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        spi_claim_bus(slave);
  48
  49        /* command */
  50        if(spi_xfer(slave, 8, &cmd, NULL, SPI_XFER_BEGIN))
  51                return -1;
  52
  53        /*
  54         * if alen == 3, addr[0] is the block number, we never use it here. All we
  55         * need are the lower 16 bits
  56         */
  57        if (alen == 3)
  58                addr++;
  59
  60        /* address, and data */
  61        if(spi_xfer(slave, 16, addr, NULL, 0))
  62                return -1;
  63        if(spi_xfer(slave, 8 * len, NULL, buffer, SPI_XFER_END))
  64                return -1;
  65
  66        spi_release_bus(slave);
  67        spi_free_slave(slave);
  68        return len;
  69}
  70
  71ssize_t spi_write (uchar *addr, int alen, uchar *buffer, int len)
  72{
  73        struct spi_slave *slave;
  74        char buf[3];
  75
  76        slave = spi_setup_slave(CONFIG_DEFAULT_SPI_BUS, 1, 1000000,
  77                        CONFIG_DEFAULT_SPI_MODE);
  78        spi_claim_bus(slave);
  79
  80        buf[0] = SPI_EEPROM_WREN;
  81        if(spi_xfer(slave, 8, buf, NULL, SPI_XFER_BEGIN | SPI_XFER_END))
  82                return -1;
  83
  84        buf[0] = SPI_EEPROM_WRITE;
  85
  86        /* As for reading, drop addr[0] if alen is 3 */
  87        if (alen == 3) {
  88                alen--;
  89                addr++;
  90        }
  91
  92        memcpy(buf + 1, addr, alen);
  93        /* command + addr, then data */
  94        if(spi_xfer(slave, 24, buf, NULL, SPI_XFER_BEGIN))
  95                return -1;
  96        if(spi_xfer(slave, len * 8, buffer, NULL, SPI_XFER_END))
  97                return -1;
  98
  99        reset_timer_masked();
 100        do {
 101                buf[0] = SPI_EEPROM_RDSR;
 102                buf[1] = 0;
 103                spi_xfer(slave, 16, buf, buf, SPI_XFER_BEGIN | SPI_XFER_END);
 104
 105                if (!(buf[1] & 1))
 106                        break;
 107
 108        } while (get_timer_masked() < CONFIG_SYS_SPI_WRITE_TOUT);
 109
 110        if (buf[1] & 1)
 111                printf ("*** spi_write: Time out while writing!\n");
 112
 113        spi_release_bus(slave);
 114        spi_free_slave(slave);
 115        return len;
 116}
 117