From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753521Ab1KOIK6 (ORCPT ); Tue, 15 Nov 2011 03:10:58 -0500 Received: from mailgw9.se.ericsson.net ([193.180.251.57]:48688 "EHLO mailgw9.se.ericsson.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752851Ab1KOIK4 (ORCPT ); Tue, 15 Nov 2011 03:10:56 -0500 X-AuditID: c1b4fb39-b7b3eae00000252a-61-4ec21e8eda37 Message-ID: <4EC21E8E.5050003@ericsson.com> Date: Tue, 15 Nov 2011 09:10:54 +0100 From: =?UTF-8?B?TmlrbGFzIFPDtmRlcmx1bmQ=?= User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:8.0) Gecko/20111108 Thunderbird/8.0 MIME-Version: 1.0 To: Borislav Petkov CC: Tony Luck , "dougthompson@xmission.com" , "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] amd64_edac: Fix K8 revD and later chip select sizes References: <1320849178-23340-1-git-send-email-niklas.soderlund@ericsson.com> <20111109144258.GD30472@aftab> <4EBA98A1.90902@ericsson.com> <20111109203546.GI14181@aftab> <20111109210052.GJ14181@aftab> <20111114165459.GA29762@aftab> In-Reply-To: <20111114165459.GA29762@aftab> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 14 Nov 2011 05:54:59 PM CET, Borislav Petkov wrote: > > Fix DRAM chip select sizes calculation for K8, revisions D and E. > > Reported-by: Niklas Söderlund Link: http://lkml.kernel.org/r/1320849178-23340-1-git-send-email-niklas.soderlund@ericsson.com > Signed-off-by: Borislav Petkov > --- > > @Niklas: would you please verify this patch fixes your issue? > > Thanks. > > drivers/edac/amd64_edac.c | 32 ++++++++++++++++++++++++++++---- > 1 files changed, 28 insertions(+), 4 deletions(-) > > diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c > index c9eee6d..6a83d49 100644 > --- a/drivers/edac/amd64_edac.c > +++ b/drivers/edac/amd64_edac.c > @@ -1132,12 +1132,36 @@ static int k8_dbam_to_chip_select(struct amd64_pvt *pvt, u8 dct, > return ddr2_cs_size(cs_mode, dclr& WIDTH_128); > } > else if (pvt->ext_model>= K8_REV_D) { > + unsigned diff; > WARN_ON(cs_mode> 10); > > - if (cs_mode == 3 || cs_mode == 8) > - return 32<< (cs_mode - 1); > - else > - return 32<< cs_mode; > + /* > + * the below calculation, besides trying to win an obfuscated C > + * contest, maps cs_mode values to DIMM chip select sizes. The > + * mappings are: > + * > + * cs_mode CS size (mb) > + * ======= ============ > + * 0 32 > + * 1 64 > + * 2 128 > + * 3 128 > + * 4 256 > + * 5 512 > + * 6 256 > + * 7 512 > + * 8 1024 > + * 9 1024 > + * 10 2048 > + * > + * Basically, it calculates a value with which to shift the > + * smallest CS size of 32MB. > + * > + * ddr[23]_cs_size have a similar purpose. > + */ > + diff = cs_mode/3 + (unsigned)(cs_mode> 5); > + > + return 32<< (cs_mode - diff); > } > else { > WARN_ON(cs_mode> 6); Hi Borislav, Yes the patch fixes my problem, but it truly is obfuscated C. Thanks // Niklas