From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jamie Lokier Subject: Re: Status of arch/arm in linux-next Date: Mon, 2 May 2011 00:02:13 +0100 Message-ID: <20110501230213.GG5832@shareable.org> References: <20110414094447.GA1611@n2100.arm.linux.org.uk> <20110421201455.GA18083@redhat.com> <201104261605.26791.arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <201104261605.26791.arnd@arndb.de> List-Id: 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: Arnd Bergmann Cc: Nicolas Pitre , Russell King - ARM Linux , Tony Lindgren , Linus Walleij , Mark Brown , cpufreq@vger.kernel.org, "Rafael J. Wysocki" , Dave Jones , linux-arm-kernel@lists.infradead.org Arnd Bergmann wrote: > On Thursday 21 April 2011, Nicolas Pitre wrote: > > > if there's commonality between some of the ARM arch drivers, why can't > > > there be a arch/arm/cpufreq/ dir for the shared code, and do everything there ? > > > > Because usually there isn't. "ARM" is just a CPU architecture, not a > > system architecture. Everything around the core is different from one > > vendor to the next. And when commonality exists it is much easier to > > deal with if it is close together. > > Exactly. To make matters worse, we are starting to see a number of vendors > that use multiple CPU architectures with the same I/O devices (e.g. Renesas, > Freescale, Xilinx, TI, ...). Not sure if any of these use the same cpufreq > register on more than one architecture, but it's quite likely to happen > at some point. Can't comment on in-tree SoCs, but out of tree (they use Linux but don't submit anything upstream as far as I can tell), Sigma Designs use ARM & MIPS CPU architectures, with the clock/timing registers, irq registers and more or less everything else being the same among them. -- Jamie From mboxrd@z Thu Jan 1 00:00:00 1970 From: jamie@shareable.org (Jamie Lokier) Date: Mon, 2 May 2011 00:02:13 +0100 Subject: Status of arch/arm in linux-next In-Reply-To: <201104261605.26791.arnd@arndb.de> References: <20110414094447.GA1611@n2100.arm.linux.org.uk> <20110421201455.GA18083@redhat.com> <201104261605.26791.arnd@arndb.de> Message-ID: <20110501230213.GG5832@shareable.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Arnd Bergmann wrote: > On Thursday 21 April 2011, Nicolas Pitre wrote: > > > if there's commonality between some of the ARM arch drivers, why can't > > > there be a arch/arm/cpufreq/ dir for the shared code, and do everything there ? > > > > Because usually there isn't. "ARM" is just a CPU architecture, not a > > system architecture. Everything around the core is different from one > > vendor to the next. And when commonality exists it is much easier to > > deal with if it is close together. > > Exactly. To make matters worse, we are starting to see a number of vendors > that use multiple CPU architectures with the same I/O devices (e.g. Renesas, > Freescale, Xilinx, TI, ...). Not sure if any of these use the same cpufreq > register on more than one architecture, but it's quite likely to happen > at some point. Can't comment on in-tree SoCs, but out of tree (they use Linux but don't submit anything upstream as far as I can tell), Sigma Designs use ARM & MIPS CPU architectures, with the clock/timing registers, irq registers and more or less everything else being the same among them. -- Jamie