xref: /qemu/hw/net/can/can_sja1000.c (revision d44948ccbd56cde7be989da5cc872b0c05bf6224)
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 
327     if (frame->can_id & QEMU_CAN_ERR_FLAG) { /* error frame, NOT support now. */
328         return -1;
329     }
330 
331     buff[0] = 0x0f & frame->can_dlc; /* DLC */
332     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
333         buff[0] |= (1 << 6);
334     }
335     if (frame->can_id & QEMU_CAN_EFF_FLAG) { /* EFF */
336         buff[0] |= (1 << 7);
337         buff[1] = extract32(frame->can_id, 21, 8); /* ID.28~ID.21 */
338         buff[2] = extract32(frame->can_id, 13, 8); /* ID.20~ID.13 */
339         buff[3] = extract32(frame->can_id, 5, 8);  /* ID.12~ID.05 */
340         buff[4] = extract32(frame->can_id, 0, 5) << 3; /* ID.04~ID.00,xxx */
341         for (i = 0; i < frame->can_dlc; i++) {
342             buff[5 + i] = frame->data[i];
343         }
344         return frame->can_dlc + 5;
345     } else { /* SFF */
346         buff[1] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
347         buff[2] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
348         for (i = 0; i < frame->can_dlc; i++) {
349             buff[3 + i] = frame->data[i];
350         }
351 
352         return frame->can_dlc + 3;
353     }
354 
355     return -1;
356 }
357 
358 static int frame2buff_bas(const qemu_can_frame *frame, uint8_t *buff)
359 {
360     int i;
361 
362      /*
363       * EFF, no support for BasicMode
364       * No use for Error frames now,
365       * they could be used in future to update SJA1000 error state
366       */
367     if ((frame->can_id & QEMU_CAN_EFF_FLAG) ||
368        (frame->can_id & QEMU_CAN_ERR_FLAG)) {
369         return -1;
370     }
371 
372     buff[0] = extract32(frame->can_id, 3, 8); /* ID.10~ID.03 */
373     buff[1] = extract32(frame->can_id, 0, 3) << 5; /* ID.02~ID.00,xxxxx */
374     if (frame->can_id & QEMU_CAN_RTR_FLAG) { /* RTR */
375         buff[1] |= (1 << 4);
376     }
377     buff[1] |= frame->can_dlc & 0x0f;
378     for (i = 0; i < frame->can_dlc; i++) {
379         buff[2 + i] = frame->data[i];
380     }
381 
382     return frame->can_dlc + 2;
383 }
384 
385 static void can_sja_update_pel_irq(CanSJA1000State *s)
386 {
387     if (s->interrupt_en & s->interrupt_pel) {
388         qemu_irq_raise(s->irq);
389     } else {
390         qemu_irq_lower(s->irq);
391     }
392 }
393 
394 static void can_sja_update_bas_irq(CanSJA1000State *s)
395 {
396     if ((s->control >> 1) & s->interrupt_bas) {
397         qemu_irq_raise(s->irq);
398     } else {
399         qemu_irq_lower(s->irq);
400     }
401 }
402 
403 void can_sja_mem_write(CanSJA1000State *s, hwaddr addr, uint64_t val,
404                        unsigned size)
405 {
406     qemu_can_frame   frame;
407     uint32_t         tmp;
408     uint8_t          tmp8, count;
409 
410 
411     DPRINTF("write 0x%02llx addr 0x%02x\n",
412             (unsigned long long)val, (unsigned int)addr);
413 
414     if (addr > CAN_SJA_MEM_SIZE) {
415         return ;
416     }
417 
418     if (s->clock & 0x80) { /* PeliCAN Mode */
419         switch (addr) {
420         case SJA_MOD: /* Mode register */
421             s->mode = 0x1f & val;
422             if ((s->mode & 0x01) && ((val & 0x01) == 0)) {
423                 /* Go to operation mode from reset mode. */
424                 if (s->mode & (1 << 3)) { /* Single mode. */
425                     /* For EFF */
426                     can_sja_single_filter(&s->filter[0],
427                         s->code_mask + 0, s->code_mask + 4, 1);
428 
429                     /* For SFF */
430                     can_sja_single_filter(&s->filter[1],
431                         s->code_mask + 0, s->code_mask + 4, 0);
432 
433                     can_bus_client_set_filters(&s->bus_client, s->filter, 2);
434                 } else { /* Dual mode */
435                     /* For EFF */
436                     can_sja_dual_filter(&s->filter[0],
437                         s->code_mask + 0, s->code_mask + 4, 1);
438 
439                     can_sja_dual_filter(&s->filter[1],
440                         s->code_mask + 2, s->code_mask + 6, 1);
441 
442                     /* For SFF */
443                     can_sja_dual_filter(&s->filter[2],
444                         s->code_mask + 0, s->code_mask + 4, 0);
445 
446                     can_sja_dual_filter(&s->filter[3],
447                         s->code_mask + 2, s->code_mask + 6, 0);
448 
449                     can_bus_client_set_filters(&s->bus_client, s->filter, 4);
450                 }
451 
452                 s->rxmsg_cnt = 0;
453                 s->rx_cnt = 0;
454             }
455             break;
456 
457         case SJA_CMR: /* Command register. */
458             if (0x01 & val) { /* Send transmission request. */
459                 buff2frame_pel(s->tx_buff, &frame);
460                 if (DEBUG_FILTER) {
461                     can_display_msg("[cansja]: Tx request " , &frame);
462                 }
463 
464                 /*
465                  * Clear transmission complete status,
466                  * and Transmit Buffer Status.
467                  * write to the backends.
468                  */
469                 s->status_pel &= ~(3 << 2);
470 
471                 can_bus_client_send(&s->bus_client, &frame, 1);
472 
473                 /*
474                  * Set transmission complete status
475                  * and Transmit Buffer Status.
476                  */
477                 s->status_pel |= (3 << 2);
478 
479                 /* Clear transmit status. */
480                 s->status_pel &= ~(1 << 5);
481                 s->interrupt_pel |= 0x02;
482                 can_sja_update_pel_irq(s);
483             }
484             if (0x04 & val) { /* Release Receive Buffer */
485                 if (s->rxmsg_cnt <= 0) {
486                     break;
487                 }
488 
489                 tmp8 = s->rx_buff[s->rxbuf_start]; count = 0;
490                 if (tmp8 & (1 << 7)) { /* EFF */
491                     count += 2;
492                 }
493                 count += 3;
494                 if (!(tmp8 & (1 << 6))) { /* DATA */
495                     count += (tmp8 & 0x0f);
496                 }
497 
498                 if (DEBUG_FILTER) {
499                     qemu_log("[cansja]: message released from "
500                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
501                 }
502 
503                 s->rxbuf_start += count;
504                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
505 
506                 s->rx_cnt -= count;
507                 s->rxmsg_cnt--;
508                 if (s->rxmsg_cnt == 0) {
509                     s->status_pel &= ~(1 << 0);
510                     s->interrupt_pel &= ~(1 << 0);
511                     can_sja_update_pel_irq(s);
512                 }
513             }
514             if (0x08 & val) { /* Clear data overrun */
515                 s->status_pel &= ~(1 << 1);
516                 s->interrupt_pel &= ~(1 << 3);
517                 can_sja_update_pel_irq(s);
518             }
519             break;
520         case SJA_SR: /* Status register */
521         case SJA_IR: /* Interrupt register */
522             break; /* Do nothing */
523         case SJA_IER: /* Interrupt enable register */
524             s->interrupt_en = val;
525             break;
526         case 16: /* RX frame information addr16-28. */
527             s->status_pel |= (1 << 5); /* Set transmit status. */
528             /* fallthrough */
529         case 17 ... 28:
530             if (s->mode & 0x01) { /* Reset mode */
531                 if (addr < 24) {
532                     s->code_mask[addr - 16] = val;
533                 }
534             } else { /* Operation mode */
535                 s->tx_buff[addr - 16] = val; /* Store to TX buffer directly. */
536             }
537             break;
538         case SJA_CDR:
539             s->clock = val;
540             break;
541         }
542     } else { /* Basic Mode */
543         switch (addr) {
544         case SJA_BCAN_CTR: /* Control register, addr 0 */
545             if ((s->control & 0x01) && ((val & 0x01) == 0)) {
546                 /* Go to operation mode from reset mode. */
547                 s->filter[0].can_id = (s->code << 3) & (0xff << 3);
548                 tmp = (~(s->mask << 3)) & (0xff << 3);
549                 tmp |= QEMU_CAN_EFF_FLAG; /* Only Basic CAN Frame. */
550                 s->filter[0].can_mask = tmp;
551                 can_bus_client_set_filters(&s->bus_client, s->filter, 1);
552 
553                 s->rxmsg_cnt = 0;
554                 s->rx_cnt = 0;
555             } else if (!(s->control & 0x01) && !(val & 0x01)) {
556                 can_sja_software_reset(s);
557             }
558 
559             s->control = 0x1f & val;
560             break;
561         case SJA_BCAN_CMR: /* Command register, addr 1 */
562             if (0x01 & val) { /* Send transmission request. */
563                 buff2frame_bas(s->tx_buff, &frame);
564                 if (DEBUG_FILTER) {
565                     can_display_msg("[cansja]: Tx request " , &frame);
566                 }
567 
568                 /*
569                  * Clear transmission complete status,
570                  * and Transmit Buffer Status.
571                  */
572                 s->status_bas &= ~(3 << 2);
573 
574                 /* write to the backends. */
575                 can_bus_client_send(&s->bus_client, &frame, 1);
576 
577                 /*
578                  * Set transmission complete status,
579                  * and Transmit Buffer Status.
580                  */
581                 s->status_bas |= (3 << 2);
582 
583                 /* Clear transmit status. */
584                 s->status_bas &= ~(1 << 5);
585                 s->interrupt_bas |= 0x02;
586                 can_sja_update_bas_irq(s);
587             }
588             if (0x04 & val) { /* Release Receive Buffer */
589                 if (s->rxmsg_cnt <= 0) {
590                     break;
591                 }
592 
593                 tmp8 = s->rx_buff[(s->rxbuf_start + 1) % SJA_RCV_BUF_LEN];
594                 count = 2 + (tmp8 & 0x0f);
595 
596                 if (DEBUG_FILTER) {
597                     qemu_log("[cansja]: message released from "
598                              "Rx FIFO cnt=%d, count=%d\n", s->rx_cnt, count);
599                 }
600 
601                 s->rxbuf_start += count;
602                 s->rxbuf_start %= SJA_RCV_BUF_LEN;
603                 s->rx_cnt -= count;
604                 s->rxmsg_cnt--;
605 
606                 if (s->rxmsg_cnt == 0) {
607                     s->status_bas &= ~(1 << 0);
608                     s->interrupt_bas &= ~(1 << 0);
609                     can_sja_update_bas_irq(s);
610                 }
611             }
612             if (0x08 & val) { /* Clear data overrun */
613                 s->status_bas &= ~(1 << 1);
614                 s->interrupt_bas &= ~(1 << 3);
615                 can_sja_update_bas_irq(s);
616             }
617             break;
618         case 4:
619             s->code = val;
620             break;
621         case 5:
622             s->mask = val;
623             break;
624         case 10:
625             s->status_bas |= (1 << 5); /* Set transmit status. */
626             /* fallthrough */
627         case 11 ... 19:
628             if ((s->control & 0x01) == 0) { /* Operation mode */
629                 s->tx_buff[addr - 10] = val; /* Store to TX buffer directly. */
630             }
631             break;
632         case SJA_CDR:
633             s->clock = val;
634             break;
635         }
636     }
637 }
638 
639 uint64_t can_sja_mem_read(CanSJA1000State *s, hwaddr addr, unsigned size)
640 {
641     uint64_t temp = 0;
642 
643     DPRINTF("read addr 0x%02x ...\n", (unsigned int)addr);
644 
645     if (addr > CAN_SJA_MEM_SIZE) {
646         return 0;
647     }
648 
649     if (s->clock & 0x80) { /* PeliCAN Mode */
650         switch (addr) {
651         case SJA_MOD: /* Mode register, addr 0 */
652             temp = s->mode;
653             break;
654         case SJA_CMR: /* Command register, addr 1 */
655             temp = 0x00; /* Command register, cannot be read. */
656             break;
657         case SJA_SR: /* Status register, addr 2 */
658             temp = s->status_pel;
659             break;
660         case SJA_IR: /* Interrupt register, addr 3 */
661             temp = s->interrupt_pel;
662             s->interrupt_pel = 0;
663             if (s->rxmsg_cnt) {
664                 s->interrupt_pel |= (1 << 0); /* Receive interrupt. */
665             }
666             can_sja_update_pel_irq(s);
667             break;
668         case SJA_IER: /* Interrupt enable register, addr 4 */
669             temp = s->interrupt_en;
670             break;
671         case 5: /* Reserved */
672         case 6: /* Bus timing 0, hardware related, not support now. */
673         case 7: /* Bus timing 1, hardware related, not support now. */
674         case 8: /*
675                  * Output control register, hardware related,
676                  * not supported for now.
677                  */
678         case 9: /* Test. */
679         case 10 ... 15: /* Reserved */
680             temp = 0x00;
681             break;
682 
683         case 16 ... 28:
684             if (s->mode & 0x01) { /* Reset mode */
685                 if (addr < 24) {
686                     temp = s->code_mask[addr - 16];
687                 } else {
688                     temp = 0x00;
689                 }
690             } else { /* Operation mode */
691                 temp = s->rx_buff[(s->rxbuf_start + addr - 16) %
692                        SJA_RCV_BUF_LEN];
693             }
694             break;
695         case SJA_CDR:
696             temp = s->clock;
697             break;
698         default:
699             temp = 0xff;
700         }
701     } else { /* Basic Mode */
702         switch (addr) {
703         case SJA_BCAN_CTR: /* Control register, addr 0 */
704             temp = s->control;
705             break;
706         case SJA_BCAN_SR: /* Status register, addr 2 */
707             temp = s->status_bas;
708             break;
709         case SJA_BCAN_IR: /* Interrupt register, addr 3 */
710             temp = s->interrupt_bas;
711             s->interrupt_bas = 0;
712             if (s->rxmsg_cnt) {
713                 s->interrupt_bas |= (1 << 0); /* Receive interrupt. */
714             }
715             can_sja_update_bas_irq(s);
716             break;
717         case 4:
718             temp = s->code;
719             break;
720         case 5:
721             temp = s->mask;
722             break;
723         case 20 ... 29:
724             temp = s->rx_buff[(s->rxbuf_start + addr - 20) % SJA_RCV_BUF_LEN];
725             break;
726         case 31:
727             temp = s->clock;
728             break;
729         default:
730             temp = 0xff;
731             break;
732         }
733     }
734     DPRINTF("read addr 0x%02x, %d bytes, content 0x%02lx\n",
735             (int)addr, size, (long unsigned int)temp);
736 
737     return temp;
738 }
739 
740 bool can_sja_can_receive(CanBusClientState *client)
741 {
742     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
743 
744     if (s->clock & 0x80) { /* PeliCAN Mode */
745         if (s->mode & 0x01) { /* reset mode. */
746             return false;
747         }
748     } else { /* BasicCAN mode */
749         if (s->control & 0x01) {
750             return false;
751         }
752     }
753 
754     return true; /* always return true, when operation mode */
755 }
756 
757 ssize_t can_sja_receive(CanBusClientState *client, const qemu_can_frame *frames,
758                         size_t frames_cnt)
759 {
760     CanSJA1000State *s = container_of(client, CanSJA1000State, bus_client);
761     static uint8_t rcv[SJA_MSG_MAX_LEN];
762     int i;
763     int ret = -1;
764     const qemu_can_frame *frame = frames;
765 
766     if (frames_cnt <= 0) {
767         return 0;
768     }
769     if (DEBUG_FILTER) {
770         can_display_msg("[cansja]: receive ", frame);
771     }
772 
773     if (s->clock & 0x80) { /* PeliCAN Mode */
774 
775         /* the CAN controller is receiving a message */
776         s->status_pel |= (1 << 4);
777 
778         if (can_sja_accept_filter(s, frame) == 0) {
779             s->status_pel &= ~(1 << 4);
780             if (DEBUG_FILTER) {
781                 qemu_log("[cansja]: filter rejects message\n");
782             }
783             return ret;
784         }
785 
786         ret = frame2buff_pel(frame, rcv);
787         if (ret < 0) {
788             s->status_pel &= ~(1 << 4);
789             if (DEBUG_FILTER) {
790                 qemu_log("[cansja]: message store failed\n");
791             }
792             return ret; /* maybe not support now. */
793         }
794 
795         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
796             s->status_pel |= (1 << 1); /* Overrun status */
797             s->interrupt_pel |= (1 << 3);
798             s->status_pel &= ~(1 << 4);
799             if (DEBUG_FILTER) {
800                 qemu_log("[cansja]: receive FIFO overrun\n");
801             }
802             can_sja_update_pel_irq(s);
803             return ret;
804         }
805         s->rx_cnt += ret;
806         s->rxmsg_cnt++;
807         if (DEBUG_FILTER) {
808             qemu_log("[cansja]: message stored in receive FIFO\n");
809         }
810 
811         for (i = 0; i < ret; i++) {
812             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
813         }
814         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
815 
816         s->status_pel |= 0x01; /* Set the Receive Buffer Status. DS-p23 */
817         s->interrupt_pel |= 0x01;
818         s->status_pel &= ~(1 << 4);
819         s->status_pel |= (1 << 0);
820         can_sja_update_pel_irq(s);
821     } else { /* BasicCAN mode */
822 
823         /* the CAN controller is receiving a message */
824         s->status_bas |= (1 << 4);
825 
826         ret = frame2buff_bas(frame, rcv);
827         if (ret < 0) {
828             s->status_bas &= ~(1 << 4);
829             if (DEBUG_FILTER) {
830                 qemu_log("[cansja]: message store failed\n");
831             }
832             return ret; /* maybe not support now. */
833         }
834 
835         if (s->rx_cnt + ret > SJA_RCV_BUF_LEN) { /* Data overrun. */
836             s->status_bas |= (1 << 1); /* Overrun status */
837             s->status_bas &= ~(1 << 4);
838             s->interrupt_bas |= (1 << 3);
839             can_sja_update_bas_irq(s);
840             if (DEBUG_FILTER) {
841                 qemu_log("[cansja]: receive FIFO overrun\n");
842             }
843             return ret;
844         }
845         s->rx_cnt += ret;
846         s->rxmsg_cnt++;
847 
848         if (DEBUG_FILTER) {
849             qemu_log("[cansja]: message stored\n");
850         }
851 
852         for (i = 0; i < ret; i++) {
853             s->rx_buff[(s->rx_ptr++) % SJA_RCV_BUF_LEN] = rcv[i];
854         }
855         s->rx_ptr %= SJA_RCV_BUF_LEN; /* update the pointer. */
856 
857         s->status_bas |= 0x01; /* Set the Receive Buffer Status. DS-p15 */
858         s->status_bas &= ~(1 << 4);
859         s->interrupt_bas |= (1 << 0);
860         can_sja_update_bas_irq(s);
861     }
862     return 1;
863 }
864 
865 static CanBusClientInfo can_sja_bus_client_info = {
866     .can_receive = can_sja_can_receive,
867     .receive = can_sja_receive,
868 };
869 
870 
871 int can_sja_connect_to_bus(CanSJA1000State *s, CanBusState *bus)
872 {
873     s->bus_client.info = &can_sja_bus_client_info;
874 
875     if (!bus) {
876         return -EINVAL;
877     }
878 
879     if (can_bus_insert_client(bus, &s->bus_client) < 0) {
880         return -1;
881     }
882 
883     return 0;
884 }
885 
886 void can_sja_disconnect(CanSJA1000State *s)
887 {
888     can_bus_remove_client(&s->bus_client);
889 }
890 
891 int can_sja_init(CanSJA1000State *s, qemu_irq irq)
892 {
893     s->irq = irq;
894 
895     qemu_irq_lower(s->irq);
896 
897     can_sja_hardware_reset(s);
898 
899     return 0;
900 }
901 
902 const VMStateDescription vmstate_qemu_can_filter = {
903     .name = "qemu_can_filter",
904     .version_id = 1,
905     .minimum_version_id = 1,
906     .minimum_version_id_old = 1,
907     .fields = (VMStateField[]) {
908         VMSTATE_UINT32(can_id, qemu_can_filter),
909         VMSTATE_UINT32(can_mask, qemu_can_filter),
910         VMSTATE_END_OF_LIST()
911     }
912 };
913 
914 static int can_sja_post_load(void *opaque, int version_id)
915 {
916     CanSJA1000State *s = opaque;
917     if (s->clock & 0x80) { /* PeliCAN Mode */
918         can_sja_update_pel_irq(s);
919     } else {
920         can_sja_update_bas_irq(s);
921     }
922     return 0;
923 }
924 
925 /* VMState is needed for live migration of QEMU images */
926 const VMStateDescription vmstate_can_sja = {
927     .name = "can_sja",
928     .version_id = 1,
929     .minimum_version_id = 1,
930     .minimum_version_id_old = 1,
931     .post_load = can_sja_post_load,
932     .fields = (VMStateField[]) {
933         VMSTATE_UINT8(mode, CanSJA1000State),
934 
935         VMSTATE_UINT8(status_pel, CanSJA1000State),
936         VMSTATE_UINT8(interrupt_pel, CanSJA1000State),
937         VMSTATE_UINT8(interrupt_en, CanSJA1000State),
938         VMSTATE_UINT8(rxmsg_cnt, CanSJA1000State),
939         VMSTATE_UINT8(rxbuf_start, CanSJA1000State),
940         VMSTATE_UINT8(clock, CanSJA1000State),
941 
942         VMSTATE_BUFFER(code_mask, CanSJA1000State),
943         VMSTATE_BUFFER(tx_buff, CanSJA1000State),
944 
945         VMSTATE_BUFFER(rx_buff, CanSJA1000State),
946 
947         VMSTATE_UINT32(rx_ptr, CanSJA1000State),
948         VMSTATE_UINT32(rx_cnt, CanSJA1000State),
949 
950         VMSTATE_UINT8(control, CanSJA1000State),
951 
952         VMSTATE_UINT8(status_bas, CanSJA1000State),
953         VMSTATE_UINT8(interrupt_bas, CanSJA1000State),
954         VMSTATE_UINT8(code, CanSJA1000State),
955         VMSTATE_UINT8(mask, CanSJA1000State),
956 
957         VMSTATE_STRUCT_ARRAY(filter, CanSJA1000State, 4, 0,
958                              vmstate_qemu_can_filter, qemu_can_filter),
959 
960 
961         VMSTATE_END_OF_LIST()
962     }
963 };
964