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linux/drivers/usb/serial/ipw.c
Alan Cox 33f0f88f1c [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 08:01:59 -08:00

492 lines
14 KiB
C
Raw Blame History

/*
* IPWireless 3G UMTS TDD Modem driver (USB connected)
*
* Copyright (C) 2004 Roelf Diedericks <roelfd@inet.co.za>
* Copyright (C) 2004 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; either version 2 of the License, or
* (at your option) any later version.
*
* All information about the device was acquired using SnoopyPro
* on MSFT's O/S, and examing the MSFT drivers' debug output
* (insanely left _on_ in the enduser version)
*
* It was written out of frustration with the IPWireless USB modem
* supplied by Axity3G/Sentech South Africa not supporting
* Linux whatsoever.
*
* Nobody provided any proprietary information that was not already
* available for this device.
*
* The modem adheres to the "3GPP TS 27.007 AT command set for 3G
* User Equipment (UE)" standard, available from
* http://www.3gpp.org/ftp/Specs/html-info/27007.htm
*
* The code was only tested the IPWireless handheld modem distributed
* in South Africa by Sentech.
*
* It may work for Woosh Inc in .nz too, as it appears they use the
* same kit.
*
* There is still some work to be done in terms of handling
* DCD, DTR, RTS, CTS which are currently faked.
* It's good enough for PPP at this point. It's based off all kinds of
* code found in usb/serial and usb/class
*
*/
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/usb.h>
#include <asm/uaccess.h>
#include "usb-serial.h"
/*
* Version Information
*/
#define DRIVER_VERSION "v0.3"
#define DRIVER_AUTHOR "Roelf Diedericks"
#define DRIVER_DESC "IPWireless tty driver"
#define IPW_TTY_MAJOR 240 /* real device node major id, experimental range */
#define IPW_TTY_MINORS 256 /* we support 256 devices, dunno why, it'd be insane :) */
#define USB_IPW_MAGIC 0x6d02 /* magic number for ipw struct */
/* Message sizes */
#define EVENT_BUFFER_SIZE 0xFF
#define CHAR2INT16(c1,c0) (((u32)((c1) & 0xff) << 8) + (u32)((c0) & 0xff))
#define NUM_BULK_URBS 24
#define NUM_CONTROL_URBS 16
/* vendor/product pairs that are known work with this driver*/
#define IPW_VID 0x0bc3
#define IPW_PID 0x0001
/* Vendor commands: */
/* baud rates */
enum {
ipw_sio_b256000 = 0x000e,
ipw_sio_b128000 = 0x001d,
ipw_sio_b115200 = 0x0020,
ipw_sio_b57600 = 0x0040,
ipw_sio_b56000 = 0x0042,
ipw_sio_b38400 = 0x0060,
ipw_sio_b19200 = 0x00c0,
ipw_sio_b14400 = 0x0100,
ipw_sio_b9600 = 0x0180,
ipw_sio_b4800 = 0x0300,
ipw_sio_b2400 = 0x0600,
ipw_sio_b1200 = 0x0c00,
ipw_sio_b600 = 0x1800
};
/* data bits */
#define ipw_dtb_7 0x700
#define ipw_dtb_8 0x810 // ok so the define is misleading, I know, but forces 8,n,1
// I mean, is there a point to any other setting these days? :)
/* usb control request types : */
#define IPW_SIO_RXCTL 0x00 // control bulk rx channel transmissions, value=1/0 (on/off)
#define IPW_SIO_SET_BAUD 0x01 // set baud, value=requested ipw_sio_bxxxx
#define IPW_SIO_SET_LINE 0x03 // set databits, parity. value=ipw_dtb_x
#define IPW_SIO_SET_PIN 0x03 // set/clear dtr/rts value=ipw_pin_xxx
#define IPW_SIO_POLL 0x08 // get serial port status byte, call with value=0
#define IPW_SIO_INIT 0x11 // initializes ? value=0 (appears as first thing todo on open)
#define IPW_SIO_PURGE 0x12 // purge all transmissions?, call with value=numchar_to_purge
#define IPW_SIO_HANDFLOW 0x13 // set xon/xoff limits value=0, and a buffer of 0x10 bytes
#define IPW_SIO_SETCHARS 0x13 // set the flowcontrol special chars, value=0, buf=6 bytes,
// last 2 bytes contain flowcontrol chars e.g. 00 00 00 00 11 13
/* values used for request IPW_SIO_SET_PIN */
#define IPW_PIN_SETDTR 0x101
#define IPW_PIN_SETRTS 0x202
#define IPW_PIN_CLRDTR 0x100
#define IPW_PIN_CLRRTS 0x200 // unconfirmed
/* values used for request IPW_SIO_RXCTL */
#define IPW_RXBULK_ON 1
#define IPW_RXBULK_OFF 0
/* various 16 byte hardcoded transferbuffers used by flow control */
#define IPW_BYTES_FLOWINIT { 0x01, 0, 0, 0, 0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }
/* Interpretation of modem status lines */
/* These need sorting out by individually connecting pins and checking
* results. FIXME!
* When data is being sent we see 0x30 in the lower byte; this must
* contain DSR and CTS ...
*/
#define IPW_DSR ((1<<4) | (1<<5))
#define IPW_CTS ((1<<5) | (1<<4))
#define IPW_WANTS_TO_SEND 0x30
//#define IPW_DTR /* Data Terminal Ready */
//#define IPW_CTS /* Clear To Send */
//#define IPW_CD /* Carrier Detect */
//#define IPW_DSR /* Data Set Ready */
//#define IPW_RxD /* Receive pin */
//#define IPW_LE
//#define IPW_RTS
//#define IPW_ST
//#define IPW_SR
//#define IPW_RI /* Ring Indicator */
static struct usb_device_id usb_ipw_ids[] = {
{ USB_DEVICE(IPW_VID, IPW_PID) },
{ },
};
MODULE_DEVICE_TABLE(usb, usb_ipw_ids);
static struct usb_driver usb_ipw_driver = {
.name = "ipwtty",
.probe = usb_serial_probe,
.disconnect = usb_serial_disconnect,
.id_table = usb_ipw_ids,
.no_dynamic_id = 1,
};
static int debug;
static void ipw_read_bulk_callback(struct urb *urb, struct pt_regs *regs)
{
struct usb_serial_port *port = urb->context;
unsigned char *data = urb->transfer_buffer;
struct tty_struct *tty;
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) {
tty_buffer_request_room(tty, urb->actual_length);
tty_insert_flip_string(tty, data, urb->actual_length);
tty_flip_buffer_push(tty);
}
/* 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,
ipw_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);
return;
}
static int ipw_open(struct usb_serial_port *port, struct file *filp)
{
struct usb_device *dev = port->serial->dev;
u8 buf_flow_static[16] = IPW_BYTES_FLOWINIT;
u8 *buf_flow_init;
int result;
dbg("%s", __FUNCTION__);
buf_flow_init = kmalloc(16, GFP_KERNEL);
if (!buf_flow_init)
return -ENOMEM;
memcpy(buf_flow_init, buf_flow_static, 16);
if (port->tty)
port->tty->low_latency = 1;
/* --1: Tell the modem to initialize (we think) From sniffs this is always the
* first thing that gets sent to the modem during opening of the device */
dbg("%s: Sending SIO_INIT (we guess)",__FUNCTION__);
result = usb_control_msg(dev, usb_sndctrlpipe(dev,0),
IPW_SIO_INIT,
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
0,
0, /* index */
NULL,
0,
100000);
if (result < 0)
dev_err(&port->dev, "Init of modem failed (error = %d)", result);
/* reset the bulk pipes */
usb_clear_halt(dev, usb_rcvbulkpipe(dev, port->bulk_in_endpointAddress));
usb_clear_halt(dev, usb_sndbulkpipe(dev, port->bulk_out_endpointAddress));
/*--2: Start reading from the device */
dbg("%s: setting up bulk read callback",__FUNCTION__);
usb_fill_bulk_urb(port->read_urb, dev,
usb_rcvbulkpipe(dev, port->bulk_in_endpointAddress),
port->bulk_in_buffer,
port->bulk_in_size,
ipw_read_bulk_callback, port);
result = usb_submit_urb(port->read_urb, GFP_KERNEL);
if (result < 0)
dbg("%s - usb_submit_urb(read bulk) failed with status %d", __FUNCTION__, result);
/*--3: Tell the modem to open the floodgates on the rx bulk channel */
dbg("%s:asking modem for RxRead (RXBULK_ON)",__FUNCTION__);
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_RXCTL,
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
IPW_RXBULK_ON,
0, /* index */
NULL,
0,
100000);
if (result < 0)
dev_err(&port->dev, "Enabling bulk RxRead failed (error = %d)", result);
/*--4: setup the initial flowcontrol */
dbg("%s:setting init flowcontrol (%s)",__FUNCTION__,buf_flow_init);
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_HANDFLOW,
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
0,
0,
buf_flow_init,
0x10,
200000);
if (result < 0)
dev_err(&port->dev, "initial flowcontrol failed (error = %d)", result);
/*--5: raise the dtr */
dbg("%s:raising dtr",__FUNCTION__);
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_SET_PIN,
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
IPW_PIN_SETDTR,
0,
NULL,
0,
200000);
if (result < 0)
dev_err(&port->dev, "setting dtr failed (error = %d)", result);
/*--6: raise the rts */
dbg("%s:raising rts",__FUNCTION__);
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_SET_PIN,
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
IPW_PIN_SETRTS,
0,
NULL,
0,
200000);
if (result < 0)
dev_err(&port->dev, "setting dtr failed (error = %d)", result);
kfree(buf_flow_init);
return 0;
}
static void ipw_close(struct usb_serial_port *port, struct file * filp)
{
struct usb_device *dev = port->serial->dev;
int result;
if (tty_hung_up_p(filp)) {
dbg("%s: tty_hung_up_p ...", __FUNCTION__);
return;
}
/*--1: drop the dtr */
dbg("%s:dropping dtr",__FUNCTION__);
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_SET_PIN,
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
IPW_PIN_CLRDTR,
0,
NULL,
0,
200000);
if (result < 0)
dev_err(&port->dev, "dropping dtr failed (error = %d)", result);
/*--2: drop the rts */
dbg("%s:dropping rts",__FUNCTION__);
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_SET_PIN, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
IPW_PIN_CLRRTS,
0,
NULL,
0,
200000);
if (result < 0)
dev_err(&port->dev, "dropping rts failed (error = %d)", result);
/*--3: purge */
dbg("%s:sending purge",__FUNCTION__);
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_PURGE, USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
0x03,
0,
NULL,
0,
200000);
if (result < 0)
dev_err(&port->dev, "purge failed (error = %d)", result);
/* send RXBULK_off (tell modem to stop transmitting bulk data on rx chan) */
result = usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
IPW_SIO_RXCTL,
USB_TYPE_VENDOR | USB_RECIP_INTERFACE | USB_DIR_OUT,
IPW_RXBULK_OFF,
0, /* index */
NULL,
0,
100000);
if (result < 0)
dev_err(&port->dev, "Disabling bulk RxRead failed (error = %d)", result);
/* shutdown any in-flight urbs that we know about */
usb_kill_urb(port->read_urb);
usb_kill_urb(port->write_urb);
}
static void ipw_write_bulk_callback(struct urb *urb, struct pt_regs *regs)
{
struct usb_serial_port *port = urb->context;
dbg("%s", __FUNCTION__);
if (urb->status)
dbg("%s - nonzero write bulk status received: %d", __FUNCTION__, urb->status);
schedule_work(&port->work);
}
static int ipw_write(struct usb_serial_port *port, const unsigned char *buf, int count)
{
struct usb_device *dev = port->serial->dev;
int ret;
dbg("%s: TOP: count=%d, in_interrupt=%ld", __FUNCTION__,
count, in_interrupt() );
if (count == 0) {
dbg("%s - write request of 0 bytes", __FUNCTION__);
return 0;
}
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 = min(count, port->bulk_out_size);
memcpy(port->bulk_out_buffer, buf, count);
dbg("%s count now:%d", __FUNCTION__, count);
usb_fill_bulk_urb(port->write_urb, dev,
usb_sndbulkpipe(dev, port->bulk_out_endpointAddress),
port->write_urb->transfer_buffer,
count,
ipw_write_bulk_callback,
port);
ret = usb_submit_urb(port->write_urb, GFP_ATOMIC);
if (ret != 0) {
port->write_urb_busy = 0;
dbg("%s - usb_submit_urb(write bulk) failed with error = %d", __FUNCTION__, ret);
return ret;
}
dbg("%s returning %d", __FUNCTION__, count);
return count;
}
static int ipw_probe(struct usb_serial_port *port)
{
return 0;
}
static int ipw_disconnect(struct usb_serial_port *port)
{
usb_set_serial_port_data(port, NULL);
return 0;
}
static struct usb_serial_driver ipw_device = {
.driver = {
.owner = THIS_MODULE,
.name = "ipw",
},
.description = "IPWireless converter",
.id_table = usb_ipw_ids,
.num_interrupt_in = NUM_DONT_CARE,
.num_bulk_in = 1,
.num_bulk_out = 1,
.num_ports = 1,
.open = ipw_open,
.close = ipw_close,
.port_probe = ipw_probe,
.port_remove = ipw_disconnect,
.write = ipw_write,
.write_bulk_callback = ipw_write_bulk_callback,
.read_bulk_callback = ipw_read_bulk_callback,
};
static int usb_ipw_init(void)
{
int retval;
retval = usb_serial_register(&ipw_device);
if (retval)
return retval;
retval = usb_register(&usb_ipw_driver);
if (retval) {
usb_serial_deregister(&ipw_device);
return retval;
}
info(DRIVER_DESC " " DRIVER_VERSION);
return 0;
}
static void usb_ipw_exit(void)
{
usb_deregister(&usb_ipw_driver);
usb_serial_deregister(&ipw_device);
}
module_init(usb_ipw_init);
module_exit(usb_ipw_exit);
/* Module information */
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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