android-keyboard-gadget.patch

diff --git a/drivers/usb/gadget/android.c b/drivers/usb/gadget/android.c
index 9bc546d..60d9892 100644
--- a/drivers/usb/gadget/android.c
+++ b/drivers/usb/gadget/android.c
@@ -62,6 +62,8 @@
 #include "f_ccid.c"
 #include "f_mtp.c"
 #include "f_accessory.c"
+#include "f_hid_android_keyboard.c"
+#include "f_hid_android_mouse.c"
 #include "f_rndis.c"
 #include "rndis.c"
 #include "f_qc_ecm.c"
@@ -1417,10 +1419,22 @@ static void hid_function_cleanup(struct android_usb_function *f)
 	ghid_cleanup();
 }
 
-static int hid_function_bind_config(struct android_usb_function *f,
-					struct usb_configuration *c)
+static int hid_function_bind_config(struct android_usb_function *f, struct usb_configuration *c)
 {
-	return hidg_bind_config(c, NULL, 0);
+	int ret;
+	printk(KERN_INFO "hid keyboard\n");
+	ret = hidg_bind_config(c, &ghid_device_android_keyboard, 0);
+	if (ret) {
+		pr_info("%s: hid_function_bind_config keyboard failed: %d\n", __func__, ret);
+		return ret;
+	}
+	printk(KERN_INFO "hid mouse\n");
+	ret = hidg_bind_config(c, &ghid_device_android_mouse, 1);
+	if (ret) {
+		pr_info("%s: hid_function_bind_config mouse failed: %d\n", __func__, ret);
+		return ret;
+	}
+	return 0;
 }
 
 static struct android_usb_function hid_function = {
@@ -1954,7 +1968,6 @@ static struct android_usb_function charger_function = {
 	.bind_config	= charger_function_bind_config,
 };
 
-
 static int
 mtp_function_init(struct android_usb_function *f,
 		struct usb_composite_dev *cdev)
@@ -2997,6 +3010,7 @@ static struct android_usb_function usbnet_function = {
 	.ctrlrequest	= usbnet_function_ctrlrequest,
 };
 
+
 static struct android_usb_function *supported_functions[] = {
 	&ffs_function,
 	&mbim_function,
@@ -3387,7 +3401,8 @@ functions_store(struct device *pdev, struct device_attribute *attr,
 							name, err);
 		}
 	}
-
+  /* HID driver always enabled, it's the whole point of this kernel patch */
+  android_enable_function(dev, conf, "hid");
 	/* Free uneeded configurations if exists */
 	while (curr_conf->next != &dev->configs) {
 		conf = list_entry(curr_conf->next,
diff --git a/drivers/usb/gadget/f_hid.c b/drivers/usb/gadget/f_hid.c
index f5ca673..5abd976 100644
--- a/drivers/usb/gadget/f_hid.c
+++ b/drivers/usb/gadget/f_hid.c
@@ -17,6 +17,7 @@
 #include <linux/poll.h>
 #include <linux/uaccess.h>
 #include <linux/wait.h>
+#include <linux/delay.h>
 #include <linux/sched.h>
 #include <linux/usb/g_hid.h>
 
@@ -64,6 +65,43 @@ struct f_hidg {
 	struct usb_ep			*out_ep;
 };
 
+/* Hacky device list to fix f_hidg_write being called after device destroyed.
+   It covers only most common race conditions, there will be rare crashes anyway. */
+enum { HACKY_DEVICE_LIST_SIZE = 4 };
+static struct f_hidg *hacky_device_list[HACKY_DEVICE_LIST_SIZE];
+static void hacky_device_list_add(struct f_hidg *hidg)
+{
+	int i;
+	for (i = 0; i < HACKY_DEVICE_LIST_SIZE; i++) {
+		if (!hacky_device_list[i]) {
+			hacky_device_list[i] = hidg;
+			return;
+		}
+	}
+	pr_err("%s: too many devices, not adding device %p\n", __func__, hidg);
+}
+static void hacky_device_list_remove(struct f_hidg *hidg)
+{
+	int i;
+	for (i = 0; i < HACKY_DEVICE_LIST_SIZE; i++) {
+		if (hacky_device_list[i] == hidg) {
+			hacky_device_list[i] = NULL;
+			return;
+		}
+	}
+	pr_err("%s: cannot find device %p\n", __func__, hidg);
+}
+static int hacky_device_list_check(struct f_hidg *hidg)
+{
+	int i;
+	for (i = 0; i < HACKY_DEVICE_LIST_SIZE; i++) {
+		if (hacky_device_list[i] == hidg) {
+			return 0;
+		}
+	}
+	return 1;
+}
+
 static inline struct f_hidg *func_to_hidg(struct usb_function *f)
 {
 	return container_of(f, struct f_hidg, func);
@@ -199,6 +237,11 @@ static ssize_t f_hidg_read(struct file *file, char __user *buffer,
 	if (!access_ok(VERIFY_WRITE, buffer, count))
 		return -EFAULT;
 
+  if (hacky_device_list_check(hidg)) {
+  	pr_err("%s: trying to read from device %p that was destroyed\n", __func__, hidg);
+  	return -EIO;
+  }
+
 	spin_lock_irqsave(&hidg->spinlock, flags);
 
 #define READ_COND (!list_empty(&hidg->completed_out_req))
@@ -269,6 +312,11 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
 	if (!access_ok(VERIFY_READ, buffer, count))
 		return -EFAULT;
 
+	if (hacky_device_list_check(hidg)) {
+		pr_err("%s: trying to write to device %p that was destroyed\n", __func__, hidg);
+		return -EIO;
+	}
+  
 	mutex_lock(&hidg->lock);
 
 #define WRITE_COND (!hidg->write_pending)
@@ -283,6 +331,11 @@ static ssize_t f_hidg_write(struct file *file, const char __user *buffer,
 				hidg->write_queue, WRITE_COND))
 			return -ERESTARTSYS;
 
+    if (hacky_device_list_check(hidg)) {
+    	pr_err("%s: trying to write to device %p that was destroyed\n", __func__, hidg);
+    	return -EIO;
+    }
+
 		mutex_lock(&hidg->lock);
 	}
 
@@ -322,8 +375,17 @@ static unsigned int f_hidg_poll(struct file *file, poll_table *wait)
 {
 	struct f_hidg	*hidg  = file->private_data;
 	unsigned int	ret = 0;
+  if (hacky_device_list_check(hidg)) {
+  		pr_err("%s: trying to poll device %p that was destroyed\n", __func__, hidg);
+  		return -EIO;
+  }
 
 	poll_wait(file, &hidg->read_queue, wait);
+  if (hacky_device_list_check(hidg)) {
+  		pr_err("%s: trying to poll device %p that was destroyed\n", __func__, hidg);
+  		return -EIO;
+  }
+  
 	poll_wait(file, &hidg->write_queue, wait);
 
 	if (WRITE_COND)
@@ -422,7 +484,12 @@ static int hidg_setup(struct usb_function *f,
 	case ((USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 		  | HID_REQ_GET_PROTOCOL):
 		VDBG(cdev, "get_protocol\n");
-		goto stall;
+    length = min_t(unsigned, length, 1);
+		if (hidg->bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT)
+			((u8 *) req->buf)[0] = 0;	/* Boot protocol */
+		else
+			((u8 *) req->buf)[0] = 1;	/* Report protocol */
+		goto respond;
 		break;
 
 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
@@ -434,6 +501,14 @@ static int hidg_setup(struct usb_function *f,
 	case ((USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE) << 8
 		  | HID_REQ_SET_PROTOCOL):
 		VDBG(cdev, "set_protocol\n");
+		length = 0;
+		if (hidg->bInterfaceSubClass == USB_INTERFACE_SUBCLASS_BOOT) {
+			if (value == 0)		/* Boot protocol */
+				goto respond;
+		} else {
+			if (value == 1)		/* Report protocol */
+				goto respond;
+		}
 		goto stall;
 		break;
 
@@ -589,7 +664,8 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
 	struct f_hidg		*hidg = func_to_hidg(f);
 	int			status;
 	dev_t			dev;
-
+  pr_info("%s: creating device %p\n", __func__, hidg);
+  
 	/* allocate instance-specific interface IDs, and patch descriptors */
 	status = usb_interface_id(c, f);
 	if (status < 0)
@@ -655,7 +731,7 @@ static int hidg_bind(struct usb_configuration *c, struct usb_function *f)
 		goto fail;
 
 	device_create(hidg_class, NULL, dev, NULL, "%s%d", "hidg", hidg->minor);
-
+  hacky_device_list_add(hidg);
 	return 0;
 
 fail:
@@ -674,12 +750,22 @@ static void hidg_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_hidg *hidg = func_to_hidg(f);
 
+  pr_info("%s: destroying device %p\n", __func__, hidg);
+  /* This does not cover all race conditions, only most common one */
+  mutex_lock(&hidg->lock);
+  hacky_device_list_remove(hidg);
+  mutex_unlock(&hidg->lock);
+  
 	device_destroy(hidg_class, MKDEV(major, hidg->minor));
 	cdev_del(&hidg->cdev);
 
 	/* disable/free request and end point */
 	usb_ep_disable(hidg->in_ep);
 	usb_ep_dequeue(hidg->in_ep, hidg->req);
+  /* TODO: calling this function crash kernel,
+     not calling this funct ion crash kernel inside f_hidg_write */
+  /* usb_ep_dequeue(hidg->in_ep, hidg->req); */
+  	
 	kfree(hidg->req->buf);
 	usb_ep_free_request(hidg->in_ep, hidg->req);
 
diff --git a/drivers/usb/gadget/f_hid_android_keyboard.c b/drivers/usb/gadget/f_hid_android_keyboard.c
new file mode 100644
index 0000000..1824bdd
--- /dev/null
+++ b/drivers/usb/gadget/f_hid_android_keyboard.c
@@ -0,0 +1,44 @@
+#include <linux/platform_device.h>
+#include <linux/usb/g_hid.h>
+
+/* hid descriptor for a keyboard */
+static struct hidg_func_descriptor ghid_device_android_keyboard = {
+	.subclass		= 1, /* Boot Interface Subclass */
+	.protocol		= 1, /* Keyboard */
+	.report_length		= 8,
+	.report_desc_length	= 63,
+	.report_desc		= {
+		0x05, 0x01,	/* USAGE_PAGE (Generic Desktop)	          */
+		0x09, 0x06,	/* USAGE (Keyboard)                       */
+		0xa1, 0x01,	/* COLLECTION (Application)               */
+		0x05, 0x07,	/*   USAGE_PAGE (Keyboard)                */
+		0x19, 0xe0,	/*   USAGE_MINIMUM (Keyboard LeftControl) */
+		0x29, 0xe7,	/*   USAGE_MAXIMUM (Keyboard Right GUI)   */
+		0x15, 0x00,	/*   LOGICAL_MINIMUM (0)                  */
+		0x25, 0x01,	/*   LOGICAL_MAXIMUM (1)                  */
+		0x75, 0x01,	/*   REPORT_SIZE (1)                      */
+		0x95, 0x08,	/*   REPORT_COUNT (8)                     */
+		0x81, 0x02,	/*   INPUT (Data,Var,Abs)                 */
+		0x95, 0x01,	/*   REPORT_COUNT (1)                     */
+		0x75, 0x08,	/*   REPORT_SIZE (8)                      */
+		0x81, 0x03,	/*   INPUT (Cnst,Var,Abs)                 */
+		0x95, 0x05,	/*   REPORT_COUNT (5)                     */
+		0x75, 0x01,	/*   REPORT_SIZE (1)                      */
+		0x05, 0x08,	/*   USAGE_PAGE (LEDs)                    */
+		0x19, 0x01,	/*   USAGE_MINIMUM (Num Lock)             */
+		0x29, 0x05,	/*   USAGE_MAXIMUM (Kana)                 */
+		0x91, 0x02,	/*   OUTPUT (Data,Var,Abs)                */
+		0x95, 0x01,	/*   REPORT_COUNT (1)                     */
+		0x75, 0x03,	/*   REPORT_SIZE (3)                      */
+		0x91, 0x03,	/*   OUTPUT (Cnst,Var,Abs)                */
+		0x95, 0x06,	/*   REPORT_COUNT (6)                     */
+		0x75, 0x08,	/*   REPORT_SIZE (8)                      */
+		0x15, 0x00,	/*   LOGICAL_MINIMUM (0)                  */
+		0x25, 0x65,	/*   LOGICAL_MAXIMUM (101)                */
+		0x05, 0x07,	/*   USAGE_PAGE (Keyboard)                */
+		0x19, 0x00,	/*   USAGE_MINIMUM (Reserved)             */
+		0x29, 0x65,	/*   USAGE_MAXIMUM (Keyboard Application) */
+		0x81, 0x00,	/*   INPUT (Data,Ary,Abs)                 */
+		0xc0		/* END_COLLECTION                         */
+	}
+};
diff --git a/drivers/usb/gadget/f_hid_android_mouse.c b/drivers/usb/gadget/f_hid_android_mouse.c
new file mode 100644
index 0000000..c0432b3
--- /dev/null
+++ b/drivers/usb/gadget/f_hid_android_mouse.c
@@ -0,0 +1,39 @@
+#include <linux/platform_device.h>
+#include <linux/usb/g_hid.h>
+
+/* HID descriptor for a mouse */
+static struct hidg_func_descriptor ghid_device_android_mouse = {
+	.subclass      = 1, /* Boot Interface Subclass */
+	.protocol      = 2, /* Mouse */
+	.report_length = 4,
+	.report_desc_length	= 52,
+	.report_desc = {
+		0x05, 0x01,  //Usage Page(Generic Desktop Controls)
+		0x09, 0x02,  //Usage (Mouse)
+		0xa1, 0x01,  //Collection (Application)
+		0x09, 0x01,  //Usage (pointer)
+		0xa1, 0x00,  //Collection (Physical)
+		0x05, 0x09,  //Usage Page (Button)
+		0x19, 0x01,  //Usage Minimum(1)
+		0x29, 0x05,  //Usage Maximum(5)
+		0x15, 0x00,  //Logical Minimum(1)
+		0x25, 0x01,  //Logical Maximum(1)
+		0x95, 0x05,  //Report Count(5)
+		0x75, 0x01,  //Report Size(1)
+		0x81, 0x02,  //Input(Data,Variable,Absolute,BitField)
+		0x95, 0x01,  //Report Count(1)
+		0x75, 0x03,  //Report Size(3)
+		0x81, 0x01,  //Input(Constant,Array,Absolute,BitField)
+		0x05, 0x01,  //Usage Page(Generic Desktop Controls)
+		0x09, 0x30,  //Usage(x)
+		0x09, 0x31,  //Usage(y)
+		0x09, 0x38,  //Usage(Wheel)
+		0x15, 0x81,  //Logical Minimum(-127)
+		0x25, 0x7F,  //Logical Maximum(127)
+		0x75, 0x08,  //Report Size(8)
+		0x95, 0x03,  //Report Count(3)
+		0x81, 0x06,  //Input(Data,Variable,Relative,BitField)
+		0xc0,  //End Collection
+		0xc0  //End Collection
+	}
+};