v4.19.13 snapshot.
diff --git a/drivers/acpi/acpica/hwacpi.c b/drivers/acpi/acpica/hwacpi.c
new file mode 100644
index 0000000..525e6ea
--- /dev/null
+++ b/drivers/acpi/acpica/hwacpi.c
@@ -0,0 +1,147 @@
+// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
+/******************************************************************************
+ *
+ * Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
+ *
+ * Copyright (C) 2000 - 2018, Intel Corp.
+ *
+ *****************************************************************************/
+
+#include <acpi/acpi.h>
+#include "accommon.h"
+
+#define _COMPONENT ACPI_HARDWARE
+ACPI_MODULE_NAME("hwacpi")
+
+#if (!ACPI_REDUCED_HARDWARE) /* Entire module */
+/******************************************************************************
+ *
+ * FUNCTION: acpi_hw_set_mode
+ *
+ * PARAMETERS: mode - SYS_MODE_ACPI or SYS_MODE_LEGACY
+ *
+ * RETURN: Status
+ *
+ * DESCRIPTION: Transitions the system into the requested mode.
+ *
+ ******************************************************************************/
+acpi_status acpi_hw_set_mode(u32 mode)
+{
+
+ acpi_status status;
+
+ ACPI_FUNCTION_TRACE(hw_set_mode);
+
+ /* If the Hardware Reduced flag is set, machine is always in acpi mode */
+
+ if (acpi_gbl_reduced_hardware) {
+ return_ACPI_STATUS(AE_OK);
+ }
+
+ /*
+ * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
+ * system does not support mode transition.
+ */
+ if (!acpi_gbl_FADT.smi_command) {
+ ACPI_ERROR((AE_INFO,
+ "No SMI_CMD in FADT, mode transition failed"));
+ return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
+ }
+
+ /*
+ * ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
+ * in FADT: If it is zero, enabling or disabling is not supported.
+ * As old systems may have used zero for mode transition,
+ * we make sure both the numbers are zero to determine these
+ * transitions are not supported.
+ */
+ if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
+ ACPI_ERROR((AE_INFO,
+ "No ACPI mode transition supported in this system "
+ "(enable/disable both zero)"));
+ return_ACPI_STATUS(AE_OK);
+ }
+
+ switch (mode) {
+ case ACPI_SYS_MODE_ACPI:
+
+ /* BIOS should have disabled ALL fixed and GP events */
+
+ status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
+ (u32) acpi_gbl_FADT.acpi_enable, 8);
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+ "Attempting to enable ACPI mode\n"));
+ break;
+
+ case ACPI_SYS_MODE_LEGACY:
+ /*
+ * BIOS should clear all fixed status bits and restore fixed event
+ * enable bits to default
+ */
+ status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
+ (u32)acpi_gbl_FADT.acpi_disable, 8);
+ ACPI_DEBUG_PRINT((ACPI_DB_INFO,
+ "Attempting to enable Legacy (non-ACPI) mode\n"));
+ break;
+
+ default:
+
+ return_ACPI_STATUS(AE_BAD_PARAMETER);
+ }
+
+ if (ACPI_FAILURE(status)) {
+ ACPI_EXCEPTION((AE_INFO, status,
+ "Could not write ACPI mode change"));
+ return_ACPI_STATUS(status);
+ }
+
+ return_ACPI_STATUS(AE_OK);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION: acpi_hw_get_mode
+ *
+ * PARAMETERS: none
+ *
+ * RETURN: SYS_MODE_ACPI or SYS_MODE_LEGACY
+ *
+ * DESCRIPTION: Return current operating state of system. Determined by
+ * querying the SCI_EN bit.
+ *
+ ******************************************************************************/
+
+u32 acpi_hw_get_mode(void)
+{
+ acpi_status status;
+ u32 value;
+
+ ACPI_FUNCTION_TRACE(hw_get_mode);
+
+ /* If the Hardware Reduced flag is set, machine is always in acpi mode */
+
+ if (acpi_gbl_reduced_hardware) {
+ return_UINT32(ACPI_SYS_MODE_ACPI);
+ }
+
+ /*
+ * ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
+ * system does not support mode transition.
+ */
+ if (!acpi_gbl_FADT.smi_command) {
+ return_UINT32(ACPI_SYS_MODE_ACPI);
+ }
+
+ status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);
+ if (ACPI_FAILURE(status)) {
+ return_UINT32(ACPI_SYS_MODE_LEGACY);
+ }
+
+ if (value) {
+ return_UINT32(ACPI_SYS_MODE_ACPI);
+ } else {
+ return_UINT32(ACPI_SYS_MODE_LEGACY);
+ }
+}
+
+#endif /* !ACPI_REDUCED_HARDWARE */