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linux/drivers/char/n_r3964.c
Alan Cox 04f378b198 tty: BKL pushdown 
- Push the BKL down into the line disciplines
- Switch the tty layer to unlocked_ioctl
- Introduce a new ctrl_lock spin lock for the control bits
- Eliminate much of the lock_kernel use in n_tty
- Prepare to (but don't yet) call the drivers with the lock dropped
  on the paths that historically held the lock

BKL now primarily protects open/close/ldisc change in the tty layer

[jirislaby@gmail.com: a couple of fixes]
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-04-30 08:29:40 -07:00

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31 KiB
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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...) 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 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,
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 = (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);
}
}
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 = (struct r3964_info *)tty->disc_data;
struct r3964_client_info *pClient;
struct r3964_message *pMsg;
struct r3964_client_message theMsg;
int count;
TRACE_L("read()");
lock_kernel();
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) {
unlock_kernel();
return -EAGAIN;
}
/* block until there is a message: */
wait_event_interruptible(pInfo->read_wait,
(pMsg = remove_msg(pInfo, pClient)));
}
/* If we still haven't got a message, we must have been signalled */
if (!pMsg) {
unlock_kernel();
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)) {
unlock_kernel();
return -EFAULT;
}
TRACE_PS("read - return %d", count);
return count;
}
unlock_kernel();
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;
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;
lock_kernel();
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);
unlock_kernel();
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, 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 = (struct r3964_info *)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 = (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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