diff options
Diffstat (limited to 'drivers/greybus/manifest.c')
| -rw-r--r-- | drivers/greybus/manifest.c | 533 |
1 files changed, 533 insertions, 0 deletions
diff --git a/drivers/greybus/manifest.c b/drivers/greybus/manifest.c new file mode 100644 index 000000000..dd7040697 --- /dev/null +++ b/drivers/greybus/manifest.c @@ -0,0 +1,533 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Greybus manifest parsing + * + * Copyright 2014-2015 Google Inc. + * Copyright 2014-2015 Linaro Ltd. + */ + +#include <linux/greybus.h> + +static const char *get_descriptor_type_string(u8 type) +{ + switch (type) { + case GREYBUS_TYPE_INVALID: + return "invalid"; + case GREYBUS_TYPE_STRING: + return "string"; + case GREYBUS_TYPE_INTERFACE: + return "interface"; + case GREYBUS_TYPE_CPORT: + return "cport"; + case GREYBUS_TYPE_BUNDLE: + return "bundle"; + default: + WARN_ON(1); + return "unknown"; + } +} + +/* + * We scan the manifest once to identify where all the descriptors + * are. The result is a list of these manifest_desc structures. We + * then pick through them for what we're looking for (starting with + * the interface descriptor). As each is processed we remove it from + * the list. When we're done the list should (probably) be empty. + */ +struct manifest_desc { + struct list_head links; + + size_t size; + void *data; + enum greybus_descriptor_type type; +}; + +static void release_manifest_descriptor(struct manifest_desc *descriptor) +{ + list_del(&descriptor->links); + kfree(descriptor); +} + +static void release_manifest_descriptors(struct gb_interface *intf) +{ + struct manifest_desc *descriptor; + struct manifest_desc *next; + + list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links) + release_manifest_descriptor(descriptor); +} + +static void release_cport_descriptors(struct list_head *head, u8 bundle_id) +{ + struct manifest_desc *desc, *tmp; + struct greybus_descriptor_cport *desc_cport; + + list_for_each_entry_safe(desc, tmp, head, links) { + desc_cport = desc->data; + + if (desc->type != GREYBUS_TYPE_CPORT) + continue; + + if (desc_cport->bundle == bundle_id) + release_manifest_descriptor(desc); + } +} + +static struct manifest_desc *get_next_bundle_desc(struct gb_interface *intf) +{ + struct manifest_desc *descriptor; + struct manifest_desc *next; + + list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links) + if (descriptor->type == GREYBUS_TYPE_BUNDLE) + return descriptor; + + return NULL; +} + +/* + * Validate the given descriptor. Its reported size must fit within + * the number of bytes remaining, and it must have a recognized + * type. Check that the reported size is at least as big as what + * we expect to see. (It could be bigger, perhaps for a new version + * of the format.) + * + * Returns the (non-zero) number of bytes consumed by the descriptor, + * or a negative errno. + */ +static int identify_descriptor(struct gb_interface *intf, + struct greybus_descriptor *desc, size_t size) +{ + struct greybus_descriptor_header *desc_header = &desc->header; + struct manifest_desc *descriptor; + size_t desc_size; + size_t expected_size; + + if (size < sizeof(*desc_header)) { + dev_err(&intf->dev, "manifest too small (%zu < %zu)\n", size, + sizeof(*desc_header)); + return -EINVAL; /* Must at least have header */ + } + + desc_size = le16_to_cpu(desc_header->size); + if (desc_size > size) { + dev_err(&intf->dev, "descriptor too big (%zu > %zu)\n", + desc_size, size); + return -EINVAL; + } + + /* Descriptor needs to at least have a header */ + expected_size = sizeof(*desc_header); + + switch (desc_header->type) { + case GREYBUS_TYPE_STRING: + expected_size += sizeof(struct greybus_descriptor_string); + expected_size += desc->string.length; + + /* String descriptors are padded to 4 byte boundaries */ + expected_size = ALIGN(expected_size, 4); + break; + case GREYBUS_TYPE_INTERFACE: + expected_size += sizeof(struct greybus_descriptor_interface); + break; + case GREYBUS_TYPE_BUNDLE: + expected_size += sizeof(struct greybus_descriptor_bundle); + break; + case GREYBUS_TYPE_CPORT: + expected_size += sizeof(struct greybus_descriptor_cport); + break; + case GREYBUS_TYPE_INVALID: + default: + dev_err(&intf->dev, "invalid descriptor type (%u)\n", + desc_header->type); + return -EINVAL; + } + + if (desc_size < expected_size) { + dev_err(&intf->dev, "%s descriptor too small (%zu < %zu)\n", + get_descriptor_type_string(desc_header->type), + desc_size, expected_size); + return -EINVAL; + } + + /* Descriptor bigger than what we expect */ + if (desc_size > expected_size) { + dev_warn(&intf->dev, "%s descriptor size mismatch (want %zu got %zu)\n", + get_descriptor_type_string(desc_header->type), + expected_size, desc_size); + } + + descriptor = kzalloc(sizeof(*descriptor), GFP_KERNEL); + if (!descriptor) + return -ENOMEM; + + descriptor->size = desc_size; + descriptor->data = (char *)desc + sizeof(*desc_header); + descriptor->type = desc_header->type; + list_add_tail(&descriptor->links, &intf->manifest_descs); + + /* desc_size is positive and is known to fit in a signed int */ + + return desc_size; +} + +/* + * Find the string descriptor having the given id, validate it, and + * allocate a duplicate copy of it. The duplicate has an extra byte + * which guarantees the returned string is NUL-terminated. + * + * String index 0 is valid (it represents "no string"), and for + * that a null pointer is returned. + * + * Otherwise returns a pointer to a newly-allocated copy of the + * descriptor string, or an error-coded pointer on failure. + */ +static char *gb_string_get(struct gb_interface *intf, u8 string_id) +{ + struct greybus_descriptor_string *desc_string; + struct manifest_desc *descriptor; + bool found = false; + char *string; + + /* A zero string id means no string (but no error) */ + if (!string_id) + return NULL; + + list_for_each_entry(descriptor, &intf->manifest_descs, links) { + if (descriptor->type != GREYBUS_TYPE_STRING) + continue; + + desc_string = descriptor->data; + if (desc_string->id == string_id) { + found = true; + break; + } + } + if (!found) + return ERR_PTR(-ENOENT); + + /* Allocate an extra byte so we can guarantee it's NUL-terminated */ + string = kmemdup(&desc_string->string, desc_string->length + 1, + GFP_KERNEL); + if (!string) + return ERR_PTR(-ENOMEM); + string[desc_string->length] = '\0'; + + /* Ok we've used this string, so we're done with it */ + release_manifest_descriptor(descriptor); + + return string; +} + +/* + * Find cport descriptors in the manifest associated with the given + * bundle, and set up data structures for the functions that use + * them. Returns the number of cports set up for the bundle, or 0 + * if there is an error. + */ +static u32 gb_manifest_parse_cports(struct gb_bundle *bundle) +{ + struct gb_interface *intf = bundle->intf; + struct greybus_descriptor_cport *desc_cport; + struct manifest_desc *desc, *next, *tmp; + LIST_HEAD(list); + u8 bundle_id = bundle->id; + u16 cport_id; + u32 count = 0; + int i; + + /* Set up all cport descriptors associated with this bundle */ + list_for_each_entry_safe(desc, next, &intf->manifest_descs, links) { + if (desc->type != GREYBUS_TYPE_CPORT) + continue; + + desc_cport = desc->data; + if (desc_cport->bundle != bundle_id) + continue; + + cport_id = le16_to_cpu(desc_cport->id); + if (cport_id > CPORT_ID_MAX) + goto exit; + + /* Nothing else should have its cport_id as control cport id */ + if (cport_id == GB_CONTROL_CPORT_ID) { + dev_err(&bundle->dev, "invalid cport id found (%02u)\n", + cport_id); + goto exit; + } + + /* + * Found one, move it to our temporary list after checking for + * duplicates. + */ + list_for_each_entry(tmp, &list, links) { + desc_cport = tmp->data; + if (cport_id == le16_to_cpu(desc_cport->id)) { + dev_err(&bundle->dev, + "duplicate CPort %u found\n", cport_id); + goto exit; + } + } + list_move_tail(&desc->links, &list); + count++; + } + + if (!count) + return 0; + + bundle->cport_desc = kcalloc(count, sizeof(*bundle->cport_desc), + GFP_KERNEL); + if (!bundle->cport_desc) + goto exit; + + bundle->num_cports = count; + + i = 0; + list_for_each_entry_safe(desc, next, &list, links) { + desc_cport = desc->data; + memcpy(&bundle->cport_desc[i++], desc_cport, + sizeof(*desc_cport)); + + /* Release the cport descriptor */ + release_manifest_descriptor(desc); + } + + return count; +exit: + release_cport_descriptors(&list, bundle_id); + /* + * Free all cports for this bundle to avoid 'excess descriptors' + * warnings. + */ + release_cport_descriptors(&intf->manifest_descs, bundle_id); + + return 0; /* Error; count should also be 0 */ +} + +/* + * Find bundle descriptors in the manifest and set up their data + * structures. Returns the number of bundles set up for the + * given interface. + */ +static u32 gb_manifest_parse_bundles(struct gb_interface *intf) +{ + struct manifest_desc *desc; + struct gb_bundle *bundle; + struct gb_bundle *bundle_next; + u32 count = 0; + u8 bundle_id; + u8 class; + + while ((desc = get_next_bundle_desc(intf))) { + struct greybus_descriptor_bundle *desc_bundle; + + /* Found one. Set up its bundle structure*/ + desc_bundle = desc->data; + bundle_id = desc_bundle->id; + class = desc_bundle->class; + + /* Done with this bundle descriptor */ + release_manifest_descriptor(desc); + + /* Ignore any legacy control bundles */ + if (bundle_id == GB_CONTROL_BUNDLE_ID) { + dev_dbg(&intf->dev, "%s - ignoring control bundle\n", + __func__); + release_cport_descriptors(&intf->manifest_descs, + bundle_id); + continue; + } + + /* Nothing else should have its class set to control class */ + if (class == GREYBUS_CLASS_CONTROL) { + dev_err(&intf->dev, + "bundle %u cannot use control class\n", + bundle_id); + goto cleanup; + } + + bundle = gb_bundle_create(intf, bundle_id, class); + if (!bundle) + goto cleanup; + + /* + * Now go set up this bundle's functions and cports. + * + * A 'bundle' represents a device in greybus. It may require + * multiple cports for its functioning. If we fail to setup any + * cport of a bundle, we better reject the complete bundle as + * the device may not be able to function properly then. + * + * But, failing to setup a cport of bundle X doesn't mean that + * the device corresponding to bundle Y will not work properly. + * Bundles should be treated as separate independent devices. + * + * While parsing manifest for an interface, treat bundles as + * separate entities and don't reject entire interface and its + * bundles on failing to initialize a cport. But make sure the + * bundle which needs the cport, gets destroyed properly. + */ + if (!gb_manifest_parse_cports(bundle)) { + gb_bundle_destroy(bundle); + continue; + } + + count++; + } + + return count; +cleanup: + /* An error occurred; undo any changes we've made */ + list_for_each_entry_safe(bundle, bundle_next, &intf->bundles, links) { + gb_bundle_destroy(bundle); + count--; + } + return 0; /* Error; count should also be 0 */ +} + +static bool gb_manifest_parse_interface(struct gb_interface *intf, + struct manifest_desc *interface_desc) +{ + struct greybus_descriptor_interface *desc_intf = interface_desc->data; + struct gb_control *control = intf->control; + char *str; + + /* Handle the strings first--they can fail */ + str = gb_string_get(intf, desc_intf->vendor_stringid); + if (IS_ERR(str)) + return false; + control->vendor_string = str; + + str = gb_string_get(intf, desc_intf->product_stringid); + if (IS_ERR(str)) + goto out_free_vendor_string; + control->product_string = str; + + /* Assign feature flags communicated via manifest */ + intf->features = desc_intf->features; + + /* Release the interface descriptor, now that we're done with it */ + release_manifest_descriptor(interface_desc); + + /* An interface must have at least one bundle descriptor */ + if (!gb_manifest_parse_bundles(intf)) { + dev_err(&intf->dev, "manifest bundle descriptors not valid\n"); + goto out_err; + } + + return true; +out_err: + kfree(control->product_string); + control->product_string = NULL; +out_free_vendor_string: + kfree(control->vendor_string); + control->vendor_string = NULL; + + return false; +} + +/* + * Parse a buffer containing an interface manifest. + * + * If we find anything wrong with the content/format of the buffer + * we reject it. + * + * The first requirement is that the manifest's version is + * one we can parse. + * + * We make an initial pass through the buffer and identify all of + * the descriptors it contains, keeping track for each its type + * and the location size of its data in the buffer. + * + * Next we scan the descriptors, looking for an interface descriptor; + * there must be exactly one of those. When found, we record the + * information it contains, and then remove that descriptor (and any + * string descriptors it refers to) from further consideration. + * + * After that we look for the interface's bundles--there must be at + * least one of those. + * + * Returns true if parsing was successful, false otherwise. + */ +bool gb_manifest_parse(struct gb_interface *intf, void *data, size_t size) +{ + struct greybus_manifest *manifest; + struct greybus_manifest_header *header; + struct greybus_descriptor *desc; + struct manifest_desc *descriptor; + struct manifest_desc *interface_desc = NULL; + u16 manifest_size; + u32 found = 0; + bool result; + + /* Manifest descriptor list should be empty here */ + if (WARN_ON(!list_empty(&intf->manifest_descs))) + return false; + + /* we have to have at _least_ the manifest header */ + if (size < sizeof(*header)) { + dev_err(&intf->dev, "short manifest (%zu < %zu)\n", + size, sizeof(*header)); + return false; + } + + /* Make sure the size is right */ + manifest = data; + header = &manifest->header; + manifest_size = le16_to_cpu(header->size); + if (manifest_size != size) { + dev_err(&intf->dev, "manifest size mismatch (%zu != %u)\n", + size, manifest_size); + return false; + } + + /* Validate major/minor number */ + if (header->version_major > GREYBUS_VERSION_MAJOR) { + dev_err(&intf->dev, "manifest version too new (%u.%u > %u.%u)\n", + header->version_major, header->version_minor, + GREYBUS_VERSION_MAJOR, GREYBUS_VERSION_MINOR); + return false; + } + + /* OK, find all the descriptors */ + desc = manifest->descriptors; + size -= sizeof(*header); + while (size) { + int desc_size; + + desc_size = identify_descriptor(intf, desc, size); + if (desc_size < 0) { + result = false; + goto out; + } + desc = (struct greybus_descriptor *)((char *)desc + desc_size); + size -= desc_size; + } + + /* There must be a single interface descriptor */ + list_for_each_entry(descriptor, &intf->manifest_descs, links) { + if (descriptor->type == GREYBUS_TYPE_INTERFACE) + if (!found++) + interface_desc = descriptor; + } + if (found != 1) { + dev_err(&intf->dev, "manifest must have 1 interface descriptor (%u found)\n", + found); + result = false; + goto out; + } + + /* Parse the manifest, starting with the interface descriptor */ + result = gb_manifest_parse_interface(intf, interface_desc); + + /* + * We really should have no remaining descriptors, but we + * don't know what newer format manifests might leave. + */ + if (result && !list_empty(&intf->manifest_descs)) + dev_info(&intf->dev, "excess descriptors in interface manifest\n"); +out: + release_manifest_descriptors(intf); + + return result; +} |