On 07.12.2015 20:03, Mark Rutland wrote:
On Mon, Dec 07, 2015 at 06:49:43PM +0000, Sudeep Holla wrote:
On 07/12/15 18:24, Geert Uytterhoeven wrote:
+ L2_CA57: cache-controller@0 {
+ compatible = "cache";
+ arm,data-latency = <4 4 1>;
+ arm,tag-latency = <3 3 3>;
Interesting, only PL2xx/3xx cache controller driver reads this from the
DT and configures the controller. The integrated L2 found in
A15/A7/A57/A53 needs doesn't make use of these values from the DT.
These properties seem to be from l2cc.txt, which really only corresponds
to PL210/PL220/PL310 (and variants) and isn't as generic as it sounds.
I don't see that these are necessary at all.
What's about a documentation patch like [1], then?
For what is the arm64 dts entry
cpu@0 {
...
next-level-cache = <&L2_0>;
};
L2_0: l2-cache0 {
compatible = "cache";
};
good for at all, then?
Best regards
Dirk
[1]
diff --git a/Documentation/devicetree/bindings/arm/l2cc.txt
b/Documentation/devicetree/bindings/arm/l2cc.txt
index 06c88a4..f687aed 100644
--- a/Documentation/devicetree/bindings/arm/l2cc.txt
+++ b/Documentation/devicetree/bindings/arm/l2cc.txt
@@ -1,12 +1,18 @@
* ARM L2 Cache Controller
-ARM cores often have a separate level 2 cache controller. There are
various
+ARM 32-bit cores often have a separate level 2 cache controller.
There are various
implementations of the L2 cache controller with compatible
programming models.
Some of the properties that are just prefixed "cache-*" are taken
from section
3.7.3 of the ePAPR v1.1 specification which can be found at:
https://www.power.org/wp-content/uploads/2012/06/Power_ePAPR_APPROVED_v1.1.pdf
-The ARM L2 cache representation in the device tree should be done as
follows:
+ARM 64-bit cores (e.g. A15/A7/A57/A53) have an integrated level 2
cache which
+doesn't make use of any values from the kernel device tree. There is no
+L2 cache configuration done in the kernel. The L2 cache is assumed to be
+preconfigured by early secure boot code.
+
+The ARM L2 cache representation for 32-bit cores in the device tree
should be done
+as follows:
Required properties:
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