[linux-block.git] / drivers / staging / greybus / manifest.c

/*
 * Greybus module manifest parsing
 *
 * Copyright 2014 Google Inc.
 *
 * Released under the GPLv2 only.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/err.h>

#include "greybus.h"

/*
 * 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 module 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 LIST_HEAD(manifest_descs);

static void release_manifest_descriptor(struct manifest_desc *descriptor)
{
	list_del(&descriptor->links);
	kfree(descriptor);
}

static void release_manifest_descriptors(void)
{
	struct manifest_desc *descriptor;
	struct manifest_desc *next;

	list_for_each_entry_safe(descriptor, next, &manifest_descs, links)
		release_manifest_descriptor(descriptor);
}

/*
 * Validate the given descriptor.  Its reported size must fit within
 * the number of bytes reamining, 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 number of bytes consumed by the descriptor, or a
 * negative errno.
 */
static int identify_descriptor(struct greybus_descriptor *desc, size_t size)
{
	struct greybus_descriptor_header *desc_header = &desc->header;
	struct manifest_desc *descriptor;
	int desc_size;
	size_t expected_size;

	if (size < sizeof(*desc_header)) {
		pr_err("manifest too small\n");
		return -EINVAL;		/* Must at least have header */
	}

	desc_size = (int)le16_to_cpu(desc_header->size);
	if ((size_t)desc_size > size) {
		pr_err("descriptor too big\n");
		return -EINVAL;
	}

	switch (desc_header->type) {
	case GREYBUS_TYPE_MODULE:
		if (desc_size < sizeof(struct greybus_descriptor_module)) {
			pr_err("module descriptor too small (%u)\n",
				desc_size);
			return -EINVAL;
		}
		break;
	case GREYBUS_TYPE_STRING:
		expected_size = sizeof(struct greybus_descriptor_header);
		expected_size += sizeof(struct greybus_descriptor_string);
		expected_size += (size_t)desc->string.length;
		if (desc_size < expected_size) {
			pr_err("string descriptor too small (%u)\n",
				desc_size);
			return -EINVAL;
		}
		break;
	case GREYBUS_TYPE_INTERFACE:
		break;
	case GREYBUS_TYPE_CPORT:
		if (desc_size < sizeof(struct greybus_descriptor_cport)) {
			pr_err("cport descriptor too small (%u)\n",
				desc_size);
			return -EINVAL;
		}
		break;
	case GREYBUS_TYPE_CLASS:
		pr_warn("class descriptor found (ignoring)\n");
		break;
	case GREYBUS_TYPE_INVALID:
	default:
		pr_err("invalid descriptor type (%hhu)\n", desc_header->type);
		return -EINVAL;
	}

	descriptor = kzalloc(sizeof(*descriptor), GFP_KERNEL);
	if (!descriptor)
		return -ENOMEM;

	descriptor->size = desc_size;
	descriptor->data = (u8 *)desc + sizeof(*desc_header);
	descriptor->type = desc_header->type;
	list_add_tail(&descriptor->links, &manifest_descs);

	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(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, &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, (size_t)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 and set up data structures
 * for the functions that use them.  Returns the number of interfaces
 * set up for the given module, or 0 if there is an error.
 */
static u32 gb_manifest_parse_cports(struct gb_interface *interface)
{
	u32 count = 0;

	while (true) {
		struct manifest_desc *descriptor;
		struct greybus_descriptor_cport *desc_cport;
		u8 protocol_id;
		u16 cport_id;
		bool found;

		/* Find a cport descriptor */
		found = false;
		list_for_each_entry(descriptor, &manifest_descs, links) {
			if (descriptor->type == GREYBUS_TYPE_CPORT) {
				desc_cport = descriptor->data;
				if (desc_cport->interface == interface->id) {
					found = true;
					break;
				}
			}
		}
		if (!found)
			break;

		/* Found one.  Set up its function structure */
		protocol_id = desc_cport->protocol_id;
		cport_id = le16_to_cpu(desc_cport->id);
		if (!gb_connection_create(interface, cport_id, protocol_id))
			return 0;	/* Error */

		count++;
		/* Release the cport descriptor */
		release_manifest_descriptor(descriptor);
	}

	return count;
}

/*
 * Find interface descriptors in the manifest and set up their data
 * structures.  Returns the number of interfaces set up for the
 * given module.
 */
static u32 gb_manifest_parse_interfaces(struct gb_module *gmod)
{
	u32 count = 0;

	while (true) {
		struct manifest_desc *descriptor;
		struct greybus_descriptor_interface *desc_interface;
		struct gb_interface *interface;
		bool found = false;

		/* Find an interface descriptor */
		list_for_each_entry(descriptor, &manifest_descs, links) {
			if (descriptor->type == GREYBUS_TYPE_INTERFACE) {
				found = true;
				break;
			}
		}
		if (!found)
			break;

		/* Found one.  Set up its interface structure*/
		desc_interface = descriptor->data;
		interface = gb_interface_create(gmod, desc_interface->id);
		if (!interface)
			return 0;	/* Error */

		/* Now go set up this interface's functions and cports */
		if (!gb_manifest_parse_cports(interface))
			return 0;	/* Error parsing cports */

		count++;

		/* Done with this interface descriptor */
		release_manifest_descriptor(descriptor);
	}

	return count;
}

static bool gb_manifest_parse_module(struct gb_module *gmod,
					struct manifest_desc *module_desc)
{
	struct greybus_descriptor_module *desc_module = module_desc->data;

	/* Handle the strings first--they can fail */
	gmod->vendor_string = gb_string_get(desc_module->vendor_stringid);
	if (IS_ERR(gmod->vendor_string))
		return false;

	gmod->product_string = gb_string_get(desc_module->product_stringid);
	if (IS_ERR(gmod->product_string)) {
		goto out_err;
	}

	gmod->vendor = le16_to_cpu(desc_module->vendor);
	gmod->product = le16_to_cpu(desc_module->product);
	gmod->version = le16_to_cpu(desc_module->version);
	gmod->unique_id = le64_to_cpu(desc_module->unique_id);

	/* Release the module descriptor, now that we're done with it */
	release_manifest_descriptor(module_desc);

	/* A module must have at least one interface descriptor */
	if (!gb_manifest_parse_interfaces(gmod)) {
		pr_err("manifest interface descriptors not valid\n");
		goto out_err;
	}

	return true;
out_err:
	kfree(gmod->product_string);
	gmod->product_string = NULL;
	kfree(gmod->vendor_string);
	gmod->vendor_string = NULL;

	return false;
}

/*
 * Parse a buffer containing a module 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 a module 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 module's interfaces--there must be at
 * least one of those.
 *
 * Returns true if parsing was successful, false otherwise.
 */
bool gb_manifest_parse(struct gb_module *gmod, 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 *module_desc = NULL;
	u16 manifest_size;
	u32 found = 0;
	bool result;

	/* we have to have at _least_ the manifest header */
	if (size <= sizeof(manifest->header)) {
		pr_err("short manifest (%zu)\n", size);
		return false;
	}

	/* Make sure the size is right */
	manifest = data;
	header = &manifest->header;
	manifest_size = le16_to_cpu(header->size);
	if (manifest_size != size) {
		pr_err("manifest size mismatch %zu != %hu\n",
			size, manifest_size);
		return false;
	}

	/* Validate major/minor number */
	if (header->version_major > GREYBUS_VERSION_MAJOR) {
		pr_err("manifest version too new (%hhu.%hhu > %hhu.%hhu)\n",
			header->version_major, header->version_minor,
			GREYBUS_VERSION_MAJOR, GREYBUS_VERSION_MINOR);
		return false;
	}

	/* OK, find all the descriptors */
	desc = (struct greybus_descriptor *)(header + 1);
	size -= sizeof(*header);
	while (size) {
		int desc_size;

		desc_size = identify_descriptor(desc, size);
		if (desc_size <= 0) {
			if (!desc_size)
				pr_err("zero-sized manifest descriptor\n");
			result = false;
			goto out;
		}
		desc = (struct greybus_descriptor *)((char *)desc + desc_size);
		size -= desc_size;
	}

	/* There must be a single module descriptor */
	list_for_each_entry(descriptor, &manifest_descs, links) {
		if (descriptor->type == GREYBUS_TYPE_MODULE)
			if (!found++)
				module_desc = descriptor;
	}
	if (found != 1) {
		pr_err("manifest must have 1 module descriptor (%u found)\n",
			found);
		result = false;
		goto out;
	}

	/* Parse the module manifest, starting with the module descriptor */
	result = gb_manifest_parse_module(gmod, module_desc);

	/*
	 * We really should have no remaining descriptors, but we
	 * don't know what newer format manifests might leave.
	 */
	if (result && !list_empty(&manifest_descs))
		pr_info("excess descriptors in module manifest\n");
out:
	release_manifest_descriptors();

	return result;
}
Commit	Line	Data
b09c94a1 AE	1	/*
	2	* Greybus module manifest parsing
	3	*
	4	* Copyright 2014 Google Inc.
	5	*
	6	* Released under the GPLv2 only.
	7	*/
	8
	9	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	10
	11	#include <linux/err.h>
	12
	13	#include "greybus.h"
	14
	15	/*
	16	* We scan the manifest once to identify where all the descriptors
	17	* are. The result is a list of these manifest_desc structures. We
	18	* then pick through them for what we're looking for (starting with
	19	* the module descriptor). As each is processed we remove it from
	20	* the list. When we're done the list should (probably) be empty.
	21	*/
	22	struct manifest_desc {
	23	struct list_head links;
	24
	25	size_t size;
	26	void *data;
	27	enum greybus_descriptor_type type;
	28	};
	29
	30	static LIST_HEAD(manifest_descs);
	31
	32	static void release_manifest_descriptor(struct manifest_desc *descriptor)
	33	{
	34	list_del(&descriptor->links);
	35	kfree(descriptor);
	36	}
	37
	38	static void release_manifest_descriptors(void)
	39	{
	40	struct manifest_desc *descriptor;
	41	struct manifest_desc *next;
	42
	43	list_for_each_entry_safe(descriptor, next, &manifest_descs, links)
	44	release_manifest_descriptor(descriptor);
	45	}
	46
	47	/*
	48	* Validate the given descriptor. Its reported size must fit within
	49	* the number of bytes reamining, and it must have a recognized
	50	* type. Check that the reported size is at least as big as what
	51	* we expect to see. (It could be bigger, perhaps for a new version
	52	* of the format.)
	53	*
	54	* Returns the number of bytes consumed by the descriptor, or a
	55	* negative errno.
	56	*/
	57	static int identify_descriptor(struct greybus_descriptor *desc, size_t size)
	58	{
	59	struct greybus_descriptor_header *desc_header = &desc->header;
	60	struct manifest_desc *descriptor;
	61	int desc_size;
	62	size_t expected_size;
	63
	64	if (size < sizeof(*desc_header)) {
65	pr_err("manifest too small\n");
66	return -EINVAL; /* Must at least have header */
67	}
68
69	desc_size = (int)le16_to_cpu(desc_header->size);
70	if ((size_t)desc_size > size) {
71	pr_err("descriptor too big\n");
72	return -EINVAL;
73	}
74
75	switch (desc_header->type) {
76	case GREYBUS_TYPE_MODULE:
77	if (desc_size < sizeof(struct greybus_descriptor_module)) {
78	pr_err("module descriptor too small (%u)\n",
79	desc_size);
80	return -EINVAL;
81	}
82	break;
b09c94a1 AE	83	case GREYBUS_TYPE_STRING:
	84	expected_size = sizeof(struct greybus_descriptor_header);
	85	expected_size += sizeof(struct greybus_descriptor_string);
	86	expected_size += (size_t)desc->string.length;
	87	if (desc_size < expected_size) {
	88	pr_err("string descriptor too small (%u)\n",
	89	desc_size);
	90	return -EINVAL;
	91	}
	92	break;
63cc932b AE	93	case GREYBUS_TYPE_INTERFACE:
63cc932b AE	94	break;
b09c94a1 AE	95	case GREYBUS_TYPE_CPORT:
	96	if (desc_size < sizeof(struct greybus_descriptor_cport)) {
	97	pr_err("cport descriptor too small (%u)\n",
	98	desc_size);
	99	return -EINVAL;
	100	}
	101	break;
63cc932b AE	102	case GREYBUS_TYPE_CLASS:
	103	pr_warn("class descriptor found (ignoring)\n");
	104	break;
b09c94a1 AE	105	case GREYBUS_TYPE_INVALID:
	106	default:
	107	pr_err("invalid descriptor type (%hhu)\n", desc_header->type);
	108	return -EINVAL;
	109	}
	110
	111	descriptor = kzalloc(sizeof(*descriptor), GFP_KERNEL);
	112	if (!descriptor)
	113	return -ENOMEM;
	114
	115	descriptor->size = desc_size;
7a13e2f6	116	descriptor->data = (u8 )desc + sizeof(desc_header);
b09c94a1 AE	117	descriptor->type = desc_header->type;
	118	list_add_tail(&descriptor->links, &manifest_descs);
	119
	120	return desc_size;
	121	}
	122
	123	/*
	124	* Find the string descriptor having the given id, validate it, and
	125	* allocate a duplicate copy of it. The duplicate has an extra byte
	126	* which guarantees the returned string is NUL-terminated.
	127	*
	128	* String index 0 is valid (it represents "no string"), and for
	129	* that a null pointer is returned.
	130	*
	131	* Otherwise returns a pointer to a newly-allocated copy of the
	132	* descriptor string, or an error-coded pointer on failure.
	133	*/
	134	static char *gb_string_get(u8 string_id)
	135	{
	136	struct greybus_descriptor_string *desc_string;
	137	struct manifest_desc *descriptor;
	138	bool found = false;
	139	char *string;
	140
	141	/* A zero string id means no string (but no error) */
	142	if (!string_id)
	143	return NULL;
	144
	145	list_for_each_entry(descriptor, &manifest_descs, links) {
b09c94a1 AE	146
	147	if (descriptor->type != GREYBUS_TYPE_STRING)
	148	continue;
	149
7a13e2f6	150	desc_string = descriptor->data;
b09c94a1 AE	151	if (desc_string->id == string_id) {
	152	found = true;
	153	break;
	154	}
	155	}
	156	if (!found)
	157	return ERR_PTR(-ENOENT);
	158
	159	/* Allocate an extra byte so we can guarantee it's NUL-terminated */
	160	string = kmemdup(&desc_string->string, (size_t)desc_string->length + 1,
	161	GFP_KERNEL);
	162	if (!string)
	163	return ERR_PTR(-ENOMEM);
	164	string[desc_string->length] = '\0';
	165
	166	/* Ok we've used this string, so we're done with it */
	167	release_manifest_descriptor(descriptor);
	168
	169	return string;
	170	}
	171
c095bbcf AE	172	/*
	173	* Find cport descriptors in the manifest and set up data structures
	174	* for the functions that use them. Returns the number of interfaces
	175	* set up for the given module, or 0 if there is an error.
	176	*/
2f30d9ff	177	static u32 gb_manifest_parse_cports(struct gb_interface *interface)
c095bbcf AE	178	{
	179	u32 count = 0;
	180
	181	while (true) {
	182	struct manifest_desc *descriptor;
	183	struct greybus_descriptor_cport *desc_cport;
7fba0079	184	u8 protocol_id;
c095bbcf AE	185	u16 cport_id;
	186	bool found;
	187
	188	/* Find a cport descriptor */
	189	found = false;
	190	list_for_each_entry(descriptor, &manifest_descs, links) {
	191	if (descriptor->type == GREYBUS_TYPE_CPORT) {
63cc932b AE	192	desc_cport = descriptor->data;
	193	if (desc_cport->interface == interface->id) {
	194	found = true;
	195	break;
	196	}
c095bbcf AE	197	}
	198	}
	199	if (!found)
	200	break;
	201
	202	/* Found one. Set up its function structure */
7fba0079	203	protocol_id = desc_cport->protocol_id;
c095bbcf	204	cport_id = le16_to_cpu(desc_cport->id);
7fba0079	205	if (!gb_connection_create(interface, cport_id, protocol_id))
c095bbcf AE	206	return 0; /* Error */
	207
	208	count++;
	209	/* Release the cport descriptor */
	210	release_manifest_descriptor(descriptor);
	211	}
	212
	213	return count;
	214	}
	215
d88bfb5b AE	216	/*
	217	* Find interface descriptors in the manifest and set up their data
	218	* structures. Returns the number of interfaces set up for the
	219	* given module.
	220	*/
	221	static u32 gb_manifest_parse_interfaces(struct gb_module *gmod)
	222	{
	223	u32 count = 0;
	224
	225	while (true) {
	226	struct manifest_desc *descriptor;
	227	struct greybus_descriptor_interface *desc_interface;
	228	struct gb_interface *interface;
	229	bool found = false;
	230
	231	/* Find an interface descriptor */
	232	list_for_each_entry(descriptor, &manifest_descs, links) {
63cc932b	233	if (descriptor->type == GREYBUS_TYPE_INTERFACE) {
d88bfb5b AE	234	found = true;
	235	break;
	236	}
	237	}
	238	if (!found)
	239	break;
	240
	241	/* Found one. Set up its interface structure*/
	242	desc_interface = descriptor->data;
	243	interface = gb_interface_create(gmod, desc_interface->id);
	244	if (!interface)
	245	return 0; /* Error */
c095bbcf AE	246
	247	/* Now go set up this interface's functions and cports */
	248	if (!gb_manifest_parse_cports(interface))
	249	return 0; /* Error parsing cports */
	250
d88bfb5b AE	251	count++;
	252
	253	/* Done with this interface descriptor */
	254	release_manifest_descriptor(descriptor);
	255	}
	256
	257	return count;
	258	}
	259
937d0da8 AE	260	static bool gb_manifest_parse_module(struct gb_module *gmod,
937d0da8 AE	261	struct manifest_desc *module_desc)
b09c94a1	262	{
7a13e2f6	263	struct greybus_descriptor_module *desc_module = module_desc->data;
b09c94a1 AE	264
	265	/* Handle the strings first--they can fail */
	266	gmod->vendor_string = gb_string_get(desc_module->vendor_stringid);
937d0da8 AE	267	if (IS_ERR(gmod->vendor_string))
	268	return false;
	269
b09c94a1 AE	270	gmod->product_string = gb_string_get(desc_module->product_stringid);
b09c94a1 AE	271	if (IS_ERR(gmod->product_string)) {
937d0da8	272	goto out_err;
b09c94a1 AE	273	}
	274
	275	gmod->vendor = le16_to_cpu(desc_module->vendor);
	276	gmod->product = le16_to_cpu(desc_module->product);
	277	gmod->version = le16_to_cpu(desc_module->version);
63cc932b	278	gmod->unique_id = le64_to_cpu(desc_module->unique_id);
b09c94a1 AE	279
	280	/* Release the module descriptor, now that we're done with it */
	281	release_manifest_descriptor(module_desc);
	282
d88bfb5b AE	283	/* A module must have at least one interface descriptor */
	284	if (!gb_manifest_parse_interfaces(gmod)) {
	285	pr_err("manifest interface descriptors not valid\n");
937d0da8	286	goto out_err;
d88bfb5b AE	287	}
d88bfb5b AE	288
937d0da8 AE	289	return true;
	290	out_err:
	291	kfree(gmod->product_string);
	292	gmod->product_string = NULL;
	293	kfree(gmod->vendor_string);
	294	gmod->vendor_string = NULL;
	295
	296	return false;
b09c94a1 AE	297	}
	298
	299	/*
	300	* Parse a buffer containing a module manifest.
	301	*
	302	* If we find anything wrong with the content/format of the buffer
	303	* we reject it.
	304	*
	305	* The first requirement is that the manifest's version is
	306	* one we can parse.
	307	*
	308	* We make an initial pass through the buffer and identify all of
	309	* the descriptors it contains, keeping track for each its type
	310	* and the location size of its data in the buffer.
	311	*
	312	* Next we scan the descriptors, looking for a module descriptor;
	313	* there must be exactly one of those. When found, we record the
	314	* information it contains, and then remove that descriptor (and any
	315	* string descriptors it refers to) from further consideration.
	316	*
	317	* After that we look for the module's interfaces--there must be at
	318	* least one of those.
	319	*
937d0da8	320	* Returns true if parsing was successful, false otherwise.
b09c94a1	321	*/
937d0da8	322	bool gb_manifest_parse(struct gb_module gmod, void data, size_t size)
b09c94a1 AE	323	{
	324	struct greybus_manifest *manifest;
	325	struct greybus_manifest_header *header;
	326	struct greybus_descriptor *desc;
	327	struct manifest_desc *descriptor;
2fb5c518	328	struct manifest_desc *module_desc = NULL;
b09c94a1 AE	329	u16 manifest_size;
b09c94a1 AE	330	u32 found = 0;
43d9431f	331	bool result;
b09c94a1 AE	332
	333	/* we have to have at _least_ the manifest header */
	334	if (size <= sizeof(manifest->header)) {
	335	pr_err("short manifest (%zu)\n", size);
937d0da8	336	return false;
b09c94a1 AE	337	}
	338
	339	/* Make sure the size is right */
	340	manifest = data;
	341	header = &manifest->header;
	342	manifest_size = le16_to_cpu(header->size);
	343	if (manifest_size != size) {
	344	pr_err("manifest size mismatch %zu != %hu\n",
	345	size, manifest_size);
937d0da8	346	return false;
b09c94a1 AE	347	}
	348
	349	/* Validate major/minor number */
	350	if (header->version_major > GREYBUS_VERSION_MAJOR) {
	351	pr_err("manifest version too new (%hhu.%hhu > %hhu.%hhu)\n",
	352	header->version_major, header->version_minor,
	353	GREYBUS_VERSION_MAJOR, GREYBUS_VERSION_MINOR);
937d0da8	354	return false;
b09c94a1 AE	355	}
	356
	357	/* OK, find all the descriptors */
	358	desc = (struct greybus_descriptor *)(header + 1);
	359	size -= sizeof(*header);
	360	while (size) {
	361	int desc_size;
	362
	363	desc_size = identify_descriptor(desc, size);
	364	if (desc_size <= 0) {
	365	if (!desc_size)
	366	pr_err("zero-sized manifest descriptor\n");
ff8aed52	367	result = false;
937d0da8	368	goto out;
b09c94a1 AE	369	}
	370	desc = (struct greybus_descriptor )((char )desc + desc_size);
	371	size -= desc_size;
	372	}
	373
	374	/* There must be a single module descriptor */
	375	list_for_each_entry(descriptor, &manifest_descs, links) {
	376	if (descriptor->type == GREYBUS_TYPE_MODULE)
	377	if (!found++)
	378	module_desc = descriptor;
	379	}
	380	if (found != 1) {
	381	pr_err("manifest must have 1 module descriptor (%u found)\n",
	382	found);
ff8aed52	383	result = false;
937d0da8	384	goto out;
b09c94a1 AE	385	}
	386
	387	/* Parse the module manifest, starting with the module descriptor */
937d0da8	388	result = gb_manifest_parse_module(gmod, module_desc);
b09c94a1 AE	389
	390	/*
	391	* We really should have no remaining descriptors, but we
	392	* don't know what newer format manifests might leave.
	393	*/
545a6975	394	if (result && !list_empty(&manifest_descs))
b09c94a1	395	pr_info("excess descriptors in module manifest\n");
937d0da8	396	out:
b09c94a1 AE	397	release_manifest_descriptors();
b09c94a1 AE	398
ff8aed52	399	return result;
b09c94a1	400	}