From mboxrd@z Thu Jan 1 00:00:00 1970 From: Magnus Damm Date: Thu, 17 Mar 2011 07:10:41 +0000 Subject: Re: SH Core Linux 20110317 Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: linux-sh@vger.kernel.org On Thu, Mar 17, 2011 at 3:56 PM, Mike Frysinger wrote: > On Thursday, March 17, 2011 02:40:01 Magnus Damm wrote: >> This is the first public release of SH Core Linux, version 20110317. >> >> SH Core Linux brings the Linux to the SH core included in sh7372 - >> running in parallel with the ARM core. >> >> Many modern SoCs contain multiple CPU cores in asymmetric >> multiprocessing configurations. These asymmetric CPU configurations >> often run multiple operating system instances; sometimes multiple >> instances of Linux and sometimes Linux on the main CPU and some >> customized software on the other CPU cores. Asymmetric CPU >> configurations are different from symmetric multiprocessing >> configurations which make use of a single Linux kernel together with >> SMP to support multiple processor cores. To make things even more >> complicated, come SoCs are configured to have some CPU cores operating >> in SMP mode, and others in AMP. > > interesting. =A0we've been banging on similar issues with multiple Blackf= ins. > we've got an ICC (inter core communication) driver going atm. =A0but the > protocol isnt limited to Blackfins ... we've made sure to design it so th= at > any other processor type can work, as well as any operating system. Yeah, this problem isn't limited to ARM, SH or Renesas. I agree that we all want to support multiple operating systems, but I believe this has already been done by the virtualization/enterprise community with their paravirtualized drivers using Virtio. >> This SH Core Linux prototype is written for the sh7372 SoC from >> Renesas. The sh7372 contains one ARM Cortex-A8 and one SH4AL-DSP core. >> This release includes all that is needed to run two instances of >> Linux; one on the ARM core and one on the SH core. The ARM core is the >> main SoC processor which runs a user space program to control the SH >> core. The SH core does not make use of any special hardware except a >> mailbox interface where Virtio serves as a communication link. > > so this implementation isnt limited to Linux right ? I'm sure other people are using different operating systems on sh7372, but this SH Core Linux implementation is Linux-only. However, Virtio is not Linux-only. In other words, the SH Core Linux release in this thread is basically some SoC specific glue to get Virtio going for interprocess communication on sh7372. I see no reason why other vendors can't do the same. No need to invent your own drivers when we have fully working virtio drivers. > i think TI has been doing their own thing too ? =A0but they dont usually = try > hard to push back to mainline ... > > and then there's MCAPI ... Yeah, each vendor unfortunately has their own solution. The situation is similar to traditional embedded PM. > i wonder if there's some way we can centralize/focus efforts on the Linux= side > so each SoC vendor doesnt keep coming up with its own magic sauce to glue > worlds together. =A0i really dont see this as being a useful area for eve= ryone > to "innovate" on their own. =A0the advantage to being the first one into > mainline is that everyone else will have to migrate to it :). > > perhaps start a list on vger.kernel.org and a wiki on wiki.kernel.org ? I believe the answer to all this is Virtio, but I'm not sure if everyone will agree with me. =3D) Thanks, / magnus