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/*
* Chromium OS cros_ec driver - LPC interface
*
* Copyright (c) 2012 The Chromium OS Authors.
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* The Matrix Keyboard Protocol driver handles talking to the keyboard
* controller chip. Mostly this is for keyboard functions, but some other
* things have slipped in, so we provide generic services to talk to the
* KBC.
*/
#include <common.h>
#include <dm.h>
#include <command.h>
#include <cros_ec.h>
#include <asm/io.h>
#ifdef DEBUG_TRACE
#define debug_trace(fmt, b...) debug(fmt, ##b)
#else
#define debug_trace(fmt, b...)
#endif
static int wait_for_sync(struct cros_ec_dev *dev)
{
unsigned long start;
start = get_timer(0);
while (inb(EC_LPC_ADDR_HOST_CMD) & EC_LPC_STATUS_BUSY_MASK) {
if (get_timer(start) > 1000) {
debug("%s: Timeout waiting for CROS_EC sync\n",
__func__);
return -1;
}
}
return 0;
}
int cros_ec_lpc_command(struct udevice *udev, uint8_t cmd, int cmd_version,
const uint8_t *dout, int dout_len,
uint8_t **dinp, int din_len)
{
struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
const int cmd_addr = EC_LPC_ADDR_HOST_CMD;
const int data_addr = EC_LPC_ADDR_HOST_DATA;
const int args_addr = EC_LPC_ADDR_HOST_ARGS;
const int param_addr = EC_LPC_ADDR_HOST_PARAM;
struct ec_lpc_host_args args;
uint8_t *d;
int csum;
int i;
if (dout_len > EC_PROTO2_MAX_PARAM_SIZE) {
debug("%s: Cannot send %d bytes\n", __func__, dout_len);
return -1;
}
/* Fill in args */
args.flags = EC_HOST_ARGS_FLAG_FROM_HOST;
args.command_version = cmd_version;
args.data_size = dout_len;
/* Calculate checksum */
csum = cmd + args.flags + args.command_version + args.data_size;
for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++)
csum += *d;
args.checksum = (uint8_t)csum;
if (wait_for_sync(dev)) {
debug("%s: Timeout waiting ready\n", __func__);
return -1;
}
/* Write args */
for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
outb(*d, args_addr + i);
/* Write data, if any */
debug_trace("cmd: %02x, ver: %02x", cmd, cmd_version);
for (i = 0, d = (uint8_t *)dout; i < dout_len; i++, d++) {
outb(*d, param_addr + i);
debug_trace("%02x ", *d);
}
outb(cmd, cmd_addr);
debug_trace("\n");
if (wait_for_sync(dev)) {
debug("%s: Timeout waiting for response\n", __func__);
return -1;
}
/* Check result */
i = inb(data_addr);
if (i) {
debug("%s: CROS_EC result code %d\n", __func__, i);
return -i;
}
/* Read back args */
for (i = 0, d = (uint8_t *)&args; i < sizeof(args); i++, d++)
*d = inb(args_addr + 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)) {
debug("%s: CROS_EC protocol mismatch\n", __func__);
return -EC_RES_INVALID_RESPONSE;
}
if (args.data_size > din_len) {
debug("%s: CROS_EC returned too much data %d > %d\n",
__func__, args.data_size, din_len);
return -EC_RES_INVALID_RESPONSE;
}
/* Read data, if any */
for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++) {
*d = inb(param_addr + i);
debug_trace("%02x ", *d);
}
debug_trace("\n");
/* Verify checksum */
csum = cmd + args.flags + args.command_version + args.data_size;
for (i = 0, d = (uint8_t *)dev->din; i < args.data_size; i++, d++)
csum += *d;
if (args.checksum != (uint8_t)csum) {
debug("%s: CROS_EC response has invalid checksum\n", __func__);
return -EC_RES_INVALID_CHECKSUM;
}
*dinp = dev->din;
/* Return actual amount of data received */
return args.data_size;
}
/**
* Initialize LPC protocol.
*
* @param dev CROS_EC device
* @param blob Device tree blob
* @return 0 if ok, -1 on error
*/
int cros_ec_lpc_init(struct cros_ec_dev *dev, const void *blob)
{
int byte, i;
/* See if we can find an EC at the other end */
byte = 0xff;
byte &= inb(EC_LPC_ADDR_HOST_CMD);
byte &= inb(EC_LPC_ADDR_HOST_DATA);
for (i = 0; i < EC_PROTO2_MAX_PARAM_SIZE && (byte == 0xff); i++)
byte &= inb(EC_LPC_ADDR_HOST_PARAM + i);
if (byte == 0xff) {
debug("%s: CROS_EC device not found on LPC bus\n",
__func__);
return -1;
}
return 0;
}
/*
* 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.
*/
static int cros_ec_lpc_check_version(struct udevice *dev)
{
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)) {
return 0;
}
printf("%s: ERROR: old EC interface not supported\n", __func__);
return -1;
}
static int cros_ec_probe(struct udevice *dev)
{
return cros_ec_register(dev);
}
static struct dm_cros_ec_ops cros_ec_ops = {
.command = cros_ec_lpc_command,
.check_version = cros_ec_lpc_check_version,
};
static const struct udevice_id cros_ec_ids[] = {
{ .compatible = "google,cros-ec-lpc" },
{ }
};
U_BOOT_DRIVER(cros_ec_lpc) = {
.name = "cros_ec_lpc",
.id = UCLASS_CROS_EC,
.of_match = cros_ec_ids,
.probe = cros_ec_probe,
.ops = &cros_ec_ops,
};
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