1// SPDX-License-Identifier: GPL-2.0 2/* 3 * Greybus manifest parsing 4 * 5 * Copyright 2014-2015 Google Inc. 6 * Copyright 2014-2015 Linaro Ltd. 7 */ 8 9#include <linux/greybus.h> 10 11static const char *get_descriptor_type_string(u8 type) 12{ 13 switch (type) { 14 case GREYBUS_TYPE_INVALID: 15 return "invalid"; 16 case GREYBUS_TYPE_STRING: 17 return "string"; 18 case GREYBUS_TYPE_INTERFACE: 19 return "interface"; 20 case GREYBUS_TYPE_CPORT: 21 return "cport"; 22 case GREYBUS_TYPE_BUNDLE: 23 return "bundle"; 24 default: 25 WARN_ON(1); 26 return "unknown"; 27 } 28} 29 30/* 31 * We scan the manifest once to identify where all the descriptors 32 * are. The result is a list of these manifest_desc structures. We 33 * then pick through them for what we're looking for (starting with 34 * the interface descriptor). As each is processed we remove it from 35 * the list. When we're done the list should (probably) be empty. 36 */ 37struct manifest_desc { 38 struct list_head links; 39 40 size_t size; 41 void *data; 42 enum greybus_descriptor_type type; 43}; 44 45static void release_manifest_descriptor(struct manifest_desc *descriptor) 46{ 47 list_del(&descriptor->links); 48 kfree(descriptor); 49} 50 51static void release_manifest_descriptors(struct gb_interface *intf) 52{ 53 struct manifest_desc *descriptor; 54 struct manifest_desc *next; 55 56 list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links) 57 release_manifest_descriptor(descriptor); 58} 59 60static void release_cport_descriptors(struct list_head *head, u8 bundle_id) 61{ 62 struct manifest_desc *desc, *tmp; 63 struct greybus_descriptor_cport *desc_cport; 64 65 list_for_each_entry_safe(desc, tmp, head, links) { 66 desc_cport = desc->data; 67 68 if (desc->type != GREYBUS_TYPE_CPORT) 69 continue; 70 71 if (desc_cport->bundle == bundle_id) 72 release_manifest_descriptor(desc); 73 } 74} 75 76static struct manifest_desc *get_next_bundle_desc(struct gb_interface *intf) 77{ 78 struct manifest_desc *descriptor; 79 struct manifest_desc *next; 80 81 list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links) 82 if (descriptor->type == GREYBUS_TYPE_BUNDLE) 83 return descriptor; 84 85 return NULL; 86} 87 88/* 89 * Validate the given descriptor. Its reported size must fit within 90 * the number of bytes remaining, and it must have a recognized 91 * type. Check that the reported size is at least as big as what 92 * we expect to see. (It could be bigger, perhaps for a new version 93 * of the format.) 94 * 95 * Returns the (non-zero) number of bytes consumed by the descriptor, 96 * or a negative errno. 97 */ 98static int identify_descriptor(struct gb_interface *intf, 99 struct greybus_descriptor *desc, size_t size) 100{ 101 struct greybus_descriptor_header *desc_header = &desc->header; 102 struct manifest_desc *descriptor; 103 size_t desc_size; 104 size_t expected_size; 105 106 if (size < sizeof(*desc_header)) { 107 dev_err(&intf->dev, "manifest too small (%zu < %zu)\n", size, 108 sizeof(*desc_header)); 109 return -EINVAL; /* Must at least have header */ 110 } 111 112 desc_size = le16_to_cpu(desc_header->size); 113 if (desc_size > size) { 114 dev_err(&intf->dev, "descriptor too big (%zu > %zu)\n", 115 desc_size, size); 116 return -EINVAL; 117 } 118 119 /* Descriptor needs to at least have a header */ 120 expected_size = sizeof(*desc_header); 121 122 switch (desc_header->type) { 123 case GREYBUS_TYPE_STRING: 124 expected_size += sizeof(struct greybus_descriptor_string); 125 expected_size += desc->string.length; 126 127 /* String descriptors are padded to 4 byte boundaries */ 128 expected_size = ALIGN(expected_size, 4); 129 break; 130 case GREYBUS_TYPE_INTERFACE: 131 expected_size += sizeof(struct greybus_descriptor_interface); 132 break; 133 case GREYBUS_TYPE_BUNDLE: 134 expected_size += sizeof(struct greybus_descriptor_bundle); 135 break; 136 case GREYBUS_TYPE_CPORT: 137 expected_size += sizeof(struct greybus_descriptor_cport); 138 break; 139 case GREYBUS_TYPE_INVALID: 140 default: 141 dev_err(&intf->dev, "invalid descriptor type (%u)\n", 142 desc_header->type); 143 return -EINVAL; 144 } 145 146 if (desc_size < expected_size) { 147 dev_err(&intf->dev, "%s descriptor too small (%zu < %zu)\n", 148 get_descriptor_type_string(desc_header->type), 149 desc_size, expected_size); 150 return -EINVAL; 151 } 152 153 /* Descriptor bigger than what we expect */ 154 if (desc_size > expected_size) { 155 dev_warn(&intf->dev, "%s descriptor size mismatch (want %zu got %zu)\n", 156 get_descriptor_type_string(desc_header->type), 157 expected_size, desc_size); 158 } 159 160 descriptor = kzalloc(sizeof(*descriptor), GFP_KERNEL); 161 if (!descriptor) 162 return -ENOMEM; 163 164 descriptor->size = desc_size; 165 descriptor->data = (char *)desc + sizeof(*desc_header); 166 descriptor->type = desc_header->type; 167 list_add_tail(&descriptor->links, &intf->manifest_descs); 168 169 /* desc_size is positive and is known to fit in a signed int */ 170 171 return desc_size; 172} 173 174/* 175 * Find the string descriptor having the given id, validate it, and 176 * allocate a duplicate copy of it. The duplicate has an extra byte 177 * which guarantees the returned string is NUL-terminated. 178 * 179 * String index 0 is valid (it represents "no string"), and for 180 * that a null pointer is returned. 181 * 182 * Otherwise returns a pointer to a newly-allocated copy of the 183 * descriptor string, or an error-coded pointer on failure. 184 */ 185static char *gb_string_get(struct gb_interface *intf, u8 string_id) 186{ 187 struct greybus_descriptor_string *desc_string; 188 struct manifest_desc *descriptor; 189 bool found = false; 190 char *string; 191 192 /* A zero string id means no string (but no error) */ 193 if (!string_id) 194 return NULL; 195 196 list_for_each_entry(descriptor, &intf->manifest_descs, links) { 197 if (descriptor->type != GREYBUS_TYPE_STRING) 198 continue; 199 200 desc_string = descriptor->data; 201 if (desc_string->id == string_id) { 202 found = true; 203 break; 204 } 205 } 206 if (!found) 207 return ERR_PTR(-ENOENT); 208 209 /* Allocate an extra byte so we can guarantee it's NUL-terminated */ 210 string = kmemdup(&desc_string->string, desc_string->length + 1, 211 GFP_KERNEL); 212 if (!string) 213 return ERR_PTR(-ENOMEM); 214 string[desc_string->length] = '\0'; 215 216 /* Ok we've used this string, so we're done with it */ 217 release_manifest_descriptor(descriptor); 218 219 return string; 220} 221 222/* 223 * Find cport descriptors in the manifest associated with the given 224 * bundle, and set up data structures for the functions that use 225 * them. Returns the number of cports set up for the bundle, or 0 226 * if there is an error. 227 */ 228static u32 gb_manifest_parse_cports(struct gb_bundle *bundle) 229{ 230 struct gb_interface *intf = bundle->intf; 231 struct greybus_descriptor_cport *desc_cport; 232 struct manifest_desc *desc, *next, *tmp; 233 LIST_HEAD(list); 234 u8 bundle_id = bundle->id; 235 u16 cport_id; 236 u32 count = 0; 237 int i; 238 239 /* Set up all cport descriptors associated with this bundle */ 240 list_for_each_entry_safe(desc, next, &intf->manifest_descs, links) { 241 if (desc->type != GREYBUS_TYPE_CPORT) 242 continue; 243 244 desc_cport = desc->data; 245 if (desc_cport->bundle != bundle_id) 246 continue; 247 248 cport_id = le16_to_cpu(desc_cport->id); 249 if (cport_id > CPORT_ID_MAX) 250 goto exit; 251 252 /* Nothing else should have its cport_id as control cport id */ 253 if (cport_id == GB_CONTROL_CPORT_ID) { 254 dev_err(&bundle->dev, "invalid cport id found (%02u)\n", 255 cport_id); 256 goto exit; 257 } 258 259 /* 260 * Found one, move it to our temporary list after checking for 261 * duplicates. 262 */ 263 list_for_each_entry(tmp, &list, links) { 264 desc_cport = tmp->data; 265 if (cport_id == le16_to_cpu(desc_cport->id)) { 266 dev_err(&bundle->dev, 267 "duplicate CPort %u found\n", cport_id); 268 goto exit; 269 } 270 } 271 list_move_tail(&desc->links, &list); 272 count++; 273 } 274 275 if (!count) 276 return 0; 277 278 bundle->cport_desc = kcalloc(count, sizeof(*bundle->cport_desc), 279 GFP_KERNEL); 280 if (!bundle->cport_desc) 281 goto exit; 282 283 bundle->num_cports = count; 284 285 i = 0; 286 list_for_each_entry_safe(desc, next, &list, links) { 287 desc_cport = desc->data; 288 memcpy(&bundle->cport_desc[i++], desc_cport, 289 sizeof(*desc_cport)); 290 291 /* Release the cport descriptor */ 292 release_manifest_descriptor(desc); 293 } 294 295 return count; 296exit: 297 release_cport_descriptors(&list, bundle_id); 298 /* 299 * Free all cports for this bundle to avoid 'excess descriptors' 300 * warnings. 301 */ 302 release_cport_descriptors(&intf->manifest_descs, bundle_id); 303 304 return 0; /* Error; count should also be 0 */ 305} 306 307/* 308 * Find bundle descriptors in the manifest and set up their data 309 * structures. Returns the number of bundles set up for the 310 * given interface. 311 */ 312static u32 gb_manifest_parse_bundles(struct gb_interface *intf) 313{ 314 struct manifest_desc *desc; 315 struct gb_bundle *bundle; 316 struct gb_bundle *bundle_next; 317 u32 count = 0; 318 u8 bundle_id; 319 u8 class; 320 321 while ((desc = get_next_bundle_desc(intf))) { 322 struct greybus_descriptor_bundle *desc_bundle; 323 324 /* Found one. Set up its bundle structure*/ 325 desc_bundle = desc->data; 326 bundle_id = desc_bundle->id; 327 class = desc_bundle->class; 328 329 /* Done with this bundle descriptor */ 330 release_manifest_descriptor(desc); 331 332 /* Ignore any legacy control bundles */ 333 if (bundle_id == GB_CONTROL_BUNDLE_ID) { 334 dev_dbg(&intf->dev, "%s - ignoring control bundle\n", 335 __func__); 336 release_cport_descriptors(&intf->manifest_descs, 337 bundle_id); 338 continue; 339 } 340 341 /* Nothing else should have its class set to control class */ 342 if (class == GREYBUS_CLASS_CONTROL) { 343 dev_err(&intf->dev, 344 "bundle %u cannot use control class\n", 345 bundle_id); 346 goto cleanup; 347 } 348 349 bundle = gb_bundle_create(intf, bundle_id, class); 350 if (!bundle) 351 goto cleanup; 352 353 /* 354 * Now go set up this bundle's functions and cports. 355 * 356 * A 'bundle' represents a device in greybus. It may require 357 * multiple cports for its functioning. If we fail to setup any 358 * cport of a bundle, we better reject the complete bundle as 359 * the device may not be able to function properly then. 360 * 361 * But, failing to setup a cport of bundle X doesn't mean that 362 * the device corresponding to bundle Y will not work properly. 363 * Bundles should be treated as separate independent devices. 364 * 365 * While parsing manifest for an interface, treat bundles as 366 * separate entities and don't reject entire interface and its 367 * bundles on failing to initialize a cport. But make sure the 368 * bundle which needs the cport, gets destroyed properly. 369 */ 370 if (!gb_manifest_parse_cports(bundle)) { 371 gb_bundle_destroy(bundle); 372 continue; 373 } 374 375 count++; 376 } 377 378 return count; 379cleanup: 380 /* An error occurred; undo any changes we've made */ 381 list_for_each_entry_safe(bundle, bundle_next, &intf->bundles, links) { 382 gb_bundle_destroy(bundle); 383 count--; 384 } 385 return 0; /* Error; count should also be 0 */ 386} 387 388static bool gb_manifest_parse_interface(struct gb_interface *intf, 389 struct manifest_desc *interface_desc) 390{ 391 struct greybus_descriptor_interface *desc_intf = interface_desc->data; 392 struct gb_control *control = intf->control; 393 char *str; 394 395 /* Handle the strings first--they can fail */ 396 str = gb_string_get(intf, desc_intf->vendor_stringid); 397 if (IS_ERR(str)) 398 return false; 399 control->vendor_string = str; 400 401 str = gb_string_get(intf, desc_intf->product_stringid); 402 if (IS_ERR(str)) 403 goto out_free_vendor_string; 404 control->product_string = str; 405 406 /* Assign feature flags communicated via manifest */ 407 intf->features = desc_intf->features; 408 409 /* Release the interface descriptor, now that we're done with it */ 410 release_manifest_descriptor(interface_desc); 411 412 /* An interface must have at least one bundle descriptor */ 413 if (!gb_manifest_parse_bundles(intf)) { 414 dev_err(&intf->dev, "manifest bundle descriptors not valid\n"); 415 goto out_err; 416 } 417 418 return true; 419out_err: 420 kfree(control->product_string); 421 control->product_string = NULL; 422out_free_vendor_string: 423 kfree(control->vendor_string); 424 control->vendor_string = NULL; 425 426 return false; 427} 428 429/* 430 * Parse a buffer containing an interface manifest. 431 * 432 * If we find anything wrong with the content/format of the buffer 433 * we reject it. 434 * 435 * The first requirement is that the manifest's version is 436 * one we can parse. 437 * 438 * We make an initial pass through the buffer and identify all of 439 * the descriptors it contains, keeping track for each its type 440 * and the location size of its data in the buffer. 441 * 442 * Next we scan the descriptors, looking for an interface descriptor; 443 * there must be exactly one of those. When found, we record the 444 * information it contains, and then remove that descriptor (and any 445 * string descriptors it refers to) from further consideration. 446 * 447 * After that we look for the interface's bundles--there must be at 448 * least one of those. 449 * 450 * Returns true if parsing was successful, false otherwise. 451 */ 452bool gb_manifest_parse(struct gb_interface *intf, void *data, size_t size) 453{ 454 struct greybus_manifest *manifest; 455 struct greybus_manifest_header *header; 456 struct greybus_descriptor *desc; 457 struct manifest_desc *descriptor; 458 struct manifest_desc *interface_desc = NULL; 459 u16 manifest_size; 460 u32 found = 0; 461 bool result; 462 463 /* Manifest descriptor list should be empty here */ 464 if (WARN_ON(!list_empty(&intf->manifest_descs))) 465 return false; 466 467 /* we have to have at _least_ the manifest header */ 468 if (size < sizeof(*header)) { 469 dev_err(&intf->dev, "short manifest (%zu < %zu)\n", 470 size, sizeof(*header)); 471 return false; 472 } 473 474 /* Make sure the size is right */ 475 manifest = data; 476 header = &manifest->header; 477 manifest_size = le16_to_cpu(header->size); 478 if (manifest_size != size) { 479 dev_err(&intf->dev, "manifest size mismatch (%zu != %u)\n", 480 size, manifest_size); 481 return false; 482 } 483 484 /* Validate major/minor number */ 485 if (header->version_major > GREYBUS_VERSION_MAJOR) { 486 dev_err(&intf->dev, "manifest version too new (%u.%u > %u.%u)\n", 487 header->version_major, header->version_minor, 488 GREYBUS_VERSION_MAJOR, GREYBUS_VERSION_MINOR); 489 return false; 490 } 491 492 /* OK, find all the descriptors */ 493 desc = manifest->descriptors; 494 size -= sizeof(*header); 495 while (size) { 496 int desc_size; 497 498 desc_size = identify_descriptor(intf, desc, size); 499 if (desc_size < 0) { 500 result = false; 501 goto out; 502 } 503 desc = (struct greybus_descriptor *)((char *)desc + desc_size); 504 size -= desc_size; 505 } 506 507 /* There must be a single interface descriptor */ 508 list_for_each_entry(descriptor, &intf->manifest_descs, links) { 509 if (descriptor->type == GREYBUS_TYPE_INTERFACE) 510 if (!found++) 511 interface_desc = descriptor; 512 } 513 if (found != 1) { 514 dev_err(&intf->dev, "manifest must have 1 interface descriptor (%u found)\n", 515 found); 516 result = false; 517 goto out; 518 } 519 520 /* Parse the manifest, starting with the interface descriptor */ 521 result = gb_manifest_parse_interface(intf, interface_desc); 522 523 /* 524 * We really should have no remaining descriptors, but we 525 * don't know what newer format manifests might leave. 526 */ 527 if (result && !list_empty(&intf->manifest_descs)) 528 dev_info(&intf->dev, "excess descriptors in interface manifest\n"); 529out: 530 release_manifest_descriptors(intf); 531 532 return result; 533} 534