Thread (40 messages) 40 messages, 12 authors, 2014-09-14

[PATCH 11/14] arm64: dts: Add initial device tree support for EXYNOS7

From: robh@kernel.org (Rob Herring)
Date: 2014-08-28 17:54:11
Also in: linux-devicetree, linux-samsung-soc

On Thu, Aug 28, 2014 at 12:19 PM, Olof Johansson [off-list ref] wrote:
On Thu, Aug 28, 2014 at 10:03 AM, Mark Rutland [off-list ref] wrote:
quoted
On Thu, Aug 28, 2014 at 05:28:22PM +0100, Olof Johansson wrote:
quoted
On Thu, Aug 28, 2014 at 2:48 AM, Mark Rutland [off-list ref] wrote:
quoted
Hi,
quoted
quoted
+   cpus {
+           #address-cells = <2>;
+           #size-cells = <0>;
Why size-cells=2? Can you not fit a cpuid in 32 bits?
As of commit 72aea393a2e7 (arm64: smp: honour #address-size when parsing
CPU reg property) Linux can handle single-cell cpu node reg entries
where /cpus/#address-cells = <1>.

I can't make any guarantees about other code (e.g. bootloaders) which
might try to do things with cpu nodes, YMMV.
Ok. If address-cells is kept at 2 the unit address needs to be changed
to "0,0". So one or the other has to be changed.
I'm happy either way.

I'm not sure the rest of the tree had "0," prefixes on all of the
unit-addresses for 64-bit addresses that were under 4GB, and I'm not
sure that existing dts consistently do that either.

Do we want to enforce that for all 64-bit unit-addresses?
Yeah, I believe that's the only valid format for a 2-address-cell unit address.
But we don't do leading 0's anywhere else like single cell unit
addresses. Buses expressed with ranges and offsets are one example.
Also, I2C addresses have a 32-bit size in DT yet are only 8-bit and we
don't do leading zero's there.

Rob
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