Commit ed5aecd3 authored by Jiri Slaby's avatar Jiri Slaby Committed by Greg Kroah-Hartman

tty: remove broken r3964 line discipline

Noone stepped up in the past two years since it was marked as BROKEN by
commit c7084edc (tty: mark Siemens R3964 line discipline as BROKEN).
Remove the line discipline for good.

Three remarks:
* we remove also the uapi header (as noone is able to use that interface
  anyway)
* we do *not* remove the N_R3964 constant definition from tty.h, so it
  remains reserved.
* in_interrupt() check is now removed from vt's con_put_char. Noone else
  calls tty_operations::put_char from interrupt context.
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210505091928.22010-2-jslaby@suse.czSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d7e325aa
...@@ -621,7 +621,6 @@ CONFIG_HW_RANDOM=y ...@@ -621,7 +621,6 @@ CONFIG_HW_RANDOM=y
CONFIG_HW_RANDOM_VIRTIO=m CONFIG_HW_RANDOM_VIRTIO=m
CONFIG_NVRAM=y CONFIG_NVRAM=y
CONFIG_DTLK=m CONFIG_DTLK=m
CONFIG_R3964=m
CONFIG_CARDMAN_4000=m CONFIG_CARDMAN_4000=m
CONFIG_CARDMAN_4040=m CONFIG_CARDMAN_4040=m
CONFIG_IPWIRELESS=m CONFIG_IPWIRELESS=m
......
...@@ -218,19 +218,6 @@ config XILINX_HWICAP ...@@ -218,19 +218,6 @@ config XILINX_HWICAP
If unsure, say N. If unsure, say N.
config R3964
tristate "Siemens R3964 line discipline"
depends on TTY && BROKEN
help
This driver allows synchronous communication with devices using the
Siemens R3964 packet protocol. Unless you are dealing with special
hardware like PLCs, you are unlikely to need this.
To compile this driver as a module, choose M here: the
module will be called n_r3964.
If unsure, say N.
config APPLICOM config APPLICOM
tristate "Applicom intelligent fieldbus card support" tristate "Applicom intelligent fieldbus card support"
depends on PCI depends on PCI
......
...@@ -9,7 +9,6 @@ obj-$(CONFIG_AUDIT) += tty_audit.o ...@@ -9,7 +9,6 @@ obj-$(CONFIG_AUDIT) += tty_audit.o
obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o obj-$(CONFIG_MAGIC_SYSRQ) += sysrq.o
obj-$(CONFIG_N_HDLC) += n_hdlc.o obj-$(CONFIG_N_HDLC) += n_hdlc.o
obj-$(CONFIG_N_GSM) += n_gsm.o obj-$(CONFIG_N_GSM) += n_gsm.o
obj-$(CONFIG_R3964) += n_r3964.o
obj-y += vt/ obj-y += vt/
obj-$(CONFIG_HVC_DRIVER) += hvc/ obj-$(CONFIG_HVC_DRIVER) += hvc/
......
// SPDX-License-Identifier: GPL-1.0+
/* r3964 linediscipline for linux
*
* -----------------------------------------------------------
* Copyright by
* Philips Automation Projects
* Kassel (Germany)
* -----------------------------------------------------------
* 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 <linux/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(struct timer_list *t);
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,
void *cookie, unsigned char *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);
#ifdef CONFIG_COMPAT
static int r3964_compat_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg);
#endif
static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
static __poll_t 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,
.name = "R3964",
.open = r3964_open,
.close = r3964_close,
.read = r3964_read,
.write = r3964_write,
.ioctl = r3964_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = r3964_compat_ioctl,
#endif
.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->tty->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->tty->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:
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(struct timer_list *t)
{
struct r3964_info *pInfo = from_timer(pInfo, t, tmr);
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);
mutex_init(&pInfo->read_lock);
pInfo->tty = tty;
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;
timer_setup(&pInfo->tmr, on_timeout, 0);
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: */
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 *kbuf, size_t nr,
void **cookie, unsigned long offset)
{
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()");
/*
* Internal serialization of reads.
*/
if (file->f_flags & O_NONBLOCK) {
if (!mutex_trylock(&pInfo->read_lock))
return -EAGAIN;
} else {
if (mutex_lock_interruptible(&pInfo->read_lock))
return -ERESTARTSYS;
}
pClient = findClient(pInfo, task_pid(current));
if (pClient) {
pMsg = remove_msg(pInfo, pClient);
if (pMsg == NULL) {
/* no messages available. */
if (tty_io_nonblock(tty, file)) {
ret = -EAGAIN;
goto unlock;
}
/* block until there is a message: */
wait_event_interruptible(tty->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);
memcpy(kbuf, &theMsg, ret);
TRACE_PS("read - return %d", ret);
goto unlock;
}
ret = -EPERM;
unlock:
mutex_unlock(&pInfo->read_lock);
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;
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);
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;
}
}
#ifdef CONFIG_COMPAT
static int r3964_compat_ioctl(struct tty_struct *tty, struct file *file,
unsigned int cmd, unsigned long arg)
{
switch (cmd) {
case R3964_ENABLE_SIGNALS:
case R3964_SETPRIORITY:
case R3964_USE_BCC:
return r3964_ioctl(tty, file, cmd, arg);
default:
return -ENOIOCTLCMD;
}
}
#endif
static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
{
TRACE_L("set_termios");
}
/* Called without the kernel lock held - fine */
static __poll_t 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;
__poll_t result = EPOLLOUT;
TRACE_L("POLL");
pClient = findClient(pInfo, task_pid(current));
if (pClient) {
poll_wait(file, &tty->read_wait, wait);
spin_lock_irqsave(&pInfo->lock, flags);
pMsg = pClient->first_msg;
spin_unlock_irqrestore(&pInfo->lock, flags);
if (pMsg)
result |= EPOLLIN | EPOLLRDNORM;
} 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 = TTY_NORMAL;
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);
...@@ -3260,8 +3260,6 @@ static int con_write(struct tty_struct *tty, const unsigned char *buf, int count ...@@ -3260,8 +3260,6 @@ static int con_write(struct tty_struct *tty, const unsigned char *buf, int count
static int con_put_char(struct tty_struct *tty, unsigned char ch) static int con_put_char(struct tty_struct *tty, unsigned char ch)
{ {
if (in_interrupt())
return 0; /* n_r3964 calls put_char() from interrupt context */
return do_con_write(tty, &ch, 1); return do_con_write(tty, &ch, 1);
} }
......
/* 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: r3964.h,v $
* Revision 1.4 2005/12/21 19:54:24 Kurt Huwig <kurt huwig de>
* Fixed HZ usage on 2.6 kernels
* Removed unnecessary include
*
* Revision 1.3 2001/03/18 13:02:24 dwmw2
* Fix timer usage, use spinlocks properly.
*
* Revision 1.2 2001/03/18 12:53:15 dwmw2
* Merge changes in 2.4.2
*
* Revision 1.1.1.1 1998/10/13 16:43:14 dwmw2
* This'll screw the version control
*
* Revision 1.6 1998/09/30 00:40:38 dwmw2
* Updated to use kernel's N_R3964 if available
*
* Revision 1.4 1998/04/02 20:29:44 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 13:03:17 root
* ioctl read_telegram
*
* Revision 1.1 1998/02/06 19:19:43 root
* Initial revision
*
*
*/
#ifndef __LINUX_N_R3964_H__
#define __LINUX_N_R3964_H__
#include <linux/param.h>
#include <uapi/linux/n_r3964.h>
/*
* Common ascii handshake characters:
*/
#define STX 0x02
#define ETX 0x03
#define DLE 0x10
#define NAK 0x15
/*
* Timeouts (from milliseconds to jiffies)
*/
#define R3964_TO_QVZ ((550)*HZ/1000)
#define R3964_TO_ZVZ ((220)*HZ/1000)
#define R3964_TO_NO_BUF ((400)*HZ/1000)
#define R3964_NO_TX_ROOM ((100)*HZ/1000)
#define R3964_TO_RX_PANIC ((4000)*HZ/1000)
#define R3964_MAX_RETRIES 5
enum { R3964_IDLE,
R3964_TX_REQUEST, R3964_TRANSMITTING,
R3964_WAIT_ZVZ_BEFORE_TX_RETRY, R3964_WAIT_FOR_TX_ACK,
R3964_WAIT_FOR_RX_BUF,
R3964_RECEIVING, R3964_WAIT_FOR_BCC, R3964_WAIT_FOR_RX_REPEAT
};
/*
* All open file-handles are 'clients' and are stored in a linked list:
*/
struct r3964_message;
struct r3964_client_info {
spinlock_t lock;
struct pid *pid;
unsigned int sig_flags;
struct r3964_client_info *next;
struct r3964_message *first_msg;
struct r3964_message *last_msg;
struct r3964_block_header *next_block_to_read;
int msg_count;
};
struct r3964_block_header;
/* internal version of client_message: */
struct r3964_message {
int msg_id;
int arg;
int error_code;
struct r3964_block_header *block;
struct r3964_message *next;
};
/*
* Header of received block in rx_buf/tx_buf:
*/
struct r3964_block_header
{
unsigned int length; /* length in chars without header */
unsigned char *data; /* usually data is located
immediately behind this struct */
unsigned int locks; /* only used in rx_buffer */
struct r3964_block_header *next;
struct r3964_client_info *owner; /* =NULL in rx_buffer */
};
/*
* If rx_buf hasn't enough space to store R3964_MTU chars,
* we will reject all incoming STX-requests by sending NAK.
*/
#define RX_BUF_SIZE 4000
#define TX_BUF_SIZE 4000
#define R3964_MAX_BLOCKS_IN_RX_QUEUE 100
#define R3964_PARITY 0x0001
#define R3964_FRAME 0x0002
#define R3964_OVERRUN 0x0004
#define R3964_UNKNOWN 0x0008
#define R3964_BREAK 0x0010
#define R3964_CHECKSUM 0x0020
#define R3964_ERROR 0x003f
#define R3964_BCC 0x4000
#define R3964_DEBUG 0x8000
struct r3964_info {
spinlock_t lock;
struct tty_struct *tty;
unsigned char priority;
unsigned char *rx_buf; /* ring buffer */
unsigned char *tx_buf;
struct r3964_block_header *rx_first;
struct r3964_block_header *rx_last;
struct r3964_block_header *tx_first;
struct r3964_block_header *tx_last;
unsigned int tx_position;
unsigned int rx_position;
unsigned char last_rx;
unsigned char bcc;
unsigned int blocks_in_rx_queue;
struct mutex read_lock; /* serialize r3964_read */
struct r3964_client_info *firstClient;
unsigned int state;
unsigned int flags;
struct timer_list tmr;
int nRetry;
};
#endif
/* SPDX-License-Identifier: GPL-1.0+ WITH Linux-syscall-note */
/* 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: r3964.h,v $
* Revision 1.4 2005/12/21 19:54:24 Kurt Huwig <kurt huwig de>
* Fixed HZ usage on 2.6 kernels
* Removed unnecessary include
*
* Revision 1.3 2001/03/18 13:02:24 dwmw2
* Fix timer usage, use spinlocks properly.
*
* Revision 1.2 2001/03/18 12:53:15 dwmw2
* Merge changes in 2.4.2
*
* Revision 1.1.1.1 1998/10/13 16:43:14 dwmw2
* This'll screw the version control
*
* Revision 1.6 1998/09/30 00:40:38 dwmw2
* Updated to use kernel's N_R3964 if available
*
* Revision 1.4 1998/04/02 20:29:44 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 13:03:17 root
* ioctl read_telegram
*
* Revision 1.1 1998/02/06 19:19:43 root
* Initial revision
*
*
*/
#ifndef _UAPI__LINUX_N_R3964_H__
#define _UAPI__LINUX_N_R3964_H__
/* line disciplines for r3964 protocol */
/*
* Ioctl-commands
*/
#define R3964_ENABLE_SIGNALS 0x5301
#define R3964_SETPRIORITY 0x5302
#define R3964_USE_BCC 0x5303
#define R3964_READ_TELEGRAM 0x5304
/* Options for R3964_SETPRIORITY */
#define R3964_MASTER 0
#define R3964_SLAVE 1
/* Options for R3964_ENABLE_SIGNALS */
#define R3964_SIG_ACK 0x0001
#define R3964_SIG_DATA 0x0002
#define R3964_SIG_ALL 0x000f
#define R3964_SIG_NONE 0x0000
#define R3964_USE_SIGIO 0x1000
/*
* r3964 operation states:
*/
/* types for msg_id: */
enum {R3964_MSG_ACK=1, R3964_MSG_DATA };
#define R3964_MAX_MSG_COUNT 32
/* error codes for client messages */
#define R3964_OK 0 /* no error. */
#define R3964_TX_FAIL -1 /* transmission error, block NOT sent */
#define R3964_OVERFLOW -2 /* msg queue overflow */
/* the client gets this struct when calling read(fd,...): */
struct r3964_client_message {
int msg_id;
int arg;
int error_code;
};
#define R3964_MTU 256
#endif /* _UAPI__LINUX_N_R3964_H__ */
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