[PATCH] ARM: ACPI: Fix the helper which checks if only a /chosen node

[Shannon Zhao]

From: Shannon Zhao <shannon.zhao at linaro.org>

Assuming that there are several other nodes and a /chosen node in a DTS
and the /chosen node is last node, of_scan_flat_dt() will return 0 while
we expect it returns 1 when it's used to call a function to check if
there is only a /chosen node in DTS.

Fix this by passing a meaningful parameter instead of NULL to
of_scan_flat_dt() to record if it finds a node that is not /chosen node.

Signed-off-by: Shannon Zhao <shannon.zhao at linaro.org>
---
 arch/arm64/kernel/acpi.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index 19de753..51c988c 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -60,12 +60,15 @@ static int __init dt_scan_depth1_nodes(unsigned long node,
 				       const char *uname, int depth,
 				       void *data)
 {
+	bool *found = data;
+
 	/*
 	 * Return 1 as soon as we encounter a node at depth 1 that is
 	 * not the /chosen node.
 	 */
 	if (depth == 1 && (strcmp(uname, "chosen") != 0))
-		return 1;
+		*found = true;
+
 	return 0;
 }
 
@@ -176,15 +179,20 @@ out:
  */
 void __init acpi_boot_table_init(void)
 {
+	bool found = false;
 	/*
 	 * 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)
 	 */
-	if (param_acpi_off ||
-	    (!param_acpi_force && of_scan_flat_dt(dt_scan_depth1_nodes, NULL)))
+	if (param_acpi_off) {
 		return;
+	} else if (!param_acpi_force) {
+		of_scan_flat_dt(dt_scan_depth1_nodes, &found);
+		if (found)
+			return;
+	}
 
 	/*
 	 * ACPI is disabled at this point. Enable it in order to parse
-- 
2.0.4