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 11:48:52 +0100 Message-ID: <4B20D214.4050503@grandegger.com> References: <1260430072-21106-1-git-send-email-21cnbao@gmail.com> <4B20BB36.50509@grandegger.com> <8bd0f97a0912100204gd2b09f6r2799d9f951d6b9e1@mail.gmail.com> <4B20CB82.6060702@grandegger.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "H.J. Oertel" , netdev@vger.kernel.org, socketcan-core@lists.berlios.de, uclinux-dist-devel@blackfin.uclinux.org, davem@davemloft.net To: Mike Frysinger Return-path: Received: from mail-out.m-online.net ([212.18.0.9]:45547 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933615AbZLJKtb (ORCPT ); Thu, 10 Dec 2009 05:49:31 -0500 In-Reply-To: <4B20CB82.6060702@grandegger.com> Sender: netdev-owner@vger.kernel.org List-ID: 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. > >>> 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 I was just wondering if bfin_read/write16 would not be the proper accessor functions. readw/writew seems to be implemented differently: http://lxr.linux.no/#linux+v2.6.32/arch/blackfin/include/asm/io.h#L44 Puh, they do an cli,nop,nop,sync..sti for the access. This also nicely shows why accessor functions should be used to access device registers. Well, just curious. I don't really know the blackfin arch. Wolfgang.