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n_r3964.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),
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;