LXR uboot/drivers/mtd/spi/eeprom

   1/*
   2 * Copyright (C) 2009
   3 * Albin Tonnerre, Free Electrons <albin.tonnerre@free-electrons.com>
   4 *
   5 * See file CREDITS for list of people who contributed to this
   6 * project.
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public License as
  10 * published by the Free Software Foundation; either version 2 of
  11 * the License, or (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  21 * MA 02111-1307 USA
  22 */
  23
  24#include <common.h>
  25#include <spi.h>
  26
  27#define SPI_EEPROM_WREN         0x06
  28#define SPI_EEPROM_RDSR         0x05
  29#define SPI_EEPROM_READ         0x03
  30#define SPI_EEPROM_WRITE        0x02
  31
  32#ifndef CONFIG_DEFAULT_SPI_BUS
  33#define CONFIG_DEFAULT_SPI_BUS 0
  34#endif
  35
  36#ifndef CONFIG_DEFAULT_SPI_MODE
  37#define CONFIG_DEFAULT_SPI_MODE SPI_MODE_0
  38#endif
  39
  40ssize_t spi_read (uchar *addr, int alen, uchar *buffer, int len)
  41{
  42        struct spi_slave *slave;
  43        u8 cmd = SPI_EEPROM_READ;
  44
  45        slave = spi_setup_slave(CONFIG_DEFAULT_SPI_BUS, 1, 1000000,
  46                        CONFIG_DEFAULT_SPI_MODE);
  47        if(!slave)
  48                return 0;
  49
  50        spi_claim_bus(slave);
  51
  52        /* command */
  53        if(spi_xfer(slave, 8, &cmd, NULL, SPI_XFER_BEGIN))
  54                return -1;
  55
  56        /*
  57         * if alen == 3, addr[0] is the block number, we never use it here. All we
  58         * need are the lower 16 bits
  59         */
  60        if (alen == 3)
  61                addr++;
  62
  63        /* address, and data */
  64        if(spi_xfer(slave, 16, addr, NULL, 0))
  65                return -1;
  66        if(spi_xfer(slave, 8 * len, NULL, buffer, SPI_XFER_END))
  67                return -1;
  68
  69        spi_release_bus(slave);
  70        spi_free_slave(slave);
  71        return len;
  72}
  73
  74ssize_t spi_write (uchar *addr, int alen, uchar *buffer, int len)
  75{
  76        struct spi_slave *slave;
  77        char buf[3];
  78        ulong start;
  79
  80        slave = spi_setup_slave(CONFIG_DEFAULT_SPI_BUS, 1, 1000000,
  81                        CONFIG_DEFAULT_SPI_MODE);
  82        if (!slave)
  83                return 0;
  84
  85        spi_claim_bus(slave);
  86
  87        buf[0] = SPI_EEPROM_WREN;
  88        if(spi_xfer(slave, 8, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END))
  89                return -1;
  90
  91        buf[0] = SPI_EEPROM_WRITE;
  92
  93        /* As for reading, drop addr[0] if alen is 3 */
  94        if (alen == 3) {
  95                alen--;
  96                addr++;
  97        }
  98
  99        memcpy(buf + 1, addr, alen);
 100        /* command + addr, then data */
 101        if(spi_xfer(slave, 24, buf, NULL, SPI_XFER_BEGIN))
 102                return -1;
 103        if(spi_xfer(slave, len * 8, buffer, NULL, SPI_XFER_END))
 104                return -1;
 105
 106        start = get_timer(0);
 107        do {
 108                buf[0] = SPI_EEPROM_RDSR;
 109                buf[1] = 0;
 110                spi_xfer(slave, 16, buf, buf, SPI_XFER_BEGIN | SPI_XFER_END);
 111
 112                if (!(buf[1] & 1))
 113                        break;
 114
 115        } while (get_timer(start) < CONFIG_SYS_SPI_WRITE_TOUT);
 116
 117        if (buf[1] & 1)
 118                printf ("*** spi_write: Time out while writing!\n");
 119
 120        spi_release_bus(slave);
 121        spi_free_slave(slave);
 122        return len;
 123}
 124