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/* Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#define _GNU_SOURCE /* for asprintf */
#include <errno.h>
#include <fcntl.h>
#include <linux/i2c.h>
#include <linux/i2c-dev.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "comm-host.h"
#define EC_I2C_ADDR 0x1e
#define I2C_ADAPTER_NODE "/sys/class/i2c-adapter/i2c-%d/name"
#define I2C_ADAPTER_NAME "cros_ec_i2c"
#define I2C_MAX_ADAPTER 32
#define I2C_NODE "/dev/i2c-%d"
#ifdef DEBUG
#define debug(format, arg...) printf(format, ##arg)
#else
#define debug(...)
#endif
static int i2c_fd = -1;
int comm_init(void)
{
char *file_path;
char buffer[64];
FILE *f;
int i;
/* find the device number based on the adapter name */
for (i = 0; i < I2C_MAX_ADAPTER; i++) {
if (asprintf(&file_path, I2C_ADAPTER_NODE, i) < 0)
return -1;
f = fopen(file_path, "r");
if (f) {
if (fgets(buffer, sizeof(buffer), f) &&
!strncmp(buffer, I2C_ADAPTER_NAME, 6)) {
free(file_path);
break;
}
fclose(f);
}
free(file_path);
}
if (i == I2C_MAX_ADAPTER) {
fprintf(stderr, "Cannot find I2C adapter\n");
return -1;
}
if (asprintf(&file_path, I2C_NODE, i) < 0)
return -1;
debug("using I2C adapter %s\n", file_path);
i2c_fd = open(file_path, O_RDWR);
if (i2c_fd < 0)
fprintf(stderr, "Cannot open %s : %d\n", file_path, errno);
free(file_path);
return 0;
}
/* Sends a command to the EC. Returns the command status code, or
* -1 if other error. */
int ec_command(int command, const void *indata, int insize,
void *outdata, int outsize)
{
struct i2c_rdwr_ioctl_data data;
int ret = -1;
int i;
uint8_t res_code;
uint8_t *req_buf = NULL;
uint8_t *resp_buf = NULL;
const uint8_t *c;
uint8_t *d;
uint8_t sum;
struct i2c_msg i2c_msg[2];
if (i2c_fd < 0)
return -EC_RES_ERROR;
if (ioctl(i2c_fd, I2C_SLAVE, EC_I2C_ADDR) < 0) {
fprintf(stderr, "Cannot set I2C slave address\n");
return -EC_RES_ERROR;
}
i2c_msg[0].addr = EC_I2C_ADDR;
i2c_msg[0].flags = 0;
i2c_msg[1].addr = EC_I2C_ADDR;
i2c_msg[1].flags = I2C_M_RD;
data.msgs = i2c_msg;
data.nmsgs = 2;
if (outsize) {
/* allocate larger packet
* (one byte for checksum, one for result code)
*/
resp_buf = calloc(1, outsize + 2);
if (!resp_buf)
goto done;
i2c_msg[1].len = outsize + 2;
i2c_msg[1].buf = (char *)resp_buf;
} else {
i2c_msg[1].len = 1;
i2c_msg[1].buf = (char *)&res_code;
}
if (insize) {
/* allocate larger packet
* (one byte for checksum, one for command code)
*/
req_buf = calloc(1, insize + 2);
if (!req_buf)
goto done;
i2c_msg[0].len = insize + 2;
i2c_msg[0].buf = (char *)req_buf;
req_buf[0] = command;
debug("i2c req %02x:", command);
/* copy message payload and compute checksum */
for (i = 0, sum = 0, c = indata; i < insize; i++, c++) {
req_buf[i + 1] = *c;
sum += *c;
debug(" %02x", *c);
}
debug(", sum=%02x\n", sum);
req_buf[insize + 1] = sum;
} else {
i2c_msg[0].len = 1;
i2c_msg[0].buf = (char *)&command; /* nasty cast */
}
/* send command to EC and read answer */
ret = ioctl(i2c_fd, I2C_RDWR, &data);
if (ret < 0) {
fprintf(stderr, "i2c transfer failed: %d (err: %d)\n",
ret, errno);
ret = -EC_RES_ERROR;
goto done;
}
/* check response error code */
ret = i2c_msg[1].buf[0];
if (ret) {
debug("command 0x%02x returned an error %d\n",
command, i2c_msg[1].buf[0]);
/* Translate ERROR to -ERROR */
ret = -ret;
} else if (outsize) {
debug("i2c resp :");
/* copy response packet payload and compute checksum */
for (i = 0, sum = 0, d = outdata; i < outsize; i++, d++) {
*d = resp_buf[i + 1];
sum += *d;
debug(" %02x", *d);
}
debug(", sum=%02x\n", sum);
if (sum != resp_buf[outsize + 1]) {
debug("bad packet checksum\n");
ret = -EC_RES_ERROR;
goto done;
}
/* Return output buffer size */
ret = outsize;
}
done:
if (resp_buf)
free(resp_buf);
if (req_buf)
free(req_buf);
return ret;
}
uint8_t read_mapped_mem8(uint8_t offset)
{
struct ec_params_read_memmap p;
uint8_t val;
p.offset = offset;
p.size = sizeof(val);
if (ec_command(EC_CMD_READ_MEMMAP, &p, sizeof(p),
&val, sizeof(val)) < 0)
return 0xff;
return val;
}
uint16_t read_mapped_mem16(uint8_t offset)
{
struct ec_params_read_memmap p;
uint16_t val;
p.offset = offset;
p.size = sizeof(val);
if (ec_command(EC_CMD_READ_MEMMAP, &p, sizeof(p),
&val, sizeof(val)) < 0)
return 0xffff;
return val;
}
uint32_t read_mapped_mem32(uint8_t offset)
{
struct ec_params_read_memmap p;
uint32_t val;
p.offset = offset;
p.size = sizeof(val);
if (ec_command(EC_CMD_READ_MEMMAP, &p, sizeof(p),
&val, sizeof(val)) < 0)
return 0xffffffff;
return val;
}
int read_mapped_string(uint8_t offset, char *buf)
{
struct ec_params_read_memmap p;
int c;
p.offset = offset;
p.size = EC_MEMMAP_TEXT_MAX;
if (ec_command(EC_CMD_READ_MEMMAP, &p, sizeof(p),
buf, EC_MEMMAP_TEXT_MAX) < 0) {
*buf = 0;
return -1;
}
for (c = 0; c < EC_MEMMAP_TEXT_MAX; c++) {
if (buf[c] == 0)
return c;
}
buf[EC_MEMMAP_TEXT_MAX - 1] = 0;
return EC_MEMMAP_TEXT_MAX - 1;
}
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