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@xxxxxxxxxxxx>
> ---
> 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
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