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