From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp6.netcologne.de (smtp6.netcologne.de [194.8.194.26]) by ozlabs.org (Postfix) with ESMTP id 7B1E7B6EED for ; Fri, 9 Jul 2010 04:47:29 +1000 (EST) Date: Thu, 08 Jul 2010 20:40:13 +0200 From: Albrecht =?iso-8859-1?b?RHJl3w==?= Subject: Re: [PATCH] arch/powerpc/lib/copy_32.S: Use alternate memcpy for MPC512x and MPC52xx To: Grant Likely In-Reply-To: (from grant.likely@secretlab.ca on Thu Jul 8 17:22:03 2010) Message-Id: <1278614421.1801.0@antares> MIME-Version: 1.0 Content-Type: multipart/signed; protocol="application/pgp-signature"; micalg=PGP-SHA1; boundary="=-3rMaRKuDQ9uExQU+PJpA" Cc: David Woodhouse , Steve Deiters , linuxppc-dev@lists.ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , --=-3rMaRKuDQ9uExQU+PJpA Content-Type: text/plain; charset=us-ascii; DelSp=Yes; Format=Flowed Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Am 08.07.10 17:22 schrieb(en) Grant Likely: >> Just out of curiousity, what configuration might cause a byte-wise align= ment not to work? >=20 > Can't remember the register configuration, but I worked on one project wh= ere this was the case. In hindsight, it was probably a mis-configuration o= f the localbus CS for the particular device. Not sure if you're thinking of this configuration, but if you attach a devi= ce in 16-bit mode (i.e. 16 data lines) to the LPB, byte writes simply don't= work. I ran into that problem as I have a nvram attached this way to a 52= 00b. Using the device as mtd-ram with a jffs2 file system on it I also som= etimes saw corruption after a write. I had a patch for that last year, but it was actually badly crafted (see ). I s= till use the mpc52xx_memcpy2lpb16() function somewhere in my current code w= hich is actually an ugly hack (but it works...). Actually, this is something which might need closer attention - and maybe s= ome support in the device tree indicating which read or write width a devic= e can accept? Best, Albrecht. --=-3rMaRKuDQ9uExQU+PJpA Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (GNU/Linux) iD8DBQBMNhuVn/9unNAn/9ERAi0RAKDENR7zwpsTxr9r1b0/ZxWGcGSDyACgn91T rGZbuFw1ANNVz5VR0T7c/Sc= =ISwg -----END PGP SIGNATURE----- --=-3rMaRKuDQ9uExQU+PJpA--