xref: /openbmc/qemu/hw/net/can/can_sja1000.c (revision 43709a0c)
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_lock();
251 
252     qemu_log("%s%03X [%01d] %s %s",
253              prefix,
254              msg->can_id & QEMU_CAN_EFF_MASK,
255              msg->can_dlc,
256              msg->can_id & QEMU_CAN_EFF_FLAG ? "EFF" : "SFF",
257              msg->can_id & QEMU_CAN_RTR_FLAG ? "RTR" : "DAT");
258 
259     for (i = 0; i < msg->can_dlc; i++) {
260         qemu_log(" %02X", msg->data[i]);
261     }
262     qemu_log("\n");
263     qemu_log_flush();
264     qemu_log_unlock(logfile);
265 }
266 
267 static void buff2frame_pel(const uint8_t *buff, qemu_can_frame *frame)
268 {
269     uint8_t i;
270 
271     frame->flags = 0;
272     frame->can_id = 0;
273     if (buff[0] & 0x40) { /* RTR */
274         frame->can_id = QEMU_CAN_RTR_FLAG;
275     }
276     frame->can_dlc = buff[0] & 0x0f;
277 
278     if (frame->can_dlc > 8) {
279         frame->can_dlc = 8;
280     }
281 
282     if (buff[0] & 0x80) { /* Extended */
283         frame->can_id |= QEMU_CAN_EFF_FLAG;
284         frame->can_id |= buff[1] << 21; /* ID.28~ID.21 */
285         frame->can_id |= buff[2] << 13; /* ID.20~ID.13 */
286         frame->can_id |= buff[3] <<  5;
287         frame->can_id |= buff[4] >>  3;
288         for (i = 0; i < frame->can_dlc; i++) {
289             frame->data[i] = buff[5 + i];
290         }
291         for (; i < 8; i++) {
292             frame->data[i] = 0;
293         }
294     } else {
295         frame->can_id |= buff[1] <<  3;
296         frame->can_id |= buff[2] >>  5;
297         for (i = 0; i < frame->can_dlc; i++) {
298             frame->data[i] = buff[3 + i];
299         }
300         for (; i < 8; i++) {
301             frame->data[i] = 0;
302         }
303     }
304 }
305 
306 
307 static void buff2frame_bas(const uint8_t *buff, qemu_can_frame *frame)
308 {
309     uint8_t i;
310 
311     frame->flags = 0;
312     frame->can_id = ((buff[0] << 3) & (0xff << 3)) + ((buff[1] >> 5) & 0x07);
313     if (buff[1] & 0x10) { /* RTR */
314         frame->can_id = QEMU_CAN_RTR_FLAG;
315     }
316     frame->can_dlc = buff[1] & 0x0f;
317 
318     if (frame->can_dlc > 8) {
319         frame->can_dlc = 8;
320     }
321 
322     for (i = 0; i < frame->can_dlc; i++) {
323         frame->data[i] = buff[2 + i];
324     }
325     for (; i < 8; i++) {
326         frame->data[i] = 0;
327     }
328 }
329 
330 
331 static int frame2buff_pel(const qemu_can_frame *frame, uint8_t *buff)
332 {
333     int i;
334     int dlen = frame->can_dlc;
335 
336     if (frame->can_id & QEMU_CAN_ERR_FLAG) { /* error frame, NOT support now. */
337         return -1;
338     }
339 
340     if (dlen > 8) {
341         return -1;
342     }
343 
344     buff[0] = 0x0f & frame->can_dlc; /* DLC */
345     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
346         buff[0] |= (1 << 6);
347     }
348     if (frame->can_id & QEMU_CAN_EFF_FLAG) { /* EFF */
349         buff[0] |= (1 << 7);
350         buff[1] = extract32(frame->can_id, 21, 8); /* ID.28~ID.21 */
351         buff[2] = extract32(frame->can_id, 13, 8); /* ID.20~ID.13 */
352         buff[3] = extract32(frame->can_id, 5, 8);  /* ID.12~ID.05 */
353         buff[4] = extract32(frame->can_id, 0, 5) << 3; /* ID.04~ID.00,xxx */
354         for (i = 0; i < dlen; i++) {
355             buff[5 + i] = frame->data[i];
356         }
357         return dlen + 5;
358     } else { /* SFF */
359         buff[1] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
360         buff[2] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
361         for (i = 0; i < dlen; i++) {
362             buff[3 + i] = frame->data[i];
363         }
364 
365         return dlen + 3;
366     }
367 
368     return -1;
369 }
370 
371 static int frame2buff_bas(const qemu_can_frame *frame, uint8_t *buff)
372 {
373     int i;
374     int dlen = frame->can_dlc;
375 
376      /*
377       * EFF, no support for BasicMode
378       * No use for Error frames now,
379       * they could be used in future to update SJA1000 error state
380       */
381     if ((frame->can_id & QEMU_CAN_EFF_FLAG) ||
382        (frame->can_id & QEMU_CAN_ERR_FLAG)) {
383         return -1;
384     }
385 
386     if (dlen > 8) {
387         return -1;
388     }
389 
390     buff[0] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
391     buff[1] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
392     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
393         buff[1] |= (1 << 4);
394     }
395     buff[1] |= frame->can_dlc & 0x0f;
396     for (i = 0; i < dlen; i++) {
397         buff[2 + i] = frame->data[i];
398     }
399 
400     return dlen + 2;
401 }
402 
403 static void can_sja_update_pel_irq(CanSJA1000State *s)
404 {
405     if (s->interrupt_en & s->interrupt_pel) {
406         qemu_irq_raise(s->irq);
407     } else {
408         qemu_irq_lower(s->irq);
409     }
410 }
411 
412 static void can_sja_update_bas_irq(CanSJA1000State *s)
413 {
414     if ((s->control >> 1) & s->interrupt_bas) {
415         qemu_irq_raise(s->irq);
416     } else {
417         qemu_irq_lower(s->irq);
418     }
419 }
420 
421 void can_sja_mem_write(CanSJA1000State *s, hwaddr addr, uint64_t val,
422                        unsigned size)
423 {
424     qemu_can_frame   frame;
425     uint32_t         tmp;
426     uint8_t          tmp8, count;
427 
428 
429     DPRINTF("write 0x%02llx addr 0x%02x\n",
430             (unsigned long long)val, (unsigned int)addr);
431 
432     if (addr > CAN_SJA_MEM_SIZE) {
433         return ;
434     }
435 
436     if (s->clock & 0x80) { /* PeliCAN Mode */
437         switch (addr) {
438         case SJA_MOD: /* Mode register */
439             s->mode = 0x1f & val;
440             if ((s->mode & 0x01) && ((val & 0x01) == 0)) {
441                 /* Go to operation mode from reset mode. */
442                 if (s->mode & (1 << 3)) { /* Single mode. */
443                     /* For EFF */
444                     can_sja_single_filter(&s->filter[0],
445                         s->code_mask + 0, s->code_mask + 4, 1);
446 
447                     /* For SFF */
448                     can_sja_single_filter(&s->filter[1],
449                         s->code_mask + 0, s->code_mask + 4, 0);
450 
451                     can_bus_client_set_filters(&s->bus_client, s->filter, 2);
452                 } else { /* Dual mode */
453                     /* For EFF */
454                     can_sja_dual_filter(&s->filter[0],
455                         s->code_mask + 0, s->code_mask + 4, 1);
456 
457                     can_sja_dual_filter(&s->filter[1],
458                         s->code_mask + 2, s->code_mask + 6, 1);
459 
460                     /* For SFF */
461                     can_sja_dual_filter(&s->filter[2],
462                         s->code_mask + 0, s->code_mask + 4, 0);
463 
464                     can_sja_dual_filter(&s->filter[3],
465                         s->code_mask + 2, s->code_mask + 6, 0);
466 
467                     can_bus_client_set_filters(&s->bus_client, s->filter, 4);
468                 }
469 
470                 s->rxmsg_cnt = 0;
471                 s->rx_cnt = 0;
472             }
473             break;
474 
475         case SJA_CMR: /* Command register. */
476             if (0x01 & val) { /* Send transmission request. */
477                 buff2frame_pel(s->tx_buff, &frame);
478                 if (DEBUG_FILTER) {
479                     can_display_msg("[cansja]: Tx request " , &frame);
480                 }
481 
482                 /*
483                  * Clear transmission complete status,
484                  * and Transmit Buffer Status.
485                  * write to the backends.
486                  */
487                 s->status_pel &= ~(3 << 2);
488 
489                 can_bus_client_send(&s->bus_client, &frame, 1);
490 
491                 /*
492                  * Set transmission complete status
493                  * and Transmit Buffer Status.
494                  */
495                 s->status_pel |= (3 << 2);
496 
497                 /* Clear transmit status. */
498                 s->status_pel &= ~(1 << 5);
499                 s->interrupt_pel |= 0x02;
500                 can_sja_update_pel_irq(s);
501             }
502             if (0x04 & val) { /* Release Receive Buffer */
503                 if (s->rxmsg_cnt <= 0) {
504                     break;
505                 }
506 
507                 tmp8 = s->rx_buff[s->rxbuf_start]; count = 0;
508                 if (tmp8 & (1 << 7)) { /* EFF */
509                     count += 2;
510                 }
511                 count += 3;
512                 if (!(tmp8 & (1 << 6))) { /* DATA */
513                     count += (tmp8 & 0x0f);
514                 }
515 
516                 if (DEBUG_FILTER) {
517                     qemu_log("[cansja]: message released from "
518                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
519                 }
520 
521                 s->rxbuf_start += count;
522                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
523 
524                 s->rx_cnt -= count;
525                 s->rxmsg_cnt--;
526                 if (s->rxmsg_cnt == 0) {
527                     s->status_pel &= ~(1 << 0);
528                     s->interrupt_pel &= ~(1 << 0);
529                     can_sja_update_pel_irq(s);
530                 }
531             }
532             if (0x08 & val) { /* Clear data overrun */
533                 s->status_pel &= ~(1 << 1);
534                 s->interrupt_pel &= ~(1 << 3);
535                 can_sja_update_pel_irq(s);
536             }
537             break;
538         case SJA_SR: /* Status register */
539         case SJA_IR: /* Interrupt register */
540             break; /* Do nothing */
541         case SJA_IER: /* Interrupt enable register */
542             s->interrupt_en = val;
543             break;
544         case 16: /* RX frame information addr16-28. */
545             s->status_pel |= (1 << 5); /* Set transmit status. */
546             /* fallthrough */
547         case 17 ... 28:
548             if (s->mode & 0x01) { /* Reset mode */
549                 if (addr < 24) {
550                     s->code_mask[addr - 16] = val;
551                 }
552             } else { /* Operation mode */
553                 s->tx_buff[addr - 16] = val; /* Store to TX buffer directly. */
554             }
555             break;
556         case SJA_CDR:
557             s->clock = val;
558             break;
559         }
560     } else { /* Basic Mode */
561         switch (addr) {
562         case SJA_BCAN_CTR: /* Control register, addr 0 */
563             if ((s->control & 0x01) && ((val & 0x01) == 0)) {
564                 /* Go to operation mode from reset mode. */
565                 s->filter[0].can_id = (s->code << 3) & (0xff << 3);
566                 tmp = (~(s->mask << 3)) & (0xff << 3);
567                 tmp |= QEMU_CAN_EFF_FLAG; /* Only Basic CAN Frame. */
568                 s->filter[0].can_mask = tmp;
569                 can_bus_client_set_filters(&s->bus_client, s->filter, 1);
570 
571                 s->rxmsg_cnt = 0;
572                 s->rx_cnt = 0;
573             } else if (!(s->control & 0x01) && !(val & 0x01)) {
574                 can_sja_software_reset(s);
575             }
576 
577             s->control = 0x1f & val;
578             break;
579         case SJA_BCAN_CMR: /* Command register, addr 1 */
580             if (0x01 & val) { /* Send transmission request. */
581                 buff2frame_bas(s->tx_buff, &frame);
582                 if (DEBUG_FILTER) {
583                     can_display_msg("[cansja]: Tx request " , &frame);
584                 }
585 
586                 /*
587                  * Clear transmission complete status,
588                  * and Transmit Buffer Status.
589                  */
590                 s->status_bas &= ~(3 << 2);
591 
592                 /* write to the backends. */
593                 can_bus_client_send(&s->bus_client, &frame, 1);
594 
595                 /*
596                  * Set transmission complete status,
597                  * and Transmit Buffer Status.
598                  */
599                 s->status_bas |= (3 << 2);
600 
601                 /* Clear transmit status. */
602                 s->status_bas &= ~(1 << 5);
603                 s->interrupt_bas |= 0x02;
604                 can_sja_update_bas_irq(s);
605             }
606             if (0x04 & val) { /* Release Receive Buffer */
607                 if (s->rxmsg_cnt <= 0) {
608                     break;
609                 }
610 
611                 tmp8 = s->rx_buff[(s->rxbuf_start + 1) % SJA_RCV_BUF_LEN];
612                 count = 2 + (tmp8 & 0x0f);
613 
614                 if (DEBUG_FILTER) {
615                     qemu_log("[cansja]: message released from "
616                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
617                 }
618 
619                 s->rxbuf_start += count;
620                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
621                 s->rx_cnt -= count;
622                 s->rxmsg_cnt--;
623 
624                 if (s->rxmsg_cnt == 0) {
625                     s->status_bas &= ~(1 << 0);
626                     s->interrupt_bas &= ~(1 << 0);
627                     can_sja_update_bas_irq(s);
628                 }
629             }
630             if (0x08 & val) { /* Clear data overrun */
631                 s->status_bas &= ~(1 << 1);
632                 s->interrupt_bas &= ~(1 << 3);
633                 can_sja_update_bas_irq(s);
634             }
635             break;
636         case 4:
637             s->code = val;
638             break;
639         case 5:
640             s->mask = val;
641             break;
642         case 10:
643             s->status_bas |= (1 << 5); /* Set transmit status. */
644             /* fallthrough */
645         case 11 ... 19:
646             if ((s->control & 0x01) == 0) { /* Operation mode */
647                 s->tx_buff[addr - 10] = val; /* Store to TX buffer directly. */
648             }
649             break;
650         case SJA_CDR:
651             s->clock = val;
652             break;
653         }
654     }
655 }
656 
657 uint64_t can_sja_mem_read(CanSJA1000State *s, hwaddr addr, unsigned size)
658 {
659     uint64_t temp = 0;
660 
661     DPRINTF("read addr 0x%02x ...\n", (unsigned int)addr);
662 
663     if (addr > CAN_SJA_MEM_SIZE) {
664         return 0;
665     }
666 
667     if (s->clock & 0x80) { /* PeliCAN Mode */
668         switch (addr) {
669         case SJA_MOD: /* Mode register, addr 0 */
670             temp = s->mode;
671             break;
672         case SJA_CMR: /* Command register, addr 1 */
673             temp = 0x00; /* Command register, cannot be read. */
674             break;
675         case SJA_SR: /* Status register, addr 2 */
676             temp = s->status_pel;
677             break;
678         case SJA_IR: /* Interrupt register, addr 3 */
679             temp = s->interrupt_pel;
680             s->interrupt_pel = 0;
681             if (s->rxmsg_cnt) {
682                 s->interrupt_pel |= (1 << 0); /* Receive interrupt. */
683             }
684             can_sja_update_pel_irq(s);
685             break;
686         case SJA_IER: /* Interrupt enable register, addr 4 */
687             temp = s->interrupt_en;
688             break;
689         case 5: /* Reserved */
690         case 6: /* Bus timing 0, hardware related, not support now. */
691         case 7: /* Bus timing 1, hardware related, not support now. */
692         case 8: /*
693                  * Output control register, hardware related,
694                  * not supported for now.
695                  */
696         case 9: /* Test. */
697         case 10 ... 15: /* Reserved */
698             temp = 0x00;
699             break;
700 
701         case 16 ... 28:
702             if (s->mode & 0x01) { /* Reset mode */
703                 if (addr < 24) {
704                     temp = s->code_mask[addr - 16];
705                 } else {
706                     temp = 0x00;
707                 }
708             } else { /* Operation mode */
709                 temp = s->rx_buff[(s->rxbuf_start + addr - 16) %
710                        SJA_RCV_BUF_LEN];
711             }
712             break;
713         case SJA_CDR:
714             temp = s->clock;
715             break;
716         default:
717             temp = 0xff;
718         }
719     } else { /* Basic Mode */
720         switch (addr) {
721         case SJA_BCAN_CTR: /* Control register, addr 0 */
722             temp = s->control;
723             break;
724         case SJA_BCAN_SR: /* Status register, addr 2 */
725             temp = s->status_bas;
726             break;
727         case SJA_BCAN_IR: /* Interrupt register, addr 3 */
728             temp = s->interrupt_bas;
729             s->interrupt_bas = 0;
730             if (s->rxmsg_cnt) {
731                 s->interrupt_bas |= (1 << 0); /* Receive interrupt. */
732             }
733             can_sja_update_bas_irq(s);
734             break;
735         case 4:
736             temp = s->code;
737             break;
738         case 5:
739             temp = s->mask;
740             break;
741         case 20 ... 29:
742             temp = s->rx_buff[(s->rxbuf_start + addr - 20) % SJA_RCV_BUF_LEN];
743             break;
744         case 31:
745             temp = s->clock;
746             break;
747         default:
748             temp = 0xff;
749             break;
750         }
751     }
752     DPRINTF("read addr 0x%02x, %d bytes, content 0x%02lx\n",
753             (int)addr, size, (long unsigned int)temp);
754 
755     return temp;
756 }
757 
758 bool can_sja_can_receive(CanBusClientState *client)
759 {
760     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
761 
762     if (s->clock & 0x80) { /* PeliCAN Mode */
763         if (s->mode & 0x01) { /* reset mode. */
764             return false;
765         }
766     } else { /* BasicCAN mode */
767         if (s->control & 0x01) {
768             return false;
769         }
770     }
771 
772     return true; /* always return true, when operation mode */
773 }
774 
775 ssize_t can_sja_receive(CanBusClientState *client, const qemu_can_frame *frames,
776                         size_t frames_cnt)
777 {
778     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
779     static uint8_t rcv[SJA_MSG_MAX_LEN];
780     int i;
781     int ret = -1;
782     const qemu_can_frame *frame = frames;
783 
784     if (frames_cnt <= 0) {
785         return 0;
786     }
787     if (frame->flags & QEMU_CAN_FRMF_TYPE_FD) {
788         if (DEBUG_FILTER) {
789             can_display_msg("[cansja]: ignor fd frame ", frame);
790         }
791         return 1;
792     }
793 
794     if (DEBUG_FILTER) {
795         can_display_msg("[cansja]: receive ", frame);
796     }
797 
798     if (s->clock & 0x80) { /* PeliCAN Mode */
799 
800         /* the CAN controller is receiving a message */
801         s->status_pel |= (1 << 4);
802 
803         if (can_sja_accept_filter(s, frame) == 0) {
804             s->status_pel &= ~(1 << 4);
805             if (DEBUG_FILTER) {
806                 qemu_log("[cansja]: filter rejects message\n");
807             }
808             return ret;
809         }
810 
811         ret = frame2buff_pel(frame, rcv);
812         if (ret < 0) {
813             s->status_pel &= ~(1 << 4);
814             if (DEBUG_FILTER) {
815                 qemu_log("[cansja]: message store failed\n");
816             }
817             return ret; /* maybe not support now. */
818         }
819 
820         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
821             s->status_pel |= (1 << 1); /* Overrun status */
822             s->interrupt_pel |= (1 << 3);
823             s->status_pel &= ~(1 << 4);
824             if (DEBUG_FILTER) {
825                 qemu_log("[cansja]: receive FIFO overrun\n");
826             }
827             can_sja_update_pel_irq(s);
828             return ret;
829         }
830         s->rx_cnt += ret;
831         s->rxmsg_cnt++;
832         if (DEBUG_FILTER) {
833             qemu_log("[cansja]: message stored in receive FIFO\n");
834         }
835 
836         for (i = 0; i < ret; i++) {
837             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
838         }
839         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
840 
841         s->status_pel |= 0x01; /* Set the Receive Buffer Status. DS-p23 */
842         s->interrupt_pel |= 0x01;
843         s->status_pel &= ~(1 << 4);
844         s->status_pel |= (1 << 0);
845         can_sja_update_pel_irq(s);
846     } else { /* BasicCAN mode */
847 
848         /* the CAN controller is receiving a message */
849         s->status_bas |= (1 << 4);
850 
851         ret = frame2buff_bas(frame, rcv);
852         if (ret < 0) {
853             s->status_bas &= ~(1 << 4);
854             if (DEBUG_FILTER) {
855                 qemu_log("[cansja]: message store failed\n");
856             }
857             return ret; /* maybe not support now. */
858         }
859 
860         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
861             s->status_bas |= (1 << 1); /* Overrun status */
862             s->status_bas &= ~(1 << 4);
863             s->interrupt_bas |= (1 << 3);
864             can_sja_update_bas_irq(s);
865             if (DEBUG_FILTER) {
866                 qemu_log("[cansja]: receive FIFO overrun\n");
867             }
868             return ret;
869         }
870         s->rx_cnt += ret;
871         s->rxmsg_cnt++;
872 
873         if (DEBUG_FILTER) {
874             qemu_log("[cansja]: message stored\n");
875         }
876 
877         for (i = 0; i < ret; i++) {
878             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
879         }
880         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
881 
882         s->status_bas |= 0x01; /* Set the Receive Buffer Status. DS-p15 */
883         s->status_bas &= ~(1 << 4);
884         s->interrupt_bas |= (1 << 0);
885         can_sja_update_bas_irq(s);
886     }
887     return 1;
888 }
889 
890 static CanBusClientInfo can_sja_bus_client_info = {
891     .can_receive = can_sja_can_receive,
892     .receive = can_sja_receive,
893 };
894 
895 
896 int can_sja_connect_to_bus(CanSJA1000State *s, CanBusState *bus)
897 {
898     s->bus_client.info = &can_sja_bus_client_info;
899 
900     if (!bus) {
901         return -EINVAL;
902     }
903 
904     if (can_bus_insert_client(bus, &s->bus_client) < 0) {
905         return -1;
906     }
907 
908     return 0;
909 }
910 
911 void can_sja_disconnect(CanSJA1000State *s)
912 {
913     can_bus_remove_client(&s->bus_client);
914 }
915 
916 int can_sja_init(CanSJA1000State *s, qemu_irq irq)
917 {
918     s->irq = irq;
919 
920     qemu_irq_lower(s->irq);
921 
922     can_sja_hardware_reset(s);
923 
924     return 0;
925 }
926 
927 const VMStateDescription vmstate_qemu_can_filter = {
928     .name = "qemu_can_filter",
929     .version_id = 1,
930     .minimum_version_id = 1,
931     .minimum_version_id_old = 1,
932     .fields = (VMStateField[]) {
933         VMSTATE_UINT32(can_id, qemu_can_filter),
934         VMSTATE_UINT32(can_mask, qemu_can_filter),
935         VMSTATE_END_OF_LIST()
936     }
937 };
938 
939 static int can_sja_post_load(void *opaque, int version_id)
940 {
941     CanSJA1000State *s = opaque;
942     if (s->clock & 0x80) { /* PeliCAN Mode */
943         can_sja_update_pel_irq(s);
944     } else {
945         can_sja_update_bas_irq(s);
946     }
947     return 0;
948 }
949 
950 /* VMState is needed for live migration of QEMU images */
951 const VMStateDescription vmstate_can_sja = {
952     .name = "can_sja",
953     .version_id = 1,
954     .minimum_version_id = 1,
955     .minimum_version_id_old = 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