xref: /openbmc/qemu/hw/net/can/can_sja1000.c (revision dcba65f8)
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 (buff[0] & 0x80) { /* Extended */
279         frame->can_id |= QEMU_CAN_EFF_FLAG;
280         frame->can_id |= buff[1] << 21; /* ID.28~ID.21 */
281         frame->can_id |= buff[2] << 13; /* ID.20~ID.13 */
282         frame->can_id |= buff[3] <<  5;
283         frame->can_id |= buff[4] >>  3;
284         for (i = 0; i < frame->can_dlc; i++) {
285             frame->data[i] = buff[5 + i];
286         }
287         for (; i < 8; i++) {
288             frame->data[i] = 0;
289         }
290     } else {
291         frame->can_id |= buff[1] <<  3;
292         frame->can_id |= buff[2] >>  5;
293         for (i = 0; i < frame->can_dlc; i++) {
294             frame->data[i] = buff[3 + i];
295         }
296         for (; i < 8; i++) {
297             frame->data[i] = 0;
298         }
299     }
300 }
301 
302 
303 static void buff2frame_bas(const uint8_t *buff, qemu_can_frame *frame)
304 {
305     uint8_t i;
306 
307     frame->flags = 0;
308     frame->can_id = ((buff[0] << 3) & (0xff << 3)) + ((buff[1] >> 5) & 0x07);
309     if (buff[1] & 0x10) { /* RTR */
310         frame->can_id = QEMU_CAN_RTR_FLAG;
311     }
312     frame->can_dlc = buff[1] & 0x0f;
313 
314     for (i = 0; i < frame->can_dlc; i++) {
315         frame->data[i] = buff[2 + i];
316     }
317     for (; i < 8; i++) {
318         frame->data[i] = 0;
319     }
320 }
321 
322 
323 static int frame2buff_pel(const qemu_can_frame *frame, uint8_t *buff)
324 {
325     int i;
326     int dlen = frame->can_dlc;
327 
328     if (frame->can_id & QEMU_CAN_ERR_FLAG) { /* error frame, NOT support now. */
329         return -1;
330     }
331 
332     if (dlen > 8) {
333         return -1;
334     }
335 
336     buff[0] = 0x0f & frame->can_dlc; /* DLC */
337     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
338         buff[0] |= (1 << 6);
339     }
340     if (frame->can_id & QEMU_CAN_EFF_FLAG) { /* EFF */
341         buff[0] |= (1 << 7);
342         buff[1] = extract32(frame->can_id, 21, 8); /* ID.28~ID.21 */
343         buff[2] = extract32(frame->can_id, 13, 8); /* ID.20~ID.13 */
344         buff[3] = extract32(frame->can_id, 5, 8);  /* ID.12~ID.05 */
345         buff[4] = extract32(frame->can_id, 0, 5) << 3; /* ID.04~ID.00,xxx */
346         for (i = 0; i < dlen; i++) {
347             buff[5 + i] = frame->data[i];
348         }
349         return dlen + 5;
350     } else { /* SFF */
351         buff[1] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
352         buff[2] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
353         for (i = 0; i < dlen; i++) {
354             buff[3 + i] = frame->data[i];
355         }
356 
357         return dlen + 3;
358     }
359 
360     return -1;
361 }
362 
363 static int frame2buff_bas(const qemu_can_frame *frame, uint8_t *buff)
364 {
365     int i;
366     int dlen = frame->can_dlc;
367 
368      /*
369       * EFF, no support for BasicMode
370       * No use for Error frames now,
371       * they could be used in future to update SJA1000 error state
372       */
373     if ((frame->can_id & QEMU_CAN_EFF_FLAG) ||
374        (frame->can_id & QEMU_CAN_ERR_FLAG)) {
375         return -1;
376     }
377 
378     if (dlen > 8) {
379         return -1;
380     }
381 
382     buff[0] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
383     buff[1] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
384     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
385         buff[1] |= (1 << 4);
386     }
387     buff[1] |= frame->can_dlc & 0x0f;
388     for (i = 0; i < dlen; i++) {
389         buff[2 + i] = frame->data[i];
390     }
391 
392     return dlen + 2;
393 }
394 
395 static void can_sja_update_pel_irq(CanSJA1000State *s)
396 {
397     if (s->interrupt_en & s->interrupt_pel) {
398         qemu_irq_raise(s->irq);
399     } else {
400         qemu_irq_lower(s->irq);
401     }
402 }
403 
404 static void can_sja_update_bas_irq(CanSJA1000State *s)
405 {
406     if ((s->control >> 1) & s->interrupt_bas) {
407         qemu_irq_raise(s->irq);
408     } else {
409         qemu_irq_lower(s->irq);
410     }
411 }
412 
413 void can_sja_mem_write(CanSJA1000State *s, hwaddr addr, uint64_t val,
414                        unsigned size)
415 {
416     qemu_can_frame   frame;
417     uint32_t         tmp;
418     uint8_t          tmp8, count;
419 
420 
421     DPRINTF("write 0x%02llx addr 0x%02x\n",
422             (unsigned long long)val, (unsigned int)addr);
423 
424     if (addr > CAN_SJA_MEM_SIZE) {
425         return ;
426     }
427 
428     if (s->clock & 0x80) { /* PeliCAN Mode */
429         switch (addr) {
430         case SJA_MOD: /* Mode register */
431             s->mode = 0x1f & val;
432             if ((s->mode & 0x01) && ((val & 0x01) == 0)) {
433                 /* Go to operation mode from reset mode. */
434                 if (s->mode & (1 << 3)) { /* Single mode. */
435                     /* For EFF */
436                     can_sja_single_filter(&s->filter[0],
437                         s->code_mask + 0, s->code_mask + 4, 1);
438 
439                     /* For SFF */
440                     can_sja_single_filter(&s->filter[1],
441                         s->code_mask + 0, s->code_mask + 4, 0);
442 
443                     can_bus_client_set_filters(&s->bus_client, s->filter, 2);
444                 } else { /* Dual mode */
445                     /* For EFF */
446                     can_sja_dual_filter(&s->filter[0],
447                         s->code_mask + 0, s->code_mask + 4, 1);
448 
449                     can_sja_dual_filter(&s->filter[1],
450                         s->code_mask + 2, s->code_mask + 6, 1);
451 
452                     /* For SFF */
453                     can_sja_dual_filter(&s->filter[2],
454                         s->code_mask + 0, s->code_mask + 4, 0);
455 
456                     can_sja_dual_filter(&s->filter[3],
457                         s->code_mask + 2, s->code_mask + 6, 0);
458 
459                     can_bus_client_set_filters(&s->bus_client, s->filter, 4);
460                 }
461 
462                 s->rxmsg_cnt = 0;
463                 s->rx_cnt = 0;
464             }
465             break;
466 
467         case SJA_CMR: /* Command register. */
468             if (0x01 & val) { /* Send transmission request. */
469                 buff2frame_pel(s->tx_buff, &frame);
470                 if (DEBUG_FILTER) {
471                     can_display_msg("[cansja]: Tx request " , &frame);
472                 }
473 
474                 /*
475                  * Clear transmission complete status,
476                  * and Transmit Buffer Status.
477                  * write to the backends.
478                  */
479                 s->status_pel &= ~(3 << 2);
480 
481                 can_bus_client_send(&s->bus_client, &frame, 1);
482 
483                 /*
484                  * Set transmission complete status
485                  * and Transmit Buffer Status.
486                  */
487                 s->status_pel |= (3 << 2);
488 
489                 /* Clear transmit status. */
490                 s->status_pel &= ~(1 << 5);
491                 s->interrupt_pel |= 0x02;
492                 can_sja_update_pel_irq(s);
493             }
494             if (0x04 & val) { /* Release Receive Buffer */
495                 if (s->rxmsg_cnt <= 0) {
496                     break;
497                 }
498 
499                 tmp8 = s->rx_buff[s->rxbuf_start]; count = 0;
500                 if (tmp8 & (1 << 7)) { /* EFF */
501                     count += 2;
502                 }
503                 count += 3;
504                 if (!(tmp8 & (1 << 6))) { /* DATA */
505                     count += (tmp8 & 0x0f);
506                 }
507 
508                 if (DEBUG_FILTER) {
509                     qemu_log("[cansja]: message released from "
510                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
511                 }
512 
513                 s->rxbuf_start += count;
514                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
515 
516                 s->rx_cnt -= count;
517                 s->rxmsg_cnt--;
518                 if (s->rxmsg_cnt == 0) {
519                     s->status_pel &= ~(1 << 0);
520                     s->interrupt_pel &= ~(1 << 0);
521                     can_sja_update_pel_irq(s);
522                 }
523             }
524             if (0x08 & val) { /* Clear data overrun */
525                 s->status_pel &= ~(1 << 1);
526                 s->interrupt_pel &= ~(1 << 3);
527                 can_sja_update_pel_irq(s);
528             }
529             break;
530         case SJA_SR: /* Status register */
531         case SJA_IR: /* Interrupt register */
532             break; /* Do nothing */
533         case SJA_IER: /* Interrupt enable register */
534             s->interrupt_en = val;
535             break;
536         case 16: /* RX frame information addr16-28. */
537             s->status_pel |= (1 << 5); /* Set transmit status. */
538             /* fallthrough */
539         case 17 ... 28:
540             if (s->mode & 0x01) { /* Reset mode */
541                 if (addr < 24) {
542                     s->code_mask[addr - 16] = val;
543                 }
544             } else { /* Operation mode */
545                 s->tx_buff[addr - 16] = val; /* Store to TX buffer directly. */
546             }
547             break;
548         case SJA_CDR:
549             s->clock = val;
550             break;
551         }
552     } else { /* Basic Mode */
553         switch (addr) {
554         case SJA_BCAN_CTR: /* Control register, addr 0 */
555             if ((s->control & 0x01) && ((val & 0x01) == 0)) {
556                 /* Go to operation mode from reset mode. */
557                 s->filter[0].can_id = (s->code << 3) & (0xff << 3);
558                 tmp = (~(s->mask << 3)) & (0xff << 3);
559                 tmp |= QEMU_CAN_EFF_FLAG; /* Only Basic CAN Frame. */
560                 s->filter[0].can_mask = tmp;
561                 can_bus_client_set_filters(&s->bus_client, s->filter, 1);
562 
563                 s->rxmsg_cnt = 0;
564                 s->rx_cnt = 0;
565             } else if (!(s->control & 0x01) && !(val & 0x01)) {
566                 can_sja_software_reset(s);
567             }
568 
569             s->control = 0x1f & val;
570             break;
571         case SJA_BCAN_CMR: /* Command register, addr 1 */
572             if (0x01 & val) { /* Send transmission request. */
573                 buff2frame_bas(s->tx_buff, &frame);
574                 if (DEBUG_FILTER) {
575                     can_display_msg("[cansja]: Tx request " , &frame);
576                 }
577 
578                 /*
579                  * Clear transmission complete status,
580                  * and Transmit Buffer Status.
581                  */
582                 s->status_bas &= ~(3 << 2);
583 
584                 /* write to the backends. */
585                 can_bus_client_send(&s->bus_client, &frame, 1);
586 
587                 /*
588                  * Set transmission complete status,
589                  * and Transmit Buffer Status.
590                  */
591                 s->status_bas |= (3 << 2);
592 
593                 /* Clear transmit status. */
594                 s->status_bas &= ~(1 << 5);
595                 s->interrupt_bas |= 0x02;
596                 can_sja_update_bas_irq(s);
597             }
598             if (0x04 & val) { /* Release Receive Buffer */
599                 if (s->rxmsg_cnt <= 0) {
600                     break;
601                 }
602 
603                 tmp8 = s->rx_buff[(s->rxbuf_start + 1) % SJA_RCV_BUF_LEN];
604                 count = 2 + (tmp8 & 0x0f);
605 
606                 if (DEBUG_FILTER) {
607                     qemu_log("[cansja]: message released from "
608                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
609                 }
610 
611                 s->rxbuf_start += count;
612                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
613                 s->rx_cnt -= count;
614                 s->rxmsg_cnt--;
615 
616                 if (s->rxmsg_cnt == 0) {
617                     s->status_bas &= ~(1 << 0);
618                     s->interrupt_bas &= ~(1 << 0);
619                     can_sja_update_bas_irq(s);
620                 }
621             }
622             if (0x08 & val) { /* Clear data overrun */
623                 s->status_bas &= ~(1 << 1);
624                 s->interrupt_bas &= ~(1 << 3);
625                 can_sja_update_bas_irq(s);
626             }
627             break;
628         case 4:
629             s->code = val;
630             break;
631         case 5:
632             s->mask = val;
633             break;
634         case 10:
635             s->status_bas |= (1 << 5); /* Set transmit status. */
636             /* fallthrough */
637         case 11 ... 19:
638             if ((s->control & 0x01) == 0) { /* Operation mode */
639                 s->tx_buff[addr - 10] = val; /* Store to TX buffer directly. */
640             }
641             break;
642         case SJA_CDR:
643             s->clock = val;
644             break;
645         }
646     }
647 }
648 
649 uint64_t can_sja_mem_read(CanSJA1000State *s, hwaddr addr, unsigned size)
650 {
651     uint64_t temp = 0;
652 
653     DPRINTF("read addr 0x%02x ...\n", (unsigned int)addr);
654 
655     if (addr > CAN_SJA_MEM_SIZE) {
656         return 0;
657     }
658 
659     if (s->clock & 0x80) { /* PeliCAN Mode */
660         switch (addr) {
661         case SJA_MOD: /* Mode register, addr 0 */
662             temp = s->mode;
663             break;
664         case SJA_CMR: /* Command register, addr 1 */
665             temp = 0x00; /* Command register, cannot be read. */
666             break;
667         case SJA_SR: /* Status register, addr 2 */
668             temp = s->status_pel;
669             break;
670         case SJA_IR: /* Interrupt register, addr 3 */
671             temp = s->interrupt_pel;
672             s->interrupt_pel = 0;
673             if (s->rxmsg_cnt) {
674                 s->interrupt_pel |= (1 << 0); /* Receive interrupt. */
675             }
676             can_sja_update_pel_irq(s);
677             break;
678         case SJA_IER: /* Interrupt enable register, addr 4 */
679             temp = s->interrupt_en;
680             break;
681         case 5: /* Reserved */
682         case 6: /* Bus timing 0, hardware related, not support now. */
683         case 7: /* Bus timing 1, hardware related, not support now. */
684         case 8: /*
685                  * Output control register, hardware related,
686                  * not supported for now.
687                  */
688         case 9: /* Test. */
689         case 10 ... 15: /* Reserved */
690             temp = 0x00;
691             break;
692 
693         case 16 ... 28:
694             if (s->mode & 0x01) { /* Reset mode */
695                 if (addr < 24) {
696                     temp = s->code_mask[addr - 16];
697                 } else {
698                     temp = 0x00;
699                 }
700             } else { /* Operation mode */
701                 temp = s->rx_buff[(s->rxbuf_start + addr - 16) %
702                        SJA_RCV_BUF_LEN];
703             }
704             break;
705         case SJA_CDR:
706             temp = s->clock;
707             break;
708         default:
709             temp = 0xff;
710         }
711     } else { /* Basic Mode */
712         switch (addr) {
713         case SJA_BCAN_CTR: /* Control register, addr 0 */
714             temp = s->control;
715             break;
716         case SJA_BCAN_SR: /* Status register, addr 2 */
717             temp = s->status_bas;
718             break;
719         case SJA_BCAN_IR: /* Interrupt register, addr 3 */
720             temp = s->interrupt_bas;
721             s->interrupt_bas = 0;
722             if (s->rxmsg_cnt) {
723                 s->interrupt_bas |= (1 << 0); /* Receive interrupt. */
724             }
725             can_sja_update_bas_irq(s);
726             break;
727         case 4:
728             temp = s->code;
729             break;
730         case 5:
731             temp = s->mask;
732             break;
733         case 20 ... 29:
734             temp = s->rx_buff[(s->rxbuf_start + addr - 20) % SJA_RCV_BUF_LEN];
735             break;
736         case 31:
737             temp = s->clock;
738             break;
739         default:
740             temp = 0xff;
741             break;
742         }
743     }
744     DPRINTF("read addr 0x%02x, %d bytes, content 0x%02lx\n",
745             (int)addr, size, (long unsigned int)temp);
746 
747     return temp;
748 }
749 
750 bool can_sja_can_receive(CanBusClientState *client)
751 {
752     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
753 
754     if (s->clock & 0x80) { /* PeliCAN Mode */
755         if (s->mode & 0x01) { /* reset mode. */
756             return false;
757         }
758     } else { /* BasicCAN mode */
759         if (s->control & 0x01) {
760             return false;
761         }
762     }
763 
764     return true; /* always return true, when operation mode */
765 }
766 
767 ssize_t can_sja_receive(CanBusClientState *client, const qemu_can_frame *frames,
768                         size_t frames_cnt)
769 {
770     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
771     static uint8_t rcv[SJA_MSG_MAX_LEN];
772     int i;
773     int ret = -1;
774     const qemu_can_frame *frame = frames;
775 
776     if (frames_cnt <= 0) {
777         return 0;
778     }
779     if (frame->flags & QEMU_CAN_FRMF_TYPE_FD) {
780         if (DEBUG_FILTER) {
781             can_display_msg("[cansja]: ignor fd frame ", frame);
782         }
783         return 1;
784     }
785 
786     if (DEBUG_FILTER) {
787         can_display_msg("[cansja]: receive ", frame);
788     }
789 
790     if (s->clock & 0x80) { /* PeliCAN Mode */
791 
792         /* the CAN controller is receiving a message */
793         s->status_pel |= (1 << 4);
794 
795         if (can_sja_accept_filter(s, frame) == 0) {
796             s->status_pel &= ~(1 << 4);
797             if (DEBUG_FILTER) {
798                 qemu_log("[cansja]: filter rejects message\n");
799             }
800             return ret;
801         }
802 
803         ret = frame2buff_pel(frame, rcv);
804         if (ret < 0) {
805             s->status_pel &= ~(1 << 4);
806             if (DEBUG_FILTER) {
807                 qemu_log("[cansja]: message store failed\n");
808             }
809             return ret; /* maybe not support now. */
810         }
811 
812         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
813             s->status_pel |= (1 << 1); /* Overrun status */
814             s->interrupt_pel |= (1 << 3);
815             s->status_pel &= ~(1 << 4);
816             if (DEBUG_FILTER) {
817                 qemu_log("[cansja]: receive FIFO overrun\n");
818             }
819             can_sja_update_pel_irq(s);
820             return ret;
821         }
822         s->rx_cnt += ret;
823         s->rxmsg_cnt++;
824         if (DEBUG_FILTER) {
825             qemu_log("[cansja]: message stored in receive FIFO\n");
826         }
827 
828         for (i = 0; i < ret; i++) {
829             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
830         }
831         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
832 
833         s->status_pel |= 0x01; /* Set the Receive Buffer Status. DS-p23 */
834         s->interrupt_pel |= 0x01;
835         s->status_pel &= ~(1 << 4);
836         s->status_pel |= (1 << 0);
837         can_sja_update_pel_irq(s);
838     } else { /* BasicCAN mode */
839 
840         /* the CAN controller is receiving a message */
841         s->status_bas |= (1 << 4);
842 
843         ret = frame2buff_bas(frame, rcv);
844         if (ret < 0) {
845             s->status_bas &= ~(1 << 4);
846             if (DEBUG_FILTER) {
847                 qemu_log("[cansja]: message store failed\n");
848             }
849             return ret; /* maybe not support now. */
850         }
851 
852         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
853             s->status_bas |= (1 << 1); /* Overrun status */
854             s->status_bas &= ~(1 << 4);
855             s->interrupt_bas |= (1 << 3);
856             can_sja_update_bas_irq(s);
857             if (DEBUG_FILTER) {
858                 qemu_log("[cansja]: receive FIFO overrun\n");
859             }
860             return ret;
861         }
862         s->rx_cnt += ret;
863         s->rxmsg_cnt++;
864 
865         if (DEBUG_FILTER) {
866             qemu_log("[cansja]: message stored\n");
867         }
868 
869         for (i = 0; i < ret; i++) {
870             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
871         }
872         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
873 
874         s->status_bas |= 0x01; /* Set the Receive Buffer Status. DS-p15 */
875         s->status_bas &= ~(1 << 4);
876         s->interrupt_bas |= (1 << 0);
877         can_sja_update_bas_irq(s);
878     }
879     return 1;
880 }
881 
882 static CanBusClientInfo can_sja_bus_client_info = {
883     .can_receive = can_sja_can_receive,
884     .receive = can_sja_receive,
885 };
886 
887 
888 int can_sja_connect_to_bus(CanSJA1000State *s, CanBusState *bus)
889 {
890     s->bus_client.info = &can_sja_bus_client_info;
891 
892     if (!bus) {
893         return -EINVAL;
894     }
895 
896     if (can_bus_insert_client(bus, &s->bus_client) < 0) {
897         return -1;
898     }
899 
900     return 0;
901 }
902 
903 void can_sja_disconnect(CanSJA1000State *s)
904 {
905     can_bus_remove_client(&s->bus_client);
906 }
907 
908 int can_sja_init(CanSJA1000State *s, qemu_irq irq)
909 {
910     s->irq = irq;
911 
912     qemu_irq_lower(s->irq);
913 
914     can_sja_hardware_reset(s);
915 
916     return 0;
917 }
918 
919 const VMStateDescription vmstate_qemu_can_filter = {
920     .name = "qemu_can_filter",
921     .version_id = 1,
922     .minimum_version_id = 1,
923     .minimum_version_id_old = 1,
924     .fields = (VMStateField[]) {
925         VMSTATE_UINT32(can_id, qemu_can_filter),
926         VMSTATE_UINT32(can_mask, qemu_can_filter),
927         VMSTATE_END_OF_LIST()
928     }
929 };
930 
931 static int can_sja_post_load(void *opaque, int version_id)
932 {
933     CanSJA1000State *s = opaque;
934     if (s->clock & 0x80) { /* PeliCAN Mode */
935         can_sja_update_pel_irq(s);
936     } else {
937         can_sja_update_bas_irq(s);
938     }
939     return 0;
940 }
941 
942 /* VMState is needed for live migration of QEMU images */
943 const VMStateDescription vmstate_can_sja = {
944     .name = "can_sja",
945     .version_id = 1,
946     .minimum_version_id = 1,
947     .minimum_version_id_old = 1,
948     .post_load = can_sja_post_load,
949     .fields = (VMStateField[]) {
950         VMSTATE_UINT8(mode, CanSJA1000State),
951 
952         VMSTATE_UINT8(status_pel, CanSJA1000State),
953         VMSTATE_UINT8(interrupt_pel, CanSJA1000State),
954         VMSTATE_UINT8(interrupt_en, CanSJA1000State),
955         VMSTATE_UINT8(rxmsg_cnt, CanSJA1000State),
956         VMSTATE_UINT8(rxbuf_start, CanSJA1000State),
957         VMSTATE_UINT8(clock, CanSJA1000State),
958 
959         VMSTATE_BUFFER(code_mask, CanSJA1000State),
960         VMSTATE_BUFFER(tx_buff, CanSJA1000State),
961 
962         VMSTATE_BUFFER(rx_buff, CanSJA1000State),
963 
964         VMSTATE_UINT32(rx_ptr, CanSJA1000State),
965         VMSTATE_UINT32(rx_cnt, CanSJA1000State),
966 
967         VMSTATE_UINT8(control, CanSJA1000State),
968 
969         VMSTATE_UINT8(status_bas, CanSJA1000State),
970         VMSTATE_UINT8(interrupt_bas, CanSJA1000State),
971         VMSTATE_UINT8(code, CanSJA1000State),
972         VMSTATE_UINT8(mask, CanSJA1000State),
973 
974         VMSTATE_STRUCT_ARRAY(filter, CanSJA1000State, 4, 0,
975                              vmstate_qemu_can_filter, qemu_can_filter),
976 
977 
978         VMSTATE_END_OF_LIST()
979     }
980 };
981