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From: Albert ARIBAUD <albert.u.boot@aribaud.net>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 1/2] mmc: add bcm2835 driver
Date: Sun, 4 Nov 2012 16:32:32 +0100	[thread overview]
Message-ID: <20121104163232.2bb93c5d@lilith> (raw)
In-Reply-To: <508D6611.1040409@gmail.com>

Hi Stephen,

On Sun, 28 Oct 2012 22:36:25 +0530, Vikram Narayanan
<vikram186@gmail.com> wrote:

> On 10/28/2012 8:58 AM, Stephen Warren wrote:
> > On 10/26/2012 05:33 AM, Vikram Narayanan wrote:
> >> Some nitpicks.
> >>
> >> On 10/24/2012 10:20 AM, Stephen Warren wrote:
> <snip>
> >>> +static u8 bcm2835_sdhci_readb(struct sdhci_host *host, int reg)
> >>> +{
> >>> +    u32 val = bcm2835_sdhci_raw_readl(host, (reg&   ~3));
> >>> +    val = val>>   (reg<<   3&   0x18)&   0xff;
> >>> +
> >>> +    return (u8)val;
> >>> +}
> >>
> >> Can the above used magics be made as macros?
> >
> > This code was taken directly from the downstream Linux kernel, so I
> > changed it as little as possible, to make comparisons easier. Still, if
> > people want I can certainly make it easier to understand the expression
> > a bit.
> 
> Seems reasonable.
> 
> > I don't think the issue is the magic numbers so much as understanding
> > what the expression does; the magic are obvious then. It's simply
> > extracting byte n from from a u32. Would the following be more obvious:
> >
> > byte_num = reg&  3;
> > byte_shift = bytenum * 8;
> > byte = (val>>  byte_shift)&  0xff;
> >
> > ... and similar for the other functions?
> 
> This looks better to me than the former. Thanks.

Stephen,

Does this mean there'll be a new version of this patch?

Amicalement,
-- 
Albert.

  reply	other threads:[~2012-11-04 15:32 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-10-24  4:50 [U-Boot] [PATCH 1/2] mmc: add bcm2835 driver Stephen Warren
2012-10-24  4:50 ` [U-Boot] [PATCH 2/2] ARM: rpi_b: enable SD controller, add related env/cmds Stephen Warren
2012-10-26 11:33 ` [U-Boot] [PATCH 1/2] mmc: add bcm2835 driver Vikram Narayanan
2012-10-28  3:28   ` Stephen Warren
2012-10-28 17:06     ` Vikram Narayanan
2012-11-04 15:32       ` Albert ARIBAUD [this message]
2012-11-04 17:15         ` Stephen Warren
2012-10-26 17:32 ` Tom Rini
2012-10-26 17:48   ` Oleksandr Tymoshenko
2012-10-26 18:05     ` Tom Rini
2012-10-26 18:21       ` Stephen Warren
2012-10-26 18:10     ` Greg KH

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