[U-Boot] [RFC PATCH 08/10] SPL: read and store arch property from U-Boot image

[Simon Glass]

Hi Andre,

On 17 November 2016 at 18:50, André Przywara <andre.przywara at arm.com> wrote:
> On 05/11/16 16:10, Simon Glass wrote:
>
> Hi Simon,
>
>> On 2 November 2016 at 19:36, Andre Przywara <andre.przywara at arm.com> wrote:
>>> Read the specified "arch" value from a legacy or FIT U-Boot image and
>>> store it in our SPL data structure.
>>> This allows loaders to take the target architecture in account for
>>> custom loading procedures.
>>> Having the complete string -> arch mapping for FIT based images in the
>>> SPL would be too big, so we leave it up to architectures (or boards) to
>>> overwrite the weak function that does the actual translation, possibly
>>> covering only the required subset there.
>>>
>>> Signed-off-by: Andre Przywara <andre.przywara at arm.com>
>>> ---
>>>  common/spl/spl.c     | 1 +
>>>  common/spl/spl_fit.c | 8 ++++++++
>>>  include/spl.h        | 3 ++-
>>>  3 files changed, 11 insertions(+), 1 deletion(-)
>>>
>>
>> Reviewed-by: Simon Glass <sjg at chromium.org>
>
> Thanks!
>
>>
>>> diff --git a/common/spl/spl.c b/common/spl/spl.c
>>> index bdb165a..f76ddd2 100644
>>> --- a/common/spl/spl.c
>>> +++ b/common/spl/spl.c
>>> @@ -114,6 +114,7 @@ int spl_parse_image_header(struct spl_image_info *spl_image,
>>>                                 header_size;
>>>                 }
>>>                 spl_image->os = image_get_os(header);
>>> +               spl_image->arch = image_get_arch(header);
>>>                 spl_image->name = image_get_name(header);
>>>                 debug("spl: payload image: %.*s load addr: 0x%x size: %d\n",
>>>                         (int)sizeof(spl_image->name), spl_image->name,
>>> diff --git a/common/spl/spl_fit.c b/common/spl/spl_fit.c
>>> index aae556f..a5d903b 100644
>>> --- a/common/spl/spl_fit.c
>>> +++ b/common/spl/spl_fit.c
>>> @@ -123,6 +123,11 @@ static int get_aligned_image_size(struct spl_load_info *info, int data_size,
>>>         return (data_size + info->bl_len - 1) / info->bl_len;
>>>  }
>>>
>>> +__weak u8 spl_genimg_get_arch_id(const char *arch_str)
>>> +{
>>> +       return IH_ARCH_DEFAULT;
>>> +}
>>> +
>>
>> Do we need this weak function, or could we just add a normal function
>> in the ARM code somewhere?
>
> Mmh, but this here is generic code. In a later patch I provide an ARM
> specific function under arch/arm, but so far this weak function just
> mimics the current behaviour: return the current architecture.
>
>> If you don't think we need much error checking you could do something like:
>>
>> #ifdef CONFIG_ARM
>> ... possible strcmp() here
>> return IH_ARCH_ARM;
>> #endif
>
> So I found the weak function more elegant than #ifdef-ing architecture
> specific code into a generic file.

Fair enough.

> Is there any issue with weak functions, shall we avoid them?

Well they can be confusing since it's hard to know which function gets
linked in. We have things like CONFIG_MISC_INIT_F, rather than make
misc_init() weak.

>
>>
>>>  int spl_load_simple_fit(struct spl_image_info *spl_image,
>>>                         struct spl_load_info *info, ulong sector, void *fit)
>>>  {
>>> @@ -136,6 +141,7 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
>>>         int base_offset, align_len = ARCH_DMA_MINALIGN - 1;
>>>         int src_sector;
>>>         void *dst, *src;
>>> +       const char *arch_str;
>>>
>>>         /*
>>>          * Figure out where the external images start. This is the base for the
>>> @@ -184,10 +190,12 @@ int spl_load_simple_fit(struct spl_image_info *spl_image,
>>>         data_offset = fdt_getprop_u32(fit, node, "data-offset");
>>>         data_size = fdt_getprop_u32(fit, node, "data-size");
>>>         load = fdt_getprop_u32(fit, node, "load");
>>> +       arch_str = fdt_getprop(fit, node, "arch", NULL);
>>>         debug("data_offset=%x, data_size=%x\n", data_offset, data_size);
>>>         spl_image->load_addr = load;
>>>         spl_image->entry_point = load;
>>>         spl_image->os = IH_OS_U_BOOT;
>>> +       spl_image->arch = spl_genimg_get_arch_id(arch_str);
>>>
>>>         /*
>>>          * Work out where to place the image. We read it so that the first
>>> diff --git a/include/spl.h b/include/spl.h
>>> index e080a82..6a9d2fb 100644
>>> --- a/include/spl.h
>>> +++ b/include/spl.h
>>> @@ -22,11 +22,12 @@
>>>
>>>  struct spl_image_info {
>>>         const char *name;
>>> -       u8 os;
>>>         u32 load_addr;
>>>         u32 entry_point;
>>>         u32 size;
>>>         u32 flags;
>>> +       u8 os;
>>> +       u8 arch;
>>
>> Can you please add a struct comment?
>
> Is that something specific / a special documentation format or do you
> mean just document the structure members?

The latter - see struct spl_load_info for an example. If we improve
the code we change everyone wins :-)

Regards,
Simon

>