From mboxrd@z Thu Jan  1 00:00:00 1970
From: Marek Vasut <marex@denx.de>
Date: Sat, 10 Oct 2015 20:10:01 +0200
Subject: [U-Boot] [PATCH] nios2: zap cache status enable and disable
	functions
In-Reply-To: <5618C086.4000706@wytron.com.tw>
References: <1444361567-27328-1-git-send-email-thomas@wytron.com.tw>
 <201510091457.00490.marex@denx.de> <5618C086.4000706@wytron.com.tw>
Message-ID: <201510102010.01110.marex@denx.de>
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To: u-boot@lists.denx.de

On Saturday, October 10, 2015 at 09:38:46 AM, Thomas Chou wrote:
> 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.

OK, now it's clearer to me what you mean, thanks.

Best regards,
Marek Vasut