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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>
This commit is contained in:
Benjamin Tissoires 2013-08-22 14:51:07 +02:00 committed by Jiri Kosina
parent c08d46aa80
commit 3dc8fc083d
1 changed files with 64 additions and 38 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

102
drivers/hid/hid-core.c
View File

@ -677,12 +677,52 @@ static u8 *fetch_item(__u8 *start, __u8 *end, struct hid_item *item)
return NULL;
}
static void hid_scan_usage(struct hid_device *hid, u32 usage)
static void hid_scan_input_usage(struct hid_parser *parser, u32 usage)
{
struct hid_device *hid = parser->device;
if (usage == HID_DG_CONTACTID)
hid->group = HID_GROUP_MULTITOUCH;
}
static void hid_scan_collection(struct hid_parser *parser, unsigned type)
{
struct hid_device *hid = parser->device;
if (((parser->global.usage_page << 16) == HID_UP_SENSOR) &&
type == HID_COLLECTION_PHYSICAL)
hid->group = HID_GROUP_SENSOR_HUB;
}
static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
{
__u32 data;
int i;
data = item_udata(item);
switch (item->tag) {
case HID_MAIN_ITEM_TAG_BEGIN_COLLECTION:
hid_scan_collection(parser, data & 0xff);
break;
case HID_MAIN_ITEM_TAG_END_COLLECTION:
break;
case HID_MAIN_ITEM_TAG_INPUT:
for (i = 0; i < parser->local.usage_index; i++)
hid_scan_input_usage(parser, parser->local.usage[i]);
break;
case HID_MAIN_ITEM_TAG_OUTPUT:
break;
case HID_MAIN_ITEM_TAG_FEATURE:
break;
}
/* Reset the local parser environment */
memset(&parser->local, 0, sizeof(parser->local));
return 0;
}
/*
* Scan a report descriptor before the device is added to the bus.
* Sets device groups and other properties that determine what driver
@ -690,48 +730,34 @@ static void hid_scan_usage(struct hid_device *hid, u32 usage)
*/
static int hid_scan_report(struct hid_device *hid)
{
unsigned int page = 0, delim = 0;
struct hid_parser *parser;
struct hid_item item;
__u8 *start = hid->dev_rdesc;
__u8 *end = start + hid->dev_rsize;
unsigned int u, u_min = 0, u_max = 0;
struct hid_item item;
static int (*dispatch_type[])(struct hid_parser *parser,
struct hid_item *item) = {
hid_scan_main,
hid_parser_global,
hid_parser_local,
hid_parser_reserved
};
parser = vzalloc(sizeof(struct hid_parser));
if (!parser)
return -ENOMEM;
parser->device = hid;
hid->group = HID_GROUP_GENERIC;
while ((start = fetch_item(start, end, &item)) != NULL) {
if (item.format != HID_ITEM_FORMAT_SHORT)
return -EINVAL;
if (item.type == HID_ITEM_TYPE_GLOBAL) {
if (item.tag == HID_GLOBAL_ITEM_TAG_USAGE_PAGE)
page = item_udata(&item) << 16;
} else if (item.type == HID_ITEM_TYPE_LOCAL) {
if (delim > 1)
break;
u = item_udata(&item);
if (item.size <= 2)
u += page;
switch (item.tag) {
case HID_LOCAL_ITEM_TAG_DELIMITER:
delim += !!u;
break;
case HID_LOCAL_ITEM_TAG_USAGE:
hid_scan_usage(hid, u);
break;
case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
u_min = u;
break;
case HID_LOCAL_ITEM_TAG_USAGE_MAXIMUM:
u_max = u;
for (u = u_min; u <= u_max; u++)
hid_scan_usage(hid, u);
break;
}
} else if (page == HID_UP_SENSOR &&
item.type == HID_ITEM_TYPE_MAIN &&
item.tag == HID_MAIN_ITEM_TAG_BEGIN_COLLECTION &&
(item_udata(&item) & 0xff) == HID_COLLECTION_PHYSICAL)
hid->group = HID_GROUP_SENSOR_HUB;
}
/*
* The parsing is simpler than the one in hid_open_report() as we should
* be robust against hid errors. Those errors will be raised by
* hid_open_report() anyway.
*/
while ((start = fetch_item(start, end, &item)) != NULL)
dispatch_type[item.type](parser, &item);
vfree(parser);
return 0;
}