xref: /qemu/hw/misc/mips_itu.c (revision abff1abf) 
1 /*
2  * Inter-Thread Communication Unit emulation.
3  *
4  * Copyright (c) 2016 Imagination Technologies
5  *
6  * This library is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU Lesser General Public
8  * License as published by the Free Software Foundation; either
9  * version 2 of the License, or (at your option) any later version.
10  *
11  * This library is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14  * Lesser General Public License for more details.
15  *
16  * You should have received a copy of the GNU Lesser General Public
17  * License along with this library; if not, see <http://www.gnu.org/licenses/>.
18  */
19 
20 #include "qemu/osdep.h"
21 #include "qemu/units.h"
22 #include "qemu/log.h"
23 #include "qemu/module.h"
24 #include "qapi/error.h"
25 #include "cpu.h"
26 #include "exec/exec-all.h"
27 #include "hw/misc/mips_itu.h"
28 #include "hw/qdev-properties.h"
29 
30 #define ITC_TAG_ADDRSPACE_SZ (ITC_ADDRESSMAP_NUM * 8)
31 /* Initialize as 4kB area to fit all 32 cells with default 128B grain.
32    Storage may be resized by the software. */
33 #define ITC_STORAGE_ADDRSPACE_SZ 0x1000
34 
35 #define ITC_FIFO_NUM_MAX 16
36 #define ITC_SEMAPH_NUM_MAX 16
37 #define ITC_AM1_NUMENTRIES_OFS 20
38 
39 #define ITC_CELL_PV_MAX_VAL 0xFFFF
40 
41 #define ITC_CELL_TAG_FIFO_DEPTH 28
42 #define ITC_CELL_TAG_FIFO_PTR 18
43 #define ITC_CELL_TAG_FIFO 17
44 #define ITC_CELL_TAG_T 16
45 #define ITC_CELL_TAG_F 1
46 #define ITC_CELL_TAG_E 0
47 
48 #define ITC_AM0_BASE_ADDRESS_MASK 0xFFFFFC00ULL
49 #define ITC_AM0_EN_MASK 0x1
50 
51 #define ITC_AM1_ADDR_MASK_MASK 0x1FC00
52 #define ITC_AM1_ENTRY_GRAIN_MASK 0x7
53 
54 typedef enum ITCView {
55     ITCVIEW_BYPASS  = 0,
56     ITCVIEW_CONTROL = 1,
57     ITCVIEW_EF_SYNC = 2,
58     ITCVIEW_EF_TRY  = 3,
59     ITCVIEW_PV_SYNC = 4,
60     ITCVIEW_PV_TRY  = 5,
61     ITCVIEW_PV_ICR0 = 15,
62 } ITCView;
63 
64 #define ITC_ICR0_CELL_NUM        16
65 #define ITC_ICR0_BLK_GRAIN       8
66 #define ITC_ICR0_BLK_GRAIN_MASK  0x7
67 #define ITC_ICR0_ERR_AXI         2
68 #define ITC_ICR0_ERR_PARITY      1
69 #define ITC_ICR0_ERR_EXEC        0
70 
71 MemoryRegion *mips_itu_get_tag_region(MIPSITUState *itu)
72 {
73     return &itu->tag_io;
74 }
75 
76 static uint64_t itc_tag_read(void *opaque, hwaddr addr, unsigned size)
77 {
78     MIPSITUState *tag = (MIPSITUState *)opaque;
79     uint64_t index = addr >> 3;
80 
81     if (index >= ITC_ADDRESSMAP_NUM) {
82         qemu_log_mask(LOG_GUEST_ERROR, "Read 0x%" PRIx64 "\n", addr);
83         return 0;
84     }
85 
86     return tag->ITCAddressMap[index];
87 }
88 
89 void itc_reconfigure(MIPSITUState *tag)
90 {
91     uint64_t *am = &tag->ITCAddressMap[0];
92     MemoryRegion *mr = &tag->storage_io;
93     hwaddr address = am[0] & ITC_AM0_BASE_ADDRESS_MASK;
94     uint64_t size = (1 * KiB) + (am[1] & ITC_AM1_ADDR_MASK_MASK);
95     bool is_enabled = (am[0] & ITC_AM0_EN_MASK) != 0;
96 
97     if (tag->saar_present) {
98         address = ((*(uint64_t *) tag->saar) & 0xFFFFFFFFE000ULL) << 4;
99         size = 1ULL << ((*(uint64_t *) tag->saar >> 1) & 0x1f);
100         is_enabled = *(uint64_t *) tag->saar & 1;
101     }
102 
103     memory_region_transaction_begin();
104     if (!(size & (size - 1))) {
105         memory_region_set_size(mr, size);
106     }
107     memory_region_set_address(mr, address);
108     memory_region_set_enabled(mr, is_enabled);
109     memory_region_transaction_commit();
110 }
111 
112 static void itc_tag_write(void *opaque, hwaddr addr,
113                           uint64_t data, unsigned size)
114 {
115     MIPSITUState *tag = (MIPSITUState *)opaque;
116     uint64_t *am = &tag->ITCAddressMap[0];
117     uint64_t am_old, mask;
118     uint64_t index = addr >> 3;
119 
120     switch (index) {
121     case 0:
122         mask = ITC_AM0_BASE_ADDRESS_MASK | ITC_AM0_EN_MASK;
123         break;
124     case 1:
125         mask = ITC_AM1_ADDR_MASK_MASK | ITC_AM1_ENTRY_GRAIN_MASK;
126         break;
127     default:
128         qemu_log_mask(LOG_GUEST_ERROR, "Bad write 0x%" PRIx64 "\n", addr);
129         return;
130     }
131 
132     am_old = am[index];
133     am[index] = (data & mask) | (am_old & ~mask);
134     if (am_old != am[index]) {
135         itc_reconfigure(tag);
136     }
137 }
138 
139 static const MemoryRegionOps itc_tag_ops = {
140     .read = itc_tag_read,
141     .write = itc_tag_write,
142     .impl = {
143         .max_access_size = 8,
144     },
145     .endianness = DEVICE_NATIVE_ENDIAN,
146 };
147 
148 static inline uint32_t get_num_cells(MIPSITUState *s)
149 {
150     return s->num_fifo + s->num_semaphores;
151 }
152 
153 static inline ITCView get_itc_view(hwaddr addr)
154 {
155     return (addr >> 3) & 0xf;
156 }
157 
158 static inline int get_cell_stride_shift(const MIPSITUState *s)
159 {
160     /* Minimum interval (for EntryGain = 0) is 128 B */
161     if (s->saar_present) {
162         return 7 + ((s->icr0 >> ITC_ICR0_BLK_GRAIN) &
163                     ITC_ICR0_BLK_GRAIN_MASK);
164     } else {
165         return 7 + (s->ITCAddressMap[1] & ITC_AM1_ENTRY_GRAIN_MASK);
166     }
167 }
168 
169 static inline ITCStorageCell *get_cell(MIPSITUState *s,
170                                        hwaddr addr)
171 {
172     uint32_t cell_idx = addr >> get_cell_stride_shift(s);
173     uint32_t num_cells = get_num_cells(s);
174 
175     if (cell_idx >= num_cells) {
176         cell_idx = num_cells - 1;
177     }
178 
179     return &s->cell[cell_idx];
180 }
181 
182 static void wake_blocked_threads(ITCStorageCell *c)
183 {
184     CPUState *cs;
185     CPU_FOREACH(cs) {
186         if (cs->halted && (c->blocked_threads & (1ULL << cs->cpu_index))) {
187             cpu_interrupt(cs, CPU_INTERRUPT_WAKE);
188         }
189     }
190     c->blocked_threads = 0;
191 }
192 
193 static void QEMU_NORETURN block_thread_and_exit(ITCStorageCell *c)
194 {
195     c->blocked_threads |= 1ULL << current_cpu->cpu_index;
196     current_cpu->halted = 1;
197     current_cpu->exception_index = EXCP_HLT;
198     cpu_loop_exit_restore(current_cpu, current_cpu->mem_io_pc);
199 }
200 
201 /* ITC Bypass View */
202 
203 static inline uint64_t view_bypass_read(ITCStorageCell *c)
204 {
205     if (c->tag.FIFO) {
206         return c->data[c->fifo_out];
207     } else {
208         return c->data[0];
209     }
210 }
211 
212 static inline void view_bypass_write(ITCStorageCell *c, uint64_t val)
213 {
214     if (c->tag.FIFO && (c->tag.FIFOPtr > 0)) {
215         int idx = (c->fifo_out + c->tag.FIFOPtr - 1) % ITC_CELL_DEPTH;
216         c->data[idx] = val;
217     }
218 
219     /* ignore a write to the semaphore cell */
220 }
221 
222 /* ITC Control View */
223 
224 static inline uint64_t view_control_read(ITCStorageCell *c)
225 {
226     return ((uint64_t)c->tag.FIFODepth << ITC_CELL_TAG_FIFO_DEPTH) |
227            (c->tag.FIFOPtr << ITC_CELL_TAG_FIFO_PTR) |
228            (c->tag.FIFO << ITC_CELL_TAG_FIFO) |
229            (c->tag.T << ITC_CELL_TAG_T) |
230            (c->tag.E << ITC_CELL_TAG_E) |
231            (c->tag.F << ITC_CELL_TAG_F);
232 }
233 
234 static inline void view_control_write(ITCStorageCell *c, uint64_t val)
235 {
236     c->tag.T = (val >> ITC_CELL_TAG_T) & 1;
237     c->tag.E = (val >> ITC_CELL_TAG_E) & 1;
238     c->tag.F = (val >> ITC_CELL_TAG_F) & 1;
239 
240     if (c->tag.E) {
241         c->tag.FIFOPtr = 0;
242     }
243 }
244 
245 /* ITC Empty/Full View */
246 
247 static uint64_t view_ef_common_read(ITCStorageCell *c, bool blocking)
248 {
249     uint64_t ret = 0;
250 
251     if (!c->tag.FIFO) {
252         return 0;
253     }
254 
255     c->tag.F = 0;
256 
257     if (blocking && c->tag.E) {
258         block_thread_and_exit(c);
259     }
260 
261     if (c->blocked_threads) {
262         wake_blocked_threads(c);
263     }
264 
265     if (c->tag.FIFOPtr > 0) {
266         ret = c->data[c->fifo_out];
267         c->fifo_out = (c->fifo_out + 1) % ITC_CELL_DEPTH;
268         c->tag.FIFOPtr--;
269     }
270 
271     if (c->tag.FIFOPtr == 0) {
272         c->tag.E = 1;
273     }
274 
275     return ret;
276 }
277 
278 static uint64_t view_ef_sync_read(ITCStorageCell *c)
279 {
280     return view_ef_common_read(c, true);
281 }
282 
283 static uint64_t view_ef_try_read(ITCStorageCell *c)
284 {
285     return view_ef_common_read(c, false);
286 }
287 
288 static inline void view_ef_common_write(ITCStorageCell *c, uint64_t val,
289                                         bool blocking)
290 {
291     if (!c->tag.FIFO) {
292         return;
293     }
294 
295     c->tag.E = 0;
296 
297     if (blocking && c->tag.F) {
298         block_thread_and_exit(c);
299     }
300 
301     if (c->blocked_threads) {
302         wake_blocked_threads(c);
303     }
304 
305     if (c->tag.FIFOPtr < ITC_CELL_DEPTH) {
306         int idx = (c->fifo_out + c->tag.FIFOPtr) % ITC_CELL_DEPTH;
307         c->data[idx] = val;
308         c->tag.FIFOPtr++;
309     }
310 
311     if (c->tag.FIFOPtr == ITC_CELL_DEPTH) {
312         c->tag.F = 1;
313     }
314 }
315 
316 static void view_ef_sync_write(ITCStorageCell *c, uint64_t val)
317 {
318     view_ef_common_write(c, val, true);
319 }
320 
321 static void view_ef_try_write(ITCStorageCell *c, uint64_t val)
322 {
323     view_ef_common_write(c, val, false);
324 }
325 
326 /* ITC P/V View */
327 
328 static uint64_t view_pv_common_read(ITCStorageCell *c, bool blocking)
329 {
330     uint64_t ret = c->data[0];
331 
332     if (c->tag.FIFO) {
333         return 0;
334     }
335 
336     if (c->data[0] > 0) {
337         c->data[0]--;
338     } else if (blocking) {
339         block_thread_and_exit(c);
340     }
341 
342     return ret;
343 }
344 
345 static uint64_t view_pv_sync_read(ITCStorageCell *c)
346 {
347     return view_pv_common_read(c, true);
348 }
349 
350 static uint64_t view_pv_try_read(ITCStorageCell *c)
351 {
352     return view_pv_common_read(c, false);
353 }
354 
355 static inline void view_pv_common_write(ITCStorageCell *c)
356 {
357     if (c->tag.FIFO) {
358         return;
359     }
360 
361     if (c->data[0] < ITC_CELL_PV_MAX_VAL) {
362         c->data[0]++;
363     }
364 
365     if (c->blocked_threads) {
366         wake_blocked_threads(c);
367     }
368 }
369 
370 static void view_pv_sync_write(ITCStorageCell *c)
371 {
372     view_pv_common_write(c);
373 }
374 
375 static void view_pv_try_write(ITCStorageCell *c)
376 {
377     view_pv_common_write(c);
378 }
379 
380 static void raise_exception(int excp)
381 {
382     current_cpu->exception_index = excp;
383     cpu_loop_exit(current_cpu);
384 }
385 
386 static uint64_t itc_storage_read(void *opaque, hwaddr addr, unsigned size)
387 {
388     MIPSITUState *s = (MIPSITUState *)opaque;
389     ITCStorageCell *cell = get_cell(s, addr);
390     ITCView view = get_itc_view(addr);
391     uint64_t ret = -1;
392 
393     switch (size) {
394     case 1:
395     case 2:
396         s->icr0 |= 1 << ITC_ICR0_ERR_AXI;
397         raise_exception(EXCP_DBE);
398         return 0;
399     }
400 
401     switch (view) {
402     case ITCVIEW_BYPASS:
403         ret = view_bypass_read(cell);
404         break;
405     case ITCVIEW_CONTROL:
406         ret = view_control_read(cell);
407         break;
408     case ITCVIEW_EF_SYNC:
409         ret = view_ef_sync_read(cell);
410         break;
411     case ITCVIEW_EF_TRY:
412         ret = view_ef_try_read(cell);
413         break;
414     case ITCVIEW_PV_SYNC:
415         ret = view_pv_sync_read(cell);
416         break;
417     case ITCVIEW_PV_TRY:
418         ret = view_pv_try_read(cell);
419         break;
420     case ITCVIEW_PV_ICR0:
421         ret = s->icr0;
422         break;
423     default:
424         qemu_log_mask(LOG_GUEST_ERROR,
425                       "itc_storage_read: Bad ITC View %d\n", (int)view);
426         break;
427     }
428 
429     return ret;
430 }
431 
432 static void itc_storage_write(void *opaque, hwaddr addr, uint64_t data,
433                               unsigned size)
434 {
435     MIPSITUState *s = (MIPSITUState *)opaque;
436     ITCStorageCell *cell = get_cell(s, addr);
437     ITCView view = get_itc_view(addr);
438 
439     switch (size) {
440     case 1:
441     case 2:
442         s->icr0 |= 1 << ITC_ICR0_ERR_AXI;
443         raise_exception(EXCP_DBE);
444         return;
445     }
446 
447     switch (view) {
448     case ITCVIEW_BYPASS:
449         view_bypass_write(cell, data);
450         break;
451     case ITCVIEW_CONTROL:
452         view_control_write(cell, data);
453         break;
454     case ITCVIEW_EF_SYNC:
455         view_ef_sync_write(cell, data);
456         break;
457     case ITCVIEW_EF_TRY:
458         view_ef_try_write(cell, data);
459         break;
460     case ITCVIEW_PV_SYNC:
461         view_pv_sync_write(cell);
462         break;
463     case ITCVIEW_PV_TRY:
464         view_pv_try_write(cell);
465         break;
466     case ITCVIEW_PV_ICR0:
467         if (data & 0x7) {
468             /* clear ERROR bits */
469             s->icr0 &= ~(data & 0x7);
470         }
471         /* set BLK_GRAIN */
472         s->icr0 &= ~0x700;
473         s->icr0 |= data & 0x700;
474         break;
475     default:
476         qemu_log_mask(LOG_GUEST_ERROR,
477                       "itc_storage_write: Bad ITC View %d\n", (int)view);
478         break;
479     }
480 
481 }
482 
483 static const MemoryRegionOps itc_storage_ops = {
484     .read = itc_storage_read,
485     .write = itc_storage_write,
486     .endianness = DEVICE_NATIVE_ENDIAN,
487 };
488 
489 static void itc_reset_cells(MIPSITUState *s)
490 {
491     int i;
492 
493     memset(s->cell, 0, get_num_cells(s) * sizeof(s->cell[0]));
494 
495     for (i = 0; i < s->num_fifo; i++) {
496         s->cell[i].tag.E = 1;
497         s->cell[i].tag.FIFO = 1;
498         s->cell[i].tag.FIFODepth = ITC_CELL_DEPTH_SHIFT;
499     }
500 }
501 
502 static void mips_itu_init(Object *obj)
503 {
504     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
505     MIPSITUState *s = MIPS_ITU(obj);
506 
507     memory_region_init_io(&s->storage_io, OBJECT(s), &itc_storage_ops, s,
508                           "mips-itc-storage", ITC_STORAGE_ADDRSPACE_SZ);
509     sysbus_init_mmio(sbd, &s->storage_io);
510 
511     memory_region_init_io(&s->tag_io, OBJECT(s), &itc_tag_ops, s,
512                           "mips-itc-tag", ITC_TAG_ADDRSPACE_SZ);
513 }
514 
515 static void mips_itu_realize(DeviceState *dev, Error **errp)
516 {
517     MIPSITUState *s = MIPS_ITU(dev);
518 
519     if (s->num_fifo > ITC_FIFO_NUM_MAX) {
520         error_setg(errp, "Exceed maximum number of FIFO cells: %d",
521                    s->num_fifo);
522         return;
523     }
524     if (s->num_semaphores > ITC_SEMAPH_NUM_MAX) {
525         error_setg(errp, "Exceed maximum number of Semaphore cells: %d",
526                    s->num_semaphores);
527         return;
528     }
529 
530     s->cell = g_new(ITCStorageCell, get_num_cells(s));
531 }
532 
533 static void mips_itu_reset(DeviceState *dev)
534 {
535     MIPSITUState *s = MIPS_ITU(dev);
536 
537     if (s->saar_present) {
538         *(uint64_t *) s->saar = 0x11 << 1;
539         s->icr0 = get_num_cells(s) << ITC_ICR0_CELL_NUM;
540     } else {
541         s->ITCAddressMap[0] = 0;
542         s->ITCAddressMap[1] =
543             ((ITC_STORAGE_ADDRSPACE_SZ - 1) & ITC_AM1_ADDR_MASK_MASK) |
544             (get_num_cells(s) << ITC_AM1_NUMENTRIES_OFS);
545     }
546     itc_reconfigure(s);
547 
548     itc_reset_cells(s);
549 }
550 
551 static Property mips_itu_properties[] = {
552     DEFINE_PROP_INT32("num-fifo", MIPSITUState, num_fifo,
553                       ITC_FIFO_NUM_MAX),
554     DEFINE_PROP_INT32("num-semaphores", MIPSITUState, num_semaphores,
555                       ITC_SEMAPH_NUM_MAX),
556     DEFINE_PROP_BOOL("saar-present", MIPSITUState, saar_present, false),
557     DEFINE_PROP_END_OF_LIST(),
558 };
559 
560 static void mips_itu_class_init(ObjectClass *klass, void *data)
561 {
562     DeviceClass *dc = DEVICE_CLASS(klass);
563 
564     device_class_set_props(dc, mips_itu_properties);
565     dc->realize = mips_itu_realize;
566     dc->reset = mips_itu_reset;
567 }
568 
569 static const TypeInfo mips_itu_info = {
570     .name          = TYPE_MIPS_ITU,
571     .parent        = TYPE_SYS_BUS_DEVICE,
572     .instance_size = sizeof(MIPSITUState),
573     .instance_init = mips_itu_init,
574     .class_init    = mips_itu_class_init,
575 };
576 
577 static void mips_itu_register_types(void)
578 {
579     type_register_static(&mips_itu_info);
580 }
581 
582 type_init(mips_itu_register_types)
583