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                 ret = PTR_ERR(mgr);
 249                 goto err_put_region;
 250         }
 251
 252         ret = fpga_region_get_bridges(region, overlay);
 253         if (ret) {
 254                 pr_err("failed to get fpga region bridges\n");
 255                 goto err_put_mgr;
 256         }
 257
 258         ret = fpga_bridges_disable(&region->bridge_list);
 259         if (ret) {
 260                 pr_err("failed to disable region bridges\n");
 261                 goto err_put_br;
 262         }
 263
 264         ret = fpga_mgr_firmware_load(mgr, region->info, firmware_name);
 265         if (ret) {
 266                 pr_err("failed to load fpga image\n");
 267                 goto err_put_br;
 268         }
 269
 270         ret = fpga_bridges_enable(&region->bridge_list);
 271         if (ret) {
 272                 pr_err("failed to enable region bridges\n");
 273                 goto err_put_br;
 274         }
 275
 276         fpga_mgr_put(mgr);
 277         fpga_region_put(region);
 278
 279         return 0;
 280
 281 err_put_br:
 282         fpga_bridges_put(&region->bridge_list);
 283 err_put_mgr:
 284         fpga_mgr_put(mgr);
 285 err_put_region:
 286         fpga_region_put(region);
 287
 288         return ret;
 289 }
 290
 291 /**
 292  * child_regions_with_firmware
 293  * @overlay: device node of the overlay
 294  *
 295  * If the overlay adds child FPGA regions, they are not allowed to have
 296  * firmware-name property.
 297  *
 298  * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
 299  */
 300 static int child_regions_with_firmware(struct device_node *overlay)
 301 {
 302         struct device_node *child_region;
 303         const char *child_firmware_name;
 304         int ret = 0;
 305
 306         of_node_get(overlay);
 307
 308         child_region = of_find_matching_node(overlay, fpga_region_of_match);
 309         while (child_region) {
 310                 if (!of_property_read_string(child_region, "firmware-name",
 311                                              &child_firmware_name)) {
 312                         ret = -EINVAL;
 313                         break;
 314                 }
 315                 child_region = of_find_matching_node(child_region,
 316                                                      fpga_region_of_match);
 317         }
 318
 319         of_node_put(child_region);
 320
 321         if (ret)
 322                 pr_err("firmware-name not allowed in child FPGA region: %s",
 323                        child_region->full_name);
 324
 325         return ret;
 326 }
 327
 328 /**
 329  * fpga_region_notify_pre_apply - pre-apply overlay notification
 330  *
 331  * @region: FPGA region that the overlay was applied to
 332  * @nd: overlay notification data
 333  *
 334  * Called after when an overlay targeted to a FPGA Region is about to be
 335  * applied.  Function will check the properties that will be added to the FPGA
 336  * region.  If the checks pass, it will program the FPGA.
 337  *
 338  * The checks are:
 339  * The overlay must add either firmware-name or external-fpga-config property
 340  * to the FPGA Region.
 341  *
 342  *   firmware-name         : program the FPGA
 343  *   external-fpga-config  : FPGA is already programmed
 344  *   encrypted-fpga-config : FPGA bitstream is encrypted
 345  *
 346  * The overlay can add other FPGA regions, but child FPGA regions cannot have a
 347  * firmware-name property since those regions don't exist yet.
 348  *
 349  * If the overlay that breaks the rules, notifier returns an error and the
 350  * overlay is rejected before it goes into the main tree.
 351  *
 352  * Returns 0 for success or negative error code for failure.
 353  */
 354 static int fpga_region_notify_pre_apply(struct fpga_region *region,
 355                                         struct of_overlay_notify_data *nd)
 356 {
 357         const char *firmware_name = NULL;
 358         struct fpga_image_info *info;
 359         int ret;
 360
 361         info = devm_kzalloc(&region->dev, sizeof(*info), GFP_KERNEL);
 362         if (!info)
 363                 return -ENOMEM;
 364
 365         region->info = info;
 366
 367         /* Reject overlay if child FPGA Regions have firmware-name property */
 368         ret = child_regions_with_firmware(nd->overlay);
 369         if (ret)
 370                 return ret;
 371
 372         /* Read FPGA region properties from the overlay */
 373         if (of_property_read_bool(nd->overlay, "partial-fpga-config"))
 374                 info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
 375
 376         if (of_property_read_bool(nd->overlay, "external-fpga-config"))
 377                 info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
 378
 379         if (of_property_read_bool(nd->overlay, "encrypted-fpga-config"))
 380                 info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
 381
 382         of_property_read_string(nd->overlay, "firmware-name", &firmware_name);
 383
 384         of_property_read_u32(nd->overlay, "region-unfreeze-timeout-us",
 385                              &info->enable_timeout_us);
 386
 387         of_property_read_u32(nd->overlay, "region-freeze-timeout-us",
 388                              &info->disable_timeout_us);
 389
 390         of_property_read_u32(nd->overlay, "config-complete-timeout-us",
 391                              &info->config_complete_timeout_us);
 392
 393         /* If FPGA was externally programmed, don't specify firmware */
 394         if ((info->flags & FPGA_MGR_EXTERNAL_CONFIG) && firmware_name) {
 395                 pr_err("error: specified firmware and external-fpga-config");
 396                 return -EINVAL;
 397         }
 398
 399         /* FPGA is already configured externally.  We're done. */
 400         if (info->flags & FPGA_MGR_EXTERNAL_CONFIG)
 401                 return 0;
 402
 403         /* If we got this far, we should be programming the FPGA */
 404         if (!firmware_name) {
 405                 pr_err("should specify firmware-name or external-fpga-config\n");
 406                 return -EINVAL;
 407         }
 408
 409         return fpga_region_program_fpga(region, firmware_name, nd->overlay);
 410 }
 411
 412 /**
 413  * fpga_region_notify_post_remove - post-remove overlay notification
 414  *
 415  * @region: FPGA region that was targeted by the overlay that was removed
 416  * @nd: overlay notification data
 417  *
 418  * Called after an overlay has been removed if the overlay's target was a
 419  * FPGA region.
 420  */
 421 static void fpga_region_notify_post_remove(struct fpga_region *region,
 422                                            struct of_overlay_notify_data *nd)
 423 {
 424         fpga_bridges_disable(&region->bridge_list);
 425         fpga_bridges_put(&region->bridge_list);
 426         devm_kfree(&region->dev, region->info);
 427         region->info = NULL;
 428 }
 429
 430 /**
 431  * of_fpga_region_notify - reconfig notifier for dynamic DT changes
 432  * @nb:         notifier block
 433  * @action:     notifier action
 434  * @arg:        reconfig data
 435  *
 436  * This notifier handles programming a FPGA when a "firmware-name" property is
 437  * added to a fpga-region.
 438  *
 439  * Returns NOTIFY_OK or error if FPGA programming fails.
 440  */
 441 static int of_fpga_region_notify(struct notifier_block *nb,
 442                                  unsigned long action, void *arg)
 443 {
 444         struct of_overlay_notify_data *nd = arg;
 445         struct fpga_region *region;
 446         int ret;
 447
 448         switch (action) {
 449         case OF_OVERLAY_PRE_APPLY:
 450                 pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
 451                 break;
 452         case OF_OVERLAY_POST_APPLY:
 453                 pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
 454                 return NOTIFY_OK;       /* not for us */
 455         case OF_OVERLAY_PRE_REMOVE:
 456                 pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
 457                 return NOTIFY_OK;       /* not for us */
 458         case OF_OVERLAY_POST_REMOVE:
 459                 pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
 460                 break;
 461         default:                        /* should not happen */
 462                 return NOTIFY_OK;
 463         }
 464
 465         region = fpga_region_find(nd->target);
 466         if (!region)
 467                 return NOTIFY_OK;
 468
 469         ret = 0;
 470         switch (action) {
 471         case OF_OVERLAY_PRE_APPLY:
 472                 ret = fpga_region_notify_pre_apply(region, nd);
 473                 break;
 474
 475         case OF_OVERLAY_POST_REMOVE:
 476                 fpga_region_notify_post_remove(region, nd);
 477                 break;
 478         }
 479
 480         put_device(&region->dev);
 481
 482         if (ret)
 483                 return notifier_from_errno(ret);
 484
 485         return NOTIFY_OK;
 486 }
 487
 488 static struct notifier_block fpga_region_of_nb = {
 489         .notifier_call = of_fpga_region_notify,
 490 };
 491
 492 static int fpga_region_probe(struct platform_device *pdev)
 493 {
 494         struct device *dev = &pdev->dev;
 495         struct device_node *np = dev->of_node;
 496         struct fpga_region *region;
 497         int id, ret = 0;
 498
 499         region = kzalloc(sizeof(*region), GFP_KERNEL);
 500         if (!region)
 501                 return -ENOMEM;
 502
 503         id = ida_simple_get(&fpga_region_ida, 0, 0, GFP_KERNEL);
 504         if (id < 0) {
 505                 ret = id;
 506                 goto err_kfree;
 507         }
 508
 509         mutex_init(&region->mutex);
 510         INIT_LIST_HEAD(&region->bridge_list);
 511
 512         device_initialize(&region->dev);
 513         region->dev.class = fpga_region_class;
 514         region->dev.parent = dev;
 515         region->dev.of_node = np;
 516         region->dev.id = id;
 517         dev_set_drvdata(dev, region);
 518
 519         ret = dev_set_name(&region->dev, "region%d", id);
 520         if (ret)
 521                 goto err_remove;
 522
 523         ret = device_add(&region->dev);
 524         if (ret)
 525                 goto err_remove;
 526
 527         of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
 528
 529         dev_info(dev, "FPGA Region probed\n");
 530
 531         return 0;
 532
 533 err_remove:
 534         ida_simple_remove(&fpga_region_ida, id);
 535 err_kfree:
 536         kfree(region);
 537
 538         return ret;
 539 }
 540
 541 static int fpga_region_remove(struct platform_device *pdev)
 542 {
 543         struct fpga_region *region = platform_get_drvdata(pdev);
 544
 545         device_unregister(&region->dev);
 546
 547         return 0;
 548 }
 549
 550 static struct platform_driver fpga_region_driver = {
 551         .probe = fpga_region_probe,
 552         .remove = fpga_region_remove,
 553         .driver = {
 554                 .name   = "fpga-region",
 555                 .of_match_table = of_match_ptr(fpga_region_of_match),
 556         },
 557 };
 558
 559 static void fpga_region_dev_release(struct device *dev)
 560 {
 561         struct fpga_region *region = to_fpga_region(dev);
 562
 563         ida_simple_remove(&fpga_region_ida, region->dev.id);
 564         kfree(region);
 565 }
 566
 567 /**
 568  * fpga_region_init - init function for fpga_region class
 569  * Creates the fpga_region class and registers a reconfig notifier.
 570  */
 571 static int __init fpga_region_init(void)
 572 {
 573         int ret;
 574
 575         fpga_region_class = class_create(THIS_MODULE, "fpga_region");
 576         if (IS_ERR(fpga_region_class))
 577                 return PTR_ERR(fpga_region_class);
 578
 579         fpga_region_class->dev_release = fpga_region_dev_release;
 580
 581         ret = of_overlay_notifier_register(&fpga_region_of_nb);
 582         if (ret)
 583                 goto err_class;
 584
 585         ret = platform_driver_register(&fpga_region_driver);
 586         if (ret)
 587                 goto err_plat;
 588
 589         return 0;
 590
 591 err_plat:
 592         of_overlay_notifier_unregister(&fpga_region_of_nb);
 593 err_class:
 594         class_destroy(fpga_region_class);
 595         ida_destroy(&fpga_region_ida);
 596         return ret;
 597 }
 598
 599 static void __exit fpga_region_exit(void)
 600 {
 601         platform_driver_unregister(&fpga_region_driver);
 602         of_overlay_notifier_unregister(&fpga_region_of_nb);
 603         class_destroy(fpga_region_class);
 604         ida_destroy(&fpga_region_ida);
 605 }
 606
 607 subsys_initcall(fpga_region_init);
 608 module_exit(fpga_region_exit);
 609
 610 MODULE_DESCRIPTION("FPGA Region");
 611 MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
 612 MODULE_LICENSE("GPL v2");