xref: /openbmc/qemu/hw/char/ipoctal232.c (revision c16de0d9)
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 "hw/qdev-properties-system.h"
16 #include "migration/vmstate.h"
17 #include "qemu/bitops.h"
18 #include "qemu/module.h"
19 #include "chardev/char-fe.h"
20 #include "qom/object.h"
21 
22 /* #define DEBUG_IPOCTAL */
23 
24 #ifdef DEBUG_IPOCTAL
25 #define DPRINTF2(fmt, ...) \
26     do { fprintf(stderr, fmt, ## __VA_ARGS__); } while (0)
27 #else
28 #define DPRINTF2(fmt, ...) do { } while (0)
29 #endif
30 
31 #define DPRINTF(fmt, ...) DPRINTF2("IP-Octal: " fmt, ## __VA_ARGS__)
32 
33 #define RX_FIFO_SIZE 3
34 
35 /* The IP-Octal has 8 channels (a-h)
36    divided into 4 blocks (A-D) */
37 #define N_CHANNELS 8
38 #define N_BLOCKS   4
39 
40 #define REG_MRa  0x01
41 #define REG_MRb  0x11
42 #define REG_SRa  0x03
43 #define REG_SRb  0x13
44 #define REG_CSRa 0x03
45 #define REG_CSRb 0x13
46 #define REG_CRa  0x05
47 #define REG_CRb  0x15
48 #define REG_RHRa 0x07
49 #define REG_RHRb 0x17
50 #define REG_THRa 0x07
51 #define REG_THRb 0x17
52 #define REG_ACR  0x09
53 #define REG_ISR  0x0B
54 #define REG_IMR  0x0B
55 #define REG_OPCR 0x1B
56 
57 #define CR_ENABLE_RX    BIT(0)
58 #define CR_DISABLE_RX   BIT(1)
59 #define CR_ENABLE_TX    BIT(2)
60 #define CR_DISABLE_TX   BIT(3)
61 #define CR_CMD(cr)      ((cr) >> 4)
62 #define CR_NO_OP        0
63 #define CR_RESET_MR     1
64 #define CR_RESET_RX     2
65 #define CR_RESET_TX     3
66 #define CR_RESET_ERR    4
67 #define CR_RESET_BRKINT 5
68 #define CR_START_BRK    6
69 #define CR_STOP_BRK     7
70 #define CR_ASSERT_RTSN  8
71 #define CR_NEGATE_RTSN  9
72 #define CR_TIMEOUT_ON   10
73 #define CR_TIMEOUT_OFF  12
74 
75 #define SR_RXRDY   BIT(0)
76 #define SR_FFULL   BIT(1)
77 #define SR_TXRDY   BIT(2)
78 #define SR_TXEMT   BIT(3)
79 #define SR_OVERRUN BIT(4)
80 #define SR_PARITY  BIT(5)
81 #define SR_FRAMING BIT(6)
82 #define SR_BREAK   BIT(7)
83 
84 #define ISR_TXRDYA BIT(0)
85 #define ISR_RXRDYA BIT(1)
86 #define ISR_BREAKA BIT(2)
87 #define ISR_CNTRDY BIT(3)
88 #define ISR_TXRDYB BIT(4)
89 #define ISR_RXRDYB BIT(5)
90 #define ISR_BREAKB BIT(6)
91 #define ISR_MPICHG BIT(7)
92 #define ISR_TXRDY(CH) (((CH) & 1) ? BIT(4) : BIT(0))
93 #define ISR_RXRDY(CH) (((CH) & 1) ? BIT(5) : BIT(1))
94 #define ISR_BREAK(CH) (((CH) & 1) ? BIT(6) : BIT(2))
95 
96 typedef struct IPOctalState IPOctalState;
97 typedef struct SCC2698Channel SCC2698Channel;
98 typedef struct SCC2698Block SCC2698Block;
99 
100 struct SCC2698Channel {
101     IPOctalState *ipoctal;
102     CharBackend dev;
103     bool rx_enabled;
104     uint8_t mr[2];
105     uint8_t mr_idx;
106     uint8_t sr;
107     uint8_t rhr[RX_FIFO_SIZE];
108     uint8_t rhr_idx;
109     uint8_t rx_pending;
110 };
111 
112 struct SCC2698Block {
113     uint8_t imr;
114     uint8_t isr;
115 };
116 
117 struct IPOctalState {
118     IPackDevice parent_obj;
119 
120     SCC2698Channel ch[N_CHANNELS];
121     SCC2698Block blk[N_BLOCKS];
122     uint8_t irq_vector;
123 };
124 
125 #define TYPE_IPOCTAL "ipoctal232"
126 
127 OBJECT_DECLARE_SIMPLE_TYPE(IPOctalState, IPOCTAL)
128 
129 static const VMStateDescription vmstate_scc2698_channel = {
130     .name = "scc2698_channel",
131     .version_id = 1,
132     .minimum_version_id = 1,
133     .fields = (const VMStateField[]) {
134         VMSTATE_BOOL(rx_enabled, SCC2698Channel),
135         VMSTATE_UINT8_ARRAY(mr, SCC2698Channel, 2),
136         VMSTATE_UINT8(mr_idx, SCC2698Channel),
137         VMSTATE_UINT8(sr, SCC2698Channel),
138         VMSTATE_UINT8_ARRAY(rhr, SCC2698Channel, RX_FIFO_SIZE),
139         VMSTATE_UINT8(rhr_idx, SCC2698Channel),
140         VMSTATE_UINT8(rx_pending, SCC2698Channel),
141         VMSTATE_END_OF_LIST()
142     }
143 };
144 
145 static const VMStateDescription vmstate_scc2698_block = {
146     .name = "scc2698_block",
147     .version_id = 1,
148     .minimum_version_id = 1,
149     .fields = (const VMStateField[]) {
150         VMSTATE_UINT8(imr, SCC2698Block),
151         VMSTATE_UINT8(isr, SCC2698Block),
152         VMSTATE_END_OF_LIST()
153     }
154 };
155 
156 static const VMStateDescription vmstate_ipoctal = {
157     .name = "ipoctal232",
158     .version_id = 1,
159     .minimum_version_id = 1,
160     .fields = (const VMStateField[]) {
161         VMSTATE_IPACK_DEVICE(parent_obj, IPOctalState),
162         VMSTATE_STRUCT_ARRAY(ch, IPOctalState, N_CHANNELS, 1,
163                              vmstate_scc2698_channel, SCC2698Channel),
164         VMSTATE_STRUCT_ARRAY(blk, IPOctalState, N_BLOCKS, 1,
165                              vmstate_scc2698_block, SCC2698Block),
166         VMSTATE_UINT8(irq_vector, IPOctalState),
167         VMSTATE_END_OF_LIST()
168     }
169 };
170 
171 /* data[10] is 0x0C, not 0x0B as the doc says */
172 static const uint8_t id_prom_data[] = {
173     0x49, 0x50, 0x41, 0x43, 0xF0, 0x22,
174     0xA1, 0x00, 0x00, 0x00, 0x0C, 0xCC
175 };
176 
177 static void update_irq(IPOctalState *dev, unsigned block)
178 {
179     IPackDevice *idev = IPACK_DEVICE(dev);
180     /* Blocks A and B interrupt on INT0#, C and D on INT1#.
181        Thus, to get the status we have to check two blocks. */
182     SCC2698Block *blk0 = &dev->blk[block];
183     SCC2698Block *blk1 = &dev->blk[block^1];
184     unsigned intno = block / 2;
185 
186     if ((blk0->isr & blk0->imr) || (blk1->isr & blk1->imr)) {
187         qemu_irq_raise(idev->irq[intno]);
188     } else {
189         qemu_irq_lower(idev->irq[intno]);
190     }
191 }
192 
193 static void write_cr(IPOctalState *dev, unsigned channel, uint8_t val)
194 {
195     SCC2698Channel *ch = &dev->ch[channel];
196     SCC2698Block *blk = &dev->blk[channel / 2];
197 
198     DPRINTF("Write CR%c %u: ", channel + 'a', val);
199 
200     /* The lower 4 bits are used to enable and disable Tx and Rx */
201     if (val & CR_ENABLE_RX) {
202         DPRINTF2("Rx on, ");
203         ch->rx_enabled = true;
204     }
205     if (val & CR_DISABLE_RX) {
206         DPRINTF2("Rx off, ");
207         ch->rx_enabled = false;
208     }
209     if (val & CR_ENABLE_TX) {
210         DPRINTF2("Tx on, ");
211         ch->sr |= SR_TXRDY | SR_TXEMT;
212         blk->isr |= ISR_TXRDY(channel);
213     }
214     if (val & CR_DISABLE_TX) {
215         DPRINTF2("Tx off, ");
216         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
217         blk->isr &= ~ISR_TXRDY(channel);
218     }
219 
220     DPRINTF2("cmd: ");
221 
222     /* The rest of the bits implement different commands */
223     switch (CR_CMD(val)) {
224     case CR_NO_OP:
225         DPRINTF2("none");
226         break;
227     case CR_RESET_MR:
228         DPRINTF2("reset MR");
229         ch->mr_idx = 0;
230         break;
231     case CR_RESET_RX:
232         DPRINTF2("reset Rx");
233         ch->rx_enabled = false;
234         ch->rx_pending = 0;
235         ch->sr &= ~SR_RXRDY;
236         blk->isr &= ~ISR_RXRDY(channel);
237         break;
238     case CR_RESET_TX:
239         DPRINTF2("reset Tx");
240         ch->sr &= ~(SR_TXRDY | SR_TXEMT);
241         blk->isr &= ~ISR_TXRDY(channel);
242         break;
243     case CR_RESET_ERR:
244         DPRINTF2("reset err");
245         ch->sr &= ~(SR_OVERRUN | SR_PARITY | SR_FRAMING | SR_BREAK);
246         break;
247     case CR_RESET_BRKINT:
248         DPRINTF2("reset brk ch int");
249         blk->isr &= ~(ISR_BREAKA | ISR_BREAKB);
250         break;
251     default:
252         DPRINTF2("unsupported 0x%x", CR_CMD(val));
253     }
254 
255     DPRINTF2("\n");
256 }
257 
258 static uint16_t io_read(IPackDevice *ip, uint8_t addr)
259 {
260     IPOctalState *dev = IPOCTAL(ip);
261     uint16_t ret = 0;
262     /* addr[7:6]: block   (A-D)
263        addr[7:5]: channel (a-h)
264        addr[5:0]: register */
265     unsigned block = addr >> 5;
266     unsigned channel = addr >> 4;
267     /* Big endian, accessed using 8-bit bytes at odd locations */
268     unsigned offset = (addr & 0x1F) ^ 1;
269     SCC2698Channel *ch = &dev->ch[channel];
270     SCC2698Block *blk = &dev->blk[block];
271     uint8_t old_isr = blk->isr;
272 
273     switch (offset) {
274 
275     case REG_MRa:
276     case REG_MRb:
277         ret = ch->mr[ch->mr_idx];
278         DPRINTF("Read MR%u%c: 0x%x\n", ch->mr_idx + 1, channel + 'a', ret);
279         ch->mr_idx = 1;
280         break;
281 
282     case REG_SRa:
283     case REG_SRb:
284         ret = ch->sr;
285         DPRINTF("Read SR%c: 0x%x\n", channel + 'a', ret);
286         break;
287 
288     case REG_RHRa:
289     case REG_RHRb:
290         ret = ch->rhr[ch->rhr_idx];
291         if (ch->rx_pending > 0) {
292             ch->rx_pending--;
293             if (ch->rx_pending == 0) {
294                 ch->sr &= ~SR_RXRDY;
295                 blk->isr &= ~ISR_RXRDY(channel);
296                 qemu_chr_fe_accept_input(&ch->dev);
297             } else {
298                 ch->rhr_idx = (ch->rhr_idx + 1) % RX_FIFO_SIZE;
299             }
300             if (ch->sr & SR_BREAK) {
301                 ch->sr &= ~SR_BREAK;
302                 blk->isr |= ISR_BREAK(channel);
303             }
304         }
305         DPRINTF("Read RHR%c (0x%x)\n", channel + 'a', ret);
306         break;
307 
308     case REG_ISR:
309         ret = blk->isr;
310         DPRINTF("Read ISR%c: 0x%x\n", block + 'A', ret);
311         break;
312 
313     default:
314         DPRINTF("Read unknown/unsupported register 0x%02x\n", offset);
315     }
316 
317     if (old_isr != blk->isr) {
318         update_irq(dev, block);
319     }
320 
321     return ret;
322 }
323 
324 static void io_write(IPackDevice *ip, uint8_t addr, uint16_t val)
325 {
326     IPOctalState *dev = IPOCTAL(ip);
327     unsigned reg = val & 0xFF;
328     /* addr[7:6]: block   (A-D)
329        addr[7:5]: channel (a-h)
330        addr[5:0]: register */
331     unsigned block = addr >> 5;
332     unsigned channel = addr >> 4;
333     /* Big endian, accessed using 8-bit bytes at odd locations */
334     unsigned offset = (addr & 0x1F) ^ 1;
335     SCC2698Channel *ch = &dev->ch[channel];
336     SCC2698Block *blk = &dev->blk[block];
337     uint8_t old_isr = blk->isr;
338     uint8_t old_imr = blk->imr;
339 
340     switch (offset) {
341 
342     case REG_MRa:
343     case REG_MRb:
344         ch->mr[ch->mr_idx] = reg;
345         DPRINTF("Write MR%u%c 0x%x\n", ch->mr_idx + 1, channel + 'a', reg);
346         ch->mr_idx = 1;
347         break;
348 
349     /* Not implemented */
350     case REG_CSRa:
351     case REG_CSRb:
352         DPRINTF("Write CSR%c: 0x%x\n", channel + 'a', reg);
353         break;
354 
355     case REG_CRa:
356     case REG_CRb:
357         write_cr(dev, channel, reg);
358         break;
359 
360     case REG_THRa:
361     case REG_THRb:
362         if (ch->sr & SR_TXRDY) {
363             uint8_t thr = reg;
364             DPRINTF("Write THR%c (0x%x)\n", channel + 'a', reg);
365             /* XXX this blocks entire thread. Rewrite to use
366              * qemu_chr_fe_write and background I/O callbacks */
367             qemu_chr_fe_write_all(&ch->dev, &thr, 1);
368         } else {
369             DPRINTF("Write THR%c (0x%x), Tx disabled\n", channel + 'a', reg);
370         }
371         break;
372 
373     /* Not implemented */
374     case REG_ACR:
375         DPRINTF("Write ACR%c 0x%x\n", block + 'A', val);
376         break;
377 
378     case REG_IMR:
379         DPRINTF("Write IMR%c 0x%x\n", block + 'A', val);
380         blk->imr = reg;
381         break;
382 
383     /* Not implemented */
384     case REG_OPCR:
385         DPRINTF("Write OPCR%c 0x%x\n", block + 'A', val);
386         break;
387 
388     default:
389         DPRINTF("Write unknown/unsupported register 0x%02x %u\n", offset, val);
390     }
391 
392     if (old_isr != blk->isr || old_imr != blk->imr) {
393         update_irq(dev, block);
394     }
395 }
396 
397 static uint16_t id_read(IPackDevice *ip, uint8_t addr)
398 {
399     uint16_t ret = 0;
400     unsigned pos = addr / 2; /* The ID PROM data is stored every other byte */
401 
402     if (pos < ARRAY_SIZE(id_prom_data)) {
403         ret = id_prom_data[pos];
404     } else {
405         DPRINTF("Attempt to read unavailable PROM data at 0x%x\n",  addr);
406     }
407 
408     return ret;
409 }
410 
411 static void id_write(IPackDevice *ip, uint8_t addr, uint16_t val)
412 {
413     IPOctalState *dev = IPOCTAL(ip);
414     if (addr == 1) {
415         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
416         dev->irq_vector = val; /* Undocumented, but the hw works like that */
417     } else {
418         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
419     }
420 }
421 
422 static uint16_t int_read(IPackDevice *ip, uint8_t addr)
423 {
424     IPOctalState *dev = IPOCTAL(ip);
425     /* Read address 0 to ACK INT0# and address 2 to ACK INT1# */
426     if (addr != 0 && addr != 2) {
427         DPRINTF("Attempt to read from 0x%x\n", addr);
428         return 0;
429     } else {
430         /* Update interrupts if necessary */
431         update_irq(dev, addr);
432         return dev->irq_vector;
433     }
434 }
435 
436 static void int_write(IPackDevice *ip, uint8_t addr, uint16_t val)
437 {
438     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
439 }
440 
441 static uint16_t mem_read16(IPackDevice *ip, uint32_t addr)
442 {
443     DPRINTF("Attempt to read from 0x%x\n", addr);
444     return 0;
445 }
446 
447 static void mem_write16(IPackDevice *ip, uint32_t addr, uint16_t val)
448 {
449     DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
450 }
451 
452 static uint8_t mem_read8(IPackDevice *ip, uint32_t addr)
453 {
454     DPRINTF("Attempt to read from 0x%x\n", addr);
455     return 0;
456 }
457 
458 static void mem_write8(IPackDevice *ip, uint32_t addr, uint8_t val)
459 {
460     IPOctalState *dev = IPOCTAL(ip);
461     if (addr == 1) {
462         DPRINTF("Write IRQ vector: %u\n", (unsigned) val);
463         dev->irq_vector = val;
464     } else {
465         DPRINTF("Attempt to write 0x%x to 0x%x\n", val, addr);
466     }
467 }
468 
469 static int hostdev_can_receive(void *opaque)
470 {
471     SCC2698Channel *ch = opaque;
472     int available_bytes = RX_FIFO_SIZE - ch->rx_pending;
473     return ch->rx_enabled ? available_bytes : 0;
474 }
475 
476 static void hostdev_receive(void *opaque, const uint8_t *buf, int size)
477 {
478     SCC2698Channel *ch = opaque;
479     IPOctalState *dev = ch->ipoctal;
480     unsigned pos = ch->rhr_idx + ch->rx_pending;
481     int i;
482 
483     assert(size + ch->rx_pending <= RX_FIFO_SIZE);
484 
485     /* Copy data to the RxFIFO */
486     for (i = 0; i < size; i++) {
487         pos %= RX_FIFO_SIZE;
488         ch->rhr[pos++] = buf[i];
489     }
490 
491     ch->rx_pending += size;
492 
493     /* If the RxFIFO was empty raise an interrupt */
494     if (!(ch->sr & SR_RXRDY)) {
495         unsigned block, channel = 0;
496         /* Find channel number to update the ISR register */
497         while (&dev->ch[channel] != ch) {
498             channel++;
499         }
500         block = channel / 2;
501         dev->blk[block].isr |= ISR_RXRDY(channel);
502         ch->sr |= SR_RXRDY;
503         update_irq(dev, block);
504     }
505 }
506 
507 static void hostdev_event(void *opaque, QEMUChrEvent event)
508 {
509     SCC2698Channel *ch = opaque;
510     switch (event) {
511     case CHR_EVENT_OPENED:
512         DPRINTF("Device %s opened\n", ch->dev->label);
513         break;
514     case CHR_EVENT_BREAK: {
515         uint8_t zero = 0;
516         DPRINTF("Device %s received break\n", ch->dev->label);
517 
518         if (!(ch->sr & SR_BREAK)) {
519             IPOctalState *dev = ch->ipoctal;
520             unsigned block, channel = 0;
521 
522             while (&dev->ch[channel] != ch) {
523                 channel++;
524             }
525             block = channel / 2;
526 
527             ch->sr |= SR_BREAK;
528             dev->blk[block].isr |= ISR_BREAK(channel);
529         }
530 
531         /* Put a zero character in the buffer */
532         hostdev_receive(ch, &zero, 1);
533     }
534         break;
535     default:
536         DPRINTF("Device %s received event %d\n", ch->dev->label, event);
537     }
538 }
539 
540 static void ipoctal_realize(DeviceState *dev, Error **errp)
541 {
542     IPOctalState *s = IPOCTAL(dev);
543     unsigned i;
544 
545     for (i = 0; i < N_CHANNELS; i++) {
546         SCC2698Channel *ch = &s->ch[i];
547         ch->ipoctal = s;
548 
549         /* Redirect IP-Octal channels to host character devices */
550         if (qemu_chr_fe_backend_connected(&ch->dev)) {
551             qemu_chr_fe_set_handlers(&ch->dev, hostdev_can_receive,
552                                      hostdev_receive, hostdev_event,
553                                      NULL, ch, NULL, true);
554             DPRINTF("Redirecting channel %u to %s\n", i, ch->dev->label);
555         } else {
556             DPRINTF("Could not redirect channel %u, no chardev set\n", i);
557         }
558     }
559 }
560 
561 static Property ipoctal_properties[] = {
562     DEFINE_PROP_CHR("chardev0", IPOctalState, ch[0].dev),
563     DEFINE_PROP_CHR("chardev1", IPOctalState, ch[1].dev),
564     DEFINE_PROP_CHR("chardev2", IPOctalState, ch[2].dev),
565     DEFINE_PROP_CHR("chardev3", IPOctalState, ch[3].dev),
566     DEFINE_PROP_CHR("chardev4", IPOctalState, ch[4].dev),
567     DEFINE_PROP_CHR("chardev5", IPOctalState, ch[5].dev),
568     DEFINE_PROP_CHR("chardev6", IPOctalState, ch[6].dev),
569     DEFINE_PROP_CHR("chardev7", IPOctalState, ch[7].dev),
570     DEFINE_PROP_END_OF_LIST(),
571 };
572 
573 static void ipoctal_class_init(ObjectClass *klass, void *data)
574 {
575     DeviceClass *dc = DEVICE_CLASS(klass);
576     IPackDeviceClass *ic = IPACK_DEVICE_CLASS(klass);
577 
578     ic->realize     = ipoctal_realize;
579     ic->io_read     = io_read;
580     ic->io_write    = io_write;
581     ic->id_read     = id_read;
582     ic->id_write    = id_write;
583     ic->int_read    = int_read;
584     ic->int_write   = int_write;
585     ic->mem_read16  = mem_read16;
586     ic->mem_write16 = mem_write16;
587     ic->mem_read8   = mem_read8;
588     ic->mem_write8  = mem_write8;
589 
590     set_bit(DEVICE_CATEGORY_INPUT, dc->categories);
591     dc->desc    = "GE IP-Octal 232 8-channel RS-232 IndustryPack";
592     device_class_set_props(dc, ipoctal_properties);
593     dc->vmsd    = &vmstate_ipoctal;
594 }
595 
596 static const TypeInfo ipoctal_info = {
597     .name          = TYPE_IPOCTAL,
598     .parent        = TYPE_IPACK_DEVICE,
599     .instance_size = sizeof(IPOctalState),
600     .class_init    = ipoctal_class_init,
601 };
602 
603 static void ipoctal_register_types(void)
604 {
605     type_register_static(&ipoctal_info);
606 }
607 
608 type_init(ipoctal_register_types)
609