# Copyright 2025   Stuart Winter, Donostia, Spain
# All rights reserved.
#
# Redistribution and use of this script, with or without modification, is
# permitted provided that the following conditions are met:
#
# 1. Redistributions of this script must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
#
#  THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
#  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
#  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
#  EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
#  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
#  OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
#  WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
#  OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
#  ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#
##########################################################################################
# Program: sair.conf/rpi4
# Purpose: Raspberry Pi 4 helper script for 'SAIR' (Slackware AArch64 Installer Respinner)
#          This script will adjust the Slackware AArch64 Installer image to function with
#          the Raspberry Pi Kernel fork package.
#          This can be used as a reference for other Hardware Models.
# Author : Stuart Winter <mozes@slackware.com>
# Date...: 03-Sept-2025
# Version: 1.00
##########################################################################################

##########################################################################################
# Slackware AiO Installer image layout for RPi #
##########################################################################################
#root@honey:/dev/shm# fdisk -l rpi.img
#Disk rpi.img: 13 GiB, 13958643712 bytes, 27262976 sectors
#Units: sectors of 1 * 512 = 512 bytes
#Sector size (logical/physical): 512 bytes / 512 bytes
#I/O size (minimum/optimal): 512 bytes / 512 bytes
#Disklabel type: dos
#Disk identifier: 0x982553fa
#
#Device     Boot   Start      End  Sectors  Size Id Type
#rpi.img1           2048  4196351  4194304    2G  b W95 FAT32
#rpi.img2   *    4196352  7812499  3616148  1.7G 83 Linux
#rpi.img3        9764864 27262975 17498112  8.3G 83 Linux
#
#rpi.img1 = fat32 partition for the Raspberry Pi's proprietary boot loader
#rpi.img2 = ext4 partition for the Slackware OS /boot directory
#
#rpi.img3 = ext4 partition that contains the Slackware installation media (packages).
#Location of packages: <mount point>/slackware/slackwareaarch64-current/slackware

# The .slktree file should be evaluated to discover the version of Slackware.
#root@honey:/mnt/floppy/slackware# cat .slktree
# slackwareaarch64-current/slackware
#root@honey:/tmp# losetup --partscan --find --show rpi-aio.img
#/dev/loop0
#root@honey:/tmp# blkid /dev/loop0p*
#/dev/loop0p1: LABEL_FATBOOT="SLKhwm_bw" LABEL="SLKhwm_bw" UUID="733E-582F" BLOCK_SIZE="512" TYPE="vfat" PARTUUID="982553fa-01"
#/dev/loop0p2: LABEL="SLKboot" UUID="51943f6f-1617-4393-9272-6e597b51f350" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="982553fa-02"
#/dev/loop0p3: LABEL="SLKins_aio-pkgs" UUID="672a8afd-1027-4dc2-8878-a92599d3d4f9" BLOCK_SIZE="4096" TYPE="ext4" PARTUUID="982553fa-03"
##########################################################################################

# Initialisation function:
function hwm_initialise() {
 pinfo "RPi helper: initialising ..."

 # Sanity check that we have available resources:
 # SLACKWAREVERSION is set within the slackkit config file - e.g. 'slackwareaarch64-current'

 # RPi Kernel fork packages:
 rpi_kernelpkgdir=${rpi_kernelpkgdir:-$HOME/armedslack/experimental/${SLACKWAREVERSION}/rpi-kernel-fork/}
 [ -d "${rpi_kernelpkgdir}" ] && {
    pinfo "RPi Kernel fork directory: ${rpi_kernelpkgdir}" ;} || {
    pinfo "Error: RPi Kernel fork directory is missing" ; return 1 ;}
  # This handler relates to the Raspberry Pi 4. This string is used to match
  # the Slackware package files - e.g. 'kernel_armv8-6.12.44-aarch64-1_rpi4.txz'
  rpi_hwm=rpi4
  kernel_base=kernel_armv?-+([^-])-+([^-])-+([^-])_${rpi_hwm}
  kernel_pkg="$(basename $rpi_kernelpkgdir/${kernel_base}.t?z )"
  pinfo "Kernel package: ${kernel_pkg}"

  # Slackware ARM platform artifacts store:
  [ -d "${SLACKPLATFORMDIR}" ] && {
    pinfo "Slackware ARM platform directory: ${SLACKPLATFORMDIR}" ;} || {
    pinfo "Error: Slackware ARM platform directory is missing" ; return 1 ;}

  # Determine the U-Boot binary we'll be using.
  # The version within the Slackware AArch64 AiO image will be an old build,
  # so we'll replace it with the latest build:
  #
  # RPi5 note: we don't yet build a separate U-Boot for the RPi5. We need to establish
  # whether it's required or whether we can use a generic one as you can with the rpi3&4.
  # If we cannot, we also need to update the a/hwm-bw-raspberrypi package's doinst.sh
  # to both package it, and install the correct version depending on which HWM is in use.
  hwm_soc=bcm2711 
  uboot_bin=$( echo ${SLACKPLATFORMDIR}/bootware/bin/${hwm_soc}/u-boot*/*u-boot.bin )
  [ -f ${uboot_bin} ] && {
     pinfo "U-Boot binary: ${uboot_bin}" ;} || {
     pinfo "Error: Unable to find U-Boot binary for ${rpi_hwm}/${hwm_soc}" ; return 1 ;}

  # Hardware Model Bootware package for the Raspberry Pi:
  # This is generic for all RPi models:
  hwm_bw_pkg=$( echo ${PKGSTORE}/a/hwm-bw-raspberrypi-*.t?z )
  [ -f $hwm_bw_pkg ] && {
     pinfo "Hardware Model Bootware package: ${hwm_bw_pkg}" ;} || {
     pinfo "Error: unable to find Hardware Model Bootware package" ; return 1 ;}
}

# Handlers for the partitions we're working with:

# /boot file system:
function fs_handler_SLKhwm_bw() {
   local fs_loc=$1
   pinfo "RPi helper: Hardware Model Bootware file system ..."

   # RPi proprietary boot loader configuration files:
   # $fs_loc/config.txt
   #   
   # Presently we don't need to adjust the settings within the RPi's proprietary
   # Boot Loader config, but we'll replace the existing one with the latest
   # from the Slackware ARM platform repository:
   pinfo "RPi helper: Updating RPi bootloader config ..."
   install -pm644 ${SLACKPLATFORMDIR}/bootware/src/platform/aarch64/bcm2711/assets/config.txt ${fs_loc}/

   # RPi's proprietary Linux Kernel cmdline settings:
   # $fs_loc/cmdline.txt
   # If you plan on not using U-Boot, you will need to modify this file.
   # When using U-Boot (the standard Slackware approach for the RPis) you should never need to edit this file,
   # and it's shipped empty in Slackware.
   # Slackware uses U-Boot to set these, and are handled within this script's handler function
   # 'fs_handler_SLKboot'.

   # Replace the shipped RPi bootware stuff with the latest versions held within the Slackware package.
   # We'll just overwrite them rather than deleting first.
   pinfo "Updating RPi bootware ..."
   tar -xf ${hwm_bw_pkg} \
       --wildcards \
       --strip-components=4 \
       -C "${fs_loc}" \
       'usr/share/hwm-bw-raspberrypi/bootloader-firmware/*' || return 1
   # This is superfluous and is an excess from the tar above:
   rm -f ${fs_loc}/*u-boot.bin

   # Replace the shipped U-Boot with the latest version from the Slackware ARM
   # "platform" directory.
   pinfo "Updating U-Boot ..."
   install -pm644 ${uboot_bin} ${fs_loc}/slk_u-boot.bin

   # Replace the DTBs with those held within the Slackware RPi Kernel fork package:
   # Only the RPi3 DTBs are shipped within the Slackware Hardware Model Bootware package
   # (see above), so we obtain the rest from the Kernel package.
   # References:
   # RPi Kernel package helper script: /boot/platform/aarch64/helper/pkg-kernel-rpi
   # Source download script: source/a/hwm-bw-raspberrypi/sources/get-firmware.sh
   pinfo "Updating DTBs ..."
   # Unpack the Kernel into temporary space:
   rm -rf $TMPDIR/extract/kernel
   mkdir -p $TMPDIR/extract/kernel
   tar xf ${rpi_kernelpkgdir}/${kernel_pkg} -C $TMPDIR/extract/kernel || return 1
   # Note: the DTBs are duplicated within the SLKhwm_bw partition and the /boot partition.
   # This is because we use the RPi's proprietary boot loader to load DTBs and overlays
   # since there is ample documentation for it, and U-Boot doesn't seem to handle it well
   # on the RPi for some reason.  We maintain them in /boot since that's the Slackware standard,
   # and if you want to use U-Boot to load DTBs, they're ready for use.
   cp -dpRfL $TMPDIR/extract/kernel/boot/dtb*/broadcom/* ${fs_loc}/
   # The reference for the following is here: /boot/platform/aarch64/helper/pkg-kernel-rpi
   # This is maintained within the 'source/k/boot-skeleton/platform/aarch64/helper/pkg-kernel-rpi'
   # Kernel package post install script helper.
   #
   # Update the Kernel with the latest RPi Kernel fork Kernel:
   install -pm755 $TMPDIR/extract/kernel/boot/Image-armv* ${fs_loc}/slk_image-armv8

   ######################################################################################
   # For development purposes, we'll copy the dev versions from a local repository:
   #[ -f ${SAIRDATA}/cmdline.txt ] && install -vpm644 ${SAIRDATA}/cmdline.txt $fs_loc/
   #[ -f ${SAIRDATA}/config.txt ] && install -vpm644 ${SAIRDATA}/config.txt $fs_loc/
   ######################################################################################

}

# /boot/platform/hwm_bw file system:
function fs_handler_SLKboot() {
   local fs_loc=$1
   pinfo "RPi helper: /boot file system ..."

   # Purge the standard Slackware kernel artifacts (kernel, OS initrd, DTBs, Kernel config, System.map)
   # The initrd here is the Slackware Installer, not the OS:
   purge_kernel_artifacts ${fs_loc} || return 1

   # Unpack RPi Kernel fork package and create symlinks from the package's install script:
   # This is a standard setup for the OS and/or Installer.
   setup_kernel_artifacts ${fs_loc} ${rpi_kernelpkgdir}/${kernel_pkg} || return 1

   #### Slackware Installer modifications #################################################
   # Unpack the Slackware Installer that's contained within the Slackware tree.
   # This is the 'bare' installer. The 'purge_kernel_artifacts' function wipes the
   # version within the Slackware Installer sd card image, as there's no reason to ever
   # use an older version of the Slackware Installer.
   unpack_slk_installer ${PORTROOTDIR}/installer/initrd-armv8.img || return 1

   # Replace the official Slackware Kernel package's Kernel modules with those from
   # the RPi Kernel fork package:
   setup_kernel_mods_installer ${rpi_kernelpkgdir}/${kernel_pkg} || return 1

   # Filter the Kernel module list to include the standard set of module categories.
   # This is to load only what's required within the OSInitRD or Installer.
   # Note: For the moment we'll install all of the modules from the RPi Kernel fork
   # package since it's pretty light weight and has an entirely different Kernel
   # configuration.
   #setup_kernel_mods_filter

   # Rebuild Kernel module dependency map:
   setup_kernel_mods_depmod || return 1

   # Set a flag to enable the Slackware Installer to run the Raspberry Pi Kernel Fork
   # helper scripts, which adjust the settings to align with the Kernel fork - e.g.
   # changing the serial console address.
   # The Post setup script within the Installer checks for the presence of this file:
   #  '/usr/share/hwm-configure/platform/aarch64/installer/helper.scr/rpi-kernel-fork-configure'
   touch $TMPDIR/installer-unpacked/.is-rpi-kernel-fork

   # For development purposes, cause the Installer to pause before running
   # the post installation scripts:
   touch $TMPDIR/installer-unpacked/.post-install-pause

   # Repack the modified Installer image and store it within our mounted partition:
   # Note: no symlinks are used here - 'initrd-armv8.img' is the file.
   # Symlinked initrd's are only used for the OS InitRD and do not contain the '.img' extension.
   repack_slk_installer ${fs_loc}/initrd-armv8.img || return 1
   #########################################################################################

   # If you want to boot the Slackware OS using the Raspberry Pi's proprietary boot loader
   # rather than U-Boot, you need to set this option.  This will be picked up by the post
   # install helper script:
   #
   # Note: this installer plugin hasn't been written yet..
   # /usr/share/hwm-configure/platform/aarch64/installer/helper.scr/003-rpip_bl-configure
   # You can also touch a feature flag file within the Installer to achieve the same thing:
   # touch /.rpi_conf_bl_native
   #CONF_RPIP_BL="rpi_conf_bl_native"
   # Default is to boot the OS using U-Boot. This option exists for testing, development
   # & troubleshooting purposes only.
   CONF_RPIP_BL=""

   # Modify the extlinux.conf of the installer image to set the kernel cmdline
   # We add the standard stuff required for the RPi Kernel fork's non-standard settings:
   sed -i '/^[[:blank:]]*APPEND[[:blank:]]/ s/$/ 8250.nr_uarts=1 '"${CONF_RPIP_BL}"' /' \
          ${fs_loc}/extlinux/extlinux.conf
}

# Update/replace various Slackware packages with newer/alternate versions:
function fs_handler_SLKins_aio-pkgs() {
   local fs_loc=$1
   pinfo "RPi helper: AiO Slackware package store file system ..."

   # Determine the version of Slackware we're working with:
   # If this file is missing, the Installer will fail. No reason it shouldn't, but
   # who knows.
   [ ! -f ${fs_loc}/slackware/.slktree ] && {
      echo "ERROR: Cannot determine Slackware version within the AiO file system" ; return 1 ;}

   # Enter the root of the package repository:
   # Example of the pwd now: /tmp/sair/mnt/SLKins_aio-pkgs/slackware
   pushd ${fs_loc}/slackware > /dev/null || return 1

   # Enter the versioned Slackware tree:
   pushd $( <.slktree ) > /dev/null || return 1
   # Example of the pwd now: /tmp/sair/mnt/SLKins_aio-pkgs/slackware/slackwareaarch64-current/slackware

   # Handle the 'a' series:
   pinfo "Handling 'a' series packages ..."
   pushd a > /dev/null

   # Replace standard Slackware kernel package with RPi Kernel fork version:
   # These packages live outside of the regular Slackware tree.
   rm -fv kernel_armv?-+([^-])-+([^-])-+([^-]).{t?z,txt,asc}
   install -pm644 ${rpi_kernelpkgdir}/${kernel_pkg} .
   # Generate .txt file. We could copy the one in the directory where the Kernel package lives
   # (if there is one), but we can easily make a new one using 'slackdtxt' from the 'slacktrack'
   # package:
   slackdtxt ${kernel_pkg}
   # We don't need to make a GPG signature since it's not considered by the Slackware Installer.
   # Users can rely on the GPG signature of the entire installer image.

   # Update standard Slackware kernel-firmware package:
   # The version of the package we're using resides within the regular/official Slackware tree
   # and is simply the latest version (versus the package within the AiO image which will likely
   # be much older)
   rm -f kernel-firmware-*
   install -pm644 ${PKGSTORE}/a/kernel-firmware-*.t* .

   # Update Raspberry Pi Hardware Model package which contains U-Boot and the RPi firmware:
   # Update the a/hwm-bw-raspberrypi-1.20250326-aarch64-1.txz
   rm -f hwm-hwm-bw-raspberrypi-*
   install -pm644 ${PKGSTORE}/a/hwm-bw-raspberrypi-* .

   # Leave package series directory:
   popd > /dev/null

   # Handle the 'k' series:
   pushd k > /dev/null
   rm -f kernel-source*
   install -pm644 ${rpi_kernelpkgdir}/kernel-source-*${rpi_hwm}*.t?z .
   slackdtxt kernel-source-*t?z
   
   # Leave package series directory:
   popd > /dev/null

   # Add any other package updates here.
   # Note that we don't replace the 'd/kernel-headers' package, since that should
   # remain the same version that the 'l/glibc' package was compiled against.

   # Re-enter the root of the repo
   # Example of the pwd now: /tmp/sair/mnt/SLKins_aio-pkgs/slackware
   popd > /dev/null
}

# Finalisation routine:
# Anything final? No use cases at the moment.
#function hwm_finalise() {
#  echo "Finalisation routine"
#}