Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1398 insertions, 0 deletions

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
new file mode 100644
index 000000000..d1a68b6d0
--- /dev/null
+++ b/drivers/of/fdt.c
@@ -0,0 +1,1398 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Functions for working with the Flattened Device Tree data format
+ *
+ * Copyright 2009 Benjamin Herrenschmidt, IBM Corp
+ * benh@kernel.crashing.org
+ */
+
+#define pr_fmt(fmt)	"OF: fdt: " fmt
+
+#include <linux/crash_dump.h>
+#include <linux/crc32.h>
+#include <linux/kernel.h>
+#include <linux/initrd.h>
+#include <linux/memblock.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/of_reserved_mem.h>
+#include <linux/sizes.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/libfdt.h>
+#include <linux/debugfs.h>
+#include <linux/serial_core.h>
+#include <linux/sysfs.h>
+#include <linux/random.h>
+
+#include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
+#include <asm/page.h>
+
+#include "of_private.h"
+
+/*
+ * of_fdt_limit_memory - limit the number of regions in the /memory node
+ * @limit: maximum entries
+ *
+ * Adjust the flattened device tree to have at most 'limit' number of
+ * memory entries in the /memory node. This function may be called
+ * any time after initial_boot_param is set.
+ */
+void __init of_fdt_limit_memory(int limit)
+{
+	int memory;
+	int len;
+	const void *val;
+	int nr_address_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
+	int nr_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
+	const __be32 *addr_prop;
+	const __be32 *size_prop;
+	int root_offset;
+	int cell_size;
+
+	root_offset = fdt_path_offset(initial_boot_params, "/");
+	if (root_offset < 0)
+		return;
+
+	addr_prop = fdt_getprop(initial_boot_params, root_offset,
+				"#address-cells", NULL);
+	if (addr_prop)
+		nr_address_cells = fdt32_to_cpu(*addr_prop);
+
+	size_prop = fdt_getprop(initial_boot_params, root_offset,
+				"#size-cells", NULL);
+	if (size_prop)
+		nr_size_cells = fdt32_to_cpu(*size_prop);
+
+	cell_size = sizeof(uint32_t)*(nr_address_cells + nr_size_cells);
+
+	memory = fdt_path_offset(initial_boot_params, "/memory");
+	if (memory > 0) {
+		val = fdt_getprop(initial_boot_params, memory, "reg", &len);
+		if (len > limit*cell_size) {
+			len = limit*cell_size;
+			pr_debug("Limiting number of entries to %d\n", limit);
+			fdt_setprop(initial_boot_params, memory, "reg", val,
+					len);
+		}
+	}
+}
+
+static bool of_fdt_device_is_available(const void *blob, unsigned long node)
+{
+	const char *status = fdt_getprop(blob, node, "status", NULL);
+
+	if (!status)
+		return true;
+
+	if (!strcmp(status, "ok") || !strcmp(status, "okay"))
+		return true;
+
+	return false;
+}
+
+static void *unflatten_dt_alloc(void **mem, unsigned long size,
+				       unsigned long align)
+{
+	void *res;
+
+	*mem = PTR_ALIGN(*mem, align);
+	res = *mem;
+	*mem += size;
+
+	return res;
+}
+
+static void populate_properties(const void *blob,
+				int offset,
+				void **mem,
+				struct device_node *np,
+				const char *nodename,
+				bool dryrun)
+{
+	struct property *pp, **pprev = NULL;
+	int cur;
+	bool has_name = false;
+
+	pprev = &np->properties;
+	for (cur = fdt_first_property_offset(blob, offset);
+	     cur >= 0;
+	     cur = fdt_next_property_offset(blob, cur)) {
+		const __be32 *val;
+		const char *pname;
+		u32 sz;
+
+		val = fdt_getprop_by_offset(blob, cur, &pname, &sz);
+		if (!val) {
+			pr_warn("Cannot locate property at 0x%x\n", cur);
+			continue;
+		}
+
+		if (!pname) {
+			pr_warn("Cannot find property name at 0x%x\n", cur);
+			continue;
+		}
+
+		if (!strcmp(pname, "name"))
+			has_name = true;
+
+		pp = unflatten_dt_alloc(mem, sizeof(struct property),
+					__alignof__(struct property));
+		if (dryrun)
+			continue;
+
+		/* We accept flattened tree phandles either in
+		 * ePAPR-style "phandle" properties, or the
+		 * legacy "linux,phandle" properties.  If both
+		 * appear and have different values, things
+		 * will get weird. Don't do that.
+		 */
+		if (!strcmp(pname, "phandle") ||
+		    !strcmp(pname, "linux,phandle")) {
+			if (!np->phandle)
+				np->phandle = be32_to_cpup(val);
+		}
+
+		/* And we process the "ibm,phandle" property
+		 * used in pSeries dynamic device tree
+		 * stuff
+		 */
+		if (!strcmp(pname, "ibm,phandle"))
+			np->phandle = be32_to_cpup(val);
+
+		pp->name   = (char *)pname;
+		pp->length = sz;
+		pp->value  = (__be32 *)val;
+		*pprev     = pp;
+		pprev      = &pp->next;
+	}
+
+	/* With version 0x10 we may not have the name property,
+	 * recreate it here from the unit name if absent
+	 */
+	if (!has_name) {
+		const char *p = nodename, *ps = p, *pa = NULL;
+		int len;
+
+		while (*p) {
+			if ((*p) == '@')
+				pa = p;
+			else if ((*p) == '/')
+				ps = p + 1;
+			p++;
+		}
+
+		if (pa < ps)
+			pa = p;
+		len = (pa - ps) + 1;
+		pp = unflatten_dt_alloc(mem, sizeof(struct property) + len,
+					__alignof__(struct property));
+		if (!dryrun) {
+			pp->name   = "name";
+			pp->length = len;
+			pp->value  = pp + 1;
+			*pprev     = pp;
+			memcpy(pp->value, ps, len - 1);
+			((char *)pp->value)[len - 1] = 0;
+			pr_debug("fixed up name for %s -> %s\n",
+				 nodename, (char *)pp->value);
+		}
+	}
+}
+
+static int populate_node(const void *blob,
+			  int offset,
+			  void **mem,
+			  struct device_node *dad,
+			  struct device_node **pnp,
+			  bool dryrun)
+{
+	struct device_node *np;
+	const char *pathp;
+	int len;
+
+	pathp = fdt_get_name(blob, offset, &len);
+	if (!pathp) {
+		*pnp = NULL;
+		return len;
+	}
+
+	len++;
+
+	np = unflatten_dt_alloc(mem, sizeof(struct device_node) + len,
+				__alignof__(struct device_node));
+	if (!dryrun) {
+		char *fn;
+		of_node_init(np);
+		np->full_name = fn = ((char *)np) + sizeof(*np);
+
+		memcpy(fn, pathp, len);
+
+		if (dad != NULL) {
+			np->parent = dad;
+			np->sibling = dad->child;
+			dad->child = np;
+		}
+	}
+
+	populate_properties(blob, offset, mem, np, pathp, dryrun);
+	if (!dryrun) {
+		np->name = of_get_property(np, "name", NULL);
+		if (!np->name)
+			np->name = "<NULL>";
+	}
+
+	*pnp = np;
+	return 0;
+}
+
+static void reverse_nodes(struct device_node *parent)
+{
+	struct device_node *child, *next;
+
+	/* In-depth first */
+	child = parent->child;
+	while (child) {
+		reverse_nodes(child);
+
+		child = child->sibling;
+	}
+
+	/* Reverse the nodes in the child list */
+	child = parent->child;
+	parent->child = NULL;
+	while (child) {
+		next = child->sibling;
+
+		child->sibling = parent->child;
+		parent->child = child;
+		child = next;
+	}
+}
+
+/**
+ * unflatten_dt_nodes - Alloc and populate a device_node from the flat tree
+ * @blob: The parent device tree blob
+ * @mem: Memory chunk to use for allocating device nodes and properties
+ * @dad: Parent struct device_node
+ * @nodepp: The device_node tree created by the call
+ *
+ * Return: The size of unflattened device tree or error code
+ */
+static int unflatten_dt_nodes(const void *blob,
+			      void *mem,
+			      struct device_node *dad,
+			      struct device_node **nodepp)
+{
+	struct device_node *root;
+	int offset = 0, depth = 0, initial_depth = 0;
+#define FDT_MAX_DEPTH	64
+	struct device_node *nps[FDT_MAX_DEPTH];
+	void *base = mem;
+	bool dryrun = !base;
+	int ret;
+
+	if (nodepp)
+		*nodepp = NULL;
+
+	/*
+	 * We're unflattening device sub-tree if @dad is valid. There are
+	 * possibly multiple nodes in the first level of depth. We need
+	 * set @depth to 1 to make fdt_next_node() happy as it bails
+	 * immediately when negative @depth is found. Otherwise, the device
+	 * nodes except the first one won't be unflattened successfully.
+	 */
+	if (dad)
+		depth = initial_depth = 1;
+
+	root = dad;
+	nps[depth] = dad;
+
+	for (offset = 0;
+	     offset >= 0 && depth >= initial_depth;
+	     offset = fdt_next_node(blob, offset, &depth)) {
+		if (WARN_ON_ONCE(depth >= FDT_MAX_DEPTH - 1))
+			continue;
+
+		if (!IS_ENABLED(CONFIG_OF_KOBJ) &&
+		    !of_fdt_device_is_available(blob, offset))
+			continue;
+
+		ret = populate_node(blob, offset, &mem, nps[depth],
+				   &nps[depth+1], dryrun);
+		if (ret < 0)
+			return ret;
+
+		if (!dryrun && nodepp && !*nodepp)
+			*nodepp = nps[depth+1];
+		if (!dryrun && !root)
+			root = nps[depth+1];
+	}
+
+	if (offset < 0 && offset != -FDT_ERR_NOTFOUND) {
+		pr_err("Error %d processing FDT\n", offset);
+		return -EINVAL;
+	}
+
+	/*
+	 * Reverse the child list. Some drivers assumes node order matches .dts
+	 * node order
+	 */
+	if (!dryrun)
+		reverse_nodes(root);
+
+	return mem - base;
+}
+
+/**
+ * __unflatten_device_tree - create tree of device_nodes from flat blob
+ * @blob: The blob to expand
+ * @dad: Parent device node
+ * @mynodes: The device_node tree created by the call
+ * @dt_alloc: An allocator that provides a virtual address to memory
+ * for the resulting tree
+ * @detached: if true set OF_DETACHED on @mynodes
+ *
+ * unflattens a device-tree, creating the tree of struct device_node. It also
+ * fills the "name" and "type" pointers of the nodes so the normal device-tree
+ * walking functions can be used.
+ *
+ * Return: NULL on failure or the memory chunk containing the unflattened
+ * device tree on success.
+ */
+void *__unflatten_device_tree(const void *blob,
+			      struct device_node *dad,
+			      struct device_node **mynodes,
+			      void *(*dt_alloc)(u64 size, u64 align),
+			      bool detached)
+{
+	int size;
+	void *mem;
+	int ret;
+
+	if (mynodes)
+		*mynodes = NULL;
+
+	pr_debug(" -> unflatten_device_tree()\n");
+
+	if (!blob) {
+		pr_debug("No device tree pointer\n");
+		return NULL;
+	}
+
+	pr_debug("Unflattening device tree:\n");
+	pr_debug("magic: %08x\n", fdt_magic(blob));
+	pr_debug("size: %08x\n", fdt_totalsize(blob));
+	pr_debug("version: %08x\n", fdt_version(blob));
+
+	if (fdt_check_header(blob)) {
+		pr_err("Invalid device tree blob header\n");
+		return NULL;
+	}
+
+	/* First pass, scan for size */
+	size = unflatten_dt_nodes(blob, NULL, dad, NULL);
+	if (size <= 0)
+		return NULL;
+
+	size = ALIGN(size, 4);
+	pr_debug("  size is %d, allocating...\n", size);
+
+	/* Allocate memory for the expanded device tree */
+	mem = dt_alloc(size + 4, __alignof__(struct device_node));
+	if (!mem)
+		return NULL;
+
+	memset(mem, 0, size);
+
+	*(__be32 *)(mem + size) = cpu_to_be32(0xdeadbeef);
+
+	pr_debug("  unflattening %p...\n", mem);
+
+	/* Second pass, do actual unflattening */
+	ret = unflatten_dt_nodes(blob, mem, dad, mynodes);
+
+	if (be32_to_cpup(mem + size) != 0xdeadbeef)
+		pr_warn("End of tree marker overwritten: %08x\n",
+			be32_to_cpup(mem + size));
+
+	if (ret <= 0)
+		return NULL;
+
+	if (detached && mynodes && *mynodes) {
+		of_node_set_flag(*mynodes, OF_DETACHED);
+		pr_debug("unflattened tree is detached\n");
+	}
+
+	pr_debug(" <- unflatten_device_tree()\n");
+	return mem;
+}
+
+static void *kernel_tree_alloc(u64 size, u64 align)
+{
+	return kzalloc(size, GFP_KERNEL);
+}
+
+static DEFINE_MUTEX(of_fdt_unflatten_mutex);
+
+/**
+ * of_fdt_unflatten_tree - create tree of device_nodes from flat blob
+ * @blob: Flat device tree blob
+ * @dad: Parent device node
+ * @mynodes: The device tree created by the call
+ *
+ * unflattens the device-tree passed by the firmware, creating the
+ * tree of struct device_node. It also fills the "name" and "type"
+ * pointers of the nodes so the normal device-tree walking functions
+ * can be used.
+ *
+ * Return: NULL on failure or the memory chunk containing the unflattened
+ * device tree on success.
+ */
+void *of_fdt_unflatten_tree(const unsigned long *blob,
+			    struct device_node *dad,
+			    struct device_node **mynodes)
+{
+	void *mem;
+
+	mutex_lock(&of_fdt_unflatten_mutex);
+	mem = __unflatten_device_tree(blob, dad, mynodes, &kernel_tree_alloc,
+				      true);
+	mutex_unlock(&of_fdt_unflatten_mutex);
+
+	return mem;
+}
+EXPORT_SYMBOL_GPL(of_fdt_unflatten_tree);
+
+/* Everything below here references initial_boot_params directly. */
+int __initdata dt_root_addr_cells;
+int __initdata dt_root_size_cells;
+
+void *initial_boot_params __ro_after_init;
+
+#ifdef CONFIG_OF_EARLY_FLATTREE
+
+static u32 of_fdt_crc32;
+
+static int __init early_init_dt_reserve_memory(phys_addr_t base,
+					       phys_addr_t size, bool nomap)
+{
+	if (nomap) {
+		/*
+		 * If the memory is already reserved (by another region), we
+		 * should not allow it to be marked nomap, but don't worry
+		 * if the region isn't memory as it won't be mapped.
+		 */
+		if (memblock_overlaps_region(&memblock.memory, base, size) &&
+		    memblock_is_region_reserved(base, size))
+			return -EBUSY;
+
+		return memblock_mark_nomap(base, size);
+	}
+	return memblock_reserve(base, size);
+}
+
+/*
+ * __reserved_mem_reserve_reg() - reserve all memory described in 'reg' property
+ */
+static int __init __reserved_mem_reserve_reg(unsigned long node,
+					     const char *uname)
+{
+	int t_len = (dt_root_addr_cells + dt_root_size_cells) * sizeof(__be32);
+	phys_addr_t base, size;
+	int len;
+	const __be32 *prop;
+	int first = 1;
+	bool nomap;
+
+	prop = of_get_flat_dt_prop(node, "reg", &len);
+	if (!prop)
+		return -ENOENT;
+
+	if (len && len % t_len != 0) {
+		pr_err("Reserved memory: invalid reg property in '%s', skipping node.\n",
+		       uname);
+		return -EINVAL;
+	}
+
+	nomap = of_get_flat_dt_prop(node, "no-map", NULL) != NULL;
+
+	while (len >= t_len) {
+		base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+		size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+		if (size &&
+		    early_init_dt_reserve_memory(base, size, nomap) == 0)
+			pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
+				uname, &base, (unsigned long)(size / SZ_1M));
+		else
+			pr_err("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
+			       uname, &base, (unsigned long)(size / SZ_1M));
+
+		len -= t_len;
+		if (first) {
+			fdt_reserved_mem_save_node(node, uname, base, size);
+			first = 0;
+		}
+	}
+	return 0;
+}
+
+/*
+ * __reserved_mem_check_root() - check if #size-cells, #address-cells provided
+ * in /reserved-memory matches the values supported by the current implementation,
+ * also check if ranges property has been provided
+ */
+static int __init __reserved_mem_check_root(unsigned long node)
+{
+	const __be32 *prop;
+
+	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
+	if (!prop || be32_to_cpup(prop) != dt_root_size_cells)
+		return -EINVAL;
+
+	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
+	if (!prop || be32_to_cpup(prop) != dt_root_addr_cells)
+		return -EINVAL;
+
+	prop = of_get_flat_dt_prop(node, "ranges", NULL);
+	if (!prop)
+		return -EINVAL;
+	return 0;
+}
+
+/*
+ * fdt_scan_reserved_mem() - scan a single FDT node for reserved memory
+ */
+static int __init fdt_scan_reserved_mem(void)
+{
+	int node, child;
+	const void *fdt = initial_boot_params;
+
+	node = fdt_path_offset(fdt, "/reserved-memory");
+	if (node < 0)
+		return -ENODEV;
+
+	if (__reserved_mem_check_root(node) != 0) {
+		pr_err("Reserved memory: unsupported node format, ignoring\n");
+		return -EINVAL;
+	}
+
+	fdt_for_each_subnode(child, fdt, node) {
+		const char *uname;
+		int err;
+
+		if (!of_fdt_device_is_available(fdt, child))
+			continue;
+
+		uname = fdt_get_name(fdt, child, NULL);
+
+		err = __reserved_mem_reserve_reg(child, uname);
+		if (err == -ENOENT && of_get_flat_dt_prop(child, "size", NULL))
+			fdt_reserved_mem_save_node(child, uname, 0, 0);
+	}
+	return 0;
+}
+
+/*
+ * fdt_reserve_elfcorehdr() - reserves memory for elf core header
+ *
+ * This function reserves the memory occupied by an elf core header
+ * described in the device tree. This region contains all the
+ * information about primary kernel's core image and is used by a dump
+ * capture kernel to access the system memory on primary kernel.
+ */
+static void __init fdt_reserve_elfcorehdr(void)
+{
+	if (!IS_ENABLED(CONFIG_CRASH_DUMP) || !elfcorehdr_size)
+		return;
+
+	if (memblock_is_region_reserved(elfcorehdr_addr, elfcorehdr_size)) {
+		pr_warn("elfcorehdr is overlapped\n");
+		return;
+	}
+
+	memblock_reserve(elfcorehdr_addr, elfcorehdr_size);
+
+	pr_info("Reserving %llu KiB of memory at 0x%llx for elfcorehdr\n",
+		elfcorehdr_size >> 10, elfcorehdr_addr);
+}
+
+/**
+ * early_init_fdt_scan_reserved_mem() - create reserved memory regions
+ *
+ * This function grabs memory from early allocator for device exclusive use
+ * defined in device tree structures. It should be called by arch specific code
+ * once the early allocator (i.e. memblock) has been fully activated.
+ */
+void __init early_init_fdt_scan_reserved_mem(void)
+{
+	int n;
+	u64 base, size;
+
+	if (!initial_boot_params)
+		return;
+
+	/* Process header /memreserve/ fields */
+	for (n = 0; ; n++) {
+		fdt_get_mem_rsv(initial_boot_params, n, &base, &size);
+		if (!size)
+			break;
+		memblock_reserve(base, size);
+	}
+
+	fdt_scan_reserved_mem();
+	fdt_reserve_elfcorehdr();
+	fdt_init_reserved_mem();
+}
+
+/**
+ * early_init_fdt_reserve_self() - reserve the memory used by the FDT blob
+ */
+void __init early_init_fdt_reserve_self(void)
+{
+	if (!initial_boot_params)
+		return;
+
+	/* Reserve the dtb region */
+	memblock_reserve(__pa(initial_boot_params),
+			 fdt_totalsize(initial_boot_params));
+}
+
+/**
+ * of_scan_flat_dt - scan flattened tree blob and call callback on each.
+ * @it: callback function
+ * @data: context data pointer
+ *
+ * This function is used to scan the flattened device-tree, it is
+ * used to extract the memory information at boot before we can
+ * unflatten the tree
+ */
+int __init of_scan_flat_dt(int (*it)(unsigned long node,
+				     const char *uname, int depth,
+				     void *data),
+			   void *data)
+{
+	const void *blob = initial_boot_params;
+	const char *pathp;
+	int offset, rc = 0, depth = -1;
+
+	if (!blob)
+		return 0;
+
+	for (offset = fdt_next_node(blob, -1, &depth);
+	     offset >= 0 && depth >= 0 && !rc;
+	     offset = fdt_next_node(blob, offset, &depth)) {
+
+		pathp = fdt_get_name(blob, offset, NULL);
+		rc = it(offset, pathp, depth, data);
+	}
+	return rc;
+}
+
+/**
+ * of_scan_flat_dt_subnodes - scan sub-nodes of a node call callback on each.
+ * @parent: parent node
+ * @it: callback function
+ * @data: context data pointer
+ *
+ * This function is used to scan sub-nodes of a node.
+ */
+int __init of_scan_flat_dt_subnodes(unsigned long parent,
+				    int (*it)(unsigned long node,
+					      const char *uname,
+					      void *data),
+				    void *data)
+{
+	const void *blob = initial_boot_params;
+	int node;
+
+	fdt_for_each_subnode(node, blob, parent) {
+		const char *pathp;
+		int rc;
+
+		pathp = fdt_get_name(blob, node, NULL);
+		rc = it(node, pathp, data);
+		if (rc)
+			return rc;
+	}
+	return 0;
+}
+
+/**
+ * of_get_flat_dt_subnode_by_name - get the subnode by given name
+ *
+ * @node: the parent node
+ * @uname: the name of subnode
+ * @return offset of the subnode, or -FDT_ERR_NOTFOUND if there is none
+ */
+
+int __init of_get_flat_dt_subnode_by_name(unsigned long node, const char *uname)
+{
+	return fdt_subnode_offset(initial_boot_params, node, uname);
+}
+
+/*
+ * of_get_flat_dt_root - find the root node in the flat blob
+ */
+unsigned long __init of_get_flat_dt_root(void)
+{
+	return 0;
+}
+
+/*
+ * of_get_flat_dt_prop - Given a node in the flat blob, return the property ptr
+ *
+ * This function can be used within scan_flattened_dt callback to get
+ * access to properties
+ */
+const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
+				       int *size)
+{
+	return fdt_getprop(initial_boot_params, node, name, size);
+}
+
+/**
+ * of_fdt_is_compatible - Return true if given node from the given blob has
+ * compat in its compatible list
+ * @blob: A device tree blob
+ * @node: node to test
+ * @compat: compatible string to compare with compatible list.
+ *
+ * Return: a non-zero value on match with smaller values returned for more
+ * specific compatible values.
+ */
+static int of_fdt_is_compatible(const void *blob,
+		      unsigned long node, const char *compat)
+{
+	const char *cp;
+	int cplen;
+	unsigned long l, score = 0;
+
+	cp = fdt_getprop(blob, node, "compatible", &cplen);
+	if (cp == NULL)
+		return 0;
+	while (cplen > 0) {
+		score++;
+		if (of_compat_cmp(cp, compat, strlen(compat)) == 0)
+			return score;
+		l = strlen(cp) + 1;
+		cp += l;
+		cplen -= l;
+	}
+
+	return 0;
+}
+
+/**
+ * of_flat_dt_is_compatible - Return true if given node has compat in compatible list
+ * @node: node to test
+ * @compat: compatible string to compare with compatible list.
+ */
+int __init of_flat_dt_is_compatible(unsigned long node, const char *compat)
+{
+	return of_fdt_is_compatible(initial_boot_params, node, compat);
+}
+
+/*
+ * of_flat_dt_match - Return true if node matches a list of compatible values
+ */
+static int __init of_flat_dt_match(unsigned long node, const char *const *compat)
+{
+	unsigned int tmp, score = 0;
+
+	if (!compat)
+		return 0;
+
+	while (*compat) {
+		tmp = of_fdt_is_compatible(initial_boot_params, node, *compat);
+		if (tmp && (score == 0 || (tmp < score)))
+			score = tmp;
+		compat++;
+	}
+
+	return score;
+}
+
+/*
+ * of_get_flat_dt_phandle - Given a node in the flat blob, return the phandle
+ */
+uint32_t __init of_get_flat_dt_phandle(unsigned long node)
+{
+	return fdt_get_phandle(initial_boot_params, node);
+}
+
+const char * __init of_flat_dt_get_machine_name(void)
+{
+	const char *name;
+	unsigned long dt_root = of_get_flat_dt_root();
+
+	name = of_get_flat_dt_prop(dt_root, "model", NULL);
+	if (!name)
+		name = of_get_flat_dt_prop(dt_root, "compatible", NULL);
+	return name;
+}
+
+/**
+ * of_flat_dt_match_machine - Iterate match tables to find matching machine.
+ *
+ * @default_match: A machine specific ptr to return in case of no match.
+ * @get_next_compat: callback function to return next compatible match table.
+ *
+ * Iterate through machine match tables to find the best match for the machine
+ * compatible string in the FDT.
+ */
+const void * __init of_flat_dt_match_machine(const void *default_match,
+		const void * (*get_next_compat)(const char * const**))
+{
+	const void *data = NULL;
+	const void *best_data = default_match;
+	const char *const *compat;
+	unsigned long dt_root;
+	unsigned int best_score = ~1, score = 0;
+
+	dt_root = of_get_flat_dt_root();
+	while ((data = get_next_compat(&compat))) {
+		score = of_flat_dt_match(dt_root, compat);
+		if (score > 0 && score < best_score) {
+			best_data = data;
+			best_score = score;
+		}
+	}
+	if (!best_data) {
+		const char *prop;
+		int size;
+
+		pr_err("\n unrecognized device tree list:\n[ ");
+
+		prop = of_get_flat_dt_prop(dt_root, "compatible", &size);
+		if (prop) {
+			while (size > 0) {
+				printk("'%s' ", prop);
+				size -= strlen(prop) + 1;
+				prop += strlen(prop) + 1;
+			}
+		}
+		printk("]\n\n");
+		return NULL;
+	}
+
+	pr_info("Machine model: %s\n", of_flat_dt_get_machine_name());
+
+	return best_data;
+}
+
+static void __early_init_dt_declare_initrd(unsigned long start,
+					   unsigned long end)
+{
+	/* ARM64 would cause a BUG to occur here when CONFIG_DEBUG_VM is
+	 * enabled since __va() is called too early. ARM64 does make use
+	 * of phys_initrd_start/phys_initrd_size so we can skip this
+	 * conversion.
+	 */
+	if (!IS_ENABLED(CONFIG_ARM64)) {
+		initrd_start = (unsigned long)__va(start);
+		initrd_end = (unsigned long)__va(end);
+		initrd_below_start_ok = 1;
+	}
+}
+
+/**
+ * early_init_dt_check_for_initrd - Decode initrd location from flat tree
+ * @node: reference to node containing initrd location ('chosen')
+ */
+static void __init early_init_dt_check_for_initrd(unsigned long node)
+{
+	u64 start, end;
+	int len;
+	const __be32 *prop;
+
+	if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
+		return;
+
+	pr_debug("Looking for initrd properties... ");
+
+	prop = of_get_flat_dt_prop(node, "linux,initrd-start", &len);
+	if (!prop)
+		return;
+	start = of_read_number(prop, len/4);
+
+	prop = of_get_flat_dt_prop(node, "linux,initrd-end", &len);
+	if (!prop)
+		return;
+	end = of_read_number(prop, len/4);
+	if (start > end)
+		return;
+
+	__early_init_dt_declare_initrd(start, end);
+	phys_initrd_start = start;
+	phys_initrd_size = end - start;
+
+	pr_debug("initrd_start=0x%llx  initrd_end=0x%llx\n", start, end);
+}
+
+/**
+ * early_init_dt_check_for_elfcorehdr - Decode elfcorehdr location from flat
+ * tree
+ * @node: reference to node containing elfcorehdr location ('chosen')
+ */
+static void __init early_init_dt_check_for_elfcorehdr(unsigned long node)
+{
+	const __be32 *prop;
+	int len;
+
+	if (!IS_ENABLED(CONFIG_CRASH_DUMP))
+		return;
+
+	pr_debug("Looking for elfcorehdr property... ");
+
+	prop = of_get_flat_dt_prop(node, "linux,elfcorehdr", &len);
+	if (!prop || (len < (dt_root_addr_cells + dt_root_size_cells)))
+		return;
+
+	elfcorehdr_addr = dt_mem_next_cell(dt_root_addr_cells, &prop);
+	elfcorehdr_size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+	pr_debug("elfcorehdr_start=0x%llx elfcorehdr_size=0x%llx\n",
+		 elfcorehdr_addr, elfcorehdr_size);
+}
+
+static unsigned long chosen_node_offset = -FDT_ERR_NOTFOUND;
+
+/*
+ * The main usage of linux,usable-memory-range is for crash dump kernel.
+ * Originally, the number of usable-memory regions is one. Now there may
+ * be two regions, low region and high region.
+ * To make compatibility with existing user-space and older kdump, the low
+ * region is always the last range of linux,usable-memory-range if exist.
+ */
+#define MAX_USABLE_RANGES		2
+
+/**
+ * early_init_dt_check_for_usable_mem_range - Decode usable memory range
+ * location from flat tree
+ */
+void __init early_init_dt_check_for_usable_mem_range(void)
+{
+	struct memblock_region rgn[MAX_USABLE_RANGES] = {0};
+	const __be32 *prop, *endp;
+	int len, i;
+	unsigned long node = chosen_node_offset;
+
+	if ((long)node < 0)
+		return;
+
+	pr_debug("Looking for usable-memory-range property... ");
+
+	prop = of_get_flat_dt_prop(node, "linux,usable-memory-range", &len);
+	if (!prop || (len % (dt_root_addr_cells + dt_root_size_cells)))
+		return;
+
+	endp = prop + (len / sizeof(__be32));
+	for (i = 0; i < MAX_USABLE_RANGES && prop < endp; i++) {
+		rgn[i].base = dt_mem_next_cell(dt_root_addr_cells, &prop);
+		rgn[i].size = dt_mem_next_cell(dt_root_size_cells, &prop);
+
+		pr_debug("cap_mem_regions[%d]: base=%pa, size=%pa\n",
+			 i, &rgn[i].base, &rgn[i].size);
+	}
+
+	memblock_cap_memory_range(rgn[0].base, rgn[0].size);
+	for (i = 1; i < MAX_USABLE_RANGES && rgn[i].size; i++)
+		memblock_add(rgn[i].base, rgn[i].size);
+}
+
+#ifdef CONFIG_SERIAL_EARLYCON
+
+int __init early_init_dt_scan_chosen_stdout(void)
+{
+	int offset;
+	const char *p, *q, *options = NULL;
+	int l;
+	const struct earlycon_id *match;
+	const void *fdt = initial_boot_params;
+	int ret;
+
+	offset = fdt_path_offset(fdt, "/chosen");
+	if (offset < 0)
+		offset = fdt_path_offset(fdt, "/chosen@0");
+	if (offset < 0)
+		return -ENOENT;
+
+	p = fdt_getprop(fdt, offset, "stdout-path", &l);
+	if (!p)
+		p = fdt_getprop(fdt, offset, "linux,stdout-path", &l);
+	if (!p || !l)
+		return -ENOENT;
+
+	q = strchrnul(p, ':');
+	if (*q != '\0')
+		options = q + 1;
+	l = q - p;
+
+	/* Get the node specified by stdout-path */
+	offset = fdt_path_offset_namelen(fdt, p, l);
+	if (offset < 0) {
+		pr_warn("earlycon: stdout-path %.*s not found\n", l, p);
+		return 0;
+	}
+
+	for (match = __earlycon_table; match < __earlycon_table_end; match++) {
+		if (!match->compatible[0])
+			continue;
+
+		if (fdt_node_check_compatible(fdt, offset, match->compatible))
+			continue;
+
+		ret = of_setup_earlycon(match, offset, options);
+		if (!ret || ret == -EALREADY)
+			return 0;
+	}
+	return -ENODEV;
+}
+#endif
+
+/*
+ * early_init_dt_scan_root - fetch the top level address and size cells
+ */
+int __init early_init_dt_scan_root(void)
+{
+	const __be32 *prop;
+	const void *fdt = initial_boot_params;
+	int node = fdt_path_offset(fdt, "/");
+
+	if (node < 0)
+		return -ENODEV;
+
+	dt_root_size_cells = OF_ROOT_NODE_SIZE_CELLS_DEFAULT;
+	dt_root_addr_cells = OF_ROOT_NODE_ADDR_CELLS_DEFAULT;
+
+	prop = of_get_flat_dt_prop(node, "#size-cells", NULL);
+	if (prop)
+		dt_root_size_cells = be32_to_cpup(prop);
+	pr_debug("dt_root_size_cells = %x\n", dt_root_size_cells);
+
+	prop = of_get_flat_dt_prop(node, "#address-cells", NULL);
+	if (prop)
+		dt_root_addr_cells = be32_to_cpup(prop);
+	pr_debug("dt_root_addr_cells = %x\n", dt_root_addr_cells);
+
+	return 0;
+}
+
+u64 __init dt_mem_next_cell(int s, const __be32 **cellp)
+{
+	const __be32 *p = *cellp;
+
+	*cellp = p + s;
+	return of_read_number(p, s);
+}
+
+/*
+ * early_init_dt_scan_memory - Look for and parse memory nodes
+ */
+int __init early_init_dt_scan_memory(void)
+{
+	int node, found_memory = 0;
+	const void *fdt = initial_boot_params;
+
+	fdt_for_each_subnode(node, fdt, 0) {
+		const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+		const __be32 *reg, *endp;
+		int l;
+		bool hotpluggable;
+
+		/* We are scanning "memory" nodes only */
+		if (type == NULL || strcmp(type, "memory") != 0)
+			continue;
+
+		if (!of_fdt_device_is_available(fdt, node))
+			continue;
+
+		reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
+		if (reg == NULL)
+			reg = of_get_flat_dt_prop(node, "reg", &l);
+		if (reg == NULL)
+			continue;
+
+		endp = reg + (l / sizeof(__be32));
+		hotpluggable = of_get_flat_dt_prop(node, "hotpluggable", NULL);
+
+		pr_debug("memory scan node %s, reg size %d,\n",
+			 fdt_get_name(fdt, node, NULL), l);
+
+		while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
+			u64 base, size;
+
+			base = dt_mem_next_cell(dt_root_addr_cells, &reg);
+			size = dt_mem_next_cell(dt_root_size_cells, &reg);
+
+			if (size == 0)
+				continue;
+			pr_debug(" - %llx, %llx\n", base, size);
+
+			early_init_dt_add_memory_arch(base, size);
+
+			found_memory = 1;
+
+			if (!hotpluggable)
+				continue;
+
+			if (memblock_mark_hotplug(base, size))
+				pr_warn("failed to mark hotplug range 0x%llx - 0x%llx\n",
+					base, base + size);
+		}
+	}
+	return found_memory;
+}
+
+int __init early_init_dt_scan_chosen(char *cmdline)
+{
+	int l, node;
+	const char *p;
+	const void *rng_seed;
+	const void *fdt = initial_boot_params;
+
+	node = fdt_path_offset(fdt, "/chosen");
+	if (node < 0)
+		node = fdt_path_offset(fdt, "/chosen@0");
+	if (node < 0)
+		/* Handle the cmdline config options even if no /chosen node */
+		goto handle_cmdline;
+
+	chosen_node_offset = node;
+
+	early_init_dt_check_for_initrd(node);
+	early_init_dt_check_for_elfcorehdr(node);
+
+	rng_seed = of_get_flat_dt_prop(node, "rng-seed", &l);
+	if (rng_seed && l > 0) {
+		add_bootloader_randomness(rng_seed, l);
+
+		/* try to clear seed so it won't be found. */
+		fdt_nop_property(initial_boot_params, node, "rng-seed");
+
+		/* update CRC check value */
+		of_fdt_crc32 = crc32_be(~0, initial_boot_params,
+				fdt_totalsize(initial_boot_params));
+	}
+
+	/* Retrieve command line */
+	p = of_get_flat_dt_prop(node, "bootargs", &l);
+	if (p != NULL && l > 0)
+		strscpy(cmdline, p, min(l, COMMAND_LINE_SIZE));
+
+handle_cmdline:
+	/*
+	 * CONFIG_CMDLINE is meant to be a default in case nothing else
+	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE
+	 * is set in which case we override whatever was found earlier.
+	 */
+#ifdef CONFIG_CMDLINE
+#if defined(CONFIG_CMDLINE_EXTEND)
+	strlcat(cmdline, " ", COMMAND_LINE_SIZE);
+	strlcat(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#elif defined(CONFIG_CMDLINE_FORCE)
+	strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#else
+	/* No arguments from boot loader, use kernel's  cmdl*/
+	if (!((char *)cmdline)[0])
+		strscpy(cmdline, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
+#endif
+#endif /* CONFIG_CMDLINE */
+
+	pr_debug("Command line is: %s\n", (char *)cmdline);
+
+	return 0;
+}
+
+#ifndef MIN_MEMBLOCK_ADDR
+#define MIN_MEMBLOCK_ADDR	__pa(PAGE_OFFSET)
+#endif
+#ifndef MAX_MEMBLOCK_ADDR
+#define MAX_MEMBLOCK_ADDR	((phys_addr_t)~0)
+#endif
+
+void __init __weak early_init_dt_add_memory_arch(u64 base, u64 size)
+{
+	const u64 phys_offset = MIN_MEMBLOCK_ADDR;
+
+	if (size < PAGE_SIZE - (base & ~PAGE_MASK)) {
+		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
+			base, base + size);
+		return;
+	}
+
+	if (!PAGE_ALIGNED(base)) {
+		size -= PAGE_SIZE - (base & ~PAGE_MASK);
+		base = PAGE_ALIGN(base);
+	}
+	size &= PAGE_MASK;
+
+	if (base > MAX_MEMBLOCK_ADDR) {
+		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
+			base, base + size);
+		return;
+	}
+
+	if (base + size - 1 > MAX_MEMBLOCK_ADDR) {
+		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
+			((u64)MAX_MEMBLOCK_ADDR) + 1, base + size);
+		size = MAX_MEMBLOCK_ADDR - base + 1;
+	}
+
+	if (base + size < phys_offset) {
+		pr_warn("Ignoring memory block 0x%llx - 0x%llx\n",
+			base, base + size);
+		return;
+	}
+	if (base < phys_offset) {
+		pr_warn("Ignoring memory range 0x%llx - 0x%llx\n",
+			base, phys_offset);
+		size -= phys_offset - base;
+		base = phys_offset;
+	}
+	memblock_add(base, size);
+}
+
+static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
+{
+	void *ptr = memblock_alloc(size, align);
+
+	if (!ptr)
+		panic("%s: Failed to allocate %llu bytes align=0x%llx\n",
+		      __func__, size, align);
+
+	return ptr;
+}
+
+bool __init early_init_dt_verify(void *params)
+{
+	if (!params)
+		return false;
+
+	/* check device tree validity */
+	if (fdt_check_header(params))
+		return false;
+
+	/* Setup flat device-tree pointer */
+	initial_boot_params = params;
+	of_fdt_crc32 = crc32_be(~0, initial_boot_params,
+				fdt_totalsize(initial_boot_params));
+	return true;
+}
+
+
+void __init early_init_dt_scan_nodes(void)
+{
+	int rc;
+
+	/* Initialize {size,address}-cells info */
+	early_init_dt_scan_root();
+
+	/* Retrieve various information from the /chosen node */
+	rc = early_init_dt_scan_chosen(boot_command_line);
+	if (rc)
+		pr_warn("No chosen node found, continuing without\n");
+
+	/* Setup memory, calling early_init_dt_add_memory_arch */
+	early_init_dt_scan_memory();
+
+	/* Handle linux,usable-memory-range property */
+	early_init_dt_check_for_usable_mem_range();
+}
+
+bool __init early_init_dt_scan(void *params)
+{
+	bool status;
+
+	status = early_init_dt_verify(params);
+	if (!status)
+		return false;
+
+	early_init_dt_scan_nodes();
+	return true;
+}
+
+/**
+ * unflatten_device_tree - create tree of device_nodes from flat blob
+ *
+ * unflattens the device-tree passed by the firmware, creating the
+ * tree of struct device_node. It also fills the "name" and "type"
+ * pointers of the nodes so the normal device-tree walking functions
+ * can be used.
+ */
+void __init unflatten_device_tree(void)
+{
+	__unflatten_device_tree(initial_boot_params, NULL, &of_root,
+				early_init_dt_alloc_memory_arch, false);
+
+	/* Get pointer to "/chosen" and "/aliases" nodes for use everywhere */
+	of_alias_scan(early_init_dt_alloc_memory_arch);
+
+	unittest_unflatten_overlay_base();
+}
+
+/**
+ * unflatten_and_copy_device_tree - copy and create tree of device_nodes from flat blob
+ *
+ * Copies and unflattens the device-tree passed by the firmware, creating the
+ * tree of struct device_node. It also fills the "name" and "type"
+ * pointers of the nodes so the normal device-tree walking functions
+ * can be used. This should only be used when the FDT memory has not been
+ * reserved such is the case when the FDT is built-in to the kernel init
+ * section. If the FDT memory is reserved already then unflatten_device_tree
+ * should be used instead.
+ */
+void __init unflatten_and_copy_device_tree(void)
+{
+	int size;
+	void *dt;
+
+	if (!initial_boot_params) {
+		pr_warn("No valid device tree found, continuing without\n");
+		return;
+	}
+
+	size = fdt_totalsize(initial_boot_params);
+	dt = early_init_dt_alloc_memory_arch(size,
+					     roundup_pow_of_two(FDT_V17_SIZE));
+
+	if (dt) {
+		memcpy(dt, initial_boot_params, size);
+		initial_boot_params = dt;
+	}
+	unflatten_device_tree();
+}
+
+#ifdef CONFIG_SYSFS
+static ssize_t of_fdt_raw_read(struct file *filp, struct kobject *kobj,
+			       struct bin_attribute *bin_attr,
+			       char *buf, loff_t off, size_t count)
+{
+	memcpy(buf, initial_boot_params + off, count);
+	return count;
+}
+
+static int __init of_fdt_raw_init(void)
+{
+	static struct bin_attribute of_fdt_raw_attr =
+		__BIN_ATTR(fdt, S_IRUSR, of_fdt_raw_read, NULL, 0);
+
+	if (!initial_boot_params)
+		return 0;
+
+	if (of_fdt_crc32 != crc32_be(~0, initial_boot_params,
+				     fdt_totalsize(initial_boot_params))) {
+		pr_warn("not creating '/sys/firmware/fdt': CRC check failed\n");
+		return 0;
+	}
+	of_fdt_raw_attr.size = fdt_totalsize(initial_boot_params);
+	return sysfs_create_bin_file(firmware_kobj, &of_fdt_raw_attr);
+}
+late_initcall(of_fdt_raw_init);
+#endif
+
+#endif /* CONFIG_OF_EARLY_FLATTREE */