xref: /qemu/hw/net/can/can_sja1000.c (revision 78b54858)
1 /*
2  * CAN device - SJA1000 chip emulation for QEMU
3  *
4  * Copyright (c) 2013-2014 Jin Yang
5  * Copyright (c) 2014-2018 Pavel Pisa
6  *
7  * Initial development supported by Google GSoC 2013 from RTEMS project slot
8  *
9  * Permission is hereby granted, free of charge, to any person obtaining a copy
10  * of this software and associated documentation files (the "Software"), to deal
11  * in the Software without restriction, including without limitation the rights
12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13  * copies of the Software, and to permit persons to whom the Software is
14  * furnished to do so, subject to the following conditions:
15  *
16  * The above copyright notice and this permission notice shall be included in
17  * all copies or substantial portions of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25  * THE SOFTWARE.
26  */
27 
28 #include "qemu/osdep.h"
29 #include "qemu/log.h"
30 #include "chardev/char.h"
31 #include "hw/irq.h"
32 #include "migration/vmstate.h"
33 #include "net/can_emu.h"
34 
35 #include "can_sja1000.h"
36 
37 #ifndef DEBUG_FILTER
38 #define DEBUG_FILTER 0
39 #endif /*DEBUG_FILTER*/
40 
41 #ifndef DEBUG_CAN
42 #define DEBUG_CAN 0
43 #endif /*DEBUG_CAN*/
44 
45 #define DPRINTF(fmt, ...) \
46     do { \
47         if (DEBUG_CAN) { \
48             qemu_log("[cansja]: " fmt , ## __VA_ARGS__); \
49         } \
50     } while (0)
51 
52 static void can_sja_software_reset(CanSJA1000State *s)
53 {
54     s->mode        &= ~0x31;
55     s->mode        |= 0x01;
56     s->status_pel  &= ~0x37;
57     s->status_pel  |= 0x34;
58 
59     s->rxbuf_start = 0x00;
60     s->rxmsg_cnt   = 0x00;
61     s->rx_cnt      = 0x00;
62 }
63 
64 void can_sja_hardware_reset(CanSJA1000State *s)
65 {
66     /* Reset by hardware, p10 */
67     s->mode        = 0x01;
68     s->status_pel  = 0x3c;
69     s->interrupt_pel = 0x00;
70     s->clock       = 0x00;
71     s->rxbuf_start = 0x00;
72     s->rxmsg_cnt   = 0x00;
73     s->rx_cnt      = 0x00;
74 
75     s->control     = 0x01;
76     s->status_bas  = 0x0c;
77     s->interrupt_bas = 0x00;
78 
79     qemu_irq_lower(s->irq);
80 }
81 
82 static
83 void can_sja_single_filter(struct qemu_can_filter *filter,
84             const uint8_t *acr,  const uint8_t *amr, int extended)
85 {
86     if (extended) {
87         filter->can_id = (uint32_t)acr[0] << 21;
88         filter->can_id |= (uint32_t)acr[1] << 13;
89         filter->can_id |= (uint32_t)acr[2] << 5;
90         filter->can_id |= (uint32_t)acr[3] >> 3;
91         if (acr[3] & 4) {
92             filter->can_id |= QEMU_CAN_RTR_FLAG;
93         }
94 
95         filter->can_mask = (uint32_t)amr[0] << 21;
96         filter->can_mask |= (uint32_t)amr[1] << 13;
97         filter->can_mask |= (uint32_t)amr[2] << 5;
98         filter->can_mask |= (uint32_t)amr[3] >> 3;
99         filter->can_mask = ~filter->can_mask & QEMU_CAN_EFF_MASK;
100         if (!(amr[3] & 4)) {
101             filter->can_mask |= QEMU_CAN_RTR_FLAG;
102         }
103     } else {
104         filter->can_id = (uint32_t)acr[0] << 3;
105         filter->can_id |= (uint32_t)acr[1] >> 5;
106         if (acr[1] & 0x10) {
107             filter->can_id |= QEMU_CAN_RTR_FLAG;
108         }
109 
110         filter->can_mask = (uint32_t)amr[0] << 3;
111         filter->can_mask |= (uint32_t)amr[1] << 5;
112         filter->can_mask = ~filter->can_mask & QEMU_CAN_SFF_MASK;
113         if (!(amr[1] & 0x10)) {
114             filter->can_mask |= QEMU_CAN_RTR_FLAG;
115         }
116     }
117 }
118 
119 static
120 void can_sja_dual_filter(struct qemu_can_filter *filter,
121             const uint8_t *acr,  const uint8_t *amr, int extended)
122 {
123     if (extended) {
124         filter->can_id = (uint32_t)acr[0] << 21;
125         filter->can_id |= (uint32_t)acr[1] << 13;
126 
127         filter->can_mask = (uint32_t)amr[0] << 21;
128         filter->can_mask |= (uint32_t)amr[1] << 13;
129         filter->can_mask = ~filter->can_mask & QEMU_CAN_EFF_MASK & ~0x1fff;
130     } else {
131         filter->can_id = (uint32_t)acr[0] << 3;
132         filter->can_id |= (uint32_t)acr[1] >> 5;
133         if (acr[1] & 0x10) {
134             filter->can_id |= QEMU_CAN_RTR_FLAG;
135         }
136 
137         filter->can_mask = (uint32_t)amr[0] << 3;
138         filter->can_mask |= (uint32_t)amr[1] >> 5;
139         filter->can_mask = ~filter->can_mask & QEMU_CAN_SFF_MASK;
140         if (!(amr[1] & 0x10)) {
141             filter->can_mask |= QEMU_CAN_RTR_FLAG;
142         }
143     }
144 }
145 
146 /* Details in DS-p22, what we need to do here is to test the data. */
147 static
148 int can_sja_accept_filter(CanSJA1000State *s,
149                                  const qemu_can_frame *frame)
150 {
151 
152     struct qemu_can_filter filter;
153 
154     if (s->clock & 0x80) { /* PeliCAN Mode */
155         if (s->mode & (1 << 3)) { /* Single mode. */
156             if (frame->can_id & QEMU_CAN_EFF_FLAG) { /* EFF */
157                 can_sja_single_filter(&filter,
158                     s->code_mask + 0, s->code_mask + 4, 1);
159 
160                 if (!can_bus_filter_match(&filter, frame->can_id)) {
161                     return 0;
162                 }
163             } else { /* SFF */
164                 can_sja_single_filter(&filter,
165                     s->code_mask + 0, s->code_mask + 4, 0);
166 
167                 if (!can_bus_filter_match(&filter, frame->can_id)) {
168                     return 0;
169                 }
170 
171                 if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
172                     return 1;
173                 }
174 
175                 if (frame->can_dlc == 0) {
176                     return 1;
177                 }
178 
179                 if ((frame->data[0] & ~(s->code_mask[6])) !=
180                    (s->code_mask[2] & ~(s->code_mask[6]))) {
181                     return 0;
182                 }
183 
184                 if (frame->can_dlc < 2) {
185                     return 1;
186                 }
187 
188                 if ((frame->data[1] & ~(s->code_mask[7])) ==
189                     (s->code_mask[3] & ~(s->code_mask[7]))) {
190                     return 1;
191                 }
192 
193                 return 0;
194             }
195         } else { /* Dual mode */
196             if (frame->can_id & QEMU_CAN_EFF_FLAG) { /* EFF */
197                 can_sja_dual_filter(&filter,
198                     s->code_mask + 0, s->code_mask + 4, 1);
199 
200                 if (can_bus_filter_match(&filter, frame->can_id)) {
201                     return 1;
202                 }
203 
204                 can_sja_dual_filter(&filter,
205                     s->code_mask + 2, s->code_mask + 6, 1);
206 
207                 if (can_bus_filter_match(&filter, frame->can_id)) {
208                     return 1;
209                 }
210 
211                 return 0;
212             } else {
213                 can_sja_dual_filter(&filter,
214                     s->code_mask + 0, s->code_mask + 4, 0);
215 
216                 if (can_bus_filter_match(&filter, frame->can_id)) {
217                     uint8_t expect;
218                     uint8_t mask;
219                     expect = s->code_mask[1] << 4;
220                     expect |= s->code_mask[3] & 0x0f;
221 
222                     mask = s->code_mask[5] << 4;
223                     mask |= s->code_mask[7] & 0x0f;
224                         mask = ~mask & 0xff;
225 
226                     if ((frame->data[0] & mask) ==
227                         (expect & mask)) {
228                         return 1;
229                     }
230                 }
231 
232                 can_sja_dual_filter(&filter,
233                     s->code_mask + 2, s->code_mask + 6, 0);
234 
235                 if (can_bus_filter_match(&filter, frame->can_id)) {
236                     return 1;
237                 }
238 
239                 return 0;
240             }
241         }
242     }
243 
244     return 1;
245 }
246 
247 static void can_display_msg(const char *prefix, const qemu_can_frame *msg)
248 {
249     int i;
250     FILE *logfile = qemu_log_trylock();
251 
252     if (logfile) {
253         fprintf(logfile, "%s%03X [%01d] %s %s",
254                 prefix,
255                 msg->can_id & QEMU_CAN_EFF_MASK,
256                 msg->can_dlc,
257                 msg->can_id & QEMU_CAN_EFF_FLAG ? "EFF" : "SFF",
258                 msg->can_id & QEMU_CAN_RTR_FLAG ? "RTR" : "DAT");
259 
260         for (i = 0; i < msg->can_dlc; i++) {
261             fprintf(logfile, " %02X", msg->data[i]);
262         }
263         fprintf(logfile, "\n");
264         qemu_log_flush();
265         qemu_log_unlock(logfile);
266     }
267 }
268 
269 static void buff2frame_pel(const uint8_t *buff, qemu_can_frame *frame)
270 {
271     uint8_t i;
272 
273     frame->flags = 0;
274     frame->can_id = 0;
275     if (buff[0] & 0x40) { /* RTR */
276         frame->can_id = QEMU_CAN_RTR_FLAG;
277     }
278     frame->can_dlc = buff[0] & 0x0f;
279 
280     if (frame->can_dlc > 8) {
281         frame->can_dlc = 8;
282     }
283 
284     if (buff[0] & 0x80) { /* Extended */
285         frame->can_id |= QEMU_CAN_EFF_FLAG;
286         frame->can_id |= buff[1] << 21; /* ID.28~ID.21 */
287         frame->can_id |= buff[2] << 13; /* ID.20~ID.13 */
288         frame->can_id |= buff[3] <<  5;
289         frame->can_id |= buff[4] >>  3;
290         for (i = 0; i < frame->can_dlc; i++) {
291             frame->data[i] = buff[5 + i];
292         }
293         for (; i < 8; i++) {
294             frame->data[i] = 0;
295         }
296     } else {
297         frame->can_id |= buff[1] <<  3;
298         frame->can_id |= buff[2] >>  5;
299         for (i = 0; i < frame->can_dlc; i++) {
300             frame->data[i] = buff[3 + i];
301         }
302         for (; i < 8; i++) {
303             frame->data[i] = 0;
304         }
305     }
306 }
307 
308 
309 static void buff2frame_bas(const uint8_t *buff, qemu_can_frame *frame)
310 {
311     uint8_t i;
312 
313     frame->flags = 0;
314     frame->can_id = ((buff[0] << 3) & (0xff << 3)) + ((buff[1] >> 5) & 0x07);
315     if (buff[1] & 0x10) { /* RTR */
316         frame->can_id = QEMU_CAN_RTR_FLAG;
317     }
318     frame->can_dlc = buff[1] & 0x0f;
319 
320     if (frame->can_dlc > 8) {
321         frame->can_dlc = 8;
322     }
323 
324     for (i = 0; i < frame->can_dlc; i++) {
325         frame->data[i] = buff[2 + i];
326     }
327     for (; i < 8; i++) {
328         frame->data[i] = 0;
329     }
330 }
331 
332 
333 static int frame2buff_pel(const qemu_can_frame *frame, uint8_t *buff)
334 {
335     int i;
336     int dlen = frame->can_dlc;
337 
338     if (frame->can_id & QEMU_CAN_ERR_FLAG) { /* error frame, NOT support now. */
339         return -1;
340     }
341 
342     if (dlen > 8) {
343         return -1;
344     }
345 
346     buff[0] = 0x0f & frame->can_dlc; /* DLC */
347     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
348         buff[0] |= (1 << 6);
349     }
350     if (frame->can_id & QEMU_CAN_EFF_FLAG) { /* EFF */
351         buff[0] |= (1 << 7);
352         buff[1] = extract32(frame->can_id, 21, 8); /* ID.28~ID.21 */
353         buff[2] = extract32(frame->can_id, 13, 8); /* ID.20~ID.13 */
354         buff[3] = extract32(frame->can_id, 5, 8);  /* ID.12~ID.05 */
355         buff[4] = extract32(frame->can_id, 0, 5) << 3; /* ID.04~ID.00,xxx */
356         for (i = 0; i < dlen; i++) {
357             buff[5 + i] = frame->data[i];
358         }
359         return dlen + 5;
360     } else { /* SFF */
361         buff[1] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
362         buff[2] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
363         for (i = 0; i < dlen; i++) {
364             buff[3 + i] = frame->data[i];
365         }
366 
367         return dlen + 3;
368     }
369 
370     return -1;
371 }
372 
373 static int frame2buff_bas(const qemu_can_frame *frame, uint8_t *buff)
374 {
375     int i;
376     int dlen = frame->can_dlc;
377 
378      /*
379       * EFF, no support for BasicMode
380       * No use for Error frames now,
381       * they could be used in future to update SJA1000 error state
382       */
383     if ((frame->can_id & QEMU_CAN_EFF_FLAG) ||
384        (frame->can_id & QEMU_CAN_ERR_FLAG)) {
385         return -1;
386     }
387 
388     if (dlen > 8) {
389         return -1;
390     }
391 
392     buff[0] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
393     buff[1] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
394     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
395         buff[1] |= (1 << 4);
396     }
397     buff[1] |= frame->can_dlc & 0x0f;
398     for (i = 0; i < dlen; i++) {
399         buff[2 + i] = frame->data[i];
400     }
401 
402     return dlen + 2;
403 }
404 
405 static void can_sja_update_pel_irq(CanSJA1000State *s)
406 {
407     if (s->interrupt_en & s->interrupt_pel) {
408         qemu_irq_raise(s->irq);
409     } else {
410         qemu_irq_lower(s->irq);
411     }
412 }
413 
414 static void can_sja_update_bas_irq(CanSJA1000State *s)
415 {
416     if ((s->control >> 1) & s->interrupt_bas) {
417         qemu_irq_raise(s->irq);
418     } else {
419         qemu_irq_lower(s->irq);
420     }
421 }
422 
423 void can_sja_mem_write(CanSJA1000State *s, hwaddr addr, uint64_t val,
424                        unsigned size)
425 {
426     qemu_can_frame   frame;
427     uint32_t         tmp;
428     uint8_t          tmp8, count;
429 
430 
431     DPRINTF("write 0x%02llx addr 0x%02x\n",
432             (unsigned long long)val, (unsigned int)addr);
433 
434     if (addr > CAN_SJA_MEM_SIZE) {
435         return ;
436     }
437 
438     if (s->clock & 0x80) { /* PeliCAN Mode */
439         switch (addr) {
440         case SJA_MOD: /* Mode register */
441             s->mode = 0x1f & val;
442             if ((s->mode & 0x01) && ((val & 0x01) == 0)) {
443                 /* Go to operation mode from reset mode. */
444                 if (s->mode & (1 << 3)) { /* Single mode. */
445                     /* For EFF */
446                     can_sja_single_filter(&s->filter[0],
447                         s->code_mask + 0, s->code_mask + 4, 1);
448 
449                     /* For SFF */
450                     can_sja_single_filter(&s->filter[1],
451                         s->code_mask + 0, s->code_mask + 4, 0);
452 
453                     can_bus_client_set_filters(&s->bus_client, s->filter, 2);
454                 } else { /* Dual mode */
455                     /* For EFF */
456                     can_sja_dual_filter(&s->filter[0],
457                         s->code_mask + 0, s->code_mask + 4, 1);
458 
459                     can_sja_dual_filter(&s->filter[1],
460                         s->code_mask + 2, s->code_mask + 6, 1);
461 
462                     /* For SFF */
463                     can_sja_dual_filter(&s->filter[2],
464                         s->code_mask + 0, s->code_mask + 4, 0);
465 
466                     can_sja_dual_filter(&s->filter[3],
467                         s->code_mask + 2, s->code_mask + 6, 0);
468 
469                     can_bus_client_set_filters(&s->bus_client, s->filter, 4);
470                 }
471 
472                 s->rxmsg_cnt = 0;
473                 s->rx_cnt = 0;
474             }
475             break;
476 
477         case SJA_CMR: /* Command register. */
478             if (0x01 & val) { /* Send transmission request. */
479                 buff2frame_pel(s->tx_buff, &frame);
480                 if (DEBUG_FILTER) {
481                     can_display_msg("[cansja]: Tx request " , &frame);
482                 }
483 
484                 /*
485                  * Clear transmission complete status,
486                  * and Transmit Buffer Status.
487                  * write to the backends.
488                  */
489                 s->status_pel &= ~(3 << 2);
490 
491                 can_bus_client_send(&s->bus_client, &frame, 1);
492 
493                 /*
494                  * Set transmission complete status
495                  * and Transmit Buffer Status.
496                  */
497                 s->status_pel |= (3 << 2);
498 
499                 /* Clear transmit status. */
500                 s->status_pel &= ~(1 << 5);
501                 s->interrupt_pel |= 0x02;
502                 can_sja_update_pel_irq(s);
503             }
504             if (0x04 & val) { /* Release Receive Buffer */
505                 if (s->rxmsg_cnt <= 0) {
506                     break;
507                 }
508 
509                 tmp8 = s->rx_buff[s->rxbuf_start]; count = 0;
510                 if (tmp8 & (1 << 7)) { /* EFF */
511                     count += 2;
512                 }
513                 count += 3;
514                 if (!(tmp8 & (1 << 6))) { /* DATA */
515                     count += (tmp8 & 0x0f);
516                 }
517 
518                 if (DEBUG_FILTER) {
519                     qemu_log("[cansja]: message released from "
520                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
521                 }
522 
523                 s->rxbuf_start += count;
524                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
525 
526                 s->rx_cnt -= count;
527                 s->rxmsg_cnt--;
528                 if (s->rxmsg_cnt == 0) {
529                     s->status_pel &= ~(1 << 0);
530                     s->interrupt_pel &= ~(1 << 0);
531                     can_sja_update_pel_irq(s);
532                 }
533             }
534             if (0x08 & val) { /* Clear data overrun */
535                 s->status_pel &= ~(1 << 1);
536                 s->interrupt_pel &= ~(1 << 3);
537                 can_sja_update_pel_irq(s);
538             }
539             break;
540         case SJA_SR: /* Status register */
541         case SJA_IR: /* Interrupt register */
542             break; /* Do nothing */
543         case SJA_IER: /* Interrupt enable register */
544             s->interrupt_en = val;
545             break;
546         case 16: /* RX frame information addr16-28. */
547             s->status_pel |= (1 << 5); /* Set transmit status. */
548             /* fallthrough */
549         case 17 ... 28:
550             if (s->mode & 0x01) { /* Reset mode */
551                 if (addr < 24) {
552                     s->code_mask[addr - 16] = val;
553                 }
554             } else { /* Operation mode */
555                 s->tx_buff[addr - 16] = val; /* Store to TX buffer directly. */
556             }
557             break;
558         case SJA_CDR:
559             s->clock = val;
560             break;
561         }
562     } else { /* Basic Mode */
563         switch (addr) {
564         case SJA_BCAN_CTR: /* Control register, addr 0 */
565             if ((s->control & 0x01) && ((val & 0x01) == 0)) {
566                 /* Go to operation mode from reset mode. */
567                 s->filter[0].can_id = (s->code << 3) & (0xff << 3);
568                 tmp = (~(s->mask << 3)) & (0xff << 3);
569                 tmp |= QEMU_CAN_EFF_FLAG; /* Only Basic CAN Frame. */
570                 s->filter[0].can_mask = tmp;
571                 can_bus_client_set_filters(&s->bus_client, s->filter, 1);
572 
573                 s->rxmsg_cnt = 0;
574                 s->rx_cnt = 0;
575             } else if (!(s->control & 0x01) && !(val & 0x01)) {
576                 can_sja_software_reset(s);
577             }
578 
579             s->control = 0x1f & val;
580             break;
581         case SJA_BCAN_CMR: /* Command register, addr 1 */
582             if (0x01 & val) { /* Send transmission request. */
583                 buff2frame_bas(s->tx_buff, &frame);
584                 if (DEBUG_FILTER) {
585                     can_display_msg("[cansja]: Tx request " , &frame);
586                 }
587 
588                 /*
589                  * Clear transmission complete status,
590                  * and Transmit Buffer Status.
591                  */
592                 s->status_bas &= ~(3 << 2);
593 
594                 /* write to the backends. */
595                 can_bus_client_send(&s->bus_client, &frame, 1);
596 
597                 /*
598                  * Set transmission complete status,
599                  * and Transmit Buffer Status.
600                  */
601                 s->status_bas |= (3 << 2);
602 
603                 /* Clear transmit status. */
604                 s->status_bas &= ~(1 << 5);
605                 s->interrupt_bas |= 0x02;
606                 can_sja_update_bas_irq(s);
607             }
608             if (0x04 & val) { /* Release Receive Buffer */
609                 if (s->rxmsg_cnt <= 0) {
610                     break;
611                 }
612 
613                 tmp8 = s->rx_buff[(s->rxbuf_start + 1) % SJA_RCV_BUF_LEN];
614                 count = 2 + (tmp8 & 0x0f);
615 
616                 if (DEBUG_FILTER) {
617                     qemu_log("[cansja]: message released from "
618                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
619                 }
620 
621                 s->rxbuf_start += count;
622                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
623                 s->rx_cnt -= count;
624                 s->rxmsg_cnt--;
625 
626                 if (s->rxmsg_cnt == 0) {
627                     s->status_bas &= ~(1 << 0);
628                     s->interrupt_bas &= ~(1 << 0);
629                     can_sja_update_bas_irq(s);
630                 }
631             }
632             if (0x08 & val) { /* Clear data overrun */
633                 s->status_bas &= ~(1 << 1);
634                 s->interrupt_bas &= ~(1 << 3);
635                 can_sja_update_bas_irq(s);
636             }
637             break;
638         case 4:
639             s->code = val;
640             break;
641         case 5:
642             s->mask = val;
643             break;
644         case 10:
645             s->status_bas |= (1 << 5); /* Set transmit status. */
646             /* fallthrough */
647         case 11 ... 19:
648             if ((s->control & 0x01) == 0) { /* Operation mode */
649                 s->tx_buff[addr - 10] = val; /* Store to TX buffer directly. */
650             }
651             break;
652         case SJA_CDR:
653             s->clock = val;
654             break;
655         }
656     }
657 }
658 
659 uint64_t can_sja_mem_read(CanSJA1000State *s, hwaddr addr, unsigned size)
660 {
661     uint64_t temp = 0;
662 
663     DPRINTF("read addr 0x%02x ...\n", (unsigned int)addr);
664 
665     if (addr > CAN_SJA_MEM_SIZE) {
666         return 0;
667     }
668 
669     if (s->clock & 0x80) { /* PeliCAN Mode */
670         switch (addr) {
671         case SJA_MOD: /* Mode register, addr 0 */
672             temp = s->mode;
673             break;
674         case SJA_CMR: /* Command register, addr 1 */
675             temp = 0x00; /* Command register, cannot be read. */
676             break;
677         case SJA_SR: /* Status register, addr 2 */
678             temp = s->status_pel;
679             break;
680         case SJA_IR: /* Interrupt register, addr 3 */
681             temp = s->interrupt_pel;
682             s->interrupt_pel = 0;
683             if (s->rxmsg_cnt) {
684                 s->interrupt_pel |= (1 << 0); /* Receive interrupt. */
685             }
686             can_sja_update_pel_irq(s);
687             break;
688         case SJA_IER: /* Interrupt enable register, addr 4 */
689             temp = s->interrupt_en;
690             break;
691         case 5: /* Reserved */
692         case 6: /* Bus timing 0, hardware related, not support now. */
693         case 7: /* Bus timing 1, hardware related, not support now. */
694         case 8: /*
695                  * Output control register, hardware related,
696                  * not supported for now.
697                  */
698         case 9: /* Test. */
699         case 10 ... 15: /* Reserved */
700             temp = 0x00;
701             break;
702 
703         case 16 ... 28:
704             if (s->mode & 0x01) { /* Reset mode */
705                 if (addr < 24) {
706                     temp = s->code_mask[addr - 16];
707                 } else {
708                     temp = 0x00;
709                 }
710             } else { /* Operation mode */
711                 temp = s->rx_buff[(s->rxbuf_start + addr - 16) %
712                        SJA_RCV_BUF_LEN];
713             }
714             break;
715         case SJA_CDR:
716             temp = s->clock;
717             break;
718         default:
719             temp = 0xff;
720         }
721     } else { /* Basic Mode */
722         switch (addr) {
723         case SJA_BCAN_CTR: /* Control register, addr 0 */
724             temp = s->control;
725             break;
726         case SJA_BCAN_SR: /* Status register, addr 2 */
727             temp = s->status_bas;
728             break;
729         case SJA_BCAN_IR: /* Interrupt register, addr 3 */
730             temp = s->interrupt_bas;
731             s->interrupt_bas = 0;
732             if (s->rxmsg_cnt) {
733                 s->interrupt_bas |= (1 << 0); /* Receive interrupt. */
734             }
735             can_sja_update_bas_irq(s);
736             break;
737         case 4:
738             temp = s->code;
739             break;
740         case 5:
741             temp = s->mask;
742             break;
743         case 20 ... 29:
744             temp = s->rx_buff[(s->rxbuf_start + addr - 20) % SJA_RCV_BUF_LEN];
745             break;
746         case 31:
747             temp = s->clock;
748             break;
749         default:
750             temp = 0xff;
751             break;
752         }
753     }
754     DPRINTF("read addr 0x%02x, %d bytes, content 0x%02lx\n",
755             (int)addr, size, (long unsigned int)temp);
756 
757     return temp;
758 }
759 
760 bool can_sja_can_receive(CanBusClientState *client)
761 {
762     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
763 
764     if (s->clock & 0x80) { /* PeliCAN Mode */
765         if (s->mode & 0x01) { /* reset mode. */
766             return false;
767         }
768     } else { /* BasicCAN mode */
769         if (s->control & 0x01) {
770             return false;
771         }
772     }
773 
774     return true; /* always return true, when operation mode */
775 }
776 
777 ssize_t can_sja_receive(CanBusClientState *client, const qemu_can_frame *frames,
778                         size_t frames_cnt)
779 {
780     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
781     static uint8_t rcv[SJA_MSG_MAX_LEN];
782     int i;
783     int ret = -1;
784     const qemu_can_frame *frame = frames;
785 
786     if (frames_cnt <= 0) {
787         return 0;
788     }
789     if (frame->flags & QEMU_CAN_FRMF_TYPE_FD) {
790         if (DEBUG_FILTER) {
791             can_display_msg("[cansja]: ignor fd frame ", frame);
792         }
793         return 1;
794     }
795 
796     if (DEBUG_FILTER) {
797         can_display_msg("[cansja]: receive ", frame);
798     }
799 
800     if (s->clock & 0x80) { /* PeliCAN Mode */
801 
802         /* the CAN controller is receiving a message */
803         s->status_pel |= (1 << 4);
804 
805         if (can_sja_accept_filter(s, frame) == 0) {
806             s->status_pel &= ~(1 << 4);
807             if (DEBUG_FILTER) {
808                 qemu_log("[cansja]: filter rejects message\n");
809             }
810             return ret;
811         }
812 
813         ret = frame2buff_pel(frame, rcv);
814         if (ret < 0) {
815             s->status_pel &= ~(1 << 4);
816             if (DEBUG_FILTER) {
817                 qemu_log("[cansja]: message store failed\n");
818             }
819             return ret; /* maybe not support now. */
820         }
821 
822         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
823             s->status_pel |= (1 << 1); /* Overrun status */
824             s->interrupt_pel |= (1 << 3);
825             s->status_pel &= ~(1 << 4);
826             if (DEBUG_FILTER) {
827                 qemu_log("[cansja]: receive FIFO overrun\n");
828             }
829             can_sja_update_pel_irq(s);
830             return ret;
831         }
832         s->rx_cnt += ret;
833         s->rxmsg_cnt++;
834         if (DEBUG_FILTER) {
835             qemu_log("[cansja]: message stored in receive FIFO\n");
836         }
837 
838         for (i = 0; i < ret; i++) {
839             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
840         }
841         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
842 
843         s->status_pel |= 0x01; /* Set the Receive Buffer Status. DS-p23 */
844         s->interrupt_pel |= 0x01;
845         s->status_pel &= ~(1 << 4);
846         s->status_pel |= (1 << 0);
847         can_sja_update_pel_irq(s);
848     } else { /* BasicCAN mode */
849 
850         /* the CAN controller is receiving a message */
851         s->status_bas |= (1 << 4);
852 
853         ret = frame2buff_bas(frame, rcv);
854         if (ret < 0) {
855             s->status_bas &= ~(1 << 4);
856             if (DEBUG_FILTER) {
857                 qemu_log("[cansja]: message store failed\n");
858             }
859             return ret; /* maybe not support now. */
860         }
861 
862         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
863             s->status_bas |= (1 << 1); /* Overrun status */
864             s->status_bas &= ~(1 << 4);
865             s->interrupt_bas |= (1 << 3);
866             can_sja_update_bas_irq(s);
867             if (DEBUG_FILTER) {
868                 qemu_log("[cansja]: receive FIFO overrun\n");
869             }
870             return ret;
871         }
872         s->rx_cnt += ret;
873         s->rxmsg_cnt++;
874 
875         if (DEBUG_FILTER) {
876             qemu_log("[cansja]: message stored\n");
877         }
878 
879         for (i = 0; i < ret; i++) {
880             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
881         }
882         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
883 
884         s->status_bas |= 0x01; /* Set the Receive Buffer Status. DS-p15 */
885         s->status_bas &= ~(1 << 4);
886         s->interrupt_bas |= (1 << 0);
887         can_sja_update_bas_irq(s);
888     }
889     return 1;
890 }
891 
892 static CanBusClientInfo can_sja_bus_client_info = {
893     .can_receive = can_sja_can_receive,
894     .receive = can_sja_receive,
895 };
896 
897 
898 int can_sja_connect_to_bus(CanSJA1000State *s, CanBusState *bus)
899 {
900     s->bus_client.info = &can_sja_bus_client_info;
901 
902     if (!bus) {
903         return -EINVAL;
904     }
905 
906     if (can_bus_insert_client(bus, &s->bus_client) < 0) {
907         return -1;
908     }
909 
910     return 0;
911 }
912 
913 void can_sja_disconnect(CanSJA1000State *s)
914 {
915     can_bus_remove_client(&s->bus_client);
916 }
917 
918 int can_sja_init(CanSJA1000State *s, qemu_irq irq)
919 {
920     s->irq = irq;
921 
922     qemu_irq_lower(s->irq);
923 
924     can_sja_hardware_reset(s);
925 
926     return 0;
927 }
928 
929 const VMStateDescription vmstate_qemu_can_filter = {
930     .name = "qemu_can_filter",
931     .version_id = 1,
932     .minimum_version_id = 1,
933     .fields = (VMStateField[]) {
934         VMSTATE_UINT32(can_id, qemu_can_filter),
935         VMSTATE_UINT32(can_mask, qemu_can_filter),
936         VMSTATE_END_OF_LIST()
937     }
938 };
939 
940 static int can_sja_post_load(void *opaque, int version_id)
941 {
942     CanSJA1000State *s = opaque;
943     if (s->clock & 0x80) { /* PeliCAN Mode */
944         can_sja_update_pel_irq(s);
945     } else {
946         can_sja_update_bas_irq(s);
947     }
948     return 0;
949 }
950 
951 /* VMState is needed for live migration of QEMU images */
952 const VMStateDescription vmstate_can_sja = {
953     .name = "can_sja",
954     .version_id = 1,
955     .minimum_version_id = 1,
956     .post_load = can_sja_post_load,
957     .fields = (VMStateField[]) {
958         VMSTATE_UINT8(mode, CanSJA1000State),
959 
960         VMSTATE_UINT8(status_pel, CanSJA1000State),
961         VMSTATE_UINT8(interrupt_pel, CanSJA1000State),
962         VMSTATE_UINT8(interrupt_en, CanSJA1000State),
963         VMSTATE_UINT8(rxmsg_cnt, CanSJA1000State),
964         VMSTATE_UINT8(rxbuf_start, CanSJA1000State),
965         VMSTATE_UINT8(clock, CanSJA1000State),
966 
967         VMSTATE_BUFFER(code_mask, CanSJA1000State),
968         VMSTATE_BUFFER(tx_buff, CanSJA1000State),
969 
970         VMSTATE_BUFFER(rx_buff, CanSJA1000State),
971 
972         VMSTATE_UINT32(rx_ptr, CanSJA1000State),
973         VMSTATE_UINT32(rx_cnt, CanSJA1000State),
974 
975         VMSTATE_UINT8(control, CanSJA1000State),
976 
977         VMSTATE_UINT8(status_bas, CanSJA1000State),
978         VMSTATE_UINT8(interrupt_bas, CanSJA1000State),
979         VMSTATE_UINT8(code, CanSJA1000State),
980         VMSTATE_UINT8(mask, CanSJA1000State),
981 
982         VMSTATE_STRUCT_ARRAY(filter, CanSJA1000State, 4, 0,
983                              vmstate_qemu_can_filter, qemu_can_filter),
984 
985 
986         VMSTATE_END_OF_LIST()
987     }
988 };
989