/*
* DS1307-based Non-Volatile memory device driver
*
* DS1307 chip is a I2C Real-Time Clock. It contains 56 bytes of
* non-volatile RAM storage. This driver provide file-like interface to
* this memory.
*
* Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia
* Author: Victor V. Vengerov <vvv@oktet.ru>
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
*
* http://www.rtems.com/license/LICENSE.
*
* @(#) $Id$
*/
#include <rtems.h>
#include <rtems/libio.h>
#include <errno.h>
#include <string.h>
#include <bsp.h>
#include <nvram.h>
#include <i2c.h>
#include <ds1307.h>
/* nvram_driver_initialize --
* Non-volatile memory device driver initialization.
*/
rtems_device_driver
nvram_driver_initialize(rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg)
{
rtems_status_code sc;
i2c_message_status status;
i2c_bus_number bus = DS1307_I2C_BUS_NUMBER;
i2c_address addr = DS1307_I2C_ADDRESS;
int try = 0;
do {
status = i2c_wrbyte(bus, addr, 0);
if (status == I2C_NO_DEVICE)
break;
try++;
} while ((try < 15) && (status != I2C_SUCCESSFUL));
if (status == I2C_SUCCESSFUL)
{
sc = rtems_io_register_name("/dev/nvram", major, 0);
if (sc != RTEMS_SUCCESSFUL)
{
errno = EIO;
return RTEMS_UNSATISFIED;
}
else
return RTEMS_SUCCESSFUL;
}
else
{
errno = ENODEV;
return RTEMS_UNSATISFIED;
}
}
/* nvram_driver_open --
* Non-volatile memory device driver open primitive.
*/
rtems_device_driver
nvram_driver_open(rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg)
{
return RTEMS_SUCCESSFUL;
}
/* nvram_driver_close --
* Non-volatile memory device driver close primitive.
*/
rtems_device_driver
nvram_driver_close(rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg)
{
return RTEMS_SUCCESSFUL;
}
/* nvram_driver_read --
* Non-volatile memory device driver read primitive.
*/
rtems_device_driver
nvram_driver_read(rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg)
{
rtems_libio_rw_args_t *args = arg;
uint32_t count;
i2c_bus_number bus = DS1307_I2C_BUS_NUMBER;
i2c_address addr = DS1307_I2C_ADDRESS;
i2c_message_status status;
if (args->offset >= DS1307_NVRAM_SIZE)
{
count = 0;
}
else if (args->offset + args->count >= DS1307_NVRAM_SIZE)
{
count = DS1307_NVRAM_SIZE - args->offset;
}
else
{
count = args->count;
}
if (count > 0)
{
int try = 0;
do {
status = i2c_wbrd(bus, addr, DS1307_NVRAM_START + args->offset,
args->buffer, count);
try++;
} while ((try < 15) && (status != I2C_SUCCESSFUL));
if (status != I2C_SUCCESSFUL)
{
errno = EIO;
return RTEMS_UNSATISFIED;
}
}
args->bytes_moved = count;
return RTEMS_SUCCESSFUL;
}
/* nvram_driver_write --
* Non-volatile memory device driver write primitive.
*/
rtems_device_driver
nvram_driver_write(rtems_device_major_number major,
rtems_device_minor_number minor,
void *arg)
{
rtems_libio_rw_args_t *args = arg;
uint32_t count;
i2c_bus_number bus = DS1307_I2C_BUS_NUMBER;
i2c_address addr = DS1307_I2C_ADDRESS;
i2c_message_status status;
if (args->offset >= DS1307_NVRAM_SIZE)
{
count = 0;
}
else if (args->offset + args->count >= DS1307_NVRAM_SIZE)
{
count = DS1307_NVRAM_SIZE - args->offset;
}
else
{
count = args->count;
}
if (count > 0)
{
int try = 0;
do {
uint8_t buf[DS1307_NVRAM_SIZE + 1];
buf[0] = DS1307_NVRAM_START + args->offset;
memcpy(buf+1, args->buffer, count);
status = i2c_write(bus, addr, buf, count+1);
try++;
} while ((try < 15) && (status != I2C_SUCCESSFUL));
if (status != I2C_SUCCESSFUL)
{
errno = EIO;
return RTEMS_UNSATISFIED;
}
}
args->bytes_moved = count;
return RTEMS_SUCCESSFUL;
}
