xref: /openbmc/qemu/hw/char/ipoctal232.c (revision 500eb6db)
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 "qemu/module.h"
15 #include "chardev/char-fe.h"
16 
17 /* #define DEBUG_IPOCTAL */
18 
19 #ifdef DEBUG_IPOCTAL
20 #define DPRINTF2(fmt, ...) \
21     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
22 #else
23 #define DPRINTF2(fmt, ...) do { } while (0)
24 #endif
25 
26 #define DPRINTF(fmt, ...) DPRINTF2("IP-Octal: " fmt, ## __VA_ARGS__)
27 
28 #define RX_FIFO_SIZE 3
29 
30 /* The IP-Octal has 8 channels (a-h)
31    divided into 4 blocks (A-D) */
32 #define N_CHANNELS 8
33 #define N_BLOCKS   4
34 
35 #define REG_MRa  0x01
36 #define REG_MRb  0x11
37 #define REG_SRa  0x03
38 #define REG_SRb  0x13
39 #define REG_CSRa 0x03
40 #define REG_CSRb 0x13
41 #define REG_CRa  0x05
42 #define REG_CRb  0x15
43 #define REG_RHRa 0x07
44 #define REG_RHRb 0x17
45 #define REG_THRa 0x07
46 #define REG_THRb 0x17
47 #define REG_ACR  0x09
48 #define REG_ISR  0x0B
49 #define REG_IMR  0x0B
50 #define REG_OPCR 0x1B
51 
52 #define CR_ENABLE_RX    BIT(0)
53 #define CR_DISABLE_RX   BIT(1)
54 #define CR_ENABLE_TX    BIT(2)
55 #define CR_DISABLE_TX   BIT(3)
56 #define CR_CMD(cr)      ((cr) >> 4)
57 #define CR_NO_OP        0
58 #define CR_RESET_MR     1
59 #define CR_RESET_RX     2
60 #define CR_RESET_TX     3
61 #define CR_RESET_ERR    4
62 #define CR_RESET_BRKINT 5
63 #define CR_START_BRK    6
64 #define CR_STOP_BRK     7
65 #define CR_ASSERT_RTSN  8
66 #define CR_NEGATE_RTSN  9
67 #define CR_TIMEOUT_ON   10
68 #define CR_TIMEOUT_OFF  12
69 
70 #define SR_RXRDY   BIT(0)
71 #define SR_FFULL   BIT(1)
72 #define SR_TXRDY   BIT(2)
73 #define SR_TXEMT   BIT(3)
74 #define SR_OVERRUN BIT(4)
75 #define SR_PARITY  BIT(5)
76 #define SR_FRAMING BIT(6)
77 #define SR_BREAK   BIT(7)
78 
79 #define ISR_TXRDYA BIT(0)
80 #define ISR_RXRDYA BIT(1)
81 #define ISR_BREAKA BIT(2)
82 #define ISR_CNTRDY BIT(3)
83 #define ISR_TXRDYB BIT(4)
84 #define ISR_RXRDYB BIT(5)
85 #define ISR_BREAKB BIT(6)
86 #define ISR_MPICHG BIT(7)
87 #define ISR_TXRDY(CH) (((CH) & 1) ? BIT(4) : BIT(0))
88 #define ISR_RXRDY(CH) (((CH) & 1) ? BIT(5) : BIT(1))
89 #define ISR_BREAK(CH) (((CH) & 1) ? BIT(6) : BIT(2))
90 
91 typedef struct IPOctalState IPOctalState;
92 typedef struct SCC2698Channel SCC2698Channel;
93 typedef struct SCC2698Block SCC2698Block;
94 
95 struct SCC2698Channel {
96     IPOctalState *ipoctal;
97     CharBackend dev;
98     bool rx_enabled;
99     uint8_t mr[2];
100     uint8_t mr_idx;
101     uint8_t sr;
102     uint8_t rhr[RX_FIFO_SIZE];
103     uint8_t rhr_idx;
104     uint8_t rx_pending;
105 };
106 
107 struct SCC2698Block {
108     uint8_t imr;
109     uint8_t isr;
110 };
111 
112 struct IPOctalState {
113     IPackDevice parent_obj;
114 
115     SCC2698Channel ch[N_CHANNELS];
116     SCC2698Block blk[N_BLOCKS];
117     uint8_t irq_vector;
118 };
119 
120 #define TYPE_IPOCTAL "ipoctal232"
121 
122 #define IPOCTAL(obj) \
123     OBJECT_CHECK(IPOctalState, (obj), TYPE_IPOCTAL)
124 
125 static const VMStateDescription vmstate_scc2698_channel = {
126     .name = "scc2698_channel",
127     .version_id = 1,
128     .minimum_version_id = 1,
129     .fields = (VMStateField[]) {
130         VMSTATE_BOOL(rx_enabled, SCC2698Channel),
131         VMSTATE_UINT8_ARRAY(mr, SCC2698Channel, 2),
132         VMSTATE_UINT8(mr_idx, SCC2698Channel),
133         VMSTATE_UINT8(sr, SCC2698Channel),
134         VMSTATE_UINT8_ARRAY(rhr, SCC2698Channel, RX_FIFO_SIZE),
135         VMSTATE_UINT8(rhr_idx, SCC2698Channel),
136         VMSTATE_UINT8(rx_pending, SCC2698Channel),
137         VMSTATE_END_OF_LIST()
138     }
139 };
140 
141 static const VMStateDescription vmstate_scc2698_block = {
142     .name = "scc2698_block",
143     .version_id = 1,
144     .minimum_version_id = 1,
145     .fields = (VMStateField[]) {
146         VMSTATE_UINT8(imr, SCC2698Block),
147         VMSTATE_UINT8(isr, SCC2698Block),
148         VMSTATE_END_OF_LIST()
149     }
150 };
151 
152 static const VMStateDescription vmstate_ipoctal = {
153     .name = "ipoctal232",
154     .version_id = 1,
155     .minimum_version_id = 1,
156     .fields = (VMStateField[]) {
157         VMSTATE_IPACK_DEVICE(parent_obj, IPOctalState),
158         VMSTATE_STRUCT_ARRAY(ch, IPOctalState, N_CHANNELS, 1,
159                              vmstate_scc2698_channel, SCC2698Channel),
160         VMSTATE_STRUCT_ARRAY(blk, IPOctalState, N_BLOCKS, 1,
161                              vmstate_scc2698_block, SCC2698Block),
162         VMSTATE_UINT8(irq_vector, IPOctalState),
163         VMSTATE_END_OF_LIST()
164     }
165 };
166 
167 /* data[10] is 0x0C, not 0x0B as the doc says */
168 static const uint8_t id_prom_data[] = {
169     0x49, 0x50, 0x41, 0x43, 0xF0, 0x22,
170     0xA1, 0x00, 0x00, 0x00, 0x0C, 0xCC
171 };
172 
173 static void update_irq(IPOctalState *dev, unsigned block)
174 {
175     IPackDevice *idev = IPACK_DEVICE(dev);
176     /* Blocks A and B interrupt on INT0#, C and D on INT1#.
177        Thus, to get the status we have to check two blocks. */
178     SCC2698Block *blk0 = &dev->blk[block];
179     SCC2698Block *blk1 = &dev->blk[block^1];
180     unsigned intno = block / 2;
181 
182     if ((blk0->isr & blk0->imr) || (blk1->isr & blk1->imr)) {
183         qemu_irq_raise(idev->irq[intno]);
184     } else {
185         qemu_irq_lower(idev->irq[intno]);
186     }
187 }
188 
189 static void write_cr(IPOctalState *dev, unsigned channel, uint8_t val)
190 {
191     SCC2698Channel *ch = &dev->ch[channel];
192     SCC2698Block *blk = &dev->blk[channel / 2];
193 
194     DPRINTF("Write CR%c %u: ", channel + 'a', val);
195 
196     /* The lower 4 bits are used to enable and disable Tx and Rx */
197     if (val & CR_ENABLE_RX) {
198         DPRINTF2("Rx on, ");
199         ch->rx_enabled = true;
200     }
201     if (val & CR_DISABLE_RX) {
202         DPRINTF2("Rx off, ");
203         ch->rx_enabled = false;
204     }
205     if (val & CR_ENABLE_TX) {
206         DPRINTF2("Tx on, ");
207         ch->sr |= SR_TXRDY | SR_TXEMT;
208         blk->isr |= ISR_TXRDY(channel);
209     }
210     if (val & CR_DISABLE_TX) {
211         DPRINTF2("Tx off, ");
212         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
213         blk->isr &= ~ISR_TXRDY(channel);
214     }
215 
216     DPRINTF2("cmd: ");
217 
218     /* The rest of the bits implement different commands */
219     switch (CR_CMD(val)) {
220     case CR_NO_OP:
221         DPRINTF2("none");
222         break;
223     case CR_RESET_MR:
224         DPRINTF2("reset MR");
225         ch->mr_idx = 0;
226         break;
227     case CR_RESET_RX:
228         DPRINTF2("reset Rx");
229         ch->rx_enabled = false;
230         ch->rx_pending = 0;
231         ch->sr &= ~SR_RXRDY;
232         blk->isr &= ~ISR_RXRDY(channel);
233         break;
234     case CR_RESET_TX:
235         DPRINTF2("reset Tx");
236         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
237         blk->isr &= ~ISR_TXRDY(channel);
238         break;
239     case CR_RESET_ERR:
240         DPRINTF2("reset err");
241         ch->sr &= ~(SR_OVERRUN | SR_PARITY | SR_FRAMING | SR_BREAK);
242         break;
243     case CR_RESET_BRKINT:
244         DPRINTF2("reset brk ch int");
245         blk->isr &= ~(ISR_BREAKA | ISR_BREAKB);
246         break;
247     default:
248         DPRINTF2("unsupported 0x%x", CR_CMD(val));
249     }
250 
251     DPRINTF2("\n");
252 }
253 
254 static uint16_t io_read(IPackDevice *ip, uint8_t addr)
255 {
256     IPOctalState *dev = IPOCTAL(ip);
257     uint16_t ret = 0;
258     /* addr[7:6]: block   (A-D)
259        addr[7:5]: channel (a-h)
260        addr[5:0]: register */
261     unsigned block = addr >> 5;
262     unsigned channel = addr >> 4;
263     /* Big endian, accessed using 8-bit bytes at odd locations */
264     unsigned offset = (addr & 0x1F) ^ 1;
265     SCC2698Channel *ch = &dev->ch[channel];
266     SCC2698Block *blk = &dev->blk[block];
267     uint8_t old_isr = blk->isr;
268 
269     switch (offset) {
270 
271     case REG_MRa:
272     case REG_MRb:
273         ret = ch->mr[ch->mr_idx];
274         DPRINTF("Read MR%u%c: 0x%x\n", ch->mr_idx + 1, channel + 'a', ret);
275         ch->mr_idx = 1;
276         break;
277 
278     case REG_SRa:
279     case REG_SRb:
280         ret = ch->sr;
281         DPRINTF("Read SR%c: 0x%x\n", channel + 'a', ret);
282         break;
283 
284     case REG_RHRa:
285     case REG_RHRb:
286         ret = ch->rhr[ch->rhr_idx];
287         if (ch->rx_pending > 0) {
288             ch->rx_pending--;
289             if (ch->rx_pending == 0) {
290                 ch->sr &= ~SR_RXRDY;
291                 blk->isr &= ~ISR_RXRDY(channel);
292                 qemu_chr_fe_accept_input(&ch->dev);
293             } else {
294                 ch->rhr_idx = (ch->rhr_idx + 1) % RX_FIFO_SIZE;
295             }
296             if (ch->sr & SR_BREAK) {
297                 ch->sr &= ~SR_BREAK;
298                 blk->isr |= ISR_BREAK(channel);
299             }
300         }
301         DPRINTF("Read RHR%c (0x%x)\n", channel + 'a', ret);
302         break;
303 
304     case REG_ISR:
305         ret = blk->isr;
306         DPRINTF("Read ISR%c: 0x%x\n", block + 'A', ret);
307         break;
308 
309     default:
310         DPRINTF("Read unknown/unsupported register 0x%02x\n", offset);
311     }
312 
313     if (old_isr != blk->isr) {
314         update_irq(dev, block);
315     }
316 
317     return ret;
318 }
319 
320 static void io_write(IPackDevice *ip, uint8_t addr, uint16_t val)
321 {
322     IPOctalState *dev = IPOCTAL(ip);
323     unsigned reg = val & 0xFF;
324     /* addr[7:6]: block   (A-D)
325        addr[7:5]: channel (a-h)
326        addr[5:0]: register */
327     unsigned block = addr >> 5;
328     unsigned channel = addr >> 4;
329     /* Big endian, accessed using 8-bit bytes at odd locations */
330     unsigned offset = (addr & 0x1F) ^ 1;
331     SCC2698Channel *ch = &dev->ch[channel];
332     SCC2698Block *blk = &dev->blk[block];
333     uint8_t old_isr = blk->isr;
334     uint8_t old_imr = blk->imr;
335 
336     switch (offset) {
337 
338     case REG_MRa:
339     case REG_MRb:
340         ch->mr[ch->mr_idx] = reg;
341         DPRINTF("Write MR%u%c 0x%x\n", ch->mr_idx + 1, channel + 'a', reg);
342         ch->mr_idx = 1;
343         break;
344 
345     /* Not implemented */
346     case REG_CSRa:
347     case REG_CSRb:
348         DPRINTF("Write CSR%c: 0x%x\n", channel + 'a', reg);
349         break;
350 
351     case REG_CRa:
352     case REG_CRb:
353         write_cr(dev, channel, reg);
354         break;
355 
356     case REG_THRa:
357     case REG_THRb:
358         if (ch->sr & SR_TXRDY) {
359             uint8_t thr = reg;
360             DPRINTF("Write THR%c (0x%x)\n", channel + 'a', reg);
361             /* XXX this blocks entire thread. Rewrite to use
362              * qemu_chr_fe_write and background I/O callbacks */
363             qemu_chr_fe_write_all(&ch->dev, &thr, 1);
364         } else {
365             DPRINTF("Write THR%c (0x%x), Tx disabled\n", channel + 'a', reg);
366         }
367         break;
368 
369     /* Not implemented */
370     case REG_ACR:
371         DPRINTF("Write ACR%c 0x%x\n", block + 'A', val);
372         break;
373 
374     case REG_IMR:
375         DPRINTF("Write IMR%c 0x%x\n", block + 'A', val);
376         blk->imr = reg;
377         break;
378 
379     /* Not implemented */
380     case REG_OPCR:
381         DPRINTF("Write OPCR%c 0x%x\n", block + 'A', val);
382         break;
383 
384     default:
385         DPRINTF("Write unknown/unsupported register 0x%02x %u\n", offset, val);
386     }
387 
388     if (old_isr != blk->isr || old_imr != blk->imr) {
389         update_irq(dev, block);
390     }
391 }
392 
393 static uint16_t id_read(IPackDevice *ip, uint8_t addr)
394 {
395     uint16_t ret = 0;
396     unsigned pos = addr / 2; /* The ID PROM data is stored every other byte */
397 
398     if (pos < ARRAY_SIZE(id_prom_data)) {
399         ret = id_prom_data[pos];
400     } else {
401         DPRINTF("Attempt to read unavailable PROM data at 0x%x\n",  addr);
402     }
403 
404     return ret;
405 }
406 
407 static void id_write(IPackDevice *ip, uint8_t addr, uint16_t val)
408 {
409     IPOctalState *dev = IPOCTAL(ip);
410     if (addr == 1) {
411         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
412         dev->irq_vector = val; /* Undocumented, but the hw works like that */
413     } else {
414         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
415     }
416 }
417 
418 static uint16_t int_read(IPackDevice *ip, uint8_t addr)
419 {
420     IPOctalState *dev = IPOCTAL(ip);
421     /* Read address 0 to ACK INT0# and address 2 to ACK INT1# */
422     if (addr != 0 && addr != 2) {
423         DPRINTF("Attempt to read from 0x%x\n", addr);
424         return 0;
425     } else {
426         /* Update interrupts if necessary */
427         update_irq(dev, addr);
428         return dev->irq_vector;
429     }
430 }
431 
432 static void int_write(IPackDevice *ip, uint8_t addr, uint16_t val)
433 {
434     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
435 }
436 
437 static uint16_t mem_read16(IPackDevice *ip, uint32_t addr)
438 {
439     DPRINTF("Attempt to read from 0x%x\n", addr);
440     return 0;
441 }
442 
443 static void mem_write16(IPackDevice *ip, uint32_t addr, uint16_t val)
444 {
445     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
446 }
447 
448 static uint8_t mem_read8(IPackDevice *ip, uint32_t addr)
449 {
450     DPRINTF("Attempt to read from 0x%x\n", addr);
451     return 0;
452 }
453 
454 static void mem_write8(IPackDevice *ip, uint32_t addr, uint8_t val)
455 {
456     IPOctalState *dev = IPOCTAL(ip);
457     if (addr == 1) {
458         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
459         dev->irq_vector = val;
460     } else {
461         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
462     }
463 }
464 
465 static int hostdev_can_receive(void *opaque)
466 {
467     SCC2698Channel *ch = opaque;
468     int available_bytes = RX_FIFO_SIZE - ch->rx_pending;
469     return ch->rx_enabled ? available_bytes : 0;
470 }
471 
472 static void hostdev_receive(void *opaque, const uint8_t *buf, int size)
473 {
474     SCC2698Channel *ch = opaque;
475     IPOctalState *dev = ch->ipoctal;
476     unsigned pos = ch->rhr_idx + ch->rx_pending;
477     int i;
478 
479     assert(size + ch->rx_pending <= RX_FIFO_SIZE);
480 
481     /* Copy data to the RxFIFO */
482     for (i = 0; i < size; i++) {
483         pos %= RX_FIFO_SIZE;
484         ch->rhr[pos++] = buf[i];
485     }
486 
487     ch->rx_pending += size;
488 
489     /* If the RxFIFO was empty raise an interrupt */
490     if (!(ch->sr & SR_RXRDY)) {
491         unsigned block, channel = 0;
492         /* Find channel number to update the ISR register */
493         while (&dev->ch[channel] != ch) {
494             channel++;
495         }
496         block = channel / 2;
497         dev->blk[block].isr |= ISR_RXRDY(channel);
498         ch->sr |= SR_RXRDY;
499         update_irq(dev, block);
500     }
501 }
502 
503 static void hostdev_event(void *opaque, int event)
504 {
505     SCC2698Channel *ch = opaque;
506     switch (event) {
507     case CHR_EVENT_OPENED:
508         DPRINTF("Device %s opened\n", ch->dev->label);
509         break;
510     case CHR_EVENT_BREAK: {
511         uint8_t zero = 0;
512         DPRINTF("Device %s received break\n", ch->dev->label);
513 
514         if (!(ch->sr & SR_BREAK)) {
515             IPOctalState *dev = ch->ipoctal;
516             unsigned block, channel = 0;
517 
518             while (&dev->ch[channel] != ch) {
519                 channel++;
520             }
521             block = channel / 2;
522 
523             ch->sr |= SR_BREAK;
524             dev->blk[block].isr |= ISR_BREAK(channel);
525         }
526 
527         /* Put a zero character in the buffer */
528         hostdev_receive(ch, &zero, 1);
529     }
530         break;
531     default:
532         DPRINTF("Device %s received event %d\n", ch->dev->label, event);
533     }
534 }
535 
536 static void ipoctal_realize(DeviceState *dev, Error **errp)
537 {
538     IPOctalState *s = IPOCTAL(dev);
539     unsigned i;
540 
541     for (i = 0; i < N_CHANNELS; i++) {
542         SCC2698Channel *ch = &s->ch[i];
543         ch->ipoctal = s;
544 
545         /* Redirect IP-Octal channels to host character devices */
546         if (qemu_chr_fe_backend_connected(&ch->dev)) {
547             qemu_chr_fe_set_handlers(&ch->dev, hostdev_can_receive,
548                                      hostdev_receive, hostdev_event,
549                                      NULL, ch, NULL, true);
550             DPRINTF("Redirecting channel %u to %s\n", i, ch->dev->label);
551         } else {
552             DPRINTF("Could not redirect channel %u, no chardev set\n", i);
553         }
554     }
555 }
556 
557 static Property ipoctal_properties[] = {
558     DEFINE_PROP_CHR("chardev0", IPOctalState, ch[0].dev),
559     DEFINE_PROP_CHR("chardev1", IPOctalState, ch[1].dev),
560     DEFINE_PROP_CHR("chardev2", IPOctalState, ch[2].dev),
561     DEFINE_PROP_CHR("chardev3", IPOctalState, ch[3].dev),
562     DEFINE_PROP_CHR("chardev4", IPOctalState, ch[4].dev),
563     DEFINE_PROP_CHR("chardev5", IPOctalState, ch[5].dev),
564     DEFINE_PROP_CHR("chardev6", IPOctalState, ch[6].dev),
565     DEFINE_PROP_CHR("chardev7", IPOctalState, ch[7].dev),
566     DEFINE_PROP_END_OF_LIST(),
567 };
568 
569 static void ipoctal_class_init(ObjectClass *klass, void *data)
570 {
571     DeviceClass *dc = DEVICE_CLASS(klass);
572     IPackDeviceClass *ic = IPACK_DEVICE_CLASS(klass);
573 
574     ic->realize     = ipoctal_realize;
575     ic->io_read     = io_read;
576     ic->io_write    = io_write;
577     ic->id_read     = id_read;
578     ic->id_write    = id_write;
579     ic->int_read    = int_read;
580     ic->int_write   = int_write;
581     ic->mem_read16  = mem_read16;
582     ic->mem_write16 = mem_write16;
583     ic->mem_read8   = mem_read8;
584     ic->mem_write8  = mem_write8;
585 
586     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
587     dc->desc    = "GE IP-Octal 232 8-channel RS-232 IndustryPack";
588     dc->props   = ipoctal_properties;
589     dc->vmsd    = &vmstate_ipoctal;
590 }
591 
592 static const TypeInfo ipoctal_info = {
593     .name          = TYPE_IPOCTAL,
594     .parent        = TYPE_IPACK_DEVICE,
595     .instance_size = sizeof(IPOctalState),
596     .class_init    = ipoctal_class_init,
597 };
598 
599 static void ipoctal_register_types(void)
600 {
601     type_register_static(&ipoctal_info);
602 }
603 
604 type_init(ipoctal_register_types)
605