// SPDX-License-Identifier: GPL-2.0+

/*

 * Chromium OS cros_ec driver - LPC interface

 *

 * Copyright (c) 2012 The Chromium OS Authors.

 */

/*

 * 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 <dm.h>

#include <command.h>

#include <cros_ec.h>

#include <log.h>

#include <time.h>

#include <asm/io.h>

#ifdef DEBUG_TRACE

#define debug_trace(fmt, b...)  debug(fmt, ##b)

#else

#define debug_trace(fmt, b...)

#endif

/* Timeout waiting for a flash erase command to complete */

static const int CROS_EC_CMD_TIMEOUT_MS = 5000;

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) > CROS_EC_CMD_TIMEOUT_MS) {

      debug("%s: Timeout waiting for CROS_EC sync\n",

            __func__);

      return -1;

    }

  }

  return 0;

}

int cros_ec_lpc_packet(struct udevice *udev, int out_bytes, int in_bytes)

{

  struct cros_ec_dev *dev = dev_get_uclass_priv(udev);

  uint8_t *d;

  int i;

  if (out_bytes > EC_LPC_HOST_PACKET_SIZE)

    return log_msg_ret("Cannot send that many bytes\n", -E2BIG);

  if (in_bytes > EC_LPC_HOST_PACKET_SIZE)

    return log_msg_ret("Cannot receive that many bytes\n", -E2BIG);

  if (wait_for_sync(dev))

    return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT);

  /* Write data */

  for (i = 0, d = (uint8_t *)dev->dout; i < out_bytes; i++, d++)

    outb(*d, EC_LPC_ADDR_HOST_PACKET + i);

  /* Start the command */

  outb(EC_COMMAND_PROTOCOL_3, EC_LPC_ADDR_HOST_CMD);

  if (wait_for_sync(dev))

    return log_msg_ret("Timeout waiting ready\n", -ETIMEDOUT);

  /* Read back args */

  for (i = 0, d = dev->din; i < in_bytes; i++, d++)

    *d = inb(EC_LPC_ADDR_HOST_PACKET + i);

  return in_bytes;

}

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;

}

/* Return the byte of EC switch states */

static int cros_ec_lpc_get_switches(struct udevice *dev)

{

  return inb(EC_LPC_ADDR_MEMMAP + EC_MEMMAP_SWITCHES);

}

/*

 * 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 = {

  .packet = cros_ec_lpc_packet,

  .command = cros_ec_lpc_command,

  .check_version = cros_ec_lpc_check_version,

  .get_switches = cros_ec_lpc_get_switches,

};

static const struct udevice_id cros_ec_ids[] = {

  { .compatible = "google,cros-ec-lpc" },

  { }

};

U_BOOT_DRIVER(google_cros_ec_lpc) = {

  .name   = "google_cros_ec_lpc",

  .id   = UCLASS_CROS_EC,

  .of_match = cros_ec_ids,

  .probe    = cros_ec_probe,

  .ops    = &cros_ec_ops,

};