xref: /openbmc/qemu/hw/misc/sifive_e_aon.c (revision 2f95279a)
1 /*
2  * SiFive HiFive1 AON (Always On Domain) for QEMU.
3  *
4  * Copyright (c) 2022 SiFive, Inc. All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms and conditions of the GNU General Public License,
8  * version 2 or later, as published by the Free Software Foundation.
9  *
10  * This program is distributed in the hope it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
13  * more details.
14  *
15  * You should have received a copy of the GNU General Public License along with
16  * this program.  If not, see <http://www.gnu.org/licenses/>.
17  */
18 
19 #include "qemu/osdep.h"
20 #include "qemu/timer.h"
21 #include "qemu/log.h"
22 #include "hw/irq.h"
23 #include "hw/registerfields.h"
24 #include "hw/misc/sifive_e_aon.h"
25 #include "qapi/visitor.h"
26 #include "qapi/error.h"
27 #include "sysemu/watchdog.h"
28 #include "hw/qdev-properties.h"
29 
30 REG32(AON_WDT_WDOGCFG, 0x0)
31     FIELD(AON_WDT_WDOGCFG, SCALE, 0, 4)
32     FIELD(AON_WDT_WDOGCFG, RSVD0, 4, 4)
33     FIELD(AON_WDT_WDOGCFG, RSTEN, 8, 1)
34     FIELD(AON_WDT_WDOGCFG, ZEROCMP, 9, 1)
35     FIELD(AON_WDT_WDOGCFG, RSVD1, 10, 2)
36     FIELD(AON_WDT_WDOGCFG, EN_ALWAYS, 12, 1)
37     FIELD(AON_WDT_WDOGCFG, EN_CORE_AWAKE, 13, 1)
38     FIELD(AON_WDT_WDOGCFG, RSVD2, 14, 14)
39     FIELD(AON_WDT_WDOGCFG, IP0, 28, 1)
40     FIELD(AON_WDT_WDOGCFG, RSVD3, 29, 3)
41 REG32(AON_WDT_WDOGCOUNT, 0x8)
42     FIELD(AON_WDT_WDOGCOUNT, VALUE, 0, 31)
43 REG32(AON_WDT_WDOGS, 0x10)
44 REG32(AON_WDT_WDOGFEED, 0x18)
45 REG32(AON_WDT_WDOGKEY, 0x1c)
46 REG32(AON_WDT_WDOGCMP0, 0x20)
47 
48 static void sifive_e_aon_wdt_update_wdogcount(SiFiveEAONState *r)
49 {
50     int64_t now;
51     if (FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, EN_ALWAYS) == 0 &&
52         FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, EN_CORE_AWAKE) == 0) {
53         return;
54     }
55 
56     now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
57     r->wdogcount += muldiv64(now - r->wdog_restart_time,
58                              r->wdogclk_freq, NANOSECONDS_PER_SECOND);
59 
60     /* Clean the most significant bit. */
61     r->wdogcount &= R_AON_WDT_WDOGCOUNT_VALUE_MASK;
62     r->wdog_restart_time = now;
63 }
64 
65 static void sifive_e_aon_wdt_update_state(SiFiveEAONState *r)
66 {
67     uint16_t wdogs;
68     bool cmp_signal = false;
69     sifive_e_aon_wdt_update_wdogcount(r);
70     wdogs = (uint16_t)(r->wdogcount >>
71                            FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, SCALE));
72 
73     if (wdogs >= r->wdogcmp0) {
74         cmp_signal = true;
75         if (FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, ZEROCMP) == 1) {
76             r->wdogcount = 0;
77             wdogs = 0;
78         }
79     }
80 
81     if (cmp_signal) {
82         if (FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, RSTEN) == 1) {
83             watchdog_perform_action();
84         }
85         r->wdogcfg = FIELD_DP32(r->wdogcfg, AON_WDT_WDOGCFG, IP0, 1);
86     }
87 
88     qemu_set_irq(r->wdog_irq, FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, IP0));
89 
90     if (wdogs < r->wdogcmp0 &&
91         (FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, EN_ALWAYS) == 1 ||
92          FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, EN_CORE_AWAKE) == 1)) {
93         int64_t next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
94         next += muldiv64((r->wdogcmp0 - wdogs) <<
95                          FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, SCALE),
96                          NANOSECONDS_PER_SECOND, r->wdogclk_freq);
97         timer_mod(r->wdog_timer, next);
98     } else {
99         timer_mod(r->wdog_timer, INT64_MAX);
100     }
101 }
102 
103 /*
104  * Callback used when the timer set using timer_mod expires.
105  */
106 static void sifive_e_aon_wdt_expired_cb(void *opaque)
107 {
108     SiFiveEAONState *r = SIFIVE_E_AON(opaque);
109     sifive_e_aon_wdt_update_state(r);
110 }
111 
112 static uint64_t
113 sifive_e_aon_wdt_read(void *opaque, hwaddr addr, unsigned int size)
114 {
115     SiFiveEAONState *r = SIFIVE_E_AON(opaque);
116 
117     switch (addr) {
118     case A_AON_WDT_WDOGCFG:
119         return r->wdogcfg;
120     case A_AON_WDT_WDOGCOUNT:
121         sifive_e_aon_wdt_update_wdogcount(r);
122         return r->wdogcount;
123     case A_AON_WDT_WDOGS:
124         sifive_e_aon_wdt_update_wdogcount(r);
125         return r->wdogcount >>
126                FIELD_EX32(r->wdogcfg,
127                           AON_WDT_WDOGCFG,
128                           SCALE);
129     case A_AON_WDT_WDOGFEED:
130         return 0;
131     case A_AON_WDT_WDOGKEY:
132         return r->wdogunlock;
133     case A_AON_WDT_WDOGCMP0:
134         return r->wdogcmp0;
135     default:
136         qemu_log_mask(LOG_GUEST_ERROR, "%s: bad read: addr=0x%x\n",
137                       __func__, (int)addr);
138     }
139 
140     return 0;
141 }
142 
143 static void
144 sifive_e_aon_wdt_write(void *opaque, hwaddr addr,
145                        uint64_t val64, unsigned int size)
146 {
147     SiFiveEAONState *r = SIFIVE_E_AON(opaque);
148     uint32_t value = val64;
149 
150     switch (addr) {
151     case A_AON_WDT_WDOGCFG: {
152         uint8_t new_en_always;
153         uint8_t new_en_core_awake;
154         uint8_t old_en_always;
155         uint8_t old_en_core_awake;
156         if (r->wdogunlock == 0) {
157             return;
158         }
159 
160         new_en_always = FIELD_EX32(value, AON_WDT_WDOGCFG, EN_ALWAYS);
161         new_en_core_awake = FIELD_EX32(value, AON_WDT_WDOGCFG, EN_CORE_AWAKE);
162         old_en_always = FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG, EN_ALWAYS);
163         old_en_core_awake = FIELD_EX32(r->wdogcfg, AON_WDT_WDOGCFG,
164                                        EN_CORE_AWAKE);
165 
166         if ((old_en_always ||
167              old_en_core_awake) == 1 &&
168             (new_en_always ||
169              new_en_core_awake) == 0) {
170             sifive_e_aon_wdt_update_wdogcount(r);
171         } else if ((old_en_always ||
172                     old_en_core_awake) == 0 &&
173                    (new_en_always ||
174                     new_en_core_awake) == 1) {
175             r->wdog_restart_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
176         }
177         r->wdogcfg = value;
178         r->wdogunlock = 0;
179         break;
180     }
181     case A_AON_WDT_WDOGCOUNT:
182         if (r->wdogunlock == 0) {
183             return;
184         }
185         r->wdogcount = value & R_AON_WDT_WDOGCOUNT_VALUE_MASK;
186         r->wdog_restart_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
187         r->wdogunlock = 0;
188         break;
189     case A_AON_WDT_WDOGS:
190         return;
191     case A_AON_WDT_WDOGFEED:
192         if (r->wdogunlock == 0) {
193             return;
194         }
195         if (value == SIFIVE_E_AON_WDOGFEED) {
196             r->wdogcount = 0;
197             r->wdog_restart_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
198         }
199         r->wdogunlock = 0;
200         break;
201     case A_AON_WDT_WDOGKEY:
202         if (value == SIFIVE_E_AON_WDOGKEY) {
203             r->wdogunlock = 1;
204         }
205         break;
206     case A_AON_WDT_WDOGCMP0:
207         if (r->wdogunlock == 0) {
208             return;
209         }
210         r->wdogcmp0 = (uint16_t) value;
211         r->wdogunlock = 0;
212         break;
213     default:
214         qemu_log_mask(LOG_GUEST_ERROR, "%s: bad write: addr=0x%x v=0x%x\n",
215                       __func__, (int)addr, (int)value);
216     }
217     sifive_e_aon_wdt_update_state(r);
218 }
219 
220 static uint64_t
221 sifive_e_aon_read(void *opaque, hwaddr addr, unsigned int size)
222 {
223     if (addr < SIFIVE_E_AON_RTC) {
224         return sifive_e_aon_wdt_read(opaque, addr, size);
225     } else if (addr < SIFIVE_E_AON_MAX) {
226         qemu_log_mask(LOG_UNIMP, "%s: Unimplemented read: addr=0x%x\n",
227                       __func__, (int)addr);
228     } else {
229         qemu_log_mask(LOG_GUEST_ERROR, "%s: bad read: addr=0x%x\n",
230                       __func__, (int)addr);
231     }
232     return 0;
233 }
234 
235 static void
236 sifive_e_aon_write(void *opaque, hwaddr addr,
237                    uint64_t val64, unsigned int size)
238 {
239     if (addr < SIFIVE_E_AON_RTC) {
240         sifive_e_aon_wdt_write(opaque, addr, val64, size);
241     } else if (addr < SIFIVE_E_AON_MAX) {
242         qemu_log_mask(LOG_UNIMP, "%s: Unimplemented write: addr=0x%x\n",
243                       __func__, (int)addr);
244     } else {
245         qemu_log_mask(LOG_GUEST_ERROR, "%s: bad write: addr=0x%x\n",
246                       __func__, (int)addr);
247     }
248 }
249 
250 static const MemoryRegionOps sifive_e_aon_ops = {
251     .read = sifive_e_aon_read,
252     .write = sifive_e_aon_write,
253     .endianness = DEVICE_NATIVE_ENDIAN,
254     .impl = {
255         .min_access_size = 4,
256         .max_access_size = 4
257     },
258     .valid = {
259         .min_access_size = 4,
260         .max_access_size = 4
261     }
262 };
263 
264 static void sifive_e_aon_reset(DeviceState *dev)
265 {
266     SiFiveEAONState *r = SIFIVE_E_AON(dev);
267 
268     r->wdogcfg = FIELD_DP32(r->wdogcfg, AON_WDT_WDOGCFG, RSTEN, 0);
269     r->wdogcfg = FIELD_DP32(r->wdogcfg, AON_WDT_WDOGCFG, EN_ALWAYS, 0);
270     r->wdogcfg = FIELD_DP32(r->wdogcfg, AON_WDT_WDOGCFG, EN_CORE_AWAKE, 0);
271     r->wdogcmp0 = 0xbeef;
272 
273     sifive_e_aon_wdt_update_state(r);
274 }
275 
276 static void sifive_e_aon_init(Object *obj)
277 {
278     SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
279     SiFiveEAONState *r = SIFIVE_E_AON(obj);
280 
281     memory_region_init_io(&r->mmio, OBJECT(r), &sifive_e_aon_ops, r,
282                           TYPE_SIFIVE_E_AON, SIFIVE_E_AON_MAX);
283     sysbus_init_mmio(sbd, &r->mmio);
284 
285     /* watchdog timer */
286     r->wdog_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
287                                  sifive_e_aon_wdt_expired_cb, r);
288     r->wdogclk_freq = SIFIVE_E_LFCLK_DEFAULT_FREQ;
289     sysbus_init_irq(sbd, &r->wdog_irq);
290 }
291 
292 static Property sifive_e_aon_properties[] = {
293     DEFINE_PROP_UINT64("wdogclk-frequency", SiFiveEAONState, wdogclk_freq,
294                        SIFIVE_E_LFCLK_DEFAULT_FREQ),
295     DEFINE_PROP_END_OF_LIST(),
296 };
297 
298 static void sifive_e_aon_class_init(ObjectClass *oc, void *data)
299 {
300     DeviceClass *dc = DEVICE_CLASS(oc);
301 
302     dc->reset = sifive_e_aon_reset;
303     device_class_set_props(dc, sifive_e_aon_properties);
304 }
305 
306 static const TypeInfo sifive_e_aon_info = {
307     .name          = TYPE_SIFIVE_E_AON,
308     .parent        = TYPE_SYS_BUS_DEVICE,
309     .instance_size = sizeof(SiFiveEAONState),
310     .instance_init = sifive_e_aon_init,
311     .class_init    = sifive_e_aon_class_init,
312 };
313 
314 static void sifive_e_aon_register_types(void)
315 {
316     type_register_static(&sifive_e_aon_info);
317 }
318 
319 type_init(sifive_e_aon_register_types)
320