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1// SPDX-License-Identifier: GPL-2.02/*3 * Greybus manifest parsing4 *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 descriptors32 * are. The result is a list of these manifest_desc structures. We33 * then pick through them for what we're looking for (starting with34 * the interface descriptor). As each is processed we remove it from35 * 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 within90 * the number of bytes remaining, and it must have a recognized91 * type. Check that the reported size is at least as big as what92 * we expect to see. (It could be bigger, perhaps for a new version93 * 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, and176 * allocate a duplicate copy of it. The duplicate has an extra byte177 * which guarantees the returned string is NUL-terminated.178 *179 * String index 0 is valid (it represents "no string"), and for180 * that a null pointer is returned.181 *182 * Otherwise returns a pointer to a newly-allocated copy of the183 * 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 given224 * bundle, and set up data structures for the functions that use225 * them. Returns the number of cports set up for the bundle, or 0226 * 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 for261 * 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 data309 * structures. Returns the number of bundles set up for the310 * 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 require357 * multiple cports for its functioning. If we fail to setup any358 * cport of a bundle, we better reject the complete bundle as359 * the device may not be able to function properly then.360 *361 * But, failing to setup a cport of bundle X doesn't mean that362 * 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 as366 * separate entities and don't reject entire interface and its367 * bundles on failing to initialize a cport. But make sure the368 * 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 buffer433 * we reject it.434 *435 * The first requirement is that the manifest's version is436 * one we can parse.437 *438 * We make an initial pass through the buffer and identify all of439 * the descriptors it contains, keeping track for each its type440 * 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 the444 * information it contains, and then remove that descriptor (and any445 * string descriptors it refers to) from further consideration.446 *447 * After that we look for the interface's bundles--there must be at448 * 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 we525 * 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