HID: uhid: add UHID_CREATE and UHID_DESTROY events

UHID_CREATE and UHID_DESTROY are used to create and destroy a device on an
open uhid char-device. Internally, we allocate and register an HID device
with the HID core and immediately start the device. From now on events may
be received or sent to the device.

The UHID_CREATE event has a payload similar to the data used by
Bluetooth-HIDP when creating a new connection.

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

diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c
index 31e8379..61ee7cc 100644 (file)
--- a/drivers/hid/uhid.c
+++ b/drivers/hid/uhid.c
@@ -29,6 +29,11 @@
 
 struct uhid_device {
        struct mutex devlock;
+       bool running;
+
+       __u8 *rd_data;
+       uint rd_size;
+
        struct hid_device *hid;
        struct uhid_event input_buf;
 
@@ -75,6 +80,136 @@ static int uhid_queue_event(struct uhid_device *uhid, __u32 event)
        return 0;
 }
 
+static int uhid_hid_start(struct hid_device *hid)
+{
+       return 0;
+}
+
+static void uhid_hid_stop(struct hid_device *hid)
+{
+}
+
+static int uhid_hid_open(struct hid_device *hid)
+{
+       return 0;
+}
+
+static void uhid_hid_close(struct hid_device *hid)
+{
+}
+
+static int uhid_hid_input(struct input_dev *input, unsigned int type,
+                         unsigned int code, int value)
+{
+       return 0;
+}
+
+static int uhid_hid_parse(struct hid_device *hid)
+{
+       return 0;
+}
+
+static int uhid_hid_get_raw(struct hid_device *hid, unsigned char rnum,
+                           __u8 *buf, size_t count, unsigned char rtype)
+{
+       return 0;
+}
+
+static int uhid_hid_output_raw(struct hid_device *hid, __u8 *buf, size_t count,
+                              unsigned char report_type)
+{
+       return 0;
+}
+
+static struct hid_ll_driver uhid_hid_driver = {
+       .start = uhid_hid_start,
+       .stop = uhid_hid_stop,
+       .open = uhid_hid_open,
+       .close = uhid_hid_close,
+       .hidinput_input_event = uhid_hid_input,
+       .parse = uhid_hid_parse,
+};
+
+static int uhid_dev_create(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.create.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;
+
+       if (copy_from_user(uhid->rd_data, ev->u.create.rd_data,
+                          uhid->rd_size)) {
+               ret = -EFAULT;
+               goto err_free;
+       }
+
+       hid = hid_allocate_device();
+       if (IS_ERR(hid)) {
+               ret = PTR_ERR(hid);
+               goto err_free;
+       }
+
+       strncpy(hid->name, ev->u.create.name, 127);
+       hid->name[127] = 0;
+       strncpy(hid->phys, ev->u.create.phys, 63);
+       hid->phys[63] = 0;
+       strncpy(hid->uniq, ev->u.create.uniq, 63);
+       hid->uniq[63] = 0;
+
+       hid->ll_driver = &uhid_hid_driver;
+       hid->hid_get_raw_report = uhid_hid_get_raw;
+       hid->hid_output_raw_report = uhid_hid_output_raw;
+       hid->bus = ev->u.create.bus;
+       hid->vendor = ev->u.create.vendor;
+       hid->product = ev->u.create.product;
+       hid->version = ev->u.create.version;
+       hid->country = ev->u.create.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)
+               return -EINVAL;
+
+       uhid->running = false;
+
+       hid_destroy_device(uhid->hid);
+       kfree(uhid->rd_data);
+
+       return 0;
+}
+
 static int uhid_char_open(struct inode *inode, struct file *file)
 {
        struct uhid_device *uhid;
@@ -86,6 +221,7 @@ static int uhid_char_open(struct inode *inode, struct file *file)
        mutex_init(&uhid->devlock);
        spin_lock_init(&uhid->qlock);
        init_waitqueue_head(&uhid->waitq);
+       uhid->running = false;
 
        file->private_data = uhid;
        nonseekable_open(inode, file);
@@ -98,6 +234,8 @@ static int uhid_char_release(struct inode *inode, struct file *file)
        struct uhid_device *uhid = file->private_data;
        unsigned int i;
 
+       uhid_dev_destroy(uhid);
+
        for (i = 0; i < UHID_BUFSIZE; ++i)
                kfree(uhid->outq[i]);
 
@@ -177,6 +315,12 @@ static ssize_t uhid_char_write(struct file *file, const char __user *buffer,
        }
 
        switch (uhid->input_buf.type) {
+       case UHID_CREATE:
+               ret = uhid_dev_create(uhid, &uhid->input_buf);
+               break;
+       case UHID_DESTROY:
+               ret = uhid_dev_destroy(uhid);
+               break;
        default:
                ret = -EOPNOTSUPP;
        }

diff --git a/include/linux/uhid.h b/include/linux/uhid.h
index 16b786a..8a493e6 100644 (file)
--- a/include/linux/uhid.h
+++ b/include/linux/uhid.h
@@ -23,11 +23,30 @@
 #include <linux/types.h>
 
 enum uhid_event_type {
-       UHID_DUMMY,
+       UHID_CREATE,
+       UHID_DESTROY,
 };
 
+struct uhid_create_req {
+       __u8 name[128];
+       __u8 phys[64];
+       __u8 uniq[64];
+       __u8 __user *rd_data;
+       __u16 rd_size;
+
+       __u16 bus;
+       __u32 vendor;
+       __u32 product;
+       __u32 version;
+       __u32 country;
+} __attribute__((__packed__));
+
 struct uhid_event {
        __u32 type;
+
+       union {
+               struct uhid_create_req create;
+       } u;
 } __attribute__((__packed__));
 
 #endif /* __UHID_H_ */