From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfgang Grandegger Subject: Re: [Uclinux-dist-devel] [PATCH v3] add the driver for Analog Devices Blackfin on-chip CAN controllers Date: Thu, 10 Dec 2009 11:55:24 +0100 Message-ID: <4B20D39C.6030103@grandegger.com> References: <1260430072-21106-1-git-send-email-21cnbao@gmail.com> <4B20BB36.50509@grandegger.com> <8bd0f97a0912100204gd2b09f6r2799d9f951d6b9e1@mail.gmail.com> <4B20CB82.6060702@grandegger.com> <8bd0f97a0912100245k9930c90ke4b184da68a9f958@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "H.J. Oertel" , netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, socketcan-core-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org, uclinux-dist-devel-ZG0+EudsQA8dtHy/vicBwGD2FQJk+8+b@public.gmane.org, davem-fT/PcQaiUtIeIZ0/mPfg9Q@public.gmane.org To: Mike Frysinger Return-path: In-Reply-To: <8bd0f97a0912100245k9930c90ke4b184da68a9f958-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org Errors-To: socketcan-core-bounces-0fE9KPoRgkgATYTw5x5z8w@public.gmane.org List-Id: netdev.vger.kernel.org Mike Frysinger wrote: > On Thu, Dec 10, 2009 at 05:20, Wolfgang Grandegger wrote: >> Mike Frysinger wrote: >>> On Thu, Dec 10, 2009 at 04:11, Wolfgang Grandegger wrote: >>>> Barry Song wrote: >>>>> +#include >>>>> +#include >>>>> +#include >>>>> +#include >>>> I think you don't need "types.h" as the code no longer uses "uint*_t". >>> linux/types.h declares all types, like u* which this driver still uses >> I just remember that "linux/types.h" needs to be added for the uint*_t >> types. At a first glance I do not see __u8/u8 being defined in that >> header file but I might have missed something. > > you need to follow the include paths I thought I did. Could you point me to the relevant location? >>>> Well, I'm still not a friend of the following inline functions, >>>> especially the *one-liners* which are called just *once*. With the usage >>>> of structs they seem even more useless. >>> seems like it would make more sense to not even use the read/write >>> functions either. just declare the regs as volatile and assign/read >>> the struct directly. >> Two times no. Don't use volatile and proper accessor functions. See: >> >> http://lxr.linux.no/#linux+v2.6.32/Documentation/volatile-considered-harmful.txt > > too bad the document is largely irrelevant (all but one paragraph) > because this is how volatiles were designed in the first place -- > hardware I/O registers. the CAN implementation here is Blackfin > specific and not going to be use elsewhere, so other architectures are > irrelevant. the resulting C code would certainly look a hell of a lot > more natural without the useless I/O accessor functions, and be much > tighter. Well, so far *no* volatiles have been used in the BFIN CAN driver. But if you tell me that they are really required for blackfin... I can't really judge. > at any rate, the common Blackfin I/O accessor functions force a lot of > useless overhead when used here as they're designed for async memory, > not MMRs. the driver needs to be switched to the bfin_read/bfin_write > MMR functions. I just brought up this issue in another mail. Wolfgang. > >