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 void trigger_transmit(struct r3964_info *pInfo)
{
unsigned long flags;
save_flags(flags);
cli();
if((pInfo->state == R3964_IDLE) && (pInfo->tx_first!=NULL))
{
pInfo->state = R3964_TX_REQUEST;
pInfo->count_down = R3964_TO_QVZ;
pInfo->nRetry=0;
pInfo->flags &= ~R3964_ERROR;
restore_flags(flags);
TRACE_PS("trigger_transmit - sent STX");
put_char(pInfo, STX);
flush(pInfo);
pInfo->bcc = 0;
}
else
{
restore_flags(flags);
}
}
static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
unsigned char *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 %x",(int)pMsg);
if (copy_to_user(buf,&theMsg, count))
return -EFAULT;
TRACE_PS("read - return %d", count);
return count;
}
return -EPERM;
}
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 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 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);
}
}
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;
}
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 %x, room %d, length %d",
(int)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;
pInfo->count_down = R3964_TO_QVZ;
}
flush(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) {
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 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 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);
}
