xref: /openbmc/qemu/hw/char/ipoctal232.c (revision 135b03cb)
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 "hw/qdev-properties.h"
15 #include "migration/vmstate.h"
16 #include "qemu/bitops.h"
17 #include "qemu/module.h"
18 #include "chardev/char-fe.h"
19 
20 /* #define DEBUG_IPOCTAL */
21 
22 #ifdef DEBUG_IPOCTAL
23 #define DPRINTF2(fmt, ...) \
24     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
25 #else
26 #define DPRINTF2(fmt, ...) do { } while (0)
27 #endif
28 
29 #define DPRINTF(fmt, ...) DPRINTF2("IP-Octal: " fmt, ## __VA_ARGS__)
30 
31 #define RX_FIFO_SIZE 3
32 
33 /* The IP-Octal has 8 channels (a-h)
34    divided into 4 blocks (A-D) */
35 #define N_CHANNELS 8
36 #define N_BLOCKS   4
37 
38 #define REG_MRa  0x01
39 #define REG_MRb  0x11
40 #define REG_SRa  0x03
41 #define REG_SRb  0x13
42 #define REG_CSRa 0x03
43 #define REG_CSRb 0x13
44 #define REG_CRa  0x05
45 #define REG_CRb  0x15
46 #define REG_RHRa 0x07
47 #define REG_RHRb 0x17
48 #define REG_THRa 0x07
49 #define REG_THRb 0x17
50 #define REG_ACR  0x09
51 #define REG_ISR  0x0B
52 #define REG_IMR  0x0B
53 #define REG_OPCR 0x1B
54 
55 #define CR_ENABLE_RX    BIT(0)
56 #define CR_DISABLE_RX   BIT(1)
57 #define CR_ENABLE_TX    BIT(2)
58 #define CR_DISABLE_TX   BIT(3)
59 #define CR_CMD(cr)      ((cr) >> 4)
60 #define CR_NO_OP        0
61 #define CR_RESET_MR     1
62 #define CR_RESET_RX     2
63 #define CR_RESET_TX     3
64 #define CR_RESET_ERR    4
65 #define CR_RESET_BRKINT 5
66 #define CR_START_BRK    6
67 #define CR_STOP_BRK     7
68 #define CR_ASSERT_RTSN  8
69 #define CR_NEGATE_RTSN  9
70 #define CR_TIMEOUT_ON   10
71 #define CR_TIMEOUT_OFF  12
72 
73 #define SR_RXRDY   BIT(0)
74 #define SR_FFULL   BIT(1)
75 #define SR_TXRDY   BIT(2)
76 #define SR_TXEMT   BIT(3)
77 #define SR_OVERRUN BIT(4)
78 #define SR_PARITY  BIT(5)
79 #define SR_FRAMING BIT(6)
80 #define SR_BREAK   BIT(7)
81 
82 #define ISR_TXRDYA BIT(0)
83 #define ISR_RXRDYA BIT(1)
84 #define ISR_BREAKA BIT(2)
85 #define ISR_CNTRDY BIT(3)
86 #define ISR_TXRDYB BIT(4)
87 #define ISR_RXRDYB BIT(5)
88 #define ISR_BREAKB BIT(6)
89 #define ISR_MPICHG BIT(7)
90 #define ISR_TXRDY(CH) (((CH) & 1) ? BIT(4) : BIT(0))
91 #define ISR_RXRDY(CH) (((CH) & 1) ? BIT(5) : BIT(1))
92 #define ISR_BREAK(CH) (((CH) & 1) ? BIT(6) : BIT(2))
93 
94 typedef struct IPOctalState IPOctalState;
95 typedef struct SCC2698Channel SCC2698Channel;
96 typedef struct SCC2698Block SCC2698Block;
97 
98 struct SCC2698Channel {
99     IPOctalState *ipoctal;
100     CharBackend dev;
101     bool rx_enabled;
102     uint8_t mr[2];
103     uint8_t mr_idx;
104     uint8_t sr;
105     uint8_t rhr[RX_FIFO_SIZE];
106     uint8_t rhr_idx;
107     uint8_t rx_pending;
108 };
109 
110 struct SCC2698Block {
111     uint8_t imr;
112     uint8_t isr;
113 };
114 
115 struct IPOctalState {
116     IPackDevice parent_obj;
117 
118     SCC2698Channel ch[N_CHANNELS];
119     SCC2698Block blk[N_BLOCKS];
120     uint8_t irq_vector;
121 };
122 
123 #define TYPE_IPOCTAL "ipoctal232"
124 
125 #define IPOCTAL(obj) \
126     OBJECT_CHECK(IPOctalState, (obj), TYPE_IPOCTAL)
127 
128 static const VMStateDescription vmstate_scc2698_channel = {
129     .name = "scc2698_channel",
130     .version_id = 1,
131     .minimum_version_id = 1,
132     .fields = (VMStateField[]) {
133         VMSTATE_BOOL(rx_enabled, SCC2698Channel),
134         VMSTATE_UINT8_ARRAY(mr, SCC2698Channel, 2),
135         VMSTATE_UINT8(mr_idx, SCC2698Channel),
136         VMSTATE_UINT8(sr, SCC2698Channel),
137         VMSTATE_UINT8_ARRAY(rhr, SCC2698Channel, RX_FIFO_SIZE),
138         VMSTATE_UINT8(rhr_idx, SCC2698Channel),
139         VMSTATE_UINT8(rx_pending, SCC2698Channel),
140         VMSTATE_END_OF_LIST()
141     }
142 };
143 
144 static const VMStateDescription vmstate_scc2698_block = {
145     .name = "scc2698_block",
146     .version_id = 1,
147     .minimum_version_id = 1,
148     .fields = (VMStateField[]) {
149         VMSTATE_UINT8(imr, SCC2698Block),
150         VMSTATE_UINT8(isr, SCC2698Block),
151         VMSTATE_END_OF_LIST()
152     }
153 };
154 
155 static const VMStateDescription vmstate_ipoctal = {
156     .name = "ipoctal232",
157     .version_id = 1,
158     .minimum_version_id = 1,
159     .fields = (VMStateField[]) {
160         VMSTATE_IPACK_DEVICE(parent_obj, IPOctalState),
161         VMSTATE_STRUCT_ARRAY(ch, IPOctalState, N_CHANNELS, 1,
162                              vmstate_scc2698_channel, SCC2698Channel),
163         VMSTATE_STRUCT_ARRAY(blk, IPOctalState, N_BLOCKS, 1,
164                              vmstate_scc2698_block, SCC2698Block),
165         VMSTATE_UINT8(irq_vector, IPOctalState),
166         VMSTATE_END_OF_LIST()
167     }
168 };
169 
170 /* data[10] is 0x0C, not 0x0B as the doc says */
171 static const uint8_t id_prom_data[] = {
172     0x49, 0x50, 0x41, 0x43, 0xF0, 0x22,
173     0xA1, 0x00, 0x00, 0x00, 0x0C, 0xCC
174 };
175 
176 static void update_irq(IPOctalState *dev, unsigned block)
177 {
178     IPackDevice *idev = IPACK_DEVICE(dev);
179     /* Blocks A and B interrupt on INT0#, C and D on INT1#.
180        Thus, to get the status we have to check two blocks. */
181     SCC2698Block *blk0 = &dev->blk[block];
182     SCC2698Block *blk1 = &dev->blk[block^1];
183     unsigned intno = block / 2;
184 
185     if ((blk0->isr & blk0->imr) || (blk1->isr & blk1->imr)) {
186         qemu_irq_raise(idev->irq[intno]);
187     } else {
188         qemu_irq_lower(idev->irq[intno]);
189     }
190 }
191 
192 static void write_cr(IPOctalState *dev, unsigned channel, uint8_t val)
193 {
194     SCC2698Channel *ch = &dev->ch[channel];
195     SCC2698Block *blk = &dev->blk[channel / 2];
196 
197     DPRINTF("Write CR%c %u: ", channel + 'a', val);
198 
199     /* The lower 4 bits are used to enable and disable Tx and Rx */
200     if (val & CR_ENABLE_RX) {
201         DPRINTF2("Rx on, ");
202         ch->rx_enabled = true;
203     }
204     if (val & CR_DISABLE_RX) {
205         DPRINTF2("Rx off, ");
206         ch->rx_enabled = false;
207     }
208     if (val & CR_ENABLE_TX) {
209         DPRINTF2("Tx on, ");
210         ch->sr |= SR_TXRDY | SR_TXEMT;
211         blk->isr |= ISR_TXRDY(channel);
212     }
213     if (val & CR_DISABLE_TX) {
214         DPRINTF2("Tx off, ");
215         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
216         blk->isr &= ~ISR_TXRDY(channel);
217     }
218 
219     DPRINTF2("cmd: ");
220 
221     /* The rest of the bits implement different commands */
222     switch (CR_CMD(val)) {
223     case CR_NO_OP:
224         DPRINTF2("none");
225         break;
226     case CR_RESET_MR:
227         DPRINTF2("reset MR");
228         ch->mr_idx = 0;
229         break;
230     case CR_RESET_RX:
231         DPRINTF2("reset Rx");
232         ch->rx_enabled = false;
233         ch->rx_pending = 0;
234         ch->sr &= ~SR_RXRDY;
235         blk->isr &= ~ISR_RXRDY(channel);
236         break;
237     case CR_RESET_TX:
238         DPRINTF2("reset Tx");
239         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
240         blk->isr &= ~ISR_TXRDY(channel);
241         break;
242     case CR_RESET_ERR:
243         DPRINTF2("reset err");
244         ch->sr &= ~(SR_OVERRUN | SR_PARITY | SR_FRAMING | SR_BREAK);
245         break;
246     case CR_RESET_BRKINT:
247         DPRINTF2("reset brk ch int");
248         blk->isr &= ~(ISR_BREAKA | ISR_BREAKB);
249         break;
250     default:
251         DPRINTF2("unsupported 0x%x", CR_CMD(val));
252     }
253 
254     DPRINTF2("\n");
255 }
256 
257 static uint16_t io_read(IPackDevice *ip, uint8_t addr)
258 {
259     IPOctalState *dev = IPOCTAL(ip);
260     uint16_t ret = 0;
261     /* addr[7:6]: block   (A-D)
262        addr[7:5]: channel (a-h)
263        addr[5:0]: register */
264     unsigned block = addr >> 5;
265     unsigned channel = addr >> 4;
266     /* Big endian, accessed using 8-bit bytes at odd locations */
267     unsigned offset = (addr & 0x1F) ^ 1;
268     SCC2698Channel *ch = &dev->ch[channel];
269     SCC2698Block *blk = &dev->blk[block];
270     uint8_t old_isr = blk->isr;
271 
272     switch (offset) {
273 
274     case REG_MRa:
275     case REG_MRb:
276         ret = ch->mr[ch->mr_idx];
277         DPRINTF("Read MR%u%c: 0x%x\n", ch->mr_idx + 1, channel + 'a', ret);
278         ch->mr_idx = 1;
279         break;
280 
281     case REG_SRa:
282     case REG_SRb:
283         ret = ch->sr;
284         DPRINTF("Read SR%c: 0x%x\n", channel + 'a', ret);
285         break;
286 
287     case REG_RHRa:
288     case REG_RHRb:
289         ret = ch->rhr[ch->rhr_idx];
290         if (ch->rx_pending > 0) {
291             ch->rx_pending--;
292             if (ch->rx_pending == 0) {
293                 ch->sr &= ~SR_RXRDY;
294                 blk->isr &= ~ISR_RXRDY(channel);
295                 qemu_chr_fe_accept_input(&ch->dev);
296             } else {
297                 ch->rhr_idx = (ch->rhr_idx + 1) % RX_FIFO_SIZE;
298             }
299             if (ch->sr & SR_BREAK) {
300                 ch->sr &= ~SR_BREAK;
301                 blk->isr |= ISR_BREAK(channel);
302             }
303         }
304         DPRINTF("Read RHR%c (0x%x)\n", channel + 'a', ret);
305         break;
306 
307     case REG_ISR:
308         ret = blk->isr;
309         DPRINTF("Read ISR%c: 0x%x\n", block + 'A', ret);
310         break;
311 
312     default:
313         DPRINTF("Read unknown/unsupported register 0x%02x\n", offset);
314     }
315 
316     if (old_isr != blk->isr) {
317         update_irq(dev, block);
318     }
319 
320     return ret;
321 }
322 
323 static void io_write(IPackDevice *ip, uint8_t addr, uint16_t val)
324 {
325     IPOctalState *dev = IPOCTAL(ip);
326     unsigned reg = val & 0xFF;
327     /* addr[7:6]: block   (A-D)
328        addr[7:5]: channel (a-h)
329        addr[5:0]: register */
330     unsigned block = addr >> 5;
331     unsigned channel = addr >> 4;
332     /* Big endian, accessed using 8-bit bytes at odd locations */
333     unsigned offset = (addr & 0x1F) ^ 1;
334     SCC2698Channel *ch = &dev->ch[channel];
335     SCC2698Block *blk = &dev->blk[block];
336     uint8_t old_isr = blk->isr;
337     uint8_t old_imr = blk->imr;
338 
339     switch (offset) {
340 
341     case REG_MRa:
342     case REG_MRb:
343         ch->mr[ch->mr_idx] = reg;
344         DPRINTF("Write MR%u%c 0x%x\n", ch->mr_idx + 1, channel + 'a', reg);
345         ch->mr_idx = 1;
346         break;
347 
348     /* Not implemented */
349     case REG_CSRa:
350     case REG_CSRb:
351         DPRINTF("Write CSR%c: 0x%x\n", channel + 'a', reg);
352         break;
353 
354     case REG_CRa:
355     case REG_CRb:
356         write_cr(dev, channel, reg);
357         break;
358 
359     case REG_THRa:
360     case REG_THRb:
361         if (ch->sr & SR_TXRDY) {
362             uint8_t thr = reg;
363             DPRINTF("Write THR%c (0x%x)\n", channel + 'a', reg);
364             /* XXX this blocks entire thread. Rewrite to use
365              * qemu_chr_fe_write and background I/O callbacks */
366             qemu_chr_fe_write_all(&ch->dev, &thr, 1);
367         } else {
368             DPRINTF("Write THR%c (0x%x), Tx disabled\n", channel + 'a', reg);
369         }
370         break;
371 
372     /* Not implemented */
373     case REG_ACR:
374         DPRINTF("Write ACR%c 0x%x\n", block + 'A', val);
375         break;
376 
377     case REG_IMR:
378         DPRINTF("Write IMR%c 0x%x\n", block + 'A', val);
379         blk->imr = reg;
380         break;
381 
382     /* Not implemented */
383     case REG_OPCR:
384         DPRINTF("Write OPCR%c 0x%x\n", block + 'A', val);
385         break;
386 
387     default:
388         DPRINTF("Write unknown/unsupported register 0x%02x %u\n", offset, val);
389     }
390 
391     if (old_isr != blk->isr || old_imr != blk->imr) {
392         update_irq(dev, block);
393     }
394 }
395 
396 static uint16_t id_read(IPackDevice *ip, uint8_t addr)
397 {
398     uint16_t ret = 0;
399     unsigned pos = addr / 2; /* The ID PROM data is stored every other byte */
400 
401     if (pos < ARRAY_SIZE(id_prom_data)) {
402         ret = id_prom_data[pos];
403     } else {
404         DPRINTF("Attempt to read unavailable PROM data at 0x%x\n",  addr);
405     }
406 
407     return ret;
408 }
409 
410 static void id_write(IPackDevice *ip, uint8_t addr, uint16_t val)
411 {
412     IPOctalState *dev = IPOCTAL(ip);
413     if (addr == 1) {
414         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
415         dev->irq_vector = val; /* Undocumented, but the hw works like that */
416     } else {
417         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
418     }
419 }
420 
421 static uint16_t int_read(IPackDevice *ip, uint8_t addr)
422 {
423     IPOctalState *dev = IPOCTAL(ip);
424     /* Read address 0 to ACK INT0# and address 2 to ACK INT1# */
425     if (addr != 0 && addr != 2) {
426         DPRINTF("Attempt to read from 0x%x\n", addr);
427         return 0;
428     } else {
429         /* Update interrupts if necessary */
430         update_irq(dev, addr);
431         return dev->irq_vector;
432     }
433 }
434 
435 static void int_write(IPackDevice *ip, uint8_t addr, uint16_t val)
436 {
437     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
438 }
439 
440 static uint16_t mem_read16(IPackDevice *ip, uint32_t addr)
441 {
442     DPRINTF("Attempt to read from 0x%x\n", addr);
443     return 0;
444 }
445 
446 static void mem_write16(IPackDevice *ip, uint32_t addr, uint16_t val)
447 {
448     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
449 }
450 
451 static uint8_t mem_read8(IPackDevice *ip, uint32_t addr)
452 {
453     DPRINTF("Attempt to read from 0x%x\n", addr);
454     return 0;
455 }
456 
457 static void mem_write8(IPackDevice *ip, uint32_t addr, uint8_t val)
458 {
459     IPOctalState *dev = IPOCTAL(ip);
460     if (addr == 1) {
461         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
462         dev->irq_vector = val;
463     } else {
464         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
465     }
466 }
467 
468 static int hostdev_can_receive(void *opaque)
469 {
470     SCC2698Channel *ch = opaque;
471     int available_bytes = RX_FIFO_SIZE - ch->rx_pending;
472     return ch->rx_enabled ? available_bytes : 0;
473 }
474 
475 static void hostdev_receive(void *opaque, const uint8_t *buf, int size)
476 {
477     SCC2698Channel *ch = opaque;
478     IPOctalState *dev = ch->ipoctal;
479     unsigned pos = ch->rhr_idx + ch->rx_pending;
480     int i;
481 
482     assert(size + ch->rx_pending <= RX_FIFO_SIZE);
483 
484     /* Copy data to the RxFIFO */
485     for (i = 0; i < size; i++) {
486         pos %= RX_FIFO_SIZE;
487         ch->rhr[pos++] = buf[i];
488     }
489 
490     ch->rx_pending += size;
491 
492     /* If the RxFIFO was empty raise an interrupt */
493     if (!(ch->sr & SR_RXRDY)) {
494         unsigned block, channel = 0;
495         /* Find channel number to update the ISR register */
496         while (&dev->ch[channel] != ch) {
497             channel++;
498         }
499         block = channel / 2;
500         dev->blk[block].isr |= ISR_RXRDY(channel);
501         ch->sr |= SR_RXRDY;
502         update_irq(dev, block);
503     }
504 }
505 
506 static void hostdev_event(void *opaque, int event)
507 {
508     SCC2698Channel *ch = opaque;
509     switch (event) {
510     case CHR_EVENT_OPENED:
511         DPRINTF("Device %s opened\n", ch->dev->label);
512         break;
513     case CHR_EVENT_BREAK: {
514         uint8_t zero = 0;
515         DPRINTF("Device %s received break\n", ch->dev->label);
516 
517         if (!(ch->sr & SR_BREAK)) {
518             IPOctalState *dev = ch->ipoctal;
519             unsigned block, channel = 0;
520 
521             while (&dev->ch[channel] != ch) {
522                 channel++;
523             }
524             block = channel / 2;
525 
526             ch->sr |= SR_BREAK;
527             dev->blk[block].isr |= ISR_BREAK(channel);
528         }
529 
530         /* Put a zero character in the buffer */
531         hostdev_receive(ch, &zero, 1);
532     }
533         break;
534     default:
535         DPRINTF("Device %s received event %d\n", ch->dev->label, event);
536     }
537 }
538 
539 static void ipoctal_realize(DeviceState *dev, Error **errp)
540 {
541     IPOctalState *s = IPOCTAL(dev);
542     unsigned i;
543 
544     for (i = 0; i < N_CHANNELS; i++) {
545         SCC2698Channel *ch = &s->ch[i];
546         ch->ipoctal = s;
547 
548         /* Redirect IP-Octal channels to host character devices */
549         if (qemu_chr_fe_backend_connected(&ch->dev)) {
550             qemu_chr_fe_set_handlers(&ch->dev, hostdev_can_receive,
551                                      hostdev_receive, hostdev_event,
552                                      NULL, ch, NULL, true);
553             DPRINTF("Redirecting channel %u to %s\n", i, ch->dev->label);
554         } else {
555             DPRINTF("Could not redirect channel %u, no chardev set\n", i);
556         }
557     }
558 }
559 
560 static Property ipoctal_properties[] = {
561     DEFINE_PROP_CHR("chardev0", IPOctalState, ch[0].dev),
562     DEFINE_PROP_CHR("chardev1", IPOctalState, ch[1].dev),
563     DEFINE_PROP_CHR("chardev2", IPOctalState, ch[2].dev),
564     DEFINE_PROP_CHR("chardev3", IPOctalState, ch[3].dev),
565     DEFINE_PROP_CHR("chardev4", IPOctalState, ch[4].dev),
566     DEFINE_PROP_CHR("chardev5", IPOctalState, ch[5].dev),
567     DEFINE_PROP_CHR("chardev6", IPOctalState, ch[6].dev),
568     DEFINE_PROP_CHR("chardev7", IPOctalState, ch[7].dev),
569     DEFINE_PROP_END_OF_LIST(),
570 };
571 
572 static void ipoctal_class_init(ObjectClass *klass, void *data)
573 {
574     DeviceClass *dc = DEVICE_CLASS(klass);
575     IPackDeviceClass *ic = IPACK_DEVICE_CLASS(klass);
576 
577     ic->realize     = ipoctal_realize;
578     ic->io_read     = io_read;
579     ic->io_write    = io_write;
580     ic->id_read     = id_read;
581     ic->id_write    = id_write;
582     ic->int_read    = int_read;
583     ic->int_write   = int_write;
584     ic->mem_read16  = mem_read16;
585     ic->mem_write16 = mem_write16;
586     ic->mem_read8   = mem_read8;
587     ic->mem_write8  = mem_write8;
588 
589     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
590     dc->desc    = "GE IP-Octal 232 8-channel RS-232 IndustryPack";
591     dc->props   = ipoctal_properties;
592     dc->vmsd    = &vmstate_ipoctal;
593 }
594 
595 static const TypeInfo ipoctal_info = {
596     .name          = TYPE_IPOCTAL,
597     .parent        = TYPE_IPACK_DEVICE,
598     .instance_size = sizeof(IPOctalState),
599     .class_init    = ipoctal_class_init,
600 };
601 
602 static void ipoctal_register_types(void)
603 {
604     type_register_static(&ipoctal_info);
605 }
606 
607 type_init(ipoctal_register_types)
608