upl: Add support for reading a upl handoff

Universal Payload provides a standard way of handing off control between
two firmware phases. Add support for reading the handoff information into
a structure.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index ddcb712..04a6f23 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1709,6 +1709,13 @@
 S:	Maintained
 F:	drivers/ufs/
 
+UPL
+M:	Simon Glass <sjg@chromium.org>
+S:	Maintained
+T:	git https://source.denx.de/u-boot/custodians/u-boot-dm.git
+F:	boot/upl*
+F:	include/upl.h
+
 USB
 M:	Marek Vasut <marex@denx.de>
 S:	Maintained
diff --git a/boot/Kconfig b/boot/Kconfig
index 940389d..3010629 100644
--- a/boot/Kconfig
+++ b/boot/Kconfig
@@ -745,6 +745,25 @@
 	  This provides a way to try out standard boot on an existing boot flow.
 	  It is not enabled by default to save space.
 
+config UPL
+	bool "upl - Universal Payload Specification"
+	imply UPL_READ
+	help
+	  Provides support for UPL payloads and handoff information. U-Boot
+	  supports generating and accepting handoff information. The mkimage
+	  tool will eventually support creating payloads.
+
+if UPL
+
+config UPL_READ
+	bool "upl - Support reading a Universal Payload handoff"
+	help
+	  Provides support for decoding a UPL-format payload into a C structure
+	  which can be used elsewhere in U-Boot. This is just the reading
+	  implementation, useful for trying it out.
+
+endif  # UPL
+
 endif # BOOTSTD
 
 config LEGACY_IMAGE_FORMAT
diff --git a/boot/Makefile b/boot/Makefile
index dff6f99..9e4e5a6 100644
--- a/boot/Makefile
+++ b/boot/Makefile
@@ -43,6 +43,9 @@
 obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += fdt_support.o
 obj-$(CONFIG_$(SPL_TPL_)FDT_SIMPLEFB) += fdt_simplefb.o
 
+obj-$(CONFIG_$(SPL_TPL_)UPL) += upl_common.o
+obj-$(CONFIG_$(SPL_TPL_)UPL_READ) += upl_read.o
+
 obj-$(CONFIG_$(SPL_TPL_)OF_LIBFDT) += image-fdt.o
 obj-$(CONFIG_$(SPL_TPL_)FIT_SIGNATURE) += fdt_region.o
 obj-$(CONFIG_$(SPL_TPL_)FIT) += image-fit.o
diff --git a/boot/upl_common.c b/boot/upl_common.c
new file mode 100644
index 0000000..3924423
--- /dev/null
+++ b/boot/upl_common.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * UPL handoff command functions
+ *
+ * Copyright 2024 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEGORY UCLASS_BOOTSTD
+
+#include <string.h>
+#include <upl.h>
+
+/* Names of bootmodes */
+const char *const bootmode_names[UPLBM_COUNT] = {
+	[UPLBM_FULL]	= "full",
+	[UPLBM_MINIMAL]	= "minimal",
+	[UPLBM_FAST]	= "fast",
+	[UPLBM_DIAG]	= "diag",
+	[UPLBM_DEFAULT]	= "default",
+	[UPLBM_S2]	= "s2",
+	[UPLBM_S3]	= "s3",
+	[UPLBM_S4]	= "s4",
+	[UPLBM_S5]	= "s5",
+	[UPLBM_FACTORY]	= "factory",
+	[UPLBM_FLASH]	= "flash",
+	[UPLBM_RECOVERY] = "recovery",
+};
+
+/* Names of memory usages */
+const char *const usage_names[UPLUS_COUNT] = {
+	[UPLUS_ACPI_RECLAIM]	= "acpi-reclaim",
+	[UPLUS_ACPI_NVS]	= "acpi-nvs",
+	[UPLUS_BOOT_CODE]	= "boot-code",
+	[UPLUS_BOOT_DATA]	= "boot-data",
+	[UPLUS_RUNTIME_CODE]	= "runtime-code",
+	[UPLUS_RUNTIME_DATA]	= "runtime-data",
+};
+
+/* Names of access types */
+const char *const access_types[UPLUS_COUNT] = {
+	[UPLAT_MMIO]	= "mmio",
+	[UPLAT_IO]	= "io",
+};
+
+/* Names of graphics formats */
+const char *const graphics_formats[UPLUS_COUNT] = {
+	[UPLGF_ARGB32]	= "a8r8g8b8",
+	[UPLGF_ABGR32]	= "a8b8g8r8",
+	[UPLGF_ABGR64]	= "a16b16g16r16",
+};
+
+void upl_init(struct upl *upl)
+{
+	memset(upl, '\0', sizeof(struct upl));
+	alist_init_struct(&upl->image, struct upl_image);
+	alist_init_struct(&upl->mem, struct upl_mem);
+	alist_init_struct(&upl->memmap, struct upl_memmap);
+	alist_init_struct(&upl->memres, struct upl_memres);
+}
diff --git a/boot/upl_common.h b/boot/upl_common.h
new file mode 100644
index 0000000..cc517dc
--- /dev/null
+++ b/boot/upl_common.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * UPL handoff command functions
+ *
+ * Copyright 2024 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __UPL_COMMON_H
+#define __UPL_COMMON_H
+
+/* Names of bootmodes */
+extern const char *const bootmode_names[UPLBM_COUNT];
+
+/* Names of memory usages */
+extern const char *const usage_names[UPLUS_COUNT];
+
+/* Names of access types */
+extern const char *const access_types[UPLUS_COUNT];
+
+/* Names of graphics formats */
+extern const char *const graphics_formats[UPLUS_COUNT];
+
+#endif /* __UPL_COMMON_H */
diff --git a/boot/upl_read.c b/boot/upl_read.c
new file mode 100644
index 0000000..5063897
--- /dev/null
+++ b/boot/upl_read.c
@@ -0,0 +1,588 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * UPL handoff parsing
+ *
+ * Copyright 2024 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#define LOG_CATEGORY UCLASS_BOOTSTD
+
+#include <log.h>
+#include <upl.h>
+#include <dm/ofnode.h>
+#include "upl_common.h"
+
+/**
+ * read_addr() - Read an address
+ *
+ * Reads an address in the correct format, either 32- or 64-bit
+ *
+ * @upl: UPL state
+ * @node: Node to read from
+ * @prop: Property name to read
+ * @addr: Place to put the address
+ * Return: 0 if OK, -ve on error
+ */
+static int read_addr(const struct upl *upl, ofnode node, const char *prop,
+		     ulong *addrp)
+{
+	int ret;
+
+	if (upl->addr_cells == 1) {
+		u32 val;
+
+		ret = ofnode_read_u32(node, prop, &val);
+		if (!ret)
+			*addrp = val;
+	} else {
+		u64 val;
+
+		ret = ofnode_read_u64(node, prop, &val);
+		if (!ret)
+			*addrp = val;
+	}
+
+	return ret;
+}
+
+/**
+ * read_size() - Read a size
+ *
+ * Reads a size in the correct format, either 32- or 64-bit
+ *
+ * @upl: UPL state
+ * @node: Node to read from
+ * @prop: Property name to read
+ * @addr: Place to put the size
+ * Return: 0 if OK, -ve on error
+ */
+static int read_size(const struct upl *upl, ofnode node, const char *prop,
+		     ulong *sizep)
+{
+	int ret;
+
+	if (upl->size_cells == 1) {
+		u32 val;
+
+		ret = ofnode_read_u32(node, prop, &val);
+		if (!ret)
+			*sizep = val;
+	} else {
+		u64 val;
+
+		ret = ofnode_read_u64(node, prop, &val);
+		if (!ret)
+			*sizep = val;
+	}
+
+	return ret;
+}
+
+/**
+ * ofnode_read_bitmask() - Read a bit mask from a string list
+ *
+ * @node: Node to read from
+ * @prop: Property name to read
+ * @names: Array of names for each bit
+ * @count: Number of array entries
+ * @value: Returns resulting bit-mask value on success
+ * Return: 0 if OK, -EINVAL if a bit number is not defined, -ENOSPC if the
+ * string is too long for the (internal) buffer, -EINVAL if no such property
+ */
+static int ofnode_read_bitmask(ofnode node, const char *prop,
+			       const char *const names[], uint count,
+			       uint *valuep)
+{
+	const char **list;
+	const char **strp;
+	uint val;
+	uint bit;
+	int ret;
+
+	ret = ofnode_read_string_list(node, prop, &list);
+	if (ret < 0)
+		return log_msg_ret("rea", ret);
+
+	val = 0;
+	for (strp = list; *strp; strp++) {
+		const char *str = *strp;
+		bool found = false;
+
+		for (bit = 0; bit < count; bit++) {
+			if (!strcmp(str, names[bit])) {
+				found = true;
+				break;
+			}
+		}
+		if (found)
+			val |= BIT(bit);
+		else
+			log_warning("%s/%s: Invalid value '%s'\n",
+				    ofnode_get_name(node), prop, str);
+	}
+	*valuep = val;
+
+	return 0;
+}
+
+/**
+ * ofnode_read_value() - Read a string value as an int using a lookup
+ *
+ * @node: Node to read from
+ * @prop: Property name to read
+ * @names: Array of names for each int value
+ * @count: Number of array entries
+ * @valuep: Returns int value read
+ * Return: 0 if OK, -EINVAL if a bit number is not defined, -ENOENT if the
+ * property does not exist
+ */
+static int ofnode_read_value(ofnode node, const char *prop,
+			     const char *const names[], uint count,
+			     uint *valuep)
+{
+	const char *str;
+	int i;
+
+	str = ofnode_read_string(node, prop);
+	if (!str)
+		return log_msg_ret("rd", -ENOENT);
+
+	for (i = 0; i < count; i++) {
+		if (!strcmp(names[i], str)) {
+			*valuep = i;
+			return 0;
+		}
+	}
+
+	log_debug("Unnamed value '%s'\n", str);
+	return log_msg_ret("val", -EINVAL);
+}
+
+static int read_uint(ofnode node, const char *prop, uint *valp)
+{
+	u32 val;
+	int ret;
+
+	ret = ofnode_read_u32(node, prop, &val);
+	if (ret)
+		return ret;
+	*valp = val;
+
+	return 0;
+}
+
+/**
+ * decode_root_props() - Decode root properties from the tree
+ *
+ * @upl: UPL state
+ * @node: Node to decode
+ * Return 0 if OK, -ve on error
+ */
+static int decode_root_props(struct upl *upl, ofnode node)
+{
+	int ret;
+
+	ret = read_uint(node, UPLP_ADDRESS_CELLS, &upl->addr_cells);
+	if (!ret)
+		ret = read_uint(node, UPLP_SIZE_CELLS, &upl->size_cells);
+	if (ret)
+		return log_msg_ret("cel", ret);
+
+	return 0;
+}
+
+/**
+ * decode_root_props() - Decode UPL parameters from the tree
+ *
+ * @upl: UPL state
+ * @node: Node to decode
+ * Return 0 if OK, -ve on error
+ */
+static int decode_upl_params(struct upl *upl, ofnode options)
+{
+	ofnode node;
+	int ret;
+
+	node = ofnode_find_subnode(options, UPLN_UPL_PARAMS);
+	if (!ofnode_valid(node))
+		return log_msg_ret("par", -EINVAL);
+	log_debug("decoding '%s'\n", ofnode_get_name(node));
+
+	ret = read_addr(upl, node, UPLP_SMBIOS, &upl->smbios);
+	if (ret)
+		return log_msg_ret("smb", ret);
+	ret = read_addr(upl, node, UPLP_ACPI, &upl->acpi);
+	if (ret)
+		return log_msg_ret("acp", ret);
+	ret = ofnode_read_bitmask(node, UPLP_BOOTMODE, bootmode_names,
+				  UPLBM_COUNT, &upl->bootmode);
+	if (ret)
+		return log_msg_ret("boo", ret);
+	ret = read_uint(node, UPLP_ADDR_WIDTH, &upl->addr_width);
+	if (ret)
+		return log_msg_ret("add", ret);
+	ret = read_uint(node, UPLP_ACPI_NVS_SIZE, &upl->acpi_nvs_size);
+	if (ret)
+		return log_msg_ret("nvs", ret);
+
+	return 0;
+}
+
+/**
+ * decode_upl_images() - Decode /options/upl-image nodes
+ *
+ * @node: /options node in which to look for the node
+ * Return 0 if OK, -ve on error
+ */
+static int decode_upl_images(struct upl *upl, ofnode options)
+{
+	ofnode node, images;
+	int ret;
+
+	images = ofnode_find_subnode(options, UPLN_UPL_IMAGE);
+	if (!ofnode_valid(images))
+		return log_msg_ret("img", -EINVAL);
+	log_debug("decoding '%s'\n", ofnode_get_name(images));
+
+	ret = read_addr(upl, images, UPLP_FIT, &upl->fit);
+	if (!ret)
+		ret = read_uint(images, UPLP_CONF_OFFSET, &upl->conf_offset);
+	if (ret)
+		return log_msg_ret("cnf", ret);
+
+	ofnode_for_each_subnode(node, images) {
+		struct upl_image img;
+
+		ret = read_addr(upl, node, UPLP_LOAD, &img.load);
+		if (!ret)
+			ret = read_size(upl, node, UPLP_SIZE, &img.size);
+		if (!ret)
+			ret = read_uint(node, UPLP_OFFSET, &img.offset);
+		img.description = ofnode_read_string(node, UPLP_DESCRIPTION);
+		if (!img.description)
+			return log_msg_ret("sim", ret);
+		if (!alist_add(&upl->image, img))
+			return log_msg_ret("img", -ENOMEM);
+	}
+
+	return 0;
+}
+
+/**
+ * decode_addr_size() - Decide a set of addr/size pairs
+ *
+ * Each base/size value from the devicetree is written to the region list
+ *
+ * @upl: UPL state
+ * @buf: Bytes to decode
+ * @size: Number of bytes to decode
+ * @regions: List of regions to process (struct memregion)
+ * Returns: number of regions found, if OK, else -ve on error
+ */
+static int decode_addr_size(const struct upl *upl, const char *buf, int size,
+			    struct alist *regions)
+{
+	const char *ptr, *end = buf + size;
+	int i;
+
+	alist_init_struct(regions, struct memregion);
+	ptr = buf;
+	for (i = 0; ptr < end; i++) {
+		struct memregion reg;
+
+		if (upl->addr_cells == 1)
+			reg.base = fdt32_to_cpu(*(u32 *)ptr);
+		else
+			reg.base = fdt64_to_cpu(*(u64 *)ptr);
+		ptr += upl->addr_cells * sizeof(u32);
+
+		if (upl->size_cells == 1)
+			reg.size = fdt32_to_cpu(*(u32 *)ptr);
+		else
+			reg.size = fdt64_to_cpu(*(u64 *)ptr);
+		ptr += upl->size_cells * sizeof(u32);
+		if (ptr > end)
+			return -ENOSPC;
+
+		if (!alist_add(regions, reg))
+			return log_msg_ret("reg", -ENOMEM);
+	}
+
+	return i;
+}
+
+/**
+ * node_matches_at() - Check if a node name matches "base@..."
+ *
+ * Return: true if the node name matches the base string followed by an @ sign;
+ * false otherwise
+ */
+static bool node_matches_at(ofnode node, const char *base)
+{
+	const char *name = ofnode_get_name(node);
+	int len = strlen(base);
+
+	return !strncmp(base, name, len) && name[len] == '@';
+}
+
+/**
+ * decode_upl_memory_node() - Decode a /memory node from the tree
+ *
+ * @upl: UPL state
+ * @node: Node to decode
+ * Return 0 if OK, -ve on error
+ */
+static int decode_upl_memory_node(struct upl *upl, ofnode node)
+{
+	struct upl_mem mem;
+	const char *buf;
+	int size, len;
+
+	buf = ofnode_read_prop(node, UPLP_REG, &size);
+	if (!buf) {
+		log_warning("Node '%s': Missing '%s' property\n",
+			    ofnode_get_name(node), UPLP_REG);
+		return log_msg_ret("reg", -EINVAL);
+	}
+	len = decode_addr_size(upl, buf, size, &mem.region);
+	if (len < 0)
+		return log_msg_ret("buf", len);
+	mem.hotpluggable = ofnode_read_bool(node, UPLP_HOTPLUGGABLE);
+	if (!alist_add(&upl->mem, mem))
+		return log_msg_ret("mem", -ENOMEM);
+
+	return 0;
+}
+
+/**
+ * decode_upl_memmap() - Decode memory-map nodes from the tree
+ *
+ * @upl: UPL state
+ * @root: Parent node containing the /memory-map nodes
+ * Return 0 if OK, -ve on error
+ */
+static int decode_upl_memmap(struct upl *upl, ofnode root)
+{
+	ofnode node;
+
+	ofnode_for_each_subnode(node, root) {
+		struct upl_memmap memmap;
+		int size, len, ret;
+		const char *buf;
+
+		memmap.name = ofnode_get_name(node);
+		memmap.usage = 0;
+
+		buf = ofnode_read_prop(node, UPLP_REG, &size);
+		if (!buf) {
+			log_warning("Node '%s': Missing '%s' property\n",
+				    ofnode_get_name(node), UPLP_REG);
+			continue;
+		}
+
+		len = decode_addr_size(upl, buf, size, &memmap.region);
+		if (len < 0)
+			return log_msg_ret("buf", len);
+		ret = ofnode_read_bitmask(node, UPLP_USAGE, usage_names,
+					  UPLUS_COUNT, &memmap.usage);
+		if (ret && ret != -EINVAL)	/* optional property */
+			return log_msg_ret("bit", ret);
+
+		if (!alist_add(&upl->memmap, memmap))
+			return log_msg_ret("mmp", -ENOMEM);
+	}
+
+	return 0;
+}
+
+/**
+ * decode_upl_memres() - Decode reserved-memory nodes from the tree
+ *
+ * @upl: UPL state
+ * @root: Parent node containing the reserved-memory nodes
+ * Return 0 if OK, -ve on error
+ */
+static int decode_upl_memres(struct upl *upl, ofnode root)
+{
+	ofnode node;
+
+	ofnode_for_each_subnode(node, root) {
+		struct upl_memres memres;
+		const char *buf;
+		int size, len;
+
+		log_debug("decoding '%s'\n", ofnode_get_name(node));
+		memres.name = ofnode_get_name(node);
+
+		buf = ofnode_read_prop(node, UPLP_REG, &size);
+		if (!buf) {
+			log_warning("Node '%s': Missing 'reg' property\n",
+				    ofnode_get_name(node));
+			continue;
+		}
+
+		len = decode_addr_size(upl, buf, size, &memres.region);
+		if (len < 0)
+			return log_msg_ret("buf", len);
+		memres.no_map = ofnode_read_bool(node, UPLP_NO_MAP);
+
+		if (!alist_add(&upl->memres, memres))
+			return log_msg_ret("mre", -ENOMEM);
+	}
+
+	return 0;
+}
+
+/**
+ * decode_upl_serial() - Decode the serial node
+ *
+ * @upl: UPL state
+ * @root: Parent node contain node
+ * Return 0 if OK, -ve on error
+ */
+static int decode_upl_serial(struct upl *upl, ofnode node)
+{
+	struct upl_serial *ser = &upl->serial;
+	const char *buf;
+	int len, size;
+	int ret;
+
+	ser->compatible = ofnode_read_string(node, UPLP_COMPATIBLE);
+	if (!ser->compatible) {
+		log_warning("Node '%s': Missing compatible string\n",
+			    ofnode_get_name(node));
+		return log_msg_ret("com", -EINVAL);
+	}
+	ret = read_uint(node, UPLP_CLOCK_FREQUENCY, &ser->clock_frequency);
+	if (!ret)
+		ret = read_uint(node, UPLP_CURRENT_SPEED, &ser->current_speed);
+	if (ret)
+		return log_msg_ret("spe", ret);
+
+	buf = ofnode_read_prop(node, UPLP_REG, &size);
+	if (!buf) {
+		log_warning("Node '%s': Missing 'reg' property\n",
+			    ofnode_get_name(node));
+		return log_msg_ret("reg", -EINVAL);
+	}
+
+	len = decode_addr_size(upl, buf, sizeof(buf), &ser->reg);
+	if (len < 0)
+		return log_msg_ret("buf", len);
+
+	/* set defaults */
+	ser->reg_io_shift = UPLD_REG_IO_SHIFT;
+	ser->reg_offset = UPLD_REG_OFFSET;
+	ser->reg_io_width = UPLD_REG_IO_WIDTH;
+	read_uint(node, UPLP_REG_IO_SHIFT, &ser->reg_io_shift);
+	read_uint(node, UPLP_REG_OFFSET, &ser->reg_offset);
+	read_uint(node, UPLP_REG_IO_WIDTH, &ser->reg_io_width);
+	read_addr(upl, node, UPLP_VIRTUAL_REG, &ser->virtual_reg);
+	ret = ofnode_read_value(node, UPLP_ACCESS_TYPE, access_types,
+				ARRAY_SIZE(access_types), &ser->access_type);
+	if (ret && ret != -ENOENT)
+		return log_msg_ret("ser", ret);
+
+	return 0;
+}
+
+/**
+ * decode_upl_graphics() - Decode graphics node
+ *
+ * @upl: UPL state
+ * @root: Node to decode
+ * Return 0 if OK, -ve on error
+ */
+static int decode_upl_graphics(struct upl *upl, ofnode node)
+{
+	struct upl_graphics *gra = &upl->graphics;
+	const char *buf, *compat;
+	int len, size;
+	int ret;
+
+	compat = ofnode_read_string(node, UPLP_COMPATIBLE);
+	if (!compat) {
+		log_warning("Node '%s': Missing compatible string\n",
+			    ofnode_get_name(node));
+		return log_msg_ret("com", -EINVAL);
+	}
+	if (strcmp(UPLC_GRAPHICS, compat)) {
+		log_warning("Node '%s': Ignoring compatible '%s'\n",
+			    ofnode_get_name(node), compat);
+		return 0;
+	}
+
+	buf = ofnode_read_prop(node, UPLP_REG, &size);
+	if (!buf) {
+		log_warning("Node '%s': Missing 'reg' property\n",
+			    ofnode_get_name(node));
+		return log_msg_ret("reg", -EINVAL);
+	}
+
+	len = decode_addr_size(upl, buf, sizeof(buf), &gra->reg);
+	if (len < 0)
+		return log_msg_ret("buf", len);
+
+	ret = read_uint(node, UPLP_WIDTH, &gra->width);
+	if (!ret)
+		ret = read_uint(node, UPLP_HEIGHT, &gra->height);
+	if (!ret)
+		ret = read_uint(node, UPLP_STRIDE, &gra->stride);
+	if (!ret) {
+		ret = ofnode_read_value(node, UPLP_GRAPHICS_FORMAT,
+					graphics_formats,
+					ARRAY_SIZE(graphics_formats),
+					&gra->format);
+	}
+	if (ret)
+		return log_msg_ret("pro", ret);
+
+	return 0;
+}
+
+int upl_read_handoff(struct upl *upl, oftree tree)
+{
+	ofnode root, node;
+	int ret;
+
+	if (!oftree_valid(tree))
+		return log_msg_ret("tre", -EINVAL);
+
+	root = oftree_root(tree);
+
+	upl_init(upl);
+	ret = decode_root_props(upl, root);
+	if (ret)
+		return log_msg_ret("roo", ret);
+
+	ofnode_for_each_subnode(node, root) {
+		const char *name = ofnode_get_name(node);
+
+		log_debug("decoding '%s'\n", name);
+		if (!strcmp(UPLN_OPTIONS, name)) {
+			ret = decode_upl_params(upl, node);
+			if (ret)
+				return log_msg_ret("opt", ret);
+
+			ret = decode_upl_images(upl, node);
+		} else if (node_matches_at(node, UPLN_MEMORY)) {
+			ret = decode_upl_memory_node(upl, node);
+		} else if (!strcmp(UPLN_MEMORY_MAP, name)) {
+			ret = decode_upl_memmap(upl, node);
+		} else if (!strcmp(UPLN_MEMORY_RESERVED, name)) {
+			ret = decode_upl_memres(upl, node);
+		} else if (node_matches_at(node, UPLN_SERIAL)) {
+			ret = decode_upl_serial(upl, node);
+		} else if (node_matches_at(node, UPLN_GRAPHICS)) {
+			ret = decode_upl_graphics(upl, node);
+		} else {
+			log_debug("Unknown node '%s'\n", name);
+			ret = 0;
+		}
+		if (ret)
+			return log_msg_ret("err", ret);
+	}
+
+	return 0;
+}
diff --git a/configs/sandbox_defconfig b/configs/sandbox_defconfig
index dc5fcdb..484f9e1 100644
--- a/configs/sandbox_defconfig
+++ b/configs/sandbox_defconfig
@@ -16,6 +16,7 @@
 CONFIG_FIT_CIPHER=y
 CONFIG_FIT_VERBOSE=y
 CONFIG_BOOTMETH_ANDROID=y
+CONFIG_UPL=y
 CONFIG_LEGACY_IMAGE_FORMAT=y
 CONFIG_MEASURED_BOOT=y
 CONFIG_BOOTSTAGE=y
diff --git a/include/upl.h b/include/upl.h
new file mode 100644
index 0000000..df644c4
--- /dev/null
+++ b/include/upl.h
@@ -0,0 +1,373 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * UPL handoff generation
+ *
+ * Copyright 2024 Google LLC
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __UPL_WRITE_H
+#define __UPL_WRITE_H
+
+#ifndef USE_HOSTCC
+
+#include <alist.h>
+#include <image.h>
+#include <dm/ofnode_decl.h>
+
+struct unit_test_state;
+
+#define UPLP_ADDRESS_CELLS	"#address-cells"
+#define UPLP_SIZE_CELLS		"#size-cells"
+
+#define UPLN_OPTIONS		"options"
+#define UPLN_UPL_PARAMS		"upl-params"
+#define UPLP_SMBIOS		"smbios"
+#define UPLP_ACPI		"acpi"
+#define UPLP_BOOTMODE		"bootmode"
+#define UPLP_ADDR_WIDTH		"addr-width"
+#define UPLP_ACPI_NVS_SIZE	"acpi-nvs-size"
+
+#define UPLPATH_UPL_IMAGE	"/options/upl-image"
+#define UPLN_UPL_IMAGE		"upl-image"
+#define UPLN_IMAGE		"image"
+#define UPLP_FIT		"fit"
+#define UPLP_CONF_OFFSET	"conf-offset"
+#define UPLP_LOAD		"load"
+#define UPLP_SIZE		"size"
+#define UPLP_OFFSET		"offset"
+#define UPLP_DESCRIPTION	"description"
+
+#define UPLN_MEMORY		"memory"
+#define UPLP_HOTPLUGGABLE	"hotpluggable"
+
+#define UPLPATH_MEMORY_MAP	"/memory-map"
+#define UPLN_MEMORY_MAP		"memory-map"
+#define UPLP_USAGE		"usage"
+
+#define UPLN_MEMORY_RESERVED	"reserved-memory"
+#define UPLPATH_MEMORY_RESERVED	"/reserved-memory"
+#define UPLP_NO_MAP		"no-map"
+
+#define UPLN_SERIAL		"serial"
+#define UPLP_REG		"reg"
+#define UPLP_COMPATIBLE		"compatible"
+#define UPLP_CLOCK_FREQUENCY	"clock-frequency"
+#define UPLP_CURRENT_SPEED	"current-speed"
+#define UPLP_REG_IO_SHIFT	"reg-io-shift"
+#define UPLP_REG_OFFSET		"reg-offset"
+#define UPLP_REG_IO_WIDTH	"reg-io-width"
+#define UPLP_VIRTUAL_REG	"virtual-reg"
+#define UPLP_ACCESS_TYPE	"access-type"
+
+#define UPLN_GRAPHICS		"framebuffer"
+#define UPLC_GRAPHICS		"simple-framebuffer"
+#define UPLP_WIDTH		"width"
+#define UPLP_HEIGHT		"height"
+#define UPLP_STRIDE		"stride"
+#define UPLP_GRAPHICS_FORMAT	"format"
+
+/**
+ * enum upl_boot_mode - Encodes the boot mode
+ *
+ * Each is a bit number from the boot_mode mask
+ */
+enum upl_boot_mode {
+	UPLBM_FULL,
+	UPLBM_MINIMAL,
+	UPLBM_FAST,
+	UPLBM_DIAG,
+	UPLBM_DEFAULT,
+	UPLBM_S2,
+	UPLBM_S3,
+	UPLBM_S4,
+	UPLBM_S5,
+	UPLBM_FACTORY,
+	UPLBM_FLASH,
+	UPLBM_RECOVERY,
+
+	UPLBM_COUNT,
+};
+
+/**
+ * struct upl_image - UPL image informaiton
+ *
+ * @load: Address image was loaded to
+ * @size: Size of image in bytes
+ * @offset: Offset of the image in the FIT (0=none)
+ * @desc: Description of the iamge (taken from the FIT)
+ */
+struct upl_image {
+	ulong load;
+	ulong size;
+	uint offset;
+	const char *description;
+};
+
+/**
+ * struct memregion - Information about a region of memory
+ *
+ * @base: Base address
+ * @size: Size in bytes
+ */
+struct memregion {
+	ulong base;
+	ulong size;
+};
+
+/**
+ * struct upl_mem - Information about physical-memory layout
+ *
+ * TODO: Figure out initial-mapped-area
+ *
+ * @region: Memory region list (struct memregion)
+ * @hotpluggable: true if hotpluggable
+ */
+struct upl_mem {
+	struct alist region;
+	bool hotpluggable;
+};
+
+/**
+ * enum upl_usage - Encodes the usage
+ *
+ * Each is a bit number from the usage mask
+ */
+enum upl_usage {
+	UPLUS_ACPI_RECLAIM,
+	UPLUS_ACPI_NVS,
+	UPLUS_BOOT_CODE,
+	UPLUS_BOOT_DATA,
+	UPLUS_RUNTIME_CODE,
+	UPLUS_RUNTIME_DATA,
+	UPLUS_COUNT
+};
+
+/**
+ * struct upl_memmap - Information about logical-memory layout
+ *
+ * @name: Node name to use
+ * @region: Memory region list (struct memregion)
+ * @usage: Memory-usage mask (enum upl_usage)
+ */
+struct upl_memmap {
+	const char *name;
+	struct alist region;
+	uint usage;
+};
+
+/**
+ * struct upl_memres - Reserved memory
+ *
+ * @name: Node name to use
+ * @region: Reserved memory region list (struct memregion)
+ * @no_map: true to indicate that a virtual mapping must not be created
+ */
+struct upl_memres {
+	const char *name;
+	struct alist region;
+	bool no_map;
+};
+
+enum upl_serial_access_type {
+	UPLSAT_MMIO,
+	UPLSAT_IO,
+};
+
+/* serial defaults */
+enum {
+	UPLD_REG_IO_SHIFT	= 0,
+	UPLD_REG_OFFSET		= 0,
+	UPLD_REG_IO_WIDTH	= 1,
+};
+
+/**
+ * enum upl_access_type - Access types
+ *
+ * @UPLAT_MMIO: Memory-mapped I/O
+ * @UPLAT_IO: Separate I/O
+ */
+enum upl_access_type {
+	UPLAT_MMIO,
+	UPLAT_IO,
+};
+
+/**
+ * struct upl_serial - Serial console
+ *
+ * @compatible: Compatible string (NULL if there is no serial console)
+ * @clock_frequency: Input clock frequency of UART
+ * @current_speed: Current baud rate of UART
+ * @reg: List of base address and size of registers (struct memregion)
+ * @reg_shift_log2: log2 of distance between each register
+ * @reg_offset: Offset of registers from the base address
+ * @reg_width: Register width in bytes
+ * @virtual_reg: Virtual register access (0 for none)
+ * @access_type: Register access type to use
+ */
+struct upl_serial {
+	const char *compatible;
+	uint clock_frequency;
+	uint current_speed;
+	struct alist reg;
+	uint reg_io_shift;
+	uint reg_offset;
+	uint reg_io_width;
+	ulong virtual_reg;
+	enum upl_serial_access_type access_type;
+};
+
+/**
+ * enum upl_graphics_format - Graphics formats
+ *
+ * @UPLGF_ARGB32: 32bpp format using 0xaarrggbb
+ * @UPLGF_ABGR32: 32bpp format using 0xaabbggrr
+ * @UPLGF_ARGB64: 64bpp format using 0xaaaabbbbggggrrrr
+ */
+enum upl_graphics_format {
+	UPLGF_ARGB32,
+	UPLGF_ABGR32,
+	UPLGF_ABGR64,
+};
+
+/**
+ * @reg: List of base address and size of registers (struct memregion)
+ * @width: Width of display in pixels
+ * @height: Height of display in pixels
+ * @stride: Number of bytes from one line to the next
+ * @format: Pixel format
+ */
+struct upl_graphics {
+	struct alist reg;
+	uint width;
+	uint height;
+	uint stride;
+	enum upl_graphics_format format;
+};
+
+/*
+ * Information about the UPL state
+ *
+ * @addr_cells: Number of address cells used in the handoff
+ * @size_cells: Number of size cells used in the handoff
+ * @bootmode: Boot-mode mask (enum upl_boot_mode)
+ * @fit: Address of FIT image that was loaded
+ * @conf_offset: Offset in FIT of the configuration that was selected
+ * @addr_width: Adress-bus width of machine, e.g. 46 for 46 bits
+ * @acpi_nvs_size: Size of the ACPI non-volatile-storage area in bytes
+ * @image: Information about each image (struct upl_image)
+ * @mem: Information about physical-memory regions (struct upl_mem)
+ * @nennap: Information about logical-memory regions (struct upl_memmap)
+ * @nennap: Information about reserved-memory regions (struct upl_memres)
+ */
+struct upl {
+	int addr_cells;
+	int size_cells;
+
+	ulong smbios;
+	ulong acpi;
+	uint bootmode;
+	ulong fit;
+	uint conf_offset;
+	uint addr_width;
+	uint acpi_nvs_size;
+
+	struct alist image;
+	struct alist mem;
+	struct alist memmap;
+	struct alist memres;
+	struct upl_serial serial;
+	struct upl_graphics graphics;
+};
+
+/**
+ * upl_write_handoff() - Write a Unversal Payload handoff structure
+ *
+ * upl: UPL state to write
+ * @root: root node to write it to
+ * @skip_existing: Avoid recreating any nodes which already exist in the
+ * devicetree. For example, if there is a serial node, just leave it alone,
+ * since don't need to create a new one
+ * Return: 0 on success, -ve on error
+ */
+int upl_write_handoff(const struct upl *upl, ofnode root, bool skip_existing);
+
+/**
+ * upl_create_handoff_tree() - Write a Unversal Payload handoff structure
+ *
+ * upl: UPL state to write
+ * @treep: Returns a new tree containing the handoff
+ * Return: 0 on success, -ve on error
+ */
+int upl_create_handoff_tree(const struct upl *upl, oftree *treep);
+
+/**
+ * upl_read_handoff() - Read a Unversal Payload handoff structure
+ *
+ * upl: UPL state to read into
+ * @tree: Devicetree containing the data to read
+ * Return: 0 on success, -ve on error
+ */
+int upl_read_handoff(struct upl *upl, oftree tree);
+#endif /* USE_HOSTCC */
+
+#if CONFIG_IS_ENABLED(UPL) && defined(CONFIG_SPL_BUILD)
+
+/**
+ * upl_set_fit_info() - Set up basic info about the FIT
+ *
+ * @fit: Address of FIT
+ * @conf_offset: Configuration node being used
+ * @entry_addr: Entry address for next phase
+ */
+void upl_set_fit_info(ulong fit, int conf_offset, ulong entry_addr);
+
+/**
+ * upl_set_fit_addr() - Set up the address of the FIT
+ *
+ * @fit: Address of FIT
+ */
+void upl_set_fit_addr(ulong fit);
+
+#else
+static inline void upl_set_fit_addr(ulong fit) {}
+static inline void upl_set_fit_info(ulong fit, int conf_offset,
+				    ulong entry_addr) {}
+#endif /* UPL && SPL */
+
+/**
+ * _upl_add_image() - Internal function to add a new image to the UPL
+ *
+ * @node: Image node offset in FIT
+ * @load_addr: Address to which images was loaded
+ * @size: Image size in bytes
+ * @desc: Description of image
+ * Return: 0 if OK, -ENOMEM if out of memory
+ */
+int _upl_add_image(int node, ulong load_addr, ulong size, const char *desc);
+
+/**
+ * upl_add_image() - Add a new image to the UPL
+ *
+ * @fit: Pointer to FIT
+ * @node: Image node offset in FIT
+ * @load_addr: Address to which images was loaded
+ * @size: Image size in bytes
+ * Return: 0 if OK, -ENOMEM if out of memory
+ */
+static inline int upl_add_image(const void *fit, int node, ulong load_addr,
+				ulong size)
+{
+	if (CONFIG_IS_ENABLED(UPL) && IS_ENABLED(CONFIG_SPL_BUILD)) {
+		const char *desc = fdt_getprop(fit, node, FIT_DESC_PROP, NULL);
+
+		return _upl_add_image(node, load_addr, size, desc);
+	}
+
+	return 0;
+}
+
+/** upl_init() - Set up a UPL struct */
+void upl_init(struct upl *upl);
+
+#endif /* __UPL_WRITE_H */