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Message-ID: <5BAE2D6F9E6047C19B6BE8FF26F7270B@subhasishg>
Date: Wed, 27 Apr 2011 18:48:54 +0530
From: "Subhasish Ghosh" <subhasish@...tralsolutions.com>
To: "Russell King - ARM Linux" <linux@....linux.org.uk>,
"Marc Kleine-Budde" <mkl@...gutronix.de>
Cc: <sachi@...tralsolutions.com>,
<davinci-linux-open-source@...ux.davincidsp.com>,
"Samuel Ortiz" <sameo@...ux.intel.com>, <nsekhar@...com>,
"open list" <linux-kernel@...r.kernel.org>, <m-watkins@...com>,
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v4 01/11] mfd: add pruss mfd driver.
My problem is, I am doing something like this:
s32 pruss_writel_multi(struct device *dev, u32 offset,
u32 *pdatatowrite, u16 wordstowrite)
{
struct pruss_priv *pruss = dev_get_drvdata(dev->parent);
u32 __iomem *paddresstowrite;
u16 i;
paddresstowrite = pruss->ioaddr + offset;
for (i = 0; i < wordstowrite; i++)
iowrite32(*pdatatowrite++, paddresstowrite++);
return 0;
}
So, if I make paddresstowrite as void, it will not work.
The above implementation does not generate any sparse errors though.
> On Wed, Apr 27, 2011 at 09:29:59AM +0200, Marc Kleine-Budde wrote:
>> On 04/27/2011 08:39 AM, Subhasish Ghosh wrote:
>> > - Is it ok to have u32 etc for __iomem cookie ?
>>
>> no - "void __iomem *" is "void __iomem *"
>
> Actually, it is _provided_ you don't directly dereference it. You can
> then do pointer arithmetic on it in the usual way - which is about the
> only valid thing to do with an __iomem pointer. The voidness just acts
> as an additional check against direct dereferences of this.
>
> The important thing though is that the code passes sparse checks.
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