Return-path: Received: from 80-190-117-144.ip-home.de ([80.190.117.144]:51454 "EHLO bu3sch.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752303Ab1DGHzB (ORCPT ); Thu, 7 Apr 2011 03:55:01 -0400 Subject: Re: [RFC][PATCH] bcmai: introduce AI driver From: Michael =?ISO-8859-1?Q?B=FCsch?= To: =?UTF-8?Q?Rafa=C5=82_Mi=C5=82ecki?= Cc: George Kashperko , Arnd Bergmann , Russell King , "linux-wireless@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "b43-dev@lists.infradead.org" , Arend van Spriel , linuxdriverproject , "linux-arm-kernel@lists.infradead.org" , Larry Finger In-Reply-To: (sfid-20110406_205435_519066_856A6627) References: <1302033463-1846-1-git-send-email-zajec5@gmail.com> <1302123428.20093.6.camel@maggie> <1302124112.20093.11.camel@maggie> <1302124737.27258.7.camel@dev.znau.edu.ua> <1302134429.27258.32.camel@dev.znau.edu.ua> (sfid-20110406_205435_519066_856A6627) Content-Type: text/plain; charset="UTF-8" Date: Thu, 07 Apr 2011 09:54:46 +0200 Message-ID: <1302162886.10725.4.camel@maggie> Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, 2011-04-07 at 02:54 +0200, Rafał Miłecki wrote: > W dniu 7 kwietnia 2011 02:00 użytkownik George Kashperko > napisał: > > For PCI function description take a look at PCI specs or PCI > > configuration space description (e. g. > > http://en.wikipedia.org/wiki/PCI_configuration_space) > > > > Sorry for missleading short-ups, w11 - bcm80211 core, under two-head I > > mean ssb/axi with two functional cores on same interconnect (like w11 > > +w11, not a lot of these exists I guess). Also there were some b43+b44 > > on single PCI ssb host and those where implemented as ssb interconnect > > on multifunctional PCI host therefore providing separate access windows > > for each function. > > > > Might I mussunderstood something (its late night here at my place) when > > you where talking about using coreswitching involved for two drivers > > therefore I remembered about those functions. Seems now you were talking > > about chipcommon+b43 access sharing same window. > > > > As for core switching requirments for earlier SSB interconnects on PCI > > hosts where there were no direct chipcommon access, that one can be > > accomplished without spin_lock/mutex for b43 or b44 cores with proper > > bus design. > > > > AXI doesn't need spinlocks/mutexes as both chipcommon and pci bridge are > > available directly and b43 will be the only one requiring window access. > > Ahh, so while talking about 4 windows, I guess you counted fixes > windows as well. That would be right, matching my knowledge. > > When asking question about amount of cores we may want to use > simultaneously I didn't think about ChipCommon or PCIe. The real > problem would be to support for example two 802.11 cores and one > ethernet core at the same time. That gives us 3 cores while we have > only 2 sliding windows. Would that really be a problem? Think of it. This combination will only be available on embedded devices. But do we have windows on embedded devices? I guess not. If AXI is similar to SSB, the MMIO of all cores will always be mapped. So accesses can be done without switch or lock. I do really think that engineers at broadcom are clever enough to design a hardware that does not require expensive window sliding all the time while operating. -- Greetings Michael.