drivers/fpga/of-fpga-region.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * FPGA Region - Device Tree support for FPGA programming under Linux
   4  *
   5  *  Copyright (C) 2013-2016 Altera Corporation
   6  *  Copyright (C) 2017 Intel Corporation
   7  */
   8 #include <linux/fpga/fpga-bridge.h>
   9 #include <linux/fpga/fpga-mgr.h>
  10 #include <linux/fpga/fpga-region.h>
  11 #include <linux/idr.h>
  12 #include <linux/kernel.h>
  13 #include <linux/list.h>
  14 #include <linux/module.h>
  15 #include <linux/of_platform.h>
  16 #include <linux/slab.h>
  17 #include <linux/spinlock.h>
  18
  19 static const struct of_device_id fpga_region_of_match[] = {
  20         { .compatible = "fpga-region", },
  21         {},
  22 };
  23 MODULE_DEVICE_TABLE(of, fpga_region_of_match);
  24
  25 /**
  26  * of_fpga_region_find - find FPGA region
  27  * @np: device node of FPGA Region
  28  *
  29  * Caller will need to put_device(&region->dev) when done.
  30  *
  31  * Returns FPGA Region struct or NULL
  32  */
  33 static struct fpga_region *of_fpga_region_find(struct device_node *np)
  34 {
  35         return fpga_region_class_find(NULL, np, device_match_of_node);
  36 }
  37
  38 /**
  39  * of_fpga_region_get_mgr - get reference for FPGA manager
  40  * @np: device node of FPGA region
  41  *
  42  * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
  43  *
  44  * Caller should call fpga_mgr_put() when done with manager.
  45  *
  46  * Return: fpga manager struct or IS_ERR() condition containing error code.
  47  */
  48 static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
  49 {
  50         struct device_node  *mgr_node;
  51         struct fpga_manager *mgr;
  52
  53         of_node_get(np);
  54         while (np) {
  55                 if (of_device_is_compatible(np, "fpga-region")) {
  56                         mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
  57                         if (mgr_node) {
  58                                 mgr = of_fpga_mgr_get(mgr_node);
  59                                 of_node_put(mgr_node);
  60                                 of_node_put(np);
  61                                 return mgr;
  62                         }
  63                 }
  64                 np = of_get_next_parent(np);
  65         }
  66         of_node_put(np);
  67
  68         return ERR_PTR(-EINVAL);
  69 }
  70
  71 /**
  72  * of_fpga_region_get_bridges - create a list of bridges
  73  * @region: FPGA region
  74  *
  75  * Create a list of bridges including the parent bridge and the bridges
  76  * specified by "fpga-bridges" property.  Note that the
  77  * fpga_bridges_enable/disable/put functions are all fine with an empty list
  78  * if that happens.
  79  *
  80  * Caller should call fpga_bridges_put(&region->bridge_list) when
  81  * done with the bridges.
  82  *
  83  * Return 0 for success (even if there are no bridges specified)
  84  * or -EBUSY if any of the bridges are in use.
  85  */
  86 static int of_fpga_region_get_bridges(struct fpga_region *region)
  87 {
  88         struct device *dev = &region->dev;
  89         struct device_node *region_np = dev->of_node;
  90         struct fpga_image_info *info = region->info;
  91         struct device_node *br, *np, *parent_br = NULL;
  92         int i, ret;
  93
  94         /* If parent is a bridge, add to list */
  95         ret = of_fpga_bridge_get_to_list(region_np->parent, info,
  96                                          &region->bridge_list);
  97
  98         /* -EBUSY means parent is a bridge that is under use. Give up. */
  99         if (ret == -EBUSY)
 100                 return ret;
 101
 102         /* Zero return code means parent was a bridge and was added to list. */
 103         if (!ret)
 104                 parent_br = region_np->parent;
 105
 106         /* If overlay has a list of bridges, use it. */
 107         br = of_parse_phandle(info->overlay, "fpga-bridges", 0);
 108         if (br) {
 109                 of_node_put(br);
 110                 np = info->overlay;
 111         } else {
 112                 np = region_np;
 113         }
 114
 115         for (i = 0; ; i++) {
 116                 br = of_parse_phandle(np, "fpga-bridges", i);
 117                 if (!br)
 118                         break;
 119
 120                 /* If parent bridge is in list, skip it. */
 121                 if (br == parent_br) {
 122                         of_node_put(br);
 123                         continue;
 124                 }
 125
 126                 /* If node is a bridge, get it and add to list */
 127                 ret = of_fpga_bridge_get_to_list(br, info,
 128                                                  &region->bridge_list);
 129                 of_node_put(br);
 130
 131                 /* If any of the bridges are in use, give up */
 132                 if (ret == -EBUSY) {
 133                         fpga_bridges_put(&region->bridge_list);
 134                         return -EBUSY;
 135                 }
 136         }
 137
 138         return 0;
 139 }
 140
 141 /**
 142  * child_regions_with_firmware
 143  * @overlay: device node of the overlay
 144  *
 145  * If the overlay adds child FPGA regions, they are not allowed to have
 146  * firmware-name property.
 147  *
 148  * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
 149  */
 150 static int child_regions_with_firmware(struct device_node *overlay)
 151 {
 152         struct device_node *child_region;
 153         const char *child_firmware_name;
 154         int ret = 0;
 155
 156         of_node_get(overlay);
 157
 158         child_region = of_find_matching_node(overlay, fpga_region_of_match);
 159         while (child_region) {
 160                 if (!of_property_read_string(child_region, "firmware-name",
 161                                              &child_firmware_name)) {
 162                         ret = -EINVAL;
 163                         break;
 164                 }
 165                 child_region = of_find_matching_node(child_region,
 166                                                      fpga_region_of_match);
 167         }
 168
 169         of_node_put(child_region);
 170
 171         if (ret)
 172                 pr_err("firmware-name not allowed in child FPGA region: %pOF",
 173                        child_region);
 174
 175         return ret;
 176 }
 177
 178 /**
 179  * of_fpga_region_parse_ov - parse and check overlay applied to region
 180  *
 181  * @region: FPGA region
 182  * @overlay: overlay applied to the FPGA region
 183  *
 184  * Given an overlay applied to a FPGA region, parse the FPGA image specific
 185  * info in the overlay and do some checking.
 186  *
 187  * Returns:
 188  *   NULL if overlay doesn't direct us to program the FPGA.
 189  *   fpga_image_info struct if there is an image to program.
 190  *   error code for invalid overlay.
 191  */
 192 static struct fpga_image_info *of_fpga_region_parse_ov(
 193                                                 struct fpga_region *region,
 194                                                 struct device_node *overlay)
 195 {
 196         struct device *dev = &region->dev;
 197         struct fpga_image_info *info;
 198         const char *firmware_name;
 199         int ret;
 200
 201         if (region->info) {
 202                 dev_err(dev, "Region already has overlay applied.\n");
 203                 return ERR_PTR(-EINVAL);
 204         }
 205
 206         /*
 207          * Reject overlay if child FPGA Regions added in the overlay have
 208          * firmware-name property (would mean that an FPGA region that has
 209          * not been added to the live tree yet is doing FPGA programming).
 210          */
 211         ret = child_regions_with_firmware(overlay);
 212         if (ret)
 213                 return ERR_PTR(ret);
 214
 215         info = fpga_image_info_alloc(dev);
 216         if (!info)
 217                 return ERR_PTR(-ENOMEM);
 218
 219         info->overlay = overlay;
 220
 221         /* Read FPGA region properties from the overlay */
 222         if (of_property_read_bool(overlay, "partial-fpga-config"))
 223                 info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
 224
 225         if (of_property_read_bool(overlay, "external-fpga-config"))
 226                 info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
 227
 228         if (of_property_read_bool(overlay, "encrypted-fpga-config"))
 229                 info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
 230
 231         if (!of_property_read_string(overlay, "firmware-name",
 232                                      &firmware_name)) {
 233                 info->firmware_name = devm_kstrdup(dev, firmware_name,
 234                                                    GFP_KERNEL);
 235                 if (!info->firmware_name)
 236                         return ERR_PTR(-ENOMEM);
 237         }
 238
 239         of_property_read_u32(overlay, "region-unfreeze-timeout-us",
 240                              &info->enable_timeout_us);
 241
 242         of_property_read_u32(overlay, "region-freeze-timeout-us",
 243                              &info->disable_timeout_us);
 244
 245         of_property_read_u32(overlay, "config-complete-timeout-us",
 246                              &info->config_complete_timeout_us);
 247
 248         /* If overlay is not programming the FPGA, don't need FPGA image info */
 249         if (!info->firmware_name) {
 250                 ret = 0;
 251                 goto ret_no_info;
 252         }
 253
 254         /*
 255          * If overlay informs us FPGA was externally programmed, specifying
 256          * firmware here would be ambiguous.
 257          */
 258         if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
 259                 dev_err(dev, "error: specified firmware and external-fpga-config");
 260                 ret = -EINVAL;
 261                 goto ret_no_info;
 262         }
 263
 264         return info;
 265 ret_no_info:
 266         fpga_image_info_free(info);
 267         return ERR_PTR(ret);
 268 }
 269
 270 /**
 271  * of_fpga_region_notify_pre_apply - pre-apply overlay notification
 272  *
 273  * @region: FPGA region that the overlay was applied to
 274  * @nd: overlay notification data
 275  *
 276  * Called when an overlay targeted to a FPGA Region is about to be applied.
 277  * Parses the overlay for properties that influence how the FPGA will be
 278  * programmed and does some checking. If the checks pass, programs the FPGA.
 279  * If the checks fail, overlay is rejected and does not get added to the
 280  * live tree.
 281  *
 282  * Returns 0 for success or negative error code for failure.
 283  */
 284 static int of_fpga_region_notify_pre_apply(struct fpga_region *region,
 285                                            struct of_overlay_notify_data *nd)
 286 {
 287         struct device *dev = &region->dev;
 288         struct fpga_image_info *info;
 289         int ret;
 290
 291         info = of_fpga_region_parse_ov(region, nd->overlay);
 292         if (IS_ERR(info))
 293                 return PTR_ERR(info);
 294
 295         /* If overlay doesn't program the FPGA, accept it anyway. */
 296         if (!info)
 297                 return 0;
 298
 299         if (region->info) {
 300                 dev_err(dev, "Region already has overlay applied.\n");
 301                 return -EINVAL;
 302         }
 303
 304         region->info = info;
 305         ret = fpga_region_program_fpga(region);
 306         if (ret) {
 307                 /* error; reject overlay */
 308                 fpga_image_info_free(info);
 309                 region->info = NULL;
 310         }
 311
 312         return ret;
 313 }
 314
 315 /**
 316  * of_fpga_region_notify_post_remove - post-remove overlay notification
 317  *
 318  * @region: FPGA region that was targeted by the overlay that was removed
 319  * @nd: overlay notification data
 320  *
 321  * Called after an overlay has been removed if the overlay's target was a
 322  * FPGA region.
 323  */
 324 static void of_fpga_region_notify_post_remove(struct fpga_region *region,
 325                                               struct of_overlay_notify_data *nd)
 326 {
 327         fpga_bridges_disable(&region->bridge_list);
 328         fpga_bridges_put(&region->bridge_list);
 329         fpga_image_info_free(region->info);
 330         region->info = NULL;
 331 }
 332
 333 /**
 334  * of_fpga_region_notify - reconfig notifier for dynamic DT changes
 335  * @nb:         notifier block
 336  * @action:     notifier action
 337  * @arg:        reconfig data
 338  *
 339  * This notifier handles programming a FPGA when a "firmware-name" property is
 340  * added to a fpga-region.
 341  *
 342  * Returns NOTIFY_OK or error if FPGA programming fails.
 343  */
 344 static int of_fpga_region_notify(struct notifier_block *nb,
 345                                  unsigned long action, void *arg)
 346 {
 347         struct of_overlay_notify_data *nd = arg;
 348         struct fpga_region *region;
 349         int ret;
 350
 351         switch (action) {
 352         case OF_OVERLAY_PRE_APPLY:
 353                 pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
 354                 break;
 355         case OF_OVERLAY_POST_APPLY:
 356                 pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
 357                 return NOTIFY_OK;       /* not for us */
 358         case OF_OVERLAY_PRE_REMOVE:
 359                 pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
 360                 return NOTIFY_OK;       /* not for us */
 361         case OF_OVERLAY_POST_REMOVE:
 362                 pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
 363                 break;
 364         default:                        /* should not happen */
 365                 return NOTIFY_OK;
 366         }
 367
 368         region = of_fpga_region_find(nd->target);
 369         if (!region)
 370                 return NOTIFY_OK;
 371
 372         ret = 0;
 373         switch (action) {
 374         case OF_OVERLAY_PRE_APPLY:
 375                 ret = of_fpga_region_notify_pre_apply(region, nd);
 376                 break;
 377
 378         case OF_OVERLAY_POST_REMOVE:
 379                 of_fpga_region_notify_post_remove(region, nd);
 380                 break;
 381         }
 382
 383         put_device(&region->dev);
 384
 385         if (ret)
 386                 return notifier_from_errno(ret);
 387
 388         return NOTIFY_OK;
 389 }
 390
 391 static struct notifier_block fpga_region_of_nb = {
 392         .notifier_call = of_fpga_region_notify,
 393 };
 394
 395 static int of_fpga_region_probe(struct platform_device *pdev)
 396 {
 397         struct device *dev = &pdev->dev;
 398         struct device_node *np = dev->of_node;
 399         struct fpga_region *region;
 400         struct fpga_manager *mgr;
 401         int ret;
 402
 403         /* Find the FPGA mgr specified by region or parent region. */
 404         mgr = of_fpga_region_get_mgr(np);
 405         if (IS_ERR(mgr))
 406                 return -EPROBE_DEFER;
 407
 408         region = devm_fpga_region_create(dev, mgr, of_fpga_region_get_bridges);
 409         if (!region) {
 410                 ret = -ENOMEM;
 411                 goto eprobe_mgr_put;
 412         }
 413
 414         ret = fpga_region_register(region);
 415         if (ret)
 416                 goto eprobe_mgr_put;
 417
 418         of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
 419         platform_set_drvdata(pdev, region);
 420
 421         dev_info(dev, "FPGA Region probed\n");
 422
 423         return 0;
 424
 425 eprobe_mgr_put:
 426         fpga_mgr_put(mgr);
 427         return ret;
 428 }
 429
 430 static int of_fpga_region_remove(struct platform_device *pdev)
 431 {
 432         struct fpga_region *region = platform_get_drvdata(pdev);
 433         struct fpga_manager *mgr = region->mgr;
 434
 435         fpga_region_unregister(region);
 436         fpga_mgr_put(mgr);
 437
 438         return 0;
 439 }
 440
 441 static struct platform_driver of_fpga_region_driver = {
 442         .probe = of_fpga_region_probe,
 443         .remove = of_fpga_region_remove,
 444         .driver = {
 445                 .name   = "of-fpga-region",
 446                 .of_match_table = of_match_ptr(fpga_region_of_match),
 447         },
 448 };
 449
 450 /**
 451  * fpga_region_init - init function for fpga_region class
 452  * Creates the fpga_region class and registers a reconfig notifier.
 453  */
 454 static int __init of_fpga_region_init(void)
 455 {
 456         int ret;
 457
 458         ret = of_overlay_notifier_register(&fpga_region_of_nb);
 459         if (ret)
 460                 return ret;
 461
 462         ret = platform_driver_register(&of_fpga_region_driver);
 463         if (ret)
 464                 goto err_plat;
 465
 466         return 0;
 467
 468 err_plat:
 469         of_overlay_notifier_unregister(&fpga_region_of_nb);
 470         return ret;
 471 }
 472
 473 static void __exit of_fpga_region_exit(void)
 474 {
 475         platform_driver_unregister(&of_fpga_region_driver);
 476         of_overlay_notifier_unregister(&fpga_region_of_nb);
 477 }
 478
 479 subsys_initcall(of_fpga_region_init);
 480 module_exit(of_fpga_region_exit);
 481
 482 MODULE_DESCRIPTION("FPGA Region");
 483 MODULE_AUTHOR("Alan Tull <atull@kernel.org>");
 484 MODULE_LICENSE("GPL v2");