Re: [PATCH] dtc: Add command line option to force size alignment of blob.

[Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org>]

On Fri, Nov 12, 2010 at 10:02:00AM -0800, dirk.brandewie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org wrote:
> From: Dirk Brandewie <dirk.brandewie-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
> 
> This patch adds a command line argument to allow the user to request
> the that the blob be padded out to modulo <bytes> size.
> 
> Signed-off-by: Dirk Brandewie <dirk.j.brandewie-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>

As commented elsewhere; this option isn't needed.  The kernel should
handle its own alignment requirements.  Nack.

g.

> ---
>  Documentation/manual.txt |    3 +++
>  dtc.c                    |   10 ++++++++--
>  flattree.c               |   20 +++++++++++++++++++-
>  3 files changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/manual.txt b/Documentation/manual.txt
> index f8a8a7b..c899396 100644
> --- a/Documentation/manual.txt
> +++ b/Documentation/manual.txt
> @@ -117,6 +117,9 @@ Options:
>  	Ensure the blob at least <bytes> long, adding additional
>  	space if needed.
>  
> +    -a <bytes>
> +        Ensure the blob is modulo <bytes> in length.
> + 
>      -v
>  	Print DTC version and exit.
>  
> diff --git a/dtc.c b/dtc.c
> index 8b31d20..4e1abd4 100644
> --- a/dtc.c
> +++ b/dtc.c
> @@ -77,6 +77,8 @@ static void  __attribute__ ((noreturn)) usage(void)
>  	fprintf(stderr, "\t\tMake the blob at least <bytes> long (extra space)\n");
>  	fprintf(stderr, "\t-p <bytes>\n");
>  	fprintf(stderr, "\t\tAdd padding to the blob of <bytes> long (extra space)\n");
> +	fprintf(stderr, "\t-a <bytes>\n");
> +	fprintf(stderr, "\t\t Add padding make the blob modulo <bytes> in size\n");
>  	fprintf(stderr, "\t-b <number>\n");
>  	fprintf(stderr, "\t\tSet the physical boot cpu\n");
>  	fprintf(stderr, "\t-f\n");
> @@ -108,8 +110,9 @@ int main(int argc, char *argv[])
>  	reservenum = 0;
>  	minsize    = 0;
>  	padsize    = 0;
> -
> -	while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:fcqb:vH:")) != EOF) {
> +	align_size = 0;
> +	
> +	while ((opt = getopt(argc, argv, "hI:O:o:V:R:S:p:a:fcqb:vH:")) != EOF) {
>  		switch (opt) {
>  		case 'I':
>  			inform = optarg;
> @@ -132,6 +135,9 @@ int main(int argc, char *argv[])
>  		case 'p':
>  			padsize = strtol(optarg, NULL, 0);
>  			break;
> +		case 'a':
> +			alignsize = strtol(optarg, NULL, 0);
> +			break;
>  		case 'f':
>  			force = 1;
>  			break;
> diff --git a/flattree.c b/flattree.c
> index ead0332..e908609 100644
> --- a/flattree.c
> +++ b/flattree.c
> @@ -373,7 +373,8 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
>  	struct data strbuf     = empty_data;
>  	struct fdt_header fdt;
>  	int padlen = 0;
> -
> +	int align_len = 0;
> +	
>  	for (i = 0; i < ARRAY_SIZE(version_table); i++) {
>  		if (version_table[i].version == version)
>  			vi = &version_table[i];
> @@ -411,6 +412,20 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
>  	}
>  
>  	/*
> +	 * If the user asked for alignment of the end of the blob,
> +	 * adjust the totalsize. 
> +	 */
> +
> +	if (align_size > 0)
> +		align_len = align_size;
> +
> +	if (align_len > 0) {
> +		int tsize = fdt32_to_cpu(fdt.totalsize);
> +		tsize += alignlen;
> +		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,
>  	 * the device tree itself, and finally the strings.
> @@ -427,6 +442,9 @@ void dt_to_blob(FILE *f, struct boot_info *bi, int version)
>  	 */
>  	if (padlen > 0)
>  		blob = data_append_zeroes(blob, padlen);
> +	
> +	if (align_len > 0)
> +		blob = data_append_align(blob, align_len);
>  
>  	if (fwrite(blob.val, blob.len, 1, f) != 1) {
>  		if (ferror(f))
> -- 
> 1.7.2.3
> 
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