Root/drivers/tty/n_r3964.c

1/* r3964 linediscipline for linux
2 *
3 * -----------------------------------------------------------
4 * Copyright by
5 * Philips Automation Projects
6 * Kassel (Germany)
7 * -----------------------------------------------------------
8 * This software may be used and distributed according to the terms of
9 * the GNU General Public License, incorporated herein by reference.
10 *
11 * Author:
12 * L. Haag
13 *
14 * $Log: n_r3964.c,v $
15 * Revision 1.10 2001/03/18 13:02:24 dwmw2
16 * Fix timer usage, use spinlocks properly.
17 *
18 * Revision 1.9 2001/03/18 12:52:14 dwmw2
19 * Merge changes in 2.4.2
20 *
21 * Revision 1.8 2000/03/23 14:14:54 dwmw2
22 * Fix race in sleeping in r3964_read()
23 *
24 * Revision 1.7 1999/28/08 11:41:50 dwmw2
25 * Port to 2.3 kernel
26 *
27 * Revision 1.6 1998/09/30 00:40:40 dwmw2
28 * Fixed compilation on 2.0.x kernels
29 * Updated to newly registered tty-ldisc number 9
30 *
31 * Revision 1.5 1998/09/04 21:57:36 dwmw2
32 * Signal handling bug fixes, port to 2.1.x.
33 *
34 * Revision 1.4 1998/04/02 20:26:59 lhaag
35 * select, blocking, ...
36 *
37 * Revision 1.3 1998/02/12 18:58:43 root
38 * fixed some memory leaks
39 * calculation of checksum characters
40 *
41 * Revision 1.2 1998/02/07 13:03:34 root
42 * ioctl read_telegram
43 *
44 * Revision 1.1 1998/02/06 19:21:03 root
45 * Initial revision
46 *
47 *
48 */
49
50#include <linux/module.h>
51#include <linux/kernel.h>
52#include <linux/sched.h>
53#include <linux/types.h>
54#include <linux/fcntl.h>
55#include <linux/interrupt.h>
56#include <linux/ptrace.h>
57#include <linux/ioport.h>
58#include <linux/in.h>
59#include <linux/slab.h>
60#include <linux/tty.h>
61#include <linux/errno.h>
62#include <linux/string.h> /* used in new tty drivers */
63#include <linux/signal.h> /* used in new tty drivers */
64#include <linux/ioctl.h>
65#include <linux/n_r3964.h>
66#include <linux/poll.h>
67#include <linux/init.h>
68#include <asm/uaccess.h>
69
70/*#define DEBUG_QUEUE*/
71
72/* Log successful handshake and protocol operations */
73/*#define DEBUG_PROTO_S*/
74
75/* Log handshake and protocol errors: */
76/*#define DEBUG_PROTO_E*/
77
78/* Log Linediscipline operations (open, close, read, write...): */
79/*#define DEBUG_LDISC*/
80
81/* Log module and memory operations (init, cleanup; kmalloc, kfree): */
82/*#define DEBUG_MODUL*/
83
84/* Macro helpers for debug output: */
85#define TRACE(format, args...) printk("r3964: " format "\n" , ## args)
86
87#ifdef DEBUG_MODUL
88#define TRACE_M(format, args...) printk("r3964: " format "\n" , ## args)
89#else
90#define TRACE_M(fmt, arg...) do {} while (0)
91#endif
92#ifdef DEBUG_PROTO_S
93#define TRACE_PS(format, args...) printk("r3964: " format "\n" , ## args)
94#else
95#define TRACE_PS(fmt, arg...) do {} while (0)
96#endif
97#ifdef DEBUG_PROTO_E
98#define TRACE_PE(format, args...) printk("r3964: " format "\n" , ## args)
99#else
100#define TRACE_PE(fmt, arg...) do {} while (0)
101#endif
102#ifdef DEBUG_LDISC
103#define TRACE_L(format, args...) printk("r3964: " format "\n" , ## args)
104#else
105#define TRACE_L(fmt, arg...) do {} while (0)
106#endif
107#ifdef DEBUG_QUEUE
108#define TRACE_Q(format, args...) printk("r3964: " format "\n" , ## args)
109#else
110#define TRACE_Q(fmt, arg...) do {} while (0)
111#endif
112static void add_tx_queue(struct r3964_info *, struct r3964_block_header *);
113static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code);
114static void put_char(struct r3964_info *pInfo, unsigned char ch);
115static void trigger_transmit(struct r3964_info *pInfo);
116static void retry_transmit(struct r3964_info *pInfo);
117static void transmit_block(struct r3964_info *pInfo);
118static void receive_char(struct r3964_info *pInfo, const unsigned char c);
119static void receive_error(struct r3964_info *pInfo, const char flag);
120static void on_timeout(unsigned long priv);
121static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg);
122static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
123        unsigned char __user * buf);
124static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
125        int error_code, struct r3964_block_header *pBlock);
126static struct r3964_message *remove_msg(struct r3964_info *pInfo,
127        struct r3964_client_info *pClient);
128static void remove_client_block(struct r3964_info *pInfo,
129        struct r3964_client_info *pClient);
130
131static int r3964_open(struct tty_struct *tty);
132static void r3964_close(struct tty_struct *tty);
133static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
134        unsigned char __user * buf, size_t nr);
135static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
136        const unsigned char *buf, size_t nr);
137static int r3964_ioctl(struct tty_struct *tty, struct file *file,
138        unsigned int cmd, unsigned long arg);
139static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old);
140static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
141        struct poll_table_struct *wait);
142static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
143        char *fp, int count);
144
145static struct tty_ldisc_ops tty_ldisc_N_R3964 = {
146    .owner = THIS_MODULE,
147    .magic = TTY_LDISC_MAGIC,
148    .name = "R3964",
149    .open = r3964_open,
150    .close = r3964_close,
151    .read = r3964_read,
152    .write = r3964_write,
153    .ioctl = r3964_ioctl,
154    .set_termios = r3964_set_termios,
155    .poll = r3964_poll,
156    .receive_buf = r3964_receive_buf,
157};
158
159static void dump_block(const unsigned char *block, unsigned int length)
160{
161    unsigned int i, j;
162    char linebuf[16 * 3 + 1];
163
164    for (i = 0; i < length; i += 16) {
165        for (j = 0; (j < 16) && (j + i < length); j++) {
166            sprintf(linebuf + 3 * j, "%02x ", block[i + j]);
167        }
168        linebuf[3 * j] = '\0';
169        TRACE_PS("%s", linebuf);
170    }
171}
172
173/*************************************************************
174 * Driver initialisation
175 *************************************************************/
176
177/*************************************************************
178 * Module support routines
179 *************************************************************/
180
181static void __exit r3964_exit(void)
182{
183    int status;
184
185    TRACE_M("cleanup_module()");
186
187    status = tty_unregister_ldisc(N_R3964);
188
189    if (status != 0) {
190        printk(KERN_ERR "r3964: error unregistering linediscipline: "
191                "%d\n", status);
192    } else {
193        TRACE_L("linediscipline successfully unregistered");
194    }
195}
196
197static int __init r3964_init(void)
198{
199    int status;
200
201    printk("r3964: Philips r3964 Driver $Revision: 1.10 $\n");
202
203    /*
204     * Register the tty line discipline
205     */
206
207    status = tty_register_ldisc(N_R3964, &tty_ldisc_N_R3964);
208    if (status == 0) {
209        TRACE_L("line discipline %d registered", N_R3964);
210        TRACE_L("flags=%x num=%x", tty_ldisc_N_R3964.flags,
211            tty_ldisc_N_R3964.num);
212        TRACE_L("open=%p", tty_ldisc_N_R3964.open);
213        TRACE_L("tty_ldisc_N_R3964 = %p", &tty_ldisc_N_R3964);
214    } else {
215        printk(KERN_ERR "r3964: error registering line discipline: "
216                "%d\n", status);
217    }
218    return status;
219}
220
221module_init(r3964_init);
222module_exit(r3964_exit);
223
224/*************************************************************
225 * Protocol implementation routines
226 *************************************************************/
227
228static void add_tx_queue(struct r3964_info *pInfo,
229             struct r3964_block_header *pHeader)
230{
231    unsigned long flags;
232
233    spin_lock_irqsave(&pInfo->lock, flags);
234
235    pHeader->next = NULL;
236
237    if (pInfo->tx_last == NULL) {
238        pInfo->tx_first = pInfo->tx_last = pHeader;
239    } else {
240        pInfo->tx_last->next = pHeader;
241        pInfo->tx_last = pHeader;
242    }
243
244    spin_unlock_irqrestore(&pInfo->lock, flags);
245
246    TRACE_Q("add_tx_queue %p, length %d, tx_first = %p",
247        pHeader, pHeader->length, pInfo->tx_first);
248}
249
250static void remove_from_tx_queue(struct r3964_info *pInfo, int error_code)
251{
252    struct r3964_block_header *pHeader;
253    unsigned long flags;
254#ifdef DEBUG_QUEUE
255    struct r3964_block_header *pDump;
256#endif
257
258    pHeader = pInfo->tx_first;
259
260    if (pHeader == NULL)
261        return;
262
263#ifdef DEBUG_QUEUE
264    printk("r3964: remove_from_tx_queue: %p, length %u - ",
265        pHeader, pHeader->length);
266    for (pDump = pHeader; pDump; pDump = pDump->next)
267        printk("%p ", pDump);
268    printk("\n");
269#endif
270
271    if (pHeader->owner) {
272        if (error_code) {
273            add_msg(pHeader->owner, R3964_MSG_ACK, 0,
274                error_code, NULL);
275        } else {
276            add_msg(pHeader->owner, R3964_MSG_ACK, pHeader->length,
277                error_code, NULL);
278        }
279        wake_up_interruptible(&pInfo->read_wait);
280    }
281
282    spin_lock_irqsave(&pInfo->lock, flags);
283
284    pInfo->tx_first = pHeader->next;
285    if (pInfo->tx_first == NULL) {
286        pInfo->tx_last = NULL;
287    }
288
289    spin_unlock_irqrestore(&pInfo->lock, flags);
290
291    kfree(pHeader);
292    TRACE_M("remove_from_tx_queue - kfree %p", pHeader);
293
294    TRACE_Q("remove_from_tx_queue: tx_first = %p, tx_last = %p",
295        pInfo->tx_first, pInfo->tx_last);
296}
297
298static void add_rx_queue(struct r3964_info *pInfo,
299             struct r3964_block_header *pHeader)
300{
301    unsigned long flags;
302
303    spin_lock_irqsave(&pInfo->lock, flags);
304
305    pHeader->next = NULL;
306
307    if (pInfo->rx_last == NULL) {
308        pInfo->rx_first = pInfo->rx_last = pHeader;
309    } else {
310        pInfo->rx_last->next = pHeader;
311        pInfo->rx_last = pHeader;
312    }
313    pInfo->blocks_in_rx_queue++;
314
315    spin_unlock_irqrestore(&pInfo->lock, flags);
316
317    TRACE_Q("add_rx_queue: %p, length = %d, rx_first = %p, count = %d",
318        pHeader, pHeader->length,
319        pInfo->rx_first, pInfo->blocks_in_rx_queue);
320}
321
322static void remove_from_rx_queue(struct r3964_info *pInfo,
323                 struct r3964_block_header *pHeader)
324{
325    unsigned long flags;
326    struct r3964_block_header *pFind;
327
328    if (pHeader == NULL)
329        return;
330
331    TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
332        pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
333    TRACE_Q("remove_from_rx_queue: %p, length %u",
334        pHeader, pHeader->length);
335
336    spin_lock_irqsave(&pInfo->lock, flags);
337
338    if (pInfo->rx_first == pHeader) {
339        /* Remove the first block in the linked list: */
340        pInfo->rx_first = pHeader->next;
341
342        if (pInfo->rx_first == NULL) {
343            pInfo->rx_last = NULL;
344        }
345        pInfo->blocks_in_rx_queue--;
346    } else {
347        /* Find block to remove: */
348        for (pFind = pInfo->rx_first; pFind; pFind = pFind->next) {
349            if (pFind->next == pHeader) {
350                /* Got it. */
351                pFind->next = pHeader->next;
352                pInfo->blocks_in_rx_queue--;
353                if (pFind->next == NULL) {
354                    /* Oh, removed the last one! */
355                    pInfo->rx_last = pFind;
356                }
357                break;
358            }
359        }
360    }
361
362    spin_unlock_irqrestore(&pInfo->lock, flags);
363
364    kfree(pHeader);
365    TRACE_M("remove_from_rx_queue - kfree %p", pHeader);
366
367    TRACE_Q("remove_from_rx_queue: rx_first = %p, rx_last = %p, count = %d",
368        pInfo->rx_first, pInfo->rx_last, pInfo->blocks_in_rx_queue);
369}
370
371static void put_char(struct r3964_info *pInfo, unsigned char ch)
372{
373    struct tty_struct *tty = pInfo->tty;
374    /* FIXME: put_char should not be called from an IRQ */
375    tty_put_char(tty, ch);
376    pInfo->bcc ^= ch;
377}
378
379static void flush(struct r3964_info *pInfo)
380{
381    struct tty_struct *tty = pInfo->tty;
382
383    if (tty == NULL || tty->ops->flush_chars == NULL)
384        return;
385    tty->ops->flush_chars(tty);
386}
387
388static void trigger_transmit(struct r3964_info *pInfo)
389{
390    unsigned long flags;
391
392    spin_lock_irqsave(&pInfo->lock, flags);
393
394    if ((pInfo->state == R3964_IDLE) && (pInfo->tx_first != NULL)) {
395        pInfo->state = R3964_TX_REQUEST;
396        pInfo->nRetry = 0;
397        pInfo->flags &= ~R3964_ERROR;
398        mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
399
400        spin_unlock_irqrestore(&pInfo->lock, flags);
401
402        TRACE_PS("trigger_transmit - sent STX");
403
404        put_char(pInfo, STX);
405        flush(pInfo);
406
407        pInfo->bcc = 0;
408    } else {
409        spin_unlock_irqrestore(&pInfo->lock, flags);
410    }
411}
412
413static void retry_transmit(struct r3964_info *pInfo)
414{
415    if (pInfo->nRetry < R3964_MAX_RETRIES) {
416        TRACE_PE("transmission failed. Retry #%d", pInfo->nRetry);
417        pInfo->bcc = 0;
418        put_char(pInfo, STX);
419        flush(pInfo);
420        pInfo->state = R3964_TX_REQUEST;
421        pInfo->nRetry++;
422        mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
423    } else {
424        TRACE_PE("transmission failed after %d retries",
425             R3964_MAX_RETRIES);
426
427        remove_from_tx_queue(pInfo, R3964_TX_FAIL);
428
429        put_char(pInfo, NAK);
430        flush(pInfo);
431        pInfo->state = R3964_IDLE;
432
433        trigger_transmit(pInfo);
434    }
435}
436
437static void transmit_block(struct r3964_info *pInfo)
438{
439    struct tty_struct *tty = pInfo->tty;
440    struct r3964_block_header *pBlock = pInfo->tx_first;
441    int room = 0;
442
443    if (tty == NULL || pBlock == NULL) {
444        return;
445    }
446
447    room = tty_write_room(tty);
448
449    TRACE_PS("transmit_block %p, room %d, length %d",
450         pBlock, room, pBlock->length);
451
452    while (pInfo->tx_position < pBlock->length) {
453        if (room < 2)
454            break;
455
456        if (pBlock->data[pInfo->tx_position] == DLE) {
457            /* send additional DLE char: */
458            put_char(pInfo, DLE);
459        }
460        put_char(pInfo, pBlock->data[pInfo->tx_position++]);
461
462        room--;
463    }
464
465    if ((pInfo->tx_position == pBlock->length) && (room >= 3)) {
466        put_char(pInfo, DLE);
467        put_char(pInfo, ETX);
468        if (pInfo->flags & R3964_BCC) {
469            put_char(pInfo, pInfo->bcc);
470        }
471        pInfo->state = R3964_WAIT_FOR_TX_ACK;
472        mod_timer(&pInfo->tmr, jiffies + R3964_TO_QVZ);
473    }
474    flush(pInfo);
475}
476
477static void on_receive_block(struct r3964_info *pInfo)
478{
479    unsigned int length;
480    struct r3964_client_info *pClient;
481    struct r3964_block_header *pBlock;
482
483    length = pInfo->rx_position;
484
485    /* compare byte checksum characters: */
486    if (pInfo->flags & R3964_BCC) {
487        if (pInfo->bcc != pInfo->last_rx) {
488            TRACE_PE("checksum error - got %x but expected %x",
489                 pInfo->last_rx, pInfo->bcc);
490            pInfo->flags |= R3964_CHECKSUM;
491        }
492    }
493
494    /* check for errors (parity, overrun,...): */
495    if (pInfo->flags & R3964_ERROR) {
496        TRACE_PE("on_receive_block - transmission failed error %x",
497             pInfo->flags & R3964_ERROR);
498
499        put_char(pInfo, NAK);
500        flush(pInfo);
501        if (pInfo->nRetry < R3964_MAX_RETRIES) {
502            pInfo->state = R3964_WAIT_FOR_RX_REPEAT;
503            pInfo->nRetry++;
504            mod_timer(&pInfo->tmr, jiffies + R3964_TO_RX_PANIC);
505        } else {
506            TRACE_PE("on_receive_block - failed after max retries");
507            pInfo->state = R3964_IDLE;
508        }
509        return;
510    }
511
512    /* received block; submit DLE: */
513    put_char(pInfo, DLE);
514    flush(pInfo);
515    del_timer_sync(&pInfo->tmr);
516    TRACE_PS(" rx success: got %d chars", length);
517
518    /* prepare struct r3964_block_header: */
519    pBlock = kmalloc(length + sizeof(struct r3964_block_header),
520            GFP_KERNEL);
521    TRACE_M("on_receive_block - kmalloc %p", pBlock);
522
523    if (pBlock == NULL)
524        return;
525
526    pBlock->length = length;
527    pBlock->data = ((unsigned char *)pBlock) +
528            sizeof(struct r3964_block_header);
529    pBlock->locks = 0;
530    pBlock->next = NULL;
531    pBlock->owner = NULL;
532
533    memcpy(pBlock->data, pInfo->rx_buf, length);
534
535    /* queue block into rx_queue: */
536    add_rx_queue(pInfo, pBlock);
537
538    /* notify attached client processes: */
539    for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
540        if (pClient->sig_flags & R3964_SIG_DATA) {
541            add_msg(pClient, R3964_MSG_DATA, length, R3964_OK,
542                pBlock);
543        }
544    }
545    wake_up_interruptible(&pInfo->read_wait);
546
547    pInfo->state = R3964_IDLE;
548
549    trigger_transmit(pInfo);
550}
551
552static void receive_char(struct r3964_info *pInfo, const unsigned char c)
553{
554    switch (pInfo->state) {
555    case R3964_TX_REQUEST:
556        if (c == DLE) {
557            TRACE_PS("TX_REQUEST - got DLE");
558
559            pInfo->state = R3964_TRANSMITTING;
560            pInfo->tx_position = 0;
561
562            transmit_block(pInfo);
563        } else if (c == STX) {
564            if (pInfo->nRetry == 0) {
565                TRACE_PE("TX_REQUEST - init conflict");
566                if (pInfo->priority == R3964_SLAVE) {
567                    goto start_receiving;
568                }
569            } else {
570                TRACE_PE("TX_REQUEST - secondary init "
571                    "conflict!? Switching to SLAVE mode "
572                    "for next rx.");
573                goto start_receiving;
574            }
575        } else {
576            TRACE_PE("TX_REQUEST - char != DLE: %x", c);
577            retry_transmit(pInfo);
578        }
579        break;
580    case R3964_TRANSMITTING:
581        if (c == NAK) {
582            TRACE_PE("TRANSMITTING - got NAK");
583            retry_transmit(pInfo);
584        } else {
585            TRACE_PE("TRANSMITTING - got invalid char");
586
587            pInfo->state = R3964_WAIT_ZVZ_BEFORE_TX_RETRY;
588            mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
589        }
590        break;
591    case R3964_WAIT_FOR_TX_ACK:
592        if (c == DLE) {
593            TRACE_PS("WAIT_FOR_TX_ACK - got DLE");
594            remove_from_tx_queue(pInfo, R3964_OK);
595
596            pInfo->state = R3964_IDLE;
597            trigger_transmit(pInfo);
598        } else {
599            retry_transmit(pInfo);
600        }
601        break;
602    case R3964_WAIT_FOR_RX_REPEAT:
603        /* FALLTHROUGH */
604    case R3964_IDLE:
605        if (c == STX) {
606            /* Prevent rx_queue from overflow: */
607            if (pInfo->blocks_in_rx_queue >=
608                R3964_MAX_BLOCKS_IN_RX_QUEUE) {
609                TRACE_PE("IDLE - got STX but no space in "
610                        "rx_queue!");
611                pInfo->state = R3964_WAIT_FOR_RX_BUF;
612                mod_timer(&pInfo->tmr,
613                      jiffies + R3964_TO_NO_BUF);
614                break;
615            }
616start_receiving:
617            /* Ok, start receiving: */
618            TRACE_PS("IDLE - got STX");
619            pInfo->rx_position = 0;
620            pInfo->last_rx = 0;
621            pInfo->flags &= ~R3964_ERROR;
622            pInfo->state = R3964_RECEIVING;
623            mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
624            pInfo->nRetry = 0;
625            put_char(pInfo, DLE);
626            flush(pInfo);
627            pInfo->bcc = 0;
628        }
629        break;
630    case R3964_RECEIVING:
631        if (pInfo->rx_position < RX_BUF_SIZE) {
632            pInfo->bcc ^= c;
633
634            if (c == DLE) {
635                if (pInfo->last_rx == DLE) {
636                    pInfo->last_rx = 0;
637                    goto char_to_buf;
638                }
639                pInfo->last_rx = DLE;
640                break;
641            } else if ((c == ETX) && (pInfo->last_rx == DLE)) {
642                if (pInfo->flags & R3964_BCC) {
643                    pInfo->state = R3964_WAIT_FOR_BCC;
644                    mod_timer(&pInfo->tmr,
645                          jiffies + R3964_TO_ZVZ);
646                } else {
647                    on_receive_block(pInfo);
648                }
649            } else {
650                pInfo->last_rx = c;
651char_to_buf:
652                pInfo->rx_buf[pInfo->rx_position++] = c;
653                mod_timer(&pInfo->tmr, jiffies + R3964_TO_ZVZ);
654            }
655        }
656        /* else: overflow-msg? BUF_SIZE>MTU; should not happen? */
657        break;
658    case R3964_WAIT_FOR_BCC:
659        pInfo->last_rx = c;
660        on_receive_block(pInfo);
661        break;
662    }
663}
664
665static void receive_error(struct r3964_info *pInfo, const char flag)
666{
667    switch (flag) {
668    case TTY_NORMAL:
669        break;
670    case TTY_BREAK:
671        TRACE_PE("received break");
672        pInfo->flags |= R3964_BREAK;
673        break;
674    case TTY_PARITY:
675        TRACE_PE("parity error");
676        pInfo->flags |= R3964_PARITY;
677        break;
678    case TTY_FRAME:
679        TRACE_PE("frame error");
680        pInfo->flags |= R3964_FRAME;
681        break;
682    case TTY_OVERRUN:
683        TRACE_PE("frame overrun");
684        pInfo->flags |= R3964_OVERRUN;
685        break;
686    default:
687        TRACE_PE("receive_error - unknown flag %d", flag);
688        pInfo->flags |= R3964_UNKNOWN;
689        break;
690    }
691}
692
693static void on_timeout(unsigned long priv)
694{
695    struct r3964_info *pInfo = (void *)priv;
696
697    switch (pInfo->state) {
698    case R3964_TX_REQUEST:
699        TRACE_PE("TX_REQUEST - timeout");
700        retry_transmit(pInfo);
701        break;
702    case R3964_WAIT_ZVZ_BEFORE_TX_RETRY:
703        put_char(pInfo, NAK);
704        flush(pInfo);
705        retry_transmit(pInfo);
706        break;
707    case R3964_WAIT_FOR_TX_ACK:
708        TRACE_PE("WAIT_FOR_TX_ACK - timeout");
709        retry_transmit(pInfo);
710        break;
711    case R3964_WAIT_FOR_RX_BUF:
712        TRACE_PE("WAIT_FOR_RX_BUF - timeout");
713        put_char(pInfo, NAK);
714        flush(pInfo);
715        pInfo->state = R3964_IDLE;
716        break;
717    case R3964_RECEIVING:
718        TRACE_PE("RECEIVING - timeout after %d chars",
719             pInfo->rx_position);
720        put_char(pInfo, NAK);
721        flush(pInfo);
722        pInfo->state = R3964_IDLE;
723        break;
724    case R3964_WAIT_FOR_RX_REPEAT:
725        TRACE_PE("WAIT_FOR_RX_REPEAT - timeout");
726        pInfo->state = R3964_IDLE;
727        break;
728    case R3964_WAIT_FOR_BCC:
729        TRACE_PE("WAIT_FOR_BCC - timeout");
730        put_char(pInfo, NAK);
731        flush(pInfo);
732        pInfo->state = R3964_IDLE;
733        break;
734    }
735}
736
737static struct r3964_client_info *findClient(struct r3964_info *pInfo,
738        struct pid *pid)
739{
740    struct r3964_client_info *pClient;
741
742    for (pClient = pInfo->firstClient; pClient; pClient = pClient->next) {
743        if (pClient->pid == pid) {
744            return pClient;
745        }
746    }
747    return NULL;
748}
749
750static int enable_signals(struct r3964_info *pInfo, struct pid *pid, int arg)
751{
752    struct r3964_client_info *pClient;
753    struct r3964_client_info **ppClient;
754    struct r3964_message *pMsg;
755
756    if ((arg & R3964_SIG_ALL) == 0) {
757        /* Remove client from client list */
758        for (ppClient = &pInfo->firstClient; *ppClient;
759             ppClient = &(*ppClient)->next) {
760            pClient = *ppClient;
761
762            if (pClient->pid == pid) {
763                TRACE_PS("removing client %d from client list",
764                     pid_nr(pid));
765                *ppClient = pClient->next;
766                while (pClient->msg_count) {
767                    pMsg = remove_msg(pInfo, pClient);
768                    if (pMsg) {
769                        kfree(pMsg);
770                        TRACE_M("enable_signals - msg "
771                            "kfree %p", pMsg);
772                    }
773                }
774                put_pid(pClient->pid);
775                kfree(pClient);
776                TRACE_M("enable_signals - kfree %p", pClient);
777                return 0;
778            }
779        }
780        return -EINVAL;
781    } else {
782        pClient = findClient(pInfo, pid);
783        if (pClient) {
784            /* update signal options */
785            pClient->sig_flags = arg;
786        } else {
787            /* add client to client list */
788            pClient = kmalloc(sizeof(struct r3964_client_info),
789                    GFP_KERNEL);
790            TRACE_M("enable_signals - kmalloc %p", pClient);
791            if (pClient == NULL)
792                return -ENOMEM;
793
794            TRACE_PS("add client %d to client list", pid_nr(pid));
795            spin_lock_init(&pClient->lock);
796            pClient->sig_flags = arg;
797            pClient->pid = get_pid(pid);
798            pClient->next = pInfo->firstClient;
799            pClient->first_msg = NULL;
800            pClient->last_msg = NULL;
801            pClient->next_block_to_read = NULL;
802            pClient->msg_count = 0;
803            pInfo->firstClient = pClient;
804        }
805    }
806
807    return 0;
808}
809
810static int read_telegram(struct r3964_info *pInfo, struct pid *pid,
811             unsigned char __user * buf)
812{
813    struct r3964_client_info *pClient;
814    struct r3964_block_header *block;
815
816    if (!buf) {
817        return -EINVAL;
818    }
819
820    pClient = findClient(pInfo, pid);
821    if (pClient == NULL) {
822        return -EINVAL;
823    }
824
825    block = pClient->next_block_to_read;
826    if (!block) {
827        return 0;
828    } else {
829        if (copy_to_user(buf, block->data, block->length))
830            return -EFAULT;
831
832        remove_client_block(pInfo, pClient);
833        return block->length;
834    }
835
836    return -EINVAL;
837}
838
839static void add_msg(struct r3964_client_info *pClient, int msg_id, int arg,
840        int error_code, struct r3964_block_header *pBlock)
841{
842    struct r3964_message *pMsg;
843    unsigned long flags;
844
845    if (pClient->msg_count < R3964_MAX_MSG_COUNT - 1) {
846queue_the_message:
847
848        pMsg = kmalloc(sizeof(struct r3964_message),
849                error_code ? GFP_ATOMIC : GFP_KERNEL);
850        TRACE_M("add_msg - kmalloc %p", pMsg);
851        if (pMsg == NULL) {
852            return;
853        }
854
855        spin_lock_irqsave(&pClient->lock, flags);
856
857        pMsg->msg_id = msg_id;
858        pMsg->arg = arg;
859        pMsg->error_code = error_code;
860        pMsg->block = pBlock;
861        pMsg->next = NULL;
862
863        if (pClient->last_msg == NULL) {
864            pClient->first_msg = pClient->last_msg = pMsg;
865        } else {
866            pClient->last_msg->next = pMsg;
867            pClient->last_msg = pMsg;
868        }
869
870        pClient->msg_count++;
871
872        if (pBlock != NULL) {
873            pBlock->locks++;
874        }
875        spin_unlock_irqrestore(&pClient->lock, flags);
876    } else {
877        if ((pClient->last_msg->msg_id == R3964_MSG_ACK)
878            && (pClient->last_msg->error_code == R3964_OVERFLOW)) {
879            pClient->last_msg->arg++;
880            TRACE_PE("add_msg - inc prev OVERFLOW-msg");
881        } else {
882            msg_id = R3964_MSG_ACK;
883            arg = 0;
884            error_code = R3964_OVERFLOW;
885            pBlock = NULL;
886            TRACE_PE("add_msg - queue OVERFLOW-msg");
887            goto queue_the_message;
888        }
889    }
890    /* Send SIGIO signal to client process: */
891    if (pClient->sig_flags & R3964_USE_SIGIO) {
892        kill_pid(pClient->pid, SIGIO, 1);
893    }
894}
895
896static struct r3964_message *remove_msg(struct r3964_info *pInfo,
897                    struct r3964_client_info *pClient)
898{
899    struct r3964_message *pMsg = NULL;
900    unsigned long flags;
901
902    if (pClient->first_msg) {
903        spin_lock_irqsave(&pClient->lock, flags);
904
905        pMsg = pClient->first_msg;
906        pClient->first_msg = pMsg->next;
907        if (pClient->first_msg == NULL) {
908            pClient->last_msg = NULL;
909        }
910
911        pClient->msg_count--;
912        if (pMsg->block) {
913            remove_client_block(pInfo, pClient);
914            pClient->next_block_to_read = pMsg->block;
915        }
916        spin_unlock_irqrestore(&pClient->lock, flags);
917    }
918    return pMsg;
919}
920
921static void remove_client_block(struct r3964_info *pInfo,
922                struct r3964_client_info *pClient)
923{
924    struct r3964_block_header *block;
925
926    TRACE_PS("remove_client_block PID %d", pid_nr(pClient->pid));
927
928    block = pClient->next_block_to_read;
929    if (block) {
930        block->locks--;
931        if (block->locks == 0) {
932            remove_from_rx_queue(pInfo, block);
933        }
934    }
935    pClient->next_block_to_read = NULL;
936}
937
938/*************************************************************
939 * Line discipline routines
940 *************************************************************/
941
942static int r3964_open(struct tty_struct *tty)
943{
944    struct r3964_info *pInfo;
945
946    TRACE_L("open");
947    TRACE_L("tty=%p, PID=%d, disc_data=%p",
948        tty, current->pid, tty->disc_data);
949
950    pInfo = kmalloc(sizeof(struct r3964_info), GFP_KERNEL);
951    TRACE_M("r3964_open - info kmalloc %p", pInfo);
952
953    if (!pInfo) {
954        printk(KERN_ERR "r3964: failed to alloc info structure\n");
955        return -ENOMEM;
956    }
957
958    pInfo->rx_buf = kmalloc(RX_BUF_SIZE, GFP_KERNEL);
959    TRACE_M("r3964_open - rx_buf kmalloc %p", pInfo->rx_buf);
960
961    if (!pInfo->rx_buf) {
962        printk(KERN_ERR "r3964: failed to alloc receive buffer\n");
963        kfree(pInfo);
964        TRACE_M("r3964_open - info kfree %p", pInfo);
965        return -ENOMEM;
966    }
967
968    pInfo->tx_buf = kmalloc(TX_BUF_SIZE, GFP_KERNEL);
969    TRACE_M("r3964_open - tx_buf kmalloc %p", pInfo->tx_buf);
970
971    if (!pInfo->tx_buf) {
972        printk(KERN_ERR "r3964: failed to alloc transmit buffer\n");
973        kfree(pInfo->rx_buf);
974        TRACE_M("r3964_open - rx_buf kfree %p", pInfo->rx_buf);
975        kfree(pInfo);
976        TRACE_M("r3964_open - info kfree %p", pInfo);
977        return -ENOMEM;
978    }
979
980    spin_lock_init(&pInfo->lock);
981    pInfo->tty = tty;
982    init_waitqueue_head(&pInfo->read_wait);
983    pInfo->priority = R3964_MASTER;
984    pInfo->rx_first = pInfo->rx_last = NULL;
985    pInfo->tx_first = pInfo->tx_last = NULL;
986    pInfo->rx_position = 0;
987    pInfo->tx_position = 0;
988    pInfo->last_rx = 0;
989    pInfo->blocks_in_rx_queue = 0;
990    pInfo->firstClient = NULL;
991    pInfo->state = R3964_IDLE;
992    pInfo->flags = R3964_DEBUG;
993    pInfo->nRetry = 0;
994
995    tty->disc_data = pInfo;
996    tty->receive_room = 65536;
997
998    setup_timer(&pInfo->tmr, on_timeout, (unsigned long)pInfo);
999
1000    return 0;
1001}
1002
1003static void r3964_close(struct tty_struct *tty)
1004{
1005    struct r3964_info *pInfo = tty->disc_data;
1006    struct r3964_client_info *pClient, *pNext;
1007    struct r3964_message *pMsg;
1008    struct r3964_block_header *pHeader, *pNextHeader;
1009    unsigned long flags;
1010
1011    TRACE_L("close");
1012
1013    /*
1014     * Make sure that our task queue isn't activated. If it
1015     * is, take it out of the linked list.
1016     */
1017    del_timer_sync(&pInfo->tmr);
1018
1019    /* Remove client-structs and message queues: */
1020    pClient = pInfo->firstClient;
1021    while (pClient) {
1022        pNext = pClient->next;
1023        while (pClient->msg_count) {
1024            pMsg = remove_msg(pInfo, pClient);
1025            if (pMsg) {
1026                kfree(pMsg);
1027                TRACE_M("r3964_close - msg kfree %p", pMsg);
1028            }
1029        }
1030        put_pid(pClient->pid);
1031        kfree(pClient);
1032        TRACE_M("r3964_close - client kfree %p", pClient);
1033        pClient = pNext;
1034    }
1035    /* Remove jobs from tx_queue: */
1036    spin_lock_irqsave(&pInfo->lock, flags);
1037    pHeader = pInfo->tx_first;
1038    pInfo->tx_first = pInfo->tx_last = NULL;
1039    spin_unlock_irqrestore(&pInfo->lock, flags);
1040
1041    while (pHeader) {
1042        pNextHeader = pHeader->next;
1043        kfree(pHeader);
1044        pHeader = pNextHeader;
1045    }
1046
1047    /* Free buffers: */
1048    wake_up_interruptible(&pInfo->read_wait);
1049    kfree(pInfo->rx_buf);
1050    TRACE_M("r3964_close - rx_buf kfree %p", pInfo->rx_buf);
1051    kfree(pInfo->tx_buf);
1052    TRACE_M("r3964_close - tx_buf kfree %p", pInfo->tx_buf);
1053    kfree(pInfo);
1054    TRACE_M("r3964_close - info kfree %p", pInfo);
1055}
1056
1057static ssize_t r3964_read(struct tty_struct *tty, struct file *file,
1058              unsigned char __user * buf, size_t nr)
1059{
1060    struct r3964_info *pInfo = tty->disc_data;
1061    struct r3964_client_info *pClient;
1062    struct r3964_message *pMsg;
1063    struct r3964_client_message theMsg;
1064    int ret;
1065
1066    TRACE_L("read()");
1067
1068    tty_lock();
1069
1070    pClient = findClient(pInfo, task_pid(current));
1071    if (pClient) {
1072        pMsg = remove_msg(pInfo, pClient);
1073        if (pMsg == NULL) {
1074            /* no messages available. */
1075            if (file->f_flags & O_NONBLOCK) {
1076                ret = -EAGAIN;
1077                goto unlock;
1078            }
1079            /* block until there is a message: */
1080            wait_event_interruptible_tty(pInfo->read_wait,
1081                    (pMsg = remove_msg(pInfo, pClient)));
1082        }
1083
1084        /* If we still haven't got a message, we must have been signalled */
1085
1086        if (!pMsg) {
1087            ret = -EINTR;
1088            goto unlock;
1089        }
1090
1091        /* deliver msg to client process: */
1092        theMsg.msg_id = pMsg->msg_id;
1093        theMsg.arg = pMsg->arg;
1094        theMsg.error_code = pMsg->error_code;
1095        ret = sizeof(struct r3964_client_message);
1096
1097        kfree(pMsg);
1098        TRACE_M("r3964_read - msg kfree %p", pMsg);
1099
1100        if (copy_to_user(buf, &theMsg, ret)) {
1101            ret = -EFAULT;
1102            goto unlock;
1103        }
1104
1105        TRACE_PS("read - return %d", ret);
1106        goto unlock;
1107    }
1108    ret = -EPERM;
1109unlock:
1110    tty_unlock();
1111    return ret;
1112}
1113
1114static ssize_t r3964_write(struct tty_struct *tty, struct file *file,
1115               const unsigned char *data, size_t count)
1116{
1117    struct r3964_info *pInfo = tty->disc_data;
1118    struct r3964_block_header *pHeader;
1119    struct r3964_client_info *pClient;
1120    unsigned char *new_data;
1121
1122    TRACE_L("write request, %d characters", count);
1123/*
1124 * Verify the pointers
1125 */
1126
1127    if (!pInfo)
1128        return -EIO;
1129
1130/*
1131 * Ensure that the caller does not wish to send too much.
1132 */
1133    if (count > R3964_MTU) {
1134        if (pInfo->flags & R3964_DEBUG) {
1135            TRACE_L(KERN_WARNING "r3964_write: truncating user "
1136                "packet from %u to mtu %d", count, R3964_MTU);
1137        }
1138        count = R3964_MTU;
1139    }
1140/*
1141 * Allocate a buffer for the data and copy it from the buffer with header prepended
1142 */
1143    new_data = kmalloc(count + sizeof(struct r3964_block_header),
1144            GFP_KERNEL);
1145    TRACE_M("r3964_write - kmalloc %p", new_data);
1146    if (new_data == NULL) {
1147        if (pInfo->flags & R3964_DEBUG) {
1148            printk(KERN_ERR "r3964_write: no memory\n");
1149        }
1150        return -ENOSPC;
1151    }
1152
1153    pHeader = (struct r3964_block_header *)new_data;
1154    pHeader->data = new_data + sizeof(struct r3964_block_header);
1155    pHeader->length = count;
1156    pHeader->locks = 0;
1157    pHeader->owner = NULL;
1158
1159    tty_lock();
1160
1161    pClient = findClient(pInfo, task_pid(current));
1162    if (pClient) {
1163        pHeader->owner = pClient;
1164    }
1165
1166    memcpy(pHeader->data, data, count); /* We already verified this */
1167
1168    if (pInfo->flags & R3964_DEBUG) {
1169        dump_block(pHeader->data, count);
1170    }
1171
1172/*
1173 * Add buffer to transmit-queue:
1174 */
1175    add_tx_queue(pInfo, pHeader);
1176    trigger_transmit(pInfo);
1177
1178    tty_unlock();
1179
1180    return 0;
1181}
1182
1183static int r3964_ioctl(struct tty_struct *tty, struct file *file,
1184        unsigned int cmd, unsigned long arg)
1185{
1186    struct r3964_info *pInfo = tty->disc_data;
1187    if (pInfo == NULL)
1188        return -EINVAL;
1189    switch (cmd) {
1190    case R3964_ENABLE_SIGNALS:
1191        return enable_signals(pInfo, task_pid(current), arg);
1192    case R3964_SETPRIORITY:
1193        if (arg < R3964_MASTER || arg > R3964_SLAVE)
1194            return -EINVAL;
1195        pInfo->priority = arg & 0xff;
1196        return 0;
1197    case R3964_USE_BCC:
1198        if (arg)
1199            pInfo->flags |= R3964_BCC;
1200        else
1201            pInfo->flags &= ~R3964_BCC;
1202        return 0;
1203    case R3964_READ_TELEGRAM:
1204        return read_telegram(pInfo, task_pid(current),
1205                (unsigned char __user *)arg);
1206    default:
1207        return -ENOIOCTLCMD;
1208    }
1209}
1210
1211static void r3964_set_termios(struct tty_struct *tty, struct ktermios *old)
1212{
1213    TRACE_L("set_termios");
1214}
1215
1216/* Called without the kernel lock held - fine */
1217static unsigned int r3964_poll(struct tty_struct *tty, struct file *file,
1218            struct poll_table_struct *wait)
1219{
1220    struct r3964_info *pInfo = tty->disc_data;
1221    struct r3964_client_info *pClient;
1222    struct r3964_message *pMsg = NULL;
1223    unsigned long flags;
1224    int result = POLLOUT;
1225
1226    TRACE_L("POLL");
1227
1228    pClient = findClient(pInfo, task_pid(current));
1229    if (pClient) {
1230        poll_wait(file, &pInfo->read_wait, wait);
1231        spin_lock_irqsave(&pInfo->lock, flags);
1232        pMsg = pClient->first_msg;
1233        spin_unlock_irqrestore(&pInfo->lock, flags);
1234        if (pMsg)
1235            result |= POLLIN | POLLRDNORM;
1236    } else {
1237        result = -EINVAL;
1238    }
1239    return result;
1240}
1241
1242static void r3964_receive_buf(struct tty_struct *tty, const unsigned char *cp,
1243            char *fp, int count)
1244{
1245    struct r3964_info *pInfo = tty->disc_data;
1246    const unsigned char *p;
1247    char *f, flags = 0;
1248    int i;
1249
1250    for (i = count, p = cp, f = fp; i; i--, p++) {
1251        if (f)
1252            flags = *f++;
1253        if (flags == TTY_NORMAL) {
1254            receive_char(pInfo, *p);
1255        } else {
1256            receive_error(pInfo, flags);
1257        }
1258
1259    }
1260}
1261
1262MODULE_LICENSE("GPL");
1263MODULE_ALIAS_LDISC(N_R3964);
1264

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