From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mo-p07-ob.rzone.de (mo-p07-ob.rzone.de [81.169.146.189]) by ozlabs.org (Postfix) with ESMTP id 7F63C67A3B for ; Mon, 20 Nov 2006 23:10:14 +1100 (EST) Date: Mon, 20 Nov 2006 12:54:32 +0100 (MET) From: Stefan Roese To: Alan Subject: Re: [PATCH] serial: Use real irq on UART0 (IRQ = 0) on PPC4xx systems References: <200611201200.36780.ml@stefan-roese.de> <20061120114248.60bb0869@localhost.localdomain> In-Reply-To: <20061120114248.60bb0869@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Message-Id: <200611201255.37754.ml@stefan-roese.de> Cc: linux-kernel@vger.kernel.org, linuxppc-embedded@ozlabs.org List-Id: Linux on Embedded PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Monday 20 November 2006 12:42, Alan wrote: > On Mon, 20 Nov 2006 12:00:36 +0100 > > Stefan Roese wrote: > > This patch fixes a problem seen on multiple 4xx platforms, where > > the UART0 interrupt number is 0. The macro "is_real_interrupt" lead > > on those systems to not use an real interrupt but the timer based > > implementation. > > NAK. I knew it. ;-) > Zero means "no interrupt" in the Linux space. If you have a physical IRQ > 0 remap it to a convenient number (eg map IRQ's + 1, or stick it on the > end). The logical and physical IRQ numbering in Linux don't have to match > up - and given some platforms have IRQ numbering per bus and the like > clearly doesn't in many cases. Let's see, if I got this right. You mean that on such a platform, where 0 is a valid physical IRQ, we should assign another value as virtual IRQ number (not 0 and not -1 of course). And then the platform "pic" implementation should take care of the remapping of these virtual IRQ numbers to the physical numbers. Correct? Best regards, Stefan