[PATCH v2 07/17] xen/arm: introduce a helper to parse device tree processor node

[Wei Chen <wei.chen@xxxxxxx>]

Processor NUMA ID information is stored in device tree's processor
node as "numa-node-id". We need a new helper to parse this ID from
processor node. If we get this ID from processor node, this ID's
validity still need to be checked. Once we got a invalid NUMA ID
from any processor node, the device tree will be marked as NUMA
information invalid.

Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
---
v1 -> v2:
1. Move numa_disabled from fdt_numa_processor_affinity_init
   to fdt_parse_numa_cpu_node.
2. Move invalid NUMA id check to fdt_parse_numa_cpu_node.
3. Return ENODATA for normal dtb without NUMA info.
4. Use NUMA status helpers instead of SRAT functions.
---
 xen/arch/arm/Makefile           |  1 +
 xen/arch/arm/include/asm/numa.h |  2 ++
 xen/arch/arm/numa.c             |  2 +-
 xen/arch/arm/numa_device_tree.c | 64 +++++++++++++++++++++++++++++++++
 4 files changed, 68 insertions(+), 1 deletion(-)
 create mode 100644 xen/arch/arm/numa_device_tree.c

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 9073398d6e..bbc68e3735 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -39,6 +39,7 @@ obj-y += mem_access.o
 obj-y += mm.o
 obj-y += monitor.o
 obj-$(CONFIG_NUMA) += numa.o
+obj-$(CONFIG_DEVICE_TREE_NUMA) += numa_device_tree.o
 obj-y += p2m.o
 obj-y += percpu.o
 obj-y += platform.o
diff --git a/xen/arch/arm/include/asm/numa.h b/xen/arch/arm/include/asm/numa.h
index e0c909cbb7..923ffbfd42 100644
--- a/xen/arch/arm/include/asm/numa.h
+++ b/xen/arch/arm/include/asm/numa.h
@@ -28,6 +28,8 @@ enum dt_numa_status {
     DT_NUMA_OFF,
 };
 
+extern enum dt_numa_status device_tree_numa;
+
 /*
  * In ACPI spec, 0-9 are the reserved values for node distance,
  * 10 indicates local node distance, 20 indicates remote node
diff --git a/xen/arch/arm/numa.c b/xen/arch/arm/numa.c
index 4dd7cf10ba..3e02cec646 100644
--- a/xen/arch/arm/numa.c
+++ b/xen/arch/arm/numa.c
@@ -20,7 +20,7 @@
 #include <xen/init.h>
 #include <xen/numa.h>
 
-static enum dt_numa_status __read_mostly device_tree_numa;
+enum dt_numa_status __read_mostly device_tree_numa;
 
 static unsigned char __read_mostly
 node_distance_map[MAX_NUMNODES][MAX_NUMNODES] = {
diff --git a/xen/arch/arm/numa_device_tree.c b/xen/arch/arm/numa_device_tree.c
new file mode 100644
index 0000000000..c031053d24
--- /dev/null
+++ b/xen/arch/arm/numa_device_tree.c
@@ -0,0 +1,64 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Arm Architecture support layer for device tree NUMA.
+ *
+ * Copyright (C) 2022 Arm Ltd
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#include <xen/init.h>
+#include <xen/nodemask.h>
+#include <xen/numa.h>
+#include <xen/libfdt/libfdt.h>
+#include <xen/device_tree.h>
+
+/* Callback for device tree processor affinity */
+static int __init fdt_numa_processor_affinity_init(nodeid_t node)
+{
+    numa_set_processor_nodes_parsed(node);
+    device_tree_numa = DT_NUMA_ON;
+
+    printk(KERN_INFO "DT: NUMA node %"PRIu8" processor parsed\n", node);
+
+    return 0;
+}
+
+/* Parse CPU NUMA node info */
+static int __init fdt_parse_numa_cpu_node(const void *fdt, int node)
+{
+    unsigned int nid;
+
+    if ( numa_disabled() )
+        return -EINVAL;
+
+    /*
+     * device_tree_get_u32 will return NUMA_NO_NODE when this CPU
+     * DT node doesn't have numa-node-id. This can help us to
+     * distinguish a bad DTB and a normal DTB without NUMA info.
+     */
+    nid = device_tree_get_u32(fdt, node, "numa-node-id", NUMA_NO_NODE);
+    if ( nid == NUMA_NO_NODE )
+    {
+        numa_fw_bad();
+        return -ENODATA;
+    }
+    else if ( nid >= MAX_NUMNODES )
+    {
+        printk(XENLOG_ERR "DT: CPU numa node id %u is invalid\n", nid);
+        numa_fw_bad();
+        return -EINVAL;
+    }
+
+    return fdt_numa_processor_affinity_init(nid);
+}
-- 
2.25.1