[U-Boot] [PATCH] nios2: zap cache status enable and disable functions

[Thomas Chou]

Hi Marek,

On 10/09/2015 08:57 PM, Marek Vasut wrote:
> On Friday, October 09, 2015 at 05:32:47 AM, Thomas Chou wrote:
>> As the icache and dcache of nios2 are always enabled, the
>> cmd_cache is no of use and the cache status, enable and
>> disable functions can be removed.
>
> This is no good, I want to be able to enable/disable caches to look
> for DMA-related issues. That is, if I disable cache, the suspicious
> driver works and if I enable cache, the driver does not work, I can
> conclude that it's a DMA/cache-related issue.

I understand. But the hardware always enables the cache if it is 
configured in nios2 cpu.

We can bypass (partially disable) the cache using ioremap() or 
dma_alloc_coherent(). If the DMA buffer address is mangled with 
ioremap(), then it is uncached. You may use this to debug.

Best regards,
Thomas Chou