netdev - Re: [PATCH net-next-2.6 1/2] can: add driver for Softing card

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Message-ID: <4D2311B2.7000401@pengutronix.de>
Date:	Tue, 04 Jan 2011 13:25:22 +0100
From:	Marc Kleine-Budde <mkl@...gutronix.de>
To:	Kurt Van Dijck <kurt.van.dijck@....be>
CC:	socketcan-core@...ts.berlios.de, netdev@...r.kernel.org
Subject: Re: [PATCH net-next-2.6 1/2] can: add driver for Softing card

On 01/04/2011 01:19 PM, Kurt Van Dijck wrote:
> On Fri, Dec 24, 2010 at 12:44:08PM +0100, Marc Kleine-Budde wrote:
>>
>>>> hmmm..all stuff behind dpram is __iomem, isn't it? I think it should
>>>> only be accessed with via the ioread/iowrite operators. Please check
>>> I did an ioremap_nocache. Since it is unaligned, ioread/iowrite would render
>>> a lot of statements.
>>
>> The thing is, ioremapped mem should not be accessed directly. Instead
>> ioread/iowrite should be used. The softing driver should work on non x86
>> platforms, too.
>>
>>>> your code with sparse (compile with "make C=2").
>>> (?)
>>
>> Sparse, a static syntax analyser tool, see "Documentation/sparse.txt".
>> It throws the following warnings on your driver:
>>
>>> make drivers/net/can/softing/softing.ko C=2
>>>   CHK     include/linux/version.h
>>>   CHK     include/generated/utsrelease.h
>>>   CALL    scripts/checksyscalls.sh
>>>   CHECK   scripts/mod/empty.c
>>>   CHECK   drivers/net/can/softing/softing_main.c
>>> drivers/net/can/softing/softing_main.c:98:15: warning: incorrect type in argument 1 (different address spaces)
>>> drivers/net/can/softing/softing_main.c:98:15:    expected void volatile [noderef] <asn:2>*dst
>>> drivers/net/can/softing/softing_main.c:98:15:    got unsigned char [usertype] *[assigned] ptr
> [...]
>>
>> You should start with fixing the assignment of the ioremapped memory
>> (drivers/net/can/softing/softing_main.c:835), the fix the rest.
>>
> (Thanks for the explanation)^2.
> 
> I left my code now with the only warning from sparse:

Good!

> warning: Using plain integer as NULL pointer
> 
> That means, I got all __iomem references fixed.
> Is this '0' instead of 'NULL' a big problem? I got plenty of those.

No problem for the compiler, but it's bad style :)
Please fix it.

cheers, Marc
-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
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