[U-Boot] [PATCH 2/2] libfdt: return correct value if #size-cells property is not present

[Matthias Brugger]

Hi all,

On 26/07/2019 11:13, matthias.bgg at kernel.org wrote:
> From: Matthias Brugger <mbrugger at suse.com>
> 
> According to the device tree specification, the default value for
> was not present.
> 
> This patch also makes fdt_address_cells() and fdt_size_cells() conform
> to the behaviour documented in libfdt.h. The defaults are only returned
> if fdt_getprop() returns -FDT_ERR_NOTFOUND, otherwise the actual error
> is returned.
> 
> This is based on upstream commit:
> aa7254d ("libfdt: return correct value if #size-cells property is not present")
> but misses the test case part, as we don't implement them in u-boot.
> 
> Signed-off-by: Matthias Brugger <mbrugger at suse.com>

After running these two patches through the CI [1] I realized that three test
are failing:
test/py sandbox
test/py sandbox with clang
test/py sandbox_flattree

All three fail dm_test_fdt_translation() in the case "No translation for busses
with #size-cells == 0" [2].

Can anybody with more insight in the test infrastructure and the sandbox
architecture help me to identify if this is
a) a bug in the sandbox
b) a bug in our test
c) a bug in my patch

I write this because I'm pretty sure that it is not option c), as we just stick
to the specs here.

Regards,
Matthias

[1] https://travis-ci.org/mbgg/u-boot/builds/565955218
[2] https://github.com/u-boot/u-boot/blob/master/test/dm/test-fdt.c#L511

> ---
>  scripts/dtc/libfdt/fdt_addresses.c | 16 +++++++++++++---
>  scripts/dtc/libfdt/libfdt.h        |  2 +-
>  2 files changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/scripts/dtc/libfdt/fdt_addresses.c b/scripts/dtc/libfdt/fdt_addresses.c
> index 49537b578d..f13a87dfa0 100644
> --- a/scripts/dtc/libfdt/fdt_addresses.c
> +++ b/scripts/dtc/libfdt/fdt_addresses.c
> @@ -64,7 +64,7 @@ static int fdt_cells(const void *fdt, int nodeoffset, const char *name)
>  
>  	c = fdt_getprop(fdt, nodeoffset, name, &len);
>  	if (!c)
> -		return 2;
> +		return len;
>  
>  	if (len != sizeof(*c))
>  		return -FDT_ERR_BADNCELLS;
> @@ -78,10 +78,20 @@ static int fdt_cells(const void *fdt, int nodeoffset, const char *name)
>  
>  int fdt_address_cells(const void *fdt, int nodeoffset)
>  {
> -	return fdt_cells(fdt, nodeoffset, "#address-cells");
> +	int val;
> +
> +	val = fdt_cells(fdt, nodeoffset, "#address-cells");
> +	if (val == -FDT_ERR_NOTFOUND)
> +		return 2;
> +	return val;
>  }
>  
>  int fdt_size_cells(const void *fdt, int nodeoffset)
>  {
> -	return fdt_cells(fdt, nodeoffset, "#size-cells");
> +	int val;
> +
> +	val = fdt_cells(fdt, nodeoffset, "#size-cells");
> +	if (val == -FDT_ERR_NOTFOUND)
> +		return 1;
> +	return val;
>  }
> diff --git a/scripts/dtc/libfdt/libfdt.h b/scripts/dtc/libfdt/libfdt.h
> index 66f01fec53..5c778b115b 100644
> --- a/scripts/dtc/libfdt/libfdt.h
> +++ b/scripts/dtc/libfdt/libfdt.h
> @@ -1109,7 +1109,7 @@ int fdt_address_cells(const void *fdt, int nodeoffset);
>   *
>   * returns:
>   *	0 <= n < FDT_MAX_NCELLS, on success
> - *      2, if the node has no #size-cells property
> + *      1, if the node has no #size-cells property
>   *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
>   *		#size-cells property
>   *	-FDT_ERR_BADMAGIC,
>