vexpress64: fvp: enable OF_CONTROL

The FVP base model is relying on a DT for Linux operation, so there is
no reason we would need to rely on hardcoded information for U-Boot.
Letting U-Boot use a DT will open up the usage of actual peripherals,
beyond the support for semihosting only.

Enable OF_CONTROL in the Kconfig, and use the latest dts files from
Linux. Depending on whether we use the boot-wrapper or TF-A, there is
already a DTB provided or not, respectively.

To cover the boot-wrapper, we add an arm64 Linux kernel header, which
allows the boot-wrapper to treat U-Boot like a Linux kernel. U-Boot will
find the pointer to the DTB in x0, and will use it.

Even though TF-A carries a DT, at the moment this is not made available
to non-secure world, so to not break users, we use the U-Boot provided
DTB copy in that case. For some reason TF-A puts some DT like structure
at the address x0 is pointing at, but that is very small and doesn't
carry any hardware information. Make the code to ignore those small DTBs.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>

arch/arm/Kconfig

@@ -1256,6 +1256,8 @@ config ARCH_VEXPRESS64
 	select DM
 	select DM_SERIAL
 	select PL01X_SERIAL
+	select OF_CONTROL
+	select CLK
 
 config TARGET_TOTAL_COMPUTE
 	bool "Support Total Compute Platform"

arch/arm/dts/Makefile

@@ -1185,6 +1185,7 @@ dtb-$(CONFIG_TARGET_MX53PPD) += imx53-ppd.dtb
 # TODO(Linus Walleij <linus.walleij@linaro.org>): Should us a single vexpress
 # Kconfig option to build all of these. See examples above.
 dtb-$(CONFIG_TARGET_VEXPRESS_CA9X4) += vexpress-v2p-ca9.dtb
+dtb-$(CONFIG_TARGET_VEXPRESS64_BASE_FVP) += fvp-base-revc.dtb
 dtb-$(CONFIG_TARGET_VEXPRESS64_JUNO) += juno-r2.dtb
 
 dtb-$(CONFIG_TARGET_TOTAL_COMPUTE) += total_compute.dtb

board/armltd/vexpress64/Kconfig

@@ -15,13 +15,14 @@ choice
 config TARGET_VEXPRESS64_BASE_FVP
 	bool "Support Versatile Express ARMv8a FVP BASE model"
 	select SEMIHOSTING
+	select LINUX_KERNEL_IMAGE_HEADER
+	select POSITION_INDEPENDENT
+	select OF_BOARD
 
 config TARGET_VEXPRESS64_JUNO
 	bool "Support Versatile Express Juno Development Platform"
 	select DM_ETH
 	select USB
-	select OF_CONTROL
-	select CLK
 	select BLK
 	imply OF_HAS_PRIOR_STAGE
 
@@ -34,4 +35,7 @@ config JUNO_DTB_PART
 	  The ARM partition name in the NOR flash memory holding the
 	  device tree blob to configure U-Boot.
 
+config LNX_KRNL_IMG_TEXT_OFFSET_BASE
+	default SYS_TEXT_BASE
+
 endif

board/armltd/vexpress64/vexpress64.c

@@ -168,11 +168,17 @@ void *board_fdt_blob_setup(int *err)
 	}
 #endif
 
-	if (fdt_magic(prior_stage_fdt_address) == FDT_MAGIC) {
+	if (fdt_magic(prior_stage_fdt_address) == FDT_MAGIC &&
+	    fdt_totalsize(prior_stage_fdt_address) > 0x100) {
 		*err = 0;
 		return (void *)prior_stage_fdt_address;
 	}
 
+	if (fdt_magic(gd->fdt_blob) == FDT_MAGIC) {
+		*err = 0;
+		return (void *)gd->fdt_blob;
+	}
+
 	*err = -ENXIO;
 	return NULL;
 }

configs/vexpress_aemv8a_semi_defconfig

@@ -7,6 +7,7 @@ CONFIG_SYS_MALLOC_F_LEN=0x2000
 CONFIG_NR_DRAM_BANKS=2
 CONFIG_ENV_SIZE=0x40000
 CONFIG_ENV_SECT_SIZE=0x40000
+CONFIG_DEFAULT_DEVICE_TREE="fvp-base-revc"
 CONFIG_IDENT_STRING=" vexpress_aemv8a"
 CONFIG_SYS_MEMTEST_START=0x80000000
 CONFIG_SYS_MEMTEST_END=0xff000000
@@ -46,4 +47,3 @@ CONFIG_FLASH_CFI_DRIVER=y
 CONFIG_SYS_FLASH_USE_BUFFER_WRITE=y
 CONFIG_SYS_FLASH_PROTECTION=y
 CONFIG_SYS_FLASH_CFI=y
-CONFIG_OF_LIBFDT=y