src: Never overwrite `fadt->flags`

Instead, just flip the desired bits using bitwise operations. As this is
initially zero, the resulting value is the same. This allows flags to be
set from anywhere regardless of execution order.

Tested on Asus P8Z77-V LX2 with Linux 5.7.6 and Windows 10 at the end of
the patch train, both operating systems are able to boot successfully.

Change-Id: Icfd580a20524936cd0adac574331b09fb2aea925
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43387
Reviewed-by: Nico Huber <nico.h@gmx.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

8 files changed, 15 insertions, 15 deletions

diff --git a/src/southbridge/intel/bd82x6x/fadt.c b/src/southbridge/intel/bd82x6x/fadt.c
index 40cddb953e..7b36583495 100644
--- a/src/southbridge/intel/bd82x6x/fadt.c
+++ b/src/southbridge/intel/bd82x6x/fadt.c
@@ -50,7 +50,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x00;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_DEVICES | ACPI_FADT_8042;
 
-	fadt->flags = ACPI_FADT_WBINVD |
+	fadt->flags |= ACPI_FADT_WBINVD |
 			ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_SLEEP_BUTTON |
 			ACPI_FADT_RESET_REGISTER |
diff --git a/src/southbridge/intel/i82371eb/fadt.c b/src/southbridge/intel/i82371eb/fadt.c
index 5a3326bc8f..c775af0c92 100644
--- a/src/southbridge/intel/i82371eb/fadt.c
+++ b/src/southbridge/intel/i82371eb/fadt.c
@@ -103,7 +103,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	 * 18   FORCE_APIC_CLUSTER_MODEL
 	 * 19   FORCE_APIC_PHYSICAL_DESTINATION_MODE
 	 */
-	fadt->flags = 0xa5 | ACPI_FADT_RESET_REGISTER;
+	fadt->flags |= 0xa5 | ACPI_FADT_RESET_REGISTER;
 
 	fadt->reset_reg.space_id = ACPI_ADDRESS_SPACE_IO;
 	fadt->reset_reg.bit_width = 8;
diff --git a/src/southbridge/intel/i82801dx/fadt.c b/src/southbridge/intel/i82801dx/fadt.c
index 319e6a6f88..8be39bfdb6 100644
--- a/src/southbridge/intel/i82801dx/fadt.c
+++ b/src/southbridge/intel/i82801dx/fadt.c
@@ -50,7 +50,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x00;
 	fadt->iapc_boot_arch = 0x03;
 
-	fadt->flags = ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
+	fadt->flags |= ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_C2_MP_SUPPORTED | ACPI_FADT_SLEEP_BUTTON |
 			ACPI_FADT_S4_RTC_WAKE | ACPI_FADT_RESET_REGISTER |
 			ACPI_FADT_PLATFORM_CLOCK;
diff --git a/src/southbridge/intel/i82801gx/fadt.c b/src/southbridge/intel/i82801gx/fadt.c
index 200e7e51b9..35a1facb55 100644
--- a/src/southbridge/intel/i82801gx/fadt.c
+++ b/src/southbridge/intel/i82801gx/fadt.c
@@ -49,7 +49,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->mon_alrm = 0x00;
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_8042 | ACPI_FADT_LEGACY_DEVICES;
-	fadt->flags = (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
+	fadt->flags |= (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
 		       | ACPI_FADT_SLEEP_BUTTON | ACPI_FADT_S4_RTC_WAKE
 		       | ACPI_FADT_PLATFORM_CLOCK | ACPI_FADT_RESET_REGISTER
 		       | ACPI_FADT_C2_MP_SUPPORTED);
diff --git a/src/southbridge/intel/i82801ix/fadt.c b/src/southbridge/intel/i82801ix/fadt.c
index 1fd8f73e3b..710f585f8c 100644
--- a/src/southbridge/intel/i82801ix/fadt.c
+++ b/src/southbridge/intel/i82801ix/fadt.c
@@ -42,7 +42,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->mon_alrm = 0x00;
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_FREE;
-	fadt->flags = ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
+	fadt->flags |= ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_SLEEP_BUTTON | ACPI_FADT_S4_RTC_WAKE |
 			ACPI_FADT_DOCKING_SUPPORTED | ACPI_FADT_RESET_REGISTER |
 			ACPI_FADT_PLATFORM_CLOCK;
diff --git a/src/southbridge/intel/i82801jx/fadt.c b/src/southbridge/intel/i82801jx/fadt.c
index 45003f0698..6f80aa6d66 100644
--- a/src/southbridge/intel/i82801jx/fadt.c
+++ b/src/southbridge/intel/i82801jx/fadt.c
@@ -45,7 +45,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->mon_alrm = 0x00;
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_8042 | ACPI_FADT_LEGACY_DEVICES;
-	fadt->flags = (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
+	fadt->flags |= (ACPI_FADT_WBINVD | ACPI_FADT_C1_SUPPORTED
 		       | ACPI_FADT_SLEEP_BUTTON | ACPI_FADT_S4_RTC_WAKE
 		       | ACPI_FADT_PLATFORM_CLOCK | ACPI_FADT_RESET_REGISTER
 		       | ACPI_FADT_C2_MP_SUPPORTED);
diff --git a/src/southbridge/intel/ibexpeak/fadt.c b/src/southbridge/intel/ibexpeak/fadt.c
index a4fed96880..103fda6ca9 100644
--- a/src/southbridge/intel/ibexpeak/fadt.c
+++ b/src/southbridge/intel/ibexpeak/fadt.c
@@ -50,7 +50,7 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x32;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_DEVICES | ACPI_FADT_8042;
 
-	fadt->flags = ACPI_FADT_WBINVD |
+	fadt->flags |= ACPI_FADT_WBINVD |
 			ACPI_FADT_C1_SUPPORTED |
 			ACPI_FADT_SLEEP_BUTTON |
 			ACPI_FADT_RESET_REGISTER |
diff --git a/src/southbridge/intel/lynxpoint/fadt.c b/src/southbridge/intel/lynxpoint/fadt.c
index 05189de60c..7c1bef9941 100644
--- a/src/southbridge/intel/lynxpoint/fadt.c
+++ b/src/southbridge/intel/lynxpoint/fadt.c
@@ -55,14 +55,14 @@ void acpi_fill_fadt(acpi_fadt_t *fadt)
 	fadt->century = 0x00;
 	fadt->iapc_boot_arch = ACPI_FADT_LEGACY_DEVICES | ACPI_FADT_8042;
 
-	fadt->flags = ACPI_FADT_WBINVD |
-		      ACPI_FADT_C1_SUPPORTED |
-		      ACPI_FADT_C2_MP_SUPPORTED |
-		      ACPI_FADT_SLEEP_BUTTON |
-		      ACPI_FADT_RESET_REGISTER |
-		      ACPI_FADT_SEALED_CASE |
-		      ACPI_FADT_S4_RTC_WAKE |
-		      ACPI_FADT_PLATFORM_CLOCK;
+	fadt->flags |= ACPI_FADT_WBINVD |
+		       ACPI_FADT_C1_SUPPORTED |
+		       ACPI_FADT_C2_MP_SUPPORTED |
+		       ACPI_FADT_SLEEP_BUTTON |
+		       ACPI_FADT_RESET_REGISTER |
+		       ACPI_FADT_SEALED_CASE |
+		       ACPI_FADT_S4_RTC_WAKE |
+		       ACPI_FADT_PLATFORM_CLOCK;
 
 	if (cfg->docking_supported)
 		fadt->flags |= ACPI_FADT_DOCKING_SUPPORTED;