#!/bin/bash
# Copyright 2019 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.

. /usr/share/misc/shflags

DEFINE_boolean 'read' "${FLAGS_FALSE}" 'Read instead of write' 'r'
FLAGS_HELP="Usage: ${0} [flags] ec.bin"

# Process commandline flags
FLAGS "${@}" || exit 1
eval set -- "${FLAGS_ARGV}"

if [[ "$#" -eq 0 ]]; then
  echo "Missing filename"
  flags_help
  exit 1
fi

# print out canonical path to differentiate between /usr/local/bin and
# /usr/bin installs
echo "$(readlink -f "$0")"

readonly CROS_EC_SPI_MODALIAS_STR="of:NcrfpTCgoogle,cros-ec-spi"

check_hardware_write_protect_disabled() {
  local hardware_write_protect_state="$(crossystem wpsw_cur)"
  if [[ "${hardware_write_protect_state}" != "0" ]]; then
    echo "Please make sure hardware write protect is disabled."
    echo "See https://www.chromium.org/chromium-os/firmware-porting-guide/firmware-ec-write-protection"
    exit 1
  fi
}

# Get the spiid for the fingerprint sensor based on the modalias
# string: https://crbug.com/955117
get_spiid() {
  for dev in /sys/bus/spi/devices/*; do
    if [[ "$(cat "${dev}/modalias")" == "${CROS_EC_SPI_MODALIAS_STR}" ]]; then
      echo "$(basename "${dev}")"
      exit 0
    fi
  done

  exit 1
}

# Taken verbatim from
# https://chromium.googlesource.com/chromiumos/docs/+/master/lsb-release.md#shell
# This should not be used by anything except get_platform_name.
# See https://crbug.com/98462.
lsbval() {
  local key="$1"
  local lsbfile="${2:-/etc/lsb-release}"

  if ! echo "${key}" | grep -Eq '^[a-zA-Z0-9_]+$'; then
    return 1
  fi

  sed -E -n -e \
    "/^[[:space:]]*${key}[[:space:]]*=/{
      s:^[^=]+=[[:space:]]*::
      s:[[:space:]]+$::
      p
    }" "${lsbfile}"
}

# Get the underlying board (reference design) that we're running on (not the
# FPMCU or sensor).
get_platform_name() {
  # "-l" converts to lowercase
  local -l platform_name="$(cros_config /identity platform-name)"

  # If we don't get any result from cros_config, then we have to possible cases:
  #
  # 1) We're running on a non-unibuild device (the only one with FP is nocturne)
  # 2) We're running on a proto device during bringup and the cros_config
  #    settings haven't yet been setup.
  #
  # In either case we can fall back to /etc/lsb-release. It's not recommended
  # to do this, but we don't have any other options in this case.
  #
  # TODO(https://crbug.com/984629): cros_config should handle reading
  # /etc/lsb-release as backup for us.
  if [[ -z "${platform_name}" ]]; then
    echo "Getting platform name from cros_config failed." \
         "Falling back to /etc/lsb-release." 1>&2
    platform_name="$(lsbval "CHROMEOS_RELEASE_BOARD")"
    if [[ -z "${platform_name}" ]]; then
      exit 1
    fi
  fi

  echo "${platform_name}"
}

check_gpio_chip_exists() {
  local gpiochip="$1"
  if [[ ! -e "/sys/class/gpio/${gpiochip}" ]]; then
    echo "Cannot find GPIO chip: ${gpiochip}"
    exit 1
  fi
}

flash_fp_mcu_stm32() {
  local spidev="${1}"
  local gpio_nrst="${2}"
  local gpio_boot0="${3}"
  local gpio_pwren="${4}"
  local file="${5}"
  local spiid

  local STM32MON_READ_FLAGS=" -U -u -p -s ${spidev} -r"
  local STM32MON_WRITE_FLAGS="-U -u -p -s ${spidev} -e -w"
  local stm32mon_flags=""

  if [[ "${FLAGS_read}" -eq "${FLAGS_TRUE}" ]]; then
    if [[ -e "${file}" ]]; then
      echo "Output file already exists: ${file}"
      exit 1
    fi
    stm32mon_flags="${STM32MON_READ_FLAGS}"
  else
    if [[ ! -f "${file}" ]]; then
      echo "Invalid image file: ${file}"
      exit 1
    fi
    stm32mon_flags="${STM32MON_WRITE_FLAGS}"
  fi

  check_hardware_write_protect_disabled

  spiid="$(get_spiid)"
  if [[ $? -ne 0 ]]; then
    echo "Unable to find FP sensor SPI device: ${CROS_EC_SPI_MODALIAS_STR}"
    exit 1
  fi

  echo "Flashing SPI device ID: ${spiid}"

  # Ensure the ACPI is not cutting power when unloading cros-ec-spi
  if [[ -n "${gpio_pwren}" ]]; then
    echo "${gpio_pwren}" > /sys/class/gpio/export
    echo "out" > "/sys/class/gpio/gpio${gpio_pwren}/direction"
    echo 1 > "/sys/class/gpio/gpio${gpio_pwren}/value"
  fi

  # Remove cros_fp if present
  echo "${spiid}" > /sys/bus/spi/drivers/cros-ec-spi/unbind

  # Configure the MCU Boot0 and NRST GPIOs
  echo "${gpio_boot0}" > /sys/class/gpio/export
  echo "out" > "/sys/class/gpio/gpio${gpio_boot0}/direction"
  echo "${gpio_nrst}" > /sys/class/gpio/export
  echo "out" > "/sys/class/gpio/gpio${gpio_nrst}/direction"

  # Reset sequence to enter bootloader mode
  echo 1 > "/sys/class/gpio/gpio${gpio_boot0}/value"
  echo 0 > "/sys/class/gpio/gpio${gpio_nrst}/value"
  sleep 0.001

  # load spidev (fail on cros-ec-spi first to change modalias)
  echo "${spiid}" > /sys/bus/spi/drivers/cros-ec-spi/bind 2>/dev/null
  echo "${spiid}" > /sys/bus/spi/drivers/spidev/bind

  # Release reset as the SPI bus is now ready
  echo 1 > "/sys/class/gpio/gpio${gpio_nrst}/value"
  echo "in" > "/sys/class/gpio/gpio${gpio_nrst}/direction"

  stm32mon ${stm32mon_flags} "${file}"

  # unload spidev
  echo "${spiid}" > /sys/bus/spi/drivers/spidev/unbind

  # Go back to normal mode
  echo "out" > "/sys/class/gpio/gpio${gpio_nrst}/direction"
  echo 0 > "/sys/class/gpio/gpio${gpio_boot0}/value"
  echo 0 > "/sys/class/gpio/gpio${gpio_nrst}/value"
  echo 1 > "/sys/class/gpio/gpio${gpio_nrst}/value"

  # Give up GPIO control
  echo "in" > "/sys/class/gpio/gpio${gpio_boot0}/direction"
  echo "in" > "/sys/class/gpio/gpio${gpio_nrst}/direction"
  echo "${gpio_boot0}" > /sys/class/gpio/unexport
  echo "${gpio_nrst}" > /sys/class/gpio/unexport

  # wait for FP MCU to come back up (including RWSIG delay)
  sleep 2
  # Put back cros_fp driver
  echo "${spiid}" > /sys/bus/spi/drivers/cros-ec-spi/bind
  # Kernel driver is back, we are no longer controlling power
  if [[ -n "${gpio_pwren}" ]]; then
    echo "${gpio_pwren}" > /sys/class/gpio/unexport
  fi
  # Test it
  ectool --name=cros_fp version
}

config_hatch() {
  check_gpio_chip_exists "gpiochip200"

  readonly SPIDEV="/dev/spidev1.1"
  # FPMCU RST_ODL is on GPP_A12 = 200 + 12 = 212
  readonly GPIO_NRST=212
  # FPMCU BOOT0 is on GPP_A22 = 200 + 22 = 222
  readonly GPIO_BOOT0=222
  # No PWREN GPIO on Hatch, FPMCU is always on
  readonly GPIO_PWREN=""
}

config_nami() {
  check_gpio_chip_exists "gpiochip360"

  readonly SPIDEV="/dev/spidev32765.0"
  # FPMCU RST_ODL is on GPP_C9 = 360 + 57 = 417
  readonly GPIO_NRST=417
  # FPMCU BOOT0 is on GPP_D5 = 360 + 77 = 437
  readonly GPIO_BOOT0=437
  # FP_PWR_EN is on GPP_B11 = 360 + 35 = 395
  readonly GPIO_PWREN=395
}

config_nocturne() {
  check_gpio_chip_exists "gpiochip360"

  readonly SPIDEV="/dev/spidev32765.0"
  # FPMCU RST_ODL is on GPP_C10 = 360 + 58 = 418
  readonly GPIO_NRST=418
  # FPMCU BOOT0 is on GPP_C8 = 360 + 56 = 416
  readonly GPIO_BOOT0=416
  # FP_PWR_EN is on GPP_A11 = 360 + 11 = 371
  readonly GPIO_PWREN=371
}

# The "platform name" corresponds to the underlying board (reference design)
# that we're running on (not the FPMCU or sensor). At the moment all of the
# reference designs use the same GPIOs. If for some reason a design differs in
# the future, we will want to add a nested check in the config_<platform_name>
# function. Doing it in this manner allows us to reduce the number of
# configurations that we have to maintain (and reduces the amount of testing
# if we're only updating a specific config_<platform_name>).
readonly PLATFORM_NAME="$(get_platform_name)"

echo "Using config for ${PLATFORM_NAME}"

# Check that the config function exists
if [[ "$(type -t "config_${PLATFORM_NAME}")" != "function" ]]; then
  echo "No config for platform ${PLATFORM_NAME}"
  exit 1
fi

config_${PLATFORM_NAME}

if [[ $? -ne 0 ]]; then
  echo "Configuration failed for platform ${PLATFORM_NAME}"
  exit 1
fi

flash_fp_mcu_stm32 \
  "${SPIDEV}"      \
  "${GPIO_NRST}"   \
  "${GPIO_BOOT0}"  \
  "${GPIO_PWREN}"  \
  "${1}"