[U-Boot] [PATCH 3/4] MX51: Add video support

[stefano babic]

Wolfgang Denk wrote:
> Dear Stefano Babic,
> 
> In message <1286875504-9058-4-git-send-email-sbabic at denx.de> you wrote:
>> Add framebuffer driver for the MX51 processor
>> working on the IPUv3 internal graphic processor.
> 
> Please add reference to original sources.

Ok

> 
> 
>> +/*
>> + * Allocates the DRAM memory for the frame buffer.      This buffer is remapped
>> + * into a non-cached, non-buffered, memory region to allow palette and pixel
>> + * writes to occur without flushing the cache.  Once this area is remapped,
>> + * all virtual memory access to the video memory should occur at the new region.
> 
> Is this comment still valid for the U-Boot port?  

No, it is not. The comment makes no sense for u-boot. There is no
allocation and malloc is not called, as the memory for the framebuffer
is taken from the lcd_base variable.

> 
> Does it work with both "dcache on" and "dcache off" settings?

Well, as there is not yet support for L2-Cache on the MX51, we can say
yes ;-). However, this range of memory is used directly from the IPU
processor and not by the CPU, as well as in Linux without calling any
function to invalidate the cache. But I agree, it should be tested again
when support for L2-cache will be integrated.

Stefano


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