From mboxrd@z Thu Jan  1 00:00:00 1970
From: Aneesh V <aneesh@ti.com>
Date: Tue, 19 Jul 2011 17:21:32 +0530
Subject: [U-Boot] i.MX51: FEC: Cache coherency problem?
In-Reply-To: <4E256588.4010301@arcor.de>
References: <20110718171836.67bfe605@archvile> <4E245C5C.4030303@ti.com>
	<4E256588.4010301@arcor.de>
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Dear Matthias,

On Tuesday 19 July 2011 04:37 PM, Matthias Wei?er wrote:
> Dear Aneesh
>
> Am 18.07.2011 18:16, schrieb Aneesh V:
>> commit c2dd0d45540397704de9b13287417d21049d34c6
>> armv7: integrate cache maintenance support
>>
>> In this patch I added a call to dcache_enable() at the beginning of
>> board_init_r() for ARM(i.e. as soon as relocation is over). As a result
>> D-cache will be enabled for all ARM platforms now unless
>> CONFIG_SYS_DCACHE_OFF is set.
>
> Is this really a good idea? This will break a couple of boards using
> non-cache-aware drivers. And there are a couple of them in u-boot. I
> think d-cache should be opt-in rather then opt-out as long as there are
> any drivers which didn't handle cached memory regions correct. i-cache
> is much less problematic and can be enabled by default.

D-cache was always an opt-out in u-boot based on the fact that the flag
was CONFIG_SYS_DCACHE_OFF and not something like
CONFIG_SYS_DCACHE_ENABLE. I just made the behavior more consistent and
predictable. Also, my idea was to enable it(if allowed by the config
flag) at the earliest possible time rather than waiting for a random
driver or board file to enable it much later.

Regarding the question of whether it should be opt-out or opt-in I have
no preference myself.

best regards,
Aneesh