xref: /openbmc/qemu/hw/net/can/can_sja1000.c (revision 20a4f14f)
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->can_id = 0;
272     if (buff[0] & 0x40) { /* RTR */
273         frame->can_id = QEMU_CAN_RTR_FLAG;
274     }
275     frame->can_dlc = buff[0] & 0x0f;
276 
277     if (buff[0] & 0x80) { /* Extended */
278         frame->can_id |= QEMU_CAN_EFF_FLAG;
279         frame->can_id |= buff[1] << 21; /* ID.28~ID.21 */
280         frame->can_id |= buff[2] << 13; /* ID.20~ID.13 */
281         frame->can_id |= buff[3] <<  5;
282         frame->can_id |= buff[4] >>  3;
283         for (i = 0; i < frame->can_dlc; i++) {
284             frame->data[i] = buff[5 + i];
285         }
286         for (; i < 8; i++) {
287             frame->data[i] = 0;
288         }
289     } else {
290         frame->can_id |= buff[1] <<  3;
291         frame->can_id |= buff[2] >>  5;
292         for (i = 0; i < frame->can_dlc; i++) {
293             frame->data[i] = buff[3 + i];
294         }
295         for (; i < 8; i++) {
296             frame->data[i] = 0;
297         }
298     }
299 }
300 
301 
302 static void buff2frame_bas(const uint8_t *buff, qemu_can_frame *frame)
303 {
304     uint8_t i;
305 
306     frame->can_id = ((buff[0] << 3) & (0xff << 3)) + ((buff[1] >> 5) & 0x07);
307     if (buff[1] & 0x10) { /* RTR */
308         frame->can_id = QEMU_CAN_RTR_FLAG;
309     }
310     frame->can_dlc = buff[1] & 0x0f;
311 
312     for (i = 0; i < frame->can_dlc; i++) {
313         frame->data[i] = buff[2 + i];
314     }
315     for (; i < 8; i++) {
316         frame->data[i] = 0;
317     }
318 }
319 
320 
321 static int frame2buff_pel(const qemu_can_frame *frame, uint8_t *buff)
322 {
323     int i;
324 
325     if (frame->can_id & QEMU_CAN_ERR_FLAG) { /* error frame, NOT support now. */
326         return -1;
327     }
328 
329     buff[0] = 0x0f & frame->can_dlc; /* DLC */
330     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
331         buff[0] |= (1 << 6);
332     }
333     if (frame->can_id & QEMU_CAN_EFF_FLAG) { /* EFF */
334         buff[0] |= (1 << 7);
335         buff[1] = extract32(frame->can_id, 21, 8); /* ID.28~ID.21 */
336         buff[2] = extract32(frame->can_id, 13, 8); /* ID.20~ID.13 */
337         buff[3] = extract32(frame->can_id, 5, 8);  /* ID.12~ID.05 */
338         buff[4] = extract32(frame->can_id, 0, 5) << 3; /* ID.04~ID.00,xxx */
339         for (i = 0; i < frame->can_dlc; i++) {
340             buff[5 + i] = frame->data[i];
341         }
342         return frame->can_dlc + 5;
343     } else { /* SFF */
344         buff[1] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
345         buff[2] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
346         for (i = 0; i < frame->can_dlc; i++) {
347             buff[3 + i] = frame->data[i];
348         }
349 
350         return frame->can_dlc + 3;
351     }
352 
353     return -1;
354 }
355 
356 static int frame2buff_bas(const qemu_can_frame *frame, uint8_t *buff)
357 {
358     int i;
359 
360      /*
361       * EFF, no support for BasicMode
362       * No use for Error frames now,
363       * they could be used in future to update SJA1000 error state
364       */
365     if ((frame->can_id & QEMU_CAN_EFF_FLAG) ||
366        (frame->can_id & QEMU_CAN_ERR_FLAG)) {
367         return -1;
368     }
369 
370     buff[0] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
371     buff[1] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
372     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
373         buff[1] |= (1 << 4);
374     }
375     buff[1] |= frame->can_dlc & 0x0f;
376     for (i = 0; i < frame->can_dlc; i++) {
377         buff[2 + i] = frame->data[i];
378     }
379 
380     return frame->can_dlc + 2;
381 }
382 
383 static void can_sja_update_pel_irq(CanSJA1000State *s)
384 {
385     if (s->interrupt_en & s->interrupt_pel) {
386         qemu_irq_raise(s->irq);
387     } else {
388         qemu_irq_lower(s->irq);
389     }
390 }
391 
392 static void can_sja_update_bas_irq(CanSJA1000State *s)
393 {
394     if ((s->control >> 1) & s->interrupt_bas) {
395         qemu_irq_raise(s->irq);
396     } else {
397         qemu_irq_lower(s->irq);
398     }
399 }
400 
401 void can_sja_mem_write(CanSJA1000State *s, hwaddr addr, uint64_t val,
402                        unsigned size)
403 {
404     qemu_can_frame   frame;
405     uint32_t         tmp;
406     uint8_t          tmp8, count;
407 
408 
409     DPRINTF("write 0x%02llx addr 0x%02x\n",
410             (unsigned long long)val, (unsigned int)addr);
411 
412     if (addr > CAN_SJA_MEM_SIZE) {
413         return ;
414     }
415 
416     if (s->clock & 0x80) { /* PeliCAN Mode */
417         switch (addr) {
418         case SJA_MOD: /* Mode register */
419             s->mode = 0x1f & val;
420             if ((s->mode & 0x01) && ((val & 0x01) == 0)) {
421                 /* Go to operation mode from reset mode. */
422                 if (s->mode & (1 << 3)) { /* Single mode. */
423                     /* For EFF */
424                     can_sja_single_filter(&s->filter[0],
425                         s->code_mask + 0, s->code_mask + 4, 1);
426 
427                     /* For SFF */
428                     can_sja_single_filter(&s->filter[1],
429                         s->code_mask + 0, s->code_mask + 4, 0);
430 
431                     can_bus_client_set_filters(&s->bus_client, s->filter, 2);
432                 } else { /* Dual mode */
433                     /* For EFF */
434                     can_sja_dual_filter(&s->filter[0],
435                         s->code_mask + 0, s->code_mask + 4, 1);
436 
437                     can_sja_dual_filter(&s->filter[1],
438                         s->code_mask + 2, s->code_mask + 6, 1);
439 
440                     /* For SFF */
441                     can_sja_dual_filter(&s->filter[2],
442                         s->code_mask + 0, s->code_mask + 4, 0);
443 
444                     can_sja_dual_filter(&s->filter[3],
445                         s->code_mask + 2, s->code_mask + 6, 0);
446 
447                     can_bus_client_set_filters(&s->bus_client, s->filter, 4);
448                 }
449 
450                 s->rxmsg_cnt = 0;
451                 s->rx_cnt = 0;
452             }
453             break;
454 
455         case SJA_CMR: /* Command register. */
456             if (0x01 & val) { /* Send transmission request. */
457                 buff2frame_pel(s->tx_buff, &frame);
458                 if (DEBUG_FILTER) {
459                     can_display_msg("[cansja]: Tx request " , &frame);
460                 }
461 
462                 /*
463                  * Clear transmission complete status,
464                  * and Transmit Buffer Status.
465                  * write to the backends.
466                  */
467                 s->status_pel &= ~(3 << 2);
468 
469                 can_bus_client_send(&s->bus_client, &frame, 1);
470 
471                 /*
472                  * Set transmission complete status
473                  * and Transmit Buffer Status.
474                  */
475                 s->status_pel |= (3 << 2);
476 
477                 /* Clear transmit status. */
478                 s->status_pel &= ~(1 << 5);
479                 s->interrupt_pel |= 0x02;
480                 can_sja_update_pel_irq(s);
481             }
482             if (0x04 & val) { /* Release Receive Buffer */
483                 if (s->rxmsg_cnt <= 0) {
484                     break;
485                 }
486 
487                 tmp8 = s->rx_buff[s->rxbuf_start]; count = 0;
488                 if (tmp8 & (1 << 7)) { /* EFF */
489                     count += 2;
490                 }
491                 count += 3;
492                 if (!(tmp8 & (1 << 6))) { /* DATA */
493                     count += (tmp8 & 0x0f);
494                 }
495 
496                 if (DEBUG_FILTER) {
497                     qemu_log("[cansja]: message released from "
498                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
499                 }
500 
501                 s->rxbuf_start += count;
502                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
503 
504                 s->rx_cnt -= count;
505                 s->rxmsg_cnt--;
506                 if (s->rxmsg_cnt == 0) {
507                     s->status_pel &= ~(1 << 0);
508                     s->interrupt_pel &= ~(1 << 0);
509                     can_sja_update_pel_irq(s);
510                 }
511             }
512             if (0x08 & val) { /* Clear data overrun */
513                 s->status_pel &= ~(1 << 1);
514                 s->interrupt_pel &= ~(1 << 3);
515                 can_sja_update_pel_irq(s);
516             }
517             break;
518         case SJA_SR: /* Status register */
519         case SJA_IR: /* Interrupt register */
520             break; /* Do nothing */
521         case SJA_IER: /* Interrupt enable register */
522             s->interrupt_en = val;
523             break;
524         case 16: /* RX frame information addr16-28. */
525             s->status_pel |= (1 << 5); /* Set transmit status. */
526         case 17 ... 28:
527             if (s->mode & 0x01) { /* Reset mode */
528                 if (addr < 24) {
529                     s->code_mask[addr - 16] = val;
530                 }
531             } else { /* Operation mode */
532                 s->tx_buff[addr - 16] = val; /* Store to TX buffer directly. */
533             }
534             break;
535         case SJA_CDR:
536             s->clock = val;
537             break;
538         }
539     } else { /* Basic Mode */
540         switch (addr) {
541         case SJA_BCAN_CTR: /* Control register, addr 0 */
542             if ((s->control & 0x01) && ((val & 0x01) == 0)) {
543                 /* Go to operation mode from reset mode. */
544                 s->filter[0].can_id = (s->code << 3) & (0xff << 3);
545                 tmp = (~(s->mask << 3)) & (0xff << 3);
546                 tmp |= QEMU_CAN_EFF_FLAG; /* Only Basic CAN Frame. */
547                 s->filter[0].can_mask = tmp;
548                 can_bus_client_set_filters(&s->bus_client, s->filter, 1);
549 
550                 s->rxmsg_cnt = 0;
551                 s->rx_cnt = 0;
552             } else if (!(s->control & 0x01) && !(val & 0x01)) {
553                 can_sja_software_reset(s);
554             }
555 
556             s->control = 0x1f & val;
557             break;
558         case SJA_BCAN_CMR: /* Command register, addr 1 */
559             if (0x01 & val) { /* Send transmission request. */
560                 buff2frame_bas(s->tx_buff, &frame);
561                 if (DEBUG_FILTER) {
562                     can_display_msg("[cansja]: Tx request " , &frame);
563                 }
564 
565                 /*
566                  * Clear transmission complete status,
567                  * and Transmit Buffer Status.
568                  */
569                 s->status_bas &= ~(3 << 2);
570 
571                 /* write to the backends. */
572                 can_bus_client_send(&s->bus_client, &frame, 1);
573 
574                 /*
575                  * Set transmission complete status,
576                  * and Transmit Buffer Status.
577                  */
578                 s->status_bas |= (3 << 2);
579 
580                 /* Clear transmit status. */
581                 s->status_bas &= ~(1 << 5);
582                 s->interrupt_bas |= 0x02;
583                 can_sja_update_bas_irq(s);
584             }
585             if (0x04 & val) { /* Release Receive Buffer */
586                 if (s->rxmsg_cnt <= 0) {
587                     break;
588                 }
589 
590                 tmp8 = s->rx_buff[(s->rxbuf_start + 1) % SJA_RCV_BUF_LEN];
591                 count = 2 + (tmp8 & 0x0f);
592 
593                 if (DEBUG_FILTER) {
594                     qemu_log("[cansja]: message released from "
595                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
596                 }
597 
598                 s->rxbuf_start += count;
599                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
600                 s->rx_cnt -= count;
601                 s->rxmsg_cnt--;
602 
603                 if (s->rxmsg_cnt == 0) {
604                     s->status_bas &= ~(1 << 0);
605                     s->interrupt_bas &= ~(1 << 0);
606                     can_sja_update_bas_irq(s);
607                 }
608             }
609             if (0x08 & val) { /* Clear data overrun */
610                 s->status_bas &= ~(1 << 1);
611                 s->interrupt_bas &= ~(1 << 3);
612                 can_sja_update_bas_irq(s);
613             }
614             break;
615         case 4:
616             s->code = val;
617             break;
618         case 5:
619             s->mask = val;
620             break;
621         case 10:
622             s->status_bas |= (1 << 5); /* Set transmit status. */
623         case 11 ... 19:
624             if ((s->control & 0x01) == 0) { /* Operation mode */
625                 s->tx_buff[addr - 10] = val; /* Store to TX buffer directly. */
626             }
627             break;
628         case SJA_CDR:
629             s->clock = val;
630             break;
631         }
632     }
633 }
634 
635 uint64_t can_sja_mem_read(CanSJA1000State *s, hwaddr addr, unsigned size)
636 {
637     uint64_t temp = 0;
638 
639     DPRINTF("read addr 0x%02x ...\n", (unsigned int)addr);
640 
641     if (addr > CAN_SJA_MEM_SIZE) {
642         return 0;
643     }
644 
645     if (s->clock & 0x80) { /* PeliCAN Mode */
646         switch (addr) {
647         case SJA_MOD: /* Mode register, addr 0 */
648             temp = s->mode;
649             break;
650         case SJA_CMR: /* Command register, addr 1 */
651             temp = 0x00; /* Command register, cannot be read. */
652             break;
653         case SJA_SR: /* Status register, addr 2 */
654             temp = s->status_pel;
655             break;
656         case SJA_IR: /* Interrupt register, addr 3 */
657             temp = s->interrupt_pel;
658             s->interrupt_pel = 0;
659             if (s->rxmsg_cnt) {
660                 s->interrupt_pel |= (1 << 0); /* Receive interrupt. */
661             }
662             can_sja_update_pel_irq(s);
663             break;
664         case SJA_IER: /* Interrupt enable register, addr 4 */
665             temp = s->interrupt_en;
666             break;
667         case 5: /* Reserved */
668         case 6: /* Bus timing 0, hardware related, not support now. */
669         case 7: /* Bus timing 1, hardware related, not support now. */
670         case 8: /*
671                  * Output control register, hardware related,
672                  * not supported for now.
673                  */
674         case 9: /* Test. */
675         case 10 ... 15: /* Reserved */
676             temp = 0x00;
677             break;
678 
679         case 16 ... 28:
680             if (s->mode & 0x01) { /* Reset mode */
681                 if (addr < 24) {
682                     temp = s->code_mask[addr - 16];
683                 } else {
684                     temp = 0x00;
685                 }
686             } else { /* Operation mode */
687                 temp = s->rx_buff[(s->rxbuf_start + addr - 16) %
688                        SJA_RCV_BUF_LEN];
689             }
690             break;
691         case SJA_CDR:
692             temp = s->clock;
693             break;
694         default:
695             temp = 0xff;
696         }
697     } else { /* Basic Mode */
698         switch (addr) {
699         case SJA_BCAN_CTR: /* Control register, addr 0 */
700             temp = s->control;
701             break;
702         case SJA_BCAN_SR: /* Status register, addr 2 */
703             temp = s->status_bas;
704             break;
705         case SJA_BCAN_IR: /* Interrupt register, addr 3 */
706             temp = s->interrupt_bas;
707             s->interrupt_bas = 0;
708             if (s->rxmsg_cnt) {
709                 s->interrupt_bas |= (1 << 0); /* Receive interrupt. */
710             }
711             can_sja_update_bas_irq(s);
712             break;
713         case 4:
714             temp = s->code;
715             break;
716         case 5:
717             temp = s->mask;
718             break;
719         case 20 ... 29:
720             temp = s->rx_buff[(s->rxbuf_start + addr - 20) % SJA_RCV_BUF_LEN];
721             break;
722         case 31:
723             temp = s->clock;
724             break;
725         default:
726             temp = 0xff;
727             break;
728         }
729     }
730     DPRINTF("read addr 0x%02x, %d bytes, content 0x%02lx\n",
731             (int)addr, size, (long unsigned int)temp);
732 
733     return temp;
734 }
735 
736 bool can_sja_can_receive(CanBusClientState *client)
737 {
738     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
739 
740     if (s->clock & 0x80) { /* PeliCAN Mode */
741         if (s->mode & 0x01) { /* reset mode. */
742             return false;
743         }
744     } else { /* BasicCAN mode */
745         if (s->control & 0x01) {
746             return false;
747         }
748     }
749 
750     return true; /* always return true, when operation mode */
751 }
752 
753 ssize_t can_sja_receive(CanBusClientState *client, const qemu_can_frame *frames,
754                         size_t frames_cnt)
755 {
756     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
757     static uint8_t rcv[SJA_MSG_MAX_LEN];
758     int i;
759     int ret = -1;
760     const qemu_can_frame *frame = frames;
761 
762     if (frames_cnt <= 0) {
763         return 0;
764     }
765     if (DEBUG_FILTER) {
766         can_display_msg("[cansja]: receive ", frame);
767     }
768 
769     if (s->clock & 0x80) { /* PeliCAN Mode */
770 
771         /* the CAN controller is receiving a message */
772         s->status_pel |= (1 << 4);
773 
774         if (can_sja_accept_filter(s, frame) == 0) {
775             s->status_pel &= ~(1 << 4);
776             if (DEBUG_FILTER) {
777                 qemu_log("[cansja]: filter rejects message\n");
778             }
779             return ret;
780         }
781 
782         ret = frame2buff_pel(frame, rcv);
783         if (ret < 0) {
784             s->status_pel &= ~(1 << 4);
785             if (DEBUG_FILTER) {
786                 qemu_log("[cansja]: message store failed\n");
787             }
788             return ret; /* maybe not support now. */
789         }
790 
791         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
792             s->status_pel |= (1 << 1); /* Overrun status */
793             s->interrupt_pel |= (1 << 3);
794             s->status_pel &= ~(1 << 4);
795             if (DEBUG_FILTER) {
796                 qemu_log("[cansja]: receive FIFO overrun\n");
797             }
798             can_sja_update_pel_irq(s);
799             return ret;
800         }
801         s->rx_cnt += ret;
802         s->rxmsg_cnt++;
803         if (DEBUG_FILTER) {
804             qemu_log("[cansja]: message stored in receive FIFO\n");
805         }
806 
807         for (i = 0; i < ret; i++) {
808             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
809         }
810         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
811 
812         s->status_pel |= 0x01; /* Set the Receive Buffer Status. DS-p23 */
813         s->interrupt_pel |= 0x01;
814         s->status_pel &= ~(1 << 4);
815         s->status_pel |= (1 << 0);
816         can_sja_update_pel_irq(s);
817     } else { /* BasicCAN mode */
818 
819         /* the CAN controller is receiving a message */
820         s->status_bas |= (1 << 4);
821 
822         ret = frame2buff_bas(frame, rcv);
823         if (ret < 0) {
824             s->status_bas &= ~(1 << 4);
825             if (DEBUG_FILTER) {
826                 qemu_log("[cansja]: message store failed\n");
827             }
828             return ret; /* maybe not support now. */
829         }
830 
831         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
832             s->status_bas |= (1 << 1); /* Overrun status */
833             s->status_bas &= ~(1 << 4);
834             s->interrupt_bas |= (1 << 3);
835             can_sja_update_bas_irq(s);
836             if (DEBUG_FILTER) {
837                 qemu_log("[cansja]: receive FIFO overrun\n");
838             }
839             return ret;
840         }
841         s->rx_cnt += ret;
842         s->rxmsg_cnt++;
843 
844         if (DEBUG_FILTER) {
845             qemu_log("[cansja]: message stored\n");
846         }
847 
848         for (i = 0; i < ret; i++) {
849             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
850         }
851         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
852 
853         s->status_bas |= 0x01; /* Set the Receive Buffer Status. DS-p15 */
854         s->status_bas &= ~(1 << 4);
855         s->interrupt_bas |= (1 << 0);
856         can_sja_update_bas_irq(s);
857     }
858     return 1;
859 }
860 
861 static CanBusClientInfo can_sja_bus_client_info = {
862     .can_receive = can_sja_can_receive,
863     .receive = can_sja_receive,
864 };
865 
866 
867 int can_sja_connect_to_bus(CanSJA1000State *s, CanBusState *bus)
868 {
869     s->bus_client.info = &can_sja_bus_client_info;
870 
871     if (!bus) {
872         return -EINVAL;
873     }
874 
875     if (can_bus_insert_client(bus, &s->bus_client) < 0) {
876         return -1;
877     }
878 
879     return 0;
880 }
881 
882 void can_sja_disconnect(CanSJA1000State *s)
883 {
884     can_bus_remove_client(&s->bus_client);
885 }
886 
887 int can_sja_init(CanSJA1000State *s, qemu_irq irq)
888 {
889     s->irq = irq;
890 
891     qemu_irq_lower(s->irq);
892 
893     can_sja_hardware_reset(s);
894 
895     return 0;
896 }
897 
898 const VMStateDescription vmstate_qemu_can_filter = {
899     .name = "qemu_can_filter",
900     .version_id = 1,
901     .minimum_version_id = 1,
902     .minimum_version_id_old = 1,
903     .fields = (VMStateField[]) {
904         VMSTATE_UINT32(can_id, qemu_can_filter),
905         VMSTATE_UINT32(can_mask, qemu_can_filter),
906         VMSTATE_END_OF_LIST()
907     }
908 };
909 
910 static int can_sja_post_load(void *opaque, int version_id)
911 {
912     CanSJA1000State *s = opaque;
913     if (s->clock & 0x80) { /* PeliCAN Mode */
914         can_sja_update_pel_irq(s);
915     } else {
916         can_sja_update_bas_irq(s);
917     }
918     return 0;
919 }
920 
921 /* VMState is needed for live migration of QEMU images */
922 const VMStateDescription vmstate_can_sja = {
923     .name = "can_sja",
924     .version_id = 1,
925     .minimum_version_id = 1,
926     .minimum_version_id_old = 1,
927     .post_load = can_sja_post_load,
928     .fields = (VMStateField[]) {
929         VMSTATE_UINT8(mode, CanSJA1000State),
930 
931         VMSTATE_UINT8(status_pel, CanSJA1000State),
932         VMSTATE_UINT8(interrupt_pel, CanSJA1000State),
933         VMSTATE_UINT8(interrupt_en, CanSJA1000State),
934         VMSTATE_UINT8(rxmsg_cnt, CanSJA1000State),
935         VMSTATE_UINT8(rxbuf_start, CanSJA1000State),
936         VMSTATE_UINT8(clock, CanSJA1000State),
937 
938         VMSTATE_BUFFER(code_mask, CanSJA1000State),
939         VMSTATE_BUFFER(tx_buff, CanSJA1000State),
940 
941         VMSTATE_BUFFER(rx_buff, CanSJA1000State),
942 
943         VMSTATE_UINT32(rx_ptr, CanSJA1000State),
944         VMSTATE_UINT32(rx_cnt, CanSJA1000State),
945 
946         VMSTATE_UINT8(control, CanSJA1000State),
947 
948         VMSTATE_UINT8(status_bas, CanSJA1000State),
949         VMSTATE_UINT8(interrupt_bas, CanSJA1000State),
950         VMSTATE_UINT8(code, CanSJA1000State),
951         VMSTATE_UINT8(mask, CanSJA1000State),
952 
953         VMSTATE_STRUCT_ARRAY(filter, CanSJA1000State, 4, 0,
954                              vmstate_qemu_can_filter, qemu_can_filter),
955 
956 
957         VMSTATE_END_OF_LIST()
958     }
959 };
960