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