From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from moutng.kundenserver.de ([212.227.126.188]:49167 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751081AbXB1AnD convert rfc822-to-8bit (ORCPT ); Tue, 27 Feb 2007 19:43:03 -0500 From: Arnd Bergmann Subject: Re: [RFC] killing the NR_IRQS arrays. Date: Wed, 28 Feb 2007 01:41:50 +0100 References: <1171844753.5644.174.camel@localhost.localdomain> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200702280141.51420.arnd@arndb.de> Sender: linux-arch-owner@vger.kernel.org To: "Eric W. Biederman" Cc: Benjamin Herrenschmidt , Arjan van de Ven , Ingo Molnar , linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Linus Torvalds , Andrew Morton , Andi Kleen , Alan Cox , Thomas Gleixner List-ID: On Tuesday 27 February 2007, Eric W. Biederman wrote: > * Add a variation of the API in interrupt.h that uses >   "struct irq *irq" instead of "unsigned int irq" >   >   Probably replacing request_irq with irq_request or something >   trivial like that. > >   This will need to touch all of different irq implementation back >   ends, but only very lightly. > > * Convert the generic irq code to use struct irq * everywhere it >   current uses "unsigned int irq". > > * Start on the conversions of drivers and subsystems picking on >   the easy ones first :) Introducing the irq_request() etc. functions that take a struct irq* instead of an int sounds good, but I'd hope we can avoid using those in device drivers and do a separate abstraction for each bus_type that deals with interrupts. I'm not sure if that's possible for each bus_type, but the ones I have worked with in the past should allow that: pci: each device/function has a unique irq, drivers need not know about it afaics. isa/pnp: numbers from 1 to 15 are the right abstraction here, that how isa has worked for ages. s390: got rid of irq numbers already ofw: an open firmware device can have a number of interrupts, but like PCI, the driver only needs to know things like 'first irq of this device', not how it's connected ps3: irqs are requested from the firmware for each device, this can happen under the covers. mmc, usb, phy, ieee1394: these already have a higl-level abstraction for interrupt events platform: dunno, probably these really should use the struct irq directly eisa, mca, pcmcia, zorro, ...: no idea, but possibly similar to PCI. Note that we can even start converting device drivers first, before moving away from irq numbers. A typical PCI driver should get somewhat simpler by the conversion, and when they are all converted, we can replace pci_dev->irq with a struct irq* under the covers. Arnd <><