[PATCH] acpi: fadt: X_GPE0/1_BLK can be zero when not used

[Alex Hung]

ACPI spec states "if this register block is not supported, this field
contains zero".

This patch also replaces spaces by a tab for fwts_acpi_gas struct.

Signed-off-by: Alex Hung <alex.hung at canonical.com>
---
 src/acpi/fadt/fadt.c        | 33 +++++++++++++++++++++++----------
 src/lib/include/fwts_acpi.h |  6 +++---
 2 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/src/acpi/fadt/fadt.c b/src/acpi/fadt/fadt.c
index ab5a3b2b..3886b0ed 100644
--- a/src/acpi/fadt/fadt.c
+++ b/src/acpi/fadt/fadt.c
@@ -1519,6 +1519,17 @@ static void acpi_table_check_fadt_p_lvl3_lat(fwts_framework *fw, uint64_t pblk)
 	return;
 }
 
+static bool gas_nonzero(fwts_acpi_gas x_gpe0_blk) {
+	char *byte = (char*) &x_gpe0_blk;
+	uint8_t i;
+
+	for (i = 0; i < sizeof(fwts_acpi_gas); i++)
+		if (*byte++)
+			return true;
+
+	return false;
+}
+
 static void acpi_table_check_fadt_x_gpex_blk(fwts_framework *fw) {
 
 	if (fwts_acpi_is_reduced_hardware(fw))
@@ -1527,21 +1538,23 @@ static void acpi_table_check_fadt_x_gpex_blk(fwts_framework *fw) {
 	if (fadt->x_gpe0_blk.access_width == 1)
 		fwts_passed(fw, "FADT X_GPE0_BLK has correct byte access width.");
 	else {
-		fwts_failed(fw, LOG_LEVEL_HIGH,
-			"X_GPE0_BLKBadAccessWidth",
-			"FADT X_GPE0_BLK Access width 0x%2.2" PRIx8
-			" but it should be 1 (byte access).",
-			fadt->x_gpe0_blk.access_width);
+		if (gas_nonzero(fadt->x_gpe0_blk))
+			fwts_failed(fw, LOG_LEVEL_HIGH,
+				"X_GPE0_BLKBadAccessWidth",
+				"FADT X_GPE0_BLK Access width 0x%2.2" PRIx8
+				" but it should be 1 (byte access).",
+				fadt->x_gpe0_blk.access_width);
 	}
 
 	if (fadt->x_gpe1_blk.access_width == 1)
 		fwts_passed(fw, "FADT X_GPE1_BLK has correct byte access width.");
 	else {
-		fwts_failed(fw, LOG_LEVEL_HIGH,
-			"X_GPE1_BLKBadAccessWidth",
-			"FADT X_GPE1_BLK Access width 0x%2.2" PRIx8
-			" but it should be 1 (byte access).",
-			fadt->x_gpe1_blk.access_width);
+		if (gas_nonzero(fadt->x_gpe1_blk))
+			fwts_failed(fw, LOG_LEVEL_HIGH,
+				"X_GPE1_BLKBadAccessWidth",
+				"FADT X_GPE1_BLK Access width 0x%2.2" PRIx8
+				" but it should be 1 (byte access).",
+				fadt->x_gpe1_blk.access_width);
 	}
 }
 
diff --git a/src/lib/include/fwts_acpi.h b/src/lib/include/fwts_acpi.h
index efa988f2..89fb128c 100644
--- a/src/lib/include/fwts_acpi.h
+++ b/src/lib/include/fwts_acpi.h
@@ -117,9 +117,9 @@ extern const char *fwts_acpi_fadt_preferred_pm_profile[];
 typedef struct {
 	uint8_t 	address_space_id;
 	uint8_t		register_bit_width;
-        uint8_t 	register_bit_offset;
-        uint8_t 	access_width;
-        uint64_t 	address;
+	uint8_t 	register_bit_offset;
+	uint8_t 	access_width;
+	uint64_t 	address;
 } __attribute__ ((packed)) fwts_acpi_gas;
 
 /*
-- 
2.25.1