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>

diff --git a/Documentation/hid/uhid.txt b/Documentation/hid/uhid.txt
index dc35a2b..ee65936 100644 (file)
--- a/Documentation/hid/uhid.txt
+++ b/Documentation/hid/uhid.txt
@@ -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

diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 7ed79be..0d078c3 100644 (file)
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -428,6 +428,67 @@ err_free:
        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;

diff --git a/include/uapi/linux/uhid.h b/include/uapi/linux/uhid.h
index 414b74b..1e3b09c 100644 (file)
--- a/include/uapi/linux/uhid.h
+++ b/include/uapi/linux/uhid.h
@@ -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__));