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

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