[U-Boot] When to create a SoC directory for ARM

[Scott Wood]

On Thu, 2013-09-26 at 12:48 -0700, York Sun wrote:
> 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 <scottwood at freescale.com>
> >>>> Subject: Re: [U-Boot] When to create a SoC directory for ARM
> >>>> To: sun york-R58495 <R58495 at freescale.com>
> >>>> Cc: Rini <trini at ti.com>, Wood Scott-B07421 <B07421 at freescale.com>,
> >>>> 	"u-boot at lists.denx.de" <u-boot at lists.denx.de>, Tom
> >>>> Message-ID: <1380157813.24959.237.camel at 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..)

Which one does "#inculde <asm/arch/foo.h>" refer to?

-Scott