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/
WARNING: multiple messages have this Message-ID (diff)
From: David Vrabel <dvrabel@arcom.com>
To: Jonathan McDowell <noodles@earth.li>
Cc: "Jörn Engel" <joern@wohnheim.fh-wedel.de>,
linux-mtd@lists.infradead.org, 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/
next prev parent reply other threads:[~2006-05-19 9:32 UTC|newest]
Thread overview: 13+ 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 9:32 ` David Vrabel
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 0:10 ` Segher Boessenkool
2006-05-19 22:20 ` Jonathan McDowell
2006-05-20 14:10 ` Jonathan McDowell
2006-05-21 17:12 ` David Woodhouse
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