From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 26 May 2009 02:25:08 -0700 (PDT) Message-Id: <20090526.022508.238274281.davem@davemloft.net> To: arnd@arndb.de Subject: Re: [net-next-2.6 PATCH v2] can: SJA1000: generic OF platform bus driver From: David Miller In-Reply-To: <200905261010.31364.arnd@arndb.de> References: <200905242327.15139.arnd@arndb.de> <4A1A418D.3040207@grandegger.com> <200905261010.31364.arnd@arndb.de> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Cc: linuxppc-dev@ozlabs.org, devicetree-discuss@ozlabs.org, netdev@vger.kernel.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Arnd Bergmann Date: Tue, 26 May 2009 10:10:30 +0100 > On Monday 25 May 2009, Wolfgang Grandegger wrote: >> > Right, that makes sense. However, most drivers use the field to store the >> > physical address, not the iomap token. Maybe there should be a new field >> > in struct sja1000_priv for the virtual address, but that would be a change >> > to the base driver, not just to the OF portion. >> >> Is that common practice? If yes, I will add a member to store the >> virtual address to struct sja1000_priv. > > I grepped through the network driver for usage of ->base_addr, and > it's somewhat inconsistent. The majority of the users use it for > a physical address, but there are also a few that use it for the > __iomem token. > > Casts between unsigned long and qualified (__iomem, __user, const, ...) > pointers do not cause a warning, but can easily lead to bugs when > another user casts to an unqualified pointer. It's such a baroque thing, there is no reason to set it at all if you ask me. It's only use is to allow ISA and similar primitive bus devices to have their I/O ports changed via ifconfig.