grub.cfg: use grub_scan_disk to set boot order

Previously, grub_scan_disk could set ata, ahci or "both",
which would make both be tried (ahci first). This worked
when we only dealt with ata and ahci devices, but now we
support nvme devices so the logic is inherently flawed.

Instead, use grub_scan_disk to store the boot order, e.g.:

grub_scan_disk="ahci nvme ata"

grub_scan_disk="nvme ata"

In the first example, it would make GRUB scan ahci first,
then nvme and then ata.

In the secontd example, it would make GRUB scan nvme first,
and then ata.

If "both" is set, or anything other than ahci/ata/nvme,
grub_scan_disk is now changed to "nvme ahci ata".

Actual grub_scan_disk entries in target.cfg files will now
be modified, to match each machine.

Signed-off-by: Leah Rowe <leah@libreboot.org>

config/grub/config/grub.cfg

@@ -50,7 +50,7 @@ if [ -f (cbfsdisk)/timeout.cfg ]; then
 else	
 	set timeout=5
 fi
-set grub_scan_disk="both"
+set grub_scan_disk="nvme ahci ata"
 if [ -f (cbfsdisk)/scan.cfg ]; then
 	source (cbfsdisk)/scan.cfg
 fi
@@ -139,15 +139,9 @@ function search_bootcfg {
 }
 menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o' {
 
-	if [ "${grub_scan_disk}" != "ata" ]; then
+	for grub_disk in ${grub_scan_disk}; do
-		search_bootcfg ahci
+		search_bootcfg ${grub_disk}
-	fi
+	done
-	if [ "${grub_scan_disk}" != "ahci" ]; then
-		search_bootcfg ata
-	fi
-	if [ "${grub_scan_disk}" != "nvme" ]; then
-		search_bootcfg nvme
-	fi
 
 	# grub device enumeration is very slow, so checks are hardcoded
 
@@ -169,22 +163,22 @@ menuentry 'Load Operating System (incl. fully encrypted disks)  [o]' --hotkey='o
 	unset nvmedev
 	for i in 11 10 9 8 7 6 5 4 3 2 1 0; do
 		for part in 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1; do
-			if [ "${grub_scan_disk}" != "ata" ]; then
+			for grub_disk in ${grub_scan_disk}; do
-				ahcidev="(ahci${i},${part}) ${ahcidev}"
+				if [ "${grub_disk}" = "ahci" ]; then
-			fi
+					ahcidev="(ahci${i},${part}) ${ahcidev}"
-			if [ "${grub_scan_disk}" != "ahci" ]; then
+				elif [ "${grub_disk}" = "ata" ]; then
-				atadev="(ata${i},${part}) ${atadev}"
+					atadev="(ata${i},${part}) ${atadev}"
-			fi
+				elif [ "${grub_disk}" = "nvme" ]; then
-			if [ "${grub_scan_disk}" != "nvme" ]; then
+					# TODO: do we care about other namesapces
-				# TODO: do we care about other namesapces
+					nvmedev="(nvme${i}n1,${part}) ${nvmedev}"
-				nvmedev="(nvme${i}n1,${part}) ${nvmedev}"
+				fi
-			fi
+			done
 		done
 	done
 
 	set pager=0
 	echo -n "Attempting to unlock encrypted volumes"
-	for dev in ${ahcidev} ${atadev} ${nvmedev} ${lvmvol} ${raidvol}; do
+	for dev in ${nvmedev} ${ahcidev} ${atadev} ${lvmvol} ${raidvol}; do
 		if cryptomount "${dev}" ; then break ; fi
 	done
 	set pager=1

script/roms

@@ -150,9 +150,21 @@ configure_target()
 	# Override the above defaults using target.cfg
 	. "$targetdir/target.cfg"
 
-	[ -z "$grub_scan_disk" ] && grub_scan_disk="both"
+	[ -z "$grub_scan_disk" ] && grub_scan_disk="nvme ahci ata"
-	[ "$grub_scan_disk" != "both" ] && [ "$grub_scan_disk" != "ata" ] && \
+	_ata=""
-	    [ "$grub_scan_disk" != "ahci" ] && grub_scan_disk="both"
+	_ahci=""
+	_nvme=""
+	_grub_scan_disk=""
+	for _disk in $grub_scan_disk; do
+		[ "$_disk" != "nvme" ] && [ "$_disk" != "ahci" ] && \
+		    [ "$_disk" != "ata" ] && _grub_scan_disk="nvme ahci ata" \
+		    && break
+		eval "[ -n \"\$_$_disk\" ] && continue"
+		eval "_$_disk=\"$_disk\""
+		_grub_scan_disk="$_grub_scan_disk $_disk"
+	done
+	[ -z "$_grub_scan_disk" ] && _grub_scan_disk="nvme ahci ata"
+	grub_scan_disk="${_grub_scan_disk# }"
 
 	[ -z "$tree" ] && $err "$board: tree not defined"
 
@@ -333,8 +345,7 @@ build_grub_roms()
 	tmpcfg="$(mktemp -t coreboot_rom.XXXXXXXXXX)"
 	printf "set grub_scan_disk=\"%s\"\n" "$grub_scan_disk" > "$tmpcfg" || \
 	    $err "set grub_scandisk, $grub_scan_disk, $tmpcfg"
-	[ "$grub_scan_disk" = "both" ] || \
+	x_ "$cbfstool" "$tmprom" add -f "$tmpcfg" -n scan.cfg -t raw
-	    x_ "$cbfstool" "$tmprom" add -f "$tmpcfg" -n scan.cfg -t raw
 	printf "set timeout=%s\n" "$grub_timeout" > "$tmpcfg" || \
 	    $err "set timeout, $grub_timeout, $tmpcfg"
 	[ -z "$grub_timeout" ] || x_ "$cbfstool" "$tmprom" add \