mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-18 17:54:13 +08:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
172 lines
3.6 KiB
C
172 lines
3.6 KiB
C
/*
|
|
* arch/mips/pmc-sierra/yosemite/atmel_read_eeprom.c
|
|
*
|
|
* Copyright (C) 2003 PMC-Sierra Inc.
|
|
* Author: Manish Lachwani (lachwani@pmc-sierra.com)
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
|
|
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN
|
|
* NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
|
* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
|
|
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
* You should have received a copy of the GNU General Public License along
|
|
* with this program; if not, write to the Free Software Foundation, Inc.,
|
|
* 675 Mass Ave, Cambridge, MA 02139, USA.
|
|
*/
|
|
|
|
/*
|
|
* Description:
|
|
*
|
|
* This code reads the ATMEL 24CXX EEPROM. The PMC-Sierra Yosemite board uses the ATMEL
|
|
* 24C32/24C64 which uses two byte addressing as compared to 24C16. Note that this program
|
|
* uses the serial port like /dev/ttyS0, to communicate with the EEPROM. Hence, you are
|
|
* expected to have a connectivity from the EEPROM to the serial port. This program does
|
|
* __not__ communicate using the I2C protocol
|
|
*/
|
|
|
|
#include "atmel_read_eeprom.h"
|
|
|
|
static void delay(int delay)
|
|
{
|
|
while (delay--);
|
|
}
|
|
|
|
static void send_bit(unsigned char bit)
|
|
{
|
|
scl_lo;
|
|
delay(TXX);
|
|
if (bit)
|
|
sda_hi;
|
|
else
|
|
sda_lo;
|
|
|
|
delay(TXX);
|
|
scl_hi;
|
|
delay(TXX);
|
|
}
|
|
|
|
static void send_ack(void)
|
|
{
|
|
send_bit(0);
|
|
}
|
|
|
|
static void send_byte(unsigned char byte)
|
|
{
|
|
int i = 0;
|
|
|
|
for (i = 7; i >= 0; i--)
|
|
send_bit((byte >> i) & 0x01);
|
|
}
|
|
|
|
static void send_start(void)
|
|
{
|
|
sda_hi;
|
|
delay(TXX);
|
|
scl_hi;
|
|
delay(TXX);
|
|
sda_lo;
|
|
delay(TXX);
|
|
}
|
|
|
|
static void send_stop(void)
|
|
{
|
|
sda_lo;
|
|
delay(TXX);
|
|
scl_hi;
|
|
delay(TXX);
|
|
sda_hi;
|
|
delay(TXX);
|
|
}
|
|
|
|
static void do_idle(void)
|
|
{
|
|
sda_hi;
|
|
scl_hi;
|
|
vcc_off;
|
|
}
|
|
|
|
static int recv_bit(void)
|
|
{
|
|
int status;
|
|
|
|
scl_lo;
|
|
delay(TXX);
|
|
sda_hi;
|
|
delay(TXX);
|
|
scl_hi;
|
|
delay(TXX);
|
|
|
|
return 1;
|
|
}
|
|
|
|
static unsigned char recv_byte(void) {
|
|
int i;
|
|
unsigned char byte=0;
|
|
|
|
for (i=7;i>=0;i--)
|
|
byte |= (recv_bit() << i);
|
|
|
|
return byte;
|
|
}
|
|
|
|
static int recv_ack(void)
|
|
{
|
|
unsigned int ack;
|
|
|
|
ack = (unsigned int)recv_bit();
|
|
scl_lo;
|
|
|
|
if (ack) {
|
|
do_idle();
|
|
printk(KERN_ERR "Error reading the Atmel 24C32/24C64 EEPROM \n");
|
|
return -1;
|
|
}
|
|
|
|
return ack;
|
|
}
|
|
|
|
/*
|
|
* This function does the actual read of the EEPROM. It needs the buffer into which the
|
|
* read data is copied, the size of the EEPROM being read and the buffer size
|
|
*/
|
|
int read_eeprom(char *buffer, int eeprom_size, int size)
|
|
{
|
|
int i = 0, err;
|
|
|
|
send_start();
|
|
send_byte(W_HEADER);
|
|
recv_ack();
|
|
|
|
/* EEPROM with size of more then 2K need two byte addressing */
|
|
if (eeprom_size > 2048) {
|
|
send_byte(0x00);
|
|
recv_ack();
|
|
}
|
|
|
|
send_start();
|
|
send_byte(R_HEADER);
|
|
err = recv_ack();
|
|
if (err == -1)
|
|
return err;
|
|
|
|
for (i = 0; i < size; i++) {
|
|
*buffer++ = recv_byte();
|
|
send_ack();
|
|
}
|
|
|
|
/* Note : We should do some check if the buffer contains correct information */
|
|
|
|
send_stop();
|
|
}
|