[RFC] arm64: Add new cpu-return-addr device tree binding

Geoff Levand
2014-08-15T19:48:50Z

Add a new device tree binding cpu-return-addr. This binding is required for
all ARM v8 CPUs that have an "enable-method" property value of "spin-table". The
value is a 64 bit read-only physical address that secondary CPU execution will
transfer to upon CPU shutdown.

Signed-off-by: Geoff Levand <geoff@infradead.org>
---
Hi All,

We currently have no way for arm64 spin-table CPUs to re-enter the spin
table code, and some way to do so is needed to implement a hot-plug
cpu_die() for these CPUs.

I just wanted to get this binding patch out for review now. I have other
patches that implement the spin-table hot-plug in my kexec repo [1].

Please consider.

-Geoff

[1] https://git.linaro.org/people/geoff.levand/linux-kexec.git

Documentation/devicetree/bindings/arm/cpus.txt | 26 ++++++++++++++++++++++
Documentation/devicetree/bindings/arm/topology.txt | 16 +++++++++++++
2 files changed, 42 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
index 1fe72a0..24b98a9 100644
--- a/Documentation/devicetree/bindings/arm/cpus.txt
+++ b/Documentation/devicetree/bindings/arm/cpus.txt
@@ -201,6 +201,16 @@ nodes to be present and contain the properties described below.
property identifying a 64-bit zero-initialised
memory location.

+ - cpu-return-addr
+ Usage: required for all ARM v8 CPUs that have an "enable-method"
+ property value of "spin-table".
+ Value type: <prop-encoded-array>
+ Definition:
+ # On ARM v8 64-bit systems must be a two cell property.
+ The value is a 64 bit read-only physical address that
+ secondary CPU execution will transfer to upon CPU
+ shutdown.
+
- qcom,saw
Usage: required for systems that have an "enable-method"
property value of "qcom,kpss-acc-v1" or
@@ -285,6 +295,7 @@ cpus {
reg = <0x0 0x0>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 1 {
@@ -293,6 +304,7 @@ cpus {
reg = <0x0 0x1>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100 {
@@ -301,6 +313,7 @@ cpus {
reg = <0x0 0x100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 101 {
@@ -309,6 +322,7 @@ cpus {
reg = <0x0 0x101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 10000 {
@@ -317,6 +331,7 @@ cpus {
reg = <0x0 0x10000>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 10001 {
@@ -325,6 +340,7 @@ cpus {
reg = <0x0 0x10001>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 10100 {
@@ -333,6 +349,7 @@ cpus {
reg = <0x0 0x10100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 10101 {
@@ -341,6 +358,7 @@ cpus {
reg = <0x0 0x10101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100000000 {
@@ -349,6 +367,7 @@ cpus {
reg = <0x1 0x0>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100000001 {
@@ -357,6 +376,7 @@ cpus {
reg = <0x1 0x1>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100000100 {
@@ -365,6 +385,7 @@ cpus {
reg = <0x1 0x100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100000101 {
@@ -373,6 +394,7 @@ cpus {
reg = <0x1 0x101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100010000 {
@@ -381,6 +403,7 @@ cpus {
reg = <0x1 0x10000>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100010001 {
@@ -389,6 +412,7 @@ cpus {
reg = <0x1 0x10001>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100010100 {
@@ -397,6 +421,7 @@ cpus {
reg = <0x1 0x10100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

cpu at 100010101 {
@@ -405,6 +430,7 @@ cpus {
reg = <0x1 0x10101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};
};

diff --git a/Documentation/devicetree/bindings/arm/topology.txt b/Documentation/devicetree/bindings/arm/topology.txt
index 1061faf..29e2193 100644
--- a/Documentation/devicetree/bindings/arm/topology.txt
+++ b/Documentation/devicetree/bindings/arm/topology.txt
@@ -260,6 +260,7 @@ cpus {
reg = <0x0 0x0>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU1: cpu at 1 {
@@ -268,6 +269,7 @@ cpus {
reg = <0x0 0x1>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU2: cpu at 100 {
@@ -276,6 +278,7 @@ cpus {
reg = <0x0 0x100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU3: cpu at 101 {
@@ -284,6 +287,7 @@ cpus {
reg = <0x0 0x101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU4: cpu at 10000 {
@@ -292,6 +296,7 @@ cpus {
reg = <0x0 0x10000>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU5: cpu at 10001 {
@@ -300,6 +305,7 @@ cpus {
reg = <0x0 0x10001>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU6: cpu at 10100 {
@@ -308,6 +314,7 @@ cpus {
reg = <0x0 0x10100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU7: cpu at 10101 {
@@ -316,6 +323,7 @@ cpus {
reg = <0x0 0x10101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU8: cpu at 100000000 {
@@ -324,6 +332,7 @@ cpus {
reg = <0x1 0x0>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU9: cpu at 100000001 {
@@ -332,6 +341,7 @@ cpus {
reg = <0x1 0x1>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU10: cpu at 100000100 {
@@ -340,6 +350,7 @@ cpus {
reg = <0x1 0x100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU11: cpu at 100000101 {
@@ -348,6 +359,7 @@ cpus {
reg = <0x1 0x101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU12: cpu at 100010000 {
@@ -356,6 +368,7 @@ cpus {
reg = <0x1 0x10000>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU13: cpu at 100010001 {
@@ -364,6 +377,7 @@ cpus {
reg = <0x1 0x10001>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU14: cpu at 100010100 {
@@ -372,6 +386,7 @@ cpus {
reg = <0x1 0x10100>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};

CPU15: cpu at 100010101 {
@@ -380,6 +395,7 @@ cpus {
reg = <0x1 0x10101>;
enable-method = "spin-table";
cpu-release-addr = <0 0x20000000>;
+ cpu-return-addr = <0 0x20001000>
};
};

--
1.9.1