From: Jon Masters <jcm@redhat.com>
Subject: [RHEL5 PATCH]: BZ#222443 airprime driver corrupts ppp session for EVDO card
Date: Mon, 29 Jan 2007 14:53:23 -0500
Bugzilla: 222443
Message-Id: <20070129195323.GA20889@devserv.devel.redhat.com>
Changelog: [usb]: airprime driver corrupts ppp session for EVDO card


This patch updates the RHEL5 Airprime USB driver to add improved flow control
so that it no longer dies under heavy system load. This patch is formed from
two upstream changesets and has been tested by Rod Nayfield on his laptop.

diff -urNp linux-2.6.18.noarch_orig/drivers/usb/serial/airprime.c linux-2.6.18.noarch/drivers/usb/serial/airprime.c
--- linux-2.6.18.noarch_orig/drivers/usb/serial/airprime.c	2006-09-19 23:42:06.000000000 -0400
+++ linux-2.6.18.noarch/drivers/usb/serial/airprime.c	2007-01-26 14:08:47.000000000 -0500
@@ -1,7 +1,7 @@
 /*
  * AirPrime CDMA Wireless Serial USB driver
  *
- * Copyright (C) 2005 Greg Kroah-Hartman <gregkh@suse.de>
+ * Copyright (C) 2005-2006 Greg Kroah-Hartman <gregkh@suse.de>
  *
  *	This program is free software; you can redistribute it and/or
  *	modify it under the terms of the GNU General Public License version
@@ -11,26 +11,265 @@
 #include <linux/kernel.h>
 #include <linux/init.h>
 #include <linux/tty.h>
+#include <linux/tty_flip.h>
 #include <linux/module.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
 
 static struct usb_device_id id_table [] = {
 	{ USB_DEVICE(0x0c88, 0x17da) }, /* Kyocera Wireless KPC650/Passport */
-	{ USB_DEVICE(0xf3d, 0x0112) },  /* AirPrime CDMA Wireless PC Card */
-	{ USB_DEVICE(0x1410, 0x1110) }, /* Novatel Wireless Merlin CDMA */
+	{ USB_DEVICE(0x0f3d, 0x0112) }, /* AirPrime CDMA Wireless PC Card */
+	{ USB_DEVICE(0x1199, 0x0017) }, /* Sierra Wireless EM5625 */
+	{ USB_DEVICE(0x1199, 0x0018) }, /* Sierra Wireless MC5720 */
 	{ USB_DEVICE(0x1199, 0x0112) }, /* Sierra Wireless Aircard 580 */
 	{ USB_DEVICE(0x1199, 0x0218) }, /* Sierra Wireless MC5720 */
+	{ USB_DEVICE(0x1410, 0x1110) }, /* Novatel Wireless Merlin CDMA */
 	{ },
 };
 MODULE_DEVICE_TABLE(usb, id_table);
 
+#define URB_TRANSFER_BUFFER_SIZE	4096
+#define NUM_READ_URBS			4
+#define NUM_WRITE_URBS			4
+#define NUM_BULK_EPS			3
+#define MAX_BULK_EPS			6
+
+/* if overridden by the user, then use their value for the size of the
+ * read and write urbs, and the number of endpoints */
+static int buffer_size = URB_TRANSFER_BUFFER_SIZE;
+static int endpoints = NUM_BULK_EPS;
+static int debug;
+struct airprime_private {
+	spinlock_t lock;
+	int outstanding_urbs;
+	int throttled;
+	struct urb *read_urbp[NUM_READ_URBS];
+};
+
+static void airprime_read_bulk_callback(struct urb *urb, struct pt_regs *regs)
+{
+	struct usb_serial_port *port = urb->context;
+	unsigned char *data = urb->transfer_buffer;
+	struct tty_struct *tty;
+	int result;
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	if (urb->status) {
+		dbg("%s - nonzero read bulk status received: %d",
+		    __FUNCTION__, urb->status);
+		/* something happened, so free up the memory for this urb */
+		if (urb->transfer_buffer) {
+			kfree (urb->transfer_buffer);
+			urb->transfer_buffer = NULL;
+		}
+		return;
+	}
+	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
+
+	tty = port->tty;
+	if (tty && urb->actual_length) {
+		tty_insert_flip_string (tty, data, urb->actual_length);
+		tty_flip_buffer_push (tty);
+	}
+
+	result = usb_submit_urb (urb, GFP_ATOMIC);
+	if (result)
+		dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n",
+			__FUNCTION__, result);
+	return;
+}
+
+static void airprime_write_bulk_callback(struct urb *urb, struct pt_regs *regs)
+{
+	struct usb_serial_port *port = urb->context;
+	struct airprime_private *priv = usb_get_serial_port_data(port);
+	unsigned long flags;
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	/* free up the transfer buffer, as usb_free_urb() does not do this */
+	kfree (urb->transfer_buffer);
+
+	if (urb->status)
+		dbg("%s - nonzero write bulk status received: %d",
+		    __FUNCTION__, urb->status);
+	spin_lock_irqsave(&priv->lock, flags);
+	--priv->outstanding_urbs;
+	spin_unlock_irqrestore(&priv->lock, flags);
+
+	usb_serial_port_softint(port);
+}
+
+static int airprime_open(struct usb_serial_port *port, struct file *filp)
+{
+	struct airprime_private *priv = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	struct urb *urb;
+	char *buffer = NULL;
+	int i;
+	int result = 0;
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	/* initialize our private data structure if it isn't already created */
+	if (!priv) {
+		priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+		if (!priv) {
+			result = -ENOMEM;
+			goto out;
+		}
+		spin_lock_init(&priv->lock);
+		usb_set_serial_port_data(port, priv);
+	}
+
+	for (i = 0; i < NUM_READ_URBS; ++i) {
+		buffer = kmalloc(buffer_size, GFP_KERNEL);
+		if (!buffer) {
+			dev_err(&port->dev, "%s - out of memory.\n",
+				__FUNCTION__);
+			result = -ENOMEM;
+			goto errout;
+		}
+		urb = usb_alloc_urb(0, GFP_KERNEL);
+		if (!urb) {
+			kfree(buffer);
+			dev_err(&port->dev, "%s - no more urbs?\n",
+				__FUNCTION__);
+			result = -ENOMEM;
+			goto errout;
+		}
+		usb_fill_bulk_urb(urb, serial->dev,
+				  usb_rcvbulkpipe(serial->dev,
+						  port->bulk_out_endpointAddress),
+				  buffer, buffer_size,
+				  airprime_read_bulk_callback, port);
+		result = usb_submit_urb(urb, GFP_KERNEL);
+		if (result) {
+			dev_err(&port->dev,
+				"%s - failed submitting read urb %d for port %d, error %d\n",
+				__FUNCTION__, i, port->number, result);
+			goto errout;
+		}
+		/* remember this urb so we can kill it when the port is closed */
+		priv->read_urbp[i] = urb;
+	}
+	goto out;
+
+ errout:
+	/* some error happened, cancel any submitted urbs and clean up anything that
+	   got allocated successfully */
+
+	for ( ; i >= 0; --i) {
+		urb = priv->read_urbp[i];
+		if (urb) {
+			/* This urb was submitted successfully. So we have to
+			   cancel it.
+			   Unlinking the urb will invoke read_bulk_callback()
+			   with an error status, so its transfer buffer will
+			   be freed there */
+			if (usb_unlink_urb (urb) != -EINPROGRESS) {
+				/* comments in drivers/usb/core/urb.c say this
+				   can only happen if the urb was never submitted,
+				   or has completed already.
+				   Either way we may have to free the transfer
+				   buffer here. */
+				if (urb->transfer_buffer) {
+					kfree (urb->transfer_buffer);
+					urb->transfer_buffer = NULL;
+				}
+			}
+			usb_free_urb (urb);
+		}
+	}
+
+ out:
+	return result;
+}
+
+static void airprime_close(struct usb_serial_port *port, struct file * filp)
+{
+	struct airprime_private *priv = usb_get_serial_port_data(port);
+	int i;
+
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	/* killing the urb will invoke read_bulk_callback() with an error status,
+	   so the transfer buffer will be freed there */
+	for (i = 0; i < NUM_READ_URBS; ++i) {
+		usb_kill_urb (priv->read_urbp[i]);
+		usb_free_urb (priv->read_urbp[i]);
+	}
+
+	/* free up private structure */
+	kfree (priv);
+	usb_set_serial_port_data(port, NULL);
+}
+
+static int airprime_write(struct usb_serial_port *port,
+			  const unsigned char *buf, int count)
+{
+	struct airprime_private *priv = usb_get_serial_port_data(port);
+	struct usb_serial *serial = port->serial;
+	struct urb *urb;
+	unsigned char *buffer;
+	unsigned long flags;
+	int status;
+	dbg("%s - port %d", __FUNCTION__, port->number);
+
+	spin_lock_irqsave(&priv->lock, flags);
+	if (priv->outstanding_urbs > NUM_WRITE_URBS) {
+		spin_unlock_irqrestore(&priv->lock, flags);
+		dbg("%s - write limit hit\n", __FUNCTION__);
+		return 0;
+	}
+	spin_unlock_irqrestore(&priv->lock, flags);
+	buffer = kmalloc(count, GFP_ATOMIC);
+	if (!buffer) {
+		dev_err(&port->dev, "out of memory\n");
+		return -ENOMEM;
+	}
+	urb = usb_alloc_urb(0, GFP_ATOMIC);
+	if (!urb) {
+		dev_err(&port->dev, "no more free urbs\n");
+		kfree (buffer);
+		return -ENOMEM;
+	}
+	memcpy (buffer, buf, count);
+
+	usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, buffer);
+
+	usb_fill_bulk_urb(urb, serial->dev,
+			  usb_sndbulkpipe(serial->dev,
+					  port->bulk_out_endpointAddress),
+			  buffer, count,
+			  airprime_write_bulk_callback, port);
+
+	/* send it down the pipe */
+	status = usb_submit_urb(urb, GFP_ATOMIC);
+	if (status) {
+		dev_err(&port->dev,
+			"%s - usb_submit_urb(write bulk) failed with status = %d\n",
+			__FUNCTION__, status);
+		count = status;
+		kfree (buffer);
+	} else {
+		spin_lock_irqsave(&priv->lock, flags);
+		++priv->outstanding_urbs;
+		spin_unlock_irqrestore(&priv->lock, flags);
+	}
+	/* we are done with this urb, so let the host driver
+	 * really free it when it is finished with it */
+	usb_free_urb (urb);
+	return count;
+}
+
 static struct usb_driver airprime_driver = {
 	.name =		"airprime",
 	.probe =	usb_serial_probe,
 	.disconnect =	usb_serial_disconnect,
 	.id_table =	id_table,
-	.no_dynamic_id = 	1,
+	.no_dynamic_id =	1,
 };
 
 static struct usb_serial_driver airprime_device = {
@@ -42,13 +281,17 @@ static struct usb_serial_driver airprime
 	.num_interrupt_in =	NUM_DONT_CARE,
 	.num_bulk_in =		NUM_DONT_CARE,
 	.num_bulk_out =		NUM_DONT_CARE,
-	.num_ports =		1,
+	.open =			airprime_open,
+	.close =		airprime_close,
+	.write =		airprime_write,
 };
 
 static int __init airprime_init(void)
 {
 	int retval;
 
+	airprime_device.num_ports =
+		(endpoints > 0 && endpoints <= MAX_BULK_EPS) ? endpoints : NUM_BULK_EPS;
 	retval = usb_serial_register(&airprime_device);
 	if (retval)
 		return retval;
@@ -60,6 +303,8 @@ static int __init airprime_init(void)
 
 static void __exit airprime_exit(void)
 {
+	dbg("%s", __FUNCTION__);
+
 	usb_deregister(&airprime_driver);
 	usb_serial_deregister(&airprime_device);
 }
@@ -67,3 +312,10 @@ static void __exit airprime_exit(void)
 module_init(airprime_init);
 module_exit(airprime_exit);
 MODULE_LICENSE("GPL");
+
+module_param(debug, bool, S_IRUGO | S_IWUSR);
+MODULE_PARM_DESC(debug, "Debug enabled");
+module_param(buffer_size, int, 0);
+MODULE_PARM_DESC(buffer_size, "Size of the transfer buffers in bytes (default 4096)");
+module_param(endpoints, int, 0);
+MODULE_PARM_DESC(endpoints, "Number of bulk EPs to configure (default 3)");