/*
 * Symbol USB barcode to serial driver
 *
 * Copyright (C) 2013 Johan Hovold <jhovold@gmail.com>
 * Copyright (C) 2009 Greg Kroah-Hartman <gregkh@suse.de>
 * Copyright (C) 2009 Novell Inc.
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License version
 *	2 as published by the Free Software Foundation.
 */

#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/slab.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/uaccess.h>

static const struct usb_device_id id_table[] = {
	{ USB_DEVICE(0x05e0, 0x0600) },
	{ },
};
MODULE_DEVICE_TABLE(usb, id_table);

struct symbol_private {
	spinlock_t lock;	/* protects the following flags */
	bool throttled;
	bool actually_throttled;
};

static void symbol_int_callback(struct urb *urb)
{
	struct usb_serial_port *port = urb->context;
	struct symbol_private *priv = usb_get_serial_port_data(port);
	unsigned char *data = urb->transfer_buffer;
	int status = urb->status;
	int result;
	int data_length;

	switch (status) {
	case 0:
		/* success */
		break;
	case -ECONNRESET:
	case -ENOENT:
	case -ESHUTDOWN:
		/* this urb is terminated, clean up */
		dev_dbg(&port->dev, "%s - urb shutting down with status: %d\n",
			__func__, status);
		return;
	default:
		dev_dbg(&port->dev, "%s - nonzero urb status received: %d\n",
			__func__, status);
		goto exit;
	}

	usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);

	/*
	 * Data from the device comes with a 1 byte header:
	 *
	 * <size of data> <data>...
	 */
	if (urb->actual_length > 1) {
		data_length = data[0];
		if (data_length > (urb->actual_length - 1))
			data_length = urb->actual_length - 1;
		tty_insert_flip_string(&port->port, &data[1], data_length);
		tty_flip_buffer_push(&port->port);
	} else {
		dev_dbg(&port->dev, "%s - short packet\n", __func__);
	}

exit:
	spin_lock(&priv->lock);

	/* Continue trying to always read if we should */
	if (!priv->throttled) {
		result = usb_submit_urb(port->interrupt_in_urb, GFP_ATOMIC);
		if (result)
			dev_err(&port->dev,
			    "%s - failed resubmitting read urb, error %d\n",
							__func__, result);
	} else
		priv->actually_throttled = true;
	spin_unlock(&priv->lock);
}

static int symbol_open(struct tty_struct *tty, struct usb_serial_port *port)
{
	struct symbol_private *priv = usb_get_serial_port_data(port);
	unsigned long flags;
	int result = 0;

	spin_lock_irqsave(&priv->lock, flags);
	priv->throttled = false;
	priv->actually_throttled = false;
	spin_unlock_irqrestore(&priv->lock, flags);

	/* Start reading from the device */
	result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
	if (result)
		dev_err(&port->dev,
			"%s - failed resubmitting read urb, error %d\n",
			__func__, result);
	return result;
}

static void symbol_close(struct usb_serial_port *port)
{
	usb_kill_urb(port->interrupt_in_urb);
}

static void symbol_throttle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct symbol_private *priv = usb_get_serial_port_data(port);

	spin_lock_irq(&priv->lock);
	priv->throttled = true;
	spin_unlock_irq(&priv->lock);
}

static void symbol_unthrottle(struct tty_struct *tty)
{
	struct usb_serial_port *port = tty->driver_data;
	struct symbol_private *priv = usb_get_serial_port_data(port);
	int result;
	bool was_throttled;

	spin_lock_irq(&priv->lock);
	priv->throttled = false;
	was_throttled = priv->actually_throttled;
	priv->actually_throttled = false;
	spin_unlock_irq(&priv->lock);

	if (was_throttled) {
		result = usb_submit_urb(port->interrupt_in_urb, GFP_KERNEL);
		if (result)
			dev_err(&port->dev,
				"%s - failed submitting read urb, error %d\n",
							__func__, result);
	}
}

static int symbol_startup(struct usb_serial *serial)
{
	if (!serial->num_interrupt_in) {
		dev_err(&serial->dev->dev, "no interrupt-in endpoint\n");
		return -ENODEV;
	}

	return 0;
}

static int symbol_port_probe(struct usb_serial_port *port)
{
	struct symbol_private *priv;

	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	spin_lock_init(&priv->lock);

	usb_set_serial_port_data(port, priv);

	return 0;
}

static int symbol_port_remove(struct usb_serial_port *port)
{
	struct symbol_private *priv = usb_get_serial_port_data(port);

	kfree(priv);

	return 0;
}

static struct usb_serial_driver symbol_device = {
	.driver = {
		.owner =	THIS_MODULE,
		.name =		"symbol",
	},
	.id_table =		id_table,
	.num_ports =		1,
	.attach =		symbol_startup,
	.port_probe =		symbol_port_probe,
	.port_remove =		symbol_port_remove,
	.open =			symbol_open,
	.close =		symbol_close,
	.throttle = 		symbol_throttle,
	.unthrottle =		symbol_unthrottle,
	.read_int_callback =	symbol_int_callback,
};

static struct usb_serial_driver * const serial_drivers[] = {
	&symbol_device, NULL
};

module_usb_serial_driver(serial_drivers, id_table);

MODULE_LICENSE("GPL");
eixner &lt;tglx@linutronix.de&gt;</td><td class='right'>2017-01-31 21:47:58 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/mon?h=nds-private-remove&amp;id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>0becc0ae5b42828785b589f686725ff5bc3b9b25</a> (<a href='/cgit.cgi/linux/net-next.git/patch/drivers/usb/mon?id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?h=nds-private-remove&amp;id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>be6d0e1f37c38ed0a7dd5da2d4b1e93f0fb43101</a> /<a href='/cgit.cgi/linux/net-next.git/tree/drivers/usb/mon?h=nds-private-remove&amp;id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>drivers/usb/mon</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/drivers/usb/mon?h=nds-private-remove&amp;id=24c2503255d35c269b67162c397a1a1c1e02f6ce'>24c2503255d35c269b67162c397a1a1c1e02f6ce</a> (<a href='/cgit.cgi/linux/net-next.git/diff/drivers/usb/mon?h=nds-private-remove&amp;id=0becc0ae5b42828785b589f686725ff5bc3b9b25&amp;id2=24c2503255d35c269b67162c397a1a1c1e02f6ce'>diff</a>)</td></tr></table>
<div class='commit-subject'>x86/mce: Make timer handling more robust</div><div class='commit-msg'>Erik reported that on a preproduction hardware a CMCI storm triggers the
BUG_ON in add_timer_on(). The reason is that the per CPU MCE timer is
started by the CMCI logic before the MCE CPU hotplug callback starts the
timer with add_timer_on(). So the timer is already queued which triggers
the BUG.

Using add_timer_on() is pretty pointless in this code because the timer is
strictlty per CPU, initialized as pinned and all operations which arm the
timer happen on the CPU to which the timer belongs.

Simplify the whole machinery by using mod_timer() instead of add_timer_on()
which avoids the problem because mod_timer() can handle already queued
timers. Use __start_timer() everywhere so the earliest armed expiry time is
preserved.

Reported-by: Erik Veijola &lt;erik.veijola@intel.com&gt;
Tested-by: Borislav Petkov &lt;bp@alien8.de&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Borislav Petkov &lt;bp@alien8.de&gt;
Cc: Tony Luck &lt;tony.luck@intel.com&gt;
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1701310936080.3457@nanos
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;

</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?h=nds-private-remove&amp;id=0becc0ae5b42828785b589f686725ff5bc3b9b25'>Diffstat</a> (limited to 'drivers/usb/mon')</div><table summary='diffstat' class='diffstat'>