xref: /openbmc/qemu/hw/gpio/npcm7xx_gpio.c (revision 284d697c)
1 /*
2  * Nuvoton NPCM7xx General Purpose Input / Output (GPIO)
3  *
4  * Copyright 2020 Google LLC
5  *
6  * This program is free software; you can redistribute it and/or
7  * modify it under the terms of the GNU General Public License
8  * version 2 as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13  * GNU General Public License for more details.
14  */
15 
16 #include "qemu/osdep.h"
17 
18 #include "hw/gpio/npcm7xx_gpio.h"
19 #include "hw/irq.h"
20 #include "hw/qdev-properties.h"
21 #include "migration/vmstate.h"
22 #include "qapi/error.h"
23 #include "qemu/log.h"
24 #include "qemu/module.h"
25 #include "qemu/units.h"
26 #include "trace.h"
27 
28 /* 32-bit register indices. */
29 enum NPCM7xxGPIORegister {
30     NPCM7XX_GPIO_TLOCK1,
31     NPCM7XX_GPIO_DIN,
32     NPCM7XX_GPIO_POL,
33     NPCM7XX_GPIO_DOUT,
34     NPCM7XX_GPIO_OE,
35     NPCM7XX_GPIO_OTYP,
36     NPCM7XX_GPIO_MP,
37     NPCM7XX_GPIO_PU,
38     NPCM7XX_GPIO_PD,
39     NPCM7XX_GPIO_DBNC,
40     NPCM7XX_GPIO_EVTYP,
41     NPCM7XX_GPIO_EVBE,
42     NPCM7XX_GPIO_OBL0,
43     NPCM7XX_GPIO_OBL1,
44     NPCM7XX_GPIO_OBL2,
45     NPCM7XX_GPIO_OBL3,
46     NPCM7XX_GPIO_EVEN,
47     NPCM7XX_GPIO_EVENS,
48     NPCM7XX_GPIO_EVENC,
49     NPCM7XX_GPIO_EVST,
50     NPCM7XX_GPIO_SPLCK,
51     NPCM7XX_GPIO_MPLCK,
52     NPCM7XX_GPIO_IEM,
53     NPCM7XX_GPIO_OSRC,
54     NPCM7XX_GPIO_ODSC,
55     NPCM7XX_GPIO_DOS = 0x68 / sizeof(uint32_t),
56     NPCM7XX_GPIO_DOC,
57     NPCM7XX_GPIO_OES,
58     NPCM7XX_GPIO_OEC,
59     NPCM7XX_GPIO_TLOCK2 = 0x7c / sizeof(uint32_t),
60     NPCM7XX_GPIO_REGS_END,
61 };
62 
63 #define NPCM7XX_GPIO_REGS_SIZE (4 * KiB)
64 
65 #define NPCM7XX_GPIO_LOCK_MAGIC1 (0xc0defa73)
66 #define NPCM7XX_GPIO_LOCK_MAGIC2 (0xc0de1248)
67 
68 static void npcm7xx_gpio_update_events(NPCM7xxGPIOState *s, uint32_t din_diff)
69 {
70     uint32_t din_new = s->regs[NPCM7XX_GPIO_DIN];
71 
72     /* Trigger on high level */
73     s->regs[NPCM7XX_GPIO_EVST] |= din_new & ~s->regs[NPCM7XX_GPIO_EVTYP];
74     /* Trigger on both edges */
75     s->regs[NPCM7XX_GPIO_EVST] |= (din_diff & s->regs[NPCM7XX_GPIO_EVTYP]
76                                    & s->regs[NPCM7XX_GPIO_EVBE]);
77     /* Trigger on rising edge */
78     s->regs[NPCM7XX_GPIO_EVST] |= (din_diff & din_new
79                                    & s->regs[NPCM7XX_GPIO_EVTYP]);
80 
81     trace_npcm7xx_gpio_update_events(DEVICE(s)->canonical_path,
82                                      s->regs[NPCM7XX_GPIO_EVST],
83                                      s->regs[NPCM7XX_GPIO_EVEN]);
84     qemu_set_irq(s->irq, !!(s->regs[NPCM7XX_GPIO_EVST]
85                             & s->regs[NPCM7XX_GPIO_EVEN]));
86 }
87 
88 static void npcm7xx_gpio_update_pins(NPCM7xxGPIOState *s, uint32_t diff)
89 {
90     uint32_t drive_en;
91     uint32_t drive_lvl;
92     uint32_t not_driven;
93     uint32_t undefined;
94     uint32_t pin_diff;
95     uint32_t din_old;
96 
97     /* Calculate level of each pin driven by GPIO controller. */
98     drive_lvl = s->regs[NPCM7XX_GPIO_DOUT] ^ s->regs[NPCM7XX_GPIO_POL];
99     /* If OTYP=1, only drive low (open drain) */
100     drive_en = s->regs[NPCM7XX_GPIO_OE] & ~(s->regs[NPCM7XX_GPIO_OTYP]
101                                             & drive_lvl);
102     /*
103      * If a pin is driven to opposite levels by the GPIO controller and the
104      * external driver, the result is undefined.
105      */
106     undefined = drive_en & s->ext_driven & (drive_lvl ^ s->ext_level);
107     if (undefined) {
108         qemu_log_mask(LOG_GUEST_ERROR,
109                       "%s: pins have multiple drivers: 0x%" PRIx32 "\n",
110                       DEVICE(s)->canonical_path, undefined);
111     }
112 
113     not_driven = ~(drive_en | s->ext_driven);
114     pin_diff = s->pin_level;
115 
116     /* Set pins to externally driven level. */
117     s->pin_level = s->ext_level & s->ext_driven;
118     /* Set internally driven pins, ignoring any conflicts. */
119     s->pin_level |= drive_lvl & drive_en;
120     /* Pull up undriven pins with internal pull-up enabled. */
121     s->pin_level |= not_driven & s->regs[NPCM7XX_GPIO_PU];
122     /* Pins not driven, pulled up or pulled down are undefined */
123     undefined |= not_driven & ~(s->regs[NPCM7XX_GPIO_PU]
124                                 | s->regs[NPCM7XX_GPIO_PD]);
125 
126     /* If any pins changed state, update the outgoing GPIOs. */
127     pin_diff ^= s->pin_level;
128     pin_diff |= undefined & diff;
129     if (pin_diff) {
130         int i;
131 
132         for (i = 0; i < NPCM7XX_GPIO_NR_PINS; i++) {
133             uint32_t mask = BIT(i);
134             if (pin_diff & mask) {
135                 int level = (undefined & mask) ? -1 : !!(s->pin_level & mask);
136                 trace_npcm7xx_gpio_set_output(DEVICE(s)->canonical_path,
137                                               i, level);
138                 qemu_set_irq(s->output[i], level);
139             }
140         }
141     }
142 
143     /* Calculate new value of DIN after masking and polarity setting. */
144     din_old = s->regs[NPCM7XX_GPIO_DIN];
145     s->regs[NPCM7XX_GPIO_DIN] = ((s->pin_level & s->regs[NPCM7XX_GPIO_IEM])
146                                  ^ s->regs[NPCM7XX_GPIO_POL]);
147 
148     /* See if any new events triggered because of all this. */
149     npcm7xx_gpio_update_events(s, din_old ^ s->regs[NPCM7XX_GPIO_DIN]);
150 }
151 
152 static bool npcm7xx_gpio_is_locked(NPCM7xxGPIOState *s)
153 {
154     return s->regs[NPCM7XX_GPIO_TLOCK1] == 1;
155 }
156 
157 static uint64_t npcm7xx_gpio_regs_read(void *opaque, hwaddr addr,
158                                        unsigned int size)
159 {
160     hwaddr reg = addr / sizeof(uint32_t);
161     NPCM7xxGPIOState *s = opaque;
162     uint64_t value = 0;
163 
164     switch (reg) {
165     case NPCM7XX_GPIO_TLOCK1 ... NPCM7XX_GPIO_EVEN:
166     case NPCM7XX_GPIO_EVST ... NPCM7XX_GPIO_ODSC:
167         value = s->regs[reg];
168         break;
169 
170     case NPCM7XX_GPIO_EVENS ... NPCM7XX_GPIO_EVENC:
171     case NPCM7XX_GPIO_DOS ... NPCM7XX_GPIO_TLOCK2:
172         qemu_log_mask(LOG_GUEST_ERROR,
173                       "%s: read from write-only register 0x%" HWADDR_PRIx "\n",
174                       DEVICE(s)->canonical_path, addr);
175         break;
176 
177     default:
178         qemu_log_mask(LOG_GUEST_ERROR,
179                       "%s: read from invalid offset 0x%" HWADDR_PRIx "\n",
180                       DEVICE(s)->canonical_path, addr);
181         break;
182     }
183 
184     trace_npcm7xx_gpio_read(DEVICE(s)->canonical_path, addr, value);
185 
186     return value;
187 }
188 
189 static void npcm7xx_gpio_regs_write(void *opaque, hwaddr addr, uint64_t v,
190                                     unsigned int size)
191 {
192     hwaddr reg = addr / sizeof(uint32_t);
193     NPCM7xxGPIOState *s = opaque;
194     uint32_t value = v;
195     uint32_t diff;
196 
197     trace_npcm7xx_gpio_write(DEVICE(s)->canonical_path, addr, v);
198 
199     if (npcm7xx_gpio_is_locked(s)) {
200         switch (reg) {
201         case NPCM7XX_GPIO_TLOCK1:
202             if (s->regs[NPCM7XX_GPIO_TLOCK2] == NPCM7XX_GPIO_LOCK_MAGIC2 &&
203                 value == NPCM7XX_GPIO_LOCK_MAGIC1) {
204                 s->regs[NPCM7XX_GPIO_TLOCK1] = 0;
205                 s->regs[NPCM7XX_GPIO_TLOCK2] = 0;
206             }
207             break;
208 
209         case NPCM7XX_GPIO_TLOCK2:
210             s->regs[reg] = value;
211             break;
212 
213         default:
214             qemu_log_mask(LOG_GUEST_ERROR,
215                           "%s: write to locked register @ 0x%" HWADDR_PRIx "\n",
216                           DEVICE(s)->canonical_path, addr);
217             break;
218         }
219 
220         return;
221     }
222 
223     diff = s->regs[reg] ^ value;
224 
225     switch (reg) {
226     case NPCM7XX_GPIO_TLOCK1:
227     case NPCM7XX_GPIO_TLOCK2:
228         s->regs[NPCM7XX_GPIO_TLOCK1] = 1;
229         s->regs[NPCM7XX_GPIO_TLOCK2] = 0;
230         break;
231 
232     case NPCM7XX_GPIO_DIN:
233         qemu_log_mask(LOG_GUEST_ERROR,
234                       "%s: write to read-only register @ 0x%" HWADDR_PRIx "\n",
235                       DEVICE(s)->canonical_path, addr);
236         break;
237 
238     case NPCM7XX_GPIO_POL:
239     case NPCM7XX_GPIO_DOUT:
240     case NPCM7XX_GPIO_OE:
241     case NPCM7XX_GPIO_OTYP:
242     case NPCM7XX_GPIO_PU:
243     case NPCM7XX_GPIO_PD:
244     case NPCM7XX_GPIO_IEM:
245         s->regs[reg] = value;
246         npcm7xx_gpio_update_pins(s, diff);
247         break;
248 
249     case NPCM7XX_GPIO_DOS:
250         s->regs[NPCM7XX_GPIO_DOUT] |= value;
251         npcm7xx_gpio_update_pins(s, value);
252         break;
253     case NPCM7XX_GPIO_DOC:
254         s->regs[NPCM7XX_GPIO_DOUT] &= ~value;
255         npcm7xx_gpio_update_pins(s, value);
256         break;
257     case NPCM7XX_GPIO_OES:
258         s->regs[NPCM7XX_GPIO_OE] |= value;
259         npcm7xx_gpio_update_pins(s, value);
260         break;
261     case NPCM7XX_GPIO_OEC:
262         s->regs[NPCM7XX_GPIO_OE] &= ~value;
263         npcm7xx_gpio_update_pins(s, value);
264         break;
265 
266     case NPCM7XX_GPIO_EVTYP:
267     case NPCM7XX_GPIO_EVBE:
268     case NPCM7XX_GPIO_EVEN:
269         s->regs[reg] = value;
270         npcm7xx_gpio_update_events(s, 0);
271         break;
272 
273     case NPCM7XX_GPIO_EVENS:
274         s->regs[NPCM7XX_GPIO_EVEN] |= value;
275         npcm7xx_gpio_update_events(s, 0);
276         break;
277     case NPCM7XX_GPIO_EVENC:
278         s->regs[NPCM7XX_GPIO_EVEN] &= ~value;
279         npcm7xx_gpio_update_events(s, 0);
280         break;
281 
282     case NPCM7XX_GPIO_EVST:
283         s->regs[reg] &= ~value;
284         npcm7xx_gpio_update_events(s, 0);
285         break;
286 
287     case NPCM7XX_GPIO_MP:
288     case NPCM7XX_GPIO_DBNC:
289     case NPCM7XX_GPIO_OSRC:
290     case NPCM7XX_GPIO_ODSC:
291         /* Nothing to do; just store the value. */
292         s->regs[reg] = value;
293         break;
294 
295     case NPCM7XX_GPIO_OBL0:
296     case NPCM7XX_GPIO_OBL1:
297     case NPCM7XX_GPIO_OBL2:
298     case NPCM7XX_GPIO_OBL3:
299         s->regs[reg] = value;
300         qemu_log_mask(LOG_UNIMP, "%s: Blinking is not implemented\n",
301                       __func__);
302         break;
303 
304     case NPCM7XX_GPIO_SPLCK:
305     case NPCM7XX_GPIO_MPLCK:
306         qemu_log_mask(LOG_UNIMP, "%s: Per-pin lock is not implemented\n",
307                       __func__);
308         break;
309 
310     default:
311         qemu_log_mask(LOG_GUEST_ERROR,
312                       "%s: write to invalid offset 0x%" HWADDR_PRIx "\n",
313                       DEVICE(s)->canonical_path, addr);
314         break;
315     }
316 }
317 
318 static const MemoryRegionOps npcm7xx_gpio_regs_ops = {
319     .read = npcm7xx_gpio_regs_read,
320     .write = npcm7xx_gpio_regs_write,
321     .endianness = DEVICE_NATIVE_ENDIAN,
322     .valid = {
323         .min_access_size = 4,
324         .max_access_size = 4,
325         .unaligned = false,
326     },
327 };
328 
329 static void npcm7xx_gpio_set_input(void *opaque, int line, int level)
330 {
331     NPCM7xxGPIOState *s = opaque;
332 
333     trace_npcm7xx_gpio_set_input(DEVICE(s)->canonical_path, line, level);
334 
335     g_assert(line >= 0 && line < NPCM7XX_GPIO_NR_PINS);
336 
337     s->ext_driven = deposit32(s->ext_driven, line, 1, level >= 0);
338     s->ext_level = deposit32(s->ext_level, line, 1, level > 0);
339 
340     npcm7xx_gpio_update_pins(s, BIT(line));
341 }
342 
343 static void npcm7xx_gpio_enter_reset(Object *obj, ResetType type)
344 {
345     NPCM7xxGPIOState *s = NPCM7XX_GPIO(obj);
346 
347     memset(s->regs, 0, sizeof(s->regs));
348 
349     s->regs[NPCM7XX_GPIO_PU] = s->reset_pu;
350     s->regs[NPCM7XX_GPIO_PD] = s->reset_pd;
351     s->regs[NPCM7XX_GPIO_OSRC] = s->reset_osrc;
352     s->regs[NPCM7XX_GPIO_ODSC] = s->reset_odsc;
353 }
354 
355 static void npcm7xx_gpio_hold_reset(Object *obj)
356 {
357     NPCM7xxGPIOState *s = NPCM7XX_GPIO(obj);
358 
359     npcm7xx_gpio_update_pins(s, -1);
360 }
361 
362 static void npcm7xx_gpio_init(Object *obj)
363 {
364     NPCM7xxGPIOState *s = NPCM7XX_GPIO(obj);
365     DeviceState *dev = DEVICE(obj);
366 
367     memory_region_init_io(&s->mmio, obj, &npcm7xx_gpio_regs_ops, s,
368                           "regs", NPCM7XX_GPIO_REGS_SIZE);
369     sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
370     sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irq);
371 
372     qdev_init_gpio_in(dev, npcm7xx_gpio_set_input, NPCM7XX_GPIO_NR_PINS);
373     qdev_init_gpio_out(dev, s->output, NPCM7XX_GPIO_NR_PINS);
374 }
375 
376 static const VMStateDescription vmstate_npcm7xx_gpio = {
377     .name = "npcm7xx-gpio",
378     .version_id = 0,
379     .minimum_version_id = 0,
380     .fields = (VMStateField[]) {
381         VMSTATE_UINT32(pin_level, NPCM7xxGPIOState),
382         VMSTATE_UINT32(ext_level, NPCM7xxGPIOState),
383         VMSTATE_UINT32(ext_driven, NPCM7xxGPIOState),
384         VMSTATE_UINT32_ARRAY(regs, NPCM7xxGPIOState, NPCM7XX_GPIO_NR_REGS),
385         VMSTATE_END_OF_LIST(),
386     },
387 };
388 
389 static Property npcm7xx_gpio_properties[] = {
390     /* Bit n set => pin n has pullup enabled by default. */
391     DEFINE_PROP_UINT32("reset-pullup", NPCM7xxGPIOState, reset_pu, 0),
392     /* Bit n set => pin n has pulldown enabled by default. */
393     DEFINE_PROP_UINT32("reset-pulldown", NPCM7xxGPIOState, reset_pd, 0),
394     /* Bit n set => pin n has high slew rate by default. */
395     DEFINE_PROP_UINT32("reset-osrc", NPCM7xxGPIOState, reset_osrc, 0),
396     /* Bit n set => pin n has high drive strength by default. */
397     DEFINE_PROP_UINT32("reset-odsc", NPCM7xxGPIOState, reset_odsc, 0),
398     DEFINE_PROP_END_OF_LIST(),
399 };
400 
401 static void npcm7xx_gpio_class_init(ObjectClass *klass, void *data)
402 {
403     ResettableClass *reset = RESETTABLE_CLASS(klass);
404     DeviceClass *dc = DEVICE_CLASS(klass);
405 
406     QEMU_BUILD_BUG_ON(NPCM7XX_GPIO_REGS_END > NPCM7XX_GPIO_NR_REGS);
407 
408     dc->desc = "NPCM7xx GPIO Controller";
409     dc->vmsd = &vmstate_npcm7xx_gpio;
410     reset->phases.enter = npcm7xx_gpio_enter_reset;
411     reset->phases.hold = npcm7xx_gpio_hold_reset;
412     device_class_set_props(dc, npcm7xx_gpio_properties);
413 }
414 
415 static const TypeInfo npcm7xx_gpio_types[] = {
416     {
417         .name = TYPE_NPCM7XX_GPIO,
418         .parent = TYPE_SYS_BUS_DEVICE,
419         .instance_size = sizeof(NPCM7xxGPIOState),
420         .class_init = npcm7xx_gpio_class_init,
421         .instance_init = npcm7xx_gpio_init,
422     },
423 };
424 DEFINE_TYPES(npcm7xx_gpio_types);
425