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c96cf923a9
There might be situations where tty_ldisc_lock() has blocked, but there is already IO on tty and it prevents line discipline changes. It might theoretically turn into dead-lock. Basically, provide more priority to pending tty_ldisc_lock() than to servicing reads/writes over tty. User-visible issue was reported by Mikulas where on pa-risc with Debian 5 reboot took either 80 seconds, 3 minutes or 3:25 after proper locking in tty_reopen(). Cc: Jiri Slaby <jslaby@suse.com> Reported-by: Mikulas Patocka <mpatocka@redhat.com> Signed-off-by: Dmitry Safonov <dima@arista.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
1288 lines
31 KiB
C
1288 lines
31 KiB
C
// SPDX-License-Identifier: GPL-1.0+
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/* r3964 linediscipline for linux
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*
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* -----------------------------------------------------------
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* Copyright by
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* Philips Automation Projects
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* Kassel (Germany)
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* -----------------------------------------------------------
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* Author:
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* L. Haag
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*
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* $Log: n_r3964.c,v $
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* Revision 1.10 2001/03/18 13:02:24 dwmw2
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* Fix timer usage, use spinlocks properly.
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*
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* Revision 1.9 2001/03/18 12:52:14 dwmw2
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* Merge changes in 2.4.2
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*
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* Revision 1.8 2000/03/23 14:14:54 dwmw2
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* Fix race in sleeping in r3964_read()
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*
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* Revision 1.7 1999/28/08 11:41:50 dwmw2
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* Port to 2.3 kernel
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*
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* Revision 1.6 1998/09/30 00:40:40 dwmw2
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* Fixed compilation on 2.0.x kernels
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* Updated to newly registered tty-ldisc number 9
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*
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* Revision 1.5 1998/09/04 21:57:36 dwmw2
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* Signal handling bug fixes, port to 2.1.x.
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*
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* Revision 1.4 1998/04/02 20:26:59 lhaag
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* select, blocking, ...
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*
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* Revision 1.3 1998/02/12 18:58:43 root
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* fixed some memory leaks
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* calculation of checksum characters
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*
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* Revision 1.2 1998/02/07 13:03:34 root
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* ioctl read_telegram
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*
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* Revision 1.1 1998/02/06 19:21:03 root
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* Initial revision
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*
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/types.h>
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#include <linux/fcntl.h>
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#include <linux/interrupt.h>
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#include <linux/ptrace.h>
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#include <linux/ioport.h>
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#include <linux/in.h>
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#include <linux/slab.h>
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#include <linux/tty.h>
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#include <linux/errno.h>
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#include <linux/string.h> /* used in new tty drivers */
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#include <linux/signal.h> /* used in new tty drivers */
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#include <linux/ioctl.h>
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#include <linux/n_r3964.h>
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#include <linux/poll.h>
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#include <linux/init.h>
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#include <linux/uaccess.h>
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/*#define DEBUG_QUEUE*/
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/* Log successful handshake and protocol operations */
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/*#define DEBUG_PROTO_S*/
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/* Log handshake and protocol errors: */
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/*#define DEBUG_PROTO_E*/
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/* Log Linediscipline operations (open, close, read, write...): */
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/*#define DEBUG_LDISC*/
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/* Log module and memory operations (init, cleanup; kmalloc, kfree): */
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/*#define DEBUG_MODUL*/
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/* Macro helpers for debug output: */
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#define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
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#ifdef DEBUG_MODUL
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#define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
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#else
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#define TRACE_M(fmt, arg...) do {} while (0)
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#endif
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#ifdef DEBUG_PROTO_S
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#define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
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#else
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#define TRACE_PS(fmt, arg...) do {} while (0)
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#endif
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#ifdef DEBUG_PROTO_E
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#define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
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#else
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#define TRACE_PE(fmt, arg...) do {} while (0)
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#endif
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#ifdef DEBUG_LDISC
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#define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
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#else
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#define TRACE_L(fmt, arg...) do {} while (0)
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#endif
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#ifdef DEBUG_QUEUE
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#define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
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#else
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#define TRACE_Q(fmt, arg...) do {} while (0)
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#endif
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static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
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static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
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static void put_char(struct r3964_info *pInfo, unsigned char ch);
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static void trigger_transmit(struct r3964_info *pInfo);
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static void retry_transmit(struct r3964_info *pInfo);
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static void transmit_block(struct r3964_info *pInfo);
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static void receive_char(struct r3964_info *pInfo, const unsigned char c);
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static void receive_error(struct r3964_info *pInfo, const char flag);
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static void on_timeout(struct timer_list *t);
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static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
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static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
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unsigned char __user * buf);
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static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
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int error_code, struct r3964_block_header *pBlock);
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static struct r3964_message *remove_msg(struct r3964_info *pInfo,
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struct r3964_client_info *pClient);
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static void remove_client_block(struct r3964_info *pInfo,
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struct r3964_client_info *pClient);
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static int r3964_open(struct tty_struct *tty);
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static void r3964_close(struct tty_struct *tty);
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static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
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unsigned char __user * buf, size_t nr);
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static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
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const unsigned char *buf, size_t nr);
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static int r3964_ioctl(struct tty_struct *tty, struct file *file,
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unsigned int cmd, unsigned long arg);
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#ifdef CONFIG_COMPAT
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static int r3964_compat_ioctl(struct tty_struct *tty, struct file *file,
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unsigned int cmd, unsigned long arg);
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#endif
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static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
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static __poll_t r3964_poll(struct tty_struct *tty, struct file *file,
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struct poll_table_struct *wait);
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static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
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char *fp, int count);
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static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
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.owner = THIS_MODULE,
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.magic = TTY_LDISC_MAGIC,
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.name = "R3964",
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.open = r3964_open,
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.close = r3964_close,
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.read = r3964_read,
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.write = r3964_write,
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.ioctl = r3964_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = r3964_compat_ioctl,
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#endif
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.set_termios = r3964_set_termios,
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.poll = r3964_poll,
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.receive_buf = r3964_receive_buf,
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};
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static void dump_block(const unsigned char *block, unsigned int length)
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{
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unsigned int i, j;
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char linebuf[16 * 3 + 1];
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for (i = 0; i < length; i += 16) {
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for (j = 0; (j < 16) && (j + i < length); j++) {
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sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
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}
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linebuf[3 * j] = '\0';
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TRACE_PS("%s", linebuf);
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}
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}
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/*************************************************************
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* Driver initialisation
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*************************************************************/
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/*************************************************************
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* Module support routines
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*************************************************************/
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static void __exit r3964_exit(void)
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{
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int status;
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TRACE_M("cleanup_module()");
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status = tty_unregister_ldisc(N_R3964);
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if (status != 0) {
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printk(KERN_ERR "r3964: error unregistering linediscipline: "
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"%d\n", status);
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} else {
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TRACE_L("linediscipline successfully unregistered");
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}
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}
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static int __init r3964_init(void)
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{
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int status;
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printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
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/*
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* Register the tty line discipline
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*/
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status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
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if (status == 0) {
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TRACE_L("line discipline %d registered", N_R3964);
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TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
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tty_ldisc_N_R3964.num);
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TRACE_L("open=%p", tty_ldisc_N_R3964.open);
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TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
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} else {
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printk(KERN_ERR "r3964: error registering line discipline: "
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"%d\n", status);
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}
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return status;
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}
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module_init(r3964_init);
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module_exit(r3964_exit);
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/*************************************************************
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* Protocol implementation routines
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*************************************************************/
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static void add_tx_queue(struct r3964_info *pInfo,
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struct r3964_block_header *pHeader)
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{
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unsigned long flags;
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spin_lock_irqsave(&pInfo->lock, flags);
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pHeader->next = NULL;
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if (pInfo->tx_last == NULL) {
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pInfo->tx_first = pInfo->tx_last = pHeader;
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} else {
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pInfo->tx_last->next = pHeader;
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pInfo->tx_last = pHeader;
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}
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spin_unlock_irqrestore(&pInfo->lock, flags);
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TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
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pHeader, pHeader->length, pInfo->tx_first);
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}
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static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
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{
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struct r3964_block_header *pHeader;
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unsigned long flags;
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#ifdef DEBUG_QUEUE
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struct r3964_block_header *pDump;
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#endif
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pHeader = pInfo->tx_first;
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if (pHeader == NULL)
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return;
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#ifdef DEBUG_QUEUE
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printk("r3964: remove_from_tx_queue: %p, length %u - ",
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pHeader, pHeader->length);
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for (pDump = pHeader; pDump; pDump = pDump->next)
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printk("%p ", pDump);
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printk("\n");
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#endif
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if (pHeader->owner) {
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if (error_code) {
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add_msg(pHeader->owner, R3964_MSG_ACK, 0,
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error_code, NULL);
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} else {
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add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
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error_code, NULL);
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}
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wake_up_interruptible(&pInfo->tty->read_wait);
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}
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spin_lock_irqsave(&pInfo->lock, flags);
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pInfo->tx_first = pHeader->next;
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if (pInfo->tx_first == NULL) {
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pInfo->tx_last = NULL;
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}
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spin_unlock_irqrestore(&pInfo->lock, flags);
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kfree(pHeader);
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TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
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TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
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pInfo->tx_first, pInfo->tx_last);
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}
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static void add_rx_queue(struct r3964_info *pInfo,
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struct r3964_block_header *pHeader)
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{
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unsigned long flags;
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spin_lock_irqsave(&pInfo->lock, flags);
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pHeader->next = NULL;
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if (pInfo->rx_last == NULL) {
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pInfo->rx_first = pInfo->rx_last = pHeader;
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} else {
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pInfo->rx_last->next = pHeader;
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pInfo->rx_last = pHeader;
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}
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pInfo->blocks_in_rx_queue++;
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spin_unlock_irqrestore(&pInfo->lock, flags);
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TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
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pHeader, pHeader->length,
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pInfo->rx_first, pInfo->blocks_in_rx_queue);
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}
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static void remove_from_rx_queue(struct r3964_info *pInfo,
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struct r3964_block_header *pHeader)
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{
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unsigned long flags;
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struct r3964_block_header *pFind;
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if (pHeader == NULL)
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return;
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TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
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pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
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TRACE_Q("remove_from_rx_queue: %p, length %u",
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pHeader, pHeader->length);
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spin_lock_irqsave(&pInfo->lock, flags);
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if (pInfo->rx_first == pHeader) {
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/* Remove the first block in the linked list: */
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pInfo->rx_first = pHeader->next;
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if (pInfo->rx_first == NULL) {
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pInfo->rx_last = NULL;
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}
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pInfo->blocks_in_rx_queue--;
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} else {
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/* Find block to remove: */
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for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
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if (pFind->next == pHeader) {
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/* Got it. */
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pFind->next = pHeader->next;
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pInfo->blocks_in_rx_queue--;
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if (pFind->next == NULL) {
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/* Oh, removed the last one! */
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pInfo->rx_last = pFind;
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}
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break;
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}
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}
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}
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spin_unlock_irqrestore(&pInfo->lock, flags);
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kfree(pHeader);
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TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
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TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
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pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
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}
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static void put_char(struct r3964_info *pInfo, unsigned char ch)
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{
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struct tty_struct *tty = pInfo->tty;
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/* FIXME: put_char should not be called from an IRQ */
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tty_put_char(tty, ch);
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pInfo->bcc ^= ch;
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}
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static void flush(struct r3964_info *pInfo)
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{
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struct tty_struct *tty = pInfo->tty;
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if (tty == NULL || tty->ops->flush_chars == NULL)
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return;
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tty->ops->flush_chars(tty);
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}
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static void trigger_transmit(struct r3964_info *pInfo)
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{
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unsigned long flags;
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spin_lock_irqsave(&pInfo->lock, flags);
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if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
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pInfo->state = R3964_TX_REQUEST;
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pInfo->nRetry = 0;
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pInfo->flags &= ~R3964_ERROR;
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mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
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spin_unlock_irqrestore(&pInfo->lock, flags);
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TRACE_PS("trigger_transmit - sent STX");
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put_char(pInfo, STX);
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flush(pInfo);
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pInfo->bcc = 0;
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} else {
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spin_unlock_irqrestore(&pInfo->lock, flags);
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}
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}
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static void retry_transmit(struct r3964_info *pInfo)
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{
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if (pInfo->nRetry < R3964_MAX_RETRIES) {
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TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
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pInfo->bcc = 0;
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put_char(pInfo, STX);
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flush(pInfo);
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pInfo->state = R3964_TX_REQUEST;
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pInfo->nRetry++;
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mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
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} else {
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TRACE_PE("transmission failed after %d retries",
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R3964_MAX_RETRIES);
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remove_from_tx_queue(pInfo, R3964_TX_FAIL);
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put_char(pInfo, NAK);
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flush(pInfo);
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pInfo->state = R3964_IDLE;
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trigger_transmit(pInfo);
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}
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}
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static void transmit_block(struct r3964_info *pInfo)
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{
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struct tty_struct *tty = pInfo->tty;
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struct r3964_block_header *pBlock = pInfo->tx_first;
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int room = 0;
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if (tty == NULL || pBlock == NULL) {
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return;
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}
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room = tty_write_room(tty);
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TRACE_PS("transmit_block %p, room %d, length %d",
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pBlock, room, pBlock->length);
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while (pInfo->tx_position < pBlock->length) {
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if (room < 2)
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break;
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if (pBlock->data[pInfo->tx_position] == DLE) {
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/* send additional DLE char: */
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put_char(pInfo, DLE);
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}
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put_char(pInfo, pBlock->data[pInfo->tx_position++]);
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room--;
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}
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if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
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put_char(pInfo, DLE);
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put_char(pInfo, ETX);
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if (pInfo->flags & R3964_BCC) {
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put_char(pInfo, pInfo->bcc);
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}
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pInfo->state = R3964_WAIT_FOR_TX_ACK;
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mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
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}
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flush(pInfo);
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}
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static void on_receive_block(struct r3964_info *pInfo)
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|
{
|
|
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:
|
|
/* FALLTHROUGH */
|
|
case R3964_IDLE:
|
|
if (c == STX) {
|
|
/* Prevent rx_queue from overflow: */
|
|
if (pInfo->blocks_in_rx_queue >=
|
|
R3964_MAX_BLOCKS_IN_RX_QUEUE) {
|
|
TRACE_PE("IDLE - got STX but no space in "
|
|
"rx_queue!");
|
|
pInfo->state = R3964_WAIT_FOR_RX_BUF;
|
|
mod_timer(&pInfo->tmr,
|
|
jiffies + R3964_TO_NO_BUF);
|
|
break;
|
|
}
|
|
start_receiving:
|
|
/* Ok, start receiving: */
|
|
TRACE_PS("IDLE - got STX");
|
|
pInfo->rx_position = 0;
|
|
pInfo->last_rx = 0;
|
|
pInfo->flags &= ~R3964_ERROR;
|
|
pInfo->state = R3964_RECEIVING;
|
|
mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
|
|
pInfo->nRetry = 0;
|
|
put_char(pInfo, DLE);
|
|
flush(pInfo);
|
|
pInfo->bcc = 0;
|
|
}
|
|
break;
|
|
case R3964_RECEIVING:
|
|
if (pInfo->rx_position < RX_BUF_SIZE) {
|
|
pInfo->bcc ^= c;
|
|
|
|
if (c == DLE) {
|
|
if (pInfo->last_rx == DLE) {
|
|
pInfo->last_rx = 0;
|
|
goto char_to_buf;
|
|
}
|
|
pInfo->last_rx = DLE;
|
|
break;
|
|
} else if ((c == ETX) && (pInfo->last_rx == DLE)) {
|
|
if (pInfo->flags & R3964_BCC) {
|
|
pInfo->state = R3964_WAIT_FOR_BCC;
|
|
mod_timer(&pInfo->tmr,
|
|
jiffies + R3964_TO_ZVZ);
|
|
} else {
|
|
on_receive_block(pInfo);
|
|
}
|
|
} else {
|
|
pInfo->last_rx = c;
|
|
char_to_buf:
|
|
pInfo->rx_buf[pInfo->rx_position++] = c;
|
|
mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
|
|
}
|
|
}
|
|
/* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
|
|
break;
|
|
case R3964_WAIT_FOR_BCC:
|
|
pInfo->last_rx = c;
|
|
on_receive_block(pInfo);
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void receive_error(struct r3964_info *pInfo, const char flag)
|
|
{
|
|
switch (flag) {
|
|
case TTY_NORMAL:
|
|
break;
|
|
case TTY_BREAK:
|
|
TRACE_PE("received break");
|
|
pInfo->flags |= R3964_BREAK;
|
|
break;
|
|
case TTY_PARITY:
|
|
TRACE_PE("parity error");
|
|
pInfo->flags |= R3964_PARITY;
|
|
break;
|
|
case TTY_FRAME:
|
|
TRACE_PE("frame error");
|
|
pInfo->flags |= R3964_FRAME;
|
|
break;
|
|
case TTY_OVERRUN:
|
|
TRACE_PE("frame overrun");
|
|
pInfo->flags |= R3964_OVERRUN;
|
|
break;
|
|
default:
|
|
TRACE_PE("receive_error - unknown flag %d", flag);
|
|
pInfo->flags |= R3964_UNKNOWN;
|
|
break;
|
|
}
|
|
}
|
|
|
|
static void on_timeout(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 __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()");
|
|
|
|
/*
|
|
* 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);
|
|
|
|
if (copy_to_user(buf, &theMsg, ret)) {
|
|
ret = -EFAULT;
|
|
goto unlock;
|
|
}
|
|
|
|
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);
|