ACPICA: New: acpi_reset interface - write to reset register

Uses the FADT-defined reset register and reset value. Checks the
FADT flags for the reset register supported bit. Supports reset
register in memory or I/O space, but not in PCI config space
since the host has the information to do it.
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/hardware/hwxface.c

@@ -48,6 +48,43 @@
 #define _COMPONENT          ACPI_HARDWARE
 ACPI_MODULE_NAME("hwxface")
 
+/******************************************************************************
+ *
+ * FUNCTION:    acpi_reset
+ *
+ * PARAMETERS:  None
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Set reset register in memory or IO space. Note: Does not
+ *              support reset register in PCI config space, this must be
+ *              handled separately.
+ *
+ ******************************************************************************/
+acpi_status acpi_reset(void)
+{
+	struct acpi_generic_address *reset_reg;
+	acpi_status status;
+
+	ACPI_FUNCTION_TRACE(acpi_reset);
+
+	reset_reg = &acpi_gbl_FADT.reset_register;
+
+	/* Check if the reset register is supported */
+
+	if (!(acpi_gbl_FADT.flags & ACPI_FADT_RESET_REGISTER) ||
+	    !reset_reg->address) {
+		return_ACPI_STATUS(AE_NOT_EXIST);
+	}
+
+	/* Write the reset value to the reset register */
+
+	status = acpi_write(acpi_gbl_FADT.reset_value, reset_reg);
+	return_ACPI_STATUS(status);
+}
+
+ACPI_EXPORT_SYMBOL(acpi_reset)
+
 /******************************************************************************
  *
  * FUNCTION:    acpi_read

include/acpi/acpixf.h

@@ -322,6 +322,8 @@ acpi_resource_to_address64(struct acpi_resource *resource,
 /*
  * Hardware (ACPI device) interfaces
  */
+acpi_status acpi_reset(void);
+
 acpi_status acpi_get_register(u32 register_id, u32 * return_value);
 
 acpi_status acpi_get_register_unlocked(u32 register_id, u32 *return_value);