From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCH] [V3] uartlite: move from byte accesses to word accesses Date: Wed, 17 Mar 2010 15:26:31 -0600 Message-ID: References: <873097b0-5388-45b1-8483-3ef01bf8351f@SG2EHSMHS005.ehs.local> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mail-yw0-f201.google.com ([209.85.211.201]:44516 "EHLO mail-yw0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755743Ab0CQV0w convert rfc822-to-8bit (ORCPT ); Wed, 17 Mar 2010 17:26:52 -0400 Received: by ywh39 with SMTP id 39so618406ywh.21 for ; Wed, 17 Mar 2010 14:26:51 -0700 (PDT) In-Reply-To: <873097b0-5388-45b1-8483-3ef01bf8351f@SG2EHSMHS005.ehs.local> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: John Linn Cc: John Linn , linux-serial@vger.kernel.org, jacmet@sunsite.dk, michal.simek@petalogix.com, john.williams@petalogix.com On Wed, Mar 17, 2010 at 12:04 PM, John Linn wrot= e: > > >> -----Original Message----- >> From: John Linn >> Sent: Wednesday, March 17, 2010 10:27 AM >> To: 'Grant Likely' >> Cc: linux-serial@vger.kernel.org; jacmet@sunsite.dk; michal.simek@pe= talogix.com; >> john.williams@petalogix.com >> Subject: RE: [PATCH] [V3] uartlite: move from byte accesses to word = accesses >> >> > -----Original Message----- >> > From: glikely@secretlab.ca [mailto:glikely@secretlab.ca] On Behalf= Of Grant Likely >> > Sent: Wednesday, March 17, 2010 10:21 AM >> > To: John Linn >> > Cc: linux-serial@vger.kernel.org; jacmet@sunsite.dk; michal.simek@= petalogix.com; >> > john.williams@petalogix.com >> > Subject: Re: [PATCH] [V3] uartlite: move from byte accesses to wor= d accesses >> > >> > On Wed, Mar 17, 2010 at 9:40 AM, John Linn = wrote: >> > > Byte accesses for I/O devices in Xilinx IP is going to be less >> > > desired in the future such that the driver is being changed to >> > > use 32 bit accesses. >> > > >> > > This change facilitates using the uartlite IP over a PCIe bus >> > > which only allows 32 bit accesses. >> > > >> > > Signed-off-by: John Linn >> > > >> > > --- >> > > >> > > V2 - updated the commit message based on Peter's comments >> > > >> > > V3 - removed u8 casting based on Peter's comments, cleaned up an= d >> > > simplified the change by using raw I/O functions rather than >> > > using in_be32 & out_be32 functions. >> > >> > The __raw_{read,write}l() functions aren't the best choice here. =A0= User >> > ioread32be(), iowrite32be() instead if you want them to work >> > cross-architecture (see include/asm-generic/iomap.h). >> >> Maybe the ioread functions will work better than the in/out_be32 as = they >> were not working like I wanted. >> >> I'm still trying to get my head wrapped around the right I/O functio= ns to use since there are so many >> options. >> >> I'll look at your suggestions. > > That works ok on Powerpc, but not microblaze yet as there are still p= atches in the process of going into the kernel for that. > > Do we need to wait til those patches are in? I'd make it broken in Kconfig on microblaze until those patches get merged. To the best of my knowledge, the ioread/write routines are the best functions to use for cross-architecture MMIO code. g. -- To unsubscribe from this list: send the line "unsubscribe linux-serial"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html