = class_find_device(fpga_region_class, NULL, np,
  70                                 fpga_region_of_node_match);
  71         if (!dev)
  72                 return NULL;
  73
  74         return to_fpga_region(dev);
  75 }
  76
  77 /**
  78  * fpga_region_get - get an exclusive reference to a fpga region
  79  * @region: FPGA Region struct
  80  *
  81  * Caller should call fpga_region_put() when done with region.
  82  *
  83  * Return fpga_region struct if successful.
  84  * Return -EBUSY if someone already has a reference to the region.
  85  * Return -ENODEV if @np is not a FPGA Region.
  86  */
  87 static struct fpga_region *fpga_region_get(struct fpga_region *region)
  88 {
  89         struct device *dev = &region->dev;
  90
  91         if (!mutex_trylock(&region->mutex)) {
  92                 dev_dbg(dev, "%s: FPGA Region already in use\n", __func__);
  93                 return ERR_PTR(-EBUSY);
  94         }
  95
  96         get_device(dev);
  97         of_node_get(dev->of_node);
  98         if (!try_module_get(dev->parent->driver->owner)) {
  99                 of_node_put(dev->of_node);
 100                 put_device(dev);
 101                 mutex_unlock(&region->mutex);
 102                 return ERR_PTR(-ENODEV);
 103         }
 104
 105         dev_dbg(&region->dev, "get\n");
 106
 107         return region;
 108 }
 109
 110 /**
 111  * fpga_region_put - release a reference to a region
 112  *
 113  * @region: FPGA region
 114  */
 115 static void fpga_region_put(struct fpga_region *region)
 116 {
 117         struct device *dev = &region->dev;
 118
 119         dev_dbg(&region->dev, "put\n");
 120
 121         module_put(dev->parent->driver->owner);
 122         of_node_put(dev->of_node);
 123         put_device(dev);
 124         mutex_unlock(&region->mutex);
 125 }
 126
 127 /**
 128  * fpga_region_get_manager - get exclusive reference for FPGA manager
 129  * @region: FPGA region
 130  *
 131  * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
 132  *
 133  * Caller should call fpga_mgr_put() when done with manager.
 134  *
 135  * Return: fpga manager struct or IS_ERR() condition containing error code.
 136  */
 137 static struct fpga_manager *fpga_region_get_manager(struct fpga_region *region)
 138 {
 139         struct device *dev = &region->dev;
 140         struct device_node *np = dev->of_node;
 141         struct device_node  *mgr_node;
 142         struct fpga_manager *mgr;
 143
 144         of_node_get(np);
 145         while (np) {
 146                 if (of_device_is_compatible(np, "fpga-region")) {
 147                         mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
 148                         if (mgr_node) {
 149                                 mgr = of_fpga_mgr_get(mgr_node);
 150                                 of_node_put(np);
 151                                 return mgr;
 152                         }
 153                 }
 154                 np = of_get_next_parent(np);
 155         }
 156         of_node_put(np);
 157
 158         return ERR_PTR(-EINVAL);
 159 }
 160
 161 /**
 162  * fpga_region_get_bridges - create a list of bridges
 163  * @region: FPGA region
 164  * @overlay: device node of the overlay
 165  *
 166  * Create a list of bridges including the parent bridge and the bridges
 167  * specified by "fpga-bridges" property.  Note that the
 168  * fpga_bridges_enable/disable/put functions are all fine with an empty list
 169  * if that happens.
 170  *
 171  * Caller should call fpga_bridges_put(&region->bridge_list) when
 172  * done with the bridges.
 173  *
 174  * Return 0 for success (even if there are no bridges specified)
 175  * or -EBUSY if any of the bridges are in use.
 176  */
 177 static int fpga_region_get_bridges(struct fpga_region *region,
 178                                    struct device_node *overlay)
 179 {
 180         struct device *dev = &region->dev;
 181         struct device_node *region_np = dev->of_node;
 182         struct device_node *br, *np, *parent_br = NULL;
 183         int i, ret;
 184
 185         /* If parent is a bridge, add to list */
 186         ret = fpga_bridge_get_to_list(region_np->parent, region->info,
 187                                       &region->bridge_list);
 188         if (ret == -EBUSY)
 189                 return ret;
 190
 191         if (!ret)
 192                 parent_br = region_np->parent;
 193
 194         /* If overlay has a list of bridges, use it. */
 195         if (of_parse_phandle(overlay, "fpga-bridges", 0))
 196                 np = overlay;
 197         else
 198                 np = region_np;
 199
 200         for (i = 0; ; i++) {
 201                 br = of_parse_phandle(np, "fpga-bridges", i);
 202                 if (!br)
 203                         break;
 204
 205                 /* If parent bridge is in list, skip it. */
 206                 if (br == parent_br)
 207                         continue;
 208
 209                 /* If node is a bridge, get it and add to list */
 210                 ret = fpga_bridge_get_to_list(br, region->info,
 211                                               &region->bridge_list);
 212
 213                 /* If any of the bridges are in use, give up */
 214                 if (ret == -EBUSY) {
 215                         fpga_bridges_put(&region->bridge_list);
 216                         return -EBUSY;
 217                 }
 218         }
 219
 220         return 0;
 221 }
 222
 223 /**
 224  * fpga_region_program_fpga - program FPGA
 225  * @region: FPGA region
 226  * @firmware_name: name of FPGA image firmware file
 227  * @overlay: device node of the overlay
 228  * Program an FPGA using information in the device tree.
 229  * Function assumes that there is a firmware-name property.
 230  * Return 0 for success or negative error code.
 231  */
 232 static int fpga_region_program_fpga(struct fpga_region *region,
 233                                     const char *firmware_name,
 234                                     struct device_node *overlay)
 235 {
 236         struct fpga_manager *mgr;
 237         int ret;
 238
 239         region = fpga_region_get(region);
 240         if (IS_ERR(region)) {
 241                 pr_err("failed to get fpga region\n");
 242                 return PTR_ERR(region);
 243         }
 244
 245         mgr = fpga_region_get_manager(region);
 246         if (IS_ERR(mgr)) {
 247                 pr_err("failed to get fpga region manager\n");
 248                 return PTR_ERR(mgr);
 249         }
 250
 251         ret = fpga_region_get_bridges(region, overlay);
 252         if (ret) {
 253                 pr_err("failed to get fpga region bridges\n");
 254                 goto err_put_mgr;
 255         }
 256
 257         ret = fpga_bridges_disable(&region->bridge_list);
 258         if (ret) {
 259                 pr_err("failed to disable region bridges\n");
 260                 goto err_put_br;
 261         }
 262
 263         ret = fpga_mgr_firmware_load(mgr, region->info, firmware_name);
 264         if (ret) {
 265                 pr_err("failed to load fpga image\n");
 266                 goto err_put_br;
 267         }
 268
 269         ret = fpga_bridges_enable(&region->bridge_list);
 270         if (ret) {
 271                 pr_err("failed to enable region bridges\n");
 272                 goto err_put_br;
 273         }
 274
 275         fpga_mgr_put(mgr);
 276         fpga_region_put(region);
 277
 278         return 0;
 279
 280 err_put_br:
 281         fpga_bridges_put(&region->bridge_list);
 282 err_put_mgr:
 283         fpga_mgr_put(mgr);
 284         fpga_region_put(region);
 285
 286         return ret;
 287 }
 288
 289 /**
 290  * child_regions_with_firmware
 291  * @overlay: device node of the overlay
 292  *
 293  * If the overlay adds child FPGA regions, they are not allowed to have
 294  * firmware-name property.
 295  *
 296  * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
 297  */
 298 static int child_regions_with_firmware(struct device_node *overlay)
 299 {
 300         struct device_node *child_region;
 301         const char *child_firmware_name;
 302         int ret = 0;
 303
 304         of_node_get(overlay);
 305
 306         child_region = of_find_matching_node(overlay, fpga_region_of_match);
 307         while (child_region) {
 308                 if (!of_property_read_string(child_region, "firmware-name",
 309                                              &child_firmware_name)) {
 310                         ret = -EINVAL;
 311                         break;
 312                 }
 313                 child_region = of_find_matching_node(child_region,
 314                                                      fpga_region_of_match);
 315         }
 316
 317         of_node_put(child_region);
 318
 319         if (ret)
 320                 pr_err("firmware-name not allowed in child FPGA region: %s",
 321                        child_region->full_name);
 322
 323         return ret;
 324 }
 325
 326 /**
 327  * fpga_region_notify_pre_apply - pre-apply overlay notification
 328  *
 329  * @region: FPGA region that the overlay was applied to
 330  * @nd: overlay notification data
 331  *
 332  * Called after when an overlay targeted to a FPGA Region is about to be
 333  * applied.  Function will check the properties that will be added to the FPGA
 334  * region.  If the checks pass, it will program the FPGA.
 335  *
 336  * The checks are:
 337  * The overlay must add either firmware-name or external-fpga-config property
 338  * to the FPGA Region.
 339  *
 340  *   firmware-name        : program the FPGA
 341  *   external-fpga-config : FPGA is already programmed
 342  *
 343  * The overlay can add other FPGA regions, but child FPGA regions cannot have a
 344  * firmware-name property since those regions don't exist yet.
 345  *
 346  * If the overlay that breaks the rules, notifier returns an error and the
 347  * overlay is rejected before it goes into the main tree.
 348  *
 349  * Returns 0 for success or negative error code for failure.
 350  */
 351 static int fpga_region_notify_pre_apply(struct fpga_region *region,
 352                                         struct of_overlay_notify_data *nd)
 353 {
 354         const char *firmware_name = NULL;
 355         struct fpga_image_info *info;
 356         int ret;
 357
 358         info = devm_kzalloc(&region->dev, sizeof(*info), GFP_KERNEL);
 359         if (!info)
 360                 return -ENOMEM;
 361
 362         region->info = info;
 363
 364         /* Reject overlay if child FPGA Regions have firmware-name property */
 365         ret = child_regions_with_firmware(nd->overlay);
 366         if (ret)
 367                 return ret;
 368
 369         /* Read FPGA region properties from the overlay */
 370         if (of_property_read_bool(nd->overlay, "partial-fpga-config"))
 371                 info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
 372
 373         if (of_property_read_bool(nd->overlay, "external-fpga-config"))
 374                 info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
 375
 376         of_property_read_string(nd->overlay, "firmware-name", &firmware_name);
 377
 378         of_property_read_u32(nd->overlay, "region-unfreeze-timeout-us",
 379                              &info->enable_timeout_us);
 380
 381         of_property_read_u32(nd->overlay, "region-freeze-timeout-us",
 382                              &info->disable_timeout_us);
 383
 384         /* If FPGA was externally programmed, don't specify firmware */
 385         if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && firmware_name) {
 386                 pr_err("error: specified firmware and external-fpga-config");
 387                 return -EINVAL;
 388         }
 389
 390         /* FPGA is already configured externally.  We're done. */
 391         if (info->flags & FPGA_MGR_EXTERNAL_CONFIG)
 392                 return 0;
 393
 394         /* If we got this far, we should be programming the FPGA */
 395         if (!firmware_name) {
 396                 pr_err("should specify firmware-name or external-fpga-config\n");
 397                 return -EINVAL;
 398         }
 399
 400         return fpga_region_program_fpga(region, firmware_name, nd->overlay);
 401 }
 402
 403 /**
 404  * fpga_region_notify_post_remove - post-remove overlay notification
 405  *
 406  * @region: FPGA region that was targeted by the overlay that was removed
 407  * @nd: overlay notification data
 408  *
 409  * Called after an overlay has been removed if the overlay's target was a
 410  * FPGA region.
 411  */
 412 static void fpga_region_notify_post_remove(struct fpga_region *region,
 413                                            struct of_overlay_notify_data *nd)
 414 {
 415         fpga_bridges_disable(&region->bridge_list);
 416         fpga_bridges_put(&region->bridge_list);
 417         devm_kfree(&region->dev, region->info);
 418         region->info = NULL;
 419 }
 420
 421 /**
 422  * of_fpga_region_notify - reconfig notifier for dynamic DT changes
 423  * @nb:         notifier block
 424  * @action:     notifier action
 425  * @arg:        reconfig data
 426  *
 427  * This notifier handles programming a FPGA when a "firmware-name" property is
 428  * added to a fpga-region.
 429  *
 430  * Returns NOTIFY_OK or error if FPGA programming fails.
 431  */
 432 static int of_fpga_region_notify(struct notifier_block *nb,
 433                                  unsigned long action, void *arg)
 434 {
 435         struct of_overlay_notify_data *nd = arg;
 436         struct fpga_region *region;
 437         int ret;
 438
 439         switch (action) {
 440         case OF_OVERLAY_PRE_APPLY:
 441                 pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
 442                 break;
 443         case OF_OVERLAY_POST_APPLY:
 444                 pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
 445                 return NOTIFY_OK;       /* not for us */
 446         case OF_OVERLAY_PRE_REMOVE:
 447                 pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
 448                 return NOTIFY_OK;       /* not for us */
 449         case OF_OVERLAY_POST_REMOVE:
 450                 pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
 451                 break;
 452         default:                        /* should not happen */
 453                 return NOTIFY_OK;
 454         }
 455
 456         region = fpga_region_find(nd->target);
 457         if (!region)
 458                 return NOTIFY_OK;
 459
 460         ret = 0;
 461         switch (action) {
 462         case OF_OVERLAY_PRE_APPLY:
 463                 ret = fpga_region_notify_pre_apply(region, nd);
 464                 break;
 465
 466         case OF_OVERLAY_POST_REMOVE:
 467                 fpga_region_notify_post_remove(region, nd);
 468                 break;
 469         }
 470
 471         put_device(&region->dev);
 472
 473         if (ret)
 474                 return notifier_from_errno(ret);
 475
 476         return NOTIFY_OK;
 477 }
 478
 479 static struct notifier_block fpga_region_of_nb = {
 480         .notifier_call = of_fpga_region_notify,
 481 };
 482
 483 static int fpga_region_probe(struct platform_device *pdev)
 484 {
 485         struct device *dev = &pdev->dev;
 486         struct device_node *np = dev->of_node;
 487         struct fpga_region *region;
 488         int id, ret = 0;
 489
 490         region = kzalloc(sizeof(*region), GFP_KERNEL);
 491         if (!region)
 492                 return -ENOMEM;
 493
 494         id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
 495         if (id < 0) {
 496                 ret = id;
 497                 goto err_kfree;
 498         }
 499
 500         mutex_init(&region->mutex);
 501         INIT_LIST_HEAD(&region->bridge_list);
 502
 503         device_initialize(&region->dev);
 504         region->dev.class = fpga_region_class;
 505         region->dev.parent = dev;
 506         region->dev.of_node = np;
 507         region->dev.id = id;
 508         dev_set_drvdata(dev, region);
 509
 510         ret = dev_set_name(&region->dev, "region%d", id);
 511         if (ret)
 512                 goto err_remove;
 513
 514         ret = device_add(&region->dev);
 515         if (ret)
 516                 goto err_remove;
 517
 518         of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
 519
 520         dev_info(dev, "FPGA Region probed\n");
 521
 522         return 0;
 523
 524 err_remove:
 525         ida_simple_remove(&fpga_region_ida, id);
 526 err_kfree:
 527         kfree(region);
 528
 529         return ret;
 530 }
 531
 532 static int fpga_region_remove(struct platform_device *pdev)
 533 {
 534         struct fpga_region *region = platform_get_drvdata(pdev);
 535
 536         device_unregister(&region->dev);
 537
 538         return 0;
 539 }
 540
 541 static struct platform_driver fpga_region_driver = {
 542         .probe = fpga_region_probe,
 543         .remove = fpga_region_remove,
 544         .driver = {
 545                 .name   = "fpga-region",
 546                 .of_match_table = of_match_ptr(fpga_region_of_match),
 547         },
 548 };
 549
 550 static void fpga_region_dev_release(struct device *dev)
 551 {
 552         struct fpga_region *region = to_fpga_region(dev);
 553
 554         ida_simple_remove(&fpga_region_ida, region->dev.id);
 555         kfree(region);
 556 }
 557
 558 /**
 559  * fpga_region_init - init function for fpga_region class
 560  * Creates the fpga_region class and registers a reconfig notifier.
 561  */
 562 static int __init fpga_region_init(void)
 563 {
 564         int ret;
 565
 566         fpga_region_class = class_create(THIS_MODULE, "fpga_region");
 567         if (IS_ERR(fpga_region_class))
 568                 return PTR_ERR(fpga_region_class);
 569
 570         fpga_region_class->dev_release = fpga_region_dev_release;
 571
 572         ret = of_overlay_notifier_register(&fpga_region_of_nb);
 573         if (ret)
 574                 goto err_class;
 575
 576         ret = platform_driver_register(&fpga_region_driver);
 577         if (ret)
 578                 goto err_plat;
 579
 580         return 0;
 581
 582 err_plat:
 583         of_overlay_notifier_unregister(&fpga_region_of_nb);
 584 err_class:
 585         class_destroy(fpga_region_class);
 586         ida_destroy(&fpga_region_ida);
 587         return ret;
 588 }
 589
 590 static void __exit fpga_region_exit(void)
 591 {
 592         platform_driver_unregister(&fpga_region_driver);
 593         of_overlay_notifier_unregister(&fpga_region_of_nb);
 594         class_destroy(fpga_region_class);
 595         ida_destroy(&fpga_region_ida);
 596 }
 597
 598 subsys_initcall(fpga_region_init);
 599 module_exit(fpga_region_exit);
 600
 601 MODULE_DESCRIPTION("FPGA Region");
 602 MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
 603 MODULE_LICENSE("GPL v2");