linux/drivers/usb/serial/generic.c

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/*
* 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/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 <linux/usb/serial.h>
#include <asm/uaccess.h>
static int debug;
#ifdef CONFIG_USB_SERIAL_GENERIC
static int generic_probe(struct usb_interface *interface,
const struct usb_device_id *id);
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. */
/* 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 struct usb_driver generic_driver = {
.name = "usbserial_generic",
.probe = generic_probe,
.disconnect = usb_serial_disconnect,
.id_table = generic_serial_ids,
.no_dynamic_id = 1,
};
/* All of the device info needed for the Generic Serial Converter */
struct usb_serial_driver usb_serial_generic_device = {
.driver = {
.owner = THIS_MODULE,
.name = "generic",
},
.id_table = generic_device_ids,
.usb_driver = &generic_driver,
.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,
.throttle = usb_serial_generic_throttle,
.unthrottle = usb_serial_generic_unthrottle,
};
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;
}
#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;
unsigned long flags;
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;
/* clear the throttle flags */
spin_lock_irqsave(&port->lock, flags);
port->throttled = 0;
port->throttle_req = 0;
spin_unlock_irqrestore(&port->lock, flags);
/* if we have a bulk endpoint, 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;
}
EXPORT_SYMBOL_GPL(usb_serial_generic_open);
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_bh(&port->lock);
if (port->write_urb_busy) {
spin_unlock_bh(&port->lock);
dbg("%s - already writing", __FUNCTION__);
return 0;
}
port->write_urb_busy = 1;
spin_unlock_bh(&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);
}
/* Push data to tty layer and resubmit the bulk read URB */
static void flush_and_resubmit_read_urb (struct usb_serial_port *port)
{
struct usb_serial *serial = port->serial;
struct urb *urb = port->read_urb;
struct tty_struct *tty = port->tty;
int result;
/* Push data to tty */
if (tty && urb->actual_length) {
[PATCH] TTY layer buffering revamp The API and code have been through various bits of initial review by serial driver people but they definitely need to live somewhere for a while so the unconverted drivers can get knocked into shape, existing drivers that have been updated can be better tuned and bugs whacked out. This replaces the tty flip buffers with kmalloc objects in rings. In the normal situation for an IRQ driven serial port at typical speeds the behaviour is pretty much the same, two buffers end up allocated and the kernel cycles between them as before. When there are delays or at high speed we now behave far better as the buffer pool can grow a bit rather than lose characters. This also means that we can operate at higher speeds reliably. For drivers that receive characters in blocks (DMA based, USB and especially virtualisation) the layer allows a lot of driver specific code that works around the tty layer with private secondary queues to be removed. The IBM folks need this sort of layer, the smart serial port people do, the virtualisers do (because a virtualised tty typically operates at infinite speed rather than emulating 9600 baud). Finally many drivers had invalid and unsafe attempts to avoid buffer overflows by directly invoking tty methods extracted out of the innards of work queue structs. These are no longer needed and all go away. That fixes various random hangs with serial ports on overflow. The other change in here is to optimise the receive_room path that is used by some callers. It turns out that only one ldisc uses receive room except asa constant and it updates it far far less than the value is read. We thus make it a variable not a function call. I expect the code to contain bugs due to the size alone but I'll be watching and squashing them and feeding out new patches as it goes. Because the buffers now dynamically expand you should only run out of buffering when the kernel runs out of memory for real. That means a lot of the horrible hacks high performance drivers used to do just aren't needed any more. Description: tty_insert_flip_char is an old API and continues to work as before, as does tty_flip_buffer_push() [this is why many drivers dont need modification]. It does now also return the number of chars inserted There are also tty_buffer_request_room(tty, len) which asks for a buffer block of the length requested and returns the space found. This improves efficiency with hardware that knows how much to transfer. and tty_insert_flip_string_flags(tty, str, flags, len) to insert a string of characters and flags For a smart interface the usual code is len = tty_request_buffer_room(tty, amount_hardware_says); tty_insert_flip_string(tty, buffer_from_card, len); More description! At the moment tty buffers are attached directly to the tty. This is causing a lot of the problems related to tty layer locking, also problems at high speed and also with bursty data (such as occurs in virtualised environments) I'm working on ripping out the flip buffers and replacing them with a pool of dynamically allocated buffers. This allows both for old style "byte I/O" devices and also helps virtualisation and smart devices where large blocks of data suddenely materialise and need storing. So far so good. Lots of drivers reference tty->flip.*. Several of them also call directly and unsafely into function pointers it provides. This will all break. Most drivers can use tty_insert_flip_char which can be kept as an API but others need more. At the moment I've added the following interfaces, if people think more will be needed now is a good time to say int tty_buffer_request_room(tty, size) Try and ensure at least size bytes are available, returns actual room (may be zero). At the moment it just uses the flipbuf space but that will change. Repeated calls without characters being added are not cumulative. (ie if you call it with 1, 1, 1, and then 4 you'll have four characters of space. The other functions will also try and grow buffers in future but this will be a more efficient way when you know block sizes. int tty_insert_flip_char(tty, ch, flag) As before insert a character if there is room. Now returns 1 for success, 0 for failure. int tty_insert_flip_string(tty, str, len) Insert a block of non error characters. Returns the number inserted. int tty_prepare_flip_string(tty, strptr, len) Adjust the buffer to allow len characters to be added. Returns a buffer pointer in strptr and the length available. This allows for hardware that needs to use functions like insl or mencpy_fromio. Signed-off-by: Alan Cox <alan@redhat.com> Cc: Paul Fulghum <paulkf@microgate.com> Signed-off-by: Hirokazu Takata <takata@linux-m32r.org> Signed-off-by: Serge Hallyn <serue@us.ibm.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-01-10 04:54:13 +00:00
tty_buffer_request_room(tty, urb->actual_length);
tty_insert_flip_string(tty, urb->transfer_buffer, urb->actual_length);
tty_flip_buffer_push(tty); /* is this allowed from an URB callback ? */
}
/* Continue reading from 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_ATOMIC);
if (result)
dev_err(&port->dev, "%s - failed resubmitting read urb, error %d\n", __FUNCTION__, result);
}
void usb_serial_generic_read_bulk_callback (struct urb *urb)
{
struct usb_serial_port *port = (struct usb_serial_port *)urb->context;
unsigned char *data = urb->transfer_buffer;
int is_throttled;
unsigned long flags;
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);
/* Throttle the device if requested by tty */
if (urb->actual_length) {
spin_lock_irqsave(&port->lock, flags);
is_throttled = port->throttled = port->throttle_req;
spin_unlock_irqrestore(&port->lock, flags);
if (is_throttled) {
/* Let the received data linger in the read URB;
* usb_serial_generic_unthrottle() will pick it
* up later. */
dbg("%s - throttling device", __FUNCTION__);
return;
}
}
/* Handle data and continue reading from device */
flush_and_resubmit_read_urb(port);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_read_bulk_callback);
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 13:55:46 +00:00
void usb_serial_generic_write_bulk_callback (struct urb *urb)
{
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(port);
}
EXPORT_SYMBOL_GPL(usb_serial_generic_write_bulk_callback);
void usb_serial_generic_throttle (struct usb_serial_port *port)
{
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
/* Set the throttle request flag. It will be picked up
* by usb_serial_generic_read_bulk_callback(). */
spin_lock_irqsave(&port->lock, flags);
port->throttle_req = 1;
spin_unlock_irqrestore(&port->lock, flags);
}
void usb_serial_generic_unthrottle (struct usb_serial_port *port)
{
int was_throttled;
unsigned long flags;
dbg("%s - port %d", __FUNCTION__, port->number);
/* Clear the throttle flags */
spin_lock_irqsave(&port->lock, flags);
was_throttled = port->throttled;
port->throttled = port->throttle_req = 0;
spin_unlock_irqrestore(&port->lock, flags);
if (was_throttled) {
/* Handle pending data and resume reading from device */
flush_and_resubmit_read_urb(port);
}
}
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]);
}
}