From: Thomas Chou <thomas@wytron.com.tw>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH] nios2: zap cache status enable and disable functions
Date: Sat, 10 Oct 2015 15:38:46 +0800 [thread overview]
Message-ID: <5618C086.4000706@wytron.com.tw> (raw)
In-Reply-To: <201510091457.00490.marex@denx.de>
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
next prev parent reply other threads:[~2015-10-10 7:38 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-09 3:32 [U-Boot] [PATCH] nios2: zap cache status enable and disable functions Thomas Chou
2015-10-09 12:57 ` Marek Vasut
2015-10-10 7:38 ` Thomas Chou [this message]
2015-10-10 18:10 ` Marek Vasut
2015-10-13 13:19 ` Thomas Chou
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