# Script..: slackwareaarch64-<ver>/source/k/scripts/slim-kmods-initrd
#
# Caller: kernel.SlackBuild and the Installer build system
#         Additions to this script can also be pasted into the stage 1 of the
#         'slkpbs' (pre-boot Shell)  within the Installer and OS InitRD when
#          paring down the module collection.
#
# Purpose: Delete a range of unnecessary sub system drivers from within the
#          Slackware OS InitRD (Operating System Initial RAM Disk) and the
#          Slackware Installer. These are not required to boot the OS nor
#          Installer, and unnecessarily inflate the RAM requirements if not
#          removed.
#
# See also: The modules include list is '../sources/kmod-dirlist'
#           kernel.SlackBuild and the Slackware Installer feed that list
#           into 'tar'. The script you're looking at now slims it down depending
#           on whether the OS InitRD or Slackware Installer is being created
#           at build time.
#
# Note: The aim of this is to focus on the heaviest areas and delete what's
#       verifiably not required.  The Slackware Installers and OS InitRD's
#       are generic environments for all consumers.  If you're after reducing
#       the footprint of your own installation, see:
# https://docs.slackware.com/slackwarearm:inst_sa64_rk3399_rockpro64#reducing_boot_time

# Note about crypto:
# https://github.com/ThomasKaiser/sbc-bench/blob/master/results/ARMv8-Crypto-Extensions.md

#set +o posix
#shopt -s extglob

echo "**** Slimming Initial RAM Disk ****"
pushd lib/modules/*/kernel
   # Wipe all but 'crct10dif-ce*':
   rm -rf arch/arm64/crypto/!(crct10dif-ce*)

   # caam is used on the HoneyComb LX2, and Rockchip on the rk3399
   # Pinebook Pro/RockPro64:
   rm -rf drivers/crypto/!(caam|rockchip)

   rm -rf drivers/{bluetooth,interconnect,mailbox,perf,ptp,soundwire,xen,ufs}
   rm -rf drivers/media/{tuners,dvb-core}
   rm -rf drivers/media/platform/{rcar*,qcom,exynos*,vsp1}

   # Networking:
   # Remove Wireless and other non-essentials:
   rm -rf drivers/net/{wireless,can,ipa}

   rm -rf drivers/input/touchscreen
   rm -rf drivers/power/supply

   # Include only the required GPIO drivers for supported Hardware Models:
   # To fix:
   # Invert this logic, to include only those within the
   # input (the list tar uses - ../sources/kmod-dirlist).
   # Otherwise this is going to get crazy.
   rm -rf drivers/hwmon/!(gpio-fan*|raspberrypi-hwmon*|pwm-fan*|amc6821*)

   # Unused file systems:
   rm -rf fs/{squashfs,udf,ufs,isofs,nilfs2,adfs}
   # We just need NFS for the Installer:
   rm -rf net/!(sunrpc)
   # Sound is not required within the Installer or OS InitRD:
   rm -rf sound

   # We retain the most common USB to Serial adapters which
   # can be used to connect to a tty from within the Slackware Installer:
   rm -rf drivers/usb/serial/!(usbserial*|pl2303*|ftdi_sio*)

   # Required/useful within the Installer, but superfluous within the OS InitRD:
   [ -z "${building_installer}" ] && {
      rm -rf mm # includes 'zsmalloc' required by 'zram' module.
      rm -rf fs/{ntfs*,smb,fuse}
      rm -rf drivers/cdrom
      # The drivers below (at least a select number (but we're not being selective yet))
      # are required within the Installer, but they're absent from the OS InitRD because
      # they're loaded from the OS's /lib/modules when the OS Proper boots.
      rm -rf drivers/thermal
      rm -rf drivers/nvmem
      rm -rf drivers/uio
      # There's no ability to open a tty from within the OS InitRD
      # so we don't need to support any USB to Serial adapters:
      rm -rf drivers/usb/serial
   }
popd
echo "**** Completed: Slimming Initial RAM Disk ****"