2 files changed, 91 insertions, 0 deletions
diff --git a/src/arch/arm/Makefile.inc b/src/arch/arm/Makefile.inc
index eef2650685..241bfe5051 100644
--- a/src/arch/arm/Makefile.inc
+++ b/src/arch/arm/Makefile.inc
@@ -119,6 +119,7 @@ ramstage-y += memset.S
 ramstage-y += memcpy.S
 ramstage-y += memmove.S
 ramstage-y += clock.c
+ramstage-$(CONFIG_PAYLOAD_FIT_SUPPORT) += fit_payload.c
 
 rmodules_arm-y += memset.S
 rmodules_arm-y += memcpy.S
diff --git a/src/arch/arm/fit_payload.c b/src/arch/arm/fit_payload.c
new file mode 100644
index 0000000000..f5470071d4
--- /dev/null
+++ b/src/arch/arm/fit_payload.c
@@ -0,0 +1,90 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <console/console.h>
+#include <bootmem.h>
+#include <program_loading.h>
+#include <fit.h>
+#include <symbols.h>
+
+/**
+ * Place the region in free memory range.
+ */
+static bool fit_place_mem(const struct range_entry *r, void *arg)
+{
+	struct region *region = arg;
+	resource_t start;
+
+	if (range_entry_tag(r) != BM_MEM_RAM)
+		return true;
+
+	/* Linux 4.15 doesn't like 4KiB alignment. Align to 1 MiB for now. */
+	start = ALIGN_UP(MAX(region->offset, range_entry_base(r)), 1 * MiB);
+
+	if (start + region->size < range_entry_end(r)) {
+		region->offset = (size_t)start;
+		return false;
+	}
+
+	return true;
+}
+
+
+bool fit_payload_arch(struct prog *payload, struct fit_config_node *config,
+		      struct region *kernel,
+		      struct region *fdt,
+		      struct region *initrd)
+{
+	void *arg = NULL;
+
+	/**
+	 * The kernel ARM documentation recommends loading the kernel above 32MiB
+	 * in order to avoid the need to need to relocate prior to decompression.
+	 */
+	kernel->offset = (uintptr_t)_dram + 32 * MiB;
+
+	/**
+	 * The code assumes that bootmem_walk provides a sorted list of memory
+	 * regions, starting from the lowest address.
+	 * The order of the calls here doesn't matter, as the placement is
+	 * enforced in the called functions.
+	 * For details check code on top.
+	 */
+	if (!bootmem_walk(fit_place_mem, kernel))
+		return false;
+
+	/* Mark as reserved for future allocations. */
+	bootmem_add_range(kernel->offset, kernel->size, BM_MEM_PAYLOAD);
+
+	/**
+	 * To ensure the fdt is not overwritten by the kernel decompressor, place
+	 * the fdt above the 128 MB from the start of RAM, as recommended by the
+	 * kernel documentation.
+	 */
+	fdt->offset = (uintptr_t)_dram + 128 * MiB;
+
+	if (!bootmem_walk(fit_place_mem, fdt))
+		return false;
+
+	/* Mark as reserved for future allocations. */
+	bootmem_add_range(fdt->offset, fdt->size, BM_MEM_PAYLOAD);
+
+	/* Place INITRD */
+	if (config->ramdisk) {
+		initrd->offset = fdt->offset + fdt->size;
+
+		if (!bootmem_walk(fit_place_mem, initrd))
+			return false;
+
+		/* Mark as reserved for future allocations. */
+		bootmem_add_range(initrd->offset, initrd->size, BM_MEM_PAYLOAD);
+	}
+
+	/* Kernel expects FDT as argument */
+	arg = (void *)fdt->offset;
+
+	prog_set_entry(payload, (void *)kernel->offset, arg);
+
+	bootmem_dump_ranges();
+
+	return true;
+}