| /* |
| * MAXIM DS1338 I2C RTC+NVRAM |
| * |
| * Copyright (c) 2009 CodeSourcery. |
| * Written by Paul Brook |
| * |
| * This code is licensed under the GNU GPL v2. |
| * |
| * Contributions after 2012-01-13 are licensed under the terms of the |
| * GNU GPL, version 2 or (at your option) any later version. |
| */ |
| |
| #include "hw/i2c.h" |
| |
| /* Size of NVRAM including both the user-accessible area and the |
| * secondary register area. |
| */ |
| #define NVRAM_SIZE 64 |
| |
| /* Flags definitions */ |
| #define SECONDS_CH 0x80 |
| #define HOURS_12 0x40 |
| #define HOURS_PM 0x20 |
| #define CTRL_OSF 0x20 |
| |
| typedef struct { |
| I2CSlave i2c; |
| int64_t offset; |
| uint8_t wday_offset; |
| uint8_t nvram[NVRAM_SIZE]; |
| int32_t ptr; |
| bool addr_byte; |
| } DS1338State; |
| |
| static const VMStateDescription vmstate_ds1338 = { |
| .name = "ds1338", |
| .version_id = 2, |
| .minimum_version_id = 1, |
| .minimum_version_id_old = 1, |
| .fields = (VMStateField[]) { |
| VMSTATE_I2C_SLAVE(i2c, DS1338State), |
| VMSTATE_INT64(offset, DS1338State), |
| VMSTATE_UINT8_V(wday_offset, DS1338State, 2), |
| VMSTATE_UINT8_ARRAY(nvram, DS1338State, NVRAM_SIZE), |
| VMSTATE_INT32(ptr, DS1338State), |
| VMSTATE_BOOL(addr_byte, DS1338State), |
| VMSTATE_END_OF_LIST() |
| } |
| }; |
| |
| static void capture_current_time(DS1338State *s) |
| { |
| /* Capture the current time into the secondary registers |
| * which will be actually read by the data transfer operation. |
| */ |
| struct tm now; |
| qemu_get_timedate(&now, s->offset); |
| s->nvram[0] = to_bcd(now.tm_sec); |
| s->nvram[1] = to_bcd(now.tm_min); |
| if (s->nvram[2] & HOURS_12) { |
| int tmp = now.tm_hour; |
| if (tmp % 12 == 0) { |
| tmp += 12; |
| } |
| if (tmp <= 12) { |
| s->nvram[2] = HOURS_12 | to_bcd(tmp); |
| } else { |
| s->nvram[2] = HOURS_12 | HOURS_PM | to_bcd(tmp - 12); |
| } |
| } else { |
| s->nvram[2] = to_bcd(now.tm_hour); |
| } |
| s->nvram[3] = (now.tm_wday + s->wday_offset) % 7 + 1; |
| s->nvram[4] = to_bcd(now.tm_mday); |
| s->nvram[5] = to_bcd(now.tm_mon + 1); |
| s->nvram[6] = to_bcd(now.tm_year - 100); |
| } |
| |
| static void inc_regptr(DS1338State *s) |
| { |
| /* The register pointer wraps around after 0x3F; wraparound |
| * causes the current time/date to be retransferred into |
| * the secondary registers. |
| */ |
| s->ptr = (s->ptr + 1) & (NVRAM_SIZE - 1); |
| if (!s->ptr) { |
| capture_current_time(s); |
| } |
| } |
| |
| static void ds1338_event(I2CSlave *i2c, enum i2c_event event) |
| { |
| DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c); |
| |
| switch (event) { |
| case I2C_START_RECV: |
| /* In h/w, capture happens on any START condition, not just a |
| * START_RECV, but there is no need to actually capture on |
| * START_SEND, because the guest can't get at that data |
| * without going through a START_RECV which would overwrite it. |
| */ |
| capture_current_time(s); |
| break; |
| case I2C_START_SEND: |
| s->addr_byte = true; |
| break; |
| default: |
| break; |
| } |
| } |
| |
| static int ds1338_recv(I2CSlave *i2c) |
| { |
| DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c); |
| uint8_t res; |
| |
| res = s->nvram[s->ptr]; |
| inc_regptr(s); |
| return res; |
| } |
| |
| static int ds1338_send(I2CSlave *i2c, uint8_t data) |
| { |
| DS1338State *s = FROM_I2C_SLAVE(DS1338State, i2c); |
| if (s->addr_byte) { |
| s->ptr = data & (NVRAM_SIZE - 1); |
| s->addr_byte = false; |
| return 0; |
| } |
| if (s->ptr < 7) { |
| /* Time register. */ |
| struct tm now; |
| qemu_get_timedate(&now, s->offset); |
| switch(s->ptr) { |
| case 0: |
| /* TODO: Implement CH (stop) bit. */ |
| now.tm_sec = from_bcd(data & 0x7f); |
| break; |
| case 1: |
| now.tm_min = from_bcd(data & 0x7f); |
| break; |
| case 2: |
| if (data & HOURS_12) { |
| int tmp = from_bcd(data & (HOURS_PM - 1)); |
| if (data & HOURS_PM) { |
| tmp += 12; |
| } |
| if (tmp % 12 == 0) { |
| tmp -= 12; |
| } |
| now.tm_hour = tmp; |
| } else { |
| now.tm_hour = from_bcd(data & (HOURS_12 - 1)); |
| } |
| break; |
| case 3: |
| { |
| /* The day field is supposed to contain a value in |
| the range 1-7. Otherwise behavior is undefined. |
| */ |
| int user_wday = (data & 7) - 1; |
| s->wday_offset = (user_wday - now.tm_wday + 7) % 7; |
| } |
| break; |
| case 4: |
| now.tm_mday = from_bcd(data & 0x3f); |
| break; |
| case 5: |
| now.tm_mon = from_bcd(data & 0x1f) - 1; |
| break; |
| case 6: |
| now.tm_year = from_bcd(data) + 100; |
| break; |
| } |
| s->offset = qemu_timedate_diff(&now); |
| } else if (s->ptr == 7) { |
| /* Control register. */ |
| |
| /* Ensure bits 2, 3 and 6 will read back as zero. */ |
| data &= 0xB3; |
| |
| /* Attempting to write the OSF flag to logic 1 leaves the |
| value unchanged. */ |
| data = (data & ~CTRL_OSF) | (data & s->nvram[s->ptr] & CTRL_OSF); |
| |
| s->nvram[s->ptr] = data; |
| } else { |
| s->nvram[s->ptr] = data; |
| } |
| inc_regptr(s); |
| return 0; |
| } |
| |
| static int ds1338_init(I2CSlave *i2c) |
| { |
| return 0; |
| } |
| |
| static void ds1338_reset(DeviceState *dev) |
| { |
| DS1338State *s = FROM_I2C_SLAVE(DS1338State, I2C_SLAVE(dev)); |
| |
| /* The clock is running and synchronized with the host */ |
| s->offset = 0; |
| s->wday_offset = 0; |
| memset(s->nvram, 0, NVRAM_SIZE); |
| s->ptr = 0; |
| s->addr_byte = false; |
| } |
| |
| static void ds1338_class_init(ObjectClass *klass, void *data) |
| { |
| DeviceClass *dc = DEVICE_CLASS(klass); |
| I2CSlaveClass *k = I2C_SLAVE_CLASS(klass); |
| |
| k->init = ds1338_init; |
| k->event = ds1338_event; |
| k->recv = ds1338_recv; |
| k->send = ds1338_send; |
| dc->reset = ds1338_reset; |
| dc->vmsd = &vmstate_ds1338; |
| } |
| |
| static const TypeInfo ds1338_info = { |
| .name = "ds1338", |
| .parent = TYPE_I2C_SLAVE, |
| .instance_size = sizeof(DS1338State), |
| .class_init = ds1338_class_init, |
| }; |
| |
| static void ds1338_register_types(void) |
| { |
| type_register_static(&ds1338_info); |
| } |
| |
| type_init(ds1338_register_types) |