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