xref: /openbmc/qemu/hw/char/ipoctal232.c (revision 6a0acfff)
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 "hw/irq.h"
14 #include "qemu/bitops.h"
15 #include "qemu/module.h"
16 #include "chardev/char-fe.h"
17 
18 /* #define DEBUG_IPOCTAL */
19 
20 #ifdef DEBUG_IPOCTAL
21 #define DPRINTF2(fmt, ...) \
22     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
23 #else
24 #define DPRINTF2(fmt, ...) do { } while (0)
25 #endif
26 
27 #define DPRINTF(fmt, ...) DPRINTF2("IP-Octal: " fmt, ## __VA_ARGS__)
28 
29 #define RX_FIFO_SIZE 3
30 
31 /* The IP-Octal has 8 channels (a-h)
32    divided into 4 blocks (A-D) */
33 #define N_CHANNELS 8
34 #define N_BLOCKS   4
35 
36 #define REG_MRa  0x01
37 #define REG_MRb  0x11
38 #define REG_SRa  0x03
39 #define REG_SRb  0x13
40 #define REG_CSRa 0x03
41 #define REG_CSRb 0x13
42 #define REG_CRa  0x05
43 #define REG_CRb  0x15
44 #define REG_RHRa 0x07
45 #define REG_RHRb 0x17
46 #define REG_THRa 0x07
47 #define REG_THRb 0x17
48 #define REG_ACR  0x09
49 #define REG_ISR  0x0B
50 #define REG_IMR  0x0B
51 #define REG_OPCR 0x1B
52 
53 #define CR_ENABLE_RX    BIT(0)
54 #define CR_DISABLE_RX   BIT(1)
55 #define CR_ENABLE_TX    BIT(2)
56 #define CR_DISABLE_TX   BIT(3)
57 #define CR_CMD(cr)      ((cr) >> 4)
58 #define CR_NO_OP        0
59 #define CR_RESET_MR     1
60 #define CR_RESET_RX     2
61 #define CR_RESET_TX     3
62 #define CR_RESET_ERR    4
63 #define CR_RESET_BRKINT 5
64 #define CR_START_BRK    6
65 #define CR_STOP_BRK     7
66 #define CR_ASSERT_RTSN  8
67 #define CR_NEGATE_RTSN  9
68 #define CR_TIMEOUT_ON   10
69 #define CR_TIMEOUT_OFF  12
70 
71 #define SR_RXRDY   BIT(0)
72 #define SR_FFULL   BIT(1)
73 #define SR_TXRDY   BIT(2)
74 #define SR_TXEMT   BIT(3)
75 #define SR_OVERRUN BIT(4)
76 #define SR_PARITY  BIT(5)
77 #define SR_FRAMING BIT(6)
78 #define SR_BREAK   BIT(7)
79 
80 #define ISR_TXRDYA BIT(0)
81 #define ISR_RXRDYA BIT(1)
82 #define ISR_BREAKA BIT(2)
83 #define ISR_CNTRDY BIT(3)
84 #define ISR_TXRDYB BIT(4)
85 #define ISR_RXRDYB BIT(5)
86 #define ISR_BREAKB BIT(6)
87 #define ISR_MPICHG BIT(7)
88 #define ISR_TXRDY(CH) (((CH) & 1) ? BIT(4) : BIT(0))
89 #define ISR_RXRDY(CH) (((CH) & 1) ? BIT(5) : BIT(1))
90 #define ISR_BREAK(CH) (((CH) & 1) ? BIT(6) : BIT(2))
91 
92 typedef struct IPOctalState IPOctalState;
93 typedef struct SCC2698Channel SCC2698Channel;
94 typedef struct SCC2698Block SCC2698Block;
95 
96 struct SCC2698Channel {
97     IPOctalState *ipoctal;
98     CharBackend dev;
99     bool rx_enabled;
100     uint8_t mr[2];
101     uint8_t mr_idx;
102     uint8_t sr;
103     uint8_t rhr[RX_FIFO_SIZE];
104     uint8_t rhr_idx;
105     uint8_t rx_pending;
106 };
107 
108 struct SCC2698Block {
109     uint8_t imr;
110     uint8_t isr;
111 };
112 
113 struct IPOctalState {
114     IPackDevice parent_obj;
115 
116     SCC2698Channel ch[N_CHANNELS];
117     SCC2698Block blk[N_BLOCKS];
118     uint8_t irq_vector;
119 };
120 
121 #define TYPE_IPOCTAL "ipoctal232"
122 
123 #define IPOCTAL(obj) \
124     OBJECT_CHECK(IPOctalState, (obj), TYPE_IPOCTAL)
125 
126 static const VMStateDescription vmstate_scc2698_channel = {
127     .name = "scc2698_channel",
128     .version_id = 1,
129     .minimum_version_id = 1,
130     .fields = (VMStateField[]) {
131         VMSTATE_BOOL(rx_enabled, SCC2698Channel),
132         VMSTATE_UINT8_ARRAY(mr, SCC2698Channel, 2),
133         VMSTATE_UINT8(mr_idx, SCC2698Channel),
134         VMSTATE_UINT8(sr, SCC2698Channel),
135         VMSTATE_UINT8_ARRAY(rhr, SCC2698Channel, RX_FIFO_SIZE),
136         VMSTATE_UINT8(rhr_idx, SCC2698Channel),
137         VMSTATE_UINT8(rx_pending, SCC2698Channel),
138         VMSTATE_END_OF_LIST()
139     }
140 };
141 
142 static const VMStateDescription vmstate_scc2698_block = {
143     .name = "scc2698_block",
144     .version_id = 1,
145     .minimum_version_id = 1,
146     .fields = (VMStateField[]) {
147         VMSTATE_UINT8(imr, SCC2698Block),
148         VMSTATE_UINT8(isr, SCC2698Block),
149         VMSTATE_END_OF_LIST()
150     }
151 };
152 
153 static const VMStateDescription vmstate_ipoctal = {
154     .name = "ipoctal232",
155     .version_id = 1,
156     .minimum_version_id = 1,
157     .fields = (VMStateField[]) {
158         VMSTATE_IPACK_DEVICE(parent_obj, IPOctalState),
159         VMSTATE_STRUCT_ARRAY(ch, IPOctalState, N_CHANNELS, 1,
160                              vmstate_scc2698_channel, SCC2698Channel),
161         VMSTATE_STRUCT_ARRAY(blk, IPOctalState, N_BLOCKS, 1,
162                              vmstate_scc2698_block, SCC2698Block),
163         VMSTATE_UINT8(irq_vector, IPOctalState),
164         VMSTATE_END_OF_LIST()
165     }
166 };
167 
168 /* data[10] is 0x0C, not 0x0B as the doc says */
169 static const uint8_t id_prom_data[] = {
170     0x49, 0x50, 0x41, 0x43, 0xF0, 0x22,
171     0xA1, 0x00, 0x00, 0x00, 0x0C, 0xCC
172 };
173 
174 static void update_irq(IPOctalState *dev, unsigned block)
175 {
176     IPackDevice *idev = IPACK_DEVICE(dev);
177     /* Blocks A and B interrupt on INT0#, C and D on INT1#.
178        Thus, to get the status we have to check two blocks. */
179     SCC2698Block *blk0 = &dev->blk[block];
180     SCC2698Block *blk1 = &dev->blk[block^1];
181     unsigned intno = block / 2;
182 
183     if ((blk0->isr & blk0->imr) || (blk1->isr & blk1->imr)) {
184         qemu_irq_raise(idev->irq[intno]);
185     } else {
186         qemu_irq_lower(idev->irq[intno]);
187     }
188 }
189 
190 static void write_cr(IPOctalState *dev, unsigned channel, uint8_t val)
191 {
192     SCC2698Channel *ch = &dev->ch[channel];
193     SCC2698Block *blk = &dev->blk[channel / 2];
194 
195     DPRINTF("Write CR%c %u: ", channel + 'a', val);
196 
197     /* The lower 4 bits are used to enable and disable Tx and Rx */
198     if (val & CR_ENABLE_RX) {
199         DPRINTF2("Rx on, ");
200         ch->rx_enabled = true;
201     }
202     if (val & CR_DISABLE_RX) {
203         DPRINTF2("Rx off, ");
204         ch->rx_enabled = false;
205     }
206     if (val & CR_ENABLE_TX) {
207         DPRINTF2("Tx on, ");
208         ch->sr |= SR_TXRDY | SR_TXEMT;
209         blk->isr |= ISR_TXRDY(channel);
210     }
211     if (val & CR_DISABLE_TX) {
212         DPRINTF2("Tx off, ");
213         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
214         blk->isr &= ~ISR_TXRDY(channel);
215     }
216 
217     DPRINTF2("cmd: ");
218 
219     /* The rest of the bits implement different commands */
220     switch (CR_CMD(val)) {
221     case CR_NO_OP:
222         DPRINTF2("none");
223         break;
224     case CR_RESET_MR:
225         DPRINTF2("reset MR");
226         ch->mr_idx = 0;
227         break;
228     case CR_RESET_RX:
229         DPRINTF2("reset Rx");
230         ch->rx_enabled = false;
231         ch->rx_pending = 0;
232         ch->sr &= ~SR_RXRDY;
233         blk->isr &= ~ISR_RXRDY(channel);
234         break;
235     case CR_RESET_TX:
236         DPRINTF2("reset Tx");
237         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
238         blk->isr &= ~ISR_TXRDY(channel);
239         break;
240     case CR_RESET_ERR:
241         DPRINTF2("reset err");
242         ch->sr &= ~(SR_OVERRUN | SR_PARITY | SR_FRAMING | SR_BREAK);
243         break;
244     case CR_RESET_BRKINT:
245         DPRINTF2("reset brk ch int");
246         blk->isr &= ~(ISR_BREAKA | ISR_BREAKB);
247         break;
248     default:
249         DPRINTF2("unsupported 0x%x", CR_CMD(val));
250     }
251 
252     DPRINTF2("\n");
253 }
254 
255 static uint16_t io_read(IPackDevice *ip, uint8_t addr)
256 {
257     IPOctalState *dev = IPOCTAL(ip);
258     uint16_t ret = 0;
259     /* addr[7:6]: block   (A-D)
260        addr[7:5]: channel (a-h)
261        addr[5:0]: register */
262     unsigned block = addr >> 5;
263     unsigned channel = addr >> 4;
264     /* Big endian, accessed using 8-bit bytes at odd locations */
265     unsigned offset = (addr & 0x1F) ^ 1;
266     SCC2698Channel *ch = &dev->ch[channel];
267     SCC2698Block *blk = &dev->blk[block];
268     uint8_t old_isr = blk->isr;
269 
270     switch (offset) {
271 
272     case REG_MRa:
273     case REG_MRb:
274         ret = ch->mr[ch->mr_idx];
275         DPRINTF("Read MR%u%c: 0x%x\n", ch->mr_idx + 1, channel + 'a', ret);
276         ch->mr_idx = 1;
277         break;
278 
279     case REG_SRa:
280     case REG_SRb:
281         ret = ch->sr;
282         DPRINTF("Read SR%c: 0x%x\n", channel + 'a', ret);
283         break;
284 
285     case REG_RHRa:
286     case REG_RHRb:
287         ret = ch->rhr[ch->rhr_idx];
288         if (ch->rx_pending > 0) {
289             ch->rx_pending--;
290             if (ch->rx_pending == 0) {
291                 ch->sr &= ~SR_RXRDY;
292                 blk->isr &= ~ISR_RXRDY(channel);
293                 qemu_chr_fe_accept_input(&ch->dev);
294             } else {
295                 ch->rhr_idx = (ch->rhr_idx + 1) % RX_FIFO_SIZE;
296             }
297             if (ch->sr & SR_BREAK) {
298                 ch->sr &= ~SR_BREAK;
299                 blk->isr |= ISR_BREAK(channel);
300             }
301         }
302         DPRINTF("Read RHR%c (0x%x)\n", channel + 'a', ret);
303         break;
304 
305     case REG_ISR:
306         ret = blk->isr;
307         DPRINTF("Read ISR%c: 0x%x\n", block + 'A', ret);
308         break;
309 
310     default:
311         DPRINTF("Read unknown/unsupported register 0x%02x\n", offset);
312     }
313 
314     if (old_isr != blk->isr) {
315         update_irq(dev, block);
316     }
317 
318     return ret;
319 }
320 
321 static void io_write(IPackDevice *ip, uint8_t addr, uint16_t val)
322 {
323     IPOctalState *dev = IPOCTAL(ip);
324     unsigned reg = val & 0xFF;
325     /* addr[7:6]: block   (A-D)
326        addr[7:5]: channel (a-h)
327        addr[5:0]: register */
328     unsigned block = addr >> 5;
329     unsigned channel = addr >> 4;
330     /* Big endian, accessed using 8-bit bytes at odd locations */
331     unsigned offset = (addr & 0x1F) ^ 1;
332     SCC2698Channel *ch = &dev->ch[channel];
333     SCC2698Block *blk = &dev->blk[block];
334     uint8_t old_isr = blk->isr;
335     uint8_t old_imr = blk->imr;
336 
337     switch (offset) {
338 
339     case REG_MRa:
340     case REG_MRb:
341         ch->mr[ch->mr_idx] = reg;
342         DPRINTF("Write MR%u%c 0x%x\n", ch->mr_idx + 1, channel + 'a', reg);
343         ch->mr_idx = 1;
344         break;
345 
346     /* Not implemented */
347     case REG_CSRa:
348     case REG_CSRb:
349         DPRINTF("Write CSR%c: 0x%x\n", channel + 'a', reg);
350         break;
351 
352     case REG_CRa:
353     case REG_CRb:
354         write_cr(dev, channel, reg);
355         break;
356 
357     case REG_THRa:
358     case REG_THRb:
359         if (ch->sr & SR_TXRDY) {
360             uint8_t thr = reg;
361             DPRINTF("Write THR%c (0x%x)\n", channel + 'a', reg);
362             /* XXX this blocks entire thread. Rewrite to use
363              * qemu_chr_fe_write and background I/O callbacks */
364             qemu_chr_fe_write_all(&ch->dev, &thr, 1);
365         } else {
366             DPRINTF("Write THR%c (0x%x), Tx disabled\n", channel + 'a', reg);
367         }
368         break;
369 
370     /* Not implemented */
371     case REG_ACR:
372         DPRINTF("Write ACR%c 0x%x\n", block + 'A', val);
373         break;
374 
375     case REG_IMR:
376         DPRINTF("Write IMR%c 0x%x\n", block + 'A', val);
377         blk->imr = reg;
378         break;
379 
380     /* Not implemented */
381     case REG_OPCR:
382         DPRINTF("Write OPCR%c 0x%x\n", block + 'A', val);
383         break;
384 
385     default:
386         DPRINTF("Write unknown/unsupported register 0x%02x %u\n", offset, val);
387     }
388 
389     if (old_isr != blk->isr || old_imr != blk->imr) {
390         update_irq(dev, block);
391     }
392 }
393 
394 static uint16_t id_read(IPackDevice *ip, uint8_t addr)
395 {
396     uint16_t ret = 0;
397     unsigned pos = addr / 2; /* The ID PROM data is stored every other byte */
398 
399     if (pos < ARRAY_SIZE(id_prom_data)) {
400         ret = id_prom_data[pos];
401     } else {
402         DPRINTF("Attempt to read unavailable PROM data at 0x%x\n",  addr);
403     }
404 
405     return ret;
406 }
407 
408 static void id_write(IPackDevice *ip, uint8_t addr, uint16_t val)
409 {
410     IPOctalState *dev = IPOCTAL(ip);
411     if (addr == 1) {
412         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
413         dev->irq_vector = val; /* Undocumented, but the hw works like that */
414     } else {
415         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
416     }
417 }
418 
419 static uint16_t int_read(IPackDevice *ip, uint8_t addr)
420 {
421     IPOctalState *dev = IPOCTAL(ip);
422     /* Read address 0 to ACK INT0# and address 2 to ACK INT1# */
423     if (addr != 0 && addr != 2) {
424         DPRINTF("Attempt to read from 0x%x\n", addr);
425         return 0;
426     } else {
427         /* Update interrupts if necessary */
428         update_irq(dev, addr);
429         return dev->irq_vector;
430     }
431 }
432 
433 static void int_write(IPackDevice *ip, uint8_t addr, uint16_t val)
434 {
435     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
436 }
437 
438 static uint16_t mem_read16(IPackDevice *ip, uint32_t addr)
439 {
440     DPRINTF("Attempt to read from 0x%x\n", addr);
441     return 0;
442 }
443 
444 static void mem_write16(IPackDevice *ip, uint32_t addr, uint16_t val)
445 {
446     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
447 }
448 
449 static uint8_t mem_read8(IPackDevice *ip, uint32_t addr)
450 {
451     DPRINTF("Attempt to read from 0x%x\n", addr);
452     return 0;
453 }
454 
455 static void mem_write8(IPackDevice *ip, uint32_t addr, uint8_t val)
456 {
457     IPOctalState *dev = IPOCTAL(ip);
458     if (addr == 1) {
459         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
460         dev->irq_vector = val;
461     } else {
462         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
463     }
464 }
465 
466 static int hostdev_can_receive(void *opaque)
467 {
468     SCC2698Channel *ch = opaque;
469     int available_bytes = RX_FIFO_SIZE - ch->rx_pending;
470     return ch->rx_enabled ? available_bytes : 0;
471 }
472 
473 static void hostdev_receive(void *opaque, const uint8_t *buf, int size)
474 {
475     SCC2698Channel *ch = opaque;
476     IPOctalState *dev = ch->ipoctal;
477     unsigned pos = ch->rhr_idx + ch->rx_pending;
478     int i;
479 
480     assert(size + ch->rx_pending <= RX_FIFO_SIZE);
481 
482     /* Copy data to the RxFIFO */
483     for (i = 0; i < size; i++) {
484         pos %= RX_FIFO_SIZE;
485         ch->rhr[pos++] = buf[i];
486     }
487 
488     ch->rx_pending += size;
489 
490     /* If the RxFIFO was empty raise an interrupt */
491     if (!(ch->sr & SR_RXRDY)) {
492         unsigned block, channel = 0;
493         /* Find channel number to update the ISR register */
494         while (&dev->ch[channel] != ch) {
495             channel++;
496         }
497         block = channel / 2;
498         dev->blk[block].isr |= ISR_RXRDY(channel);
499         ch->sr |= SR_RXRDY;
500         update_irq(dev, block);
501     }
502 }
503 
504 static void hostdev_event(void *opaque, int event)
505 {
506     SCC2698Channel *ch = opaque;
507     switch (event) {
508     case CHR_EVENT_OPENED:
509         DPRINTF("Device %s opened\n", ch->dev->label);
510         break;
511     case CHR_EVENT_BREAK: {
512         uint8_t zero = 0;
513         DPRINTF("Device %s received break\n", ch->dev->label);
514 
515         if (!(ch->sr & SR_BREAK)) {
516             IPOctalState *dev = ch->ipoctal;
517             unsigned block, channel = 0;
518 
519             while (&dev->ch[channel] != ch) {
520                 channel++;
521             }
522             block = channel / 2;
523 
524             ch->sr |= SR_BREAK;
525             dev->blk[block].isr |= ISR_BREAK(channel);
526         }
527 
528         /* Put a zero character in the buffer */
529         hostdev_receive(ch, &zero, 1);
530     }
531         break;
532     default:
533         DPRINTF("Device %s received event %d\n", ch->dev->label, event);
534     }
535 }
536 
537 static void ipoctal_realize(DeviceState *dev, Error **errp)
538 {
539     IPOctalState *s = IPOCTAL(dev);
540     unsigned i;
541 
542     for (i = 0; i < N_CHANNELS; i++) {
543         SCC2698Channel *ch = &s->ch[i];
544         ch->ipoctal = s;
545 
546         /* Redirect IP-Octal channels to host character devices */
547         if (qemu_chr_fe_backend_connected(&ch->dev)) {
548             qemu_chr_fe_set_handlers(&ch->dev, hostdev_can_receive,
549                                      hostdev_receive, hostdev_event,
550                                      NULL, ch, NULL, true);
551             DPRINTF("Redirecting channel %u to %s\n", i, ch->dev->label);
552         } else {
553             DPRINTF("Could not redirect channel %u, no chardev set\n", i);
554         }
555     }
556 }
557 
558 static Property ipoctal_properties[] = {
559     DEFINE_PROP_CHR("chardev0", IPOctalState, ch[0].dev),
560     DEFINE_PROP_CHR("chardev1", IPOctalState, ch[1].dev),
561     DEFINE_PROP_CHR("chardev2", IPOctalState, ch[2].dev),
562     DEFINE_PROP_CHR("chardev3", IPOctalState, ch[3].dev),
563     DEFINE_PROP_CHR("chardev4", IPOctalState, ch[4].dev),
564     DEFINE_PROP_CHR("chardev5", IPOctalState, ch[5].dev),
565     DEFINE_PROP_CHR("chardev6", IPOctalState, ch[6].dev),
566     DEFINE_PROP_CHR("chardev7", IPOctalState, ch[7].dev),
567     DEFINE_PROP_END_OF_LIST(),
568 };
569 
570 static void ipoctal_class_init(ObjectClass *klass, void *data)
571 {
572     DeviceClass *dc = DEVICE_CLASS(klass);
573     IPackDeviceClass *ic = IPACK_DEVICE_CLASS(klass);
574 
575     ic->realize     = ipoctal_realize;
576     ic->io_read     = io_read;
577     ic->io_write    = io_write;
578     ic->id_read     = id_read;
579     ic->id_write    = id_write;
580     ic->int_read    = int_read;
581     ic->int_write   = int_write;
582     ic->mem_read16  = mem_read16;
583     ic->mem_write16 = mem_write16;
584     ic->mem_read8   = mem_read8;
585     ic->mem_write8  = mem_write8;
586 
587     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
588     dc->desc    = "GE IP-Octal 232 8-channel RS-232 IndustryPack";
589     dc->props   = ipoctal_properties;
590     dc->vmsd    = &vmstate_ipoctal;
591 }
592 
593 static const TypeInfo ipoctal_info = {
594     .name          = TYPE_IPOCTAL,
595     .parent        = TYPE_IPACK_DEVICE,
596     .instance_size = sizeof(IPOctalState),
597     .class_init    = ipoctal_class_init,
598 };
599 
600 static void ipoctal_register_types(void)
601 {
602     type_register_static(&ipoctal_info);
603 }
604 
605 type_init(ipoctal_register_types)
606