linux_dsm_epyc7002/drivers/usb/serial/generic.c
Greg Kroah-Hartman 507ca9bc04 [PATCH] USB: add ability for usb-serial drivers to determine if their write urb is currently being used.
This removes a lot of racy and buggy code by trying to check the status of the urb.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2005-06-27 14:43:47 -07:00

324 lines
8.8 KiB
C

/*
* USB Serial Converter Generic functions
*
* Copyright (C) 1999 - 2002 Greg Kroah-Hartman (greg@kroah.com)
*
* 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/config.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/usb.h>
#include <asm/uaccess.h>
#include "usb-serial.h"
static int debug;
#ifdef CONFIG_USB_SERIAL_GENERIC
static __u16 vendor = 0x05f9;
static __u16 product = 0xffff;
module_param(vendor, ushort, 0);
MODULE_PARM_DESC(vendor, "User specified USB idVendor");
module_param(product, ushort, 0);
MODULE_PARM_DESC(product, "User specified USB idProduct");
static struct usb_device_id generic_device_ids[2]; /* Initially all zeroes. */
/* All of the device info needed for the Generic Serial Converter */
struct usb_serial_device_type usb_serial_generic_device = {
.owner = THIS_MODULE,
.name = "Generic",
.short_name = "generic",
.id_table = generic_device_ids,
.num_interrupt_in = NUM_DONT_CARE,
.num_bulk_in = NUM_DONT_CARE,
.num_bulk_out = NUM_DONT_CARE,
.num_ports = 1,
.shutdown = usb_serial_generic_shutdown,
};
/* we want to look at all devices, as the vendor/product id can change
* depending on the command line argument */
static struct usb_device_id generic_serial_ids[] = {
{.driver_info = 42},
{}
};
static int generic_probe(struct usb_interface *interface,
const struct usb_device_id *id)
{
const struct usb_device_id *id_pattern;
id_pattern = usb_match_id(interface, generic_device_ids);
if (id_pattern != NULL)
return usb_serial_probe(interface, id);
return -ENODEV;
}
static struct usb_driver generic_driver = {
.owner = THIS_MODULE,
.name = "usbserial_generic",
.probe = generic_probe,
.disconnect = usb_serial_disconnect,
.id_table = generic_serial_ids,
};
#endif
int usb_serial_generic_register (int _debug)
{
int retval = 0;
debug = _debug;
#ifdef CONFIG_USB_SERIAL_GENERIC
generic_device_ids[0].idVendor = vendor;
generic_device_ids[0].idProduct = product;
generic_device_ids[0].match_flags = USB_DEVICE_ID_MATCH_VENDOR | USB_DEVICE_ID_MATCH_PRODUCT;
/* register our generic driver with ourselves */
retval = usb_serial_register (&usb_serial_generic_device);
if (retval)
goto exit;
retval = usb_register(&generic_driver);
if (retval)
usb_serial_deregister(&usb_serial_generic_device);
exit:
#endif
return retval;
}
void usb_serial_generic_deregister (void)
{
#ifdef CONFIG_USB_SERIAL_GENERIC
/* remove our generic driver */
usb_deregister(&generic_driver);
usb_serial_deregister (&usb_serial_generic_device);
#endif
}
int usb_serial_generic_open (struct usb_serial_port *port, struct file *filp)
{
struct usb_serial *serial = port->serial;
int result = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
/* force low_latency on so that our tty_push actually forces the data through,
otherwise it is scheduled, and with high data rates (like with OHCI) data
can get lost. */
if (port->tty)
port->tty->low_latency = 1;
/* if we have a bulk interrupt, start reading from it */
if (serial->num_bulk_in) {
/* Start reading from the device */
usb_fill_bulk_urb (port->read_urb, serial->dev,
usb_rcvbulkpipe(serial->dev, port->bulk_in_endpointAddress),
port->read_urb->transfer_buffer,
port->read_urb->transfer_buffer_length,
((serial->type->read_bulk_callback) ?
serial->type->read_bulk_callback :
usb_serial_generic_read_bulk_callback),
port);
result = usb_submit_urb(port->read_urb, GFP_KERNEL);
if (result)
dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
}
return result;
}
static void generic_cleanup (struct usb_serial_port *port)
{
struct usb_serial *serial = port->serial;
dbg("%s - port %d", __FUNCTION__, port->number);
if (serial->dev) {
/* shutdown any bulk reads that might be going on */
if (serial->num_bulk_out)
usb_kill_urb(port->write_urb);
if (serial->num_bulk_in)
usb_kill_urb(port->read_urb);
}
}
void usb_serial_generic_close (struct usb_serial_port *port, struct file * filp)
{
dbg("%s - port %d", __FUNCTION__, port->number);
generic_cleanup (port);
}
int usb_serial_generic_write(struct usb_serial_port *port, const unsigned char *buf, int count)
{
struct usb_serial *serial = port->serial;
int result;
unsigned char *data;
dbg("%s - port %d", __FUNCTION__, port->number);
if (count == 0) {
dbg("%s - write request of 0 bytes", __FUNCTION__);
return (0);
}
/* only do something if we have a bulk out endpoint */
if (serial->num_bulk_out) {
spin_lock(&port->lock);
if (port->write_urb_busy) {
spin_unlock(&port->lock);
dbg("%s - already writing", __FUNCTION__);
return 0;
}
port->write_urb_busy = 1;
spin_unlock(&port->lock);
count = (count > port->bulk_out_size) ? port->bulk_out_size : count;
memcpy (port->write_urb->transfer_buffer, buf, count);
data = port->write_urb->transfer_buffer;
usb_serial_debug_data(debug, &port->dev, __FUNCTION__, count, data);
/* set up our urb */
usb_fill_bulk_urb (port->write_urb, serial->dev,
usb_sndbulkpipe (serial->dev,
port->bulk_out_endpointAddress),
port->write_urb->transfer_buffer, count,
((serial->type->write_bulk_callback) ?
serial->type->write_bulk_callback :
usb_serial_generic_write_bulk_callback), port);
/* send the data out the bulk port */
port->write_urb_busy = 1;
result = usb_submit_urb(port->write_urb, GFP_ATOMIC);
if (result) {
dev_err(&port->dev, "%s - failed submitting write urb, error %d\n", __FUNCTION__, result);
/* don't have to grab the lock here, as we will retry if != 0 */
port->write_urb_busy = 0;
} else
result = count;
return result;
}
/* no bulk out, so return 0 bytes written */
return 0;
}
int usb_serial_generic_write_room (struct usb_serial_port *port)
{
struct usb_serial *serial = port->serial;
int room = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
if (serial->num_bulk_out) {
if (port->write_urb_busy)
room = port->bulk_out_size;
}
dbg("%s - returns %d", __FUNCTION__, room);
return (room);
}
int usb_serial_generic_chars_in_buffer (struct usb_serial_port *port)
{
struct usb_serial *serial = port->serial;
int chars = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
if (serial->num_bulk_out) {
if (port->write_urb_busy)
chars = port->write_urb->transfer_buffer_length;
}
dbg("%s - returns %d", __FUNCTION__, chars);
return (chars);
}
void usb_serial_generic_read_bulk_callback (struct urb *urb, struct pt_regs *regs)
{
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
struct usb_serial *serial = port->serial;
struct tty_struct *tty;
unsigned char *data = urb->transfer_buffer;
int i;
int result;
dbg("%s - port %d", __FUNCTION__, port->number);
if (urb->status) {
dbg("%s - nonzero read bulk status received: %d", __FUNCTION__, urb->status);
return;
}
usb_serial_debug_data(debug, &port->dev, __FUNCTION__, urb->actual_length, data);
tty = port->tty;
if (tty && urb->actual_length) {
for (i = 0; i < urb->actual_length ; ++i) {
/* if we insert more than TTY_FLIPBUF_SIZE characters, we drop them. */
if(tty->flip.count >= TTY_FLIPBUF_SIZE) {
tty_flip_buffer_push(tty);
}
/* this doesn't actually push the data through unless tty->low_latency is set */
tty_insert_flip_char(tty, data[i], 0);
}
tty_flip_buffer_push(tty);
}
/* Continue trying to always read */
usb_fill_bulk_urb (port->read_urb, serial->dev,
usb_rcvbulkpipe (serial->dev,
port->bulk_in_endpointAddress),
port->read_urb->transfer_buffer,
port->read_urb->transfer_buffer_length,
((serial->type->read_bulk_callback) ?
serial->type->read_bulk_callback :
usb_serial_generic_read_bulk_callback), port);
result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
if (result)
dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
}
void usb_serial_generic_write_bulk_callback (struct urb *urb, struct pt_regs *regs)
{
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
dbg("%s - port %d", __FUNCTION__, port->number);
port->write_urb_busy = 0;
if (urb->status) {
dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
return;
}
usb_serial_port_softint((void *)port);
schedule_work(&port->work);
}
void usb_serial_generic_shutdown (struct usb_serial *serial)
{
int i;
dbg("%s", __FUNCTION__);
/* stop reads and writes on all ports */
for (i=0; i < serial->num_ports; ++i) {
generic_cleanup(serial->port[i]);
}
}