HID: uhid: implement SET_REPORT

We so far lacked support for hid_hw_raw_request(..., HID_REQ_SET_REPORT);
Add support for it and simply forward the request to user-space. Note that
SET_REPORT is synchronous, just like GET_REPORT, even though it does not
provide any data back besides an error code.

If a transport layer does SET_REPORT asynchronously, they can just ACK it
immediately by writing an uhid_set_report_reply to uhid.

This patch re-uses the synchronous uhid-report infrastructure to query
user-space. Note that this means you cannot run SET_REPORT and GET_REPORT
in parallel. However, that has always been a restriction of HID and due to
its blocking nature, this is just fine. Maybe some future transport layer
supports parallel requests (very unlikely), however, until then lets not
over-complicate things and avoid request-lookup-tables.

Signed-off-by: David Herrmann <dh.herrmann@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/uapi/linux/uhid.h b/include/uapi/linux/uhid.h
index 116536eeae62..62aac0e4edf3 100644
--- a/include/uapi/linux/uhid.h
+++ b/include/uapi/linux/uhid.h
@@ -37,6 +37,8 @@ enum uhid_event_type {
 	UHID_GET_REPORT_REPLY,
 	UHID_CREATE2,
 	UHID_INPUT2,
+	UHID_SET_REPORT,
+	UHID_SET_REPORT_REPLY,
 };
 
 struct uhid_create2_req {
@@ -84,6 +86,19 @@ struct uhid_get_report_reply_req {
 	__u8 data[UHID_DATA_MAX];
 } __attribute__((__packed__));
 
+struct uhid_set_report_req {
+	__u32 id;
+	__u8 rnum;
+	__u8 rtype;
+	__u16 size;
+	__u8 data[UHID_DATA_MAX];
+} __attribute__((__packed__));
+
+struct uhid_set_report_reply_req {
+	__u32 id;
+	__u16 err;
+} __attribute__((__packed__));
+
 /*
  * Compat Layer
  * All these commands and requests are obsolete. You should avoid using them in
@@ -165,6 +180,8 @@ struct uhid_event {
 		struct uhid_get_report_reply_req get_report_reply;
 		struct uhid_create2_req create2;
 		struct uhid_input2_req input2;
+		struct uhid_set_report_req set_report;
+		struct uhid_set_report_reply_req set_report_reply;
 	} u;
 } __attribute__((__packed__));