[DEBUG 14/21] powerpc/mm: Create numa nodes for hotplug memory

[Anshuman Khandual]

From: Reza Arbab <ar...@linux.vnet.ibm.com>

When scanning the device tree to initialize the system NUMA topology,
process dt elements with compatible id "ibm,hotplug-aperture" to create
memoryless numa nodes.

These nodes will be filled when hotplug occurs within the associated
address range.

Signed-off-by: Reza Arbab <ar...@linux.vnet.ibm.com>
Signed-off-by: Anshuman Khandual <khand...@linux.vnet.ibm.com>
---
 .../bindings/powerpc/opal/hotplug-aperture.txt     | 26 ++++++++++++++++++++++
 arch/powerpc/mm/numa.c                             | 10 +++++++--
 2 files changed, 34 insertions(+), 2 deletions(-)
 create mode 100644 
Documentation/devicetree/bindings/powerpc/opal/hotplug-aperture.txt

diff --git 
a/Documentation/devicetree/bindings/powerpc/opal/hotplug-aperture.txt 
b/Documentation/devicetree/bindings/powerpc/opal/hotplug-aperture.txt
new file mode 100644
index 0000000..b8dffaa
--- /dev/null
+++ b/Documentation/devicetree/bindings/powerpc/opal/hotplug-aperture.txt
@@ -0,0 +1,26 @@
+Designated hotplug memory
+-------------------------
+
+This binding describes a region of hotplug memory which is not present at boot,
+allowing its eventual NUMA associativity to be prespecified.
+
+Required properties:
+
+- compatible
+       "ibm,hotplug-aperture"
+
+- reg
+       base address and size of the region (standard definition)
+
+- ibm,associativity
+       NUMA associativity (standard definition)
+
+Example:
+
+A 2 GiB aperture at 0x100000000, to be part of nid 3 when hotplugged:
+
+       hotplug-memory@100000000 {
+               compatible = "ibm,hotplug-aperture";
+               reg = <0x0 0x100000000 0x0 0x80000000>;
+               ibm,associativity = <0x4 0x0 0x0 0x0 0x3>;
+       };
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 6def078..5370833 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -717,6 +717,12 @@ static void __init parse_drconf_memory(struct device_node 
*memory)
        }
 }
 
+static const struct of_device_id memory_match[] = {
+       { .type = "memory" },
+       { .compatible = "ibm,hotplug-aperture" },
+       { /* sentinel */ }
+};
+
 static int __init parse_numa_properties(void)
 {
        struct device_node *memory;
@@ -761,7 +767,7 @@ static int __init parse_numa_properties(void)
 
        get_n_mem_cells(&n_mem_addr_cells, &n_mem_size_cells);
 
-       for_each_node_by_type(memory, "memory") {
+       for_each_matching_node(memory, memory_match) {
                unsigned long start;
                unsigned long size;
                int nid;
@@ -1056,7 +1062,7 @@ static int hot_add_node_scn_to_nid(unsigned long scn_addr)
        struct device_node *memory;
        int nid = -1;
 
-       for_each_node_by_type(memory, "memory") {
+       for_each_matching_node(memory, memory_match) {
                unsigned long start, size;
                int ranges;
                const __be32 *memcell_buf;
-- 
2.9.3