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

Wolfgang Denk
2011-08-24T13:25:53Z

Dear Lukasz Majewski,

In message <20110824120744.097ba2c5@lmajewski.digital.local> you wrote:
>
> After reading dcache related threads I'd like to sum them up:
>
> 1. alloca() -> not acceptable to u-boot mainline by Wolfgang. I agree
> that alloca is NOT the way to go.
>
> 2. malloc/memalign -> avoidable to use
>
> 3. Mike's DMA_DECLARE_BUFFER(<buffer type>, <variable name>,
> <size in bytes>)
> solution looks OK for me, at least for the stack allocated data (e.g.
> ext_csd).
> However this proposed implementation has been NAK'ed by Wolfgang.
>
> I'm curious how this macro should look like? Is it only matter of code
> reordering or other approach shall be found?

I think I'd like to see a macro that can be used like this:

void *dma_buffer_pointer = DMA_BUFFER(size_in_bytes);

> 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.

Best regards,

Wolfgang Denk

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