ACPICA: Preserve all PM control reserved and ignored bits

As per the ACPI specification, preserve (read/modify/write) all
bits that are defined as either reserved or ignored (PM control
control registers only.)
Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

drivers/acpi/acpica/aclocal.h

@@ -780,7 +780,15 @@ struct acpi_bit_register_info {
  * must be preserved.
  */
 #define ACPI_PM1_STATUS_PRESERVED_BITS          0x0800	/* Bit 11 */
-#define ACPI_PM1_CONTROL_PRESERVED_BITS         0x0200	/* Bit 9 (whatever) */
+
+/* For control registers, both ignored and reserved bits must be preserved */
+
+#define ACPI_PM1_CONTROL_IGNORED_BITS           0x0201	/* Bits 9, 0(SCI_EN) */
+#define ACPI_PM1_CONTROL_RESERVED_BITS          0xC1F8	/* Bits 14-15, 3-8 */
+#define ACPI_PM1_CONTROL_PRESERVED_BITS \
+	       (ACPI_PM1_CONTROL_IGNORED_BITS | ACPI_PM1_CONTROL_RESERVED_BITS)
+
+#define ACPI_PM2_CONTROL_PRESERVED_BITS         0xFFFFFFFE	/* All except bit 0 */
 
 /*
  * Register IDs

drivers/acpi/acpica/hwregs.c

@@ -328,6 +328,21 @@ acpi_status acpi_hw_register_write(u32 register_id, u32 value)
 
 	case ACPI_REGISTER_PM2_CONTROL:	/* 8-bit access */
 
+		/*
+		 * For control registers, all reserved bits must be preserved,
+		 * as per the ACPI spec.
+		 */
+		status =
+		    acpi_read(&read_value, &acpi_gbl_FADT.xpm2_control_block);
+		if (ACPI_FAILURE(status)) {
+			goto exit;
+		}
+
+		/* Insert the bits to be preserved */
+
+		ACPI_INSERT_BITS(value, ACPI_PM2_CONTROL_PRESERVED_BITS,
+				 read_value);
+
 		status = acpi_write(value, &acpi_gbl_FADT.xpm2_control_block);
 		break;