xref: /openbmc/qemu/hw/char/ipoctal232.c (revision e4370165)
1 /*
2  * QEMU GE IP-Octal 232 IndustryPack emulation
3  *
4  * Copyright (C) 2012 Igalia, S.L.
5  * Author: Alberto Garcia <berto@igalia.com>
6  *
7  * This code is licensed under the GNU GPL v2 or (at your option) any
8  * later version.
9  */
10 
11 #include "qemu/osdep.h"
12 #include "hw/ipack/ipack.h"
13 #include "qemu/bitops.h"
14 #include "sysemu/char.h"
15 
16 /* #define DEBUG_IPOCTAL */
17 
18 #ifdef DEBUG_IPOCTAL
19 #define DPRINTF2(fmt, ...) \
20     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
21 #else
22 #define DPRINTF2(fmt, ...) do { } while (0)
23 #endif
24 
25 #define DPRINTF(fmt, ...) DPRINTF2("IP-Octal: " fmt, ## __VA_ARGS__)
26 
27 #define RX_FIFO_SIZE 3
28 
29 /* The IP-Octal has 8 channels (a-h)
30    divided into 4 blocks (A-D) */
31 #define N_CHANNELS 8
32 #define N_BLOCKS   4
33 
34 #define REG_MRa  0x01
35 #define REG_MRb  0x11
36 #define REG_SRa  0x03
37 #define REG_SRb  0x13
38 #define REG_CSRa 0x03
39 #define REG_CSRb 0x13
40 #define REG_CRa  0x05
41 #define REG_CRb  0x15
42 #define REG_RHRa 0x07
43 #define REG_RHRb 0x17
44 #define REG_THRa 0x07
45 #define REG_THRb 0x17
46 #define REG_ACR  0x09
47 #define REG_ISR  0x0B
48 #define REG_IMR  0x0B
49 #define REG_OPCR 0x1B
50 
51 #define CR_ENABLE_RX    BIT(0)
52 #define CR_DISABLE_RX   BIT(1)
53 #define CR_ENABLE_TX    BIT(2)
54 #define CR_DISABLE_TX   BIT(3)
55 #define CR_CMD(cr)      ((cr) >> 4)
56 #define CR_NO_OP        0
57 #define CR_RESET_MR     1
58 #define CR_RESET_RX     2
59 #define CR_RESET_TX     3
60 #define CR_RESET_ERR    4
61 #define CR_RESET_BRKINT 5
62 #define CR_START_BRK    6
63 #define CR_STOP_BRK     7
64 #define CR_ASSERT_RTSN  8
65 #define CR_NEGATE_RTSN  9
66 #define CR_TIMEOUT_ON   10
67 #define CR_TIMEOUT_OFF  12
68 
69 #define SR_RXRDY   BIT(0)
70 #define SR_FFULL   BIT(1)
71 #define SR_TXRDY   BIT(2)
72 #define SR_TXEMT   BIT(3)
73 #define SR_OVERRUN BIT(4)
74 #define SR_PARITY  BIT(5)
75 #define SR_FRAMING BIT(6)
76 #define SR_BREAK   BIT(7)
77 
78 #define ISR_TXRDYA BIT(0)
79 #define ISR_RXRDYA BIT(1)
80 #define ISR_BREAKA BIT(2)
81 #define ISR_CNTRDY BIT(3)
82 #define ISR_TXRDYB BIT(4)
83 #define ISR_RXRDYB BIT(5)
84 #define ISR_BREAKB BIT(6)
85 #define ISR_MPICHG BIT(7)
86 #define ISR_TXRDY(CH) (((CH) & 1) ? BIT(4) : BIT(0))
87 #define ISR_RXRDY(CH) (((CH) & 1) ? BIT(5) : BIT(1))
88 #define ISR_BREAK(CH) (((CH) & 1) ? BIT(6) : BIT(2))
89 
90 typedef struct IPOctalState IPOctalState;
91 typedef struct SCC2698Channel SCC2698Channel;
92 typedef struct SCC2698Block SCC2698Block;
93 
94 struct SCC2698Channel {
95     IPOctalState *ipoctal;
96     CharBackend dev;
97     bool rx_enabled;
98     uint8_t mr[2];
99     uint8_t mr_idx;
100     uint8_t sr;
101     uint8_t rhr[RX_FIFO_SIZE];
102     uint8_t rhr_idx;
103     uint8_t rx_pending;
104 };
105 
106 struct SCC2698Block {
107     uint8_t imr;
108     uint8_t isr;
109 };
110 
111 struct IPOctalState {
112     IPackDevice parent_obj;
113 
114     SCC2698Channel ch[N_CHANNELS];
115     SCC2698Block blk[N_BLOCKS];
116     uint8_t irq_vector;
117 };
118 
119 #define TYPE_IPOCTAL "ipoctal232"
120 
121 #define IPOCTAL(obj) \
122     OBJECT_CHECK(IPOctalState, (obj), TYPE_IPOCTAL)
123 
124 static const VMStateDescription vmstate_scc2698_channel = {
125     .name = "scc2698_channel",
126     .version_id = 1,
127     .minimum_version_id = 1,
128     .fields = (VMStateField[]) {
129         VMSTATE_BOOL(rx_enabled, SCC2698Channel),
130         VMSTATE_UINT8_ARRAY(mr, SCC2698Channel, 2),
131         VMSTATE_UINT8(mr_idx, SCC2698Channel),
132         VMSTATE_UINT8(sr, SCC2698Channel),
133         VMSTATE_UINT8_ARRAY(rhr, SCC2698Channel, RX_FIFO_SIZE),
134         VMSTATE_UINT8(rhr_idx, SCC2698Channel),
135         VMSTATE_UINT8(rx_pending, SCC2698Channel),
136         VMSTATE_END_OF_LIST()
137     }
138 };
139 
140 static const VMStateDescription vmstate_scc2698_block = {
141     .name = "scc2698_block",
142     .version_id = 1,
143     .minimum_version_id = 1,
144     .fields = (VMStateField[]) {
145         VMSTATE_UINT8(imr, SCC2698Block),
146         VMSTATE_UINT8(isr, SCC2698Block),
147         VMSTATE_END_OF_LIST()
148     }
149 };
150 
151 static const VMStateDescription vmstate_ipoctal = {
152     .name = "ipoctal232",
153     .version_id = 1,
154     .minimum_version_id = 1,
155     .fields = (VMStateField[]) {
156         VMSTATE_IPACK_DEVICE(parent_obj, IPOctalState),
157         VMSTATE_STRUCT_ARRAY(ch, IPOctalState, N_CHANNELS, 1,
158                              vmstate_scc2698_channel, SCC2698Channel),
159         VMSTATE_STRUCT_ARRAY(blk, IPOctalState, N_BLOCKS, 1,
160                              vmstate_scc2698_block, SCC2698Block),
161         VMSTATE_UINT8(irq_vector, IPOctalState),
162         VMSTATE_END_OF_LIST()
163     }
164 };
165 
166 /* data[10] is 0x0C, not 0x0B as the doc says */
167 static const uint8_t id_prom_data[] = {
168     0x49, 0x50, 0x41, 0x43, 0xF0, 0x22,
169     0xA1, 0x00, 0x00, 0x00, 0x0C, 0xCC
170 };
171 
172 static void update_irq(IPOctalState *dev, unsigned block)
173 {
174     IPackDevice *idev = IPACK_DEVICE(dev);
175     /* Blocks A and B interrupt on INT0#, C and D on INT1#.
176        Thus, to get the status we have to check two blocks. */
177     SCC2698Block *blk0 = &dev->blk[block];
178     SCC2698Block *blk1 = &dev->blk[block^1];
179     unsigned intno = block / 2;
180 
181     if ((blk0->isr & blk0->imr) || (blk1->isr & blk1->imr)) {
182         qemu_irq_raise(idev->irq[intno]);
183     } else {
184         qemu_irq_lower(idev->irq[intno]);
185     }
186 }
187 
188 static void write_cr(IPOctalState *dev, unsigned channel, uint8_t val)
189 {
190     SCC2698Channel *ch = &dev->ch[channel];
191     SCC2698Block *blk = &dev->blk[channel / 2];
192 
193     DPRINTF("Write CR%c %u: ", channel + 'a', val);
194 
195     /* The lower 4 bits are used to enable and disable Tx and Rx */
196     if (val & CR_ENABLE_RX) {
197         DPRINTF2("Rx on, ");
198         ch->rx_enabled = true;
199     }
200     if (val & CR_DISABLE_RX) {
201         DPRINTF2("Rx off, ");
202         ch->rx_enabled = false;
203     }
204     if (val & CR_ENABLE_TX) {
205         DPRINTF2("Tx on, ");
206         ch->sr |= SR_TXRDY | SR_TXEMT;
207         blk->isr |= ISR_TXRDY(channel);
208     }
209     if (val & CR_DISABLE_TX) {
210         DPRINTF2("Tx off, ");
211         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
212         blk->isr &= ~ISR_TXRDY(channel);
213     }
214 
215     DPRINTF2("cmd: ");
216 
217     /* The rest of the bits implement different commands */
218     switch (CR_CMD(val)) {
219     case CR_NO_OP:
220         DPRINTF2("none");
221         break;
222     case CR_RESET_MR:
223         DPRINTF2("reset MR");
224         ch->mr_idx = 0;
225         break;
226     case CR_RESET_RX:
227         DPRINTF2("reset Rx");
228         ch->rx_enabled = false;
229         ch->rx_pending = 0;
230         ch->sr &= ~SR_RXRDY;
231         blk->isr &= ~ISR_RXRDY(channel);
232         break;
233     case CR_RESET_TX:
234         DPRINTF2("reset Tx");
235         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
236         blk->isr &= ~ISR_TXRDY(channel);
237         break;
238     case CR_RESET_ERR:
239         DPRINTF2("reset err");
240         ch->sr &= ~(SR_OVERRUN | SR_PARITY | SR_FRAMING | SR_BREAK);
241         break;
242     case CR_RESET_BRKINT:
243         DPRINTF2("reset brk ch int");
244         blk->isr &= ~(ISR_BREAKA | ISR_BREAKB);
245         break;
246     default:
247         DPRINTF2("unsupported 0x%x", CR_CMD(val));
248     }
249 
250     DPRINTF2("\n");
251 }
252 
253 static uint16_t io_read(IPackDevice *ip, uint8_t addr)
254 {
255     IPOctalState *dev = IPOCTAL(ip);
256     uint16_t ret = 0;
257     /* addr[7:6]: block   (A-D)
258        addr[7:5]: channel (a-h)
259        addr[5:0]: register */
260     unsigned block = addr >> 5;
261     unsigned channel = addr >> 4;
262     /* Big endian, accessed using 8-bit bytes at odd locations */
263     unsigned offset = (addr & 0x1F) ^ 1;
264     SCC2698Channel *ch = &dev->ch[channel];
265     SCC2698Block *blk = &dev->blk[block];
266     uint8_t old_isr = blk->isr;
267 
268     switch (offset) {
269 
270     case REG_MRa:
271     case REG_MRb:
272         ret = ch->mr[ch->mr_idx];
273         DPRINTF("Read MR%u%c: 0x%x\n", ch->mr_idx + 1, channel + 'a', ret);
274         ch->mr_idx = 1;
275         break;
276 
277     case REG_SRa:
278     case REG_SRb:
279         ret = ch->sr;
280         DPRINTF("Read SR%c: 0x%x\n", channel + 'a', ret);
281         break;
282 
283     case REG_RHRa:
284     case REG_RHRb:
285         ret = ch->rhr[ch->rhr_idx];
286         if (ch->rx_pending > 0) {
287             ch->rx_pending--;
288             if (ch->rx_pending == 0) {
289                 ch->sr &= ~SR_RXRDY;
290                 blk->isr &= ~ISR_RXRDY(channel);
291                 qemu_chr_fe_accept_input(&ch->dev);
292             } else {
293                 ch->rhr_idx = (ch->rhr_idx + 1) % RX_FIFO_SIZE;
294             }
295             if (ch->sr & SR_BREAK) {
296                 ch->sr &= ~SR_BREAK;
297                 blk->isr |= ISR_BREAK(channel);
298             }
299         }
300         DPRINTF("Read RHR%c (0x%x)\n", channel + 'a', ret);
301         break;
302 
303     case REG_ISR:
304         ret = blk->isr;
305         DPRINTF("Read ISR%c: 0x%x\n", block + 'A', ret);
306         break;
307 
308     default:
309         DPRINTF("Read unknown/unsupported register 0x%02x\n", offset);
310     }
311 
312     if (old_isr != blk->isr) {
313         update_irq(dev, block);
314     }
315 
316     return ret;
317 }
318 
319 static void io_write(IPackDevice *ip, uint8_t addr, uint16_t val)
320 {
321     IPOctalState *dev = IPOCTAL(ip);
322     unsigned reg = val & 0xFF;
323     /* addr[7:6]: block   (A-D)
324        addr[7:5]: channel (a-h)
325        addr[5:0]: register */
326     unsigned block = addr >> 5;
327     unsigned channel = addr >> 4;
328     /* Big endian, accessed using 8-bit bytes at odd locations */
329     unsigned offset = (addr & 0x1F) ^ 1;
330     SCC2698Channel *ch = &dev->ch[channel];
331     SCC2698Block *blk = &dev->blk[block];
332     uint8_t old_isr = blk->isr;
333     uint8_t old_imr = blk->imr;
334 
335     switch (offset) {
336 
337     case REG_MRa:
338     case REG_MRb:
339         ch->mr[ch->mr_idx] = reg;
340         DPRINTF("Write MR%u%c 0x%x\n", ch->mr_idx + 1, channel + 'a', reg);
341         ch->mr_idx = 1;
342         break;
343 
344     /* Not implemented */
345     case REG_CSRa:
346     case REG_CSRb:
347         DPRINTF("Write CSR%c: 0x%x\n", channel + 'a', reg);
348         break;
349 
350     case REG_CRa:
351     case REG_CRb:
352         write_cr(dev, channel, reg);
353         break;
354 
355     case REG_THRa:
356     case REG_THRb:
357         if (ch->sr & SR_TXRDY) {
358             uint8_t thr = reg;
359             DPRINTF("Write THR%c (0x%x)\n", channel + 'a', reg);
360             /* XXX this blocks entire thread. Rewrite to use
361              * qemu_chr_fe_write and background I/O callbacks */
362             qemu_chr_fe_write_all(&ch->dev, &thr, 1);
363         } else {
364             DPRINTF("Write THR%c (0x%x), Tx disabled\n", channel + 'a', reg);
365         }
366         break;
367 
368     /* Not implemented */
369     case REG_ACR:
370         DPRINTF("Write ACR%c 0x%x\n", block + 'A', val);
371         break;
372 
373     case REG_IMR:
374         DPRINTF("Write IMR%c 0x%x\n", block + 'A', val);
375         blk->imr = reg;
376         break;
377 
378     /* Not implemented */
379     case REG_OPCR:
380         DPRINTF("Write OPCR%c 0x%x\n", block + 'A', val);
381         break;
382 
383     default:
384         DPRINTF("Write unknown/unsupported register 0x%02x %u\n", offset, val);
385     }
386 
387     if (old_isr != blk->isr || old_imr != blk->imr) {
388         update_irq(dev, block);
389     }
390 }
391 
392 static uint16_t id_read(IPackDevice *ip, uint8_t addr)
393 {
394     uint16_t ret = 0;
395     unsigned pos = addr / 2; /* The ID PROM data is stored every other byte */
396 
397     if (pos < ARRAY_SIZE(id_prom_data)) {
398         ret = id_prom_data[pos];
399     } else {
400         DPRINTF("Attempt to read unavailable PROM data at 0x%x\n",  addr);
401     }
402 
403     return ret;
404 }
405 
406 static void id_write(IPackDevice *ip, uint8_t addr, uint16_t val)
407 {
408     IPOctalState *dev = IPOCTAL(ip);
409     if (addr == 1) {
410         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
411         dev->irq_vector = val; /* Undocumented, but the hw works like that */
412     } else {
413         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
414     }
415 }
416 
417 static uint16_t int_read(IPackDevice *ip, uint8_t addr)
418 {
419     IPOctalState *dev = IPOCTAL(ip);
420     /* Read address 0 to ACK INT0# and address 2 to ACK INT1# */
421     if (addr != 0 && addr != 2) {
422         DPRINTF("Attempt to read from 0x%x\n", addr);
423         return 0;
424     } else {
425         /* Update interrupts if necessary */
426         update_irq(dev, addr);
427         return dev->irq_vector;
428     }
429 }
430 
431 static void int_write(IPackDevice *ip, uint8_t addr, uint16_t val)
432 {
433     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
434 }
435 
436 static uint16_t mem_read16(IPackDevice *ip, uint32_t addr)
437 {
438     DPRINTF("Attempt to read from 0x%x\n", addr);
439     return 0;
440 }
441 
442 static void mem_write16(IPackDevice *ip, uint32_t addr, uint16_t val)
443 {
444     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
445 }
446 
447 static uint8_t mem_read8(IPackDevice *ip, uint32_t addr)
448 {
449     DPRINTF("Attempt to read from 0x%x\n", addr);
450     return 0;
451 }
452 
453 static void mem_write8(IPackDevice *ip, uint32_t addr, uint8_t val)
454 {
455     IPOctalState *dev = IPOCTAL(ip);
456     if (addr == 1) {
457         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
458         dev->irq_vector = val;
459     } else {
460         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
461     }
462 }
463 
464 static int hostdev_can_receive(void *opaque)
465 {
466     SCC2698Channel *ch = opaque;
467     int available_bytes = RX_FIFO_SIZE - ch->rx_pending;
468     return ch->rx_enabled ? available_bytes : 0;
469 }
470 
471 static void hostdev_receive(void *opaque, const uint8_t *buf, int size)
472 {
473     SCC2698Channel *ch = opaque;
474     IPOctalState *dev = ch->ipoctal;
475     unsigned pos = ch->rhr_idx + ch->rx_pending;
476     int i;
477 
478     assert(size + ch->rx_pending <= RX_FIFO_SIZE);
479 
480     /* Copy data to the RxFIFO */
481     for (i = 0; i < size; i++) {
482         pos %= RX_FIFO_SIZE;
483         ch->rhr[pos++] = buf[i];
484     }
485 
486     ch->rx_pending += size;
487 
488     /* If the RxFIFO was empty raise an interrupt */
489     if (!(ch->sr & SR_RXRDY)) {
490         unsigned block, channel = 0;
491         /* Find channel number to update the ISR register */
492         while (&dev->ch[channel] != ch) {
493             channel++;
494         }
495         block = channel / 2;
496         dev->blk[block].isr |= ISR_RXRDY(channel);
497         ch->sr |= SR_RXRDY;
498         update_irq(dev, block);
499     }
500 }
501 
502 static void hostdev_event(void *opaque, int event)
503 {
504     SCC2698Channel *ch = opaque;
505     switch (event) {
506     case CHR_EVENT_OPENED:
507         DPRINTF("Device %s opened\n", ch->dev->label);
508         break;
509     case CHR_EVENT_BREAK: {
510         uint8_t zero = 0;
511         DPRINTF("Device %s received break\n", ch->dev->label);
512 
513         if (!(ch->sr & SR_BREAK)) {
514             IPOctalState *dev = ch->ipoctal;
515             unsigned block, channel = 0;
516 
517             while (&dev->ch[channel] != ch) {
518                 channel++;
519             }
520             block = channel / 2;
521 
522             ch->sr |= SR_BREAK;
523             dev->blk[block].isr |= ISR_BREAK(channel);
524         }
525 
526         /* Put a zero character in the buffer */
527         hostdev_receive(ch, &zero, 1);
528     }
529         break;
530     default:
531         DPRINTF("Device %s received event %d\n", ch->dev->label, event);
532     }
533 }
534 
535 static void ipoctal_realize(DeviceState *dev, Error **errp)
536 {
537     IPOctalState *s = IPOCTAL(dev);
538     unsigned i;
539 
540     for (i = 0; i < N_CHANNELS; i++) {
541         SCC2698Channel *ch = &s->ch[i];
542         ch->ipoctal = s;
543 
544         /* Redirect IP-Octal channels to host character devices */
545         if (qemu_chr_fe_get_driver(&ch->dev)) {
546             qemu_chr_fe_set_handlers(&ch->dev, hostdev_can_receive,
547                                      hostdev_receive, hostdev_event,
548                                      ch, NULL, true);
549             DPRINTF("Redirecting channel %u to %s\n", i, ch->dev->label);
550         } else {
551             DPRINTF("Could not redirect channel %u, no chardev set\n", i);
552         }
553     }
554 }
555 
556 static Property ipoctal_properties[] = {
557     DEFINE_PROP_CHR("chardev0", IPOctalState, ch[0].dev),
558     DEFINE_PROP_CHR("chardev1", IPOctalState, ch[1].dev),
559     DEFINE_PROP_CHR("chardev2", IPOctalState, ch[2].dev),
560     DEFINE_PROP_CHR("chardev3", IPOctalState, ch[3].dev),
561     DEFINE_PROP_CHR("chardev4", IPOctalState, ch[4].dev),
562     DEFINE_PROP_CHR("chardev5", IPOctalState, ch[5].dev),
563     DEFINE_PROP_CHR("chardev6", IPOctalState, ch[6].dev),
564     DEFINE_PROP_CHR("chardev7", IPOctalState, ch[7].dev),
565     DEFINE_PROP_END_OF_LIST(),
566 };
567 
568 static void ipoctal_class_init(ObjectClass *klass, void *data)
569 {
570     DeviceClass *dc = DEVICE_CLASS(klass);
571     IPackDeviceClass *ic = IPACK_DEVICE_CLASS(klass);
572 
573     ic->realize     = ipoctal_realize;
574     ic->io_read     = io_read;
575     ic->io_write    = io_write;
576     ic->id_read     = id_read;
577     ic->id_write    = id_write;
578     ic->int_read    = int_read;
579     ic->int_write   = int_write;
580     ic->mem_read16  = mem_read16;
581     ic->mem_write16 = mem_write16;
582     ic->mem_read8   = mem_read8;
583     ic->mem_write8  = mem_write8;
584 
585     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
586     dc->desc    = "GE IP-Octal 232 8-channel RS-232 IndustryPack";
587     dc->props   = ipoctal_properties;
588     dc->vmsd    = &vmstate_ipoctal;
589 }
590 
591 static const TypeInfo ipoctal_info = {
592     .name          = TYPE_IPOCTAL,
593     .parent        = TYPE_IPACK_DEVICE,
594     .instance_size = sizeof(IPOctalState),
595     .class_init    = ipoctal_class_init,
596 };
597 
598 static void ipoctal_register_types(void)
599 {
600     type_register_static(&ipoctal_info);
601 }
602 
603 type_init(ipoctal_register_types)
604