[RFC 0/2] Appended Device Tree

[RFC 0/2] Appended Device Tree

[John Bonesio]

This not intended to be merged. This is a request for comments on the approach
being taken.

The following series implements a prototype/proof of concept for allowing a
device-tree binary (dtb) to be appended to the end of zImage. The dtb can be
appended with a command like:
   cat zImage myboard.dtb > zImage_w_dtb.

The purpose is to allow a single kernel to be built for multiple boards/systems
and allow a simple process to apply the right device tree right before the
kernel image is written into flash. This way the system that applies the
device tree doesn't have to have the full gnu compiler set installed.

The old behavior has not changed. If a dtb is not appended, the kernel will
still boot as expected.

The frst patch detects if a dtb is present at the end of the zImage and uses
it, if present. The second patch merges in a couple of key atags, if present,
into the appended device-tree, if found.

With the new kernel config option enabled, this patch adds 11400 bytes to
zImage. The kernel code itself doesn't change size.
The first patch in this series adds 96 bytes to zImage.
The second patch in this series adds 11304 bytes to zImage.

These numbers vary depending on the kernel version, probably due to alignment requirements.


---

John Bonesio (2):
      ARM:boot:device tree: Allow the device tree binary to be appended to zImage
      ARM:boot:device tree: Merge specific atags into the device tree


 arch/arm/Kconfig                  |    7 ++++
 arch/arm/boot/compressed/Makefile |   31 ++++++++++++++++---
 arch/arm/boot/compressed/atags.c  |   50 +++++++++++++++++++++++++++++++
 arch/arm/boot/compressed/head.S   |   59 ++++++++++++++++++++++++++++++++++++-
 arch/arm/boot/compressed/misc.c   |   58 +++++++++++++++++++++++++++++++++++-
 5 files changed, 196 insertions(+), 9 deletions(-)
 create mode 100644 arch/arm/boot/compressed/atags.c

-- 
Signature

[RFC 1/2] ARM:boot:device tree: Allow the device tree binary to be appended to zImage

[John Bonesio]

This patch provides the ability to boot using a device tree that is appended
to the raw binary zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb).

Constraints:
1) A maximum 16k device tree binary is copied to memory at 0x0. If the device
   tree is bigger than 16k, the kernel will probably fail ungracefully - unless
   there is a device tree already embedded in the zImage.

Signed-off-by: John Bonesio <bones@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
---

 arch/arm/Kconfig                |    7 +++++
 arch/arm/boot/compressed/head.S |   52 ++++++++++++++++++++++++++++++++++++++-
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index d8a330f..e63a441 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -1593,6 +1593,13 @@ config USE_OF
 	help
 	  Include support for flattened device tree machine descriptions.
 
+config ARM_APPENDED_DTB
+	bool "Use appended device tree blob" if OF
+	default n
+	help
+	  With this option, the boot code will look for a dtb bianry
+	  appended to zImage.
+
 # Compressed boot loader in ROM.  Yes, we really want to ask about
 # TEXT and BSS so we preserve their values in the config files.
 config ZBOOT_ROM_TEXT
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index 7193884..db860b3 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -138,7 +138,7 @@ start:
 		b	1f
 		.word	0x016f2818		@ Magic numbers to help the loader
 		.word	start			@ absolute load/run zImage address
-		.word	_edata			@ zImage end address
+DTB:		.word	_edata			@ zImage end address
  THUMB(		.thumb			)
 1:		mov	r7, r1			@ save architecture ID
 		mov	r8, r2			@ save atags pointer
@@ -173,6 +173,9 @@ not_angel:
 		 * by the linker here, but it should preserve r7, r8, and r9.
 		 */
 
+		/* Check if there is an appended device tree binary */
+		ldr	r10, DTB			@ get the address of _dtb
+
 		.text
 		adr	r0, LC0
 		ldmia	r0, {r1, r2, r3, r5, r6, r11, ip}
@@ -196,10 +199,12 @@ not_angel:
 		 * up various pointers:
 		 *   r5 - zImage base address (_start)
 		 *   r6 - size of decompressed image
+		 *   r10 - zImage end
 		 *   r11 - GOT start
 		 *   ip - GOT end
 		 */
 		add	r5, r5, r0
+		add	r10, r10, r0
 		add	r11, r11, r0
 		add	ip, ip, r0
 
@@ -215,6 +220,7 @@ not_angel:
 		add	r3, r3, r0
 		add	sp, sp, r0
 
+
 		/*
 		 * Relocate all entries in the GOT table.
 		 */
@@ -238,7 +244,49 @@ not_angel:
 		blo	1b
 #endif
 
-not_relocated:	mov	r0, #0
+not_relocated:
+#ifdef CONFIG_ARM_APPENDED_DTB
+		/*
+		 * Check if there is an appended device tree binary, by testing
+		 * for the device tree magic signature
+		 *
+		 * An appended device tree will be at the end of the zImage
+		 */
+		ldr	r1, [r10, #0]
+		ldr	r9, =0xedfe0dd0	@ sig is 0xdoodfeed stored big endian
+		cmp	r1, r9
+		bne	keep_atags
+
+		/* copy the device tree binary to 0x0 */
+		ldr	r9, [r10, #4]	@ device tree size
+
+		/* convert r9 (dtb size) to little endian */
+		eor	r1, r9, r9, ror #16
+		bic	r1, r1, #0x00ff0000
+		mov	r9, r9, ror #8
+		eor	r9, r9, r1, lsr #8
+
+		/* make sure the device tree isn't too big */
+		mov	r0, #16384
+		cmp	r9, r0
+		bhi	keep_atags
+
+		mov	r0, r2
+		mov	r1, #0x0
+		add	r9, r1		@ size to address from target location
+1:
+		.rept	4
+		ldmia	r0!, {r10}	@ relocate device tree
+		stmia	r1!, {r10}
+		.endr
+		cmp	r1, r9
+		blo	1b
+		mov	r8, #0x0
+
+keep_atags:
+#endif
+
+__not_relocated:	mov	r0, #0
 1:		str	r0, [r2], #4		@ clear bss
 		str	r0, [r2], #4
 		str	r0, [r2], #4

[RFC 2/2] ARM:boot:device tree: Merge specific atags into the device tree

[John Bonesio]

This patch is to merge in key atags into the appended device tree.  An appended
device tree is where the zImage has a dtb binary appended at the end of it. The
boot code looks for an appended device tree, then looks for a few key atags
passed in by the bootloader.

The bootargs and memory size settings, if they exist, override existing values
in the appended device tree. If these values don't currently exist in the
appended device tree, they are added.

Signed-off-by: John Bonesio <bones@secretlab.ca>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
---

 arch/arm/boot/compressed/Makefile |   31 +++++++++++++++++---
 arch/arm/boot/compressed/atags.c  |   50 ++++++++++++++++++++++++++++++++
 arch/arm/boot/compressed/head.S   |    7 ++++
 arch/arm/boot/compressed/misc.c   |   58 ++++++++++++++++++++++++++++++++++++-
 4 files changed, 139 insertions(+), 7 deletions(-)
 create mode 100644 arch/arm/boot/compressed/atags.c

diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index 0a8f748..7978a39 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -49,6 +49,10 @@ ifeq ($(CONFIG_ARCH_SHMOBILE),y)
 OBJS		+= head-shmobile.o
 endif
 
+ifeq ($(CONFIG_ARM_APPENDED_DTB),y)
+OBJS		+= atags.o libfdt.a 
+endif
+
 #
 # We now have a PIC decompressor implementation.  Decompressors running
 # from RAM should not define ZTEXTADDR.  Decompressors running directly
@@ -80,7 +84,9 @@ ORIG_CFLAGS := $(KBUILD_CFLAGS)
 KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
 endif
 
-EXTRA_CFLAGS  := -fpic -fno-builtin
+fdttree      := $(srctree)/scripts/dtc/libfdt
+
+EXTRA_CFLAGS  := -fpic -fno-builtin -I$(fdttree) -I$(obj)
 EXTRA_AFLAGS  := -Wa,-march=all
 
 # Supply ZRELADDR to the decompressor via a linker symbol.
@@ -100,13 +106,28 @@ LDFLAGS_vmlinux += -X
 LDFLAGS_vmlinux += -T
 
 # For __aeabi_uidivmod
-lib1funcs = $(obj)/lib1funcs.o
+libfuncs = $(obj)/lib1funcs.o
 
-$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
-	$(call cmd,shipped)
+ifeq ($(CONFIG_ARM_APPENDED_DTB),y)
+# For memchr, memmove, etc
+libfuncs += $(obj)/memchr.o $(obj)/strchr.o $(obj)/memmove.o $(obj)/memzero.o
+endif
+
+
+libfdtheader := $(fdttree)/fdt.h $(fdttree)/libfdt.h $(fdttree)/libfdt_internal.h
+libfdtobj    := $(obj)/fdt.o $(obj)/fdt_ro.o $(obj)/fdt_wip.o $(obj)/fdt_sw.o $(obj)/fdt_rw.o $(obj)/fdt_strerror.o
+
+$(libfdtobj): $(obj)/%.o: $(srctree)/scripts/dtc/libfdt/%.c $(libfdtheader)
+	$(call cmd_cc_o_c)
+
+$(obj)/libfdt.a: $(libfdtobj)
+	$(AR) rcs $@ $^
+
+$(libfuncs): $(obj)/%.o: $(srctree)/arch/$(SRCARCH)/lib/%.S
+	$(call cmd_as_o_S)
 
 $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
-	 	$(addprefix $(obj)/, $(OBJS)) $(lib1funcs) FORCE
+	 	$(addprefix $(obj)/, $(OBJS)) $(libfuncs) FORCE
 	$(call if_changed,ld)
 	@:
 
diff --git a/arch/arm/boot/compressed/atags.c b/arch/arm/boot/compressed/atags.c
new file mode 100644
index 0000000..e37d8de
--- /dev/null
+++ b/arch/arm/boot/compressed/atags.c
@@ -0,0 +1,50 @@
+#include <stddef.h>
+#include <asm/byteorder.h>
+#include <asm/setup.h>
+#include <fdt.h>
+#include <libfdt.h>
+
+
+int dt_setprop(void *fdt, const char *node_path, const char *property,
+               uint32_t *val_array, int size)
+{
+	int offset;
+
+	offset = fdt_path_offset(fdt, node_path);
+	if (offset < 0)
+		return offset;
+
+	return fdt_setprop(fdt, offset, property, val_array, size);
+}
+
+int dt_setprop_string(void *fdt, const char *node_path,
+                      const char *property, const char *string)
+{
+	int offset;
+		
+	offset = fdt_path_offset(fdt, node_path);
+	if (offset < 0)
+		return offset;
+			
+	return fdt_setprop_string(fdt, offset, property, string);
+}
+
+void dt_merge_atags(void *dt,  void *ataglist)
+{
+	struct tag *atag = ataglist;
+	uint32_t mem_reg_property[2];
+
+	while (atag && atag->hdr.tag != 0) {
+		if (atag->hdr.tag == ATAG_CMDLINE) {
+			dt_setprop_string(dt, "/chosen", "bootargs",
+			                  atag->u.cmdline.cmdline);
+		} else if (atag->hdr.tag == ATAG_MEM) {
+			mem_reg_property[0] = cpu_to_fdt32(atag->u.mem.start);
+			mem_reg_property[1] = cpu_to_fdt32(atag->u.mem.size);
+			dt_setprop(dt, "/memory", "reg", mem_reg_property,
+			           sizeof(mem_reg_property));
+		}
+		atag = tag_next(atag);
+	}
+}
+
diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
index db860b3..09e659d 100644
--- a/arch/arm/boot/compressed/head.S
+++ b/arch/arm/boot/compressed/head.S
@@ -257,6 +257,13 @@ not_relocated:
 		cmp	r1, r9
 		bne	keep_atags
 
+		/* Merge some of the atags into the device tree */
+		push	{r2, r3, r10, r11}
+		mov	r0, r2
+		mov	r1, r8
+		bl	dt_merge_atags
+		pop	{r2, r3, r10, r11}
+
 		/* copy the device tree binary to 0x0 */
 		ldr	r9, [r10, #4]	@ device tree size
 
diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
index e653a6d..2d4da4c 100644
--- a/arch/arm/boot/compressed/misc.c
+++ b/arch/arm/boot/compressed/misc.c
@@ -29,7 +29,7 @@ unsigned int __machine_arch_type;
 #include <asm/unaligned.h>
 
 
-static void putstr(const char *ptr);
+void putstr(const char *ptr);
 extern void error(char *x);
 
 #include <mach/uncompress.h>
@@ -100,7 +100,7 @@ static void icedcc_putc(int ch)
 #define putc(ch)	icedcc_putc(ch)
 #endif
 
-static void putstr(const char *ptr)
+void putstr(const char *ptr)
 {
 	char c;
 
@@ -114,6 +114,60 @@ static void putstr(const char *ptr)
 }
 
 
+#ifdef CONFIG_ARM_APPENDED_DTB
+/**
+ * strlen - Find the length of a string
+ * @s: The string to be sized
+ */
+size_t strlen(const char *s)
+{
+        const char *sc;
+
+        for (sc = s; *sc != '\0'; ++sc)
+                /* nothing */;
+        return sc - s;
+}
+
+/**
+ * strcmp - Compare two strings
+ * @cs: One string
+ * @ct: Another string
+ */
+#undef strcmp
+int strcmp(const char *cs, const char *ct)
+{
+	unsigned char c1, c2;
+
+	while (1) {
+		c1 = *cs++;
+		c2 = *ct++;
+		if (c1 != c2)
+			return c1 < c2 ? -1 : 1;
+		if (!c1)
+			break;
+	}
+	return 0;
+}
+
+/**
+ * memcmp - Compare two areas of memory
+ * @cs: One area of memory
+ * @ct: Another area of memory
+ * @count: The size of the area.
+ */
+#undef memcmp
+int memcmp(const void *cs, const void *ct, size_t count)
+{
+	const unsigned char *su1, *su2;
+	int res = 0;
+
+	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
+		if ((res = *su1 - *su2) != 0)
+			break;
+	return res;
+}
+#endif
+
 void *memcpy(void *__dest, __const void *__src, size_t __n)
 {
 	int i = 0;

[RFC 1/2] ARM:boot:device tree: Allow the device tree binary to be appended to zImage

[Nicolas Pitre]

On Wed, 26 Jan 2011, John Bonesio wrote:

> This patch provides the ability to boot using a device tree that is appended
> to the raw binary zImage (e.g. cat zImage <filename>.dtb > zImage_w_dtb).
> 
> Constraints:
> 1) A maximum 16k device tree binary is copied to memory at 0x0. If the device
>    tree is bigger than 16k, the kernel will probably fail ungracefully - unless
>    there is a device tree already embedded in the zImage.

This will ungracefully fail on targets where physical memory is not 
located at 0x0.  And this is not an uncommon situation on ARM.

> Signed-off-by: John Bonesio <bones@secretlab.ca>
> Acked-by: Grant Likely <grant.likely@secretlab.ca>

NAK.  This is not the way to go about this.

First of all, there is a bit of a misdesign in the kernel decompressor.  
It currently verifies that the decompressed data destination doesn't 
conflict with the decompressor itself.  If there is indeed an overlap, 
then the decompressor stores the decompressed data above itself and 
relocates that data back to its final location when it is done 
decompressing.

Instead, the decompressor should move _itself_ out of the way rather 
than moving the decompressed data, as that would make for a smaller 
copy.  I'll try to have a look at that part if no one beats me to it.

Once this is "fixed", then all you'll have to do is to simply pass the 
(possibly relocated with the decompressor) address of the dtb data into 
r2 without copying it anywhere else.  That's it, and no 16KB limit.


Nicolas

[RFC 2/2] ARM:boot:device tree: Merge specific atags into the device tree

[Nicolas Pitre]

On Wed, 26 Jan 2011, John Bonesio wrote:

> This patch is to merge in key atags into the appended device tree.  An appended
> device tree is where the zImage has a dtb binary appended at the end of it. The
> boot code looks for an appended device tree, then looks for a few key atags
> passed in by the bootloader.
> 
> The bootargs and memory size settings, if they exist, override existing values
> in the appended device tree. If these values don't currently exist in the
> appended device tree, they are added.
> 
> Signed-off-by: John Bonesio <bones@secretlab.ca>
> Acked-by: Grant Likely <grant.likely@secretlab.ca>

This is just for testing/evaluation purpose and not intended to be 
merged upstream at some point, right?

> ---
> 
>  arch/arm/boot/compressed/Makefile |   31 +++++++++++++++++---
>  arch/arm/boot/compressed/atags.c  |   50 ++++++++++++++++++++++++++++++++
>  arch/arm/boot/compressed/head.S   |    7 ++++
>  arch/arm/boot/compressed/misc.c   |   58 ++++++++++++++++++++++++++++++++++++-
>  4 files changed, 139 insertions(+), 7 deletions(-)
>  create mode 100644 arch/arm/boot/compressed/atags.c
> 
> diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
> index 0a8f748..7978a39 100644
> --- a/arch/arm/boot/compressed/Makefile
> +++ b/arch/arm/boot/compressed/Makefile
> @@ -49,6 +49,10 @@ ifeq ($(CONFIG_ARCH_SHMOBILE),y)
>  OBJS		+= head-shmobile.o
>  endif
>  
> +ifeq ($(CONFIG_ARM_APPENDED_DTB),y)
> +OBJS		+= atags.o libfdt.a 
> +endif
> +
>  #
>  # We now have a PIC decompressor implementation.  Decompressors running
>  # from RAM should not define ZTEXTADDR.  Decompressors running directly
> @@ -80,7 +84,9 @@ ORIG_CFLAGS := $(KBUILD_CFLAGS)
>  KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
>  endif
>  
> -EXTRA_CFLAGS  := -fpic -fno-builtin
> +fdttree      := $(srctree)/scripts/dtc/libfdt
> +
> +EXTRA_CFLAGS  := -fpic -fno-builtin -I$(fdttree) -I$(obj)
>  EXTRA_AFLAGS  := -Wa,-march=all
>  
>  # Supply ZRELADDR to the decompressor via a linker symbol.
> @@ -100,13 +106,28 @@ LDFLAGS_vmlinux += -X
>  LDFLAGS_vmlinux += -T
>  
>  # For __aeabi_uidivmod
> -lib1funcs = $(obj)/lib1funcs.o
> +libfuncs = $(obj)/lib1funcs.o
>  
> -$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
> -	$(call cmd,shipped)
> +ifeq ($(CONFIG_ARM_APPENDED_DTB),y)
> +# For memchr, memmove, etc
> +libfuncs += $(obj)/memchr.o $(obj)/strchr.o $(obj)/memmove.o $(obj)/memzero.o
> +endif
> +
> +
> +libfdtheader := $(fdttree)/fdt.h $(fdttree)/libfdt.h $(fdttree)/libfdt_internal.h
> +libfdtobj    := $(obj)/fdt.o $(obj)/fdt_ro.o $(obj)/fdt_wip.o $(obj)/fdt_sw.o $(obj)/fdt_rw.o $(obj)/fdt_strerror.o
> +
> +$(libfdtobj): $(obj)/%.o: $(srctree)/scripts/dtc/libfdt/%.c $(libfdtheader)
> +	$(call cmd_cc_o_c)
> +
> +$(obj)/libfdt.a: $(libfdtobj)
> +	$(AR) rcs $@ $^
> +
> +$(libfuncs): $(obj)/%.o: $(srctree)/arch/$(SRCARCH)/lib/%.S
> +	$(call cmd_as_o_S)
>  
>  $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD) $(obj)/piggy.$(suffix_y).o \
> -	 	$(addprefix $(obj)/, $(OBJS)) $(lib1funcs) FORCE
> +	 	$(addprefix $(obj)/, $(OBJS)) $(libfuncs) FORCE
>  	$(call if_changed,ld)
>  	@:
>  
> diff --git a/arch/arm/boot/compressed/atags.c b/arch/arm/boot/compressed/atags.c
> new file mode 100644
> index 0000000..e37d8de
> --- /dev/null
> +++ b/arch/arm/boot/compressed/atags.c
> @@ -0,0 +1,50 @@
> +#include <stddef.h>
> +#include <asm/byteorder.h>
> +#include <asm/setup.h>
> +#include <fdt.h>
> +#include <libfdt.h>
> +
> +
> +int dt_setprop(void *fdt, const char *node_path, const char *property,
> +               uint32_t *val_array, int size)
> +{
> +	int offset;
> +
> +	offset = fdt_path_offset(fdt, node_path);
> +	if (offset < 0)
> +		return offset;
> +
> +	return fdt_setprop(fdt, offset, property, val_array, size);
> +}
> +
> +int dt_setprop_string(void *fdt, const char *node_path,
> +                      const char *property, const char *string)
> +{
> +	int offset;
> +		
> +	offset = fdt_path_offset(fdt, node_path);
> +	if (offset < 0)
> +		return offset;
> +			
> +	return fdt_setprop_string(fdt, offset, property, string);
> +}
> +
> +void dt_merge_atags(void *dt,  void *ataglist)
> +{
> +	struct tag *atag = ataglist;
> +	uint32_t mem_reg_property[2];
> +
> +	while (atag && atag->hdr.tag != 0) {
> +		if (atag->hdr.tag == ATAG_CMDLINE) {
> +			dt_setprop_string(dt, "/chosen", "bootargs",
> +			                  atag->u.cmdline.cmdline);
> +		} else if (atag->hdr.tag == ATAG_MEM) {
> +			mem_reg_property[0] = cpu_to_fdt32(atag->u.mem.start);
> +			mem_reg_property[1] = cpu_to_fdt32(atag->u.mem.size);
> +			dt_setprop(dt, "/memory", "reg", mem_reg_property,
> +			           sizeof(mem_reg_property));
> +		}
> +		atag = tag_next(atag);
> +	}
> +}
> +
> diff --git a/arch/arm/boot/compressed/head.S b/arch/arm/boot/compressed/head.S
> index db860b3..09e659d 100644
> --- a/arch/arm/boot/compressed/head.S
> +++ b/arch/arm/boot/compressed/head.S
> @@ -257,6 +257,13 @@ not_relocated:
>  		cmp	r1, r9
>  		bne	keep_atags
>  
> +		/* Merge some of the atags into the device tree */
> +		push	{r2, r3, r10, r11}
> +		mov	r0, r2
> +		mov	r1, r8
> +		bl	dt_merge_atags
> +		pop	{r2, r3, r10, r11}
> +
>  		/* copy the device tree binary to 0x0 */
>  		ldr	r9, [r10, #4]	@ device tree size
>  
> diff --git a/arch/arm/boot/compressed/misc.c b/arch/arm/boot/compressed/misc.c
> index e653a6d..2d4da4c 100644
> --- a/arch/arm/boot/compressed/misc.c
> +++ b/arch/arm/boot/compressed/misc.c
> @@ -29,7 +29,7 @@ unsigned int __machine_arch_type;
>  #include <asm/unaligned.h>
>  
>  
> -static void putstr(const char *ptr);
> +void putstr(const char *ptr);
>  extern void error(char *x);
>  
>  #include <mach/uncompress.h>
> @@ -100,7 +100,7 @@ static void icedcc_putc(int ch)
>  #define putc(ch)	icedcc_putc(ch)
>  #endif
>  
> -static void putstr(const char *ptr)
> +void putstr(const char *ptr)
>  {
>  	char c;
>  
> @@ -114,6 +114,60 @@ static void putstr(const char *ptr)
>  }
>  
>  
> +#ifdef CONFIG_ARM_APPENDED_DTB
> +/**
> + * strlen - Find the length of a string
> + * @s: The string to be sized
> + */
> +size_t strlen(const char *s)
> +{
> +        const char *sc;
> +
> +        for (sc = s; *sc != '\0'; ++sc)
> +                /* nothing */;
> +        return sc - s;
> +}
> +
> +/**
> + * strcmp - Compare two strings
> + * @cs: One string
> + * @ct: Another string
> + */
> +#undef strcmp
> +int strcmp(const char *cs, const char *ct)
> +{
> +	unsigned char c1, c2;
> +
> +	while (1) {
> +		c1 = *cs++;
> +		c2 = *ct++;
> +		if (c1 != c2)
> +			return c1 < c2 ? -1 : 1;
> +		if (!c1)
> +			break;
> +	}
> +	return 0;
> +}
> +
> +/**
> + * memcmp - Compare two areas of memory
> + * @cs: One area of memory
> + * @ct: Another area of memory
> + * @count: The size of the area.
> + */
> +#undef memcmp
> +int memcmp(const void *cs, const void *ct, size_t count)
> +{
> +	const unsigned char *su1, *su2;
> +	int res = 0;
> +
> +	for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
> +		if ((res = *su1 - *su2) != 0)
> +			break;
> +	return res;
> +}
> +#endif
> +
>  void *memcpy(void *__dest, __const void *__src, size_t __n)
>  {
>  	int i = 0;
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> 

[RFC 2/2] ARM:boot:device tree: Merge specific atags into the device tree

[Grant Likely]

On Feb 3, 2011 9:44 PM, "Nicolas Pitre" <nico@fluxnic.net> wrote:
>
> On Wed, 26 Jan 2011, John Bonesio wrote:
>
> > This patch is to merge in key atags into the appended device tree.  An
appended
> > device tree is where the zImage has a dtb binary appended at the end of
it. The
> > boot code looks for an appended device tree, then looks for a few key
atags
> > passed in by the bootloader.
> >
> > The bootargs and memory size settings, if they exist, override existing
values
> > in the appended device tree. If these values don't currently exist in
the
> > appended device tree, they are added.
> >
> > Signed-off-by: John Bonesio <bones@secretlab.ca>
> > Acked-by: Grant Likely <grant.likely@secretlab.ca>
>
> This is just for testing/evaluation purpose and not intended to be
> merged upstream at some point, right?

Correct.

>
> > ---
> >
> >  arch/arm/boot/compressed/Makefile |   31 +++++++++++++++++---
> >  arch/arm/boot/compressed/atags.c  |   50
++++++++++++++++++++++++++++++++
> >  arch/arm/boot/compressed/head.S   |    7 ++++
> >  arch/arm/boot/compressed/misc.c   |   58
++++++++++++++++++++++++++++++++++++-
> >  4 files changed, 139 insertions(+), 7 deletions(-)
> >  create mode 100644 arch/arm/boot/compressed/atags.c
> >
> > diff --git a/arch/arm/boot/compressed/Makefile
b/arch/arm/boot/compressed/Makefile
> > index 0a8f748..7978a39 100644
> > --- a/arch/arm/boot/compressed/Makefile
> > +++ b/arch/arm/boot/compressed/Makefile
> > @@ -49,6 +49,10 @@ ifeq ($(CONFIG_ARCH_SHMOBILE),y)
> >  OBJS         += head-shmobile.o
> >  endif
> >
> > +ifeq ($(CONFIG_ARM_APPENDED_DTB),y)
> > +OBJS         += atags.o libfdt.a
> > +endif
> > +
> >  #
> >  # We now have a PIC decompressor implementation.  Decompressors running
> >  # from RAM should not define ZTEXTADDR.  Decompressors running directly
> > @@ -80,7 +84,9 @@ ORIG_CFLAGS := $(KBUILD_CFLAGS)
> >  KBUILD_CFLAGS = $(subst -pg, , $(ORIG_CFLAGS))
> >  endif
> >
> > -EXTRA_CFLAGS  := -fpic -fno-builtin
> > +fdttree      := $(srctree)/scripts/dtc/libfdt
> > +
> > +EXTRA_CFLAGS  := -fpic -fno-builtin -I$(fdttree) -I$(obj)
> >  EXTRA_AFLAGS  := -Wa,-march=all
> >
> >  # Supply ZRELADDR to the decompressor via a linker symbol.
> > @@ -100,13 +106,28 @@ LDFLAGS_vmlinux += -X
> >  LDFLAGS_vmlinux += -T
> >
> >  # For __aeabi_uidivmod
> > -lib1funcs = $(obj)/lib1funcs.o
> > +libfuncs = $(obj)/lib1funcs.o
> >
> > -$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
> > -     $(call cmd,shipped)
> > +ifeq ($(CONFIG_ARM_APPENDED_DTB),y)
> > +# For memchr, memmove, etc
> > +libfuncs += $(obj)/memchr.o $(obj)/strchr.o $(obj)/memmove.o
$(obj)/memzero.o
> > +endif
> > +
> > +
> > +libfdtheader := $(fdttree)/fdt.h $(fdttree)/libfdt.h
$(fdttree)/libfdt_internal.h
> > +libfdtobj    := $(obj)/fdt.o $(obj)/fdt_ro.o $(obj)/fdt_wip.o
$(obj)/fdt_sw.o $(obj)/fdt_rw.o $(obj)/fdt_strerror.o
> > +
> > +$(libfdtobj): $(obj)/%.o: $(srctree)/scripts/dtc/libfdt/%.c
$(libfdtheader)
> > +     $(call cmd_cc_o_c)
> > +
> > +$(obj)/libfdt.a: $(libfdtobj)
> > +     $(AR) rcs $@ $^
> > +
> > +$(libfuncs): $(obj)/%.o: $(srctree)/arch/$(SRCARCH)/lib/%.S
> > +     $(call cmd_as_o_S)
> >
> >  $(obj)/vmlinux: $(obj)/vmlinux.lds $(obj)/$(HEAD)
$(obj)/piggy.$(suffix_y).o \
> > -             $(addprefix $(obj)/, $(OBJS)) $(lib1funcs) FORCE
> > +             $(addprefix $(obj)/, $(OBJS)) $(libfuncs) FORCE
> >       $(call if_changed,ld)
> >       @:
> >
> > diff --git a/arch/arm/boot/compressed/atags.c
b/arch/arm/boot/compressed/atags.c
> > new file mode 100644
> > index 0000000..e37d8de
> > --- /dev/null
> > +++ b/arch/arm/boot/compressed/atags.c
> > @@ -0,0 +1,50 @@
> > +#include <stddef.h>
> > +#include <asm/byteorder.h>
> > +#include <asm/setup.h>
> > +#include <fdt.h>
> > +#include <libfdt.h>
> > +
> > +
> > +int dt_setprop(void *fdt, const char *node_path, const char *property,
> > +               uint32_t *val_array, int size)
> > +{
> > +     int offset;
> > +
> > +     offset = fdt_path_offset(fdt, node_path);
> > +     if (offset < 0)
> > +             return offset;
> > +
> > +     return fdt_setprop(fdt, offset, property, val_array, size);
> > +}
> > +
> > +int dt_setprop_string(void *fdt, const char *node_path,
> > +                      const char *property, const char *string)
> > +{
> > +     int offset;
> > +
> > +     offset = fdt_path_offset(fdt, node_path);
> > +     if (offset < 0)
> > +             return offset;
> > +
> > +     return fdt_setprop_string(fdt, offset, property, string);
> > +}
> > +
> > +void dt_merge_atags(void *dt,  void *ataglist)
> > +{
> > +     struct tag *atag = ataglist;
> > +     uint32_t mem_reg_property[2];
> > +
> > +     while (atag && atag->hdr.tag != 0) {
> > +             if (atag->hdr.tag == ATAG_CMDLINE) {
> > +                     dt_setprop_string(dt, "/chosen", "bootargs",
> > +                                       atag->u.cmdline.cmdline);
> > +             } else if (atag->hdr.tag == ATAG_MEM) {
> > +                     mem_reg_property[0] =
cpu_to_fdt32(atag->u.mem.start);
> > +                     mem_reg_property[1] =
cpu_to_fdt32(atag->u.mem.size);
> > +                     dt_setprop(dt, "/memory", "reg", mem_reg_property,
> > +                                sizeof(mem_reg_property));
> > +             }
> > +             atag = tag_next(atag);
> > +     }
> > +}
> > +
> > diff --git a/arch/arm/boot/compressed/head.S
b/arch/arm/boot/compressed/head.S
> > index db860b3..09e659d 100644
> > --- a/arch/arm/boot/compressed/head.S
> > +++ b/arch/arm/boot/compressed/head.S
> > @@ -257,6 +257,13 @@ not_relocated:
> >               cmp     r1, r9
> >               bne     keep_atags
> >
> > +             /* Merge some of the atags into the device tree */
> > +             push    {r2, r3, r10, r11}
> > +             mov     r0, r2
> > +             mov     r1, r8
> > +             bl      dt_merge_atags
> > +             pop     {r2, r3, r10, r11}
> > +
> >               /* copy the device tree binary to 0x0 */
> >               ldr     r9, [r10, #4]   @ device tree size
> >
> > diff --git a/arch/arm/boot/compressed/misc.c
b/arch/arm/boot/compressed/misc.c
> > index e653a6d..2d4da4c 100644
> > --- a/arch/arm/boot/compressed/misc.c
> > +++ b/arch/arm/boot/compressed/misc.c
> > @@ -29,7 +29,7 @@ unsigned int __machine_arch_type;
> >  #include <asm/unaligned.h>
> >
> >
> > -static void putstr(const char *ptr);
> > +void putstr(const char *ptr);
> >  extern void error(char *x);
> >
> >  #include <mach/uncompress.h>
> > @@ -100,7 +100,7 @@ static void icedcc_putc(int ch)
> >  #define putc(ch)     icedcc_putc(ch)
> >  #endif
> >
> > -static void putstr(const char *ptr)
> > +void putstr(const char *ptr)
> >  {
> >       char c;
> >
> > @@ -114,6 +114,60 @@ static void putstr(const char *ptr)
> >  }
> >
> >
> > +#ifdef CONFIG_ARM_APPENDED_DTB
> > +/**
> > + * strlen - Find the length of a string
> > + * @s: The string to be sized
> > + */
> > +size_t strlen(const char *s)
> > +{
> > +        const char *sc;
> > +
> > +        for (sc = s; *sc != '\0'; ++sc)
> > +                /* nothing */;
> > +        return sc - s;
> > +}
> > +
> > +/**
> > + * strcmp - Compare two strings
> > + * @cs: One string
> > + * @ct: Another string
> > + */
> > +#undef strcmp
> > +int strcmp(const char *cs, const char *ct)
> > +{
> > +     unsigned char c1, c2;
> > +
> > +     while (1) {
> > +             c1 = *cs++;
> > +             c2 = *ct++;
> > +             if (c1 != c2)
> > +                     return c1 < c2 ? -1 : 1;
> > +             if (!c1)
> > +                     break;
> > +     }
> > +     return 0;
> > +}
> > +
> > +/**
> > + * memcmp - Compare two areas of memory
> > + * @cs: One area of memory
> > + * @ct: Another area of memory
> > + * @count: The size of the area.
> > + */
> > +#undef memcmp
> > +int memcmp(const void *cs, const void *ct, size_t count)
> > +{
> > +     const unsigned char *su1, *su2;
> > +     int res = 0;
> > +
> > +     for (su1 = cs, su2 = ct; 0 < count; ++su1, ++su2, count--)
> > +             if ((res = *su1 - *su2) != 0)
> > +                     break;
> > +     return res;
> > +}
> > +#endif
> > +
> >  void *memcpy(void *__dest, __const void *__src, size_t __n)
> >  {
> >       int i = 0;
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel at lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
> >
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