Re: [PATCH 2/5] arm64, thunder: Add initial dts for Cavium Thunder SoC

[Robert Richter]

On 28.08.14 09:31:43, Olof Johansson wrote:
> On Thu, Aug 28, 2014 at 9:25 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> > On Thu, Aug 28, 2014 at 05:15:56PM +0100, Robert Richter wrote:
> >> Olof,
> >>
> >> On 30.07.14 11:14:23, Olof Johansson wrote:
> >> > On Wed, Jul 30, 2014 at 8:06 AM, Robert Richter <rric@xxxxxxxxxx> wrote:
> >> > > From: Radha Mohan Chintakuntla <rchintakuntla@xxxxxxxxxx>
> >> > >
> >> > > Add initial device tree nodes for Cavium Thunder SoCs with support of
> >> > > 48 cores and gicv3. The dts file requires further changes, esp. for
> >> > > pci, gicv3-its and smmu. This changes will be added later together
> >> > > with the device drivers.
> >> > >
> >> > > Signed-off-by: Radha Mohan Chintakuntla <rchintakuntla@xxxxxxxxxx>
> >> > > Signed-off-by: Robert Richter <rrichter@xxxxxxxxxx>
> >> > > ---
> >> > >  arch/arm64/boot/dts/Makefile         |   1 +
> >> > >  arch/arm64/boot/dts/thunder-88xx.dts | 387 +++++++++++++++++++++++++++++++++++
> >> > >  2 files changed, 388 insertions(+)
> >> > >  create mode 100644 arch/arm64/boot/dts/thunder-88xx.dts
> >> > >
> >> > > diff --git a/arch/arm64/boot/dts/Makefile b/arch/arm64/boot/dts/Makefile
> >> > > index c52bdb051f66..f8001a62029c 100644
> >> > > --- a/arch/arm64/boot/dts/Makefile
> >> > > +++ b/arch/arm64/boot/dts/Makefile
> >> > > @@ -1,3 +1,4 @@
> >> > > +dtb-$(CONFIG_ARCH_THUNDER) += thunder-88xx.dtb
> >> > >  dtb-$(CONFIG_ARCH_VEXPRESS) += rtsm_ve-aemv8a.dtb foundation-v8.dtb
> >> > >  dtb-$(CONFIG_ARCH_XGENE) += apm-mustang.dtb
> >> >
> >> > Oh, and:
> >> >
> >> > Let's fix the mistake we made on 32-bit here (that we can't undo
> >> > unless we move all dts files now, which is too much churn), and put
> >> > each SoC vendor in its own subdirectory.
> >> >
> >> > So, please add a arch/arm64/boot/dts/cavium/ directory, add a Makefile
> >> > and the dts there.
> >> >
> >> > We should move vexpress under arm/   and xgene under apm/ too.
> >>
> >> I was looking into this. It turned out that this would introduce more
> >> pain than it solves. The problem with introducing vendor subdirs for
> >> .dts files is that this will require also subdirs for .dtb files to
> >> avoid name conflicts. This means that dtb files are no longer in a
> >> single directory. Current build scripts and makefiles rely on this.
> >> E.g.:
> >>
> >>  scripts/Makefile.lib:$(obj)/%.dtb.S: $(obj)/%.dtb
> >>
> >> Thus, the introduction of vendor subdirs is not easy to implement and
> >> may break existing workflows. Also, no other arch has vendor subdirs.
> >>
> >> A solution would be to have a naming scheme for dts files which
> >> requires the vendor in the file name, such as cavium-thunder-88xx.dtb.
> >> Though, these long names may look a bit ugly.
> >>
> >> Hmm... Any thoughts?
> >
> > That would make it possible to search, but the number of files in one
> > place might become somewhat overwelming (which I believe was Olof's
> > concern).
> >
> > Olof, thoughts?
> 
> Yeah, on 32 bit we've got an ever-growing and very large directory
> today that is becoming a headache. Carving it up in directories to
> reduce plain directory size would come a long way.
> 
> I think we would catch name conflicts quickly with the automatic
> builders we have today -- and it's likely that the files will have a
> platform prefix anyway so it shouldn't be a big issue. I think we can
> live with that.

So you mean, having the source files with subdirectories, but the dtb
files in a single obj dir?

-Robert
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