ACPICA: Revert "Revert "Enable multi-byte EC transfers

This reverts commit f23b9c7(http://git.moblin.org/cgit.cgi/acpica/commit/?id=f23b9c7)
The problem with this change was determined to be a problem with
the FreeBSD host OSL (OS services layer), not with this patch
itself. Therefore, re-introducing this change into the main ACPICA
code. See ACPICA bugzilla 863.

http://www.acpica.org/bugzilla/show_bug.cgi?id=863

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>
diff --git a/drivers/acpi/acpica/exprep.c b/drivers/acpi/acpica/exprep.c
index 98a331d..7aae29f 100644
--- a/drivers/acpi/acpica/exprep.c
+++ b/drivers/acpi/acpica/exprep.c
@@ -355,12 +355,10 @@
 		return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
 	}
 
-	/* Setup width (access granularity) fields */
+	/* Setup width (access granularity) fields (values are: 1, 2, 4, 8) */
 
 	obj_desc->common_field.access_byte_width = (u8)
-	    ACPI_DIV_8(access_bit_width);	/* 1,  2,  4,  8 */
-
-	obj_desc->common_field.access_bit_width = (u8) access_bit_width;
+	    ACPI_DIV_8(access_bit_width);
 
 	/*
 	 * base_byte_offset is the address of the start of the field within the
@@ -405,8 +403,9 @@
 {
 	union acpi_operand_object *obj_desc;
 	union acpi_operand_object *second_desc = NULL;
-	u32 type;
 	acpi_status status;
+	u32 access_byte_width;
+	u32 type;
 
 	ACPI_FUNCTION_TRACE(ex_prep_field_value);
 
@@ -421,8 +420,8 @@
 		type = acpi_ns_get_type(info->region_node);
 		if (type != ACPI_TYPE_REGION) {
 			ACPI_ERROR((AE_INFO,
-				    "Needed Region, found type 0x%X (%s)",
-				    type, acpi_ut_get_type_name(type)));
+				    "Needed Region, found type 0x%X (%s)", type,
+				    acpi_ut_get_type_name(type)));
 
 			return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
 		}
@@ -438,7 +437,8 @@
 	/* Initialize areas of the object that are common to all fields */
 
 	obj_desc->common_field.node = info->field_node;
-	status = acpi_ex_prep_common_field_object(obj_desc, info->field_flags,
+	status = acpi_ex_prep_common_field_object(obj_desc,
+						  info->field_flags,
 						  info->attribute,
 						  info->field_bit_position,
 						  info->field_bit_length);
@@ -455,27 +455,26 @@
 		obj_desc->field.region_obj =
 		    acpi_ns_get_attached_object(info->region_node);
 
+		/* Allow full data read from EC address space */
+
+		if ((obj_desc->field.region_obj->region.space_id ==
+		     ACPI_ADR_SPACE_EC)
+		    && (obj_desc->common_field.bit_length > 8)) {
+			access_byte_width =
+			    ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.
+							bit_length);
+
+			/* Maximum byte width supported is 255 */
+
+			if (access_byte_width < 256) {
+				obj_desc->common_field.access_byte_width =
+				    (u8)access_byte_width;
+			}
+		}
 		/* An additional reference for the container */
 
 		acpi_ut_add_reference(obj_desc->field.region_obj);
 
-		/* allow full data read from EC address space */
-		if (obj_desc->field.region_obj->region.space_id ==
-			ACPI_ADR_SPACE_EC) {
-			if (obj_desc->common_field.bit_length > 8) {
-				unsigned width =
-					ACPI_ROUND_BITS_UP_TO_BYTES(
-					obj_desc->common_field.bit_length);
-				// access_bit_width is u8, don't overflow it
-				if (width > 8)
-					width = 8;
-				obj_desc->common_field.access_byte_width =
-							width;
-				obj_desc->common_field.access_bit_width =
-							8 * width;
-			}
-		}
-
 		ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
 				  "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",
 				  obj_desc->field.start_field_bit_offset,