------------Write value 0 instead of 1 for testing purpose-------------------
        power_reset(0)
        retry_count += 1
        print(retry_count)
    io_reg_write(PORT_RES, RESET_REG, COLD_RESET)
~
~
"platform_reboot" 63L, 1757C written
root@sonic:/usr/share/sonic/device/x86_64-dell_s6000_s1220-r0# ./platform_reboot
1
2


BIOS (Dell Inc) Boot Selector
S6000-ACS 3.10.0.1 (32-port TE/FG)


POST Configuration
  CPU Signature 30669
  CPU FamilyID=6, Model=36, SteppingId=9, Processor=0
  Microcode Revision 10b
  POST Control=0xea000303, Status=0xe6009f00
MSRs:
  Platform ID: f098859045
  PMG_CST_CFG_CTL: 263006
  BBL_CR_CTL3: 7e00010f
  Perf Ctrl & status: 63d, 63d104506000648
  P-Unit reg55h: 0x48810000

  Perf cnt (curr/fixed): 268ac2e0/66c768c0
  Clk Flex Max: 0
  Misc EN: 60840080
  Therm Status: 88420000 (offset=0x0)
  MC0 Ctl: 0
  MC0 Status: 0

  Booting `SONiC-OS-20181130.85'

Loading SONiC-OS OS kernel ...
Loading SONiC-OS OS initial ramdisk ...
[    2.600889] BERT: Can't request iomem region <00000000bfa2ac18-00000000bfa2ac2b>.
[    4.474188] pstore: decompression failed;returned -5
[    6.214303] kvm: disabled by bios
[    6.357253] kvm: disabled by bios
[    6.507147] rc.local[493]: + sonic-cfggen -y /etc/sonic/sonic_version.yml -v build_version
[   11.121918] rc.local[493]: + SONIC_VERSION=20181130.85
[   11.193523] rc.local[493]: + FIRST_BOOT_FILE=/host/image-20181130.85/platform/firsttime
[   11.305661] rc.local[493]: + logger SONiC version 20181130.85 starting up...
[   11.406499] rc.local[493]: + grub_installation_needed=
[   11.477599] rc.local[493]: + [ ! -e /host/machine.conf ]
[   11.549709] rc.local[493]: + migrate_nos_configuration
[   11.617315] rc.local[493]: + rm -rf /host/migration
[   11.677549] rc.local[493]: + mkdir -p /host/migration
[   11.743060] rc.local[493]: + cat /proc/cmdline
[   11.806674] rc.local[493]: + set -- BOOT_IMAGE=/image-20181130.85/boot/vmlinuz-4.9.0-9-amd64 root=UUID=75c8b96d-26d7-4b1b-beb8-6cf03998feea rw console=tty0 console=ttyS0,9600n8 quiet net.ifnames=0 biosdevname=0 loop=image-20181130.85/fs.squashfs loopfstype=squashfs apparmor=1 security=apparmor varlog_size=4096 usbcore.autosuspend=-1 processor.max_cstate=1 intel_idle.max_cstate=0 crashkernel=0M-2G:256M,2G-4G:320M,4G-8G:384M,8G-:448M
[   12.276762] rc.local[493]: + [ -n  ]
[   12.320787] rc.local[493]: + . /host/machine.conf
[   12.381428] rc.local[493]: + onie_version=3.20.1.B-8
[   12.452850] rc.local[493]: + onie_vendor_id=674
[   12.512862] rc.local[493]: + onie_platform=x86_64-dell_s6000_s1220-r0
[   12.600874] rc.local[493]: + onie_machine=dell_s6000_s1220
[   12.672852] rc.local[493]: + onie_machine_rev=0
[   12.732814] rc.local[493]: + onie_arch=x86_64
[   12.792764] rc.local[493]: + onie_config_version=1
[   12.852701] rc.local[493]: + onie_build_date=2019-04-02T12:05-07:00
[   12.928771] rc.local[493]: + onie_partition_type=gpt
[   13.004670] rc.local[493]: + onie_kernel_version=4.1.28                                                                                           [0/1823]
[   13.076673] rc.local[493]: + onie_firmware=auto
[   13.140757] rc.local[493]: + onie_switch_asic=bcm
[   13.204663] rc.local[493]: + onie_skip_ethmgmt_macs=no
[   13.276900] rc.local[493]: + [ x = xx86_64-arista_7060_cx32s ]
[   13.353835] rc.local[493]: + [ x = xx86_64-arista_7050_qx32s ]
[   13.428626] rc.local[493]: + program_console_speed
[   13.508944] rc.local[493]: + cat /proc/cmdline
[   13.569816] rc.local[493]: + grep -Eo console=ttyS[0-9]+,[0-9]+
[   13.645918] rc.local[493]: + cut -d , -f2
[   13.702748] rc.local[493]: + speed=9600
[   13.756696] rc.local[493]: + [ -z 9600 ]
[   13.812965] rc.local[493]: + CONSOLE_SPEED=9600
[   13.872702] rc.local[493]: + sed -i s|\-\-keep\-baud .* %I| 9600 %I|g /lib/systemd/system/serial-getty@.service
[   14.005012] rc.local[493]: + systemctl daemon-reload
[   14.077036] rc.local[493]: + [ -f /host/image-20181130.85/platform/firsttime ]
[   14.168878] rc.local[493]: + exit 0

Debian GNU/Linux 9 sonic ttyS0

sonic login: