Re: [PATCH v6 9/9] ARM: vexpress: Add Device Tree for V2P-CA15 core tile (TC1 variant)

On 19/01/12 14:51, Pawel Moll wrote:

On Thu, 2012-01-19 at 14:01 +0000, Rob Herring wrote:

quoted

On 01/19/2012 07:43 AM, Pawel Moll wrote:

quoted

On Thu, 2012-01-19 at 13:34 +0000, Rob Herring wrote:

quoted

quoted

You're right - the skeleton.dtsi contains "memory" mode... Funnily
enough originally I was using that name, but then Rob Herring suggested
changing it to @80000000, which seemed reasonable.

Now I wonder - is the "memory" node special and should not contain
"@address", or the skelton shouldn't contain the empty "memory" node...

Hummm... I guess you should just use "memory" if you are using
skeleton.dtsi.

Well, I don't mind _not_ using skeleton, but I had an impression the
general policy was to use it?

Either way is fine. I don't really think it buys you much.

Ok, /include/ "skeleton.dtsi" is gone then :-)

The problem wasn't with including skeleton.dtsi.  With
CONFIG_ARM_ATAG_DTB_COMPAT the zImage decompressor modifies the appended
DTB using information from the ATAGs (see atags_to_fdt()).

If there's an ATAG giving the amount of RAM the DTB's "memory" node is
replaced with a new one.  Since the vexpress DTBs don't have a "memory"
node it's added and the DTB ends up with two nodes describing memory.

I don't expect any real production vexpress system to use this config
options -- we're using it now when running as a guest under Xen because
Xen doesn't (yet) support device tree and we're using ATAGs to tell the
guest how much RAM it's been allocated.

David

On Thu, 2012-01-19 at 17:00 +0000, David Vrabel wrote:

The problem wasn't with including skeleton.dtsi.  

Including as it is creates two device_type="memory" nodes, one with
regs=<0 0>, which is definitely wrong.

With
CONFIG_ARM_ATAG_DTB_COMPAT the zImage decompressor modifies the appended
DTB using information from the ATAGs (see atags_to_fdt()).

If there's an ATAG giving the amount of RAM the DTB's "memory" node is
replaced with a new one.  Since the vexpress DTBs don't have a "memory"
node it's added and the DTB ends up with two nodes describing memory.

The "memory at address" node name is in my opinion perfectly legal - p. 3.4
of the DT spec says "The name component of the node name (see 2.2.1)
shall be memory.". So the decompressor code may be wrong in looking for
adress-less "memory" node...

One way or the other, I'll get this fixed.

Thanks for letting me know!

Pawe?

On Thu, 2012-01-19 at 17:00 +0000, David Vrabel wrote:

quoted

Ok, /include/ "skeleton.dtsi" is gone then :-)

The problem wasn't with including skeleton.dtsi.  With
CONFIG_ARM_ATAG_DTB_COMPAT the zImage decompressor modifies the appended
DTB using information from the ATAGs (see atags_to_fdt()).

If there's an ATAG giving the amount of RAM the DTB's "memory" node is
replaced with a new one.  Since the vexpress DTBs don't have a "memory"
node it's added and the DTB ends up with two nodes describing memory.

As it turned out it was just the "skeleton.dtsi" problem after all - I
mean the fact that there where two device_type="memory" nodes in the
tree.

The decompressor's setprop()
(arch/arm/boot/compressed/atags_to_fdt.c:12) uses libfdt's
fdt_setprop(), which correctly ignores the "@00000000" component of the
node name and sets the reg property as expected. So as long as there is
exactly one "memory[@address]" node in the tree,
CONFIG_ARM_ATAG_DTB_COMPAT is happy.

I will remove the /include/ from the dts files for VE (see below) in the
v3.3-rc1 based series.

Thanks for spotting this!

Pawe?

diff --git a/arch/arm/boot/dts/vexpress-v2p-ca15-tc1.dts b/arch/arm/boot/dts/vexpress-v2p-ca15-tc1.dts
index 02cada5..2a690f2 100644
--- a/arch/arm/boot/dts/vexpress-v2p-ca15-tc1.dts
+++ b/arch/arm/boot/dts/vexpress-v2p-ca15-tc1.dts

@@ -9,13 +9,15 @@
 
 /dts-v1/;
 
-/include/ "skeleton.dtsi"
-
 / {
 	model = "V2P-CA15";
 	arm,hbi = <0x237>;
 	compatible = "arm,vexpress,v2p-ca15,tc1", "arm,vexpress,v2p-ca15", "arm,vexpress";
 	interrupt-parent = <&gic>;
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	chosen { };
 
 	aliases {
 		serial0 = &v2m_serial0;

diff --git a/arch/arm/boot/dts/vexpress-v2p-ca5s.dts b/arch/arm/boot/dts/vexpress-v2p-ca5s.dts
index da26a13..d4c5322 100644
--- a/arch/arm/boot/dts/vexpress-v2p-ca5s.dts
+++ b/arch/arm/boot/dts/vexpress-v2p-ca5s.dts

@@ -9,13 +9,15 @@
 
 /dts-v1/;
 
-/include/ "skeleton.dtsi"
-
 / {
 	model = "V2P-CA5s";
 	arm,hbi = <0x225>;
 	compatible = "arm,vexpress,v2p-ca5s", "arm,vexpress";
 	interrupt-parent = <&gic>;
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	chosen { };
 
 	aliases {
 		serial0 = &v2m_serial0;

diff --git a/arch/arm/boot/dts/vexpress-v2p-ca9.dts b/arch/arm/boot/dts/vexpress-v2p-ca9.dts
index 84542e7..5d90ce5 100644
--- a/arch/arm/boot/dts/vexpress-v2p-ca9.dts
+++ b/arch/arm/boot/dts/vexpress-v2p-ca9.dts

@@ -9,13 +9,15 @@
 
 /dts-v1/;
 
-/include/ "skeleton.dtsi"
-
 / {
 	model = "V2P-CA9";
 	arm,hbi = <0x191>;
 	compatible = "arm,vexpress,v2p-ca9", "arm,vexpress";
 	interrupt-parent = <&gic>;
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	chosen { };
 
 	aliases {
 		serial0 = &v2m_serial0;