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/* Copyright (c) 2013 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.
*/
#include <stdint.h>
#include <stdio.h>
#include <sys/io.h>
#include <sys/param.h>
#include <unistd.h>
#include "comm-host.h"
#define INITIAL_UDELAY 5 /* 5 us */
#define MAXIMUM_UDELAY 10000 /* 10 ms */
/*
* Wait for the EC to be unbusy. Returns 0 if unbusy, non-zero if
* timeout.
*/
static int wait_for_ec(int status_addr, int timeout_usec)
{
int i;
int delay = INITIAL_UDELAY;
for (i = 0; i < timeout_usec; i += delay) {
/*
* Delay first, in case we just sent out a command but the EC
* hasn't raise the busy flag. However, I think this doesn't
* happen since the LPC commands are executed in order and the
* busy flag is set by hardware.
*
* TODO: move this delay after inb(status).
*/
usleep(MIN(delay, timeout_usec - i));
if (!(inb(status_addr) & EC_LPC_STATUS_BUSY_MASK))
return 0;
/* Increase the delay interval after a few rapid checks */
if (i > 20)
delay = MIN(delay * 2, MAXIMUM_UDELAY);
}
return -1; /* Timeout */
}
static int ec_command_lpc(int command, int version,
const void *outdata, int outsize,
void *indata, int insize)
{
struct ec_lpc_host_args args;
const uint8_t *d;
uint8_t *dout;
int csum;
int i;
/* Fill in args */
args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
args.command_version = version;
args.data_size = outsize;
/* Initialize checksum */
csum = command + args.flags + args.command_version + args.data_size;
/* Write data and update checksum */
for (i = 0, d = (uint8_t *)outdata; i < outsize; i++, d++) {
outb(*d, EC_LPC_ADDR_HOST_PARAM + i);
csum += *d;
}
/* Finalize checksum and write args */
args.checksum = (uint8_t)csum;
for (i = 0, d = (const uint8_t *)&args; i < sizeof(args); i++, d++)
outb(*d, EC_LPC_ADDR_HOST_ARGS + i);
outb(command, EC_LPC_ADDR_HOST_CMD);
if (wait_for_ec(EC_LPC_ADDR_HOST_CMD, 1000000)) {
fprintf(stderr, "Timeout waiting for EC response\n");
return -EC_RES_ERROR;
}
/* Check result */
i = inb(EC_LPC_ADDR_HOST_DATA);
if (i) {
fprintf(stderr, "EC returned error result code %d\n", i);
return -i;
}
/* Read back args */
for (i = 0, dout = (uint8_t *)&args; i < sizeof(args); i++, dout++)
*dout = inb(EC_LPC_ADDR_HOST_ARGS + i);
/*
* If EC didn't modify args flags, then somehow we sent a new-style
* command to an old EC, which means it would have read its params
* from the wrong place.
*/
if (!(args.flags & EC_HOST_ARGS_FLAG_TO_HOST)) {
fprintf(stderr, "EC protocol mismatch\n");
return -EC_RES_INVALID_RESPONSE;
}
if (args.data_size > insize) {
fprintf(stderr, "EC returned too much data\n");
return -EC_RES_INVALID_RESPONSE;
}
/* Start calculating response checksum */
csum = command + args.flags + args.command_version + args.data_size;
/* Read response and update checksum */
for (i = 0, dout = (uint8_t *)indata; i < args.data_size;
i++, dout++) {
*dout = inb(EC_LPC_ADDR_HOST_PARAM + i);
csum += *dout;
}
/* Verify checksum */
if (args.checksum != (uint8_t)csum) {
fprintf(stderr, "EC response has invalid checksum\n");
return -EC_RES_INVALID_CHECKSUM;
}
/* Return actual amount of data received */
return args.data_size;
}
static int ec_readmem_lpc(int offset, int bytes, void *dest)
{
int i = offset;
char *s = dest;
int cnt = 0;
if (offset >= EC_MEMMAP_SIZE - bytes)
return -1;
if (bytes) { /* fixed length */
for (; cnt < bytes; i++, s++, cnt++)
*s = inb(EC_LPC_ADDR_MEMMAP + i);
} else { /* string */
for (; i < EC_MEMMAP_SIZE; i++, s++) {
*s = inb(EC_LPC_ADDR_MEMMAP + i);
cnt++;
if (!*s)
break;
}
}
return cnt;
}
int comm_init_lpc(void)
{
int i;
int byte = 0xff;
/* Request I/O privilege */
if (iopl(3) < 0) {
perror("Error getting I/O privilege");
return -3;
}
/*
* Test if the I/O port has been configured for Chromium EC LPC
* interface. If all the bytes are 0xff, very likely that Chromium EC
* is not present.
*
* TODO: (crosbug.com/p/10963) Should only need to look at the command
* byte, since we don't support ACPI burst mode and thus bit 4 should
* be 0.
*/
byte &= inb(EC_LPC_ADDR_HOST_CMD);
byte &= inb(EC_LPC_ADDR_HOST_DATA);
for (i = 0; i < EC_HOST_PARAM_SIZE && byte == 0xff; ++i)
byte &= inb(EC_LPC_ADDR_HOST_PARAM + i);
if (byte == 0xff) {
fprintf(stderr, "Port 0x%x,0x%x,0x%x-0x%x are all 0xFF.\n",
EC_LPC_ADDR_HOST_CMD, EC_LPC_ADDR_HOST_DATA,
EC_LPC_ADDR_HOST_PARAM,
EC_LPC_ADDR_HOST_PARAM + EC_HOST_PARAM_SIZE - 1);
fprintf(stderr,
"Very likely this board doesn't have a Chromium EC.\n");
return -4;
}
/*
* Test if LPC command args are supported.
*
* The cheapest way to do this is by looking for the memory-mapped
* flag. This is faster than sending a new-style 'hello' command and
* seeing whether the EC sets the EC_HOST_ARGS_FLAG_FROM_HOST flag
* in args when it responds.
*/
if (inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID) != 'E' ||
inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_ID + 1) != 'C' ||
!(inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_HOST_CMD_FLAGS) &
EC_HOST_CMD_FLAG_LPC_ARGS_SUPPORTED)) {
fprintf(stderr, "EC doesn't support command args.\n");
return -5;
}
/* Okay, this works */
ec_command = ec_command_lpc;
ec_readmem = ec_readmem_lpc;
return 0;
}
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