From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751836Ab1C2PjY (ORCPT ); Tue, 29 Mar 2011 11:39:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:23213 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994Ab1C2PjX (ORCPT ); Tue, 29 Mar 2011 11:39:23 -0400 Message-ID: <4D91FD1D.4070508@redhat.com> Date: Tue, 29 Mar 2011 12:39:09 -0300 From: Mauro Carvalho Chehab User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101208 Red Hat/3.1.7-3.el6_0 Lightning/1.0b2 Thunderbird/3.1.7 MIME-Version: 1.0 To: Borislav Petkov CC: "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 05/30] amd64_edac: Cleanup chipselect handling References: <1297358133-14320-1-git-send-email-bp@amd64.org> <1297358133-14320-6-git-send-email-bp@amd64.org> <4D91F31A.7040600@redhat.com> <20110329151643.GA22419@aftab> In-Reply-To: <20110329151643.GA22419@aftab> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em 29-03-2011 12:16, Borislav Petkov escreveu: > On Tue, Mar 29, 2011 at 10:56:26AM -0400, Mauro Carvalho Chehab wrote: >> Em 10-02-2011 15:15, Borislav Petkov escreveu: >>> From: Borislav Petkov >>> >>> Add a struct representing the DRAM chip select base/limit register >>> pairs. Concentrate all CS handling in a single function. Also, add CS >>> looping macros for cleaner, more readable code. While at it, adjust code >>> to F15h. Finally, do smaller macro names cleanups (remove family names >>> from register macros) and debug messages clarification. >>> >>> No functional change. >>> >>> Signed-off-by: Borislav Petkov >> >> Hi Borislav, >> >>> --- a/drivers/edac/amd64_edac.h >>> +++ b/drivers/edac/amd64_edac.h >>> @@ -160,6 +160,14 @@ >>> #define OFF false >>> >>> /* >>> + * Create a contiguous bitmask starting at bit position @lo and ending at >>> + * position @hi. For example >>> + * >>> + * GENMASK(21, 39) gives us the 64bit vector 0x000000ffffe00000. >>> + */ >>> +#define GENMASK(lo, hi) (((1ULL << ((hi) - (lo) + 1)) - 1) << (lo)) >>> + >> >> This is a nice macro that could be useful outside amd64. It is probably a good >> idea to move it to include/linux/bitops.h. > > I'd suggest rather if you want to use it in > EDAC. But if we have more users, I don't have a problem with putting > it there (or somewhere else generic enough if people have a better > suggestion). Yeah, other edac drivers could benefit of using it, and also could benefit on a variant that would do an AND operation and shift it, something like (untested): /* * Create a contiguous bitmask starting at bit position @lo and ending at * position @hi. For example * * APPLY_BITMASK(v, 21, 39) will return the result of: * (v & 0x000000ffffe00000) >> 21 */ #define APPLY_BITMASK(v, lo, hi) (((v) & ((1ULL << ((hi) - (lo) + 1)) - 1) << (lo)) >> (lo)) Almost all edac drivers do something like the above, for example, to get DIMM rows/cols/banks, etc. Probably, the most complex part is to find a nice name for it ;) Yet, I think non-edac drivers could also benefit of such macro, and, as this is not edac-specific, I think it would be better to add it at bitops.h. Cheers, Mauro