Fixed MTP to work with TWRP

drivers/usb/gadget/function/serial_acm.c

@@ -0,0 +1,174 @@
+/*
+ * serial_acm.c -- USB modem serial driver
+ *
+ * Copyright 2008 (C) Samsung Electronics
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/fs.h>
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+
+#include <linux/uaccess.h>
+#include <linux/io.h>
+
+#include <linux/interrupt.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/usb/cdc.h>
+
+extern int acm_notify(void *dev, u16 state);
+
+
+static wait_queue_head_t modem_wait_q;
+
+static unsigned int read_state;
+static unsigned int control_line_state;
+
+static void *acm_data;
+
+static int modem_open(struct inode *inode, struct file *file)
+{
+	read_state = 0;
+
+	return 0;
+}
+
+static int modem_close(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
+static ssize_t modem_read(struct file *file, char __user *buf,
+		size_t count, loff_t *ppos)
+{
+	int ret = 0;
+
+	if (file->f_flags & O_NONBLOCK)
+		return -EAGAIN;
+
+	ret = wait_event_interruptible(modem_wait_q, read_state);
+	if (ret)
+		return ret;
+
+	if (copy_to_user(buf, &control_line_state, sizeof(u32)))
+		return -EFAULT;
+
+	read_state = 0;
+
+	return sizeof(u32);
+}
+
+static unsigned int modem_poll(struct file *file, poll_table *wait)
+{
+	int ret;
+	poll_wait(file, &modem_wait_q, wait);
+
+	ret = (read_state ? (POLLIN | POLLRDNORM) : 0);
+
+	return ret;
+}
+
+void notify_control_line_state(u32 value)
+{
+	control_line_state = value;
+
+	read_state = 1;
+
+	wake_up_interruptible(&modem_wait_q);
+}
+EXPORT_SYMBOL(notify_control_line_state);
+
+
+#define GS_CDC_NOTIFY_SERIAL_STATE	_IOW('S', 1, int)
+#define GS_IOC_NOTIFY_DTR_TEST		_IOW('S', 3, int)
+
+static long
+modem_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
+{
+
+	printk(KERN_INFO "modem_ioctl: cmd=0x%x, arg=%lu\n", cmd, arg);
+
+	/* handle ioctls */
+	switch (cmd) {
+	case GS_CDC_NOTIFY_SERIAL_STATE:
+		acm_notify(acm_data, __constant_cpu_to_le16(arg));
+		break;
+
+	case GS_IOC_NOTIFY_DTR_TEST:
+		{
+			printk(KERN_ALERT"DUN : DTR %d\n", (int)arg);
+			notify_control_line_state((int)arg);
+			break;
+		}
+
+	default:
+		printk(KERN_INFO "modem_ioctl: Unknown ioctl cmd(0x%x).\n",
+				cmd);
+		return -ENOIOCTLCMD;
+	}
+	return 0;
+}
+
+
+static const struct file_operations modem_fops = {
+	.owner		= THIS_MODULE,
+	.open		= modem_open,
+	.release	= modem_close,
+	.read		= modem_read,
+	.poll		= modem_poll,
+	.llseek		= no_llseek,
+	.unlocked_ioctl	= modem_ioctl,
+};
+
+static struct miscdevice modem_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name	= "dun",
+	.fops	= &modem_fops,
+};
+
+int modem_register(void *data)
+{
+	if (data == NULL) {
+		printk(KERN_INFO "DUN register failed. data is null.\n");
+		return -1;
+	}
+
+	acm_data = data;
+
+	printk(KERN_INFO "DUN is registerd\n");
+
+	return 0;
+}
+EXPORT_SYMBOL(modem_register);
+
+int modem_misc_register(void)
+{
+	int ret;
+	ret = misc_register(&modem_device);
+	if (ret) {
+		printk(KERN_ERR "DUN register is failed, ret = %d\n", ret);
+		return ret;
+	}
+
+	init_waitqueue_head(&modem_wait_q);
+	return ret;
+}
+EXPORT_SYMBOL(modem_misc_register);
+
+void modem_unregister(void)
+{
+	acm_data = NULL;
+
+	notify_control_line_state(0);
+
+	printk(KERN_INFO "DUN is unregisterd\n");
+}
+EXPORT_SYMBOL(modem_unregister);