Support for HiFive Unmatched (#386)

This PR adds board support for HiFive Unmatched. (#384)
You can generate SD card image for unmatched using buildroot by single
`make` command.
It will not be available for production, but it will allow for easy
testing.

I checked that almost all example runs correctly, but only `attestor.ke`
throw runtime error bacause the package does not include firmware image
(`fw_jump.elf`) correctly. Same thing is happening with qemu target.

## New items/Changes
- Add buildroot config for unmatched in `overlays/keystone/configs`
- Add board specific configs/patches in `overlays/keystone/board`
- Some patches in `freedom-u-sdk` & `meta-sifive` (2023.08) are included
- Implement secureboot same as bootrom in u-boot. This is applied via a
patch.
- Unmatched's platform overrides in upstream OpenSBI is added to
`sm/plat`
- Add make target to flush SD card image
- Other minor modifications

## Known issue
Porting issue mentioned
[here](https://groups.google.com/g/keystone-enclave-forum/c/6vnr6pWPZjw/m/HBeq4a5OBAAJ)
is still remaining.
With default `SMM_SIZE` (`0x200000`), machine hangs when switching to
S-Mode entering u-boot proper (when function `sbi_hart_switch_mode` is
called).

In this PR, change `SMM_SIZE` to `0x80000` same as sbi domain region by
passing compile flag for unmatched target. This is temporary fix.

## Remarks
FU740 has waymasks same as FU540. Waymasking implemented for FU540 can
be ported to FU740, I think.

.gitignore

@@ -1,7 +1,7 @@
 *~
 *.swp
 .venv/
-build/
+build*/
 riscv/
 riscv64/
 riscv32/

Makefile

@@ -29,6 +29,8 @@ include mkutils/log.mk
 BUILDROOT_CONFIGFILE    ?= qemu_riscv$(KEYSTONE_BITS)_virt_defconfig
 ifeq ($(KEYSTONE_PLATFORM),mpfs)
 	EXTERNALS += microchip
+else ifeq ($(KEYSTONE_PLATFORM),unmatched)
+    BUILDROOT_CONFIGFILE = riscv64_hifive_unmatched_defconfig
 endif
 
 # Highest priority external
@@ -114,3 +116,4 @@ linux-configure: $(BUILDROOT_BUILDDIR)/.config
 #################
 
 -include mkutils/plat/$(KEYSTONE_PLATFORM)/run.mk
+

mkutils/plat/unmatched/run.mk

@@ -0,0 +1,25 @@
+#########################
+## Flush SD card image ##
+#########################
+
+DEVICE      ?=
+EXTEND      ?= 0
+FLUSH_IMAGE ?= $(BUILDROOT_BUILDDIR)/images/sdcard.img
+
+flush:
+ifeq ($(DEVICE),)
+	$(call log,error,Set target device to env DEVICE)
+else
+	$(call log,info,Flushing SD image)
+	sudo dd if=$(FLUSH_IMAGE) of=$(DEVICE) bs=64k iflag=fullblock oflag=direct conv=fsync status=progress
+
+ifeq ($(EXTEND),1)
+	$(call log,info,Extending rootfs end of the block device)
+	echo "w" | sudo fdisk $(DEVICE)
+	echo "- +" | sudo sfdisk -N 3 $(DEVICE)
+	sudo e2fsck -f $(DEVICE)3
+	sudo resize2fs $(DEVICE)3
+endif
+
+endif
+

overlays/keystone/board/sifive/hifive-unmatched/extlinux.conf

@@ -0,0 +1,5 @@
+default buildroot
+label buildroot
+   kernel /boot/Image.gz
+   fdt /boot/hifive-unmatched-a00.dtb
+   append root=/dev/mmcblk0p3 rootfstype=ext4 rootwait console=ttySIF0,115200 earlycon

overlays/keystone/board/sifive/hifive-unmatched/genimage_sdcard.cfg

@@ -0,0 +1,23 @@
+image sdcard.img {
+	hdimage {
+		partition-table-type = "gpt"
+	}
+
+	partition u-boot-spl {
+		image = "u-boot-spl.bin"
+		offset = 17K
+		partition-type-uuid = 5b193300-fc78-40cd-8002-e86c45580b47
+	}
+
+	partition u-boot {
+		image = "u-boot.itb"
+		offset = 1041K
+		partition-type-uuid = 2e54b353-1271-4842-806f-e436d6af6985
+	}
+
+	partition rootfs {
+		image = "rootfs.ext4"
+		partition-type-uuid = 0fc63daf-8483-4772-8e79-3d69d8477de4
+		bootable = true
+	}
+}