[PATCH 10/13] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI

[shannon.zhao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org]

From: Shannon Zhao <shannon.zhao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>

When it's a Xen domain0 booting with ACPI, it will supply a /chosen and
a /hypervisor node in DT. So check if it needs to enable ACPI.

Signed-off-by: Shannon Zhao <shannon.zhao-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 arch/arm64/kernel/acpi.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 19de753..7b67426 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -62,10 +62,13 @@ static int __init dt_scan_depth1_nodes(unsigned long node,
 {
 	/*
 	 * Return 1 as soon as we encounter a node at depth 1 that is
-	 * not the /chosen node.
+	 * not the /chosen node or to Xen initial domain that is not
+	 * either /chosen or /hypervisor node.
 	 */
 	if (depth == 1 && (strcmp(uname, "chosen") != 0))
-		return 1;
+		if (!xen_initial_domain() || (strcmp(uname, "hypervisor") != 0))
+			return 1;
+
 	return 0;
 }
 
@@ -179,8 +182,9 @@ void __init acpi_boot_table_init(void)
 	/*
 	 * Enable ACPI instead of device tree unless
 	 * - ACPI has been disabled explicitly (acpi=off), or
-	 * - the device tree is not empty (it has more than just a /chosen node)
-	 *   and ACPI has not been force enabled (acpi=force)
+	 * - the device tree is not empty (it has more than just a /chosen node
+	 *   or to Xen initial domain it has more than a /chosen node and
+	 *   /hypervisor node) and ACPI has not been force enabled (acpi=force)
 	 */
 	if (param_acpi_off ||
 	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
-- 
2.1.0