hw/timer/i8254_common.c

   1 /*
   2  * QEMU 8253/8254 - common bits of emulated and KVM kernel model
   3  *
   4  * Copyright (c) 2003-2004 Fabrice Bellard
   5  * Copyright (c) 2012      Jan Kiszka, Siemens AG
   6  *
   7  * Permission is hereby granted, free of charge, to any person obtaining a copy
   8  * of this software and associated documentation files (the "Software"), to deal
   9  * in the Software without restriction, including without limitation the rights
  10  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11  * copies of the Software, and to permit persons to whom the Software is
  12  * furnished to do so, subject to the following conditions:
  13  *
  14  * The above copyright notice and this permission notice shall be included in
  15  * all copies or substantial portions of the Software.
  16  *
  17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23  * THE SOFTWARE.
  24  */
  25
  26 #include "qemu/osdep.h"
  27 #include "hw/isa/isa.h"
  28 #include "qemu/module.h"
  29 #include "qemu/timer.h"
  30 #include "hw/timer/i8254.h"
  31 #include "hw/timer/i8254_internal.h"
  32 #include "migration/vmstate.h"
  33
  34 /* val must be 0 or 1 */
  35 void pit_set_gate(ISADevice *dev, int channel, int val)
  36 {
  37     PITCommonState *pit = PIT_COMMON(dev);
  38     PITChannelState *s = &pit->channels[channel];
  39     PITCommonClass *c = PIT_COMMON_GET_CLASS(pit);
  40
  41     c->set_channel_gate(pit, s, val);
  42 }
  43
  44 /* get pit output bit */
  45 int pit_get_out(PITChannelState *s, int64_t current_time)
  46 {
  47     uint64_t d;
  48     int out;
  49
  50     d = muldiv64(current_time - s->count_load_time, PIT_FREQ,
  51                  NANOSECONDS_PER_SECOND);
  52     switch (s->mode) {
  53     default:
  54     case 0:
  55         out = (d >= s->count);
  56         break;
  57     case 1:
  58         out = (d < s->count);
  59         break;
  60     case 2:
  61         if ((d % s->count) == 0 && d != 0) {
  62             out = 1;
  63         } else {
  64             out = 0;
  65         }
  66         break;
  67     case 3:
  68         out = (d % s->count) < ((s->count + 1) >> 1);
  69         break;
  70     case 4:
  71     case 5:
  72         out = (d == s->count);
  73         break;
  74     }
  75     return out;
  76 }
  77
  78 /* return -1 if no transition will occur.  */
  79 int64_t pit_get_next_transition_time(PITChannelState *s, int64_t current_time)
  80 {
  81     uint64_t d, next_time, base;
  82     int period2;
  83
  84     d = muldiv64(current_time - s->count_load_time, PIT_FREQ,
  85                  NANOSECONDS_PER_SECOND);
  86     switch (s->mode) {
  87     default:
  88     case 0:
  89     case 1:
  90         if (d < s->count) {
  91             next_time = s->count;
  92         } else {
  93             return -1;
  94         }
  95         break;
  96     case 2:
  97         base = QEMU_ALIGN_DOWN(d, s->count);
  98         if ((d - base) == 0 && d != 0) {
  99             next_time = base + s->count;
 100         } else {
 101             next_time = base + s->count + 1;
 102         }
 103         break;
 104     case 3:
 105         base = QEMU_ALIGN_DOWN(d, s->count);
 106         period2 = ((s->count + 1) >> 1);
 107         if ((d - base) < period2) {
 108             next_time = base + period2;
 109         } else {
 110             next_time = base + s->count;
 111         }
 112         break;
 113     case 4:
 114     case 5:
 115         if (d < s->count) {
 116             next_time = s->count;
 117         } else if (d == s->count) {
 118             next_time = s->count + 1;
 119         } else {
 120             return -1;
 121         }
 122         break;
 123     }
 124     /* convert to timer units */
 125     next_time = s->count_load_time + muldiv64(next_time, NANOSECONDS_PER_SECOND,
 126                                               PIT_FREQ);
 127     /* fix potential rounding problems */
 128     /* XXX: better solution: use a clock at PIT_FREQ Hz */
 129     if (next_time <= current_time) {
 130         next_time = current_time + 1;
 131     }
 132     return next_time;
 133 }
 134
 135 void pit_get_channel_info_common(PITCommonState *s, PITChannelState *sc,
 136                                  PITChannelInfo *info)
 137 {
 138     info->gate = sc->gate;
 139     info->mode = sc->mode;
 140     info->initial_count = sc->count;
 141     info->out = pit_get_out(sc, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
 142 }
 143
 144 void pit_get_channel_info(ISADevice *dev, int channel, PITChannelInfo *info)
 145 {
 146     PITCommonState *pit = PIT_COMMON(dev);
 147     PITChannelState *s = &pit->channels[channel];
 148     PITCommonClass *c = PIT_COMMON_GET_CLASS(pit);
 149
 150     c->get_channel_info(pit, s, info);
 151 }
 152
 153 void pit_reset_common(PITCommonState *pit)
 154 {
 155     PITChannelState *s;
 156     int i;
 157
 158     for (i = 0; i < 3; i++) {
 159         s = &pit->channels[i];
 160         s->mode = 3;
 161         s->gate = (i != 2);
 162         s->count_load_time = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
 163         s->count = 0x10000;
 164         if (i == 0 && !s->irq_disabled) {
 165             s->next_transition_time =
 166                 pit_get_next_transition_time(s, s->count_load_time);
 167         }
 168     }
 169 }
 170
 171 static void pit_common_realize(DeviceState *dev, Error **errp)
 172 {
 173     ISADevice *isadev = ISA_DEVICE(dev);
 174     PITCommonState *pit = PIT_COMMON(dev);
 175
 176     isa_register_ioport(isadev, &pit->ioports, pit->iobase);
 177
 178     qdev_set_legacy_instance_id(dev, pit->iobase, 2);
 179 }
 180
 181 static const VMStateDescription vmstate_pit_channel = {
 182     .name = "pit channel",
 183     .version_id = 2,
 184     .minimum_version_id = 2,
 185     .fields = (VMStateField[]) {
 186         VMSTATE_INT32(count, PITChannelState),
 187         VMSTATE_UINT16(latched_count, PITChannelState),
 188         VMSTATE_UINT8(count_latched, PITChannelState),
 189         VMSTATE_UINT8(status_latched, PITChannelState),
 190         VMSTATE_UINT8(status, PITChannelState),
 191         VMSTATE_UINT8(read_state, PITChannelState),
 192         VMSTATE_UINT8(write_state, PITChannelState),
 193         VMSTATE_UINT8(write_latch, PITChannelState),
 194         VMSTATE_UINT8(rw_mode, PITChannelState),
 195         VMSTATE_UINT8(mode, PITChannelState),
 196         VMSTATE_UINT8(bcd, PITChannelState),
 197         VMSTATE_UINT8(gate, PITChannelState),
 198         VMSTATE_INT64(count_load_time, PITChannelState),
 199         VMSTATE_INT64(next_transition_time, PITChannelState),
 200         VMSTATE_END_OF_LIST()
 201     }
 202 };
 203
 204 static int pit_dispatch_pre_save(void *opaque)
 205 {
 206     PITCommonState *s = opaque;
 207     PITCommonClass *c = PIT_COMMON_GET_CLASS(s);
 208
 209     if (c->pre_save) {
 210         c->pre_save(s);
 211     }
 212
 213     return 0;
 214 }
 215
 216 static int pit_dispatch_post_load(void *opaque, int version_id)
 217 {
 218     PITCommonState *s = opaque;
 219     PITCommonClass *c = PIT_COMMON_GET_CLASS(s);
 220
 221     if (c->post_load) {
 222         c->post_load(s);
 223     }
 224     return 0;
 225 }
 226
 227 static const VMStateDescription vmstate_pit_common = {
 228     .name = "i8254",
 229     .version_id = 3,
 230     .minimum_version_id = 2,
 231     .pre_save = pit_dispatch_pre_save,
 232     .post_load = pit_dispatch_post_load,
 233     .fields = (VMStateField[]) {
 234         VMSTATE_UINT32_V(channels[0].irq_disabled, PITCommonState, 3),
 235         VMSTATE_STRUCT_ARRAY(channels, PITCommonState, 3, 2,
 236                              vmstate_pit_channel, PITChannelState),
 237         VMSTATE_INT64(channels[0].next_transition_time,
 238                       PITCommonState), /* formerly irq_timer */
 239         VMSTATE_END_OF_LIST()
 240     }
 241 };
 242
 243 static void pit_common_class_init(ObjectClass *klass, void *data)
 244 {
 245     DeviceClass *dc = DEVICE_CLASS(klass);
 246
 247     dc->realize = pit_common_realize;
 248     dc->vmsd = &vmstate_pit_common;
 249     /*
 250      * Reason: unlike ordinary ISA devices, the PIT may need to be
 251      * wired to the HPET, and because of that, some wiring is always
 252      * done by board code.
 253      */
 254     dc->user_creatable = false;
 255 }
 256
 257 static const TypeInfo pit_common_type = {
 258     .name          = TYPE_PIT_COMMON,
 259     .parent        = TYPE_ISA_DEVICE,
 260     .instance_size = sizeof(PITCommonState),
 261     .class_size    = sizeof(PITCommonClass),
 262     .class_init    = pit_common_class_init,
 263     .abstract      = true,
 264 };
 265
 266 static void register_devices(void)
 267 {
 268     type_register_static(&pit_common_type);
 269 }
 270
 271 type_init(register_devices);