Messages in this thread |  | | From | Arnd Bergmann <> | Subject | Re: [PATCH] ARM: supplementing IO accessors with 64 bit capability | Date | Fri, 24 Oct 2014 12:37:33 +0200 |
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On Thursday 23 October 2014 16:15:19 Nicolas Pitre wrote: > On Thu, 23 Oct 2014, Russell King - ARM Linux wrote: > > > On Thu, Oct 23, 2014 at 03:47:32PM -0400, Nicolas Pitre wrote: > > > On Wed, 22 Oct 2014, Catalin Marinas wrote: > > > > > > > On Wed, Oct 22, 2014 at 05:06:23PM +0100, mathieu.poirier@linaro.org wrote: > > > > > +#if __LINUX_ARM_ARCH__ >= 5 > > > > > > > > My old ARMv5 book does not list LDRD/STRD. It looks like they only come > > > > with ARMv5TE. Are there any processors prior to this supported by the > > > > kernel? > > > > > > We still supports ARMv4 targets. > > > > > > As far as I know, all the ARMv5 targets we support are also TE capable. > > > > Not quite. We have ARM1020, which according to our proc-*.S files is > > only ARMv5T, not ARMv5TE.
Does this actually work when we are building with -march=armv5te?
The Makefile contains this line:
arch-$(CONFIG_CPU_32v5) =-D__LINUX_ARM_ARCH__=5 $(call cc-option,-march=armv5te,-march=armv4t)
which looks like it would break for ARM1020.
On a related note, I also wonder about this part:
tune-$(CONFIG_CPU_ARM946E) =$(call cc-option,-mtune=arm9e,-mtune=arm9tdmi) tune-$(CONFIG_CPU_ARM920T) =-mtune=arm9tdmi tune-$(CONFIG_CPU_ARM922T) =-mtune=arm9tdmi tune-$(CONFIG_CPU_ARM925T) =-mtune=arm9tdmi tune-$(CONFIG_CPU_ARM926T) =-mtune=arm9tdmi
I stumbled over this a while ago and couldn't figure it out. Does ARM926T actually exist, or is that a mistake that should actually be ARM926E?
If this is always ARM926E, shouldn't we build with -mtune=arm9e as we do for ARM946E?
> Oh well. Never saw such a beast in the field though.
The only ARM10 implementation aside from integrator/realview that I'm aware of is an ARM1026E based Conexant/Ikanos DSL modem SoC (CX94xxx), and that is of course ARMv5TE.
> Maybe to be on the very safe side, given that no ARMV5TE is likely to > need 64-bit IO accessors at this point, this could simply be > __LINUX_ARM_ARCH__ >= 6 instead.
Which drivers need that support anyway? We definitely need to ensure that we don't try to build them on architectures without this support when CONFIG_COMPILE_TEST is set.
Arnd
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