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From: David Vrabel <dvrabel@arcom.com>
To: Jonathan McDowell <noodles@earth.li>
Cc: linux-mtd@lists.infradead.org,
	"Jörn Engel" <joern@wohnheim.fh-wedel.de>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] Add Amstrad Delta NAND support.
Date: Fri, 19 May 2006 10:32:37 +0100	[thread overview]
Message-ID: <446D90B5.2090802@arcom.com> (raw)
In-Reply-To: <20060519090142.GB7570@earth.li>

Jonathan McDowell wrote:
> On Thu, May 18, 2006 at 06:57:28PM +0200, Jörn Engel wrote:
>> On Thu, 18 May 2006 17:09:41 +0100, Jonathan McDowell wrote:
>>> +	omap_writew(0, (OMAP_MPUIO_BASE + OMAP_MPUIO_IO_CNTL));
>>                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>> Could that be done in a macro?
> 
> Is there any benefit to doing so?
> 
>>> +	udelay(0.04);
>> Floating point in the kernel?
> 
> Not quite. udelay is a macro on ARM so this ends up as an integer before
> it ever hits a function call. In an ideal world I'd use "ndelay(40);"
> but that would result in a delay of over 1µs as ARM doesn't have ndelay
> defined so we hit the generic fallback.

Use instead:

/* delay for at least 40 ns */
udelay(1);

Or better yet provide an ndelay implementation for ARM.

David Vrabel
-- 
David Vrabel, Design Engineer

Arcom, Clifton Road           Tel: +44 (0)1223 411200 ext. 3233
Cambridge CB1 7EA, UK         Web: http://www.arcom.com/

  reply	other threads:[~2006-05-19  9:32 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-05-18 16:09 [PATCH] Add Amstrad Delta NAND support Jonathan McDowell
2006-05-18 16:57 ` Jörn Engel
2006-05-19  9:01   ` Jonathan McDowell
2006-05-19  9:32     ` David Vrabel [this message]
2006-05-19 10:01       ` Jonathan McDowell
2006-05-19 10:03     ` Jörn Engel
2006-05-19 10:26       ` David Woodhouse
2006-05-20  0:10         ` Segher Boessenkool
2006-05-20 14:10 ` Jonathan McDowell
2006-05-21 17:12   ` David Woodhouse

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