#################################################################################
# Helper script: /load_kernel_modules.scr/platform/aarch64/bcm2837
# Purpose......: Set the Kernel modules for Hardware Models that use the BCM2837
#                SoC within the Slackware initial RAM disk ('OS initrd')
#                and the Slackware installer.
#                Currently supported Hardware Models:
#                * Raspberry Pi 3
#                This script is sourced from '/load_kernel_modules'
# Author.......: Stuart Winter <mozes@slackware.com>
# Date.........: 30-Mar-2021
# Maintainer...: 
#
# Please use this as a reference and example of how to add support for
# a new SoC to Slackware ARM/AArch64.
#
# Important Note:
# * You must _append_ to the module lists (include the variable
#   name within the variable itself), otherwise the base
#   set of modules will not be loaded and would result in
#   a Kernel panic.
# * The initrd uses the 'bash' shell, rather than 'busybox'
#   (as in upstream/x86 Slackware). This allows you (for example)
#   to use 'fallthrough' (case statements terminated with ';&'
#   rather than ';;') within case statements and regular expression
#   matches within 'if' statements.
#   This permits the 'c'-style switch statements where you can
#   'inherit' the previous matches as you move down the cases.
#   This enables you to match on varients of boards, and inherit
#   a 'baseline' of platform modules for that board.
#
# The 'PLATWALK' match is to enable build scripts to process these
# scripts outside of the initrd environment and determine which
# modules will be loaded by a particular Hardware Model.  This must remain
# in place for all scripts.
#################################################################################

case $HWM in
   "Raspberry Pi 3"*|PLATWALK)
      platform_detected=1
      SOC_NAME=bcm2837
      # Set the short name that is used by /load_kernel_modules to install
      # the appropriate configuration for modprobe for this Hardware Model:
      HWM_SHORTNAME=rpi3
      echo "Architecture: ${ARCH}, Hardware model: ${HWM}, SoC: ${SOC_NAME}"
      # If one of the modules within the base list is causing problems on
      # your platform, here are the options laid out as examples:
      # USB="${USB/ehci_orion/differentmodule}" # Substitute module 'ehci_orion' with 'differentmodule'
      # USB="${USB/ehci_orion/}" # Remove the 'ehci_orion' module from the list
      MOD_GPIO+="   "
      MOD_PHY+="    bcm_phy_lib phy_generic"
      MOD_VIDEO+="  simpledrm"
      MOD_CARDS+="  sdhci-iproc bcm2835"
      MOD_USB+="    dwc2"
      MOD_NET+="    "
      MOD_CMP+="    "
      MOD_CRYPTO+=" "
      # Example to detect hardware at runtime:
      #{ lspci 2>/dev/null | grep -q 'SATA cont.*ATA' ;} && MOD_XX="$MOD_XX yyy"
      # The following modules do not inherit:
      MOD_RTC="rtc-ds1307 rtc-pcf8523" 
      # Modules for the peripherals on the Hardware Model's main board
      # (outside of the SoC itself)
      MOD_HWM=""
      # Modules for the IP blocks/peripherals embedded within the SoC:
      MOD_SOC=""
      ;;

      # Note: The RPi3 will probably benefit from the same post-module-loading
      # function as included within the RPi4's helper script, which initialises
      # an RTC on the GPIO array.
      # The RPi3 support is presently only supported to the basic level though,
      # and this can enhancement can be added later when there are people
      # with hardware and interest to test it.
esac

# The '/load_kernel_modules' script will load the modules
# set above.