From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Mon, 13 Feb 2012 11:07:30 +0000 Subject: Question on ARM Cortex R4 support in Linux In-Reply-To: References: <20120213105313.GD4994@arm.com> Message-ID: <20120213110730.GA7375@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, Feb 13, 2012 at 10:59:50AM +0000, shiraz hashim wrote: > Hi Catalin, > > On Mon, Feb 13, 2012 at 4:23 PM, Catalin Marinas > wrote: > > On Mon, Feb 13, 2012 at 10:49:18AM +0000, shiraz hashim wrote: > >> We plan to use Linux on our Cortex R4 based SoC. > >> Can we use the latest Linux straight away or do we > >> require to add some support for it. > >> > >> I went through www.linux-arm.org/LinuxKernel/LinuxM3 > >> which describes Cortex M3 support in Linux but was not > >> able to find any information on M4. > > > > Do you mean M4 or R4 here? > > I am interested in R4 but was just thinking that M4 support can work > for R4 as well. M4 and R4 are completely different processor classes. R4 is supported pretty much by default in !MMU Linux as it's close to the A class (same exception model). The M class has a completely different exception model and it only supports the Thumb-2 instruction set. > >> Has anybody used it on Cortex R4 based platform ? > > > > In theory Linux support for R4 should just work (once CONFIG_MMU is > > disabled). I used to test it in the past regularly but not recently. > > Great. I was planning to use linux-3.2, I hope the support is there ? It's been there for years, but some bit-rotting may have occurred. -- Catalin