1 files changed, 259 insertions, 32 deletions

diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 5ba0498412fd..0f18dbc9a37f 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -51,6 +51,10 @@ ACPI_MODULE_NAME("hwregs")
 
 #if (!ACPI_REDUCED_HARDWARE)
 /* Local Prototypes */
+static u8
+acpi_hw_get_access_bit_width(struct acpi_generic_address *reg,
+			     u8 max_bit_width);
+
 static acpi_status
 acpi_hw_read_multiple(u32 *value,
 		      struct acpi_generic_address *register_a,
@@ -65,6 +69,48 @@ acpi_hw_write_multiple(u32 value,
 
 /******************************************************************************
  *
+ * FUNCTION:    acpi_hw_get_access_bit_width
+ *
+ * PARAMETERS:  reg                 - GAS register structure
+ *              max_bit_width       - Max bit_width supported (32 or 64)
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Obtain optimal access bit width
+ *
+ ******************************************************************************/
+
+static u8
+acpi_hw_get_access_bit_width(struct acpi_generic_address *reg, u8 max_bit_width)
+{
+	u64 address;
+
+	if (!reg->access_width) {
+		/*
+		 * Detect old register descriptors where only the bit_width field
+		 * makes senses. The target address is copied to handle possible
+		 * alignment issues.
+		 */
+		ACPI_MOVE_64_TO_64(&address, &reg->address);
+		if (!reg->bit_offset && reg->bit_width &&
+		    ACPI_IS_POWER_OF_TWO(reg->bit_width) &&
+		    ACPI_IS_ALIGNED(reg->bit_width, 8) &&
+		    ACPI_IS_ALIGNED(address, reg->bit_width)) {
+			return (reg->bit_width);
+		} else {
+			if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+				return (32);
+			} else {
+				return (max_bit_width);
+			}
+		}
+	} else {
+		return (1 << (reg->access_width + 2));
+	}
+}
+
+/******************************************************************************
+ *
  * FUNCTION:    acpi_hw_validate_register
  *
  * PARAMETERS:  reg                 - GAS register structure
@@ -83,6 +129,8 @@ acpi_status
 acpi_hw_validate_register(struct acpi_generic_address *reg,
 			  u8 max_bit_width, u64 *address)
 {
+	u8 bit_width;
+	u8 access_width;
 
 	/* Must have a valid pointer to a GAS structure */
 
@@ -109,23 +157,25 @@ acpi_hw_validate_register(struct acpi_generic_address *reg,
 		return (AE_SUPPORT);
 	}
 
-	/* Validate the bit_width */
+	/* Validate the access_width */
 
-	if ((reg->bit_width != 8) &&
-	    (reg->bit_width != 16) &&
-	    (reg->bit_width != 32) && (reg->bit_width != max_bit_width)) {
+	if (reg->access_width > 4) {
 		ACPI_ERROR((AE_INFO,
-			    "Unsupported register bit width: 0x%X",
-			    reg->bit_width));
+			    "Unsupported register access width: 0x%X",
+			    reg->access_width));
 		return (AE_SUPPORT);
 	}
 
-	/* Validate the bit_offset. Just a warning for now. */
+	/* Validate the bit_width, convert access_width into number of bits */
 
-	if (reg->bit_offset != 0) {
+	access_width = acpi_hw_get_access_bit_width(reg, max_bit_width);
+	bit_width =
+	    ACPI_ROUND_UP(reg->bit_offset + reg->bit_width, access_width);
+	if (max_bit_width < bit_width) {
 		ACPI_WARNING((AE_INFO,
-			      "Unsupported register bit offset: 0x%X",
-			      reg->bit_offset));
+			      "Requested bit width 0x%X is smaller than register bit width 0x%X",
+			      max_bit_width, bit_width));
+		return (AE_SUPPORT);
 	}
 
 	return (AE_OK);
@@ -145,17 +195,19 @@ acpi_hw_validate_register(struct acpi_generic_address *reg,
  *              64-bit values is not needed.
  *
  * LIMITATIONS: <These limitations also apply to acpi_hw_write>
- *      bit_width must be exactly 8, 16, or 32.
  *      space_ID must be system_memory or system_IO.
- *      bit_offset and access_width are currently ignored, as there has
- *          not been a need to implement these.
  *
  ******************************************************************************/
 
 acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
 {
 	u64 address;
+	u8 access_width;
+	u32 bit_width;
+	u8 bit_offset;
 	u64 value64;
+	u32 value32;
+	u8 index;
 	acpi_status status;
 
 	ACPI_FUNCTION_NAME(hw_read);
@@ -167,28 +219,75 @@ acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
 		return (status);
 	}
 
-	/* Initialize entire 32-bit return value to zero */
-
+	/*
+	 * Initialize entire 32-bit return value to zero, convert access_width
+	 * into number of bits based
+	 */
 	*value = 0;
+	access_width = acpi_hw_get_access_bit_width(reg, 32);
+	bit_width = reg->bit_offset + reg->bit_width;
+	bit_offset = reg->bit_offset;
 
 	/*
 	 * Two address spaces supported: Memory or IO. PCI_Config is
 	 * not supported here because the GAS structure is insufficient
 	 */
-	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
-		status = acpi_os_read_memory((acpi_physical_address)
-					     address, &value64, reg->bit_width);
+	index = 0;
+	while (bit_width) {
+		if (bit_offset >= access_width) {
+			value32 = 0;
+			bit_offset -= access_width;
+		} else {
+			if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+				status =
+				    acpi_os_read_memory((acpi_physical_address)
+							address +
+							index *
+							ACPI_DIV_8
+							(access_width),
+							&value64, access_width);
+				value32 = (u32)value64;
+			} else {	/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+
+				status = acpi_hw_read_port((acpi_io_address)
+							   address +
+							   index *
+							   ACPI_DIV_8
+							   (access_width),
+							   &value32,
+							   access_width);
+			}
+
+			/*
+			 * Use offset style bit masks because:
+			 * bit_offset < access_width/bit_width < access_width, and
+			 * access_width is ensured to be less than 32-bits by
+			 * acpi_hw_validate_register().
+			 */
+			if (bit_offset) {
+				value32 &= ACPI_MASK_BITS_BELOW(bit_offset);
+				bit_offset = 0;
+			}
+			if (bit_width < access_width) {
+				value32 &= ACPI_MASK_BITS_ABOVE(bit_width);
+			}
+		}
 
-		*value = (u32)value64;
-	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+		/*
+		 * Use offset style bit writes because "Index * AccessWidth" is
+		 * ensured to be less than 32-bits by acpi_hw_validate_register().
+		 */
+		ACPI_SET_BITS(value, index * access_width,
+			      ACPI_MASK_BITS_ABOVE_32(access_width), value32);
 
-		status = acpi_hw_read_port((acpi_io_address)
-					   address, value, reg->bit_width);
+		bit_width -=
+		    bit_width > access_width ? access_width : bit_width;
+		index++;
 	}
 
 	ACPI_DEBUG_PRINT((ACPI_DB_IO,
 			  "Read:  %8.8X width %2d from %8.8X%8.8X (%s)\n",
-			  *value, reg->bit_width, ACPI_FORMAT_UINT64(address),
+			  *value, access_width, ACPI_FORMAT_UINT64(address),
 			  acpi_ut_get_region_name(reg->space_id)));
 
 	return (status);
@@ -212,6 +311,12 @@ acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
 acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg)
 {
 	u64 address;
+	u8 access_width;
+	u32 bit_width;
+	u8 bit_offset;
+	u64 value64;
+	u32 new_value32, old_value32;
+	u8 index;
 	acpi_status status;
 
 	ACPI_FUNCTION_NAME(hw_write);
@@ -223,23 +328,145 @@ acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg)
 		return (status);
 	}
 
+	/* Convert access_width into number of bits based */
+
+	access_width = acpi_hw_get_access_bit_width(reg, 32);
+	bit_width = reg->bit_offset + reg->bit_width;
+	bit_offset = reg->bit_offset;
+
 	/*
 	 * Two address spaces supported: Memory or IO. PCI_Config is
 	 * not supported here because the GAS structure is insufficient
 	 */
-	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
-		status = acpi_os_write_memory((acpi_physical_address)
-					      address, (u64)value,
-					      reg->bit_width);
-	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
-
-		status = acpi_hw_write_port((acpi_io_address)
-					    address, value, reg->bit_width);
+	index = 0;
+	while (bit_width) {
+		/*
+		 * Use offset style bit reads because "Index * AccessWidth" is
+		 * ensured to be less than 32-bits by acpi_hw_validate_register().
+		 */
+		new_value32 = ACPI_GET_BITS(&value, index * access_width,
+					    ACPI_MASK_BITS_ABOVE_32
+					    (access_width));
+
+		if (bit_offset >= access_width) {
+			bit_offset -= access_width;
+		} else {
+			/*
+			 * Use offset style bit masks because access_width is ensured
+			 * to be less than 32-bits by acpi_hw_validate_register() and
+			 * bit_offset/bit_width is less than access_width here.
+			 */
+			if (bit_offset) {
+				new_value32 &= ACPI_MASK_BITS_BELOW(bit_offset);
+			}
+			if (bit_width < access_width) {
+				new_value32 &= ACPI_MASK_BITS_ABOVE(bit_width);
+			}
+
+			if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+				if (bit_offset || bit_width < access_width) {
+					/*
+					 * Read old values in order not to modify the bits that
+					 * are beyond the register bit_width/bit_offset setting.
+					 */
+					status =
+					    acpi_os_read_memory((acpi_physical_address)
+								address +
+								index *
+								ACPI_DIV_8
+								(access_width),
+								&value64,
+								access_width);
+					old_value32 = (u32)value64;
+
+					/*
+					 * Use offset style bit masks because access_width is
+					 * ensured to be less than 32-bits by
+					 * acpi_hw_validate_register() and bit_offset/bit_width is
+					 * less than access_width here.
+					 */
+					if (bit_offset) {
+						old_value32 &=
+						    ACPI_MASK_BITS_ABOVE
+						    (bit_offset);
+						bit_offset = 0;
+					}
+					if (bit_width < access_width) {
+						old_value32 &=
+						    ACPI_MASK_BITS_BELOW
+						    (bit_width);
+					}
+
+					new_value32 |= old_value32;
+				}
+
+				value64 = (u64)new_value32;
+				status =
+				    acpi_os_write_memory((acpi_physical_address)
+							 address +
+							 index *
+							 ACPI_DIV_8
+							 (access_width),
+							 value64, access_width);
+			} else {	/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+
+				if (bit_offset || bit_width < access_width) {
+					/*
+					 * Read old values in order not to modify the bits that
+					 * are beyond the register bit_width/bit_offset setting.
+					 */
+					status =
+					    acpi_hw_read_port((acpi_io_address)
+							      address +
+							      index *
+							      ACPI_DIV_8
+							      (access_width),
+							      &old_value32,
+							      access_width);
+
+					/*
+					 * Use offset style bit masks because access_width is
+					 * ensured to be less than 32-bits by
+					 * acpi_hw_validate_register() and bit_offset/bit_width is
+					 * less than access_width here.
+					 */
+					if (bit_offset) {
+						old_value32 &=
+						    ACPI_MASK_BITS_ABOVE
+						    (bit_offset);
+						bit_offset = 0;
+					}
+					if (bit_width < access_width) {
+						old_value32 &=
+						    ACPI_MASK_BITS_BELOW
+						    (bit_width);
+					}
+
+					new_value32 |= old_value32;
+				}
+
+				status = acpi_hw_write_port((acpi_io_address)
+							    address +
+							    index *
+							    ACPI_DIV_8
+							    (access_width),
+							    new_value32,
+							    access_width);
+			}
+		}
+
+		/*
+		 * Index * access_width is ensured to be less than 32-bits by
+		 * acpi_hw_validate_register().
+		 */
+		bit_width -=
+		    bit_width > access_width ? access_width : bit_width;
+		index++;
 	}
 
 	ACPI_DEBUG_PRINT((ACPI_DB_IO,
 			  "Wrote: %8.8X width %2d   to %8.8X%8.8X (%s)\n",
-			  value, reg->bit_width, ACPI_FORMAT_UINT64(address),
+			  value, access_width, ACPI_FORMAT_UINT64(address),
 			  acpi_ut_get_region_name(reg->space_id)));
 
 	return (status);