1 files changed, 197 insertions, 33 deletions
diff --git a/source/components/hardware/hwregs.c b/source/components/hardware/hwregs.c
index bc85c96b553f6..744186b87c1dd 100644
--- a/source/components/hardware/hwregs.c
+++ b/source/components/hardware/hwregs.c
@@ -54,6 +54,12 @@
 
 /* Local Prototypes */
 
+static UINT8
+AcpiHwGetAccessBitWidth (
+    UINT64                  Address,
+    ACPI_GENERIC_ADDRESS    *Reg,
+    UINT8                   MaxBitWidth);
+
 static ACPI_STATUS
 AcpiHwReadMultiple (
     UINT32                  *Value,
@@ -71,6 +77,90 @@ AcpiHwWriteMultiple (
 
 /******************************************************************************
  *
+ * FUNCTION:    AcpiHwGetAccessBitWidth
+ *
+ * PARAMETERS:  Address             - GAS register address
+ *              Reg                 - GAS register structure
+ *              MaxBitWidth         - Max BitWidth supported (32 or 64)
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Obtain optimal access bit width
+ *
+ ******************************************************************************/
+
+static UINT8
+AcpiHwGetAccessBitWidth (
+    UINT64                  Address,
+    ACPI_GENERIC_ADDRESS    *Reg,
+    UINT8                   MaxBitWidth)
+{
+    UINT8                   AccessBitWidth;
+
+
+    /*
+     * GAS format "register", used by FADT:
+     *  1. Detected if BitOffset is 0 and BitWidth is 8/16/32/64;
+     *  2. AccessSize field is ignored and BitWidth field is used for
+     *     determining the boundary of the IO accesses.
+     * GAS format "region", used by APEI registers:
+     *  1. Detected if BitOffset is not 0 or BitWidth is not 8/16/32/64;
+     *  2. AccessSize field is used for determining the boundary of the
+     *     IO accesses;
+     *  3. BitOffset/BitWidth fields are used to describe the "region".
+     *
+     * Note: This algorithm assumes that the "Address" fields should always
+     *       contain aligned values.
+     */
+    if (!Reg->BitOffset && Reg->BitWidth &&
+        ACPI_IS_POWER_OF_TWO (Reg->BitWidth) &&
+        ACPI_IS_ALIGNED (Reg->BitWidth, 8))
+    {
+        AccessBitWidth = Reg->BitWidth;
+    }
+    else if (Reg->AccessWidth)
+    {
+        AccessBitWidth = (1 << (Reg->AccessWidth + 2));
+    }
+    else
+    {
+        AccessBitWidth = ACPI_ROUND_UP_POWER_OF_TWO_8 (
+            Reg->BitOffset + Reg->BitWidth);
+        if (AccessBitWidth <= 8)
+        {
+            AccessBitWidth = 8;
+        }
+        else
+        {
+            while (!ACPI_IS_ALIGNED (Address, AccessBitWidth >> 3))
+            {
+                AccessBitWidth >>= 1;
+            }
+        }
+    }
+
+    /* Maximum IO port access bit width is 32 */
+
+    if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_IO)
+    {
+        MaxBitWidth = 32;
+    }
+
+    /*
+     * Return access width according to the requested maximum access bit width,
+     * as the caller should know the format of the register and may enforce
+     * a 32-bit accesses.
+     */
+    if (AccessBitWidth < MaxBitWidth)
+    {
+        return (AccessBitWidth);
+    }
+    return (MaxBitWidth);
+}
+
+
+/******************************************************************************
+ *
  * FUNCTION:    AcpiHwValidateRegister
  *
  * PARAMETERS:  Reg                 - GAS register structure
@@ -91,6 +181,9 @@ AcpiHwValidateRegister (
     UINT8                   MaxBitWidth,
     UINT64                  *Address)
 {
+    UINT8                   BitWidth;
+    UINT8                   AccessWidth;
+
 
     /* Must have a valid pointer to a GAS structure */
 
@@ -120,24 +213,25 @@ AcpiHwValidateRegister (
         return (AE_SUPPORT);
     }
 
-    /* Validate the BitWidth */
+    /* Validate the AccessWidth */
 
-    if ((Reg->BitWidth != 8) &&
-        (Reg->BitWidth != 16) &&
-        (Reg->BitWidth != 32) &&
-        (Reg->BitWidth != MaxBitWidth))
+    if (Reg->AccessWidth > 4)
     {
         ACPI_ERROR ((AE_INFO,
-            "Unsupported register bit width: 0x%X", Reg->BitWidth));
+            "Unsupported register access width: 0x%X", Reg->AccessWidth));
         return (AE_SUPPORT);
     }
 
-    /* Validate the BitOffset. Just a warning for now. */
+    /* Validate the BitWidth, convert AccessWidth into number of bits */
 
-    if (Reg->BitOffset != 0)
+    AccessWidth = AcpiHwGetAccessBitWidth (*Address, Reg, MaxBitWidth);
+    BitWidth = ACPI_ROUND_UP (Reg->BitOffset + Reg->BitWidth, AccessWidth);
+    if (MaxBitWidth < BitWidth)
     {
         ACPI_WARNING ((AE_INFO,
-            "Unsupported register bit offset: 0x%X", Reg->BitOffset));
+            "Requested bit width 0x%X is smaller than register bit width 0x%X",
+            MaxBitWidth, BitWidth));
+        return (AE_SUPPORT);
     }
 
     return (AE_OK);
@@ -158,10 +252,7 @@ AcpiHwValidateRegister (
  *              64-bit values is not needed.
  *
  * LIMITATIONS: <These limitations also apply to AcpiHwWrite>
- *      BitWidth must be exactly 8, 16, or 32.
  *      SpaceID must be SystemMemory or SystemIO.
- *      BitOffset and AccessWidth are currently ignored, as there has
- *          not been a need to implement these.
  *
  ******************************************************************************/
 
@@ -171,7 +262,12 @@ AcpiHwRead (
     ACPI_GENERIC_ADDRESS    *Reg)
 {
     UINT64                  Address;
+    UINT8                   AccessWidth;
+    UINT32                  BitWidth;
+    UINT8                   BitOffset;
     UINT64                  Value64;
+    UINT32                  Value32;
+    UINT8                   Index;
     ACPI_STATUS             Status;
 
 
@@ -186,30 +282,58 @@ AcpiHwRead (
         return (Status);
     }
 
-    /* Initialize entire 32-bit return value to zero */
-
+    /*
+     * Initialize entire 32-bit return value to zero, convert AccessWidth
+     * into number of bits based
+     */
     *Value = 0;
+    AccessWidth = AcpiHwGetAccessBitWidth (Address, Reg, 32);
+    BitWidth = Reg->BitOffset + Reg->BitWidth;
+    BitOffset = Reg->BitOffset;
 
     /*
      * Two address spaces supported: Memory or IO. PCI_Config is
      * not supported here because the GAS structure is insufficient
      */
-    if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+    Index = 0;
+    while (BitWidth)
     {
-        Status = AcpiOsReadMemory ((ACPI_PHYSICAL_ADDRESS)
-            Address, &Value64, Reg->BitWidth);
+        if (BitOffset >= AccessWidth)
+        {
+            Value32 = 0;
+            BitOffset -= AccessWidth;
+        }
+        else
+        {
+            if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+            {
+                Status = AcpiOsReadMemory ((ACPI_PHYSICAL_ADDRESS)
+                    Address + Index * ACPI_DIV_8 (AccessWidth),
+                    &Value64, AccessWidth);
+                Value32 = (UINT32) Value64;
+            }
+            else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+            {
+                Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
+                    Address + Index * ACPI_DIV_8 (AccessWidth),
+                    &Value32, AccessWidth);
+            }
+        }
 
-        *Value = (UINT32) Value64;
-    }
-    else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
-    {
-        Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
-            Address, Value, Reg->BitWidth);
+        /*
+         * Use offset style bit writes because "Index * AccessWidth" is
+         * ensured to be less than 32-bits by AcpiHwValidateRegister().
+         */
+        ACPI_SET_BITS (Value, Index * AccessWidth,
+            ACPI_MASK_BITS_ABOVE_32 (AccessWidth), Value32);
+
+        BitWidth -= BitWidth > AccessWidth ? AccessWidth : BitWidth;
+        Index++;
     }
 
     ACPI_DEBUG_PRINT ((ACPI_DB_IO,
         "Read:  %8.8X width %2d from %8.8X%8.8X (%s)\n",
-        *Value, Reg->BitWidth, ACPI_FORMAT_UINT64 (Address),
+        *Value, AccessWidth, ACPI_FORMAT_UINT64 (Address),
         AcpiUtGetRegionName (Reg->SpaceId)));
 
     return (Status);
@@ -237,6 +361,12 @@ AcpiHwWrite (
     ACPI_GENERIC_ADDRESS    *Reg)
 {
     UINT64                  Address;
+    UINT8                   AccessWidth;
+    UINT32                  BitWidth;
+    UINT8                   BitOffset;
+    UINT64                  Value64;
+    UINT32                  Value32;
+    UINT8                   Index;
     ACPI_STATUS             Status;
 
 
@@ -251,24 +381,58 @@ AcpiHwWrite (
         return (Status);
     }
 
+    /* Convert AccessWidth into number of bits based */
+
+    AccessWidth = AcpiHwGetAccessBitWidth (Address, Reg, 32);
+    BitWidth = Reg->BitOffset + Reg->BitWidth;
+    BitOffset = Reg->BitOffset;
+
     /*
      * Two address spaces supported: Memory or IO. PCI_Config is
      * not supported here because the GAS structure is insufficient
      */
-    if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+    Index = 0;
+    while (BitWidth)
     {
-        Status = AcpiOsWriteMemory ((ACPI_PHYSICAL_ADDRESS)
-            Address, (UINT64) Value, Reg->BitWidth);
-    }
-    else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
-    {
-        Status = AcpiHwWritePort ((ACPI_IO_ADDRESS)
-            Address, Value, Reg->BitWidth);
+        /*
+         * Use offset style bit reads because "Index * AccessWidth" is
+         * ensured to be less than 32-bits by AcpiHwValidateRegister().
+         */
+        Value32 = ACPI_GET_BITS (&Value, Index * AccessWidth,
+            ACPI_MASK_BITS_ABOVE_32 (AccessWidth));
+
+        if (BitOffset >= AccessWidth)
+        {
+            BitOffset -= AccessWidth;
+        }
+        else
+        {
+            if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
+            {
+                Value64 = (UINT64) Value32;
+                Status = AcpiOsWriteMemory ((ACPI_PHYSICAL_ADDRESS)
+                    Address + Index * ACPI_DIV_8 (AccessWidth),
+                    Value64, AccessWidth);
+            }
+            else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+            {
+                Status = AcpiHwWritePort ((ACPI_IO_ADDRESS)
+                    Address + Index * ACPI_DIV_8 (AccessWidth),
+                    Value32, AccessWidth);
+            }
+        }
+
+        /*
+         * Index * AccessWidth is ensured to be less than 32-bits by
+         * AcpiHwValidateRegister().
+         */
+        BitWidth -= BitWidth > AccessWidth ? AccessWidth : BitWidth;
+        Index++;
     }
 
     ACPI_DEBUG_PRINT ((ACPI_DB_IO,
         "Wrote: %8.8X width %2d   to %8.8X%8.8X (%s)\n",
-        Value, Reg->BitWidth, ACPI_FORMAT_UINT64 (Address),
+        Value, AccessWidth, ACPI_FORMAT_UINT64 (Address),
         AcpiUtGetRegionName (Reg->SpaceId)));
 
     return (Status);