From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Christophe PLAGNIOL-VILLARD Subject: Re: [GIT PULL] omap changes for v2.6.39 merge window Date: Thu, 31 Mar 2011 14:23:08 +0200 Message-ID: <20110331122308.GG7420@game.jcrosoft.org> References: <20110331105440.42692165@lxorguk.ukuu.org.uk> <20110331105000.GC14323@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20110331105000.GC14323@n2100.arm.linux.org.uk> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Russell King - ARM Linux Cc: david@lang.hm, Arnd Bergmann , Nicolas Pitre , Tony Lindgren , Catalin Marinas , lkml , Linus Torvalds , linux-arm-kernel@lists.infradead.org, David Brown , linux-omap@vger.kernel.org, Dave Airlie , Alan Cox List-Id: linux-omap@vger.kernel.org On 11:50 Thu 31 Mar , Russell King - ARM Linux wrote: > On Thu, Mar 31, 2011 at 10:54:40AM +0100, Alan Cox wrote: > > If I boot it on a current PC I'm booting on a multiprocessor system with > > different timers, totally different IRQ controllers, different keyboard > > controllers (USB), PCI Express, an IOMMU, NCQ SATA, ACPI, graphics > > running in shared host memory able to give/take pages from the host, > > extra instructions, etc etc > > > > And the same kernel boots just fine on both just fine. > > We've been there for a long time with ARM. Right from the start I had > a single kernel image which booted over a range of ARM CPUs and > platforms. > > As far as ARM CPU architectures go, today we can have a single kernel > image which covers ARMv3 to ARMv5, and a separate kernel image which > covers ARMv6 to ARMv7 including SMP and UP variants. The thing which > currently stops ARMv3 to ARMv7 all together is the different page table > layouts, the ASID tagging, the exclusive load/store support for cmpxchg > and other atomic operations, etc. As we can see a lots of people work on this, to now do not add thousand of boards but try to have only a few Personnaly I do it on at91 as example and will continue to try to have one board in the kernel with board information pass via Barebox, when it's possible. I think it's a common effort doen by the ARM Community and this will imply a lots of changesets. The work done by Linaro with the device tree will help a lot to simplify the pass of the information from the boot loader to the kernel. But we can already do it today. Best Regards, J.