linux/drivers/fpga/fpga-region.c
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   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 */
  36struct 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
  45static DEFINE_IDA(fpga_region_ida);
  46static struct class *fpga_region_class;
  47
  48static const struct of_device_id fpga_region_of_match[] = {
  49        { .compatible = "fpga-region", },
  50        {},
  51};
  52MODULE_DEVICE_TABLE(of, fpga_region_of_match);
  53
  54static 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 */
  65static 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 */
  87static 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 */
 115static 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 */
 137static 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 */
 177static 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 */
 232static 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
 281err_put_br:
 282        fpga_bridges_put(&region->bridge_list);
 283err_put_mgr:
 284        fpga_mgr_put(mgr);
 285err_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 */
 300static 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: %pOF",
 323                       child_region);
 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 */
 354static 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 */
 421static 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 */
 441static 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
 488static struct notifier_block fpga_region_of_nb = {
 489        .notifier_call = of_fpga_region_notify,
 490};
 491
 492static 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
 533err_remove:
 534        ida_simple_remove(&fpga_region_ida, id);
 535err_kfree:
 536        kfree(region);
 537
 538        return ret;
 539}
 540
 541static 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
 550static 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
 559static 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 */
 571static 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
 591err_plat:
 592        of_overlay_notifier_unregister(&fpga_region_of_nb);
 593err_class:
 594        class_destroy(fpga_region_class);
 595        ida_destroy(&fpga_region_ida);
 596        return ret;
 597}
 598
 599static 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
 607subsys_initcall(fpga_region_init);
 608module_exit(fpga_region_exit);
 609
 610MODULE_DESCRIPTION("FPGA Region");
 611MODULE_AUTHOR("Alan Tull <atull@opensource.altera.com>");
 612MODULE_LICENSE("GPL v2");
 613