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linux-next/drivers/char/n_r3964.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

1409 lines
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C
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/* r3964 linediscipline for linux
*
* -----------------------------------------------------------
* Copyright by
* Philips Automation Projects
* Kassel (Germany)
* http://www.pap-philips.de
* -----------------------------------------------------------
* This software may be used and distributed according to the terms of
* the GNU General Public License, incorporated herein by reference.
*
* Author:
* L. Haag
*
* $Log: n_r3964.c,v $
* Revision 1.10 2001/03/18 13:02:24 dwmw2
* Fix timer usage, use spinlocks properly.
*
* Revision 1.9 2001/03/18 12:52:14 dwmw2
* Merge changes in 2.4.2
*
* Revision 1.8 2000/03/23 14:14:54 dwmw2
* Fix race in sleeping in r3964_read()
*
* Revision 1.7 1999/28/08 11:41:50 dwmw2
* Port to 2.3 kernel
*
* Revision 1.6 1998/09/30 00:40:40 dwmw2
* Fixed compilation on 2.0.x kernels
* Updated to newly registered tty-ldisc number 9
*
* Revision 1.5 1998/09/04 21:57:36 dwmw2
* Signal handling bug fixes, port to 2.1.x.
*
* Revision 1.4 1998/04/02 20:26:59 lhaag
* select, blocking, ...
*
* Revision 1.3 1998/02/12 18:58:43 root
* fixed some memory leaks
* calculation of checksum characters
*
* Revision 1.2 1998/02/07 13:03:34 root
* ioctl read_telegram
*
* Revision 1.1 1998/02/06 19:21:03 root
* Initial revision
*
*
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/errno.h>
#include <linux/string.h> /* used in new tty drivers */
#include <linux/signal.h> /* used in new tty drivers */
#include <linux/ioctl.h>
#include <linux/n_r3964.h>
#include <linux/poll.h>
#include <linux/init.h>
#include <asm/uaccess.h>
//#define DEBUG_QUEUE
/* Log successful handshake and protocol operations */
//#define DEBUG_PROTO_S
/* Log handshake and protocol errors: */
//#define DEBUG_PROTO_E
/* Log Linediscipline operations (open, close, read, write...): */
//#define DEBUG_LDISC
/* Log module and memory operations (init, cleanup; kmalloc, kfree): */
//#define DEBUG_MODUL
/* Macro helpers for debug output: */
#define TRACE(format, args...) printk("r3964: " format "\n" , ## args);
#ifdef DEBUG_MODUL
#define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args);
#else
#define TRACE_M(fmt, arg...) /**/
#endif
#ifdef DEBUG_PROTO_S
#define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args);
#else
#define TRACE_PS(fmt, arg...) /**/
#endif
#ifdef DEBUG_PROTO_E
#define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args);
#else
#define TRACE_PE(fmt, arg...) /**/
#endif
#ifdef DEBUG_LDISC
#define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args);
#else
#define TRACE_L(fmt, arg...) /**/
#endif
#ifdef DEBUG_QUEUE
#define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args);
#else
#define TRACE_Q(fmt, arg...) /**/
#endif
static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
static void put_char(struct r3964_info *pInfo, unsigned char ch);
static void trigger_transmit(struct r3964_info *pInfo);
static void retry_transmit(struct r3964_info *pInfo);
static void transmit_block(struct r3964_info *pInfo);
static void receive_char(struct r3964_info *pInfo, const unsigned char c);
static void receive_error(struct r3964_info *pInfo, const char flag);
static void on_timeout(unsigned long priv);
static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg);
static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char __user *buf);
static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
int error_code, struct r3964_block_header *pBlock);
static struct r3964_message* remove_msg(struct r3964_info *pInfo,
struct r3964_client_info *pClient);
static void remove_client_block(struct r3964_info *pInfo,
struct r3964_client_info *pClient);
static int r3964_open(struct tty_struct *tty);
static void r3964_close(struct tty_struct *tty);
static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
unsigned char __user *buf, size_t nr);
static ssize_t r3964_write(struct tty_struct * tty, struct file * file,
const unsigned char * buf, size_t nr);
static int r3964_ioctl(struct tty_struct * tty, struct file * file,
unsigned int cmd, unsigned long arg);
static void r3964_set_termios(struct tty_struct *tty, struct termios * old);
static unsigned int r3964_poll(struct tty_struct * tty, struct file * file,
struct poll_table_struct *wait);
static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
char *fp, int count);
static struct tty_ldisc tty_ldisc_N_R3964 = {
.owner = THIS_MODULE,
.magic = TTY_LDISC_MAGIC,
.name = "R3964",
.open = r3964_open,
.close = r3964_close,
.read = r3964_read,
.write = r3964_write,
.ioctl = r3964_ioctl,
.set_termios = r3964_set_termios,
.poll = r3964_poll,
.receive_buf = r3964_receive_buf,
};
static void dump_block(const unsigned char *block, unsigned int length)
{
unsigned int i,j;
char linebuf[16*3+1];
for(i=0;i<length;i+=16)
{
for(j=0;(j<16) && (j+i<length);j++)
{
sprintf(linebuf+3*j,"%02x ",block[i+j]);
}
linebuf[3*j]='\0';
TRACE_PS("%s",linebuf);
}
}
/*************************************************************
* Driver initialisation
*************************************************************/
/*************************************************************
* Module support routines
*************************************************************/
static void __exit r3964_exit(void)
{
int status;
TRACE_M ("cleanup_module()");
status=tty_unregister_ldisc(N_R3964);
if(status!=0)
{
printk(KERN_ERR "r3964: error unregistering linediscipline: %d\n", status);
}
else
{
TRACE_L("linediscipline successfully unregistered");
}
}
static int __init r3964_init(void)
{
int status;
printk ("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
/*
* Register the tty line discipline
*/
status = tty_register_ldisc (N_R3964, &tty_ldisc_N_R3964);
if (status == 0)
{
TRACE_L("line discipline %d registered", N_R3964);
TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
tty_ldisc_N_R3964.num);
TRACE_L("open=%p", tty_ldisc_N_R3964.open);
TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
}
else
{
printk (KERN_ERR "r3964: error registering line discipline: %d\n", status);
}
return status;
}
module_init(r3964_init);
module_exit(r3964_exit);
/*************************************************************
* Protocol implementation routines
*************************************************************/
static void add_tx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
{
unsigned long flags;
spin_lock_irqsave(&pInfo->lock, flags);
pHeader->next = NULL;
if(pInfo->tx_last == NULL)
{
pInfo->tx_first = pInfo->tx_last = pHeader;
}
else
{
pInfo->tx_last->next = pHeader;
pInfo->tx_last = pHeader;
}
spin_unlock_irqrestore(&pInfo->lock, flags);
TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
pHeader, pHeader->length, pInfo->tx_first );
}
static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
{
struct r3964_block_header *pHeader;
unsigned long flags;
#ifdef DEBUG_QUEUE
struct r3964_block_header *pDump;
#endif
pHeader = pInfo->tx_first;
if(pHeader==NULL)
return;
#ifdef DEBUG_QUEUE
printk("r3964: remove_from_tx_queue: %p, length %u - ",
pHeader, pHeader->length );
for(pDump=pHeader;pDump;pDump=pDump->next)
printk("%p ", pDump);
printk("\n");
#endif
if(pHeader->owner)
{
if(error_code)
{
add_msg(pHeader->owner, R3964_MSG_ACK, 0,
error_code, NULL);
}
else
{
add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
error_code, NULL);
}
wake_up_interruptible (&pInfo->read_wait);
}
spin_lock_irqsave(&pInfo->lock, flags);
pInfo->tx_first = pHeader->next;
if(pInfo->tx_first==NULL)
{
pInfo->tx_last = NULL;
}
spin_unlock_irqrestore(&pInfo->lock, flags);
kfree(pHeader);
TRACE_M("remove_from_tx_queue - kfree %p",pHeader);
TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
pInfo->tx_first, pInfo->tx_last );
}
static void add_rx_queue(struct r3964_info *pInfo, struct r3964_block_header *pHeader)
{
unsigned long flags;
spin_lock_irqsave(&pInfo->lock, flags);
pHeader->next = NULL;
if(pInfo->rx_last == NULL)
{
pInfo->rx_first = pInfo->rx_last = pHeader;
}
else
{
pInfo->rx_last->next = pHeader;
pInfo->rx_last = pHeader;
}
pInfo->blocks_in_rx_queue++;
spin_unlock_irqrestore(&pInfo->lock, flags);
TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
pHeader, pHeader->length,
pInfo->rx_first, pInfo->blocks_in_rx_queue);
}
static void remove_from_rx_queue(struct r3964_info *pInfo,
struct r3964_block_header *pHeader)
{
unsigned long flags;
struct r3964_block_header *pFind;
if(pHeader==NULL)
return;
TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue );
TRACE_Q("remove_from_rx_queue: %p, length %u",
pHeader, pHeader->length );
spin_lock_irqsave(&pInfo->lock, flags);
if(pInfo->rx_first == pHeader)
{
/* Remove the first block in the linked list: */
pInfo->rx_first = pHeader->next;
if(pInfo->rx_first==NULL)
{
pInfo->rx_last = NULL;
}
pInfo->blocks_in_rx_queue--;
}
else
{
/* Find block to remove: */
for(pFind=pInfo->rx_first; pFind; pFind=pFind->next)
{
if(pFind->next == pHeader)
{
/* Got it. */
pFind->next = pHeader->next;
pInfo->blocks_in_rx_queue--;
if(pFind->next==NULL)
{
/* Oh, removed the last one! */
pInfo->rx_last = pFind;
}
break;
}
}
}
spin_unlock_irqrestore(&pInfo->lock, flags);
kfree(pHeader);
TRACE_M("remove_from_rx_queue - kfree %p",pHeader);
TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue );
}
static void put_char(struct r3964_info *pInfo, unsigned char ch)
{
struct tty_struct *tty = pInfo->tty;
if(tty==NULL)
return;
if(tty->driver->put_char)
{
tty->driver->put_char(tty, ch);
}
pInfo->bcc ^= ch;
}
static void flush(struct r3964_info *pInfo)
{
struct tty_struct *tty = pInfo->tty;
if(tty==NULL)
return;
if(tty->driver->flush_chars)
{
tty->driver->flush_chars(tty);
}
}
static void trigger_transmit(struct r3964_info *pInfo)
{
unsigned long flags;
spin_lock_irqsave(&pInfo->lock, flags);
if((pInfo->state == R3964_IDLE) && (pInfo->tx_first!=NULL))
{
pInfo->state = R3964_TX_REQUEST;
pInfo->nRetry=0;
pInfo->flags &= ~R3964_ERROR;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
spin_unlock_irqrestore(&pInfo->lock, flags);
TRACE_PS("trigger_transmit - sent STX");
put_char(pInfo, STX);
flush(pInfo);
pInfo->bcc = 0;
}
else
{
spin_unlock_irqrestore(&pInfo->lock, flags);
}
}
static void retry_transmit(struct r3964_info *pInfo)
{
if(pInfo->nRetry<R3964_MAX_RETRIES)
{
TRACE_PE("transmission failed. Retry #%d",
pInfo->nRetry);
pInfo->bcc = 0;
put_char(pInfo, STX);
flush(pInfo);
pInfo->state = R3964_TX_REQUEST;
pInfo->nRetry++;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
}
else
{
TRACE_PE("transmission failed after %d retries",
R3964_MAX_RETRIES);
remove_from_tx_queue(pInfo, R3964_TX_FAIL);
put_char(pInfo, NAK);
flush(pInfo);
pInfo->state = R3964_IDLE;
trigger_transmit(pInfo);
}
}
static void transmit_block(struct r3964_info *pInfo)
{
struct tty_struct *tty = pInfo->tty;
struct r3964_block_header *pBlock = pInfo->tx_first;
int room=0;
if((tty==NULL) || (pBlock==NULL))
{
return;
}
if(tty->driver->write_room)
room=tty->driver->write_room(tty);
TRACE_PS("transmit_block %p, room %d, length %d",
pBlock, room, pBlock->length);
while(pInfo->tx_position < pBlock->length)
{
if(room<2)
break;
if(pBlock->data[pInfo->tx_position]==DLE)
{
/* send additional DLE char: */
put_char(pInfo, DLE);
}
put_char(pInfo, pBlock->data[pInfo->tx_position++]);
room--;
}
if((pInfo->tx_position == pBlock->length) && (room>=3))
{
put_char(pInfo, DLE);
put_char(pInfo, ETX);
if(pInfo->flags & R3964_BCC)
{
put_char(pInfo, pInfo->bcc);
}
pInfo->state = R3964_WAIT_FOR_TX_ACK;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
}
flush(pInfo);
}
static void on_receive_block(struct r3964_info *pInfo)
{
unsigned int length;
struct r3964_client_info *pClient;
struct r3964_block_header *pBlock;
length=pInfo->rx_position;
/* compare byte checksum characters: */
if(pInfo->flags & R3964_BCC)
{
if(pInfo->bcc!=pInfo->last_rx)
{
TRACE_PE("checksum error - got %x but expected %x",
pInfo->last_rx, pInfo->bcc);
pInfo->flags |= R3964_CHECKSUM;
}
}
/* check for errors (parity, overrun,...): */
if(pInfo->flags & R3964_ERROR)
{
TRACE_PE("on_receive_block - transmission failed error %x",
pInfo->flags & R3964_ERROR);
put_char(pInfo, NAK);
flush(pInfo);
if(pInfo->nRetry<R3964_MAX_RETRIES)
{
pInfo->state=R3964_WAIT_FOR_RX_REPEAT;
pInfo->nRetry++;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
}
else
{
TRACE_PE("on_receive_block - failed after max retries");
pInfo->state=R3964_IDLE;
}
return;
}
/* received block; submit DLE: */
put_char(pInfo, DLE);
flush(pInfo);
del_timer_sync(&pInfo->tmr);
TRACE_PS(" rx success: got %d chars", length);
/* prepare struct r3964_block_header: */
pBlock = kmalloc(length+sizeof(struct r3964_block_header), GFP_KERNEL);
TRACE_M("on_receive_block - kmalloc %p",pBlock);
if(pBlock==NULL)
return;
pBlock->length = length;
pBlock->data = ((unsigned char*)pBlock)+sizeof(struct r3964_block_header);
pBlock->locks = 0;
pBlock->next = NULL;
pBlock->owner = NULL;
memcpy(pBlock->data, pInfo->rx_buf, length);
/* queue block into rx_queue: */
add_rx_queue(pInfo, pBlock);
/* notify attached client processes: */
for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
{
if(pClient->sig_flags & R3964_SIG_DATA)
{
add_msg(pClient, R3964_MSG_DATA, length, R3964_OK, pBlock);
}
}
wake_up_interruptible (&pInfo->read_wait);
pInfo->state = R3964_IDLE;
trigger_transmit(pInfo);
}
static void receive_char(struct r3964_info *pInfo, const unsigned char c)
{
switch(pInfo->state)
{
case R3964_TX_REQUEST:
if(c==DLE)
{
TRACE_PS("TX_REQUEST - got DLE");
pInfo->state = R3964_TRANSMITTING;
pInfo->tx_position = 0;
transmit_block(pInfo);
}
else if(c==STX)
{
if(pInfo->nRetry==0)
{
TRACE_PE("TX_REQUEST - init conflict");
if(pInfo->priority == R3964_SLAVE)
{
goto start_receiving;
}
}
else
{
TRACE_PE("TX_REQUEST - secondary init conflict!?"
" Switching to SLAVE mode for next rx.");
goto start_receiving;
}
}
else
{
TRACE_PE("TX_REQUEST - char != DLE: %x", c);
retry_transmit(pInfo);
}
break;
case R3964_TRANSMITTING:
if(c==NAK)
{
TRACE_PE("TRANSMITTING - got NAK");
retry_transmit(pInfo);
}
else
{
TRACE_PE("TRANSMITTING - got invalid char");
pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
}
break;
case R3964_WAIT_FOR_TX_ACK:
if(c==DLE)
{
TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
remove_from_tx_queue(pInfo, R3964_OK);
pInfo->state = R3964_IDLE;
trigger_transmit(pInfo);
}
else
{
retry_transmit(pInfo);
}
break;
case R3964_WAIT_FOR_RX_REPEAT:
/* FALLTROUGH */
case R3964_IDLE:
if(c==STX)
{
/* Prevent rx_queue from overflow: */
if(pInfo->blocks_in_rx_queue >= R3964_MAX_BLOCKS_IN_RX_QUEUE)
{
TRACE_PE("IDLE - got STX but no space in rx_queue!");
pInfo->state=R3964_WAIT_FOR_RX_BUF;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_NO_BUF);
break;
}
start_receiving:
/* Ok, start receiving: */
TRACE_PS("IDLE - got STX");
pInfo->rx_position = 0;
pInfo->last_rx = 0;
pInfo->flags &= ~R3964_ERROR;
pInfo->state=R3964_RECEIVING;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
pInfo->nRetry = 0;
put_char(pInfo, DLE);
flush(pInfo);
pInfo->bcc = 0;
}
break;
case R3964_RECEIVING:
if(pInfo->rx_position < RX_BUF_SIZE)
{
pInfo->bcc ^= c;
if(c==DLE)
{
if(pInfo->last_rx==DLE)
{
pInfo->last_rx = 0;
goto char_to_buf;
}
pInfo->last_rx = DLE;
break;
}
else if((c==ETX) && (pInfo->last_rx==DLE))
{
if(pInfo->flags & R3964_BCC)
{
pInfo->state = R3964_WAIT_FOR_BCC;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
}
else
{
on_receive_block(pInfo);
}
}
else
{
pInfo->last_rx = c;
char_to_buf:
pInfo->rx_buf[pInfo->rx_position++] = c;
mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
}
}
/* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
break;
case R3964_WAIT_FOR_BCC:
pInfo->last_rx = c;
on_receive_block(pInfo);
break;
}
}
static void receive_error(struct r3964_info *pInfo, const char flag)
{
switch (flag)
{
case TTY_NORMAL:
break;
case TTY_BREAK:
TRACE_PE("received break")
pInfo->flags |= R3964_BREAK;
break;
case TTY_PARITY:
TRACE_PE("parity error")
pInfo->flags |= R3964_PARITY;
break;
case TTY_FRAME:
TRACE_PE("frame error")
pInfo->flags |= R3964_FRAME;
break;
case TTY_OVERRUN:
TRACE_PE("frame overrun")
pInfo->flags |= R3964_OVERRUN;
break;
default:
TRACE_PE("receive_error - unknown flag %d", flag);
pInfo->flags |= R3964_UNKNOWN;
break;
}
}
static void on_timeout(unsigned long priv)
{
struct r3964_info *pInfo = (void *)priv;
switch(pInfo->state)
{
case R3964_TX_REQUEST:
TRACE_PE("TX_REQUEST - timeout");
retry_transmit(pInfo);
break;
case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
put_char(pInfo, NAK);
flush(pInfo);
retry_transmit(pInfo);
break;
case R3964_WAIT_FOR_TX_ACK:
TRACE_PE("WAIT_FOR_TX_ACK - timeout");
retry_transmit(pInfo);
break;
case R3964_WAIT_FOR_RX_BUF:
TRACE_PE("WAIT_FOR_RX_BUF - timeout");
put_char(pInfo, NAK);
flush(pInfo);
pInfo->state=R3964_IDLE;
break;
case R3964_RECEIVING:
TRACE_PE("RECEIVING - timeout after %d chars",
pInfo->rx_position);
put_char(pInfo, NAK);
flush(pInfo);
pInfo->state=R3964_IDLE;
break;
case R3964_WAIT_FOR_RX_REPEAT:
TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
pInfo->state=R3964_IDLE;
break;
case R3964_WAIT_FOR_BCC:
TRACE_PE("WAIT_FOR_BCC - timeout");
put_char(pInfo, NAK);
flush(pInfo);
pInfo->state=R3964_IDLE;
break;
}
}
static struct r3964_client_info *findClient(
struct r3964_info *pInfo, pid_t pid)
{
struct r3964_client_info *pClient;
for(pClient=pInfo->firstClient; pClient; pClient=pClient->next)
{
if(pClient->pid == pid)
{
return pClient;
}
}
return NULL;
}
static int enable_signals(struct r3964_info *pInfo, pid_t pid, int arg)
{
struct r3964_client_info *pClient;
struct r3964_client_info **ppClient;
struct r3964_message *pMsg;
if((arg & R3964_SIG_ALL)==0)
{
/* Remove client from client list */
for(ppClient=&pInfo->firstClient; *ppClient; ppClient=&(*ppClient)->next)
{
pClient = *ppClient;
if(pClient->pid == pid)
{
TRACE_PS("removing client %d from client list", pid);
*ppClient = pClient->next;
while(pClient->msg_count)
{
pMsg=remove_msg(pInfo, pClient);
if(pMsg)
{
kfree(pMsg);
TRACE_M("enable_signals - msg kfree %p",pMsg);
}
}
kfree(pClient);
TRACE_M("enable_signals - kfree %p",pClient);
return 0;
}
}
return -EINVAL;
}
else
{
pClient=findClient(pInfo, pid);
if(pClient)
{
/* update signal options */
pClient->sig_flags=arg;
}
else
{
/* add client to client list */
pClient=kmalloc(sizeof(struct r3964_client_info), GFP_KERNEL);
TRACE_M("enable_signals - kmalloc %p",pClient);
if(pClient==NULL)
return -ENOMEM;
TRACE_PS("add client %d to client list", pid);
spin_lock_init(&pClient->lock);
pClient->sig_flags=arg;
pClient->pid = pid;
pClient->next=pInfo->firstClient;
pClient->first_msg = NULL;
pClient->last_msg = NULL;
pClient->next_block_to_read = NULL;
pClient->msg_count = 0;
pInfo->firstClient=pClient;
}
}
return 0;
}
static int read_telegram(struct r3964_info *pInfo, pid_t pid, unsigned char __user *buf)
{
struct r3964_client_info *pClient;
struct r3964_block_header *block;
if(!buf)
{
return -EINVAL;
}
pClient=findClient(pInfo,pid);
if(pClient==NULL)
{
return -EINVAL;
}
block=pClient->next_block_to_read;
if(!block)
{
return 0;
}
else
{
if (copy_to_user (buf, block->data, block->length))
return -EFAULT;
remove_client_block(pInfo, pClient);
return block->length;
}
return -EINVAL;
}
static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
int error_code, struct r3964_block_header *pBlock)
{
struct r3964_message *pMsg;
unsigned long flags;
if(pClient->msg_count<R3964_MAX_MSG_COUNT-1)
{
queue_the_message:
pMsg = kmalloc(sizeof(struct r3964_message), GFP_KERNEL);
TRACE_M("add_msg - kmalloc %p",pMsg);
if(pMsg==NULL) {
return;
}
spin_lock_irqsave(&pClient->lock, flags);
pMsg->msg_id = msg_id;
pMsg->arg = arg;
pMsg->error_code = error_code;
pMsg->block = pBlock;
pMsg->next = NULL;
if(pClient->last_msg==NULL)
{
pClient->first_msg=pClient->last_msg=pMsg;
}
else
{
pClient->last_msg->next = pMsg;
pClient->last_msg=pMsg;
}
pClient->msg_count++;
if(pBlock!=NULL)
{
pBlock->locks++;
}
spin_unlock_irqrestore(&pClient->lock, flags);
}
else
{
if((pClient->last_msg->msg_id == R3964_MSG_ACK)
&& (pClient->last_msg->error_code==R3964_OVERFLOW))
{
pClient->last_msg->arg++;
TRACE_PE("add_msg - inc prev OVERFLOW-msg");
}
else
{
msg_id = R3964_MSG_ACK;
arg = 0;
error_code = R3964_OVERFLOW;
pBlock = NULL;
TRACE_PE("add_msg - queue OVERFLOW-msg");
goto queue_the_message;
}
}
/* Send SIGIO signal to client process: */
if(pClient->sig_flags & R3964_USE_SIGIO)
{
kill_proc(pClient->pid, SIGIO, 1);
}
}
static struct r3964_message *remove_msg(struct r3964_info *pInfo,
struct r3964_client_info *pClient)
{
struct r3964_message *pMsg=NULL;
unsigned long flags;
if(pClient->first_msg)
{
spin_lock_irqsave(&pClient->lock, flags);
pMsg = pClient->first_msg;
pClient->first_msg = pMsg->next;
if(pClient->first_msg==NULL)
{
pClient->last_msg = NULL;
}
pClient->msg_count--;
if(pMsg->block)
{
remove_client_block(pInfo, pClient);
pClient->next_block_to_read = pMsg->block;
}
spin_unlock_irqrestore(&pClient->lock, flags);
}
return pMsg;
}
static void remove_client_block(struct r3964_info *pInfo,
struct r3964_client_info *pClient)
{
struct r3964_block_header *block;
TRACE_PS("remove_client_block PID %d", pClient->pid);
block=pClient->next_block_to_read;
if(block)
{
block->locks--;
if(block->locks==0)
{
remove_from_rx_queue(pInfo, block);
}
}
pClient->next_block_to_read = NULL;
}
/*************************************************************
* Line discipline routines
*************************************************************/
static int r3964_open(struct tty_struct *tty)
{
struct r3964_info *pInfo;
TRACE_L("open");
TRACE_L("tty=%p, PID=%d, disc_data=%p",
tty, current->pid, tty->disc_data);
pInfo=kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
TRACE_M("r3964_open - info kmalloc %p",pInfo);
if(!pInfo)
{
printk(KERN_ERR "r3964: failed to alloc info structure\n");
return -ENOMEM;
}
pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
TRACE_M("r3964_open - rx_buf kmalloc %p",pInfo->rx_buf);
if(!pInfo->rx_buf)
{
printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
kfree(pInfo);
TRACE_M("r3964_open - info kfree %p",pInfo);
return -ENOMEM;
}
pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
TRACE_M("r3964_open - tx_buf kmalloc %p",pInfo->tx_buf);
if(!pInfo->tx_buf)
{
printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
kfree(pInfo->rx_buf);
TRACE_M("r3964_open - rx_buf kfree %p",pInfo->rx_buf);
kfree(pInfo);
TRACE_M("r3964_open - info kfree %p",pInfo);
return -ENOMEM;
}
spin_lock_init(&pInfo->lock);
pInfo->tty = tty;
init_waitqueue_head (&pInfo->read_wait);
pInfo->priority = R3964_MASTER;
pInfo->rx_first = pInfo->rx_last = NULL;
pInfo->tx_first = pInfo->tx_last = NULL;
pInfo->rx_position = 0;
pInfo->tx_position = 0;
pInfo->last_rx = 0;
pInfo->blocks_in_rx_queue = 0;
pInfo->firstClient=NULL;
pInfo->state=R3964_IDLE;
pInfo->flags = R3964_DEBUG;
pInfo->nRetry = 0;
tty->disc_data = pInfo;
tty->receive_room = 65536;
init_timer(&pInfo->tmr);
pInfo->tmr.data = (unsigned long)pInfo;
pInfo->tmr.function = on_timeout;
return 0;
}
static void r3964_close(struct tty_struct *tty)
{
struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
struct r3964_client_info *pClient, *pNext;
struct r3964_message *pMsg;
struct r3964_block_header *pHeader, *pNextHeader;
unsigned long flags;
TRACE_L("close");
/*
* Make sure that our task queue isn't activated. If it
* is, take it out of the linked list.
*/
del_timer_sync(&pInfo->tmr);
/* Remove client-structs and message queues: */
pClient=pInfo->firstClient;
while(pClient)
{
pNext=pClient->next;
while(pClient->msg_count)
{
pMsg=remove_msg(pInfo, pClient);
if(pMsg)
{
kfree(pMsg);
TRACE_M("r3964_close - msg kfree %p",pMsg);
}
}
kfree(pClient);
TRACE_M("r3964_close - client kfree %p",pClient);
pClient=pNext;
}
/* Remove jobs from tx_queue: */
spin_lock_irqsave(&pInfo->lock, flags);
pHeader=pInfo->tx_first;
pInfo->tx_first=pInfo->tx_last=NULL;
spin_unlock_irqrestore(&pInfo->lock, flags);
while(pHeader)
{
pNextHeader=pHeader->next;
kfree(pHeader);
pHeader=pNextHeader;
}
/* Free buffers: */
wake_up_interruptible(&pInfo->read_wait);
kfree(pInfo->rx_buf);
TRACE_M("r3964_close - rx_buf kfree %p",pInfo->rx_buf);
kfree(pInfo->tx_buf);
TRACE_M("r3964_close - tx_buf kfree %p",pInfo->tx_buf);
kfree(pInfo);
TRACE_M("r3964_close - info kfree %p",pInfo);
}
static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
unsigned char __user *buf, size_t nr)
{
struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
struct r3964_client_info *pClient;
struct r3964_message *pMsg;
struct r3964_client_message theMsg;
DECLARE_WAITQUEUE (wait, current);
int pid = current->pid;
int count;
TRACE_L("read()");
pClient=findClient(pInfo, pid);
if(pClient)
{
pMsg = remove_msg(pInfo, pClient);
if(pMsg==NULL)
{
/* no messages available. */
if (file->f_flags & O_NONBLOCK)
{
return -EAGAIN;
}
/* block until there is a message: */
add_wait_queue(&pInfo->read_wait, &wait);
repeat:
current->state = TASK_INTERRUPTIBLE;
pMsg = remove_msg(pInfo, pClient);
if (!pMsg && !signal_pending(current))
{
schedule();
goto repeat;
}
current->state = TASK_RUNNING;
remove_wait_queue(&pInfo->read_wait, &wait);
}
/* If we still haven't got a message, we must have been signalled */
if (!pMsg) return -EINTR;
/* deliver msg to client process: */
theMsg.msg_id = pMsg->msg_id;
theMsg.arg = pMsg->arg;
theMsg.error_code = pMsg->error_code;
count = sizeof(struct r3964_client_message);
kfree(pMsg);
TRACE_M("r3964_read - msg kfree %p",pMsg);
if (copy_to_user(buf,&theMsg, count))
return -EFAULT;
TRACE_PS("read - return %d", count);
return count;
}
return -EPERM;
}
static ssize_t r3964_write(struct tty_struct * tty, struct file * file,
const unsigned char *data, size_t count)
{
struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
struct r3964_block_header *pHeader;
struct r3964_client_info *pClient;
unsigned char *new_data;
int pid;
TRACE_L("write request, %d characters", count);
/*
* Verify the pointers
*/
if(!pInfo)
return -EIO;
/*
* Ensure that the caller does not wish to send too much.
*/
if (count > R3964_MTU)
{
if (pInfo->flags & R3964_DEBUG)
{
TRACE_L (KERN_WARNING
"r3964_write: truncating user packet "
"from %u to mtu %d", count, R3964_MTU);
}
count = R3964_MTU;
}
/*
* Allocate a buffer for the data and copy it from the buffer with header prepended
*/
new_data = kmalloc (count+sizeof(struct r3964_block_header), GFP_KERNEL);
TRACE_M("r3964_write - kmalloc %p",new_data);
if (new_data == NULL) {
if (pInfo->flags & R3964_DEBUG)
{
printk (KERN_ERR
"r3964_write: no memory\n");
}
return -ENOSPC;
}
pHeader = (struct r3964_block_header *)new_data;
pHeader->data = new_data + sizeof(struct r3964_block_header);
pHeader->length = count;
pHeader->locks = 0;
pHeader->owner = NULL;
pid=current->pid;
pClient=findClient(pInfo, pid);
if(pClient)
{
pHeader->owner = pClient;
}
memcpy(pHeader->data, data, count); /* We already verified this */
if(pInfo->flags & R3964_DEBUG)
{
dump_block(pHeader->data, count);
}
/*
* Add buffer to transmit-queue:
*/
add_tx_queue(pInfo, pHeader);
trigger_transmit(pInfo);
return 0;
}
static int r3964_ioctl(struct tty_struct * tty, struct file * file,
unsigned int cmd, unsigned long arg)
{
struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
if(pInfo==NULL)
return -EINVAL;
switch(cmd)
{
case R3964_ENABLE_SIGNALS:
return enable_signals(pInfo, current->pid, arg);
case R3964_SETPRIORITY:
if(arg<R3964_MASTER || arg>R3964_SLAVE)
return -EINVAL;
pInfo->priority = arg & 0xff;
return 0;
case R3964_USE_BCC:
if(arg)
pInfo->flags |= R3964_BCC;
else
pInfo->flags &= ~R3964_BCC;
return 0;
case R3964_READ_TELEGRAM:
return read_telegram(pInfo, current->pid, (unsigned char __user *)arg);
default:
return -ENOIOCTLCMD;
}
}
static void r3964_set_termios(struct tty_struct *tty, struct termios * old)
{
TRACE_L("set_termios");
}
/* Called without the kernel lock held - fine */
static unsigned int r3964_poll(struct tty_struct * tty, struct file * file,
struct poll_table_struct *wait)
{
struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
int pid=current->pid;
struct r3964_client_info *pClient;
struct r3964_message *pMsg=NULL;
unsigned long flags;
int result = POLLOUT;
TRACE_L("POLL");
pClient=findClient(pInfo,pid);
if(pClient)
{
poll_wait(file, &pInfo->read_wait, wait);
spin_lock_irqsave(&pInfo->lock, flags);
pMsg=pClient->first_msg;
spin_unlock_irqrestore(&pInfo->lock, flags);
if(pMsg)
result |= POLLIN | POLLRDNORM;
}
else
{
result = -EINVAL;
}
return result;
}
static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
char *fp, int count)
{
struct r3964_info *pInfo=(struct r3964_info*)tty->disc_data;
const unsigned char *p;
char *f, flags = 0;
int i;
for (i=count, p = cp, f = fp; i; i--, p++) {
if (f)
flags = *f++;
if(flags==TTY_NORMAL)
{
receive_char(pInfo, *p);
}
else
{
receive_error(pInfo, flags);
}
}
}
MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_R3964);
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