1 files changed, 533 insertions, 0 deletions

diff --git a/drivers/greybus/manifest.c b/drivers/greybus/manifest.c
new file mode 100644
index 000000000000..dd7040697bde
--- /dev/null
+++ b/drivers/greybus/manifest.c
@@ -0,0 +1,533 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Greybus manifest parsing
+ *
+ * Copyright 2014-2015 Google Inc.
+ * Copyright 2014-2015 Linaro Ltd.
+ */
+
+#include <linux/greybus.h>
+
+static const char *get_descriptor_type_string(u8 type)
+{
+        switch (type) {
+        case GREYBUS_TYPE_INVALID:
+                return "invalid";
+        case GREYBUS_TYPE_STRING:
+                return "string";
+        case GREYBUS_TYPE_INTERFACE:
+                return "interface";
+        case GREYBUS_TYPE_CPORT:
+                return "cport";
+        case GREYBUS_TYPE_BUNDLE:
+                return "bundle";
+        default:
+                WARN_ON(1);
+                return "unknown";
+        }
+}
+
+/*
+ * We scan the manifest once to identify where all the descriptors
+ * are.  The result is a list of these manifest_desc structures.  We
+ * then pick through them for what we're looking for (starting with
+ * the interface descriptor).  As each is processed we remove it from
+ * the list.  When we're done the list should (probably) be empty.
+ */
+struct manifest_desc {
+        struct list_head                links;
+
+        size_t                          size;
+        void                            *data;
+        enum greybus_descriptor_type    type;
+};
+
+static void release_manifest_descriptor(struct manifest_desc *descriptor)
+{
+        list_del(&descriptor->links);
+        kfree(descriptor);
+}
+
+static void release_manifest_descriptors(struct gb_interface *intf)
+{
+        struct manifest_desc *descriptor;
+        struct manifest_desc *next;
+
+        list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links)
+                release_manifest_descriptor(descriptor);
+}
+
+static void release_cport_descriptors(struct list_head *head, u8 bundle_id)
+{
+        struct manifest_desc *desc, *tmp;
+        struct greybus_descriptor_cport *desc_cport;
+
+        list_for_each_entry_safe(desc, tmp, head, links) {
+                desc_cport = desc->data;
+
+                if (desc->type != GREYBUS_TYPE_CPORT)
+                        continue;
+
+                if (desc_cport->bundle == bundle_id)
+                        release_manifest_descriptor(desc);
+        }
+}
+
+static struct manifest_desc *get_next_bundle_desc(struct gb_interface *intf)
+{
+        struct manifest_desc *descriptor;
+        struct manifest_desc *next;
+
+        list_for_each_entry_safe(descriptor, next, &intf->manifest_descs, links)
+                if (descriptor->type == GREYBUS_TYPE_BUNDLE)
+                        return descriptor;
+
+        return NULL;
+}
+
+/*
+ * Validate the given descriptor.  Its reported size must fit within
+ * the number of bytes remaining, and it must have a recognized
+ * type.  Check that the reported size is at least as big as what
+ * we expect to see.  (It could be bigger, perhaps for a new version
+ * of the format.)
+ *
+ * Returns the (non-zero) number of bytes consumed by the descriptor,
+ * or a negative errno.
+ */
+static int identify_descriptor(struct gb_interface *intf,
+                               struct greybus_descriptor *desc, size_t size)
+{
+        struct greybus_descriptor_header *desc_header = &desc->header;
+        struct manifest_desc *descriptor;
+        size_t desc_size;
+        size_t expected_size;
+
+        if (size < sizeof(*desc_header)) {
+                dev_err(&intf->dev, "manifest too small (%zu < %zu)\n", size,
+                        sizeof(*desc_header));
+                return -EINVAL;         /* Must at least have header */
+        }
+
+        desc_size = le16_to_cpu(desc_header->size);
+        if (desc_size > size) {
+                dev_err(&intf->dev, "descriptor too big (%zu > %zu)\n",
+                        desc_size, size);
+                return -EINVAL;
+        }
+
+        /* Descriptor needs to at least have a header */
+        expected_size = sizeof(*desc_header);
+
+        switch (desc_header->type) {
+        case GREYBUS_TYPE_STRING:
+                expected_size += sizeof(struct greybus_descriptor_string);
+                expected_size += desc->string.length;
+
+                /* String descriptors are padded to 4 byte boundaries */
+                expected_size = ALIGN(expected_size, 4);
+                break;
+        case GREYBUS_TYPE_INTERFACE:
+                expected_size += sizeof(struct greybus_descriptor_interface);
+                break;
+        case GREYBUS_TYPE_BUNDLE:
+                expected_size += sizeof(struct greybus_descriptor_bundle);
+                break;
+        case GREYBUS_TYPE_CPORT:
+                expected_size += sizeof(struct greybus_descriptor_cport);
+                break;
+        case GREYBUS_TYPE_INVALID:
+        default:
+                dev_err(&intf->dev, "invalid descriptor type (%u)\n",
+                        desc_header->type);
+                return -EINVAL;
+        }
+
+        if (desc_size < expected_size) {
+                dev_err(&intf->dev, "%s descriptor too small (%zu < %zu)\n",
+                        get_descriptor_type_string(desc_header->type),
+                        desc_size, expected_size);
+                return -EINVAL;
+        }
+
+        /* Descriptor bigger than what we expect */
+        if (desc_size > expected_size) {
+                dev_warn(&intf->dev, "%s descriptor size mismatch (want %zu got %zu)\n",
+                         get_descriptor_type_string(desc_header->type),
+                         expected_size, desc_size);
+        }
+
+        descriptor = kzalloc(sizeof(*descriptor), GFP_KERNEL);
+        if (!descriptor)
+                return -ENOMEM;
+
+        descriptor->size = desc_size;
+        descriptor->data = (char *)desc + sizeof(*desc_header);
+        descriptor->type = desc_header->type;
+        list_add_tail(&descriptor->links, &intf->manifest_descs);
+
+        /* desc_size is positive and is known to fit in a signed int */
+
+        return desc_size;
+}
+
+/*
+ * Find the string descriptor having the given id, validate it, and
+ * allocate a duplicate copy of it.  The duplicate has an extra byte
+ * which guarantees the returned string is NUL-terminated.
+ *
+ * String index 0 is valid (it represents "no string"), and for
+ * that a null pointer is returned.
+ *
+ * Otherwise returns a pointer to a newly-allocated copy of the
+ * descriptor string, or an error-coded pointer on failure.
+ */
+static char *gb_string_get(struct gb_interface *intf, u8 string_id)
+{
+        struct greybus_descriptor_string *desc_string;
+        struct manifest_desc *descriptor;
+        bool found = false;
+        char *string;
+
+        /* A zero string id means no string (but no error) */
+        if (!string_id)
+                return NULL;
+
+        list_for_each_entry(descriptor, &intf->manifest_descs, links) {
+                if (descriptor->type != GREYBUS_TYPE_STRING)
+                        continue;
+
+                desc_string = descriptor->data;
+                if (desc_string->id == string_id) {
+                        found = true;
+                        break;
+                }
+        }
+        if (!found)
+                return ERR_PTR(-ENOENT);
+
+        /* Allocate an extra byte so we can guarantee it's NUL-terminated */
+        string = kmemdup(&desc_string->string, desc_string->length + 1,
+                         GFP_KERNEL);
+        if (!string)
+                return ERR_PTR(-ENOMEM);
+        string[desc_string->length] = '\0';
+
+        /* Ok we've used this string, so we're done with it */
+        release_manifest_descriptor(descriptor);
+
+        return string;
+}
+
+/*
+ * Find cport descriptors in the manifest associated with the given
+ * bundle, and set up data structures for the functions that use
+ * them.  Returns the number of cports set up for the bundle, or 0
+ * if there is an error.
+ */
+static u32 gb_manifest_parse_cports(struct gb_bundle *bundle)
+{
+        struct gb_interface *intf = bundle->intf;
+        struct greybus_descriptor_cport *desc_cport;
+        struct manifest_desc *desc, *next, *tmp;
+        LIST_HEAD(list);
+        u8 bundle_id = bundle->id;
+        u16 cport_id;
+        u32 count = 0;
+        int i;
+
+        /* Set up all cport descriptors associated with this bundle */
+        list_for_each_entry_safe(desc, next, &intf->manifest_descs, links) {
+                if (desc->type != GREYBUS_TYPE_CPORT)
+                        continue;
+
+                desc_cport = desc->data;
+                if (desc_cport->bundle != bundle_id)
+                        continue;
+
+                cport_id = le16_to_cpu(desc_cport->id);
+                if (cport_id > CPORT_ID_MAX)
+                        goto exit;
+
+                /* Nothing else should have its cport_id as control cport id */
+                if (cport_id == GB_CONTROL_CPORT_ID) {
+                        dev_err(&bundle->dev, "invalid cport id found (%02u)\n",
+                                cport_id);
+                        goto exit;
+                }
+
+                /*
+                 * Found one, move it to our temporary list after checking for
+                 * duplicates.
+                 */
+                list_for_each_entry(tmp, &list, links) {
+                        desc_cport = tmp->data;
+                        if (cport_id == le16_to_cpu(desc_cport->id)) {
+                                dev_err(&bundle->dev,
+                                        "duplicate CPort %u found\n", cport_id);
+                                goto exit;
+                        }
+                }
+                list_move_tail(&desc->links, &list);
+                count++;
+        }
+
+        if (!count)
+                return 0;
+
+        bundle->cport_desc = kcalloc(count, sizeof(*bundle->cport_desc),
+                                     GFP_KERNEL);
+        if (!bundle->cport_desc)
+                goto exit;
+
+        bundle->num_cports = count;
+
+        i = 0;
+        list_for_each_entry_safe(desc, next, &list, links) {
+                desc_cport = desc->data;
+                memcpy(&bundle->cport_desc[i++], desc_cport,
+                       sizeof(*desc_cport));
+
+                /* Release the cport descriptor */
+                release_manifest_descriptor(desc);
+        }
+
+        return count;
+exit:
+        release_cport_descriptors(&list, bundle_id);
+        /*
+         * Free all cports for this bundle to avoid 'excess descriptors'
+         * warnings.
+         */
+        release_cport_descriptors(&intf->manifest_descs, bundle_id);
+
+        return 0;       /* Error; count should also be 0 */
+}
+
+/*
+ * Find bundle descriptors in the manifest and set up their data
+ * structures.  Returns the number of bundles set up for the
+ * given interface.
+ */
+static u32 gb_manifest_parse_bundles(struct gb_interface *intf)
+{
+        struct manifest_desc *desc;
+        struct gb_bundle *bundle;
+        struct gb_bundle *bundle_next;
+        u32 count = 0;
+        u8 bundle_id;
+        u8 class;
+
+        while ((desc = get_next_bundle_desc(intf))) {
+                struct greybus_descriptor_bundle *desc_bundle;
+
+                /* Found one.  Set up its bundle structure*/
+                desc_bundle = desc->data;
+                bundle_id = desc_bundle->id;
+                class = desc_bundle->class;
+
+                /* Done with this bundle descriptor */
+                release_manifest_descriptor(desc);
+
+                /* Ignore any legacy control bundles */
+                if (bundle_id == GB_CONTROL_BUNDLE_ID) {
+                        dev_dbg(&intf->dev, "%s - ignoring control bundle\n",
+                                __func__);
+                        release_cport_descriptors(&intf->manifest_descs,
+                                                  bundle_id);
+                        continue;
+                }
+
+                /* Nothing else should have its class set to control class */
+                if (class == GREYBUS_CLASS_CONTROL) {
+                        dev_err(&intf->dev,
+                                "bundle %u cannot use control class\n",
+                                bundle_id);
+                        goto cleanup;
+                }
+
+                bundle = gb_bundle_create(intf, bundle_id, class);
+                if (!bundle)
+                        goto cleanup;
+
+                /*
+                 * Now go set up this bundle's functions and cports.
+                 *
+                 * A 'bundle' represents a device in greybus. It may require
+                 * multiple cports for its functioning. If we fail to setup any
+                 * cport of a bundle, we better reject the complete bundle as
+                 * the device may not be able to function properly then.
+                 *
+                 * But, failing to setup a cport of bundle X doesn't mean that
+                 * the device corresponding to bundle Y will not work properly.
+                 * Bundles should be treated as separate independent devices.
+                 *
+                 * While parsing manifest for an interface, treat bundles as
+                 * separate entities and don't reject entire interface and its
+                 * bundles on failing to initialize a cport. But make sure the
+                 * bundle which needs the cport, gets destroyed properly.
+                 */
+                if (!gb_manifest_parse_cports(bundle)) {
+                        gb_bundle_destroy(bundle);
+                        continue;
+                }
+
+                count++;
+        }
+
+        return count;
+cleanup:
+        /* An error occurred; undo any changes we've made */
+        list_for_each_entry_safe(bundle, bundle_next, &intf->bundles, links) {
+                gb_bundle_destroy(bundle);
+                count--;
+        }
+        return 0;       /* Error; count should also be 0 */
+}
+
+static bool gb_manifest_parse_interface(struct gb_interface *intf,
+                                        struct manifest_desc *interface_desc)
+{
+        struct greybus_descriptor_interface *desc_intf = interface_desc->data;
+        struct gb_control *control = intf->control;
+        char *str;
+
+        /* Handle the strings first--they can fail */
+        str = gb_string_get(intf, desc_intf->vendor_stringid);
+        if (IS_ERR(str))
+                return false;
+        control->vendor_string = str;
+
+        str = gb_string_get(intf, desc_intf->product_stringid);
+        if (IS_ERR(str))
+                goto out_free_vendor_string;
+        control->product_string = str;
+
+        /* Assign feature flags communicated via manifest */
+        intf->features = desc_intf->features;
+
+        /* Release the interface descriptor, now that we're done with it */
+        release_manifest_descriptor(interface_desc);
+
+        /* An interface must have at least one bundle descriptor */
+        if (!gb_manifest_parse_bundles(intf)) {
+                dev_err(&intf->dev, "manifest bundle descriptors not valid\n");
+                goto out_err;
+        }
+
+        return true;
+out_err:
+        kfree(control->product_string);
+        control->product_string = NULL;
+out_free_vendor_string:
+        kfree(control->vendor_string);
+        control->vendor_string = NULL;
+
+        return false;
+}
+
+/*
+ * Parse a buffer containing an interface manifest.
+ *
+ * If we find anything wrong with the content/format of the buffer
+ * we reject it.
+ *
+ * The first requirement is that the manifest's version is
+ * one we can parse.
+ *
+ * We make an initial pass through the buffer and identify all of
+ * the descriptors it contains, keeping track for each its type
+ * and the location size of its data in the buffer.
+ *
+ * Next we scan the descriptors, looking for an interface descriptor;
+ * there must be exactly one of those.  When found, we record the
+ * information it contains, and then remove that descriptor (and any
+ * string descriptors it refers to) from further consideration.
+ *
+ * After that we look for the interface's bundles--there must be at
+ * least one of those.
+ *
+ * Returns true if parsing was successful, false otherwise.
+ */
+bool gb_manifest_parse(struct gb_interface *intf, void *data, size_t size)
+{
+        struct greybus_manifest *manifest;
+        struct greybus_manifest_header *header;
+        struct greybus_descriptor *desc;
+        struct manifest_desc *descriptor;
+        struct manifest_desc *interface_desc = NULL;
+        u16 manifest_size;
+        u32 found = 0;
+        bool result;
+
+        /* Manifest descriptor list should be empty here */
+        if (WARN_ON(!list_empty(&intf->manifest_descs)))
+                return false;
+
+        /* we have to have at _least_ the manifest header */
+        if (size < sizeof(*header)) {
+                dev_err(&intf->dev, "short manifest (%zu < %zu)\n",
+                        size, sizeof(*header));
+                return false;
+        }
+
+        /* Make sure the size is right */
+        manifest = data;
+        header = &manifest->header;
+        manifest_size = le16_to_cpu(header->size);
+        if (manifest_size != size) {
+                dev_err(&intf->dev, "manifest size mismatch (%zu != %u)\n",
+                        size, manifest_size);
+                return false;
+        }
+
+        /* Validate major/minor number */
+        if (header->version_major > GREYBUS_VERSION_MAJOR) {
+                dev_err(&intf->dev, "manifest version too new (%u.%u > %u.%u)\n",
+                        header->version_major, header->version_minor,
+                        GREYBUS_VERSION_MAJOR, GREYBUS_VERSION_MINOR);
+                return false;
+        }
+
+        /* OK, find all the descriptors */
+        desc = manifest->descriptors;
+        size -= sizeof(*header);
+        while (size) {
+                int desc_size;
+
+                desc_size = identify_descriptor(intf, desc, size);
+                if (desc_size < 0) {
+                        result = false;
+                        goto out;
+                }
+                desc = (struct greybus_descriptor *)((char *)desc + desc_size);
+                size -= desc_size;
+        }
+
+        /* There must be a single interface descriptor */
+        list_for_each_entry(descriptor, &intf->manifest_descs, links) {
+                if (descriptor->type == GREYBUS_TYPE_INTERFACE)
+                        if (!found++)
+                                interface_desc = descriptor;
+        }
+        if (found != 1) {
+                dev_err(&intf->dev, "manifest must have 1 interface descriptor (%u found)\n",
+                        found);
+                result = false;
+                goto out;
+        }
+
+        /* Parse the manifest, starting with the interface descriptor */
+        result = gb_manifest_parse_interface(intf, interface_desc);
+
+        /*
+         * We really should have no remaining descriptors, but we
+         * don't know what newer format manifests might leave.
+         */
+        if (result && !list_empty(&intf->manifest_descs))
+                dev_info(&intf->dev, "excess descriptors in interface manifest\n");
+out:
+        release_manifest_descriptors(intf);
+
+        return result;
+}