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