mcf5206elite/nvram/nvram.c

0001 /*
0002  * DS1307-based Non-Volatile memory device driver
0003  *
0004  * DS1307 chip is a I2C Real-Time Clock. It contains 56 bytes of
0005  * non-volatile RAM storage. This driver provide file-like interface to
0006  * this memory.
0007  *
0008  * Copyright (C) 2000 OKTET Ltd., St.-Petersburg, Russia
0009  * Author: Victor V. Vengerov <vvv@oktet.ru>
0010  *
0011  * The license and distribution terms for this file may be
0012  * found in the file LICENSE in this distribution or at
0013  *
0014  * http://www.rtems.org/license/LICENSE.
0015  */
0016
0017 #include <rtems.h>
0018 #include <rtems/libio.h>
0019 #include <errno.h>
0020 #include <string.h>
0021 #include <bsp.h>
0022 #include <nvram.h>
0023 #include <i2c.h>
0024 #include <ds1307.h>
0025
0026 /* nvram_driver_initialize --
0027  *     Non-volatile memory device driver initialization.
0028  */
0029 rtems_device_driver
0030 nvram_driver_initialize(rtems_device_major_number major,
0031                         rtems_device_minor_number minor,
0032                         void *arg)
0033 {
0034     rtems_status_code sc;
0035     i2c_message_status status;
0036     i2c_bus_number bus = DS1307_I2C_BUS_NUMBER;
0037     i2c_address    addr = DS1307_I2C_ADDRESS;
0038     int try = 0;
0039     do {
0040         status = i2c_wrbyte(bus, addr, 0);
0041         if (status == I2C_NO_DEVICE)
0042             break;
0043         try++;
0044     } while ((try < 15) && (status != I2C_SUCCESSFUL));
0045
0046     if (status == I2C_SUCCESSFUL)
0047     {
0048         sc = rtems_io_register_name("/dev/nvram", major, 0);
0049         if (sc != RTEMS_SUCCESSFUL)
0050         {
0051             errno = EIO;
0052             return RTEMS_UNSATISFIED;
0053         }
0054         else
0055             return RTEMS_SUCCESSFUL;
0056     }
0057     else
0058     {
0059         errno = ENODEV;
0060         return RTEMS_UNSATISFIED;
0061     }
0062 }
0063
0064 /* nvram_driver_open --
0065  *     Non-volatile memory device driver open primitive.
0066  */
0067 rtems_device_driver
0068 nvram_driver_open(rtems_device_major_number major,
0069                   rtems_device_minor_number minor,
0070                   void *arg)
0071 {
0072     return RTEMS_SUCCESSFUL;
0073 }
0074
0075 /* nvram_driver_close --
0076  *     Non-volatile memory device driver close primitive.
0077  */
0078 rtems_device_driver
0079 nvram_driver_close(rtems_device_major_number major,
0080                    rtems_device_minor_number minor,
0081                    void *arg)
0082 {
0083     return RTEMS_SUCCESSFUL;
0084 }
0085
0086 /* nvram_driver_read --
0087  *     Non-volatile memory device driver read primitive.
0088  */
0089 rtems_device_driver
0090 nvram_driver_read(rtems_device_major_number major,
0091                   rtems_device_minor_number minor,
0092                   void *arg)
0093 {
0094     rtems_libio_rw_args_t *args = arg;
0095     uint32_t   count;
0096     i2c_bus_number bus = DS1307_I2C_BUS_NUMBER;
0097     i2c_address    addr = DS1307_I2C_ADDRESS;
0098     i2c_message_status status;
0099     if (args->offset >= DS1307_NVRAM_SIZE)
0100     {
0101         count = 0;
0102     }
0103     else if (args->offset + args->count >= DS1307_NVRAM_SIZE)
0104     {
0105         count = DS1307_NVRAM_SIZE - args->offset;
0106     }
0107     else
0108     {
0109         count = args->count;
0110     }
0111     if (count > 0)
0112     {
0113         int try = 0;
0114         do {
0115             status = i2c_wbrd(bus, addr, DS1307_NVRAM_START + args->offset,
0116                               args->buffer, count);
0117             try++;
0118         } while ((try < 15) && (status != I2C_SUCCESSFUL));
0119         if (status != I2C_SUCCESSFUL)
0120         {
0121             errno = EIO;
0122             return RTEMS_UNSATISFIED;
0123         }
0124     }
0125     args->bytes_moved = count;
0126     return RTEMS_SUCCESSFUL;
0127 }
0128
0129 /* nvram_driver_write --
0130  *     Non-volatile memory device driver write primitive.
0131  */
0132 rtems_device_driver
0133 nvram_driver_write(rtems_device_major_number major,
0134                    rtems_device_minor_number minor,
0135                    void *arg)
0136 {
0137     rtems_libio_rw_args_t *args = arg;
0138     uint32_t   count;
0139     i2c_bus_number bus = DS1307_I2C_BUS_NUMBER;
0140     i2c_address    addr = DS1307_I2C_ADDRESS;
0141     i2c_message_status status;
0142
0143     if (args->offset >= DS1307_NVRAM_SIZE)
0144     {
0145         count = 0;
0146     }
0147     else if (args->offset + args->count >= DS1307_NVRAM_SIZE)
0148     {
0149         count = DS1307_NVRAM_SIZE - args->offset;
0150     }
0151     else
0152     {
0153         count = args->count;
0154     }
0155     if (count > 0)
0156     {
0157         int try = 0;
0158         do {
0159             uint8_t         buf[DS1307_NVRAM_SIZE + 1];
0160             buf[0] = DS1307_NVRAM_START + args->offset;
0161             memcpy(buf+1, args->buffer, count);
0162             status = i2c_write(bus, addr, buf, count+1);
0163             try++;
0164         } while ((try < 15) && (status != I2C_SUCCESSFUL));
0165         if (status != I2C_SUCCESSFUL)
0166         {
0167             errno = EIO;
0168             return RTEMS_UNSATISFIED;
0169         }
0170     }
0171     args->bytes_moved = count;
0172     return RTEMS_SUCCESSFUL;
0173 }