/*
* tc_i2c.c
* --------
* This module contains common code to talk to the FPGA over the I2C bus.
*
* Author: Paul Selkirk
* Copyright (c) 2014-2015, NORDUnet A/S All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of the NORDUnet nor the names of its contributors may
* be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "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 COPYRIGHT
* HOLDER OR CONTRIBUTORS 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.
*/
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include <linux/i2c-dev.h>
#include <sys/ioctl.h>
#include <stdint.h>
#include "tc_i2c.h"
extern int debug;
/* ---------------- I2C low-level code ---------------- */
static int i2cfd;
static void dump(char *label, const uint8_t *buf, size_t len)
{
if (debug) {
int i;
printf("%s [", label);
for (i = 0; i < len; ++i)
printf(" %02x", buf[i]);
printf(" ]\n");
}
}
static void i2c_close(void)
{
close(i2cfd);
}
int i2c_open(char *dev, int addr)
{
i2cfd = open(dev, O_RDWR);
if (i2cfd < 0) {
fprintf(stderr, "Unable to open %s: ", dev);
perror("");
i2cfd = 0;
return 1;
}
if (ioctl(i2cfd, I2C_SLAVE, addr) < 0) {
fprintf(stderr, "Unable to set I2C slave device 0x%02x: ", addr);
perror("");
return 1;
}
if (atexit(i2c_close) != 0) {
fprintf(stderr, "Unable to set I2C atexit handler.");
return 1;
}
return 0;
}
static int i2c_write(const uint8_t *buf, size_t len)
{
dump("write ", buf, len);
if (write(i2cfd, buf, len) != len) {
perror("i2c write failed");
return 1;
}
return 0;
}
static int i2c_read(uint8_t *b)
{
/* read() on the i2c device only returns one byte at a time,
* and tc_get_resp() needs to parse the response one byte at a time
*/
if (read(i2cfd, b, 1) != 1) {
perror("i2c read failed");
return 1;
}
return 0;
}
/* ---------------- test-case low-level code ---------------- */
/* coretest command codes */
#define SOC 0x55
#define EOC 0xaa
#define READ_CMD 0x10
#define WRITE_CMD 0x11
#define RESET_CMD 0x01
/* coretest response codes */
#define SOR 0xaa
#define EOR 0x55
#define READ_OK 0x7f
#define WRITE_OK 0x7e
#define RESET_OK 0x7d
#define UNKNOWN 0xfe
#define ERROR 0xfd
static int tc_send_write_cmd(off_t offset, const uint8_t *data)
{
uint8_t buf[9] = { SOC, WRITE_CMD, (offset >> 8) & 0xff, offset & 0xff,
data[0], data[1], data[2], data[3], EOC };
return i2c_write(buf, sizeof(buf));
}
static int tc_send_read_cmd(off_t offset)
{
uint8_t buf[5] = { SOC, READ_CMD, (offset >> 8) & 0xff, offset & 0xff, EOC };
return i2c_write(buf, sizeof(buf));
}
static int tc_get_resp(uint8_t *buf, size_t len)
{
int i;
for (i = 0; i < len; ++i) {
if (i2c_read(&buf[i]) != 0)
return 1;
if ((i == 0) && (buf[i] != SOR)) {
/* we've gotten out of sync, and there's probably nothing we can do */
fprintf(stderr, "response byte 0: expected 0x%02x (SOR), got 0x%02x\n",
SOR, buf[0]);
return 1;
}
else if (i == 1) { /* response code */
switch (buf[i]) {
case READ_OK:
len = 9;
break;
case WRITE_OK:
len = 5;
break;
case RESET_OK:
len = 3;
break;
case ERROR:
case UNKNOWN:
len = 4;
break;
default:
/* we've gotten out of sync, and there's probably nothing we can do */
fprintf(stderr, "unknown response code 0x%02x\n", buf[i]);
return 1;
}
}
}
dump("read ", buf, len);
return 0;
}
static int tc_compare(uint8_t *buf, const uint8_t *expected, size_t len)
{
int i;
/* start at byte 1 because SOR has already been tested */
for (i = 1; i < len; ++i) {
if (buf[i] != expected[i]) {
fprintf(stderr, "response byte %d: expected 0x%02x, got 0x%02x\n",
i, expected[i], buf[i]);
return 1;
}
}
return 0;
}
static int tc_get_write_resp(off_t offset)
{
uint8_t buf[5];
uint8_t expected[5] = { SOR, WRITE_OK, (offset >> 8) & 0xff, offset & 0xff, EOR };
return
tc_get_resp(buf, sizeof(buf)) ||
tc_compare(buf, expected, sizeof(expected));
}
static int tc_get_read_resp(off_t offset, uint8_t *data)
{
uint8_t buf[9];
uint8_t expected[4] = { SOR, READ_OK, (offset >> 8) & 0xff, offset & 0xff };
if ((tc_get_resp(buf, sizeof(buf)) != 0) ||
(tc_compare(buf, expected, 4) != 0) || buf[8] != EOR)
return 1;
data[0] = buf[4];
data[1] = buf[5];
data[2] = buf[6];
data[3] = buf[7];
return 0;
}
static int tc_get_read_resp_expected(off_t offset, const uint8_t *data)
{
uint8_t buf[9];
uint8_t expected[9] = { SOR, READ_OK, (offset >> 8) & 0xff, offset & 0xff,
data[0], data[1], data[2], data[3], EOR };
dump("expect", expected, 9);
return (tc_get_resp(buf, sizeof(buf)) ||
tc_compare(buf, expected, sizeof(buf)));
}
int tc_write(off_t offset, const uint8_t *buf, size_t len)
{
for (; len > 0; offset++, buf += 4, len -= 4) {
if (tc_send_write_cmd(offset, buf) ||
tc_get_write_resp(offset))
return 1;
}
return 0;
}
int tc_read(off_t offset, uint8_t *buf, size_t len)
{
for (; len > 0; offset++, buf += 4, len -= 4) {
if (tc_send_read_cmd(offset) ||
tc_get_read_resp(offset, buf))
return 1;
}
return 0;
}
int tc_expected(off_t offset, const uint8_t *buf, size_t len)
{
for (; len > 0; offset++, buf += 4, len -= 4) {
if (tc_send_read_cmd(offset) ||
tc_get_read_resp_expected(offset, buf))
return 1;
}
return 0;
}
int tc_wait(off_t offset, uint8_t status, int *count)
{
uint8_t buf[4];
int i;
for (i = 1; ; ++i) {
if (count && (*count > 0) && (i >= *count)) {
fprintf(stderr, "tc_wait timed out\n");
return 1;
}
if (tc_read(offset, buf, 4) != 0)
return -1;
if (buf[3] & status) {
if (count)
*count = i;
return 0;
}
}
}
