Hardware: Add optimized access bit width support

For Access Size = 0, it actually can use user expected access bit width.
This patch implements this. Lv Zheng.

Signed-off-by: Lv Zheng <lv.zheng@intel.com>

source/components/hardware/hwregs.c

@@ -126,6 +126,11 @@
 
 /* Local Prototypes */
 
+static UINT8
+AcpiHwGetAccessBitWidth (
+    ACPI_GENERIC_ADDRESS    *Reg,
+    UINT8                   MaxBitWidth);
+
 static ACPI_STATUS
 AcpiHwReadMultiple (
     UINT32                  *Value,
@@ -141,6 +146,43 @@ AcpiHwWriteMultiple (
 #endif /* !ACPI_REDUCED_HARDWARE */
 
 
+/******************************************************************************
+ *
+ * FUNCTION:    AcpiHwGetAccessBitWidth
+ *
+ * PARAMETERS:  Reg                 - GAS register structure
+ *              MaxBitWidth         - Max BitWidth supported (32 or 64)
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Obtain optimal access bit width
+ *
+ ******************************************************************************/
+
+static UINT8
+AcpiHwGetAccessBitWidth (
+    ACPI_GENERIC_ADDRESS    *Reg,
+    UINT8                   MaxBitWidth)
+{
+
+    if (!Reg->AccessWidth)
+    {
+        if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_IO)
+        {
+            return (32);
+        }
+        else
+        {
+            return (MaxBitWidth);
+        }
+    }
+    else
+    {
+        return (1 << (Reg->AccessWidth + 2));
+    }
+}
+
+
 /******************************************************************************
  *
  * FUNCTION:    AcpiHwValidateRegister
@@ -206,8 +248,7 @@ AcpiHwValidateRegister (
 
     /* Validate the BitWidth, convert AccessWidth into number of bits */
 
-    AccessWidth = Reg->AccessWidth ? Reg->AccessWidth : 1;
-    AccessWidth = 1 << (AccessWidth + 2);
+    AccessWidth = AcpiHwGetAccessBitWidth (Reg, MaxBitWidth);
     BitWidth = ACPI_ROUND_UP (Reg->BitOffset + Reg->BitWidth, AccessWidth);
     if (MaxBitWidth < BitWidth)
     {
@@ -270,8 +311,7 @@ AcpiHwRead (
      * into number of bits based
      */
     *Value = 0;
-    AccessWidth = Reg->AccessWidth ? Reg->AccessWidth : 1;
-    AccessWidth = 1 << (AccessWidth + 2);
+    AccessWidth = AcpiHwGetAccessBitWidth (Reg, 32);
     BitWidth = Reg->BitOffset + Reg->BitWidth;
     BitOffset = Reg->BitOffset;
 
@@ -373,8 +413,7 @@ AcpiHwWrite (
 
     /* Convert AccessWidth into number of bits based */
 
-    AccessWidth = Reg->AccessWidth ? Reg->AccessWidth : 1;
-    AccessWidth = 1 << (AccessWidth + 2);
+    AccessWidth = AcpiHwGetAccessBitWidth (Reg, 32);
     BitWidth = Reg->BitOffset + Reg->BitWidth;
     BitOffset = Reg->BitOffset;