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linux/drivers/usb/serial/empeg.c
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00

584 lines
15 KiB
C
Raw Blame History

/*
* USB Empeg empeg-car player driver
*
* Copyright (C) 2000, 2001
* Gary Brubaker (xavyer@ix.netcom.com)
*
* Copyright (C) 1999 - 2001
* 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, as published by
* the Free Software Foundation, version 2.
*
* See Documentation/usb/usb-serial.txt for more information on using this driver
*
* (07/16/2001) gb
* remove unused code in empeg_close() (thanks to Oliver Neukum for pointing this
* out) and rewrote empeg_set_termios().
*
* (05/30/2001) gkh
* switched from using spinlock to a semaphore, which fixes lots of problems.
*
* (04/08/2001) gb
* Identify version on module load.
*
* (01/22/2001) gb
* Added write_room() and chars_in_buffer() support.
*
* (12/21/2000) gb
* Moved termio stuff inside the port->active check.
* Moved MOD_DEC_USE_COUNT to end of empeg_close().
*
* (12/03/2000) gb
* Added port->tty->ldisc.set_termios(port->tty, NULL) to empeg_open()
* This notifies the tty driver that the termios have changed.
*
* (11/13/2000) gb
* Moved tty->low_latency = 1 from empeg_read_bulk_callback() to empeg_open()
* (It only needs to be set once - Doh!)
*
* (11/11/2000) gb
* Updated to work with id_table structure.
*
* (11/04/2000) gb
* Forked this from visor.c, and hacked it up to work with an
* Empeg ltd. empeg-car player. Constructive criticism welcomed.
* I would like to say, 'Thank You' to Greg Kroah-Hartman for the
* use of his code, and for his guidance, advice and patience. :)
* A 'Thank You' is in order for John Ripley of Empeg ltd for his
* advice, and patience too.
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <asm/uaccess.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
static int debug;
/*
* Version Information
*/
#define DRIVER_VERSION "v1.2"
#define DRIVER_AUTHOR "Greg Kroah-Hartman <greg@kroah.com>, Gary Brubaker <xavyer@ix.netcom.com>"
#define DRIVER_DESC "USB Empeg Mark I/II Driver"
#define EMPEG_VENDOR_ID 0x084f
#define EMPEG_PRODUCT_ID 0x0001
/* function prototypes for an empeg-car player */
static int empeg_open (struct usb_serial_port *port, struct file *filp);
static void empeg_close (struct usb_serial_port *port, struct file *filp);
static int empeg_write (struct usb_serial_port *port,
const unsigned char *buf,
int count);
static int empeg_write_room (struct usb_serial_port *port);
static int empeg_chars_in_buffer (struct usb_serial_port *port);
static void empeg_throttle (struct usb_serial_port *port);
static void empeg_unthrottle (struct usb_serial_port *port);
static int empeg_startup (struct usb_serial *serial);
static void empeg_shutdown (struct usb_serial *serial);
static int empeg_ioctl (struct usb_serial_port *port,
struct file * file,
unsigned int cmd,
unsigned long arg);
static void empeg_set_termios (struct usb_serial_port *port, struct termios *old_termios);
static void empeg_write_bulk_callback (struct urb *urb);
static void empeg_read_bulk_callback (struct urb *urb);
static struct usb_device_id id_table [] = {
{ USB_DEVICE(EMPEG_VENDOR_ID, EMPEG_PRODUCT_ID) },
{ } /* Terminating entry */
};
MODULE_DEVICE_TABLE (usb, id_table);
static struct usb_driver empeg_driver = {
.name = "empeg",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.id_table = id_table,
.no_dynamic_id = 1,
};
static struct usb_serial_driver empeg_device = {
.driver = {
.owner = THIS_MODULE,
.name = "empeg",
},
.id_table = id_table,
.num_interrupt_in = 0,
.num_bulk_in = 1,
.num_bulk_out = 1,
.num_ports = 1,
.open = empeg_open,
.close = empeg_close,
.throttle = empeg_throttle,
.unthrottle = empeg_unthrottle,
.attach = empeg_startup,
.shutdown = empeg_shutdown,
.ioctl = empeg_ioctl,
.set_termios = empeg_set_termios,
.write = empeg_write,
.write_room = empeg_write_room,
.chars_in_buffer = empeg_chars_in_buffer,
.write_bulk_callback = empeg_write_bulk_callback,
.read_bulk_callback = empeg_read_bulk_callback,
};
#define NUM_URBS 16
#define URB_TRANSFER_BUFFER_SIZE 4096
static struct urb *write_urb_pool[NUM_URBS];
static spinlock_t write_urb_pool_lock;
static int bytes_in;
static int bytes_out;
/******************************************************************************
* Empeg specific driver functions
******************************************************************************/
static int empeg_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 default termio settings */
empeg_set_termios (port, NULL) ;
bytes_in = 0;
bytes_out = 0;
/* 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,
empeg_read_bulk_callback,
port);
result = usb_submit_urb(port->read_urb, GFP_KERNEL);
if (result)
dev_err(&port->dev, "%s - failed submitting read urb, error %d\n", __FUNCTION__, result);
return result;
}
static void empeg_close (struct usb_serial_port *port, struct file * filp)
{
dbg("%s - port %d", __FUNCTION__, port->number);
/* shutdown our bulk read */
usb_kill_urb(port->read_urb);
/* Uncomment the following line if you want to see some statistics in your syslog */
/* dev_info (&port->dev, "Bytes In = %d Bytes Out = %d\n", bytes_in, bytes_out); */
}
static int empeg_write (struct usb_serial_port *port, const unsigned char *buf, int count)
{
struct usb_serial *serial = port->serial;
struct urb *urb;
const unsigned char *current_position = buf;
unsigned long flags;
int status;
int i;
int bytes_sent = 0;
int transfer_size;
dbg("%s - port %d", __FUNCTION__, port->number);
while (count > 0) {
/* try to find a free urb in our list of them */
urb = NULL;
spin_lock_irqsave (&write_urb_pool_lock, flags);
for (i = 0; i < NUM_URBS; ++i) {
if (write_urb_pool[i]->status != -EINPROGRESS) {
urb = write_urb_pool[i];
break;
}
}
spin_unlock_irqrestore (&write_urb_pool_lock, flags);
if (urb == NULL) {
dbg("%s - no more free urbs", __FUNCTION__);
goto exit;
}
if (urb->transfer_buffer == NULL) {
urb->transfer_buffer = kmalloc (URB_TRANSFER_BUFFER_SIZE, GFP_ATOMIC);
if (urb->transfer_buffer == NULL) {
dev_err(&port->dev, "%s no more kernel memory...\n", __FUNCTION__);
goto exit;
}
}
transfer_size = min (count, URB_TRANSFER_BUFFER_SIZE);
memcpy (urb->transfer_buffer, current_position, transfer_size);
usb_serial_debug_data(debug, &port->dev, __FUNCTION__, transfer_size, urb->transfer_buffer);
/* build up our urb */
usb_fill_bulk_urb (
urb,
serial->dev,
usb_sndbulkpipe(serial->dev,
port->bulk_out_endpointAddress),
urb->transfer_buffer,
transfer_size,
empeg_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);
bytes_sent = status;
break;
}
current_position += transfer_size;
bytes_sent += transfer_size;
count -= transfer_size;
bytes_out += transfer_size;
}
exit:
return bytes_sent;
}
static int empeg_write_room (struct usb_serial_port *port)
{
unsigned long flags;
int i;
int room = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave (&write_urb_pool_lock, flags);
/* tally up the number of bytes available */
for (i = 0; i < NUM_URBS; ++i) {
if (write_urb_pool[i]->status != -EINPROGRESS) {
room += URB_TRANSFER_BUFFER_SIZE;
}
}
spin_unlock_irqrestore (&write_urb_pool_lock, flags);
dbg("%s - returns %d", __FUNCTION__, room);
return (room);
}
static int empeg_chars_in_buffer (struct usb_serial_port *port)
{
unsigned long flags;
int i;
int chars = 0;
dbg("%s - port %d", __FUNCTION__, port->number);
spin_lock_irqsave (&write_urb_pool_lock, flags);
/* tally up the number of bytes waiting */
for (i = 0; i < NUM_URBS; ++i) {
if (write_urb_pool[i]->status == -EINPROGRESS) {
chars += URB_TRANSFER_BUFFER_SIZE;
}
}
spin_unlock_irqrestore (&write_urb_pool_lock, flags);
dbg("%s - returns %d", __FUNCTION__, chars);
return (chars);
}
static void empeg_write_bulk_callback (struct urb *urb)
{
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
dbg("%s - port %d", __FUNCTION__, port->number);
if (urb->status) {
dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
return;
}
usb_serial_port_softint(port);
}
static void empeg_read_bulk_callback (struct urb *urb)
{
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
struct tty_struct *tty;
unsigned char *data = urb->transfer_buffer;
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 (urb->actual_length) {
tty_buffer_request_room(tty, urb->actual_length);
tty_insert_flip_string(tty, data, urb->actual_length);
tty_flip_buffer_push(tty);
bytes_in += urb->actual_length;
}
/* Continue trying to always read */
usb_fill_bulk_urb(
port->read_urb,
port->serial->dev,
usb_rcvbulkpipe(port->serial->dev,
port->bulk_in_endpointAddress),
port->read_urb->transfer_buffer,
port->read_urb->transfer_buffer_length,
empeg_read_bulk_callback,
port);
result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
if (result)
dev_err(&urb->dev->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
return;
}
static void empeg_throttle (struct usb_serial_port *port)
{
dbg("%s - port %d", __FUNCTION__, port->number);
usb_kill_urb(port->read_urb);
}
static void empeg_unthrottle (struct usb_serial_port *port)
{
int result;
dbg("%s - port %d", __FUNCTION__, port->number);
port->read_urb->dev = port->serial->dev;
result = usb_submit_urb(port->read_urb, GFP_ATOMIC);
if (result)
dev_err(&port->dev, "%s - failed submitting read urb, error %d\n", __FUNCTION__, result);
return;
}
static int empeg_startup (struct usb_serial *serial)
{
int r;
dbg("%s", __FUNCTION__);
if (serial->dev->actconfig->desc.bConfigurationValue != 1) {
err("active config #%d != 1 ??",
serial->dev->actconfig->desc.bConfigurationValue);
return -ENODEV;
}
dbg("%s - reset config", __FUNCTION__);
r = usb_reset_configuration (serial->dev);
/* continue on with initialization */
return r;
}
static void empeg_shutdown (struct usb_serial *serial)
{
dbg ("%s", __FUNCTION__);
}
static int empeg_ioctl (struct usb_serial_port *port, struct file * file, unsigned int cmd, unsigned long arg)
{
dbg("%s - port %d, cmd 0x%.4x", __FUNCTION__, port->number, cmd);
return -ENOIOCTLCMD;
}
static void empeg_set_termios (struct usb_serial_port *port, struct termios *old_termios)
{
dbg("%s - port %d", __FUNCTION__, port->number);
if ((!port->tty) || (!port->tty->termios)) {
dbg("%s - no tty structures", __FUNCTION__);
return;
}
/*
* The empeg-car player wants these particular tty settings.
* You could, for example, change the baud rate, however the
* player only supports 115200 (currently), so there is really
* no point in support for changes to the tty settings.
* (at least for now)
*
* The default requirements for this device are:
*/
port->tty->termios->c_iflag
&= ~(IGNBRK /* disable ignore break */
| BRKINT /* disable break causes interrupt */
| PARMRK /* disable mark parity errors */
| ISTRIP /* disable clear high bit of input characters */
| INLCR /* disable translate NL to CR */
| IGNCR /* disable ignore CR */
| ICRNL /* disable translate CR to NL */
| IXON); /* disable enable XON/XOFF flow control */
port->tty->termios->c_oflag
&= ~OPOST; /* disable postprocess output characters */
port->tty->termios->c_lflag
&= ~(ECHO /* disable echo input characters */
| ECHONL /* disable echo new line */
| ICANON /* disable erase, kill, werase, and rprnt special characters */
| ISIG /* disable interrupt, quit, and suspend special characters */
| IEXTEN); /* disable non-POSIX special characters */
port->tty->termios->c_cflag
&= ~(CSIZE /* no size */
| PARENB /* disable parity bit */
| CBAUD); /* clear current baud rate */
port->tty->termios->c_cflag
|= (CS8 /* character size 8 bits */
| B115200); /* baud rate 115200 */
/*
* Force low_latency on; otherwise the pushes are scheduled;
* this is bad as it opens up the possibility of dropping bytes
* on the floor. We don't want to drop bytes on the floor. :)
*/
port->tty->low_latency = 1;
return;
}
static int __init empeg_init (void)
{
struct urb *urb;
int i, retval;
/* create our write urb pool and transfer buffers */
spin_lock_init (&write_urb_pool_lock);
for (i = 0; i < NUM_URBS; ++i) {
urb = usb_alloc_urb(0, GFP_KERNEL);
write_urb_pool[i] = urb;
if (urb == NULL) {
err("No more urbs???");
continue;
}
urb->transfer_buffer = kmalloc (URB_TRANSFER_BUFFER_SIZE, GFP_KERNEL);
if (!urb->transfer_buffer) {
err("%s - out of memory for urb buffers.",
__FUNCTION__);
continue;
}
}
retval = usb_serial_register(&empeg_device);
if (retval)
goto failed_usb_serial_register;
retval = usb_register(&empeg_driver);
if (retval)
goto failed_usb_register;
info(DRIVER_VERSION ":" DRIVER_DESC);
return 0;
failed_usb_register:
usb_serial_deregister(&empeg_device);
failed_usb_serial_register:
for (i = 0; i < NUM_URBS; ++i) {
if (write_urb_pool[i]) {
kfree(write_urb_pool[i]->transfer_buffer);
usb_free_urb(write_urb_pool[i]);
}
}
return retval;
}
static void __exit empeg_exit (void)
{
int i;
unsigned long flags;
usb_deregister(&empeg_driver);
usb_serial_deregister (&empeg_device);
spin_lock_irqsave (&write_urb_pool_lock, flags);
for (i = 0; i < NUM_URBS; ++i) {
if (write_urb_pool[i]) {
/* FIXME - uncomment the following usb_kill_urb call when
* the host controllers get fixed to set urb->dev = NULL after
* the urb is finished. Otherwise this call oopses. */
/* usb_kill_urb(write_urb_pool[i]); */
kfree(write_urb_pool[i]->transfer_buffer);
usb_free_urb (write_urb_pool[i]);
}
}
spin_unlock_irqrestore (&write_urb_pool_lock, flags);
}
module_init(empeg_init);
module_exit(empeg_exit);
MODULE_AUTHOR( DRIVER_AUTHOR );
MODULE_DESCRIPTION( DRIVER_DESC );
MODULE_LICENSE("GPL");
module_param(debug, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(debug, "Debug enabled or not");
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