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linux-next/drivers/tty/n_r3964.c
Linus Torvalds 55db4c64ed Revert "tty: make receive_buf() return the amout of bytes received" 
This reverts commit b1c43f82c5.

It was broken in so many ways, and results in random odd pty issues.

It re-introduced the buggy schedule_work() in flush_to_ldisc() that can
cause endless work-loops (see commit a5660b41af: "tty: fix endless
work loop when the buffer fills up").

It also used an "unsigned int" return value fo the ->receive_buf()
function, but then made multiple functions return a negative error code,
and didn't actually check for the error in the caller.

And it didn't actually work at all.  BenH bisected down odd tty behavior
to it:
  "It looks like the patch is causing some major malfunctions of the X
   server for me, possibly related to PTYs.  For example, cat'ing a
   large file in a gnome terminal hangs the kernel for -minutes- in a
   loop of what looks like flush_to_ldisc/workqueue code, (some ftrace
   data in the quoted bits further down).

   ...

   Some more data: It -looks- like what happens is that the
   flush_to_ldisc work queue entry constantly re-queues itself (because
   the PTY is full ?) and the workqueue thread will basically loop
   forver calling it without ever scheduling, thus starving the consumer
   process that could have emptied the PTY."

which is pretty much exactly the problem we fixed in a5660b41af.

Milton Miller pointed out the 'unsigned int' issue.

Reported-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Reported-by: Milton Miller <miltonm@bga.com>
Cc: Stefan Bigler <stefan.bigler@keymile.com>
Cc: Toby Gray <toby.gray@realvnc.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-04 06:33:24 +09:00

1264 lines
31 KiB
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/* r3964 linediscipline for linux
*
* -----------------------------------------------------------
* Copyright by
* Philips Automation Projects
* Kassel (Germany)
* -----------------------------------------------------------
* 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...) do {} while (0)
#endif
#ifdef DEBUG_PROTO_S
#define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_PS(fmt, arg...) do {} while (0)
#endif
#ifdef DEBUG_PROTO_E
#define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_PE(fmt, arg...) do {} while (0)
#endif
#ifdef DEBUG_LDISC
#define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_L(fmt, arg...) do {} while (0)
#endif
#ifdef DEBUG_QUEUE
#define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
#else
#define TRACE_Q(fmt, arg...) do {} while (0)
#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, struct pid *pid, int arg);
static int read_telegram(struct r3964_info *pInfo, struct pid *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 ktermios *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_ops 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;
/* FIXME: put_char should not be called from an IRQ */
tty_put_char(tty, ch);
pInfo->bcc ^= ch;
}
static void flush(struct r3964_info *pInfo)
{
struct tty_struct *tty = pInfo->tty;
if (tty == NULL || tty->ops->flush_chars == NULL)
return;
tty->ops->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;
}
room = tty_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:
/* FALLTHROUGH */
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,
struct pid *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, struct pid *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_nr(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);
}
}
put_pid(pClient->pid);
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_nr(pid));
spin_lock_init(&pClient->lock);
pClient->sig_flags = arg;
pClient->pid = get_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, struct pid *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),
error_code ? GFP_ATOMIC : 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_pid(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", pid_nr(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;
setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);
return 0;
}
static void r3964_close(struct tty_struct *tty)
{
struct r3964_info *pInfo = 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);
}
}
put_pid(pClient->pid);
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 = tty->disc_data;
struct r3964_client_info *pClient;
struct r3964_message *pMsg;
struct r3964_client_message theMsg;
int ret;
TRACE_L("read()");
tty_lock();
pClient = findClient(pInfo, task_pid(current));
if (pClient) {
pMsg = remove_msg(pInfo, pClient);
if (pMsg == NULL) {
/* no messages available. */
if (file->f_flags & O_NONBLOCK) {
ret = -EAGAIN;
goto unlock;
}
/* block until there is a message: */
wait_event_interruptible_tty(pInfo->read_wait,
(pMsg = remove_msg(pInfo, pClient)));
}
/* If we still haven't got a message, we must have been signalled */
if (!pMsg) {
ret = -EINTR;
goto unlock;
}
/* deliver msg to client process: */
theMsg.msg_id = pMsg->msg_id;
theMsg.arg = pMsg->arg;
theMsg.error_code = pMsg->error_code;
ret = sizeof(struct r3964_client_message);
kfree(pMsg);
TRACE_M("r3964_read - msg kfree %p", pMsg);
if (copy_to_user(buf, &theMsg, ret)) {
ret = -EFAULT;
goto unlock;
}
TRACE_PS("read - return %d", ret);
goto unlock;
}
ret = -EPERM;
unlock:
tty_unlock();
return ret;
}
static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
const unsigned char *data, size_t count)
{
struct r3964_info *pInfo = tty->disc_data;
struct r3964_block_header *pHeader;
struct r3964_client_info *pClient;
unsigned char *new_data;
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;
tty_lock();
pClient = findClient(pInfo, task_pid(current));
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);
tty_unlock();
return 0;
}
static int r3964_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
struct r3964_info *pInfo = tty->disc_data;
if (pInfo == NULL)
return -EINVAL;
switch (cmd) {
case R3964_ENABLE_SIGNALS:
return enable_signals(pInfo, task_pid(current), 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, task_pid(current),
(unsigned char __user *)arg);
default:
return -ENOIOCTLCMD;
}
}
static void r3964_set_termios(struct tty_struct *tty, struct ktermios *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 = tty->disc_data;
struct r3964_client_info *pClient;
struct r3964_message *pMsg = NULL;
unsigned long flags;
int result = POLLOUT;
TRACE_L("POLL");
pClient = findClient(pInfo, task_pid(current));
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 = 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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