[PATCH] Implement the -a option to pad dtb aligned

[PATCH] Implement the -a option to pad dtb aligned

[Tim Wang]

There is one condition that need cat the dtb files
into one dtb.img which can support several boards
use same SoC platform.

And the original dtb file size is not aligned to any base.
This may cause "Synchronous Abort" when load from a unligned
address on some SoC machine, such as ARM.

So this patch implement the -a <aligned number> option to
pad zero at the end of dtb files and make the dtb size aligned
to <aligned number>.

Then, the aligned dtbs can cat together and load without "Synchronous
Abort".

Signed-off-by: Tim Wang <timwang@asrmicro.com>
---
 dtc.c      |  9 ++++++++-
 dtc.h      |  1 +
 flattree.c | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/dtc.c b/dtc.c
index 5fa23c4..1749d26 100644
--- a/dtc.c
+++ b/dtc.c
@@ -30,6 +30,7 @@ int quiet;		/* Level of quietness */
 int reservenum;		/* Number of memory reservation slots */
 int minsize;		/* Minimum blob size */
 int padsize;		/* Additional padding to blob */
+int align_size;		/* Additional padding to blob accroding to the align size */
 int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
 
 static void fill_fullpaths(struct node *tree, const char *prefix)
@@ -53,7 +54,7 @@ static void fill_fullpaths(struct node *tree, const char *prefix)
 #define FDT_VERSION(version)	_FDT_VERSION(version)
 #define _FDT_VERSION(version)	#version
 static const char usage_synopsis[] = "dtc [options] <input file>";
-static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv";
+static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:hv";
 static struct option const usage_long_opts[] = {
 	{"quiet",            no_argument, NULL, 'q'},
 	{"in-format",         a_argument, NULL, 'I'},
@@ -64,6 +65,7 @@ static struct option const usage_long_opts[] = {
 	{"reserve",           a_argument, NULL, 'R'},
 	{"space",             a_argument, NULL, 'S'},
 	{"pad",               a_argument, NULL, 'p'},
+	{"align",             a_argument, NULL, 'a'},
 	{"boot-cpu",          a_argument, NULL, 'b'},
 	{"force",            no_argument, NULL, 'f'},
 	{"include",           a_argument, NULL, 'i'},
@@ -91,6 +93,7 @@ static const char * const usage_opts_help[] = {
 	"\n\tMake space for <number> reserve map entries (for dtb and asm output)",
 	"\n\tMake the blob at least <bytes> long (extra space)",
 	"\n\tAdd padding to the blob of <bytes> long (extra space)",
+	"\n\tMake the blob align to the <bytes> (extra space)",
 	"\n\tSet the physical boot cpu",
 	"\n\tTry to produce output even if the input tree has errors",
 	"\n\tAdd a path to search for include files",
@@ -169,6 +172,7 @@ int main(int argc, char *argv[])
 	reservenum = 0;
 	minsize    = 0;
 	padsize    = 0;
+	align_size = 0;
 
 	while ((opt = util_getopt_long()) != EOF) {
 		switch (opt) {
@@ -196,6 +200,9 @@ int main(int argc, char *argv[])
 		case 'p':
 			padsize = strtol(optarg, NULL, 0);
 			break;
+		case 'a':
+			align_size = strtol(optarg, NULL, 0);
+			break;
 		case 'f':
 			force = true;
 			break;
diff --git a/dtc.h b/dtc.h
index 56212c8..b406d21 100644
--- a/dtc.h
+++ b/dtc.h
@@ -53,6 +53,7 @@ extern int quiet;		/* Level of quietness */
 extern int reservenum;		/* Number of memory reservation slots */
 extern int minsize;		/* Minimum blob size */
 extern int padsize;		/* Additional padding to blob */
+extern int align_size;		/* Additional padding to blob accroding to the align size */
 extern int phandle_format;	/* Use linux,phandle or phandle properties */
 
 #define PHANDLE_LEGACY	0x1
diff --git a/flattree.c b/flattree.c
index ec14954..733e32e 100644
--- a/flattree.c
+++ b/flattree.c
@@ -413,6 +413,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
 		fdt.totalsize = cpu_to_fdt32(tsize);
 	}
 
+	if (align_size > 0) {
+		int tsize = fdt32_to_cpu(fdt.totalsize);
+		padlen += (align_size - tsize % align_size);
+		tsize += padlen;
+		fdt.totalsize = cpu_to_fdt32(tsize);
+	}
+
 	/*
 	 * Assemble the blob: start with the header, add with alignment
 	 * the reserve buffer, add the reserve map terminating zeroes,
@@ -572,6 +579,9 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version)
 	if (padsize > 0) {
 		fprintf(f, "\t.space\t%d, 0\n", padsize);
 	}
+	if (align_size > 0) {
+		fprintf(f, "\t.space\t%d, 0\n", align_size);
+	}
 	emit_label(f, symprefix, "blob_abs_end");
 
 	data_free(strbuf);
-- 
1.9.1

[PATCH] Implement the -a option to pad dtb aligned

[Tim Wang]

There is one condition that need cat the dtb files
into one dtb.img which can support several boards
use same SoC platform.

And the original dtb file size is not aligned to any base.
This may cause "Synchronous Abort" when load from a unligned
address on some SoC machine, such as ARM.

So this patch implement the -a <aligned number> option to
pad zero at the end of dtb files and make the dtb size aligned
to <aligned number>.

Then, the aligned dtbs can cat together and load without "Synchronous
Abort".

Signed-off-by: Tim Wang <timwang-XOWFcpiLszpWk0Htik3J/w@public.gmane.org>
---
 dtc.c      |  9 ++++++++-
 dtc.h      |  1 +
 flattree.c | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/dtc.c b/dtc.c
index 5fa23c4..1749d26 100644
--- a/dtc.c
+++ b/dtc.c
@@ -30,6 +30,7 @@ int quiet;		/* Level of quietness */
 int reservenum;		/* Number of memory reservation slots */
 int minsize;		/* Minimum blob size */
 int padsize;		/* Additional padding to blob */
+int align_size;		/* Additional padding to blob accroding to the align size */
 int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
 
 static void fill_fullpaths(struct node *tree, const char *prefix)
@@ -53,7 +54,7 @@ static void fill_fullpaths(struct node *tree, const char *prefix)
 #define FDT_VERSION(version)	_FDT_VERSION(version)
 #define _FDT_VERSION(version)	#version
 static const char usage_synopsis[] = "dtc [options] <input file>";
-static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv";
+static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:hv";
 static struct option const usage_long_opts[] = {
 	{"quiet",            no_argument, NULL, 'q'},
 	{"in-format",         a_argument, NULL, 'I'},
@@ -64,6 +65,7 @@ static struct option const usage_long_opts[] = {
 	{"reserve",           a_argument, NULL, 'R'},
 	{"space",             a_argument, NULL, 'S'},
 	{"pad",               a_argument, NULL, 'p'},
+	{"align",             a_argument, NULL, 'a'},
 	{"boot-cpu",          a_argument, NULL, 'b'},
 	{"force",            no_argument, NULL, 'f'},
 	{"include",           a_argument, NULL, 'i'},
@@ -91,6 +93,7 @@ static const char * const usage_opts_help[] = {
 	"\n\tMake space for <number> reserve map entries (for dtb and asm output)",
 	"\n\tMake the blob at least <bytes> long (extra space)",
 	"\n\tAdd padding to the blob of <bytes> long (extra space)",
+	"\n\tMake the blob align to the <bytes> (extra space)",
 	"\n\tSet the physical boot cpu",
 	"\n\tTry to produce output even if the input tree has errors",
 	"\n\tAdd a path to search for include files",
@@ -169,6 +172,7 @@ int main(int argc, char *argv[])
 	reservenum = 0;
 	minsize    = 0;
 	padsize    = 0;
+	align_size = 0;
 
 	while ((opt = util_getopt_long()) != EOF) {
 		switch (opt) {
@@ -196,6 +200,9 @@ int main(int argc, char *argv[])
 		case 'p':
 			padsize = strtol(optarg, NULL, 0);
 			break;
+		case 'a':
+			align_size = strtol(optarg, NULL, 0);
+			break;
 		case 'f':
 			force = true;
 			break;
diff --git a/dtc.h b/dtc.h
index 56212c8..b406d21 100644
--- a/dtc.h
+++ b/dtc.h
@@ -53,6 +53,7 @@ extern int quiet;		/* Level of quietness */
 extern int reservenum;		/* Number of memory reservation slots */
 extern int minsize;		/* Minimum blob size */
 extern int padsize;		/* Additional padding to blob */
+extern int align_size;		/* Additional padding to blob accroding to the align size */
 extern int phandle_format;	/* Use linux,phandle or phandle properties */
 
 #define PHANDLE_LEGACY	0x1
diff --git a/flattree.c b/flattree.c
index ec14954..733e32e 100644
--- a/flattree.c
+++ b/flattree.c
@@ -413,6 +413,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
 		fdt.totalsize = cpu_to_fdt32(tsize);
 	}
 
+	if (align_size > 0) {
+		int tsize = fdt32_to_cpu(fdt.totalsize);
+		padlen += (align_size - tsize % align_size);
+		tsize += padlen;
+		fdt.totalsize = cpu_to_fdt32(tsize);
+	}
+
 	/*
 	 * Assemble the blob: start with the header, add with alignment
 	 * the reserve buffer, add the reserve map terminating zeroes,
@@ -572,6 +579,9 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version)
 	if (padsize > 0) {
 		fprintf(f, "\t.space\t%d, 0\n", padsize);
 	}
+	if (align_size > 0) {
+		fprintf(f, "\t.space\t%d, 0\n", align_size);
+	}
 	emit_label(f, symprefix, "blob_abs_end");
 
 	data_free(strbuf);
-- 
1.9.1


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Re: [PATCH] Implement the -a option to pad dtb aligned

[Frank Rowand]

Hi Tim,

On 06/24/16 04:19, Tim Wang wrote:
> There is one condition that need cat the dtb files
> into one dtb.img which can support several boards
> use same SoC platform.
> 
> And the original dtb file size is not aligned to any base.
> This may cause "Synchronous Abort" when load from a unligned
> address on some SoC machine, such as ARM.
> 
> So this patch implement the -a <aligned number> option to
> pad zero at the end of dtb files and make the dtb size aligned
> to <aligned number>.
> 
> Then, the aligned dtbs can cat together and load without "Synchronous
> Abort".
> 
> Signed-off-by: Tim Wang <timwang@asrmicro.com>
> ---
>  dtc.c      |  9 ++++++++-
>  dtc.h      |  1 +
>  flattree.c | 10 ++++++++++

[ ... ]

The MAINTAINERS file is not very helpful in this case.
You need to send dtc patches to the devicetree-compiler list

  devicetree-compiler@vger.kernel.org

Subscription info is at

  http://vger.kernel.org/vger-lists.html#devicetree-compiler

After changes are made by the dtc maintainer, we pull the new
version of dtc into the Linux tree.

-Frank

Re: [PATCH] Implement the -a option to pad dtb aligned

[Frank Rowand]

Hi Tim,

On 06/24/16 04:19, Tim Wang wrote:
> There is one condition that need cat the dtb files
> into one dtb.img which can support several boards
> use same SoC platform.
> 
> And the original dtb file size is not aligned to any base.
> This may cause "Synchronous Abort" when load from a unligned
> address on some SoC machine, such as ARM.
> 
> So this patch implement the -a <aligned number> option to
> pad zero at the end of dtb files and make the dtb size aligned
> to <aligned number>.
> 
> Then, the aligned dtbs can cat together and load without "Synchronous
> Abort".
> 
> Signed-off-by: Tim Wang <timwang-XOWFcpiLszpWk0Htik3J/w@public.gmane.org>
> ---
>  dtc.c      |  9 ++++++++-
>  dtc.h      |  1 +
>  flattree.c | 10 ++++++++++

[ ... ]

The MAINTAINERS file is not very helpful in this case.
You need to send dtc patches to the devicetree-compiler list

  devicetree-compiler-u79uwXL29TY76Z2rM5mHXA@public.gmane.org

Subscription info is at

  http://vger.kernel.org/vger-lists.html#devicetree-compiler

After changes are made by the dtc maintainer, we pull the new
version of dtc into the Linux tree.

-Frank
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Re: [PATCH] Implement the -a option to pad dtb aligned

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 7176 bytes --]

On Mon, Jun 27, 2016 at 08:49:37AM +0000, Wang Tim（王艇艇） wrote:
> Hi David,
> (Seems my pervious mail rejected by vger.kernel.org).
> 
> Thanks for your kindly review!
> About the usage of this patch, as I know,
> some android phone and google TV soc vendors or production vendors
> need such option to cat all dtb files to support several products.
> Such as one soc vendor support two customers products. And each of
> them use different screen panel and camera sensor. But most other peripherals
> are same as the common board.
> We can use one kernel Image and several dtb files to support both of them.

Right, I see why you need the alignment in the output.  But it's
pretty easy to introduce this as you produce the archive, without
folding it into dtc.

For example:
	$ dd if=1.dtb bs=8 conv=sync of=dtbset
	$ dd if=2.dtb bs=8 conv=sync,notrunc oflag=append of=dtbset
	$ dd if=3.dtb bs=8 conv=sync,notrunc oflag=append of=dtbset
		.
		.
		.

Will create dtbset with all the dtbs aligned to 8 byte boundaries.

> The calculate method of -a option after -p/-S is totally wrong.
> I've fix it in attached patch file, please help to review again.
> 
> But I'm not sure whether my dt_to_asm part change is right.
> Please show me more details if my patch is wrong again.
> 
> Here is the updated patch：
> [PATCH] Implement the -a option to pad dtb aligned
> 
> There is one condition that need cat the dtb files
> into one dtb.img which can support several boards
> use same SoC platform.
> 
> And the original dtb file size is not aligned to any base.
> This may cause "Synchronous Abort" when load from a unligned
> address on some SoC machine, such as ARM.
> 
> So this patch implement the -a <aligned number> option to
> pad zero at the end of dtb files and make the dtb size aligned
> to <aligned number>.
> 
> Then, the aligned dtbs can cat together and load without "Synchronous
> Abort".
> 
> Signed-off-by: Tim Wang <timwang-XOWFcpiLszpWk0Htik3J/w@public.gmane.org>
> ---
>  dtc.c      |  9 ++++++++-
>  dtc.h      |  1 +
>  flattree.c | 13 ++++++++++++-
>  3 files changed, 21 insertions(+), 2 deletions(-)
> 
> diff --git a/dtc.c b/dtc.c
> index 5fa23c4..1749d26 100644
> --- a/dtc.c
> +++ b/dtc.c
> @@ -30,6 +30,7 @@ int quiet;		/* Level of quietness */
>  int reservenum;		/* Number of memory reservation slots */
>  int minsize;		/* Minimum blob size */
>  int padsize;		/* Additional padding to blob */
> +int align_size;		/* Additional padding to blob accroding to the align size */
>  int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
>  
>  static void fill_fullpaths(struct node *tree, const char *prefix)
> @@ -53,7 +54,7 @@ static void fill_fullpaths(struct node *tree, const char *prefix)
>  #define FDT_VERSION(version)	_FDT_VERSION(version)
>  #define _FDT_VERSION(version)	#version
>  static const char usage_synopsis[] = "dtc [options] <input file>";
> -static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv";
> +static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:hv";
>  static struct option const usage_long_opts[] = {
>  	{"quiet",            no_argument, NULL, 'q'},
>  	{"in-format",         a_argument, NULL, 'I'},
> @@ -64,6 +65,7 @@ static struct option const usage_long_opts[] = {
>  	{"reserve",           a_argument, NULL, 'R'},
>  	{"space",             a_argument, NULL, 'S'},
>  	{"pad",               a_argument, NULL, 'p'},
> +	{"align",             a_argument, NULL, 'a'},
>  	{"boot-cpu",          a_argument, NULL, 'b'},
>  	{"force",            no_argument, NULL, 'f'},
>  	{"include",           a_argument, NULL, 'i'},
> @@ -91,6 +93,7 @@ static const char * const usage_opts_help[] = {
>  	"\n\tMake space for <number> reserve map entries (for dtb and asm output)",
>  	"\n\tMake the blob at least <bytes> long (extra space)",
>  	"\n\tAdd padding to the blob of <bytes> long (extra space)",
> +	"\n\tMake the blob align to the <bytes> (extra space)",
>  	"\n\tSet the physical boot cpu",
>  	"\n\tTry to produce output even if the input tree has errors",
>  	"\n\tAdd a path to search for include files",
> @@ -169,6 +172,7 @@ int main(int argc, char *argv[])
>  	reservenum = 0;
>  	minsize    = 0;
>  	padsize    = 0;
> +	align_size = 0;
>  
>  	while ((opt = util_getopt_long()) != EOF) {
>  		switch (opt) {
> @@ -196,6 +200,9 @@ int main(int argc, char *argv[])
>  		case 'p':
>  			padsize = strtol(optarg, NULL, 0);
>  			break;
> +		case 'a':
> +			align_size = strtol(optarg, NULL, 0);
> +			break;
>  		case 'f':
>  			force = true;
>  			break;
> diff --git a/dtc.h b/dtc.h
> index 56212c8..b406d21 100644
> --- a/dtc.h
> +++ b/dtc.h
> @@ -53,6 +53,7 @@ extern int quiet;		/* Level of quietness */
>  extern int reservenum;		/* Number of memory reservation slots */
>  extern int minsize;		/* Minimum blob size */
>  extern int padsize;		/* Additional padding to blob */
> +extern int align_size;		/* Additional padding to blob accroding to the align size */
>  extern int phandle_format;	/* Use linux,phandle or phandle properties */
>  
>  #define PHANDLE_LEGACY	0x1
> diff --git a/flattree.c b/flattree.c
> index ec14954..29f0a54 100644
> --- a/flattree.c
> +++ b/flattree.c
> @@ -398,10 +398,12 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
>  	 */
>  	if (minsize > 0) {
>  		padlen = minsize - fdt32_to_cpu(fdt.totalsize);
> -		if ((padlen < 0) && (quiet < 1))
> +		if ((padlen < 0) && (quiet < 1)) {
>  			fprintf(stderr,
>  				"Warning: blob size %d >= minimum size %d\n",
>  				fdt32_to_cpu(fdt.totalsize), minsize);
> +			padlen = 0;
> +		}
>  	}
>  
>  	if (padsize > 0)
> @@ -413,6 +415,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
>  		fdt.totalsize = cpu_to_fdt32(tsize);
>  	}
>  
> +	if (align_size > 0) {
> +		int tsize = fdt32_to_cpu(fdt.totalsize);
> +		padlen += ALIGN(tsize, align_size) - tsize;
> +		tsize = ALIGN(tsize, align_size);
> +		fdt.totalsize = cpu_to_fdt32(tsize);
> +	}
> +

This is still wrong.  The previous if already increased totalsize by
padlen.  Now you've adjusted padlen and added it to totalsize again.

Please, actually test this with both -p and -a options.

>  	/*
>  	 * Assemble the blob: start with the header, add with alignment
>  	 * the reserve buffer, add the reserve map terminating zeroes,
> @@ -478,6 +487,8 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version)
>  	fprintf(f, "/* autogenerated by dtc, do not edit */\n\n");
>  
>  	emit_label(f, symprefix, "blob_start");
> +	if (align_size > 0)
> +		asm_emit_align(f, align_size);

This is correct, as long as align_size is a power of two - otherwise
it will probably cause an assembler error.

>  	emit_label(f, symprefix, "header");
>  	fprintf(f, "\t/* magic */\n");
>  	asm_emit_cell(f, FDT_MAGIC);

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

RE: [PATCH] Implement the -a option to pad dtb aligned

[Wang Tim（王艇艇）]

Hi David,
(Seems my pervious mail rejected by vger.kernel.org).

Thanks for your kindly review!
About the usage of this patch, as I know,
some android phone and google TV soc vendors or production vendors
need such option to cat all dtb files to support several products.
Such as one soc vendor support two customers products. And each of
them use different screen panel and camera sensor. But most other peripherals
are same as the common board.
We can use one kernel Image and several dtb files to support both of them.

The calculate method of -a option after -p/-S is totally wrong.
I've fix it in attached patch file, please help to review again.

But I'm not sure whether my dt_to_asm part change is right.
Please show me more details if my patch is wrong again.

Here is the updated patch：
[PATCH] Implement the -a option to pad dtb aligned

There is one condition that need cat the dtb files
into one dtb.img which can support several boards
use same SoC platform.

And the original dtb file size is not aligned to any base.
This may cause "Synchronous Abort" when load from a unligned
address on some SoC machine, such as ARM.

So this patch implement the -a <aligned number> option to
pad zero at the end of dtb files and make the dtb size aligned
to <aligned number>.

Then, the aligned dtbs can cat together and load without "Synchronous
Abort".

Signed-off-by: Tim Wang <timwang@asrmicro.com>
---
 dtc.c      |  9 ++++++++-
 dtc.h      |  1 +
 flattree.c | 13 ++++++++++++-
 3 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/dtc.c b/dtc.c
index 5fa23c4..1749d26 100644
--- a/dtc.c
+++ b/dtc.c
@@ -30,6 +30,7 @@ int quiet;		/* Level of quietness */
 int reservenum;		/* Number of memory reservation slots */
 int minsize;		/* Minimum blob size */
 int padsize;		/* Additional padding to blob */
+int align_size;		/* Additional padding to blob accroding to the align size */
 int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
 
 static void fill_fullpaths(struct node *tree, const char *prefix)
@@ -53,7 +54,7 @@ static void fill_fullpaths(struct node *tree, const char *prefix)
 #define FDT_VERSION(version)	_FDT_VERSION(version)
 #define _FDT_VERSION(version)	#version
 static const char usage_synopsis[] = "dtc [options] <input file>";
-static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv";
+static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:hv";
 static struct option const usage_long_opts[] = {
 	{"quiet",            no_argument, NULL, 'q'},
 	{"in-format",         a_argument, NULL, 'I'},
@@ -64,6 +65,7 @@ static struct option const usage_long_opts[] = {
 	{"reserve",           a_argument, NULL, 'R'},
 	{"space",             a_argument, NULL, 'S'},
 	{"pad",               a_argument, NULL, 'p'},
+	{"align",             a_argument, NULL, 'a'},
 	{"boot-cpu",          a_argument, NULL, 'b'},
 	{"force",            no_argument, NULL, 'f'},
 	{"include",           a_argument, NULL, 'i'},
@@ -91,6 +93,7 @@ static const char * const usage_opts_help[] = {
 	"\n\tMake space for <number> reserve map entries (for dtb and asm output)",
 	"\n\tMake the blob at least <bytes> long (extra space)",
 	"\n\tAdd padding to the blob of <bytes> long (extra space)",
+	"\n\tMake the blob align to the <bytes> (extra space)",
 	"\n\tSet the physical boot cpu",
 	"\n\tTry to produce output even if the input tree has errors",
 	"\n\tAdd a path to search for include files",
@@ -169,6 +172,7 @@ int main(int argc, char *argv[])
 	reservenum = 0;
 	minsize    = 0;
 	padsize    = 0;
+	align_size = 0;
 
 	while ((opt = util_getopt_long()) != EOF) {
 		switch (opt) {
@@ -196,6 +200,9 @@ int main(int argc, char *argv[])
 		case 'p':
 			padsize = strtol(optarg, NULL, 0);
 			break;
+		case 'a':
+			align_size = strtol(optarg, NULL, 0);
+			break;
 		case 'f':
 			force = true;
 			break;
diff --git a/dtc.h b/dtc.h
index 56212c8..b406d21 100644
--- a/dtc.h
+++ b/dtc.h
@@ -53,6 +53,7 @@ extern int quiet;		/* Level of quietness */
 extern int reservenum;		/* Number of memory reservation slots */
 extern int minsize;		/* Minimum blob size */
 extern int padsize;		/* Additional padding to blob */
+extern int align_size;		/* Additional padding to blob accroding to the align size */
 extern int phandle_format;	/* Use linux,phandle or phandle properties */
 
 #define PHANDLE_LEGACY	0x1
diff --git a/flattree.c b/flattree.c
index ec14954..29f0a54 100644
--- a/flattree.c
+++ b/flattree.c
@@ -398,10 +398,12 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
 	 */
 	if (minsize > 0) {
 		padlen = minsize - fdt32_to_cpu(fdt.totalsize);
-		if ((padlen < 0) && (quiet < 1))
+		if ((padlen < 0) && (quiet < 1)) {
 			fprintf(stderr,
 				"Warning: blob size %d >= minimum size %d\n",
 				fdt32_to_cpu(fdt.totalsize), minsize);
+			padlen = 0;
+		}
 	}
 
 	if (padsize > 0)
@@ -413,6 +415,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
 		fdt.totalsize = cpu_to_fdt32(tsize);
 	}
 
+	if (align_size > 0) {
+		int tsize = fdt32_to_cpu(fdt.totalsize);
+		padlen += ALIGN(tsize, align_size) - tsize;
+		tsize = ALIGN(tsize, align_size);
+		fdt.totalsize = cpu_to_fdt32(tsize);
+	}
+
 	/*
 	 * Assemble the blob: start with the header, add with alignment
 	 * the reserve buffer, add the reserve map terminating zeroes,
@@ -478,6 +487,8 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version)
 	fprintf(f, "/* autogenerated by dtc, do not edit */\n\n");
 
 	emit_label(f, symprefix, "blob_start");
+	if (align_size > 0)
+		asm_emit_align(f, align_size);
 	emit_label(f, symprefix, "header");
 	fprintf(f, "\t/* magic */\n");
 	asm_emit_cell(f, FDT_MAGIC);
-- 
1.9.1

Best Regards
Tim Wang(王艇艇)

-----Original Message-----
From: David Gibson [mailto:david@gibson.dropbear.id.au] 
Sent: Monday, June 27, 2016 1:45 PM
To: Wang Tim（王艇艇）
Cc: devicetree-compiler@vger.kernel.org; wtt_usst@163.com
Subject: Re: [PATCH] Implement the -a option to pad dtb aligned

On Sat, Jun 25, 2016 at 04:32:17AM +0800, Tim Wang wrote:
> There is one condition that need cat the dtb files into one dtb.img 
> which can support several boards use same SoC platform.
> 
> And the original dtb file size is not aligned to any base.
> This may cause "Synchronous Abort" when load from a unligned address 
> on some SoC machine, such as ARM.
> 
> So this patch implement the -a <aligned number> option to pad zero at 
> the end of dtb files and make the dtb size aligned to <aligned 
> number>.
> 
> Then, the aligned dtbs can cat together and load without "Synchronous 
> Abort".
> 
> Signed-off-by: Tim Wang <timwang@asrmicro.com>

I'm a little dubious about how widely useful this is, but I'd consider applying something to this effect.

However, this implementation is incorrect on multiple counts.

> ---
>  dtc.c      |  9 ++++++++-
>  dtc.h      |  1 +
>  flattree.c | 10 ++++++++++
>  3 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/dtc.c b/dtc.c
> index 5fa23c4..1749d26 100644
> --- a/dtc.c
> +++ b/dtc.c
> @@ -30,6 +30,7 @@ int quiet;		/* Level of quietness */
>  int reservenum;		/* Number of memory reservation slots */
>  int minsize;		/* Minimum blob size */
>  int padsize;		/* Additional padding to blob */
> +int align_size;		/* Additional padding to blob accroding to the align size */
>  int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
>  
>  static void fill_fullpaths(struct node *tree, const char *prefix) @@ 
> -53,7 +54,7 @@ static void fill_fullpaths(struct node *tree, const char *prefix)
>  #define FDT_VERSION(version)	_FDT_VERSION(version)
>  #define _FDT_VERSION(version)	#version
>  static const char usage_synopsis[] = "dtc [options] <input file>"; 
> -static const char usage_short_opts[] = 
> "qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv";
> +static const char usage_short_opts[] = 
> +"qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:hv";
>  static struct option const usage_long_opts[] = {
>  	{"quiet",            no_argument, NULL, 'q'},
>  	{"in-format",         a_argument, NULL, 'I'},
> @@ -64,6 +65,7 @@ static struct option const usage_long_opts[] = {
>  	{"reserve",           a_argument, NULL, 'R'},
>  	{"space",             a_argument, NULL, 'S'},
>  	{"pad",               a_argument, NULL, 'p'},
> +	{"align",             a_argument, NULL, 'a'},
>  	{"boot-cpu",          a_argument, NULL, 'b'},
>  	{"force",            no_argument, NULL, 'f'},
>  	{"include",           a_argument, NULL, 'i'},
> @@ -91,6 +93,7 @@ static const char * const usage_opts_help[] = {
>  	"\n\tMake space for <number> reserve map entries (for dtb and asm output)",
>  	"\n\tMake the blob at least <bytes> long (extra space)",
>  	"\n\tAdd padding to the blob of <bytes> long (extra space)",
> +	"\n\tMake the blob align to the <bytes> (extra space)",
>  	"\n\tSet the physical boot cpu",
>  	"\n\tTry to produce output even if the input tree has errors",
>  	"\n\tAdd a path to search for include files", @@ -169,6 +172,7 @@ 
> int main(int argc, char *argv[])
>  	reservenum = 0;
>  	minsize    = 0;
>  	padsize    = 0;
> +	align_size = 0;
>  
>  	while ((opt = util_getopt_long()) != EOF) {
>  		switch (opt) {
> @@ -196,6 +200,9 @@ int main(int argc, char *argv[])
>  		case 'p':
>  			padsize = strtol(optarg, NULL, 0);
>  			break;
> +		case 'a':
> +			align_size = strtol(optarg, NULL, 0);
> +			break;
>  		case 'f':
>  			force = true;
>  			break;
> diff --git a/dtc.h b/dtc.h
> index 56212c8..b406d21 100644
> --- a/dtc.h
> +++ b/dtc.h
> @@ -53,6 +53,7 @@ extern int quiet;		/* Level of quietness */
>  extern int reservenum;		/* Number of memory reservation slots */
>  extern int minsize;		/* Minimum blob size */
>  extern int padsize;		/* Additional padding to blob */
> +extern int align_size;		/* Additional padding to blob accroding to the align size */
>  extern int phandle_format;	/* Use linux,phandle or phandle properties */
>  
>  #define PHANDLE_LEGACY	0x1
> diff --git a/flattree.c b/flattree.c
> index ec14954..733e32e 100644
> --- a/flattree.c
> +++ b/flattree.c
> @@ -413,6 +413,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
>  		fdt.totalsize = cpu_to_fdt32(tsize);
>  	}
>  
> +	if (align_size > 0) {
> +		int tsize = fdt32_to_cpu(fdt.totalsize);
> +		padlen += (align_size - tsize % align_size);
> +		tsize += padlen;
> +		fdt.totalsize = cpu_to_fdt32(tsize);
> +	}

This occurs after totalsize has already been adjusted for the -p option.  So, if -p and -a are both specified, this will apply the -p padding twice.  Further if the -p value itself isn't aligned, neither will the final blob be.

Instead you want to adjust padlen for the alignment size *before* altering fdt.totalsize.

> +
>  	/*
>  	 * Assemble the blob: start with the header, add with alignment
>  	 * the reserve buffer, add the reserve map terminating zeroes, @@ 
> -572,6 +579,9 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version)
>  	if (padsize > 0) {
>  		fprintf(f, "\t.space\t%d, 0\n", padsize);
>  	}
> +	if (align_size > 0) {
> +		fprintf(f, "\t.space\t%d, 0\n", align_size);
> +	}

This is also just plain wrong.  This will simply add align_size bytes of extra padding, rather than aligning the final result.

You either want to adjust padsize to be aligned before emiting the .space padsize directive, or you want to use a .align directive instead.

This patch should also add one or more testcases, which might have caught the errors above.

>  	emit_label(f, symprefix, "blob_abs_end");
>  
>  	data_free(strbuf);

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: [PATCH] Implement the -a option to pad dtb aligned

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 5882 bytes --]

On Sat, Jun 25, 2016 at 04:32:17AM +0800, Tim Wang wrote:
> There is one condition that need cat the dtb files
> into one dtb.img which can support several boards
> use same SoC platform.
> 
> And the original dtb file size is not aligned to any base.
> This may cause "Synchronous Abort" when load from a unligned
> address on some SoC machine, such as ARM.
> 
> So this patch implement the -a <aligned number> option to
> pad zero at the end of dtb files and make the dtb size aligned
> to <aligned number>.
> 
> Then, the aligned dtbs can cat together and load without "Synchronous
> Abort".
> 
> Signed-off-by: Tim Wang <timwang-XOWFcpiLszpWk0Htik3J/w@public.gmane.org>

I'm a little dubious about how widely useful this is, but I'd consider
applying something to this effect.

However, this implementation is incorrect on multiple counts.

> ---
>  dtc.c      |  9 ++++++++-
>  dtc.h      |  1 +
>  flattree.c | 10 ++++++++++
>  3 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/dtc.c b/dtc.c
> index 5fa23c4..1749d26 100644
> --- a/dtc.c
> +++ b/dtc.c
> @@ -30,6 +30,7 @@ int quiet;		/* Level of quietness */
>  int reservenum;		/* Number of memory reservation slots */
>  int minsize;		/* Minimum blob size */
>  int padsize;		/* Additional padding to blob */
> +int align_size;		/* Additional padding to blob accroding to the align size */
>  int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
>  
>  static void fill_fullpaths(struct node *tree, const char *prefix)
> @@ -53,7 +54,7 @@ static void fill_fullpaths(struct node *tree, const char *prefix)
>  #define FDT_VERSION(version)	_FDT_VERSION(version)
>  #define _FDT_VERSION(version)	#version
>  static const char usage_synopsis[] = "dtc [options] <input file>";
> -static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv";
> +static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:hv";
>  static struct option const usage_long_opts[] = {
>  	{"quiet",            no_argument, NULL, 'q'},
>  	{"in-format",         a_argument, NULL, 'I'},
> @@ -64,6 +65,7 @@ static struct option const usage_long_opts[] = {
>  	{"reserve",           a_argument, NULL, 'R'},
>  	{"space",             a_argument, NULL, 'S'},
>  	{"pad",               a_argument, NULL, 'p'},
> +	{"align",             a_argument, NULL, 'a'},
>  	{"boot-cpu",          a_argument, NULL, 'b'},
>  	{"force",            no_argument, NULL, 'f'},
>  	{"include",           a_argument, NULL, 'i'},
> @@ -91,6 +93,7 @@ static const char * const usage_opts_help[] = {
>  	"\n\tMake space for <number> reserve map entries (for dtb and asm output)",
>  	"\n\tMake the blob at least <bytes> long (extra space)",
>  	"\n\tAdd padding to the blob of <bytes> long (extra space)",
> +	"\n\tMake the blob align to the <bytes> (extra space)",
>  	"\n\tSet the physical boot cpu",
>  	"\n\tTry to produce output even if the input tree has errors",
>  	"\n\tAdd a path to search for include files",
> @@ -169,6 +172,7 @@ int main(int argc, char *argv[])
>  	reservenum = 0;
>  	minsize    = 0;
>  	padsize    = 0;
> +	align_size = 0;
>  
>  	while ((opt = util_getopt_long()) != EOF) {
>  		switch (opt) {
> @@ -196,6 +200,9 @@ int main(int argc, char *argv[])
>  		case 'p':
>  			padsize = strtol(optarg, NULL, 0);
>  			break;
> +		case 'a':
> +			align_size = strtol(optarg, NULL, 0);
> +			break;
>  		case 'f':
>  			force = true;
>  			break;
> diff --git a/dtc.h b/dtc.h
> index 56212c8..b406d21 100644
> --- a/dtc.h
> +++ b/dtc.h
> @@ -53,6 +53,7 @@ extern int quiet;		/* Level of quietness */
>  extern int reservenum;		/* Number of memory reservation slots */
>  extern int minsize;		/* Minimum blob size */
>  extern int padsize;		/* Additional padding to blob */
> +extern int align_size;		/* Additional padding to blob accroding to the align size */
>  extern int phandle_format;	/* Use linux,phandle or phandle properties */
>  
>  #define PHANDLE_LEGACY	0x1
> diff --git a/flattree.c b/flattree.c
> index ec14954..733e32e 100644
> --- a/flattree.c
> +++ b/flattree.c
> @@ -413,6 +413,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
>  		fdt.totalsize = cpu_to_fdt32(tsize);
>  	}
>  
> +	if (align_size > 0) {
> +		int tsize = fdt32_to_cpu(fdt.totalsize);
> +		padlen += (align_size - tsize % align_size);
> +		tsize += padlen;
> +		fdt.totalsize = cpu_to_fdt32(tsize);
> +	}

This occurs after totalsize has already been adjusted for the -p
option.  So, if -p and -a are both specified, this will apply the -p
padding twice.  Further if the -p value itself isn't aligned, neither
will the final blob be.

Instead you want to adjust padlen for the alignment size *before*
altering fdt.totalsize.

> +
>  	/*
>  	 * Assemble the blob: start with the header, add with alignment
>  	 * the reserve buffer, add the reserve map terminating zeroes,
> @@ -572,6 +579,9 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version)
>  	if (padsize > 0) {
>  		fprintf(f, "\t.space\t%d, 0\n", padsize);
>  	}
> +	if (align_size > 0) {
> +		fprintf(f, "\t.space\t%d, 0\n", align_size);
> +	}

This is also just plain wrong.  This will simply add align_size bytes
of extra padding, rather than aligning the final result.

You either want to adjust padsize to be aligned before emiting the
.space padsize directive, or you want to use a .align directive
instead.

This patch should also add one or more testcases, which might have
caught the errors above.

>  	emit_label(f, symprefix, "blob_abs_end");
>  
>  	data_free(strbuf);

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 819 bytes --]

[PATCH] Implement the -a option to pad dtb aligned

[Tim Wang]

There is one condition that need cat the dtb files
into one dtb.img which can support several boards
use same SoC platform.

And the original dtb file size is not aligned to any base.
This may cause "Synchronous Abort" when load from a unligned
address on some SoC machine, such as ARM.

So this patch implement the -a <aligned number> option to
pad zero at the end of dtb files and make the dtb size aligned
to <aligned number>.

Then, the aligned dtbs can cat together and load without "Synchronous
Abort".

Signed-off-by: Tim Wang <timwang-XOWFcpiLszpWk0Htik3J/w@public.gmane.org>
---
 dtc.c      |  9 ++++++++-
 dtc.h      |  1 +
 flattree.c | 10 ++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/dtc.c b/dtc.c
index 5fa23c4..1749d26 100644
--- a/dtc.c
+++ b/dtc.c
@@ -30,6 +30,7 @@ int quiet;		/* Level of quietness */
 int reservenum;		/* Number of memory reservation slots */
 int minsize;		/* Minimum blob size */
 int padsize;		/* Additional padding to blob */
+int align_size;		/* Additional padding to blob accroding to the align size */
 int phandle_format = PHANDLE_BOTH;	/* Use linux,phandle or phandle properties */
 
 static void fill_fullpaths(struct node *tree, const char *prefix)
@@ -53,7 +54,7 @@ static void fill_fullpaths(struct node *tree, const char *prefix)
 #define FDT_VERSION(version)	_FDT_VERSION(version)
 #define _FDT_VERSION(version)	#version
 static const char usage_synopsis[] = "dtc [options] <input file>";
-static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:fb:i:H:sW:E:hv";
+static const char usage_short_opts[] = "qI:O:o:V:d:R:S:p:a:fb:i:H:sW:E:hv";
 static struct option const usage_long_opts[] = {
 	{"quiet",            no_argument, NULL, 'q'},
 	{"in-format",         a_argument, NULL, 'I'},
@@ -64,6 +65,7 @@ static struct option const usage_long_opts[] = {
 	{"reserve",           a_argument, NULL, 'R'},
 	{"space",             a_argument, NULL, 'S'},
 	{"pad",               a_argument, NULL, 'p'},
+	{"align",             a_argument, NULL, 'a'},
 	{"boot-cpu",          a_argument, NULL, 'b'},
 	{"force",            no_argument, NULL, 'f'},
 	{"include",           a_argument, NULL, 'i'},
@@ -91,6 +93,7 @@ static const char * const usage_opts_help[] = {
 	"\n\tMake space for <number> reserve map entries (for dtb and asm output)",
 	"\n\tMake the blob at least <bytes> long (extra space)",
 	"\n\tAdd padding to the blob of <bytes> long (extra space)",
+	"\n\tMake the blob align to the <bytes> (extra space)",
 	"\n\tSet the physical boot cpu",
 	"\n\tTry to produce output even if the input tree has errors",
 	"\n\tAdd a path to search for include files",
@@ -169,6 +172,7 @@ int main(int argc, char *argv[])
 	reservenum = 0;
 	minsize    = 0;
 	padsize    = 0;
+	align_size = 0;
 
 	while ((opt = util_getopt_long()) != EOF) {
 		switch (opt) {
@@ -196,6 +200,9 @@ int main(int argc, char *argv[])
 		case 'p':
 			padsize = strtol(optarg, NULL, 0);
 			break;
+		case 'a':
+			align_size = strtol(optarg, NULL, 0);
+			break;
 		case 'f':
 			force = true;
 			break;
diff --git a/dtc.h b/dtc.h
index 56212c8..b406d21 100644
--- a/dtc.h
+++ b/dtc.h
@@ -53,6 +53,7 @@ extern int quiet;		/* Level of quietness */
 extern int reservenum;		/* Number of memory reservation slots */
 extern int minsize;		/* Minimum blob size */
 extern int padsize;		/* Additional padding to blob */
+extern int align_size;		/* Additional padding to blob accroding to the align size */
 extern int phandle_format;	/* Use linux,phandle or phandle properties */
 
 #define PHANDLE_LEGACY	0x1
diff --git a/flattree.c b/flattree.c
index ec14954..733e32e 100644
--- a/flattree.c
+++ b/flattree.c
@@ -413,6 +413,13 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
 		fdt.totalsize = cpu_to_fdt32(tsize);
 	}
 
+	if (align_size > 0) {
+		int tsize = fdt32_to_cpu(fdt.totalsize);
+		padlen += (align_size - tsize % align_size);
+		tsize += padlen;
+		fdt.totalsize = cpu_to_fdt32(tsize);
+	}
+
 	/*
 	 * Assemble the blob: start with the header, add with alignment
 	 * the reserve buffer, add the reserve map terminating zeroes,
@@ -572,6 +579,9 @@ void dt_to_asm(FILE *f, struct boot_info *bi, int version)
 	if (padsize > 0) {
 		fprintf(f, "\t.space\t%d, 0\n", padsize);
 	}
+	if (align_size > 0) {
+		fprintf(f, "\t.space\t%d, 0\n", align_size);
+	}
 	emit_label(f, symprefix, "blob_abs_end");
 
 	data_free(strbuf);
-- 
1.9.1