Allow f_acm gadgets to notify the user about SetLineCoding requests

index bdf0e6e..7af8c29 100644
@@ -2394,6 +2394,8 @@ static unsigned int n_tty_poll(struct tty_struct *tty, struct file *file,
 			tty_chars_in_buffer(tty) < WAKEUP_CHARS &&
 			tty_write_room(tty) > 0)
 		mask |= POLLOUT | POLLWRNORM;
+	if (tty->ops->poll)
+		mask |= tty->ops->poll(tty, file, wait);
 	return mask;
 }
 

index b742b5e..630ef03 100644
@@ -243,6 +243,7 @@
 #include <linux/list.h>
 #include <linux/cdev.h>
 #include <linux/termios.h>
+#include <linux/poll.h>
 
 struct tty_struct;
 struct tty_driver;

@@ -285,6 +286,8 @@ struct tty_operations {
 	int (*set_termiox)(struct tty_struct *tty, struct termiox *tnew);
 	int (*get_icount)(struct tty_struct *tty,
 				struct serial_icounter_struct *icount);
+	unsigned int (*poll)(struct tty_struct *tty, struct file *file,
+				poll_table *wait);
 #ifdef CONFIG_CONSOLE_POLL
 	int (*poll_init)(struct tty_driver *driver, int line, char *options);
 	int (*poll_get_char)(struct tty_driver *driver, int line);

index 9b0805f..d466f58 100644
@@ -1025,6 +1025,21 @@ static int gs_break_ctl(struct tty_struct *tty, int duration)
 	return status;
 }
 
+static unsigned int gs_poll(struct tty_struct *tty, struct file *file,
+	poll_table *wait)
+{
+	struct gs_port *port = tty->driver_data;
+	struct gserial *gser;
+	unsigned int mask = 0;
+
+	spin_lock_irq(&port->port_lock);
+	gser = port->port_usb;
+	if (gser && gser->poll)
+		mask |= gser->poll(gser, file, wait);
+	spin_unlock_irq(&port->port_lock);
+	return mask;
+}
+
 static const struct tty_operations gs_tty_ops = {
 	.open =			gs_open,
 	.close =		gs_close,

@@ -1035,6 +1050,7 @@ static const struct tty_operations gs_tty_ops = {
 	.chars_in_buffer =	gs_chars_in_buffer,
 	.unthrottle =		gs_unthrottle,
 	.break_ctl =		gs_break_ctl,
+	.poll =			gs_poll,
 };
 
 /*-------------------------------------------------------------------------*/

index c20210c..ce00840 100644
@@ -12,6 +12,7 @@
 #ifndef __U_SERIAL_H
 #define __U_SERIAL_H
 
+#include <linux/poll.h>
 #include <linux/usb/composite.h>
 #include <linux/usb/cdc.h>
 

@@ -50,6 +51,8 @@ struct gserial {
 	void (*connect)(struct gserial *p);
 	void (*disconnect)(struct gserial *p);
 	int (*send_break)(struct gserial *p, int duration);
+	unsigned int (*poll)(struct gserial *p, struct file *file,
+				poll_table *wait);
 };
 
 /* utilities to allocate/free request and buffer */

index 5e3828d..e023313 100644
@@ -326,13 +326,22 @@ static void acm_complete_set_line_coding(struct usb_ep *ep,
 		struct usb_cdc_line_coding	*value = req->buf;
 
 		/* REVISIT:  we currently just remember this data.
-		 * If we change that, (a) validate it first, then
-		 * (b) update whatever hardware needs updating,
-		 * (c) worry about locking.  This is information on
-		 * the order of 9600-8-N-1 ... most of which means
-		 * nothing unless we control a real RS232 line.
-		 */
-		acm->port_line_coding = *value;
+		* If we change that,
+		* (a) update whatever hardware needs updating,
+		* (b) worry about locking.  This is information on
+		* the order of 9600-8-N-1 ... most of which means
+		* nothing unless we control a real RS232 line.
+		*/
+		dev_dbg(&cdev->gadget->dev,
+			"acm ttyGS%d set_line_coding: %d %d %d %d\n",
+			acm->port_num, le32_to_cpu(value->dwDTERate),
+			value->bCharFormat, value->bParityType,
+			value->bDataBits);
+		if (value->bCharFormat > 2 || value->bParityType > 4 ||
+				value->bDataBits < 5 || value->bDataBits > 8)
+			usb_ep_set_halt(ep);
+		else
+			acm->port_line_coding = *value;
 	}
 }
 

index d466f58..8d9abf1 100644
@@ -1040,6 +1040,20 @@ static unsigned int gs_poll(struct tty_struct *tty, struct file *file,
 	return mask;
 }
 
+static int gs_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
+{
+	struct gs_port *port = tty->driver_data;
+	struct gserial *gser;
+	int ret = -ENOIOCTLCMD;
+
+	spin_lock_irq(&port->port_lock);
+	gser = port->port_usb;
+	if (gser && gser->ioctl)
+		ret = gser->ioctl(gser, cmd, arg);
+	spin_unlock_irq(&port->port_lock);
+	return ret;
+}
+
 static const struct tty_operations gs_tty_ops = {
 	.open =			gs_open,
 	.close =		gs_close,

@@ -1051,6 +1065,7 @@ static const struct tty_operations gs_tty_ops = {
 	.unthrottle =		gs_unthrottle,
 	.break_ctl =		gs_break_ctl,
 	.poll =			gs_poll,
+	.ioctl =		gs_ioctl,
 };
 
 /*-------------------------------------------------------------------------*/

index ce00840..8d0901e 100644
@@ -53,6 +53,7 @@ struct gserial {
 	int (*send_break)(struct gserial *p, int duration);
 	unsigned int (*poll)(struct gserial *p, struct file *file,
 				poll_table *wait);
+	int (*ioctl)(struct gserial *p, unsigned int cmd, unsigned long arg);
 };
 
 /* utilities to allocate/free request and buffer */

index e023313..b7a1466 100644
@@ -763,6 +763,12 @@ static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 	acm->port.func.unbind = acm_unbind;
 	acm->port.func.free_func = acm_free_func;
 
+	/* initialize port_line_coding with something that makes sense */
+	coding.dwDTERate = cpu_to_le32(9600);
+	coding.bCharFormat = USB_CDC_1_STOP_BITS;
+	coding.bParityType = USB_CDC_NO_PARITY;
+	coding.bDataBits = 8;
+
 	return &acm->port.func;
 }
 

index b7a1466..5feea7c 100644
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/err.h>
+#include <uapi/linux/usb/f_acm.h>
 
 #include "u_serial.h"
 

@@ -611,6 +612,23 @@ static int acm_send_break(struct gserial *port, int duration)
 	return acm_notify_serial_state(acm);
 }
 
+static int acm_ioctl(struct gserial *port, unsigned int cmd, unsigned long arg)
+{
+	struct f_acm	*acm = port_to_acm(port);
+	int 		ret = -ENOIOCTLCMD;
+
+	switch (cmd) {
+	case USB_F_ACM_GET_LINE_CODING:
+		if (copy_to_user((__user void *)arg, &acm->port_line_coding,
+				sizeof(acm->port_line_coding)))
+			ret = -EFAULT;
+		else
+			ret = 0;
+		break;
+	}
+	return ret;
+}
+
 /*-------------------------------------------------------------------------*/
 
 /* ACM function driver setup/binding */

@@ -749,6 +767,7 @@ static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 	acm->port.connect = acm_connect;
 	acm->port.disconnect = acm_disconnect;
 	acm->port.send_break = acm_send_break;
+	acm->port.ioctl = acm_ioctl;
 
 	acm->port.func.name = "acm";
 	acm->port.func.strings = acm_strings;

@@ -764,10 +783,10 @@ static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 	acm->port.func.free_func = acm_free_func;
 
 	/* initialize port_line_coding with something that makes sense */
-	coding.dwDTERate = cpu_to_le32(9600);
-	coding.bCharFormat = USB_CDC_1_STOP_BITS;
-	coding.bParityType = USB_CDC_NO_PARITY;
-	coding.bDataBits = 8;
+	acm->port_line_coding.dwDTERate = cpu_to_le32(9600);
+	acm->port_line_coding.bCharFormat = USB_CDC_1_STOP_BITS;
+	acm->port_line_coding.bParityType = USB_CDC_NO_PARITY;
+	acm->port_line_coding.bDataBits = 8;
 
 	return &acm->port.func;
 }

new file mode 100644
index 0000000..51f96f0
@@ -0,0 +1,12 @@
+/* f_acm.h -- Header file for USB CDC-ACM gadget function */
+
+#ifndef __UAPI_LINUX_USB_F_ACM_H
+#define __UAPI_LINUX_USB_F_ACM_H
+
+#include <linux/usb/cdc.h>
+#include <linux/ioctl.h>
+
+/* The 0xCD code is also used by reiserfs. we use 0x10-0x1F range */
+#define USB_F_ACM_GET_LINE_CODING _IOR(0xCD, 0x10, struct usb_cdc_line_coding)
+
+#endif /* __UAPI_LINUX_USB_F_ACM_H */

index b7a1466..5feea7c 100644
@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/device.h>
 #include <linux/err.h>
+#include <uapi/linux/usb/f_acm.h>
 
 #include "u_serial.h"
 

@@ -611,6 +612,23 @@ static int acm_send_break(struct gserial *port, int duration)
 	return acm_notify_serial_state(acm);
 }
 
+static int acm_ioctl(struct gserial *port, unsigned int cmd, unsigned long arg)
+{
+	struct f_acm	*acm = port_to_acm(port);
+	int 		ret = -ENOIOCTLCMD;
+
+	switch (cmd) {
+	case USB_F_ACM_GET_LINE_CODING:
+		if (copy_to_user((__user void *)arg, &acm->port_line_coding,
+				sizeof(acm->port_line_coding)))
+			ret = -EFAULT;
+		else
+			ret = 0;
+		break;
+	}
+	return ret;
+}
+
 /*-------------------------------------------------------------------------*/
 
 /* ACM function driver setup/binding */

@@ -749,6 +767,7 @@ static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 	acm->port.connect = acm_connect;
 	acm->port.disconnect = acm_disconnect;
 	acm->port.send_break = acm_send_break;
+	acm->port.ioctl = acm_ioctl;
 
 	acm->port.func.name = "acm";
 	acm->port.func.strings = acm_strings;

new file mode 100644
index 0000000..51f96f0
@@ -0,0 +1,12 @@
+/* f_acm.h -- Header file for USB CDC-ACM gadget function */
+
+#ifndef __UAPI_LINUX_USB_F_ACM_H
+#define __UAPI_LINUX_USB_F_ACM_H
+
+#include <linux/usb/cdc.h>
+#include <linux/ioctl.h>
+
+/* The 0xCD code is also used by reiserfs. we use 0x10-0x1F range */
+#define USB_F_ACM_GET_LINE_CODING _IOR(0xCD, 0x10, struct usb_cdc_line_coding)
+
+#endif /* __UAPI_LINUX_USB_F_ACM_H */

index 5feea7c..0983999 100644
@@ -58,6 +58,9 @@ struct f_acm {
 	struct usb_request		*notify_req;
 
 	struct usb_cdc_line_coding	port_line_coding;	/* 8-N-1 etc */
+	/* we have a SetLineCoding request that the user haven't read yet */
+	bool set_line_coding_pending;
+	wait_queue_head_t set_line_coding_waitq;
 
 	/* SetControlLineState request -- CDC 1.1 section 6.2.14 (INPUT) */
 	u16				port_handshake_bits;

@@ -326,23 +329,19 @@ static void acm_complete_set_line_coding(struct usb_ep *ep,
 	} else {
 		struct usb_cdc_line_coding	*value = req->buf;
 
-		/* REVISIT:  we currently just remember this data.
-		* If we change that,
-		* (a) update whatever hardware needs updating,
-		* (b) worry about locking.  This is information on
-		* the order of 9600-8-N-1 ... most of which means
-		* nothing unless we control a real RS232 line.
-		*/
 		dev_dbg(&cdev->gadget->dev,
 			"acm ttyGS%d set_line_coding: %d %d %d %d\n",
 			acm->port_num, le32_to_cpu(value->dwDTERate),
 			value->bCharFormat, value->bParityType,
 			value->bDataBits);
 		if (value->bCharFormat > 2 || value->bParityType > 4 ||
-				value->bDataBits < 5 || value->bDataBits > 8)
+				value->bDataBits < 5 || value->bDataBits > 8) {
 			usb_ep_set_halt(ep);
-		else
+		} else {
 			acm->port_line_coding = *value;
+			acm->set_line_coding_pending = true;
+			wake_up_interruptible(&acm->set_line_coding_waitq);
+		}
 	}
 }
 

@@ -598,6 +597,19 @@ static void acm_disconnect(struct gserial *port)
 	acm_notify_serial_state(acm);
 }
 
+static unsigned int acm_poll(struct gserial *port, struct file *file,
+	poll_table *wait)
+{
+	unsigned int mask = 0;
+	struct f_acm *acm = port_to_acm(port);
+
+	poll_wait(file, &acm->set_line_coding_waitq, wait);
+	if (acm->set_line_coding_pending)
+		mask |= POLLPRI;
+	return mask;
+}
+
+
 static int acm_send_break(struct gserial *port, int duration)
 {
 	struct f_acm		*acm = port_to_acm(port);

@@ -620,10 +632,12 @@ static int acm_ioctl(struct gserial *port, unsigned int cmd, unsigned long arg)
 	switch (cmd) {
 	case USB_F_ACM_GET_LINE_CODING:
 		if (copy_to_user((__user void *)arg, &acm->port_line_coding,
-				sizeof(acm->port_line_coding)))
+				sizeof(acm->port_line_coding))) {
 			ret = -EFAULT;
-		else
+		} else {
 			ret = 0;
+			acm->set_line_coding_pending = false;
+		}
 		break;
 	}
 	return ret;

@@ -763,11 +777,13 @@ static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
 		return ERR_PTR(-ENOMEM);
 
 	spin_lock_init(&acm->lock);
+	init_waitqueue_head(&acm->set_line_coding_waitq);
 
 	acm->port.connect = acm_connect;
 	acm->port.disconnect = acm_disconnect;
 	acm->port.send_break = acm_send_break;
 	acm->port.ioctl = acm_ioctl;
+	acm->port.poll = acm_poll;
 
 	acm->port.func.name = "acm";
 	acm->port.func.strings = acm_strings;

index 8d9abf1..654d4a6 100644
@@ -129,9 +129,6 @@ struct gs_port {
 	wait_queue_head_t	drain_wait;	/* wait while writes drain */
 	bool                    write_busy;
 	wait_queue_head_t	close_wait;
-
-	/* REVISIT this state ... */
-	struct usb_cdc_line_coding port_line_coding;	/* 8-N-1 etc */
 };
 
 static struct portmaster {

@@ -1314,7 +1311,7 @@ static void gserial_console_exit(void)
 #endif
 
 static int
-gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
+gs_port_alloc(unsigned port_num)
 {
 	struct gs_port	*port;
 	int		ret = 0;

@@ -1343,7 +1340,6 @@ gs_port_alloc(unsigned port_num, struct usb_cdc_line_coding *coding)
 	INIT_LIST_HEAD(&port->write_pool);
 
 	port->port_num = port_num;
-	port->port_line_coding = *coding;
 
 	ports[port_num].port = port;
 out:

@@ -1392,18 +1388,12 @@ EXPORT_SYMBOL_GPL(gserial_free_line);
 
 int gserial_alloc_line(unsigned char *line_num)
 {
-	struct usb_cdc_line_coding	coding;
 	struct device			*tty_dev;
 	int				ret;
 	int				port_num;
 
-	coding.dwDTERate = cpu_to_le32(9600);
-	coding.bCharFormat = 8;
-	coding.bParityType = USB_CDC_NO_PARITY;
-	coding.bDataBits = USB_CDC_1_STOP_BITS;
-
 	for (port_num = 0; port_num < MAX_U_SERIAL_PORTS; port_num++) {
-		ret = gs_port_alloc(port_num, &coding);
+		ret = gs_port_alloc(port_num);
 		if (ret == -EBUSY)
 			continue;
 		if (ret)

@@ -1491,11 +1481,6 @@ int gserial_connect(struct gserial *gser, u8 port_num)
 	gser->ioport = port;
 	port->port_usb = gser;
 
-	/* REVISIT unclear how best to handle this state...
-	 * we don't really couple it with the Linux TTY.
-	 */
-	gser->port_line_coding = port->port_line_coding;
-
 	/* REVISIT if waiting on "carrier detect", signal. */
 
 	/* if it's already open, start I/O ... and notify the serial

@@ -1543,9 +1528,6 @@ void gserial_disconnect(struct gserial *gser)
 	/* tell the TTY glue not to do I/O here any more */
 	spin_lock_irqsave(&port->port_lock, flags);
 
-	/* REVISIT as above: how best to track this? */
-	port->port_line_coding = gser->port_line_coding;
-
 	port->port_usb = NULL;
 	gser->ioport = NULL;
 	if (port->port.count > 0 || port->openclose) {

index 8d0901e..0549efe 100644
@@ -44,9 +44,6 @@ struct gserial {
 	struct usb_ep			*in;
 	struct usb_ep			*out;
 
-	/* REVISIT avoid this CDC-ACM support harder ... */
-	struct usb_cdc_line_coding port_line_coding;	/* 9600-8-N-1 etc */
-
 	/* notification callbacks */
 	void (*connect)(struct gserial *p);
 	void (*disconnect)(struct gserial *p);