Added the lopper dts file to generate imagebuilder config from system-device-tree

Lopper parses the device tree for a "xen" label. It parses the sub nodes
to determine the DOM0_VCPUS, DOM0_MEM, NUM_DOMUS, DOMU_VCPUS[],
DOMU_MEM[] and DOMU_PASSTHROUGH_PATHS[]

As an example, consider the following snippet of system-device-tree

xen: domain@2 {
    compatible = "openamp,domain-v1","openamp,hypervisor-v1";
    cpus = <&cpus_a72 0x3 0x00000002>;
    memory = <0x0 0x500000 0x0 0x7fb00000>;

    dom0: domain@3 {
        compatible = "openamp,domain-v1","xen,domain-v2";
        cpus = <&cpus_a72 0x3 0x00000001>;
        memory = <0x0 0x501000 0x0 0x3faff000>;
    };

    linux1: domain@4 {
        compatible = "openamp,domain-v1","xen,domain-v2";
        cpus = <&cpus_a72 0x3 0x00000001>;
        memory = <0x0 0x501000 0x0 0x3faff000>;
        access = <&mmc0 0x0>;
    };

    linux2: domain@5 {
        compatible = "openamp,domain-v1","xen,domain-v2";
        cpus = <&cpus_a72 0x3 0x00000001>;
        memory = <0x0 0x40000000 0x0 0x40000000>;

        firewallconfig = <&linux1 1 0>;
    };
};

python3 _path_to_/lopper.py  -f --enhanced -i path_to_/lop-xen.dts  device-trees/system-device-tree-xen.dts > config

The contents of the 'config' will be as follows :-

NUM_DOMUS=2
DOM0_VCPUS = 2
DOM0_MEM = 1018
DOMU_VCPUS[0] = 2
DOMU_MEM[0] = 1018
DOMU_PASSTHROUGH_PATHS[0] = "/bus@f1000000/sdhci@f1050000"
DOMU_VCPUS[1] = 2
DOMU_MEM[1] = 1024

This is provided as the input configuration file for the imagebuilder.

Signed-off-by: Bruce Ashfield <bruce.ashfield@xilinx.com>
Signed-off-by: Ayan Kumar Halder <ayankuma@xilinx.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>
[stefano: minor style and grammar fixes]
Signed-off-by: Stefano Stabellini <stefano.stabellini@xilinx.com>

1 files changed, 82 insertions, 0 deletions

diff --git a/README_system_device_tree.md b/README_system_device_tree.md
new file mode 100644
index 0000000..5da8f06
--- /dev/null
+++ b/README_system_device_tree.md
@@ -0,0 +1,82 @@
+# ImageBuilder with System Device Tree
+
+Please refer to README.md to know more about ImageBuilder
+
+ImageBuilder can be used with System Device Tree to generate the
+scripts, binaries, etc required to boot Xen, Dom0 and DomU kernels on
+a hardware platform.
+The System Device Tree contains the hardware information as well as
+domain information.
+Refer https://gitenterprise.xilinx.com/stefanos/system-device-tree/blob/master/system-device-tree.dts
+for the system device tree example.
+
+## scripts/lop-xen.dts
+
+ImageBuilder derives its configuration from "domains" node in System
+Device Tree, e.g.:
+
+xen: domain@2 {
+    compatible = "openamp,domain-v1","openamp,hypervisor-v1";
+    cpus = <&cpus_a72 0x3 0x00000002>;
+    memory = <0x0 0x500000 0x0 0x7fb00000>;
+
+    dom0: domain@3 {
+        compatible = "openamp,domain-v1","xen,domain-v2";
+        cpus = <&cpus_a72 0x3 0x00000001>;
+        memory = <0x0 0x501000 0x0 0x3faff000>;
+    };
+
+    linux1: domain@4 {
+        compatible = "openamp,domain-v1","xen,domain-v2";
+        cpus = <&cpus_a72 0x3 0x00000001>;
+        memory = <0x0 0x501000 0x0 0x3faff000>;
+        access = <&mmc0 0x0>;
+    };
+
+    linux2: domain@5 {
+        compatible = "openamp,domain-v1","xen,domain-v2";
+        cpus = <&cpus_a72 0x3 0x00000001>;
+        memory = <0x0 0x40000000 0x0 0x40000000>;
+
+        firewallconfig = <&linux1 1 0>;
+    };
+};
+
+From the above snippet, ImageBuilder can deduce the number of domUs,
+count of virtual CPUs for Dom0, amount of memory for Dom0, count of
+virtual CPUs for each DomU, amount of memory for each DomU and device
+assigned to each  DomU.
+
+lop-xen.dts is the lopper dts file to generate the ImageBuilder config
+file (containing the above information) from System Device Tree.
+
+To use it, one needs to checkout the following two repositories:
+
+```
+git clone git://github.com/devicetree-org/lopper
+git clone https://gitenterprise.xilinx.com/stefanos/system-device-tree.git
+```
+
+Note: One needs to add a 'dom0' label (as shown in the previous snippet)
+for the node which represents dom0.
+
+And then run the following command from the "lopper" directory:
+
+```
+python3 lopper.py  -f --enhanced -i <path_to>/imagebuilder/scripts/lop-xen.dts \
+        <path_to>/system-device-tree/system-device-tree-xen.dts > config
+```
+
+For the dts snippet shown before, the following 'config' file will be
+generated:
+
+NUM_DOMUS=2
+DOM0_VCPUS = 2
+DOM0_MEM = 1018
+DOMU_VCPUS[0] = 2
+DOMU_MEM[0] = 1018
+DOMU_PASSTHROUGH_PATHS[0] = "/bus@f1000000/sdhci@f1050000"
+DOMU_VCPUS[1] = 2
+DOMU_MEM[1] = 1024
+
+Refer to README.md for a description of each of these options.