fs/skeleton/bin/watchdog

#!/bin/sh
#
# Program the hardware watchdog counter.
#

onusr1()
{
  quit
}

quit()
{
  $stop
  exit 0
}

trap onusr1 USR1

delay=5

if is-windcharger; then
  timeout=170
  delay=30
  WDIOC_GETBOOTSTATUS=0x40045702
fi

platform=$(cat /etc/platform)

if [ -c /dev/watchdog ]; then
  init=devwatchdog_init
  setup=devwatchdog_setup
  pushback=devwatchdog_pushback
  stop=devwatchdog_stop
  file=/dev/watchdog
elif [ -c /dev/comcerto_wdt ]; then
  init=devwatchdog_init
  setup=devwatchdog_setup
  pushback=devwatchdog_pushback
  stop=devwatchdog_stop
  file=/dev/comcerto_wdt
elif grep -q "BCM7425" /proc/cpuinfo; then
  # GFHD100
  init=bcm7425_init
  setup=bcm_setup
  pushback=bcm_pushback
  stop=
elif grep -q "BCM7429" /proc/cpuinfo; then
  # GFHD200
  init=bcm7429_init
  setup=bcm_setup
  pushback=bcm_pushback
  stop=
elif [ "$platform" = "GFHD254" ]; then
  init=bcm7252_init
  setup=bcm_setup
  pushback=bcm_pushback
else
  echo "Unknown CPU type, cannot initialize watchdog timer"
  cat /proc/cpuinfo
  exit 1
fi

echo -1000 >/proc/$$/oom_score_adj

write()
{
  devmem "$@" >/dev/null
}

#
# /dev/watchdog support
#
# delay can be set when loading module

devwatchdog_init()
{
  wait-until-created $file

  if [ -n "$timeout" ]; then
    WDIOC_SETTIMEOUT=-1073457402    # 0xc0045706
    ioctl -l 4 -- /dev/watchdog $WDIOC_SETTIMEOUT $timeout
  fi

  if [ -n "$WDIOC_GETBOOTSTATUS" ]; then
    if ! ioctl -l 4 -- /dev/watchdog $WDIOC_GETBOOTSTATUS |
	   grep "return buf: 00 00 00 00"; then
      echo "*** Warning *** watchdog reboot detected"
    fi
  fi
}

devwatchdog_setup()
{
  exec 9>$file
}

devwatchdog_pushback()
{
  echo -n X >&9
}

devwatchdog_stop()
{
  echo -n V >&9
}

#
# BCM support
#

# The watch counter.  It counts at a clock rate of 27Mhz,
# so the largest timeout we can program is 159s.  The watchdog timer triggers
# an NMI midway which as at approx. 79.5s.  Our custom NMI handler in the
# kernel dumps the CPU registers and calls panic() i.e. reboots the box. If,
# for some reason, this fails, the watchdog timer will eventually assert a chip
# reset event after another 79.5s.  (The software watchdog is currently at 70s)

bcm7425_init()
{
  timer_wdtimeout_reg=0x104067e8
  timer_wdcmd_reg=0x104067ec
  timer_wdchiprst_cnt_reg=0x104067f0
  timer_wdctrl_reg=0x104067fc
}

bcm7429_init()
{
  timer_wdtimeout_reg=0x104066e8
  timer_wdcmd_reg=0x104066ec
  timer_wdchiprst_cnt_reg=0x104066f0
  timer_wdctrl_reg=0x104066fc
}

bcm7252_init()
{
  timer_wdtimeout_reg=0xf040a7a8
  timer_wdcmd_reg=0xf040a7ac
  timer_wdchiprst_cnt_reg=0xf040a7b0
  timer_wdctrl_reg=0xf040a7bc
}

bcm_setup()
{
  # WD timeout value: 159.072862778 seconds (an NMI is triggered halfway through)
  wdtimeout_val=0xffffffff

  # WD event mode: NMI asserted when WD timer is midway, and chip reset asserted
  # when WD timer expires
  wd_event_mode=0x2

  # WD chip reset length: 2.49 seconds (maximum)
  wdchiprst_cnt_val=0x3ffffff

  # Stop and reprogram the watchdog timer
  write $timer_wdcmd_reg 32 0xee00
  write $timer_wdcmd_reg 32 0x00ee
  write $timer_wdtimeout_reg 32 $wdtimeout_val
  write $timer_wdctrl_reg 32 $wd_event_mode
  write $timer_wdchiprst_cnt_reg 32 $wdchiprst_cnt_val
}

bcm_pushback()
{
  write $timer_wdcmd_reg 32 0xff00
  write $timer_wdcmd_reg 32 0x00ff
}

#
# init, setup, pushback timer
#

$init
$setup

# Start the watchdog timer and reload every n seconds
while true; do
  $pushback
  sleep $delay
done

quit