From mboxrd@z Thu Jan 1 00:00:00 1970 From: York Sun Date: Thu, 26 Sep 2013 12:48:31 -0700 Subject: [U-Boot] When to create a SoC directory for ARM In-Reply-To: References: <1380223392.24959.275.camel@snotra.buserror.net> Message-ID: <52448F8F.9080604@freescale.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 09/26/2013 12:46 PM, Sharma Bhupesh-B45370 wrote: > >> -----Original Message----- >> From: u-boot-bounces at lists.denx.de [mailto:u-boot-bounces at lists.denx.de] >> On Behalf Of Scott Wood >> Sent: Friday, September 27, 2013 12:53 AM >> To: FengHua >> Cc: trini; sun york-R58495; u-boot >> Subject: Re: [U-Boot] When to create a SoC directory for ARM >> >> On Thu, 2013-09-26 at 13:23 +0800, FengHua wrote: >>>> Date: Wed, 25 Sep 2013 20:10:13 -0500 >>>> From: Scott Wood >>>> Subject: Re: [U-Boot] When to create a SoC directory for ARM >>>> To: sun york-R58495 >>>> Cc: Rini , Wood Scott-B07421 , >>>> "u-boot at lists.denx.de" , Tom >>>> Message-ID: <1380157813.24959.237.camel@snotra.buserror.net> >>>> Content-Type: text/plain; charset="UTF-8" >>>> On Wed, 2013-09-25 at 20:04 -0500, sun york-R58495 wrote: >>>>> On Sep 25, 2013, at 4:52 PM, Scott Wood wrote: >>>>> >>>>>> On Wed, 2013-09-25 at 16:30 -0700, York Sun wrote: >>>>>>> Dear Wolfgang, >>>>>>> >>>>>>> I failed to find the guideline, here is my question. Pardon me >>>>>>> if this is a dump question as I am still new to ARM. >>>>>>> >>>>>>> As David Feng post his patch set to add ARMv8 support, I am >>>>>>> trying to enable it for Freescale implementation. Let's name it >>>>>>> as LS2 for this discussion. I am thinking to reuse as much as >>>>>>> possible for existing codes, which include copying some header >>>>>>> files from powerpc partially. I noticed the SoC field in >>>>>>> boards.cfg file and I am wondering how to use it effectively. I >>>>>>> want to put LS2 specific headers to >>>>>>> arch/arm/include/asm/arch-ls2. Do I need to copy all files from >>>>>>> arch/arm/include/asm/arch-armv8/? There aren't many but I see >>>>>>> mmu.h is included in start.S. I have been searching case like >> this in ARMv7 but didn't see shared header file (maybe I missed it). >> Please advise. >>>>>> >>>>>> LS2 is (or perhaps more accurately, contains) an implementation >>>>>> of ARMv8, so you should be using arch-armv8 rather than copying >> it. >>>>> >>>>> True. But I guess LS2 won't be the only "LS" Freescale is going to >>>>> make. Where is the best place to put the header file for chassis >>>>> related registers, like CCSR we have for mpc8xxx. >>>> Anything that isn't deeply tied to the ARM architecture should >>>> probably just go in include/. >>>>> I am thinking the >>>>> best place is arch/arm/include/asm/ls2 (or a better name). Like >>>>> other >>>>> ARMv7 variants, I am thinking to put ls2 under arch/arm/cpu/armv8/ >>>>> as well, to host LS-specific code. >>> >>>> Likewise, if it's specifically tied to armv8 it should go in >>>> arch/arm/include/asm/arch-armv8, but I'm not sure what would be tied >>>> to both armv8 and ls2. Most likely anything LS-specific that needs >>>> to go under arch/arm/ should go somewhere like >>>> arch/arm/include/asm/ls/ (similar to arch/arm/include/asm/imx- >> common). >>> >>>> -Scott >>> all SOC specific include file should be in >>> arch/arm/include/asm/arch-SOC/ or some common directory(like >>> include/asm/imx-common). Currently, u-boot only link SOC >>> specific(arch-SOC) include directory. >>> You could touch a mmu.h file in arch/arm/include/asm/arch-ls2/ and >>> include arch/arm/include/asm/arch-armv8/mmu.h. >>> or move arch-armv8/mmu.h to arch/arm/include/asm/ to make it as a >>> generic file. >>> Maybe we should distinguish architecture specific include directory >>> and SOC specific include directory. >> >> Is the XXX arch-XXX supposed to be an SoC family or a CPU >> family/architectutre? >> > > Usually in 'arch/arm/include/asm' we have both: > - arch-armv7 (Arch specific. Houses stuff common to ARMv7 CPU, e.g. Global timer, SP805 WDT..) > - arch-mx6 (SoC family specific. Houses stuff like SoC specific IOMUX pads..) > > We should have something similar for LayerScape. > > If you look closely, you will find arch-armv7 and its sub-arch including am33xx, at91, exynos, etc. York