Add dedicated variables for partition alignment and storage offset

These variables will be used to fill test configuration file.

Issues: MEN-2102

Changelog: None

Signed-off-by: Adam Podogrocki <a.podogrocki@gmail.com>

mender-convert-functions.sh

@@ -1,8 +1,12 @@
 #!/bin/bash
 
-# Erase block size 8MiB
-erase_block=8388608
+# Partition alignment value in bytes (8MB).
+partition_alignment=8388608
+# Boot partition storage offset in bytes (8MB).
+vfat_storage_offset=8388608
+# Number of required heads in a final image.
 heads=255
+# Number of required sectors in a final image.
 sectors=63
 
 declare -a sdimg_partitions=("boot" "primary" "secondary" "data")
@@ -220,7 +224,7 @@ get_sdimg_info() {
 
 # Takes following arguments:
 #
-#  $1 - size variable to be aligned
+#  $1 - size variable to be aligned in sectors
 #  $2 - size of the sector
 #
 align_partition_size() {
@@ -229,10 +233,10 @@ align_partition_size() {
   local -n ref=$1
 
   local size_in_bytes=$(( $ref * $2 ))
-  local reminder=$(( ${size_in_bytes} % ${erase_block} ))
+  local reminder=$(( ${size_in_bytes} % ${partition_alignment} ))
 
   if [ $reminder -ne 0 ]; then
-    size_in_bytes=$(( $size_in_bytes - $reminder + ${erase_block} ))
+    size_in_bytes=$(( $size_in_bytes - $reminder + ${partition_alignment} ))
   fi
 
   local lsize=$(( $size_in_bytes / $2 ))
@@ -277,11 +281,14 @@ analyse_embedded_image() {
     echo -e "\nDetected single partition embedded image."
     rootfssize=$bootsize
     # Default size of the boot partition: 16MiB.
-    bootsize=$(( ($erase_block * 2) / $sectorsize ))
+    bootsize=$(( ($partition_alignment * 2) / $sectorsize ))
   elif [[ $count -eq 2 ]]; then
     echo -e "\nDetected multipartition ($count) embedded image."
   fi
 
+  # Boot partition storage offset is defined from the top down.
+  bootstart=$(( $vfat_storage_offset / $sectorsize ))
+
   align_partition_size bootsize $sectorsize
   align_partition_size rootfssize  $sectorsize
 

mender-convert.sh

@@ -107,8 +107,8 @@ tool_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 sector_size=
 # Boot partition start in sectors (512 bytes per sector).
 pboot_start=
-# Default 'boot' partition size in sectors: 16MiB
-# (i.e 16777216 bytes, equals to 'erase_block' * 2)
+# Default 'boot' partition size in sectors: 16MB
+# (i.e 16777216 bytes, equals to 'partition_alignment' * 2)
 pboot_size=
 # Default 'data' partition size in MiB.
 data_size=128