[U-Boot] [PATCH] mmc:dcache: Cache line size aligned internal MMC buffers

Anton Staaf
2011-08-24T18:25:42Z

On Wed, Aug 24, 2011 at 11:12 AM, Wolfgang Denk <wd@denx.de> wrote:
> Dear Anton Staaf,
>
> In message <CAF6FioWBsjFa+QdFNHEQGO50eLoqZMc--Yt3-iYX6DWr=hcOrg@mail.gmail.com> you wrote:
>>
>> >> 4. get_dcache_line_size() can be simply defined as
>> >> #define get_dcache_line_size() CONFIG_SYS_CACHE_LINE_SIZE if we
>> >> _really_ want to save a few bytes.
>> >
>> > Actually I fail to understand why we would ever need
>> > get_dcache_line_size() in a boot loader.
>>
>> It is required so that we can correctly allocate buffers that will be
>> used by DMA engines to read or write data. ?The reason that these
>
> No, it is definitely NOT needed for this purpose - we have been using
> CONFIG_SYS_CACHE_LINE_SIZE for more than a decade without problems, so
> I don't really understand why we now would need a new function for
> this?

Ahh, I misunderstood your question. I thought you were asking about
the need to know the cache line size. Not it's specific
implementation as a function call. In which case, I agree, and am
happy to use CONFIG_SYS_CACHE_LINE_SIZE, though I don't see any
definitions of CONFIG_SYS_CACHE_LINE_SIZE in the entire U-Boot tree.
What have I missed?

Thanks,
Anton

>
> Best regards,
>
> Wolfgang Denk
>
> --
> DENX Software Engineering GmbH, ? ? MD: Wolfgang Denk & Detlev Zundel
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
> Brain: an apparatus with which we think we think. ? ?- Ambrose Bierce
>