HID: uhid: Add UHID_CREATE2 + UHID_INPUT2

UHID_CREATE2: HID report descriptor data (rd_data) is an array in struct uhid_create2_req, instead of a pointer. Enables use from languages that don't support pointers, e.g. Python. UHID_INPUT2: Data array is the last field of struct uhid_input2_req. Enables userspace to write only the required bytes to kernel (ev.type + ev.u.input2.size + the part of the data array that matters), instead of the entire struct uhid_input2_req. Note: UHID_CREATE2 increases the total size of struct uhid_event slightly, thus increasing the size of messages that are queued for userspace. However, this won't affect the userspace processing of these events. [Jiri Kosina <jkosina@suse.cz>: adjust to hid_get_raw_report() and hid_output_raw_report() API changes] Signed-off-by: Petri Gynther <pgynther@google.com> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>

HID: uhid: Add UHID_CREATE2 + UHID_INPUT2
UHID_CREATE2: HID report descriptor data (rd_data) is an array in struct uhid_create2_req, instead of a pointer. Enables use from languages that don't support pointers, e.g. Python. UHID_INPUT2: Data array is the last field of struct uhid_input2_req. Enables userspace to write only the required bytes to kernel (ev.type + ev.u.input2.size + the part of the data array that matters), instead of the entire struct uhid_input2_req. Note: UHID_CREATE2 increases the total size of struct uhid_event slightly, thus increasing the size of messages that are queued for userspace. However, this won't affect the userspace processing of these events. [Jiri Kosina <jkosina@suse.cz>: adjust to hid_get_raw_report() and hid_output_raw_report() API changes] Signed-off-by: Petri Gynther <pgynther@google.com> Reviewed-by: David Herrmann <dh.herrmann@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Petri Gynther · Jiri Kosina
1 parent c3d77fab51
Showing 3 changed files with 112 additions and 0 deletions Side-by-side Diff
Documentation/hid/uhid.txt
drivers/hid/uhid.c
include/uapi/linux/uhid.h
@@ -93,6 +93,11 @@
   event to the kernel. The payload is of type struct uhid_create_req and
   contains information about your device. You can start I/O now.
  
+  UHID_CREATE2:
+  Same as UHID_CREATE, but the HID report descriptor data (rd_data) is an array
+  inside struct uhid_create2_req, instead of a pointer to a separate array.
+  Enables use from languages that don't support pointers, e.g. Python.
+
   UHID_DESTROY:
   This destroys the internal HID device. No further I/O will be accepted. There
   may still be pending messages that you can receive with read() but no further
@@ -104,6 +109,12 @@
   You must send UHID_CREATE before sending input to the kernel! This event
   contains a data-payload. This is the raw data that you read from your device.
   The kernel will parse the HID reports and react on it.
+
+  UHID_INPUT2:
+  Same as UHID_INPUT, but the data array is the last field of uhid_input2_req.
+  Enables userspace to write only the required bytes to kernel (ev.type +
+  ev.u.input2.size + the part of the data array that matters), instead of
+  the entire struct uhid_input2_req.
  
   UHID_FEATURE_ANSWER:
   If you receive a UHID_FEATURE request you must answer with this request. You
@@ -428,6 +428,67 @@
 	return ret;
 }
  
+static int uhid_dev_create2(struct uhid_device *uhid,
+			    const struct uhid_event *ev)
+{
+	struct hid_device *hid;
+	int ret;
+
+	if (uhid->running)
+		return -EALREADY;
+
+	uhid->rd_size = ev->u.create2.rd_size;
+	if (uhid->rd_size <= 0 || uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
+		return -EINVAL;
+
+	uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
+	if (!uhid->rd_data)
+		return -ENOMEM;
+
+	memcpy(uhid->rd_data, ev->u.create2.rd_data, uhid->rd_size);
+
+	hid = hid_allocate_device();
+	if (IS_ERR(hid)) {
+		ret = PTR_ERR(hid);
+		goto err_free;
+	}
+
+	strncpy(hid->name, ev->u.create2.name, 127);
+	hid->name[127] = 0;
+	strncpy(hid->phys, ev->u.create2.phys, 63);
+	hid->phys[63] = 0;
+	strncpy(hid->uniq, ev->u.create2.uniq, 63);
+	hid->uniq[63] = 0;
+
+	hid->ll_driver = &uhid_hid_driver;
+	hid->bus = ev->u.create2.bus;
+	hid->vendor = ev->u.create2.vendor;
+	hid->product = ev->u.create2.product;
+	hid->version = ev->u.create2.version;
+	hid->country = ev->u.create2.country;
+	hid->driver_data = uhid;
+	hid->dev.parent = uhid_misc.this_device;
+
+	uhid->hid = hid;
+	uhid->running = true;
+
+	ret = hid_add_device(hid);
+	if (ret) {
+		hid_err(hid, "Cannot register HID device\n");
+		goto err_hid;
+	}
+
+	return 0;
+
+err_hid:
+	hid_destroy_device(hid);
+	uhid->hid = NULL;
+	uhid->running = false;
+err_free:
+	kfree(uhid->rd_data);
+	return ret;
+}
+
 static int uhid_dev_destroy(struct uhid_device *uhid)
 {
 	if (!uhid->running)
@@ -456,6 +517,17 @@
 	return 0;
 }
  
+static int uhid_dev_input2(struct uhid_device *uhid, struct uhid_event *ev)
+{
+	if (!uhid->running)
+		return -EINVAL;
+
+	hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
+			 min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
+
+	return 0;
+}
+
 static int uhid_dev_feature_answer(struct uhid_device *uhid,
 				   struct uhid_event *ev)
 {
  
@@ -592,11 +664,17 @@
 	case UHID_CREATE:
 		ret = uhid_dev_create(uhid, &uhid->input_buf);
 		break;
+	case UHID_CREATE2:
+		ret = uhid_dev_create2(uhid, &uhid->input_buf);
+		break;
 	case UHID_DESTROY:
 		ret = uhid_dev_destroy(uhid);
 		break;
 	case UHID_INPUT:
 		ret = uhid_dev_input(uhid, &uhid->input_buf);
+		break;
+	case UHID_INPUT2:
+		ret = uhid_dev_input2(uhid, &uhid->input_buf);
 		break;
 	case UHID_FEATURE_ANSWER:
 		ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
@@ -21,6 +21,7 @@
  
 #include <linux/input.h>
 #include <linux/types.h>
+#include <linux/hid.h>
  
 enum uhid_event_type {
 	UHID_CREATE,
@@ -34,6 +35,8 @@
 	UHID_INPUT,
 	UHID_FEATURE,
 	UHID_FEATURE_ANSWER,
+	UHID_CREATE2,
+	UHID_INPUT2,
 };
  
 struct uhid_create_req {
@@ -50,6 +53,19 @@
 	__u32 country;
 } __attribute__((__packed__));
  
+struct uhid_create2_req {
+	__u8 name[128];
+	__u8 phys[64];
+	__u8 uniq[64];
+	__u16 rd_size;
+	__u16 bus;
+	__u32 vendor;
+	__u32 product;
+	__u32 version;
+	__u32 country;
+	__u8 rd_data[HID_MAX_DESCRIPTOR_SIZE];
+} __attribute__((__packed__));
+
 #define UHID_DATA_MAX 4096
  
 enum uhid_report_type {
@@ -63,6 +79,11 @@
 	__u16 size;
 } __attribute__((__packed__));
  
+struct uhid_input2_req {
+	__u16 size;
+	__u8 data[UHID_DATA_MAX];
+} __attribute__((__packed__));
+
 struct uhid_output_req {
 	__u8 data[UHID_DATA_MAX];
 	__u16 size;
@@ -100,6 +121,8 @@
 		struct uhid_output_ev_req output_ev;
 		struct uhid_feature_req feature;
 		struct uhid_feature_answer_req feature_answer;
+		struct uhid_create2_req create2;
+		struct uhid_input2_req input2;
 	} u;
 } __attribute__((__packed__));
...	...	@@ -93,6 +93,11 @@
93	93	event to the kernel. The payload is of type struct uhid_create_req and
94	94	contains information about your device. You can start I/O now.
95	95
	96	+ UHID_CREATE2:
	97	+ Same as UHID_CREATE, but the HID report descriptor data (rd_data) is an array
	98	+ inside struct uhid_create2_req, instead of a pointer to a separate array.
	99	+ Enables use from languages that don't support pointers, e.g. Python.
	100	+
96	101	UHID_DESTROY:
97	102	This destroys the internal HID device. No further I/O will be accepted. There
98	103	may still be pending messages that you can receive with read() but no further
...	...	@@ -104,6 +109,12 @@
104	109	You must send UHID_CREATE before sending input to the kernel! This event
105	110	contains a data-payload. This is the raw data that you read from your device.
106	111	The kernel will parse the HID reports and react on it.
	112	+
	113	+ UHID_INPUT2:
	114	+ Same as UHID_INPUT, but the data array is the last field of uhid_input2_req.
	115	+ Enables userspace to write only the required bytes to kernel (ev.type +
	116	+ ev.u.input2.size + the part of the data array that matters), instead of
	117	+ the entire struct uhid_input2_req.
107	118
108	119	UHID_FEATURE_ANSWER:
109	120	If you receive a UHID_FEATURE request you must answer with this request. You
...	...	@@ -428,6 +428,67 @@
428	428	return ret;
429	429	}
430	430
	431	+static int uhid_dev_create2(struct uhid_device *uhid,
	432	+ const struct uhid_event *ev)
	433	+{
	434	+ struct hid_device *hid;
	435	+ int ret;
	436	+
	437	+ if (uhid->running)
	438	+ return -EALREADY;
	439	+
	440	+ uhid->rd_size = ev->u.create2.rd_size;
	441	+ if (uhid->rd_size <= 0 \|\| uhid->rd_size > HID_MAX_DESCRIPTOR_SIZE)
	442	+ return -EINVAL;
	443	+
	444	+ uhid->rd_data = kmalloc(uhid->rd_size, GFP_KERNEL);
	445	+ if (!uhid->rd_data)
	446	+ return -ENOMEM;
	447	+
	448	+ memcpy(uhid->rd_data, ev->u.create2.rd_data, uhid->rd_size);
	449	+
	450	+ hid = hid_allocate_device();
	451	+ if (IS_ERR(hid)) {
	452	+ ret = PTR_ERR(hid);
	453	+ goto err_free;
	454	+ }
	455	+
	456	+ strncpy(hid->name, ev->u.create2.name, 127);
	457	+ hid->name[127] = 0;
	458	+ strncpy(hid->phys, ev->u.create2.phys, 63);
	459	+ hid->phys[63] = 0;
	460	+ strncpy(hid->uniq, ev->u.create2.uniq, 63);
	461	+ hid->uniq[63] = 0;
	462	+
	463	+ hid->ll_driver = &uhid_hid_driver;
	464	+ hid->bus = ev->u.create2.bus;
	465	+ hid->vendor = ev->u.create2.vendor;
	466	+ hid->product = ev->u.create2.product;
	467	+ hid->version = ev->u.create2.version;
	468	+ hid->country = ev->u.create2.country;
	469	+ hid->driver_data = uhid;
	470	+ hid->dev.parent = uhid_misc.this_device;
	471	+
	472	+ uhid->hid = hid;
	473	+ uhid->running = true;
	474	+
	475	+ ret = hid_add_device(hid);
	476	+ if (ret) {
	477	+ hid_err(hid, "Cannot register HID device\n");
	478	+ goto err_hid;
	479	+ }
	480	+
	481	+ return 0;
	482	+
	483	+err_hid:
	484	+ hid_destroy_device(hid);
	485	+ uhid->hid = NULL;
	486	+ uhid->running = false;
	487	+err_free:
	488	+ kfree(uhid->rd_data);
	489	+ return ret;
	490	+}
	491	+
431	492	static int uhid_dev_destroy(struct uhid_device *uhid)
432	493	{
433	494	if (!uhid->running)
...	...	@@ -456,6 +517,17 @@
456	517	return 0;
457	518	}
458	519
	520	+static int uhid_dev_input2(struct uhid_device uhid, struct uhid_event ev)
	521	+{
	522	+ if (!uhid->running)
	523	+ return -EINVAL;
	524	+
	525	+ hid_input_report(uhid->hid, HID_INPUT_REPORT, ev->u.input2.data,
	526	+ min_t(size_t, ev->u.input2.size, UHID_DATA_MAX), 0);
	527	+
	528	+ return 0;
	529	+}
	530	+
459	531	static int uhid_dev_feature_answer(struct uhid_device *uhid,
460	532	struct uhid_event *ev)
461	533	{
462	534
...	...	@@ -592,11 +664,17 @@
592	664	case UHID_CREATE:
593	665	ret = uhid_dev_create(uhid, &uhid->input_buf);
594	666	break;
	667	+ case UHID_CREATE2:
	668	+ ret = uhid_dev_create2(uhid, &uhid->input_buf);
	669	+ break;
595	670	case UHID_DESTROY:
596	671	ret = uhid_dev_destroy(uhid);
597	672	break;
598	673	case UHID_INPUT:
599	674	ret = uhid_dev_input(uhid, &uhid->input_buf);
	675	+ break;
	676	+ case UHID_INPUT2:
	677	+ ret = uhid_dev_input2(uhid, &uhid->input_buf);
600	678	break;
601	679	case UHID_FEATURE_ANSWER:
602	680	ret = uhid_dev_feature_answer(uhid, &uhid->input_buf);
...	...	@@ -21,6 +21,7 @@
21	21
22	22	#include <linux/input.h>
23	23	#include <linux/types.h>
	24	+#include <linux/hid.h>
24	25
25	26	enum uhid_event_type {
26	27	UHID_CREATE,
...	...	@@ -34,6 +35,8 @@
34	35	UHID_INPUT,
35	36	UHID_FEATURE,
36	37	UHID_FEATURE_ANSWER,
	38	+ UHID_CREATE2,
	39	+ UHID_INPUT2,
37	40	};
38	41
39	42	struct uhid_create_req {
...	...	@@ -50,6 +53,19 @@
50	53	__u32 country;
51	54	} __attribute__((__packed__));
52	55
	56	+struct uhid_create2_req {
	57	+ __u8 name[128];
	58	+ __u8 phys[64];
	59	+ __u8 uniq[64];
	60	+ __u16 rd_size;
	61	+ __u16 bus;
	62	+ __u32 vendor;
	63	+ __u32 product;
	64	+ __u32 version;
	65	+ __u32 country;
	66	+ __u8 rd_data[HID_MAX_DESCRIPTOR_SIZE];
	67	+} __attribute__((__packed__));
	68	+
53	69	#define UHID_DATA_MAX 4096
54	70
55	71	enum uhid_report_type {
...	...	@@ -63,6 +79,11 @@
63	79	__u16 size;
64	80	} __attribute__((__packed__));
65	81
	82	+struct uhid_input2_req {
	83	+ __u16 size;
	84	+ __u8 data[UHID_DATA_MAX];
	85	+} __attribute__((__packed__));
	86	+
66	87	struct uhid_output_req {
67	88	__u8 data[UHID_DATA_MAX];
68	89	__u16 size;
...	...	@@ -100,6 +121,8 @@
100	121	struct uhid_output_ev_req output_ev;
101	122	struct uhid_feature_req feature;
102	123	struct uhid_feature_answer_req feature_answer;
	124	+ struct uhid_create2_req create2;
	125	+ struct uhid_input2_req input2;
103	126	} u;
104	127	} __attribute__((__packed__));
105	128