hw/rtc/ds1338.c - qemu - Git at Google

 /*
  * 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 "qemu/osdep.h"
 #include "hw/i2c/i2c.h"
 #include "migration/vmstate.h"
 #include "qemu/bcd.h"
 #include "qemu/module.h"
 #include "qom/object.h"
 #include "sysemu/rtc.h"
 #include "trace.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

 #define TYPE_DS1338 "ds1338"
 OBJECT_DECLARE_SIMPLE_TYPE(DS1338State, DS1338)

 struct DS1338State {
     I2CSlave parent_obj;

     int64_t offset;
     uint8_t wday_offset;
     uint8_t nvram[NVRAM_SIZE];
     int32_t ptr;
     bool addr_byte;
 };

 static const VMStateDescription vmstate_ds1338 = {
     .name = "ds1338",
     .version_id = 2,
     .minimum_version_id = 1,
     .fields = (const VMStateField[]) {
         VMSTATE_I2C_SLAVE(parent_obj, 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 int ds1338_event(I2CSlave *i2c, enum i2c_event event)
 {
     DS1338State *s = DS1338(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;
     }

     return 0;
 }

 static uint8_t ds1338_recv(I2CSlave *i2c)
 {
     DS1338State *s = DS1338(i2c);
     uint8_t res;

     res  = s->nvram[s->ptr];

     trace_ds1338_recv(s->ptr, res);

     inc_regptr(s);
     return res;
 }

 static int ds1338_send(I2CSlave *i2c, uint8_t data)
 {
     DS1338State *s = DS1338(i2c);

     trace_ds1338_send(s->ptr, data);

     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 void ds1338_reset(DeviceState *dev)
 {
     DS1338State *s = DS1338(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->event = ds1338_event;
     k->recv = ds1338_recv;
     k->send = ds1338_send;
     device_class_set_legacy_reset(dc, ds1338_reset);
     dc->vmsd = &vmstate_ds1338;
 }

 static const TypeInfo ds1338_info = {
     .name          = TYPE_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)
	/*
	* 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 "qemu/osdep.h"
	#include "hw/i2c/i2c.h"
	#include "migration/vmstate.h"
	#include "qemu/bcd.h"
	#include "qemu/module.h"
	#include "qom/object.h"
	#include "sysemu/rtc.h"
	#include "trace.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

	#define TYPE_DS1338 "ds1338"
	OBJECT_DECLARE_SIMPLE_TYPE(DS1338State, DS1338)

	struct DS1338State {
	I2CSlave parent_obj;

	int64_t offset;
	uint8_t wday_offset;
	uint8_t nvram[NVRAM_SIZE];
	int32_t ptr;
	bool addr_byte;
	};

	static const VMStateDescription vmstate_ds1338 = {
	.name = "ds1338",
	.version_id = 2,
	.minimum_version_id = 1,
	.fields = (const VMStateField[]) {
	VMSTATE_I2C_SLAVE(parent_obj, 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 int ds1338_event(I2CSlave *i2c, enum i2c_event event)
	{
	DS1338State *s = DS1338(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;
	}

	return 0;
	}

	static uint8_t ds1338_recv(I2CSlave *i2c)
	{
	DS1338State *s = DS1338(i2c);
	uint8_t res;

	res = s->nvram[s->ptr];

	trace_ds1338_recv(s->ptr, res);

	inc_regptr(s);
	return res;
	}

	static int ds1338_send(I2CSlave *i2c, uint8_t data)
	{
	DS1338State *s = DS1338(i2c);

	trace_ds1338_send(s->ptr, data);

	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 void ds1338_reset(DeviceState *dev)
	{
	DS1338State *s = DS1338(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->event = ds1338_event;
	k->recv = ds1338_recv;
	k->send = ds1338_send;
	device_class_set_legacy_reset(dc, ds1338_reset);
	dc->vmsd = &vmstate_ds1338;
	}

	static const TypeInfo ds1338_info = {
	.name = TYPE_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)