linux/drivers/usb/serial/generic.c
Johan Hovold 818f60365a USB: serial: add memory flags to usb_serial_generic_write_start
Add memory-flags parameter to usb_serial_generic_write_start which is
called from write, resume and completion handler, all with different
allocation requirements.

Note that by using the memory flag to determine when called from the
completion handler, everything will work as before even if the
completion handler is run with interrupts enabled (as suggested).

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-11 17:00:26 -07:00

612 lines
15 KiB
C

/*
* USB Serial Converter Generic functions
*
* Copyright (C) 2010 - 2013 Johan Hovold (jhovold@gmail.com)
* 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/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/sysrq.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/uaccess.h>
#include <linux/kfifo.h>
#include <linux/serial.h>
#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. */
struct usb_serial_driver usb_serial_generic_device = {
.driver = {
.owner = THIS_MODULE,
.name = "generic",
},
.id_table = generic_device_ids,
.num_ports = 1,
.throttle = usb_serial_generic_throttle,
.unthrottle = usb_serial_generic_unthrottle,
.resume = usb_serial_generic_resume,
};
static struct usb_serial_driver * const serial_drivers[] = {
&usb_serial_generic_device, NULL
};
#endif
int usb_serial_generic_register(void)
{
int retval = 0;
#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;
retval = usb_serial_register_drivers(serial_drivers,
"usbserial_generic", generic_device_ids);
#endif
return retval;
}
void usb_serial_generic_deregister(void)
{
#ifdef CONFIG_USB_SERIAL_GENERIC
usb_serial_deregister_drivers(serial_drivers);
#endif
}
int usb_serial_generic_open(struct tty_struct *tty, struct usb_serial_port *port)
{
int result = 0;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
port->throttled = 0;
port->throttle_req = 0;
spin_unlock_irqrestore(&port->lock, flags);
if (port->bulk_in_size)
result = usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
return result;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_open);
void usb_serial_generic_close(struct usb_serial_port *port)
{
unsigned long flags;
int i;
if (port->bulk_out_size) {
for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
usb_kill_urb(port->write_urbs[i]);
spin_lock_irqsave(&port->lock, flags);
kfifo_reset_out(&port->write_fifo);
spin_unlock_irqrestore(&port->lock, flags);
}
if (port->bulk_in_size) {
for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i)
usb_kill_urb(port->read_urbs[i]);
}
}
EXPORT_SYMBOL_GPL(usb_serial_generic_close);
int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
void *dest, size_t size)
{
return kfifo_out_locked(&port->write_fifo, dest, size, &port->lock);
}
/**
* usb_serial_generic_write_start - start writing buffered data
* @port: usb-serial port
* @mem_flags: flags to use for memory allocations
*
* Serialised using USB_SERIAL_WRITE_BUSY flag.
*
* Return: Zero on success or if busy, otherwise a negative errno value.
*/
static int usb_serial_generic_write_start(struct usb_serial_port *port,
gfp_t mem_flags)
{
struct urb *urb;
int count, result;
unsigned long flags;
int i;
if (test_and_set_bit_lock(USB_SERIAL_WRITE_BUSY, &port->flags))
return 0;
retry:
spin_lock_irqsave(&port->lock, flags);
if (!port->write_urbs_free || !kfifo_len(&port->write_fifo)) {
clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
spin_unlock_irqrestore(&port->lock, flags);
return 0;
}
i = (int)find_first_bit(&port->write_urbs_free,
ARRAY_SIZE(port->write_urbs));
spin_unlock_irqrestore(&port->lock, flags);
urb = port->write_urbs[i];
count = port->serial->type->prepare_write_buffer(port,
urb->transfer_buffer,
port->bulk_out_size);
urb->transfer_buffer_length = count;
usb_serial_debug_data(&port->dev, __func__, count, urb->transfer_buffer);
spin_lock_irqsave(&port->lock, flags);
port->tx_bytes += count;
spin_unlock_irqrestore(&port->lock, flags);
clear_bit(i, &port->write_urbs_free);
result = usb_submit_urb(urb, mem_flags);
if (result) {
dev_err_console(port, "%s - error submitting urb: %d\n",
__func__, result);
set_bit(i, &port->write_urbs_free);
spin_lock_irqsave(&port->lock, flags);
port->tx_bytes -= count;
spin_unlock_irqrestore(&port->lock, flags);
clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
return result;
}
/*
* Try sending off another urb, unless called from completion handler
* (in which case there will be no free urb or no data).
*/
if (mem_flags != GFP_ATOMIC)
goto retry;
clear_bit_unlock(USB_SERIAL_WRITE_BUSY, &port->flags);
return 0;
}
/**
* usb_serial_generic_write - generic write function
* @tty: tty for the port
* @port: usb-serial port
* @buf: data to write
* @count: number of bytes to write
*
* Return: The number of characters buffered, which may be anything from
* zero to @count, or a negative errno value.
*/
int usb_serial_generic_write(struct tty_struct *tty,
struct usb_serial_port *port, const unsigned char *buf, int count)
{
int result;
if (!port->bulk_out_size)
return -ENODEV;
if (!count)
return 0;
count = kfifo_in_locked(&port->write_fifo, buf, count, &port->lock);
result = usb_serial_generic_write_start(port, GFP_KERNEL);
if (result)
return result;
return count;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_write);
int usb_serial_generic_write_room(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
unsigned long flags;
int room;
if (!port->bulk_out_size)
return 0;
spin_lock_irqsave(&port->lock, flags);
room = kfifo_avail(&port->write_fifo);
spin_unlock_irqrestore(&port->lock, flags);
dev_dbg(&port->dev, "%s - returns %d\n", __func__, room);
return room;
}
int usb_serial_generic_chars_in_buffer(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
unsigned long flags;
int chars;
if (!port->bulk_out_size)
return 0;
spin_lock_irqsave(&port->lock, flags);
chars = kfifo_len(&port->write_fifo) + port->tx_bytes;
spin_unlock_irqrestore(&port->lock, flags);
dev_dbg(&port->dev, "%s - returns %d\n", __func__, chars);
return chars;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_chars_in_buffer);
void usb_serial_generic_wait_until_sent(struct tty_struct *tty, long timeout)
{
struct usb_serial_port *port = tty->driver_data;
unsigned int bps;
unsigned long period;
unsigned long expire;
bps = tty_get_baud_rate(tty);
if (!bps)
bps = 9600; /* B0 */
/*
* Use a poll-period of roughly the time it takes to send one
* character or at least one jiffy.
*/
period = max_t(unsigned long, (10 * HZ / bps), 1);
period = min_t(unsigned long, period, timeout);
dev_dbg(&port->dev, "%s - timeout = %u ms, period = %u ms\n",
__func__, jiffies_to_msecs(timeout),
jiffies_to_msecs(period));
expire = jiffies + timeout;
while (!port->serial->type->tx_empty(port)) {
schedule_timeout_interruptible(period);
if (signal_pending(current))
break;
if (time_after(jiffies, expire))
break;
}
}
EXPORT_SYMBOL_GPL(usb_serial_generic_wait_until_sent);
static int usb_serial_generic_submit_read_urb(struct usb_serial_port *port,
int index, gfp_t mem_flags)
{
int res;
if (!test_and_clear_bit(index, &port->read_urbs_free))
return 0;
dev_dbg(&port->dev, "%s - urb %d\n", __func__, index);
res = usb_submit_urb(port->read_urbs[index], mem_flags);
if (res) {
if (res != -EPERM) {
dev_err(&port->dev,
"%s - usb_submit_urb failed: %d\n",
__func__, res);
}
set_bit(index, &port->read_urbs_free);
return res;
}
return 0;
}
int usb_serial_generic_submit_read_urbs(struct usb_serial_port *port,
gfp_t mem_flags)
{
int res;
int i;
for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
res = usb_serial_generic_submit_read_urb(port, i, mem_flags);
if (res)
goto err;
}
return 0;
err:
for (; i >= 0; --i)
usb_kill_urb(port->read_urbs[i]);
return res;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_submit_read_urbs);
void usb_serial_generic_process_read_urb(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
char *ch = (char *)urb->transfer_buffer;
int i;
if (!urb->actual_length)
return;
/*
* The per character mucking around with sysrq path it too slow for
* stuff like 3G modems, so shortcircuit it in the 99.9999999% of
* cases where the USB serial is not a console anyway.
*/
if (!port->port.console || !port->sysrq)
tty_insert_flip_string(&port->port, ch, urb->actual_length);
else {
for (i = 0; i < urb->actual_length; i++, ch++) {
if (!usb_serial_handle_sysrq_char(port, *ch))
tty_insert_flip_char(&port->port, *ch, TTY_NORMAL);
}
}
tty_flip_buffer_push(&port->port);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_process_read_urb);
void usb_serial_generic_read_bulk_callback(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
unsigned char *data = urb->transfer_buffer;
unsigned long flags;
int i;
for (i = 0; i < ARRAY_SIZE(port->read_urbs); ++i) {
if (urb == port->read_urbs[i])
break;
}
set_bit(i, &port->read_urbs_free);
dev_dbg(&port->dev, "%s - urb %d, len %d\n", __func__, i,
urb->actual_length);
if (urb->status) {
dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
__func__, urb->status);
return;
}
usb_serial_debug_data(&port->dev, __func__, urb->actual_length, data);
port->serial->type->process_read_urb(urb);
/* Throttle the device if requested by tty */
spin_lock_irqsave(&port->lock, flags);
port->throttled = port->throttle_req;
if (!port->throttled) {
spin_unlock_irqrestore(&port->lock, flags);
usb_serial_generic_submit_read_urb(port, i, GFP_ATOMIC);
} else
spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
void usb_serial_generic_write_bulk_callback(struct urb *urb)
{
unsigned long flags;
struct usb_serial_port *port = urb->context;
int status = urb->status;
int i;
for (i = 0; i < ARRAY_SIZE(port->write_urbs); ++i)
if (port->write_urbs[i] == urb)
break;
spin_lock_irqsave(&port->lock, flags);
port->tx_bytes -= urb->transfer_buffer_length;
set_bit(i, &port->write_urbs_free);
spin_unlock_irqrestore(&port->lock, flags);
if (status) {
dev_dbg(&port->dev, "%s - non-zero urb status: %d\n",
__func__, status);
spin_lock_irqsave(&port->lock, flags);
kfifo_reset_out(&port->write_fifo);
spin_unlock_irqrestore(&port->lock, flags);
} else {
usb_serial_generic_write_start(port, GFP_ATOMIC);
}
usb_serial_port_softint(port);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
void usb_serial_generic_throttle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
port->throttle_req = 1;
spin_unlock_irqrestore(&port->lock, flags);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_throttle);
void usb_serial_generic_unthrottle(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
int was_throttled;
spin_lock_irq(&port->lock);
was_throttled = port->throttled;
port->throttled = port->throttle_req = 0;
spin_unlock_irq(&port->lock);
if (was_throttled)
usb_serial_generic_submit_read_urbs(port, GFP_KERNEL);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_unthrottle);
static bool usb_serial_generic_msr_changed(struct tty_struct *tty,
unsigned long arg, struct async_icount *cprev)
{
struct usb_serial_port *port = tty->driver_data;
struct async_icount cnow;
unsigned long flags;
bool ret;
/*
* Use tty-port initialised flag to detect all hangups including the
* one generated at USB-device disconnect.
*/
if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
return true;
spin_lock_irqsave(&port->lock, flags);
cnow = port->icount; /* atomic copy*/
spin_unlock_irqrestore(&port->lock, flags);
ret = ((arg & TIOCM_RNG) && (cnow.rng != cprev->rng)) ||
((arg & TIOCM_DSR) && (cnow.dsr != cprev->dsr)) ||
((arg & TIOCM_CD) && (cnow.dcd != cprev->dcd)) ||
((arg & TIOCM_CTS) && (cnow.cts != cprev->cts));
*cprev = cnow;
return ret;
}
int usb_serial_generic_tiocmiwait(struct tty_struct *tty, unsigned long arg)
{
struct usb_serial_port *port = tty->driver_data;
struct async_icount cnow;
unsigned long flags;
int ret;
spin_lock_irqsave(&port->lock, flags);
cnow = port->icount; /* atomic copy */
spin_unlock_irqrestore(&port->lock, flags);
ret = wait_event_interruptible(port->port.delta_msr_wait,
usb_serial_generic_msr_changed(tty, arg, &cnow));
if (!ret && !test_bit(ASYNCB_INITIALIZED, &port->port.flags))
ret = -EIO;
return ret;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_tiocmiwait);
int usb_serial_generic_get_icount(struct tty_struct *tty,
struct serial_icounter_struct *icount)
{
struct usb_serial_port *port = tty->driver_data;
struct async_icount cnow;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
cnow = port->icount; /* atomic copy */
spin_unlock_irqrestore(&port->lock, flags);
icount->cts = cnow.cts;
icount->dsr = cnow.dsr;
icount->rng = cnow.rng;
icount->dcd = cnow.dcd;
icount->tx = cnow.tx;
icount->rx = cnow.rx;
icount->frame = cnow.frame;
icount->parity = cnow.parity;
icount->overrun = cnow.overrun;
icount->brk = cnow.brk;
icount->buf_overrun = cnow.buf_overrun;
return 0;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_get_icount);
#ifdef CONFIG_MAGIC_SYSRQ
int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
{
if (port->sysrq && port->port.console) {
if (ch && time_before(jiffies, port->sysrq)) {
handle_sysrq(ch);
port->sysrq = 0;
return 1;
}
port->sysrq = 0;
}
return 0;
}
#else
int usb_serial_handle_sysrq_char(struct usb_serial_port *port, unsigned int ch)
{
return 0;
}
#endif
EXPORT_SYMBOL_GPL(usb_serial_handle_sysrq_char);
int usb_serial_handle_break(struct usb_serial_port *port)
{
if (!port->sysrq) {
port->sysrq = jiffies + HZ*5;
return 1;
}
port->sysrq = 0;
return 0;
}
EXPORT_SYMBOL_GPL(usb_serial_handle_break);
/**
* usb_serial_handle_dcd_change - handle a change of carrier detect state
* @port: usb-serial port
* @tty: tty for the port
* @status: new carrier detect status, nonzero if active
*/
void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
struct tty_struct *tty, unsigned int status)
{
struct tty_port *port = &usb_port->port;
dev_dbg(&usb_port->dev, "%s - status %d\n", __func__, status);
if (tty) {
struct tty_ldisc *ld = tty_ldisc_ref(tty);
if (ld) {
if (ld->ops->dcd_change)
ld->ops->dcd_change(tty, status);
tty_ldisc_deref(ld);
}
}
if (status)
wake_up_interruptible(&port->open_wait);
else if (tty && !C_CLOCAL(tty))
tty_hangup(tty);
}
EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
int usb_serial_generic_resume(struct usb_serial *serial)
{
struct usb_serial_port *port;
int i, c = 0, r;
for (i = 0; i < serial->num_ports; i++) {
port = serial->port[i];
if (!test_bit(ASYNCB_INITIALIZED, &port->port.flags))
continue;
if (port->bulk_in_size) {
r = usb_serial_generic_submit_read_urbs(port,
GFP_NOIO);
if (r < 0)
c++;
}
if (port->bulk_out_size) {
r = usb_serial_generic_write_start(port, GFP_NOIO);
if (r < 0)
c++;
}
}
return c ? -EIO : 0;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_resume);