From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Leonid Grossman" Subject: RE: FW: Submission for S2io 10GbE driver Date: Wed, 4 Feb 2004 12:44:21 -0800 Sender: netdev-bounce@oss.sgi.com Message-ID: <004201c3eb5f$ac4e9f00$740efea9@S2IOtech.com> References: <20040123232209.2739e6aa.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: , "'Ragu Vatsavayi'" , "'Grant Grundler'" Return-path: To: "'Andi Kleen'" In-Reply-To: <20040123232209.2739e6aa.ak@suse.de> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org > All the ARCH_PPC64 ifdefs shouldn't be needed. Can you remove > that? If there are problems in ppc64 code they should be > fixed there, not worked around. Same with the ifdefs for > kernel 2.6 features. An driver integrated into the kernel > should not contain such ifdefs. Hi Andi, You are right some of the ifdefs are not needed and we are removing these; it is not clear if we can get rid of all of them for the following reasons: 1) We did't find quad word memory operations(writeq and readq) on PCI bus for PPC64 architecture. 2) We did't had a chance to test the driver on other big endian systems apart from PPC64. In PPC64 architecture though, I write/read a value to/from ioremaped address it swaps the value and behaves like a little endian m/c: For ex: if I do writel(0x12345678, addr) then in it writes addr: 78, (addr+1):56, (addr+2):34, (addr+3):12 On a little endian m/c like IA32 also writel writes same values in a similar manner as shown above. So the question is - Do all big endian machines with linux OS swap the values and write in little endian format?? 3)In PPC64 architecture dma_addr_t is u32, unlike remaining 64 bit architectures where it is defined as u64. Because of this we have to deal separately for PP64. So any suggestions will be useful, .i.e. generally how PPC64 developers deal with this? Say if we have some structure corresponding to memory region of our hardware device which should be of 16 bytes. struct hw { dma_addr_t phys; char *virt; #ifdef ARCH32 u64 dummy; #endif } Then above definition will not work for PPC64, we need to modify it like this: struct hw { dma_addr_t phys; char *virt; #ifdef ARCH32 u64 dummy; #endif #ifdef ARCH_PPC64 u32 dummy; #endif }