Merge tag 'devicetree-for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux into next

Pull DeviceTree updates from Rob Herring:
 - Another round of clean-up of FDT related code in architecture code.
   This removes knowledge of internal FDT details from most
   architectures except powerpc.
 - Conversion of kernel's custom FDT parsing code to use libfdt.
 - DT based initialization for generic serial earlycon.  The
   introduction of generic serial earlycon support went in through the
   tty tree.
 - Improve the platform device naming for DT probed devices to ensure
   unique naming and use parent names instead of a global index.
 - Fix a race condition in of_update_property.
 - Unify the various linker section OF match tables and fix several
   function prototype errors.
 - Update platform_get_irq_byname to work in deferred probe cases.
 - 2 binding doc updates

* tag 'devicetree-for-3.16' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (58 commits)
  of: handle NULL node in next_child iterators
  of/irq: provide more wrappers for !CONFIG_OF
  devicetree: bindings: Document micrel vendor prefix
  dt: bindings: dwc2: fix required value for the phy-names property
  of_pci_irq: kill useless variable in of_irq_parse_pci()
  of/irq: do irq resolution in platform_get_irq_byname()
  of: Add a testcase for of_find_node_by_path()
  of: Make of_find_node_by_path() handle /aliases
  of: Create unlocked version of for_each_child_of_node()
  lib: add glibc style strchrnul() variant
  of: Handle memory@0 node on PPC32 only
  pci/of: Remove dead code
  of: fix race between search and remove in of_update_property()
  of: Use NULL for pointers
  of: Stop naming platform_device using dcr address
  of: Ensure unique names without sacrificing determinism
  tty/serial: pl011: add DT based earlycon support
  of/fdt: add FDT serial scanning for earlycon
  of/fdt: add FDT address translation support
  serial: earlycon: add DT support
  ...

37 files changed, 134 insertions, 301 deletions

diff --git a/arch/arc/include/asm/sections.h b/arch/arc/include/asm/sections.h
index 764f1e3ba752..09db952e14bd 100644
--- a/arch/arc/include/asm/sections.h
+++ b/arch/arc/include/asm/sections.h
@@ -12,6 +12,5 @@
 #include <asm-generic/sections.h>
 
 extern char __arc_dccm_base[];
-extern char __dtb_start[];
 
 #endif
diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c
index b6dc4e21fd32..0b3ef4025d89 100644
--- a/arch/arc/kernel/devtree.c
+++ b/arch/arc/kernel/devtree.c
@@ -42,7 +42,7 @@ const struct machine_desc * __init setup_machine_fdt(void *dt)
 	const struct machine_desc *mdesc;
 	unsigned long dt_root;
 	void *clk;
-	unsigned long len;
+	int len;
 
 	if (!early_init_dt_scan(dt))
 		return NULL;
diff --git a/arch/arm/include/asm/prom.h b/arch/arm/include/asm/prom.h
index b681575ad3de..cd94ef2ef283 100644
--- a/arch/arm/include/asm/prom.h
+++ b/arch/arm/include/asm/prom.h
@@ -14,7 +14,6 @@
 #ifdef CONFIG_OF
 
 extern const struct machine_desc *setup_machine_fdt(unsigned int dt_phys);
-extern void arm_dt_memblock_reserve(void);
 extern void __init arm_dt_init_cpu_maps(void);
 
 #else /* CONFIG_OF */
@@ -24,7 +23,6 @@ static inline const struct machine_desc *setup_machine_fdt(unsigned int dt_phys)
 	return NULL;
 }
 
-static inline void arm_dt_memblock_reserve(void) { }
 static inline void arm_dt_init_cpu_maps(void) { }
 
 #endif /* CONFIG_OF */
diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index c7419a585ddc..ea9ce92a4b52 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c
@@ -32,51 +32,22 @@ void __init early_init_dt_add_memory_arch(u64 base, u64 size)
 	arm_add_memory(base, size);
 }
 
-void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
-{
-	return memblock_virt_alloc(size, align);
-}
-
-void __init arm_dt_memblock_reserve(void)
-{
-	u64 *reserve_map, base, size;
-
-	if (!initial_boot_params)
-		return;
-
-	/* Reserve the dtb region */
-	memblock_reserve(virt_to_phys(initial_boot_params),
-			 be32_to_cpu(initial_boot_params->totalsize));
+#ifdef CONFIG_SMP
+extern struct of_cpu_method __cpu_method_of_table[];
 
-	/*
-	 * Process the reserve map.  This will probably overlap the initrd
-	 * and dtb locations which are already reserved, but overlaping
-	 * doesn't hurt anything
-	 */
-	reserve_map = ((void*)initial_boot_params) +
-			be32_to_cpu(initial_boot_params->off_mem_rsvmap);
-	while (1) {
-		base = be64_to_cpup(reserve_map++);
-		size = be64_to_cpup(reserve_map++);
-		if (!size)
-			break;
-		memblock_reserve(base, size);
-	}
-}
+static const struct of_cpu_method __cpu_method_of_table_sentinel
+	__used __section(__cpu_method_of_table_end);
 
-#ifdef CONFIG_SMP
-extern struct of_cpu_method __cpu_method_of_table_begin[];
-extern struct of_cpu_method __cpu_method_of_table_end[];
 
 static int __init set_smp_ops_by_method(struct device_node *node)
 {
 	const char *method;
-	struct of_cpu_method *m = __cpu_method_of_table_begin;
+	struct of_cpu_method *m = __cpu_method_of_table;
 
 	if (of_property_read_string(node, "enable-method", &method))
 		return 0;
 
-	for (; m < __cpu_method_of_table_end; m++)
+	for (; m->method; m++)
 		if (!strcmp(m->method, method)) {
 			smp_set_ops(m->ops);
 			return 1;
@@ -252,7 +223,7 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
 
 	if (!mdesc) {
 		const char *prop;
-		long size;
+		int size;
 		unsigned long dt_root;
 
 		early_print("\nError: unrecognized/unsupported "
diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
index bc43e22693b7..a56ce45a3f90 100644
--- a/arch/arm/mach-exynos/exynos.c
+++ b/arch/arm/mach-exynos/exynos.c
@@ -202,7 +202,7 @@ static int __init exynos_fdt_map_chipid(unsigned long node, const char *uname,
 {
 	struct map_desc iodesc;
 	__be32 *reg;
-	unsigned long len;
+	int len;
 
 	if (!of_flat_dt_is_compatible(node, "samsung,exynos4210-chipid") &&
 		!of_flat_dt_is_compatible(node, "samsung,exynos5440-clock"))
diff --git a/arch/arm/mach-imx/clk-imx35.c b/arch/arm/mach-imx/clk-imx35.c
index a4d5e425cd82..71c86a2f856d 100644
--- a/arch/arm/mach-imx/clk-imx35.c
+++ b/arch/arm/mach-imx/clk-imx35.c
@@ -289,14 +289,12 @@ int __init mx35_clocks_init(void)
 	return 0;
 }
 
-static int __init mx35_clocks_init_dt(struct device_node *ccm_node)
+static void __init mx35_clocks_init_dt(struct device_node *ccm_node)
 {
 	clk_data.clks = clk;
 	clk_data.clk_num = ARRAY_SIZE(clk);
 	of_clk_add_provider(ccm_node, of_clk_src_onecell_get, &clk_data);
 
 	mx35_clocks_init();
-
-	return 0;
 }
 CLK_OF_DECLARE(imx35, "fsl,imx35-ccm", mx35_clocks_init_dt);
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 2a77ba8796ae..928d596d9ab4 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -317,7 +317,6 @@ void __init arm_memblock_init(struct meminfo *mi,
 #endif
 
 	arm_mm_memblock_reserve();
-	arm_dt_memblock_reserve();
 
 	/* reserve any platform specific memblock areas */
 	if (mdesc->reserve)
diff --git a/arch/arm/plat-samsung/s5p-dev-mfc.c b/arch/arm/plat-samsung/s5p-dev-mfc.c
index 98087b655df0..469b86260fe3 100644
--- a/arch/arm/plat-samsung/s5p-dev-mfc.c
+++ b/arch/arm/plat-samsung/s5p-dev-mfc.c
@@ -125,8 +125,8 @@ device_initcall(s5p_mfc_memory_init);
 int __init s5p_fdt_alloc_mfc_mem(unsigned long node, const char *uname,
 				int depth, void *data)
 {
-	__be32 *prop;
-	unsigned long len;
+	const __be32 *prop;
+	int len;
 	struct s5p_mfc_dt_meminfo mfc_mem;
 
 	if (!data)
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 51d5352e6ad5..091d428d64ac 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -126,8 +126,6 @@ static void arm64_memory_present(void)
 
 void __init arm64_memblock_init(void)
 {
-	u64 *reserve_map, base, size;
-
 	/* Register the kernel text, kernel data and initrd with memblock */
 	memblock_reserve(__pa(_text), _end - _text);
 #ifdef CONFIG_BLK_DEV_INITRD
@@ -142,25 +140,6 @@ void __init arm64_memblock_init(void)
 	memblock_reserve(__pa(swapper_pg_dir), SWAPPER_DIR_SIZE);
 	memblock_reserve(__pa(idmap_pg_dir), IDMAP_DIR_SIZE);
 
-	/* Reserve the dtb region */
-	memblock_reserve(virt_to_phys(initial_boot_params),
-			 be32_to_cpu(initial_boot_params->totalsize));
-
-	/*
-	 * Process the reserve map.  This will probably overlap the initrd
-	 * and dtb locations which are already reserved, but overlapping
-	 * doesn't hurt anything
-	 */
-	reserve_map = ((void*)initial_boot_params) +
-			be32_to_cpu(initial_boot_params->off_mem_rsvmap);
-	while (1) {
-		base = be64_to_cpup(reserve_map++);
-		size = be64_to_cpup(reserve_map++);
-		if (!size)
-			break;
-		memblock_reserve(base, size);
-	}
-
 	early_init_fdt_scan_reserved_mem();
 	dma_contiguous_reserve(0);
 
diff --git a/arch/c6x/kernel/setup.c b/arch/c6x/kernel/setup.c
index 731db4b9014d..757128868d43 100644
--- a/arch/c6x/kernel/setup.c
+++ b/arch/c6x/kernel/setup.c
@@ -265,8 +265,8 @@ int __init c6x_add_memory(phys_addr_t start, unsigned long size)
  */
 notrace void __init machine_init(unsigned long dt_ptr)
 {
-	struct boot_param_header *dtb = __va(dt_ptr);
-	struct boot_param_header *fdt = (struct boot_param_header *)_fdt_start;
+	const void *dtb = __va(dt_ptr);
+	const void *fdt = _fdt_start;
 
 	/* interrupts must be masked */
 	set_creg(IER, 2);
diff --git a/arch/metag/kernel/setup.c b/arch/metag/kernel/setup.c
index 129c7cdda1ce..31cf53d0eba2 100644
--- a/arch/metag/kernel/setup.c
+++ b/arch/metag/kernel/setup.c
@@ -105,10 +105,6 @@
 
 extern char _heap_start[];
 
-#ifdef CONFIG_METAG_BUILTIN_DTB
-extern u32 __dtb_start[];
-#endif
-
 #ifdef CONFIG_DA_CONSOLE
 /* Our early channel based console driver */
 extern struct console dash_console;
diff --git a/arch/microblaze/kernel/prom.c b/arch/microblaze/kernel/prom.c
index abdfb10e7eca..68f099960ebc 100644
--- a/arch/microblaze/kernel/prom.c
+++ b/arch/microblaze/kernel/prom.c
@@ -43,13 +43,13 @@
 #include <asm/pci-bridge.h>
 
 #ifdef CONFIG_EARLY_PRINTK
-static char *stdout;
+static const char *stdout;
 
 static int __init early_init_dt_scan_chosen_serial(unsigned long node,
 				const char *uname, int depth, void *data)
 {
-	unsigned long l;
-	char *p;
+	int l;
+	const char *p;
 
 	pr_debug("%s: depth: %d, uname: %s\n", __func__, depth, uname);
 
@@ -80,7 +80,7 @@ static int __init early_init_dt_scan_chosen_serial(unsigned long node,
 				(strncmp(p, "xlnx,opb-uartlite", 17) == 0) ||
 				(strncmp(p, "xlnx,axi-uartlite", 17) == 0) ||
 				(strncmp(p, "xlnx,mdm", 8) == 0)) {
-			unsigned int *addrp;
+			const unsigned int *addrp;
 
 			*(u32 *)data = UARTLITE;
 
@@ -114,34 +114,3 @@ void __init early_init_devtree(void *params)
 
 	pr_debug(" <- early_init_devtree()\n");
 }
-
-/*******
- *
- * New implementation of the OF "find" APIs, return a refcounted
- * object, call of_node_put() when done.  The device tree and list
- * are protected by a rw_lock.
- *
- * Note that property management will need some locking as well,
- * this isn't dealt with yet.
- *
- *******/
-
-#if defined(CONFIG_DEBUG_FS) && defined(DEBUG)
-static struct debugfs_blob_wrapper flat_dt_blob;
-
-static int __init export_flat_device_tree(void)
-{
-	struct dentry *d;
-
-	flat_dt_blob.data = initial_boot_params;
-	flat_dt_blob.size = initial_boot_params->totalsize;
-
-	d = debugfs_create_blob("flat-device-tree", S_IFREG | S_IRUSR,
-				of_debugfs_root, &flat_dt_blob);
-	if (!d)
-		return 1;
-
-	return 0;
-}
-device_initcall(export_flat_device_tree);
-#endif
diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c
index 331b837cec57..f1bec00d5a85 100644
--- a/arch/mips/cavium-octeon/setup.c
+++ b/arch/mips/cavium-octeon/setup.c
@@ -1053,36 +1053,26 @@ void prom_free_prom_memory(void)
 int octeon_prune_device_tree(void);
 
 extern const char __dtb_octeon_3xxx_begin;
-extern const char __dtb_octeon_3xxx_end;
 extern const char __dtb_octeon_68xx_begin;
-extern const char __dtb_octeon_68xx_end;
 void __init device_tree_init(void)
 {
-	int dt_size;
-	struct boot_param_header *fdt;
+	const void *fdt;
 	bool do_prune;
 
 	if (octeon_bootinfo->minor_version >= 3 && octeon_bootinfo->fdt_addr) {
 		fdt = phys_to_virt(octeon_bootinfo->fdt_addr);
 		if (fdt_check_header(fdt))
 			panic("Corrupt Device Tree passed to kernel.");
-		dt_size = be32_to_cpu(fdt->totalsize);
 		do_prune = false;
 	} else if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
-		fdt = (struct boot_param_header *)&__dtb_octeon_68xx_begin;
-		dt_size = &__dtb_octeon_68xx_end - &__dtb_octeon_68xx_begin;
+		fdt = &__dtb_octeon_68xx_begin;
 		do_prune = true;
 	} else {
-		fdt = (struct boot_param_header *)&__dtb_octeon_3xxx_begin;
-		dt_size = &__dtb_octeon_3xxx_end - &__dtb_octeon_3xxx_begin;
+		fdt = &__dtb_octeon_3xxx_begin;
 		do_prune = true;
 	}
 
-	/* Copy the default tree from init memory. */
-	initial_boot_params = early_init_dt_alloc_memory_arch(dt_size, 8);
-	if (initial_boot_params == NULL)
-		panic("Could not allocate initial_boot_params");
-	memcpy(initial_boot_params, fdt, dt_size);
+	initial_boot_params = (void *)fdt;
 
 	if (do_prune) {
 		octeon_prune_device_tree();
@@ -1090,7 +1080,7 @@ void __init device_tree_init(void)
 	} else {
 		pr_info("Using passed Device Tree.\n");
 	}
-	unflatten_device_tree();
+	unflatten_and_copy_device_tree();
 }
 
 static int __initdata disable_octeon_edac_p;
diff --git a/arch/mips/include/asm/mips-boards/generic.h b/arch/mips/include/asm/mips-boards/generic.h
index 48616816bcbc..c904c24550f6 100644
--- a/arch/mips/include/asm/mips-boards/generic.h
+++ b/arch/mips/include/asm/mips-boards/generic.h
@@ -67,10 +67,6 @@
 
 extern int mips_revision_sconid;
 
-#ifdef CONFIG_OF
-extern struct boot_param_header __dtb_start;
-#endif
-
 #ifdef CONFIG_PCI
 extern void mips_pcibios_init(void);
 #else
diff --git a/arch/mips/include/asm/prom.h b/arch/mips/include/asm/prom.h
index ccd2b75f152c..a9494c0141fb 100644
--- a/arch/mips/include/asm/prom.h
+++ b/arch/mips/include/asm/prom.h
@@ -21,13 +21,13 @@ extern void device_tree_init(void);
 
 struct boot_param_header;
 
-extern void __dt_setup_arch(struct boot_param_header *bph);
+extern void __dt_setup_arch(void *bph);
 
 #define dt_setup_arch(sym)						\
 ({									\
-	extern struct boot_param_header __dtb_##sym##_begin;		\
+	extern char __dtb_##sym##_begin[];				\
 									\
-	__dt_setup_arch(&__dtb_##sym##_begin);				\
+	__dt_setup_arch(__dtb_##sym##_begin);				\
 })
 
 #else /* CONFIG_OF */
diff --git a/arch/mips/kernel/prom.c b/arch/mips/kernel/prom.c
index 3c3b0df8f48d..5d39bb85bf35 100644
--- a/arch/mips/kernel/prom.c
+++ b/arch/mips/kernel/prom.c
@@ -47,7 +47,7 @@ void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
 	return __alloc_bootmem(size, align, __pa(MAX_DMA_ADDRESS));
 }
 
-void __init __dt_setup_arch(struct boot_param_header *bph)
+void __init __dt_setup_arch(void *bph)
 {
 	if (!early_init_dt_scan(bph))
 		return;
diff --git a/arch/mips/lantiq/prom.c b/arch/mips/lantiq/prom.c
index 19686c5bc5ed..7447d322d14e 100644
--- a/arch/mips/lantiq/prom.c
+++ b/arch/mips/lantiq/prom.c
@@ -71,23 +71,12 @@ void __init plat_mem_setup(void)
 	 * Load the builtin devicetree. This causes the chosen node to be
 	 * parsed resulting in our memory appearing
 	 */
-	__dt_setup_arch(&__dtb_start);
+	__dt_setup_arch(__dtb_start);
 }
 
 void __init device_tree_init(void)
 {
-	unsigned long base, size;
-
-	if (!initial_boot_params)
-		return;
-
-	base = virt_to_phys((void *)initial_boot_params);
-	size = be32_to_cpu(initial_boot_params->totalsize);
-
-	/* Before we do anything, lets reserve the dt blob */
-	reserve_bootmem(base, size, BOOTMEM_DEFAULT);
-
-	unflatten_device_tree();
+	unflatten_and_copy_device_tree();
 }
 
 void __init prom_init(void)
diff --git a/arch/mips/lantiq/prom.h b/arch/mips/lantiq/prom.h
index 8e07b5f28ef1..bfd2d58c1d69 100644
--- a/arch/mips/lantiq/prom.h
+++ b/arch/mips/lantiq/prom.h
@@ -26,6 +26,4 @@ struct ltq_soc_info {
 extern void ltq_soc_detect(struct ltq_soc_info *i);
 extern void ltq_soc_init(void);
 
-extern struct boot_param_header __dtb_start;
-
 #endif
diff --git a/arch/mips/mti-sead3/sead3-setup.c b/arch/mips/mti-sead3/sead3-setup.c
index bf7fe48bf2f9..e43f4801a245 100644
--- a/arch/mips/mti-sead3/sead3-setup.c
+++ b/arch/mips/mti-sead3/sead3-setup.c
@@ -69,17 +69,17 @@ static void __init parse_memsize_param(void)
 	if (!memsize)
 		return;
 
-	offset = fdt_path_offset(&__dtb_start, "/memory");
+	offset = fdt_path_offset(__dtb_start, "/memory");
 	if (offset > 0) {
 		uint64_t new_value;
 		/*
 		 * reg contains 2 32-bits BE values, offset and size. We just
 		 * want to replace the size value without affecting the offset
 		 */
-		prop_value = fdt_getprop(&__dtb_start, offset, "reg", &prop_len);
+		prop_value = fdt_getprop(__dtb_start, offset, "reg", &prop_len);
 		new_value = be64_to_cpu(*prop_value);
 		new_value =  (new_value & ~0xffffffffllu) | memsize;
-		fdt_setprop_inplace_u64(&__dtb_start, offset, "reg", new_value);
+		fdt_setprop_inplace_u64(__dtb_start, offset, "reg", new_value);
 	}
 }
 
@@ -92,7 +92,7 @@ void __init plat_mem_setup(void)
 	 * Load the builtin devicetree. This causes the chosen node to be
 	 * parsed resulting in our memory appearing
 	 */
-	__dt_setup_arch(&__dtb_start);
+	__dt_setup_arch(__dtb_start);
 }
 
 void __init device_tree_init(void)
diff --git a/arch/mips/netlogic/xlp/dt.c b/arch/mips/netlogic/xlp/dt.c
index 5754097b9cde..bdde33147bce 100644
--- a/arch/mips/netlogic/xlp/dt.c
+++ b/arch/mips/netlogic/xlp/dt.c
@@ -42,7 +42,7 @@
 #include <asm/prom.h>
 
 extern u32 __dtb_xlp_evp_begin[], __dtb_xlp_svp_begin[],
-	__dtb_xlp_fvp_begin[], __dtb_xlp_gvp_begin[], __dtb_start[];
+	__dtb_xlp_fvp_begin[], __dtb_xlp_gvp_begin[];
 static void *xlp_fdt_blob;
 
 void __init *xlp_dt_init(void *fdtp)
@@ -87,22 +87,7 @@ void __init xlp_early_init_devtree(void)
 
 void __init device_tree_init(void)
 {
-	unsigned long base, size;
-	struct boot_param_header *fdtp = xlp_fdt_blob;
-
-	if (!fdtp)
-		return;
-
-	base = virt_to_phys(fdtp);
-	size = be32_to_cpu(fdtp->totalsize);
-
-	/* Before we do anything, lets reserve the dt blob */
-	reserve_bootmem(base, size, BOOTMEM_DEFAULT);
-
-	unflatten_device_tree();
-
-	/* free the space reserved for the dt blob */
-	free_bootmem(base, size);
+	unflatten_and_copy_device_tree();
 }
 
 static struct of_device_id __initdata xlp_ids[] = {
diff --git a/arch/mips/ralink/of.c b/arch/mips/ralink/of.c
index eccc5526155e..251395210e23 100644
--- a/arch/mips/ralink/of.c
+++ b/arch/mips/ralink/of.c
@@ -28,8 +28,6 @@
 __iomem void *rt_sysc_membase;
 __iomem void *rt_memc_membase;
 
-extern struct boot_param_header __dtb_start;
-
 __iomem void *plat_of_remap_node(const char *node)
 {
 	struct resource res;
@@ -52,30 +50,7 @@ __iomem void *plat_of_remap_node(const char *node)
 
 void __init device_tree_init(void)
 {
-	unsigned long base, size;
-	void *fdt_copy;
-
-	if (!initial_boot_params)
-		return;
-
-	base = virt_to_phys((void *)initial_boot_params);
-	size = be32_to_cpu(initial_boot_params->totalsize);
-
-	/* Before we do anything, lets reserve the dt blob */
-	reserve_bootmem(base, size, BOOTMEM_DEFAULT);
-
-	/* The strings in the flattened tree are referenced directly by the
-	 * device tree, so copy the flattened device tree from init memory
-	 * to regular memory.
-	 */
-	fdt_copy = alloc_bootmem(size);
-	memcpy(fdt_copy, initial_boot_params, size);
-	initial_boot_params = fdt_copy;
-
-	unflatten_device_tree();
-
-	/* free the space reserved for the dt blob */
-	free_bootmem(base, size);
+	unflatten_and_copy_device_tree();
 }
 
 void __init plat_mem_setup(void)
@@ -86,7 +61,7 @@ void __init plat_mem_setup(void)
 	 * Load the builtin devicetree. This causes the chosen node to be
 	 * parsed resulting in our memory appearing
 	 */
-	__dt_setup_arch(&__dtb_start);
+	__dt_setup_arch(__dtb_start);
 
 	if (soc_info.mem_size)
 		add_memory_region(soc_info.mem_base, soc_info.mem_size * SZ_1M,
diff --git a/arch/openrisc/kernel/vmlinux.h b/arch/openrisc/kernel/vmlinux.h
index 70b9ce41835c..bbcdf21b0b35 100644
--- a/arch/openrisc/kernel/vmlinux.h
+++ b/arch/openrisc/kernel/vmlinux.h
@@ -5,6 +5,4 @@
 extern char __initrd_start, __initrd_end;
 #endif
 
-extern u32 __dtb_start[];
-
 #endif
diff --git a/arch/powerpc/include/asm/dcr-mmio.h b/arch/powerpc/include/asm/dcr-mmio.h
index acd491dbd45a..93a68b28e695 100644
--- a/arch/powerpc/include/asm/dcr-mmio.h
+++ b/arch/powerpc/include/asm/dcr-mmio.h
@@ -51,10 +51,6 @@ static inline void dcr_write_mmio(dcr_host_mmio_t host,
 	out_be32(host.token + ((host.base + dcr_n) * host.stride), value);
 }
 
-extern u64 of_translate_dcr_address(struct device_node *dev,
-				    unsigned int dcr_n,
-				    unsigned int *stride);
-
 #endif /* __KERNEL__ */
 #endif /* _ASM_POWERPC_DCR_MMIO_H */
 
diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index d977b9b78696..74b79f07f041 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -26,6 +26,45 @@
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
 
+#define OF_DT_BEGIN_NODE	0x1		/* Start of node, full name */
+#define OF_DT_END_NODE		0x2		/* End node */
+#define OF_DT_PROP		0x3		/* Property: name off, size,
+						 * content */
+#define OF_DT_NOP		0x4		/* nop */
+#define OF_DT_END		0x9
+
+#define OF_DT_VERSION		0x10
+
+/*
+ * This is what gets passed to the kernel by prom_init or kexec
+ *
+ * The dt struct contains the device tree structure, full pathes and
+ * property contents. The dt strings contain a separate block with just
+ * the strings for the property names, and is fully page aligned and
+ * self contained in a page, so that it can be kept around by the kernel,
+ * each property name appears only once in this page (cheap compression)
+ *
+ * the mem_rsvmap contains a map of reserved ranges of physical memory,
+ * passing it here instead of in the device-tree itself greatly simplifies
+ * the job of everybody. It's just a list of u64 pairs (base/size) that
+ * ends when size is 0
+ */
+struct boot_param_header {
+	__be32	magic;			/* magic word OF_DT_HEADER */
+	__be32	totalsize;		/* total size of DT block */
+	__be32	off_dt_struct;		/* offset to structure */
+	__be32	off_dt_strings;		/* offset to strings */
+	__be32	off_mem_rsvmap;		/* offset to memory reserve map */
+	__be32	version;		/* format version */
+	__be32	last_comp_version;	/* last compatible version */
+	/* version 2 fields below */
+	__be32	boot_cpuid_phys;	/* Physical CPU id we're booting on */
+	/* version 3 fields below */
+	__be32	dt_strings_size;	/* size of the DT strings block */
+	/* version 17 fields below */
+	__be32	dt_struct_size;		/* size of the DT structure block */
+};
+
 /*
  * OF address retreival & translation
  */
diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile
index fcc9a89a4695..fab19ec25597 100644
--- a/arch/powerpc/kernel/Makefile
+++ b/arch/powerpc/kernel/Makefile
@@ -2,6 +2,7 @@
 # Makefile for the linux kernel.
 #
 
+CFLAGS_prom.o		= -I$(src)/../../../scripts/dtc/libfdt
 CFLAGS_ptrace.o		+= -DUTS_MACHINE='"$(UTS_MACHINE)"'
 
 subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
diff --git a/arch/powerpc/kernel/epapr_paravirt.c b/arch/powerpc/kernel/epapr_paravirt.c
index d9b79358b833..60d1a2259dbe 100644
--- a/arch/powerpc/kernel/epapr_paravirt.c
+++ b/arch/powerpc/kernel/epapr_paravirt.c
@@ -36,7 +36,7 @@ static int __init early_init_dt_scan_epapr(unsigned long node,
 					   int depth, void *data)
 {
 	const u32 *insts;
-	unsigned long len;
+	int len;
 	int i;
 
 	insts = of_get_flat_dt_prop(node, "hcall-instructions", &len);
diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 2230fd0ca3e4..7213d930918d 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -55,9 +55,9 @@ int crash_mem_ranges;
 int __init early_init_dt_scan_fw_dump(unsigned long node,
 			const char *uname, int depth, void *data)
 {
-	__be32 *sections;
+	const __be32 *sections;
 	int i, num_sections;
-	unsigned long size;
+	int size;
 	const int *token;
 
 	if (depth != 1 || strcmp(uname, "rtas") != 0)
diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 668aa4791fd7..613a860a203c 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c
@@ -29,11 +29,11 @@
 #include <linux/bitops.h>
 #include <linux/export.h>
 #include <linux/kexec.h>
-#include <linux/debugfs.h>
 #include <linux/irq.h>
 #include <linux/memblock.h>
 #include <linux/of.h>
 #include <linux/of_fdt.h>
+#include <linux/libfdt.h>
 
 #include <asm/prom.h>
 #include <asm/rtas.h>
@@ -118,14 +118,14 @@ static void __init move_device_tree(void)
 	DBG("-> move_device_tree\n");
 
 	start = __pa(initial_boot_params);
-	size = be32_to_cpu(initial_boot_params->totalsize);
+	size = fdt_totalsize(initial_boot_params);
 
 	if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
 			overlaps_crashkernel(start, size) ||
 			overlaps_initrd(start, size)) {
 		p = __va(memblock_alloc(size, PAGE_SIZE));
 		memcpy(p, initial_boot_params, size);
-		initial_boot_params = (struct boot_param_header *)p;
+		initial_boot_params = p;
 		DBG("Moved device tree to 0x%p\n", p);
 	}
 
@@ -163,7 +163,7 @@ static struct ibm_pa_feature {
 	{CPU_FTR_REAL_LE, PPC_FEATURE_TRUE_LE, 5, 0, 0},
 };
 
-static void __init scan_features(unsigned long node, unsigned char *ftrs,
+static void __init scan_features(unsigned long node, const unsigned char *ftrs,
 				 unsigned long tablelen,
 				 struct ibm_pa_feature *fp,
 				 unsigned long ft_size)
@@ -202,8 +202,8 @@ static void __init scan_features(unsigned long node, unsigned char *ftrs,
 
 static void __init check_cpu_pa_features(unsigned long node)
 {
-	unsigned char *pa_ftrs;
-	unsigned long tablelen;
+	const unsigned char *pa_ftrs;
+	int tablelen;
 
 	pa_ftrs = of_get_flat_dt_prop(node, "ibm,pa-features", &tablelen);
 	if (pa_ftrs == NULL)
@@ -216,7 +216,7 @@ static void __init check_cpu_pa_features(unsigned long node)
 #ifdef CONFIG_PPC_STD_MMU_64
 static void __init check_cpu_slb_size(unsigned long node)
 {
-	__be32 *slb_size_ptr;
+	const __be32 *slb_size_ptr;
 
 	slb_size_ptr = of_get_flat_dt_prop(node, "slb-size", NULL);
 	if (slb_size_ptr != NULL) {
@@ -257,7 +257,7 @@ static struct feature_property {
 static inline void identical_pvr_fixup(unsigned long node)
 {
 	unsigned int pvr;
-	char *model = of_get_flat_dt_prop(node, "model", NULL);
+	const char *model = of_get_flat_dt_prop(node, "model", NULL);
 
 	/*
 	 * Since 440GR(x)/440EP(x) processors have the same pvr,
@@ -295,11 +295,11 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 					  const char *uname, int depth,
 					  void *data)
 {
-	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
 	const __be32 *prop;
 	const __be32 *intserv;
 	int i, nthreads;
-	unsigned long len;
+	int len;
 	int found = -1;
 	int found_thread = 0;
 
@@ -325,9 +325,9 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 		 * version 2 of the kexec param format adds the phys cpuid of
 		 * booted proc.
 		 */
-		if (be32_to_cpu(initial_boot_params->version) >= 2) {
+		if (fdt_version(initial_boot_params) >= 2) {
 			if (be32_to_cpu(intserv[i]) ==
-			    be32_to_cpu(initial_boot_params->boot_cpuid_phys)) {
+			    fdt_boot_cpuid_phys(initial_boot_params)) {
 				found = boot_cpu_count;
 				found_thread = i;
 			}
@@ -392,7 +392,7 @@ static int __init early_init_dt_scan_cpus(unsigned long node,
 int __init early_init_dt_scan_chosen_ppc(unsigned long node, const char *uname,
 					 int depth, void *data)
 {
-	unsigned long *lprop; /* All these set by kernel, so no need to convert endian */
+	const unsigned long *lprop; /* All these set by kernel, so no need to convert endian */
 
 	/* Use common scan routine to determine if this is the chosen node */
 	if (early_init_dt_scan_chosen(node, uname, depth, data) == 0)
@@ -443,8 +443,9 @@ int __init early_init_dt_scan_chosen_ppc(unsigned long node, const char *uname,
  */
 static int __init early_init_dt_scan_drconf_memory(unsigned long node)
 {
-	__be32 *dm, *ls, *usm;
-	unsigned long l, n, flags;
+	const __be32 *dm, *ls, *usm;
+	int l;
+	unsigned long n, flags;
 	u64 base, size, memblock_size;
 	unsigned int is_kexec_kdump = 0, rngs;
 
@@ -564,9 +565,12 @@ void __init early_init_dt_add_memory_arch(u64 base, u64 size)
 
 static void __init early_reserve_mem_dt(void)
 {
-	unsigned long i, len, dt_root;
+	unsigned long i, dt_root;
+	int len;
 	const __be32 *prop;
 
+	early_init_fdt_scan_reserved_mem();
+
 	dt_root = of_get_flat_dt_root();
 
 	prop = of_get_flat_dt_prop(dt_root, "reserved-ranges", &len);
@@ -589,24 +593,14 @@ static void __init early_reserve_mem_dt(void)
 			memblock_reserve(base, size);
 		}
 	}
-
-	early_init_fdt_scan_reserved_mem();
 }
 
 static void __init early_reserve_mem(void)
 {
-	u64 base, size;
 	__be64 *reserve_map;
-	unsigned long self_base;
-	unsigned long self_size;
 
 	reserve_map = (__be64 *)(((unsigned long)initial_boot_params) +
-			be32_to_cpu(initial_boot_params->off_mem_rsvmap));
-
-	/* before we do anything, lets reserve the dt blob */
-	self_base = __pa((unsigned long)initial_boot_params);
-	self_size = be32_to_cpu(initial_boot_params->totalsize);
-	memblock_reserve(self_base, self_size);
+			fdt_off_mem_rsvmap(initial_boot_params));
 
 	/* Look for the new "reserved-regions" property in the DT */
 	early_reserve_mem_dt();
@@ -636,26 +630,12 @@ static void __init early_reserve_mem(void)
 			size_32 = be32_to_cpup(reserve_map_32++);
 			if (size_32 == 0)
 				break;
-			/* skip if the reservation is for the blob */
-			if (base_32 == self_base && size_32 == self_size)
-				continue;
 			DBG("reserving: %x -> %x\n", base_32, size_32);
 			memblock_reserve(base_32, size_32);
 		}
 		return;
 	}
 #endif
-	DBG("Processing reserve map\n");
-
-	/* Handle the reserve map in the fdt blob if it exists */
-	while (1) {
-		base = be64_to_cpup(reserve_map++);
-		size = be64_to_cpup(reserve_map++);
-		if (size == 0)
-			break;
-		DBG("reserving: %llx -> %llx\n", base, size);
-		memblock_reserve(base, size);
-	}
 }
 
 void __init early_init_devtree(void *params)
@@ -922,23 +902,3 @@ bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {
 	return (int)phys_id == get_hard_smp_processor_id(cpu);
 }
-
-#if defined(CONFIG_DEBUG_FS) && defined(DEBUG)
-static struct debugfs_blob_wrapper flat_dt_blob;
-
-static int __init export_flat_device_tree(void)
-{
-	struct dentry *d;
-
-	flat_dt_blob.data = initial_boot_params;
-	flat_dt_blob.size = be32_to_cpu(initial_boot_params->totalsize);
-
-	d = debugfs_create_blob("flat-device-tree", S_IFREG | S_IRUSR,
-				powerpc_debugfs_root, &flat_dt_blob);
-	if (!d)
-		return 1;
-
-	return 0;
-}
-__initcall(export_flat_device_tree);
-#endif
diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
index 8cd5ed049b5d..8b4c857c1421 100644
--- a/arch/powerpc/kernel/rtas.c
+++ b/arch/powerpc/kernel/rtas.c
@@ -1142,7 +1142,7 @@ void __init rtas_initialize(void)
 int __init early_init_dt_scan_rtas(unsigned long node,
 		const char *uname, int depth, void *data)
 {
-	u32 *basep, *entryp, *sizep;
+	const u32 *basep, *entryp, *sizep;
 
 	if (depth != 1 || strcmp(uname, "rtas") != 0)
 		return 0;
diff --git a/arch/powerpc/mm/hash_utils_64.c b/arch/powerpc/mm/hash_utils_64.c
index 06ba83b036d3..350aa58a6f95 100644
--- a/arch/powerpc/mm/hash_utils_64.c
+++ b/arch/powerpc/mm/hash_utils_64.c
@@ -269,9 +269,9 @@ static int __init htab_dt_scan_seg_sizes(unsigned long node,
 					 const char *uname, int depth,
 					 void *data)
 {
-	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
-	__be32 *prop;
-	unsigned long size = 0;
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+	const __be32 *prop;
+	int size = 0;
 
 	/* We are scanning "cpu" nodes only */
 	if (type == NULL || strcmp(type, "cpu") != 0)
@@ -324,9 +324,9 @@ static int __init htab_dt_scan_page_sizes(unsigned long node,
 					  const char *uname, int depth,
 					  void *data)
 {
-	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
-	__be32 *prop;
-	unsigned long size = 0;
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+	const __be32 *prop;
+	int size = 0;
 
 	/* We are scanning "cpu" nodes only */
 	if (type == NULL || strcmp(type, "cpu") != 0)
@@ -406,9 +406,9 @@ static int __init htab_dt_scan_page_sizes(unsigned long node,
 static int __init htab_dt_scan_hugepage_blocks(unsigned long node,
 					const char *uname, int depth,
 					void *data) {
-	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
-	__be64 *addr_prop;
-	__be32 *page_count_prop;
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+	const __be64 *addr_prop;
+	const __be32 *page_count_prop;
 	unsigned int expected_pages;
 	long unsigned int phys_addr;
 	long unsigned int block_size;
@@ -550,8 +550,8 @@ static int __init htab_dt_scan_pftsize(unsigned long node,
 				       const char *uname, int depth,
 				       void *data)
 {
-	char *type = of_get_flat_dt_prop(node, "device_type", NULL);
-	__be32 *prop;
+	const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
+	const __be32 *prop;
 
 	/* We are scanning "cpu" nodes only */
 	if (type == NULL || strcmp(type, "cpu") != 0)
diff --git a/arch/powerpc/platforms/52xx/efika.c b/arch/powerpc/platforms/52xx/efika.c
index 18c104820198..6e19b0ad5d26 100644
--- a/arch/powerpc/platforms/52xx/efika.c
+++ b/arch/powerpc/platforms/52xx/efika.c
@@ -199,8 +199,8 @@ static void __init efika_setup_arch(void)
 
 static int __init efika_probe(void)
 {
-	char *model = of_get_flat_dt_prop(of_get_flat_dt_root(),
-					  "model", NULL);
+	const char *model = of_get_flat_dt_prop(of_get_flat_dt_root(),
+						"model", NULL);
 
 	if (model == NULL)
 		return 0;
diff --git a/arch/powerpc/platforms/chrp/setup.c b/arch/powerpc/platforms/chrp/setup.c
index c665d7de6c99..7044fd36197b 100644
--- a/arch/powerpc/platforms/chrp/setup.c
+++ b/arch/powerpc/platforms/chrp/setup.c
@@ -574,8 +574,8 @@ chrp_init2(void)
 
 static int __init chrp_probe(void)
 {
- 	char *dtype = of_get_flat_dt_prop(of_get_flat_dt_root(),
- 					  "device_type", NULL);
+	const char *dtype = of_get_flat_dt_prop(of_get_flat_dt_root(),
+						"device_type", NULL);
  	if (dtype == NULL)
  		return 0;
  	if (strcmp(dtype, "chrp"))
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 360ad80c754c..f343183add07 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -61,7 +61,7 @@ int __init early_init_dt_scan_opal(unsigned long node,
 				   const char *uname, int depth, void *data)
 {
 	const void *basep, *entryp, *sizep;
-	unsigned long basesz, entrysz, runtimesz;
+	int basesz, entrysz, runtimesz;
 
 	if (depth != 1 || strcmp(uname, "ibm,opal") != 0)
 		return 0;
@@ -77,11 +77,11 @@ int __init early_init_dt_scan_opal(unsigned long node,
 	opal.entry = of_read_number(entryp, entrysz/4);
 	opal.size = of_read_number(sizep, runtimesz/4);
 
-	pr_debug("OPAL Base  = 0x%llx (basep=%p basesz=%ld)\n",
+	pr_debug("OPAL Base  = 0x%llx (basep=%p basesz=%d)\n",
 		 opal.base, basep, basesz);
-	pr_debug("OPAL Entry = 0x%llx (entryp=%p basesz=%ld)\n",
+	pr_debug("OPAL Entry = 0x%llx (entryp=%p basesz=%d)\n",
 		 opal.entry, entryp, entrysz);
-	pr_debug("OPAL Entry = 0x%llx (sizep=%p runtimesz=%ld)\n",
+	pr_debug("OPAL Entry = 0x%llx (sizep=%p runtimesz=%d)\n",
 		 opal.size, sizep, runtimesz);
 
 	powerpc_firmware_features |= FW_FEATURE_OPAL;
@@ -102,7 +102,7 @@ int __init early_init_dt_scan_opal(unsigned long node,
 int __init early_init_dt_scan_recoverable_ranges(unsigned long node,
 				   const char *uname, int depth, void *data)
 {
-	unsigned long i, psize, size;
+	int i, psize, size;
 	const __be32 *prop;
 
 	if (depth != 1 || strcmp(uname, "ibm,opal") != 0)
@@ -359,7 +359,7 @@ int opal_get_chars(uint32_t vtermno, char *buf, int count)
 	if ((be64_to_cpu(evt) & OPAL_EVENT_CONSOLE_INPUT) == 0)
 		return 0;
 	len = cpu_to_be64(count);
-	rc = opal_console_read(vtermno, &len, buf);	
+	rc = opal_console_read(vtermno, &len, buf);
 	if (rc == OPAL_SUCCESS)
 		return be64_to_cpu(len);
 	return 0;
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 2db8cc691bf4..099d2df976a2 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -665,7 +665,7 @@ static int __init pseries_probe_fw_features(unsigned long node,
 					    void *data)
 {
 	const char *prop;
-	unsigned long len;
+	int len;
 	static int hypertas_found;
 	static int vec5_found;
 
@@ -698,7 +698,7 @@ static int __init pseries_probe_fw_features(unsigned long node,
 static int __init pSeries_probe(void)
 {
 	unsigned long root = of_get_flat_dt_root();
- 	char *dtype = of_get_flat_dt_prop(root, "device_type", NULL);
+	const char *dtype = of_get_flat_dt_prop(root, "device_type", NULL);
 
  	if (dtype == NULL)
  		return 0;
diff --git a/arch/powerpc/sysdev/dcr.c b/arch/powerpc/sysdev/dcr.c
index 1bd0eba4d355..e9056e438575 100644
--- a/arch/powerpc/sysdev/dcr.c
+++ b/arch/powerpc/sysdev/dcr.c
@@ -152,9 +152,9 @@ EXPORT_SYMBOL_GPL(dcr_resource_len);
 
 #ifdef CONFIG_PPC_DCR_MMIO
 
-u64 of_translate_dcr_address(struct device_node *dev,
-			     unsigned int dcr_n,
-			     unsigned int *out_stride)
+static u64 of_translate_dcr_address(struct device_node *dev,
+				    unsigned int dcr_n,
+				    unsigned int *out_stride)
 {
 	struct device_node *dp;
 	const u32 *p;
diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index d35078ea1446..7db54b5d5f86 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c
@@ -206,23 +206,21 @@ static void __init dtb_apic_setup(void)
 static void __init x86_flattree_get_config(void)
 {
 	u32 size, map_len;
-	struct boot_param_header *dt;
+	void *dt;
 
 	if (!initial_dtb)
 		return;
 
-	map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK),
-			(u64)sizeof(struct boot_param_header));
+	map_len = max(PAGE_SIZE - (initial_dtb & ~PAGE_MASK), (u64)128);
 
-	dt = early_memremap(initial_dtb, map_len);
-	size = be32_to_cpu(dt->totalsize);
+	initial_boot_params = dt = early_memremap(initial_dtb, map_len);
+	size = of_get_flat_dt_size();
 	if (map_len < size) {
 		early_iounmap(dt, map_len);
-		dt = early_memremap(initial_dtb, size);
+		initial_boot_params = dt = early_memremap(initial_dtb, size);
 		map_len = size;
 	}
 
-	initial_boot_params = dt;
 	unflatten_and_copy_device_tree();
 	early_iounmap(dt, map_len);
 }
diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index 9757bb74e532..06370ccea9e9 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c
@@ -74,7 +74,6 @@ extern int initrd_below_start_ok;
 #endif
 
 #ifdef CONFIG_OF
-extern u32 __dtb_start[];
 void *dtb_start = __dtb_start;
 #endif
 
@@ -199,7 +198,7 @@ static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
 		int depth, void *data)
 {
 	const __be32 *ranges;
-	unsigned long len;
+	int len;
 
 	if (depth > 1)
 		return 0;