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Commit 4522643a authored by Petri Gynther's avatar Petri Gynther Committed by Jiri Kosina
Browse files

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: default avatarPetri Gynther <pgynther@google.com>
Reviewed-by: default avatarDavid Herrmann <dh.herrmann@gmail.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
parent c3d77fab

Documentation/hid/uhid.txt

+11 −0
Original line number Diff line number Diff line
@@ -93,6 +93,11 @@ the request was handled successfully. 
  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
@@ -105,6 +110,12 @@ the request was handled successfully. 
  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

  must copy the "id" field from the request into the answer. Set the "err" field

drivers/hid/uhid.c

+78 −0
Original line number Diff line number Diff line
@@ -428,6 +428,67 @@ static int uhid_dev_create(struct uhid_device *uhid, 
	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 @@ static int uhid_dev_input(struct uhid_device *uhid, struct uhid_event *ev) 
	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)

{
@@ -592,12 +664,18 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer, 
	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);

		break;

include/uapi/linux/uhid.h

+23 −0
Original line number Diff line number Diff line
@@ -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 @@ enum uhid_event_type { 
	UHID_INPUT,

	UHID_FEATURE,

	UHID_FEATURE_ANSWER,

	UHID_CREATE2,

	UHID_INPUT2,

};



struct uhid_create_req {
@@ -50,6 +53,19 @@ struct uhid_create_req { 
	__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 @@ struct uhid_input_req { 
	__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_event { 
		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__));