HID: Use hid_parser for pre-scanning the report descriptors
The Win 8 detection is sufficiently complex to warrant use of the full parser code, in spite of the inferred memory usage. Therefore, we can use the existing HID parser in hid-core for hid_scan_report() by re-using the code from hid_open_report(). hid_parser_global, hid_parser_local and hid_parser_reserved does not have any side effects. We just need to reimplement the MAIN_ITEM callback to have a proper parsing without side effects. Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com> Reviewed-by: Henrik Rydberg <rydberg@euromail.se> Tested-by: Srinivas Pandruvada<srinivas.pandruvada@linux.intel.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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@ -677,12 +677,52 @@ static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
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return NULL;
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}
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static void hid_scan_usage(struct hid_device *hid, u32 usage)
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static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
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{
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struct hid_device *hid = parser->device;
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if (usage == HID_DG_CONTACTID)
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hid->group = HID_GROUP_MULTITOUCH;
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}
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static void hid_scan_collection(struct hid_parser *parser, unsigned type)
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{
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struct hid_device *hid = parser->device;
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if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
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type == HID_COLLECTION_PHYSICAL)
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hid->group = HID_GROUP_SENSOR_HUB;
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}
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static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
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{
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__u32 data;
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int i;
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data = item_udata(item);
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switch (item->tag) {
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case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
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hid_scan_collection(parser, data & 0xff);
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break;
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case HID_MAIN_ITEM_TAG_END_COLLECTION:
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break;
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case HID_MAIN_ITEM_TAG_INPUT:
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for (i = 0; i < parser->local.usage_index; i++)
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hid_scan_input_usage(parser, parser->local.usage[i]);
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break;
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case HID_MAIN_ITEM_TAG_OUTPUT:
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break;
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case HID_MAIN_ITEM_TAG_FEATURE:
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break;
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}
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/* Reset the local parser environment */
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memset(&parser->local, 0, sizeof(parser->local));
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return 0;
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}
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/*
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* Scan a report descriptor before the device is added to the bus.
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* Sets device groups and other properties that determine what driver
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@ -690,48 +730,34 @@ static void hid_scan_usage(struct hid_device *hid, u32 usage)
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*/
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static int hid_scan_report(struct hid_device *hid)
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{
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unsigned int page = 0, delim = 0;
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struct hid_parser *parser;
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struct hid_item item;
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__u8 *start = hid->dev_rdesc;
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__u8 *end = start + hid->dev_rsize;
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unsigned int u, u_min = 0, u_max = 0;
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struct hid_item item;
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static int (*dispatch_type[])(struct hid_parser *parser,
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struct hid_item *item) = {
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hid_scan_main,
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hid_parser_global,
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hid_parser_local,
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hid_parser_reserved
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};
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parser = vzalloc(sizeof(struct hid_parser));
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if (!parser)
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return -ENOMEM;
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parser->device = hid;
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hid->group = HID_GROUP_GENERIC;
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while ((start = fetch_item(start, end, &item)) != NULL) {
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if (item.format != HID_ITEM_FORMAT_SHORT)
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return -EINVAL;
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if (item.type == HID_ITEM_TYPE_GLOBAL) {
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if (item.tag == HID_GLOBAL_ITEM_TAG_USAGE_PAGE)
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page = item_udata(&item) << 16;
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} else if (item.type == HID_ITEM_TYPE_LOCAL) {
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if (delim > 1)
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break;
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u = item_udata(&item);
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if (item.size <= 2)
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u += page;
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switch (item.tag) {
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case HID_LOCAL_ITEM_TAG_DELIMITER:
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delim += !!u;
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break;
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case HID_LOCAL_ITEM_TAG_USAGE:
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hid_scan_usage(hid, u);
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break;
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case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
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u_min = u;
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break;
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case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
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u_max = u;
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for (u = u_min; u <= u_max; u++)
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hid_scan_usage(hid, u);
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break;
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}
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} else if (page == HID_UP_SENSOR &&
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item.type == HID_ITEM_TYPE_MAIN &&
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item.tag == HID_MAIN_ITEM_TAG_BEGIN_COLLECTION &&
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(item_udata(&item) & 0xff) == HID_COLLECTION_PHYSICAL)
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hid->group = HID_GROUP_SENSOR_HUB;
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}
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/*
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* The parsing is simpler than the one in hid_open_report() as we should
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* be robust against hid errors. Those errors will be raised by
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* hid_open_report() anyway.
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*/
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while ((start = fetch_item(start, end, &item)) != NULL)
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dispatch_type[item.type](parser, &item);
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vfree(parser);
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return 0;
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}
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