of/fdt: Convert FDT functions to use libfdt

The kernel FDT functions predate libfdt and are much more limited in
functionality. Also, the kernel functions and libfdt functions are
not compatible with each other because they have different definitions
of node offsets. To avoid this incompatibility and in preparation to
add more FDT parsing functions which will need libfdt, let's first
convert the existing code to use libfdt.

The FDT unflattening, top-level FDT scanning, and property retrieval
functions are converted to use libfdt. The scanning code should be
re-worked to be more efficient and understandable by using libfdt to
find nodes directly by path or compatible strings.

Signed-off-by: Rob Herring <robh@kernel.org>
Tested-by: Michal Simek <michal.simek@xilinx.com>
Tested-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Stephen Chivers <schivers@csc.com>
(cherry picked from commit e6a6928c3ea1d0195ed75a091e345696b916c09b)
Signed-off-by: Mark Brown <broonie@linaro.org>

Conflicts:
	drivers/of/fdt.c

4 files changed, 70 insertions, 165 deletions

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index bdc7f9a0c500..a7bb5da6a96b 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -27,6 +27,7 @@ config OF_SELFTEST
 config OF_FLATTREE
 	bool
 	select DTC
+	select LIBFDT
 
 config OF_EARLY_FLATTREE
 	bool
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 8098b4dd357f..2aaa7b90fc14 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -12,3 +12,5 @@ obj-$(CONFIG_OF_PCI)	+= of_pci.o
 obj-$(CONFIG_OF_PCI_IRQ)  += of_pci_irq.o
 obj-$(CONFIG_OF_MTD)	+= of_mtd.o
 obj-$(CONFIG_OF_RESERVED_MEM) += of_reserved_mem.o
+
+CFLAGS_fdt.o = -I$(src)/../../scripts/dtc/libfdt
diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 39ac2961737b..10c08e82054b 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -20,6 +20,7 @@
 #include <linux/errno.h>
 #include <linux/slab.h>
 #include <linux/memblock.h>
+#include <linux/libfdt.h>
 
 #include <asm/setup.h>  /* for COMMAND_LINE_SIZE */
 #ifdef CONFIG_PPC
@@ -28,54 +29,6 @@
 
 #include <asm/page.h>
 
-char *of_fdt_get_string(struct boot_param_header *blob, u32 offset)
-{
-	return ((char *)blob) +
-		be32_to_cpu(blob->off_dt_strings) + offset;
-}
-
-/**
- * of_fdt_get_property - Given a node in the given flat blob, return
- * the property ptr
- */
-void *of_fdt_get_property(struct boot_param_header *blob,
-		       unsigned long node, const char *name,
-		       int *size)
-{
-	unsigned long p = node;
-
-	do {
-		u32 tag = be32_to_cpup((__be32 *)p);
-		u32 sz, noff;
-		const char *nstr;
-
-		p += 4;
-		if (tag == OF_DT_NOP)
-			continue;
-		if (tag != OF_DT_PROP)
-			return NULL;
-
-		sz = be32_to_cpup((__be32 *)p);
-		noff = be32_to_cpup((__be32 *)(p + 4));
-		p += 8;
-		if (be32_to_cpu(blob->version) < 0x10)
-			p = ALIGN(p, sz >= 8 ? 8 : 4);
-
-		nstr = of_fdt_get_string(blob, noff);
-		if (nstr == NULL) {
-			pr_warning("Can't find property index name !\n");
-			return NULL;
-		}
-		if (strcmp(name, nstr) == 0) {
-			if (size)
-				*size = sz;
-			return (void *)p;
-		}
-		p += sz;
-		p = ALIGN(p, 4);
-	} while (1);
-}
-
 /**
  * of_fdt_is_compatible - Return true if given node from the given blob has
  * compat in its compatible list
@@ -93,7 +46,7 @@ int of_fdt_is_compatible(struct boot_param_header *blob,
 	int cplen;
 	unsigned long l, score = 0;
 
-	cp = of_fdt_get_property(blob, node, "compatible", &cplen);
+	cp = fdt_getprop(blob, node, "compatible", &cplen);
 	if (cp == NULL)
 		return 0;
 	while (cplen > 0) {
@@ -129,12 +82,12 @@ int of_fdt_match(struct boot_param_header *blob, unsigned long node,
 	return score;
 }
 
-static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
+static void *unflatten_dt_alloc(void **mem, unsigned long size,
 				       unsigned long align)
 {
 	void *res;
 
-	*mem = ALIGN(*mem, align);
+	*mem = PTR_ALIGN(*mem, align);
 	res = (void *)*mem;
 	*mem += size;
 
@@ -150,30 +103,29 @@ static void *unflatten_dt_alloc(unsigned long *mem, unsigned long size,
  * @allnextpp: pointer to ->allnext from last allocated device_node
  * @fpsize: Size of the node path up at the current depth.
  */
-static unsigned long unflatten_dt_node(struct boot_param_header *blob,
-				unsigned long mem,
-				unsigned long *p,
+static void * unflatten_dt_node(struct boot_param_header *blob,
+				void *mem,
+				int *poffset,
 				struct device_node *dad,
 				struct device_node ***allnextpp,
 				unsigned long fpsize)
 {
+	const __be32 *p;
 	struct device_node *np;
 	struct property *pp, **prev_pp = NULL;
-	char *pathp;
-	u32 tag;
+	const char *pathp;
 	unsigned int l, allocl;
+	static int depth = 0;
+	int old_depth;
+	int offset;
 	int has_name = 0;
 	int new_format = 0;
 
-	tag = be32_to_cpup((__be32 *)(*p));
-	if (tag != OF_DT_BEGIN_NODE) {
-		pr_err("Weird tag at start of node: %x\n", tag);
+	pathp = fdt_get_name(blob, *poffset, &l);
+	if (!pathp)
 		return mem;
-	}
-	*p += 4;
-	pathp = (char *)*p;
-	l = allocl = strlen(pathp) + 1;
-	*p = ALIGN(*p + l, 4);
+
+	allocl = l++;
 
 	/* version 0x10 has a more compact unit name here instead of the full
 	 * path. we accumulate the full path size using "fpsize", we'll rebuild
@@ -191,7 +143,7 @@ static unsigned long unflatten_dt_node(struct boot_param_header *blob,
 			fpsize = 1;
 			allocl = 2;
 			l = 1;
-			*pathp = '\0';
+			pathp = "";
 		} else {
 			/* account for '/' and path size minus terminal 0
 			 * already in 'l'
@@ -239,32 +191,23 @@ static unsigned long unflatten_dt_node(struct boot_param_header *blob,
 		kref_init(&np->kref);
 	}
 	/* process properties */
-	while (1) {
-		u32 sz, noff;
-		char *pname;
-
-		tag = be32_to_cpup((__be32 *)(*p));
-		if (tag == OF_DT_NOP) {
-			*p += 4;
-			continue;
-		}
-		if (tag != OF_DT_PROP)
+	for (offset = fdt_first_property_offset(blob, *poffset);
+	     (offset >= 0);
+	     (offset = fdt_next_property_offset(blob, offset))) {
+		const char *pname;
+		u32 sz;
+
+		if (!(p = fdt_getprop_by_offset(blob, offset, &pname, &sz))) {
+			offset = -FDT_ERR_INTERNAL;
 			break;
-		*p += 4;
-		sz = be32_to_cpup((__be32 *)(*p));
-		noff = be32_to_cpup((__be32 *)((*p) + 4));
-		*p += 8;
-		if (be32_to_cpu(blob->version) < 0x10)
-			*p = ALIGN(*p, sz >= 8 ? 8 : 4);
-
-		pname = of_fdt_get_string(blob, noff);
+		}
+
 		if (pname == NULL) {
 			pr_info("Can't find property name in list !\n");
 			break;
 		}
 		if (strcmp(pname, "name") == 0)
 			has_name = 1;
-		l = strlen(pname) + 1;
 		pp = unflatten_dt_alloc(&mem, sizeof(struct property),
 					__alignof__(struct property));
 		if (allnextpp) {
@@ -276,26 +219,25 @@ static unsigned long unflatten_dt_node(struct boot_param_header *blob,
 			if ((strcmp(pname, "phandle") == 0) ||
 			    (strcmp(pname, "linux,phandle") == 0)) {
 				if (np->phandle == 0)
-					np->phandle = be32_to_cpup((__be32*)*p);
+					np->phandle = be32_to_cpup(p);
 			}
 			/* And we process the "ibm,phandle" property
 			 * used in pSeries dynamic device tree
 			 * stuff */
 			if (strcmp(pname, "ibm,phandle") == 0)
-				np->phandle = be32_to_cpup((__be32 *)*p);
-			pp->name = pname;
+				np->phandle = be32_to_cpup(p);
+			pp->name = (char *)pname;
 			pp->length = sz;
-			pp->value = (void *)*p;
+			pp->value = (__be32 *)p;
 			*prev_pp = pp;
 			prev_pp = &pp->next;
 		}
-		*p = ALIGN((*p) + sz, 4);
 	}
 	/* with version 0x10 we may not have the name property, recreate
 	 * it here from the unit name if absent
 	 */
 	if (!has_name) {
-		char *p1 = pathp, *ps = pathp, *pa = NULL;
+		const char *p1 = pathp, *ps = pathp, *pa = NULL;
 		int sz;
 
 		while (*p1) {
@@ -332,19 +274,18 @@ static unsigned long unflatten_dt_node(struct boot_param_header *blob,
 		if (!np->type)
 			np->type = "<NULL>";
 	}
-	while (tag == OF_DT_BEGIN_NODE || tag == OF_DT_NOP) {
-		if (tag == OF_DT_NOP)
-			*p += 4;
-		else
-			mem = unflatten_dt_node(blob, mem, p, np, allnextpp,
-						fpsize);
-		tag = be32_to_cpup((__be32 *)(*p));
-	}
-	if (tag != OF_DT_END_NODE) {
-		pr_err("Weird tag at end of node: %x\n", tag);
-		return mem;
-	}
-	*p += 4;
+
+	old_depth = depth;
+	*poffset = fdt_next_node(blob, *poffset, &depth);
+	if (depth < 0)
+		depth = 0;
+	while (*poffset > 0 && depth > old_depth)
+		mem = unflatten_dt_node(blob, mem, poffset, np, allnextpp,
+					fpsize);
+
+	if (*poffset < 0 && *poffset != -FDT_ERR_NOTFOUND)
+		pr_err("unflatten: error %d processing FDT\n", *poffset);
+
 	return mem;
 }
 
@@ -364,7 +305,9 @@ static void __unflatten_device_tree(struct boot_param_header *blob,
 			     struct device_node **mynodes,
 			     void * (*dt_alloc)(u64 size, u64 align))
 {
-	unsigned long start, mem, size;
+	unsigned long size;
+	int start;
+	void *mem;
 	struct device_node **allnextp = mynodes;
 
 	pr_debug(" -> unflatten_device_tree()\n");
@@ -385,28 +328,23 @@ static void __unflatten_device_tree(struct boot_param_header *blob,
 	}
 
 	/* First pass, scan for size */
-	start = ((unsigned long)blob) +
-		be32_to_cpu(blob->off_dt_struct);
-	size = unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
-	size = (size | 3) + 1;
+	start = 0;
+	size = (unsigned long)unflatten_dt_node(blob, 0, &start, NULL, NULL, 0);
+	size = ALIGN(size, 4);
 
 	pr_debug("  size is %lx, allocating...\n", size);
 
 	/* Allocate memory for the expanded device tree */
-	mem = (unsigned long)
-		dt_alloc(size + 4, __alignof__(struct device_node));
+	mem = dt_alloc(size + 4, __alignof__(struct device_node));
 
 	((__be32 *)mem)[size / 4] = cpu_to_be32(0xdeadbeef);
 
-	pr_debug("  unflattening %lx...\n", mem);
+	pr_debug("  unflattening %p...\n", mem);
 
 	/* Second pass, do actual unflattening */
-	start = ((unsigned long)blob) +
-		be32_to_cpu(blob->off_dt_struct);
+	start = 0;
 	unflatten_dt_node(blob, mem, &start, NULL, &allnextp, 0);
-	if (be32_to_cpup((__be32 *)start) != OF_DT_END)
-		pr_warning("Weird tag at end of tree: %08x\n", *((u32 *)start));
-	if (be32_to_cpu(((__be32 *)mem)[size / 4]) != 0xdeadbeef)
+	if (be32_to_cpup(mem + size) != 0xdeadbeef)
 		pr_warning("End of tree marker overwritten: %08x\n",
 			   be32_to_cpu(((__be32 *)mem)[size / 4]));
 	*allnextp = NULL;
@@ -581,47 +519,19 @@ int __init of_scan_flat_dt(int (*it)(unsigned long node,
 				     void *data),
 			   void *data)
 {
-	unsigned long p = ((unsigned long)initial_boot_params) +
-		be32_to_cpu(initial_boot_params->off_dt_struct);
-	int rc = 0;
-	int depth = -1;
-
-	do {
-		u32 tag = be32_to_cpup((__be32 *)p);
-		const char *pathp;
-
-		p += 4;
-		if (tag == OF_DT_END_NODE) {
-			depth--;
-			continue;
-		}
-		if (tag == OF_DT_NOP)
-			continue;
-		if (tag == OF_DT_END)
-			break;
-		if (tag == OF_DT_PROP) {
-			u32 sz = be32_to_cpup((__be32 *)p);
-			p += 8;
-			if (be32_to_cpu(initial_boot_params->version) < 0x10)
-				p = ALIGN(p, sz >= 8 ? 8 : 4);
-			p += sz;
-			p = ALIGN(p, 4);
-			continue;
-		}
-		if (tag != OF_DT_BEGIN_NODE) {
-			pr_err("Invalid tag %x in flat device tree!\n", tag);
-			return -EINVAL;
-		}
-		depth++;
-		pathp = (char *)p;
-		p = ALIGN(p + strlen(pathp) + 1, 4);
+	const void *blob = initial_boot_params;
+	const char *pathp;
+	int offset, rc = 0, depth = -1;
+
+        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);
 		if (*pathp == '/')
 			pathp = kbasename(pathp);
-		rc = it(p, pathp, depth, data);
-		if (rc != 0)
-			break;
-	} while (1);
-
+		rc = it(offset, pathp, depth, data);
+	}
 	return rc;
 }
 
@@ -630,14 +540,7 @@ int __init of_scan_flat_dt(int (*it)(unsigned long node,
  */
 unsigned long __init of_get_flat_dt_root(void)
 {
-	unsigned long p = ((unsigned long)initial_boot_params) +
-		be32_to_cpu(initial_boot_params->off_dt_struct);
-
-	while (be32_to_cpup((__be32 *)p) == OF_DT_NOP)
-		p += 4;
-	BUG_ON(be32_to_cpup((__be32 *)p) != OF_DT_BEGIN_NODE);
-	p += 4;
-	return ALIGN(p + strlen((char *)p) + 1, 4);
+	return 0;
 }
 
 /**
@@ -649,7 +552,7 @@ unsigned long __init of_get_flat_dt_root(void)
 const void *__init of_get_flat_dt_prop(unsigned long node, const char *name,
 				       int *size)
 {
-	return of_fdt_get_property(initial_boot_params, node, name, size);
+	return fdt_getprop(initial_boot_params, node, name, size);
 }
 
 /**
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 461b5114d9af..c9722fdf39c5 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -81,7 +81,6 @@ extern int __initdata dt_root_size_cells;
 extern struct boot_param_header *initial_boot_params;
 
 /* For scanning the flat device-tree at boot time */
-extern char *find_flat_dt_string(u32 offset);
 extern int of_scan_flat_dt(int (*it)(unsigned long node, const char *uname,
 				     int depth, void *data),
 			   void *data);