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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
The Greybus core code has been stable for a long time, and has been shipping for many years in millions of phones. With the advent of a recent Google Summer of Code project, and a number of new devices in the works from various companies, it is time to get the core greybus code out of staging as it really is going to be with us for a while. Cc: Johan Hovold <johan@kernel.org> Cc: linux-kernel@vger.kernel.org Cc: greybus-dev@lists.linaro.org Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Alex Elder <elder@kernel.org> Link: https://lore.kernel.org/r/20190825055429.18547-9-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
533 lines
14 KiB
C
533 lines
14 KiB
C
// 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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#include <linux/greybus.h>
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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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|
*/
|
|
if (result && !list_empty(&intf->manifest_descs))
|
|
dev_info(&intf->dev, "excess descriptors in interface manifest\n");
|
|
out:
|
|
release_manifest_descriptors(intf);
|
|
|
|
return result;
|
|
}
|