hw/timer/m41t80.c

   1 /*
   2  * M41T80 serial rtc emulation
   3  *
   4  * Copyright (c) 2018 BALATON Zoltan
   5  *
   6  * This work is licensed under the GNU GPL license version 2 or later.
   7  *
   8  */
   9
  10 #include "qemu/osdep.h"
  11 #include "qemu/log.h"
  12 #include "qemu/timer.h"
  13 #include "qemu/bcd.h"
  14 #include "hw/i2c/i2c.h"
  15
  16 #define TYPE_M41T80 "m41t80"
  17 #define M41T80(obj) OBJECT_CHECK(M41t80State, (obj), TYPE_M41T80)
  18
  19 typedef struct M41t80State {
  20     I2CSlave parent_obj;
  21     int8_t addr;
  22 } M41t80State;
  23
  24 static void m41t80_realize(DeviceState *dev, Error **errp)
  25 {
  26     M41t80State *s = M41T80(dev);
  27
  28     s->addr = -1;
  29 }
  30
  31 static int m41t80_send(I2CSlave *i2c, uint8_t data)
  32 {
  33     M41t80State *s = M41T80(i2c);
  34
  35     if (s->addr < 0) {
  36         s->addr = data;
  37     } else {
  38         s->addr++;
  39     }
  40     return 0;
  41 }
  42
  43 static int m41t80_recv(I2CSlave *i2c)
  44 {
  45     M41t80State *s = M41T80(i2c);
  46     struct tm now;
  47     qemu_timeval tv;
  48
  49     if (s->addr < 0) {
  50         s->addr = 0;
  51     }
  52     if (s->addr >= 1 && s->addr <= 7) {
  53         qemu_get_timedate(&now, -1);
  54     }
  55     switch (s->addr++) {
  56     case 0:
  57         qemu_gettimeofday(&tv);
  58         return to_bcd(tv.tv_usec / 10000);
  59     case 1:
  60         return to_bcd(now.tm_sec);
  61     case 2:
  62         return to_bcd(now.tm_min);
  63     case 3:
  64         return to_bcd(now.tm_hour);
  65     case 4:
  66         return to_bcd(now.tm_wday);
  67     case 5:
  68         return to_bcd(now.tm_mday);
  69     case 6:
  70         return to_bcd(now.tm_mon + 1);
  71     case 7:
  72         return to_bcd(now.tm_year % 100);
  73     case 8 ... 19:
  74         qemu_log_mask(LOG_UNIMP, "%s: unimplemented register: %d\n",
  75                       __func__, s->addr - 1);
  76         return 0;
  77     default:
  78         qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid register: %d\n",
  79                       __func__, s->addr - 1);
  80         return 0;
  81     }
  82 }
  83
  84 static int m41t80_event(I2CSlave *i2c, enum i2c_event event)
  85 {
  86     M41t80State *s = M41T80(i2c);
  87
  88     if (event == I2C_START_SEND) {
  89         s->addr = -1;
  90     }
  91     return 0;
  92 }
  93
  94 static void m41t80_class_init(ObjectClass *klass, void *data)
  95 {
  96     DeviceClass *dc = DEVICE_CLASS(klass);
  97     I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
  98
  99     dc->realize = m41t80_realize;
 100     sc->send = m41t80_send;
 101     sc->recv = m41t80_recv;
 102     sc->event = m41t80_event;
 103 }
 104
 105 static const TypeInfo m41t80_info = {
 106     .name          = TYPE_M41T80,
 107     .parent        = TYPE_I2C_SLAVE,
 108     .instance_size = sizeof(M41t80State),
 109     .class_init    = m41t80_class_init,
 110 };
 111
 112 static void m41t80_register_types(void)
 113 {
 114     type_register_static(&m41t80_info);
 115 }
 116
 117 type_init(m41t80_register_types)