ACPICA: Add 64-bit support to acpi_read and acpi_write

Needed by drivers for new ACPi tables.  Internal versions of
these functions still use 32-bit max transfers, in order to
minimize disruption and stack use for the standard ACPI registers
(FADT-based).

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>

8 files changed, 327 insertions, 105 deletions

diff --git a/drivers/acpi/acpica/achware.h b/drivers/acpi/acpica/achware.h
index 4afa3d8e0ef..36192f142fb 100644
--- a/drivers/acpi/acpica/achware.h
+++ b/drivers/acpi/acpica/achware.h
@@ -62,6 +62,14 @@ u32 acpi_hw_get_mode(void);
 /*
  * hwregs - ACPI Register I/O
  */
+acpi_status
+acpi_hw_validate_register(struct acpi_generic_address *reg,
+			  u8 max_bit_width, u64 *address);
+
+acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg);
+
+acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg);
+
 struct acpi_bit_register_info *acpi_hw_get_bit_register_info(u32 register_id);
 
 acpi_status acpi_hw_write_pm1_control(u32 pm1a_control, u32 pm1b_control);
diff --git a/drivers/acpi/acpica/evgpe.c b/drivers/acpi/acpica/evgpe.c
index b9d8ee69ca6..afacf4416c7 100644
--- a/drivers/acpi/acpica/evgpe.c
+++ b/drivers/acpi/acpica/evgpe.c
@@ -424,8 +424,8 @@ u32 acpi_ev_gpe_detect(struct acpi_gpe_xrupt_info * gpe_xrupt_list)
 			/* Read the Status Register */
 
 			status =
-			    acpi_read(&status_reg,
-				      &gpe_register_info->status_address);
+			    acpi_hw_read(&status_reg,
+					 &gpe_register_info->status_address);
 			if (ACPI_FAILURE(status)) {
 				goto unlock_and_exit;
 			}
@@ -433,8 +433,8 @@ u32 acpi_ev_gpe_detect(struct acpi_gpe_xrupt_info * gpe_xrupt_list)
 			/* Read the Enable Register */
 
 			status =
-			    acpi_read(&enable_reg,
-				      &gpe_register_info->enable_address);
+			    acpi_hw_read(&enable_reg,
+					 &gpe_register_info->enable_address);
 			if (ACPI_FAILURE(status)) {
 				goto unlock_and_exit;
 			}
diff --git a/drivers/acpi/acpica/evgpeblk.c b/drivers/acpi/acpica/evgpeblk.c
index 7b346363942..a60aaa7635f 100644
--- a/drivers/acpi/acpica/evgpeblk.c
+++ b/drivers/acpi/acpica/evgpeblk.c
@@ -843,14 +843,14 @@ acpi_ev_create_gpe_info_blocks(struct acpi_gpe_block_info *gpe_block)
 
 		/* Disable all GPEs within this register */
 
-		status = acpi_write(0x00, &this_register->enable_address);
+		status = acpi_hw_write(0x00, &this_register->enable_address);
 		if (ACPI_FAILURE(status)) {
 			goto error_exit;
 		}
 
 		/* Clear any pending GPE events within this register */
 
-		status = acpi_write(0xFF, &this_register->status_address);
+		status = acpi_hw_write(0xFF, &this_register->status_address);
 		if (ACPI_FAILURE(status)) {
 			goto error_exit;
 		}
diff --git a/drivers/acpi/acpica/hwgpe.c b/drivers/acpi/acpica/hwgpe.c
index d3b7e37c9ee..c28c41b3180 100644
--- a/drivers/acpi/acpica/hwgpe.c
+++ b/drivers/acpi/acpica/hwgpe.c
@@ -82,7 +82,7 @@ acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 
 	/* Get current value of the enable register that contains this GPE */
 
-	status = acpi_read(&enable_mask, &gpe_register_info->enable_address);
+	status = acpi_hw_read(&enable_mask, &gpe_register_info->enable_address);
 	if (ACPI_FAILURE(status)) {
 		return (status);
 	}
@@ -95,7 +95,7 @@ acpi_status acpi_hw_low_disable_gpe(struct acpi_gpe_event_info *gpe_event_info)
 
 	/* Write the updated enable mask */
 
-	status = acpi_write(enable_mask, &gpe_register_info->enable_address);
+	status = acpi_hw_write(enable_mask, &gpe_register_info->enable_address);
 	return (status);
 }
 
@@ -130,8 +130,8 @@ acpi_hw_write_gpe_enable_reg(struct acpi_gpe_event_info * gpe_event_info)
 
 	/* Write the entire GPE (runtime) enable register */
 
-	status = acpi_write(gpe_register_info->enable_for_run,
-			    &gpe_register_info->enable_address);
+	status = acpi_hw_write(gpe_register_info->enable_for_run,
+			       &gpe_register_info->enable_address);
 
 	return (status);
 }
@@ -163,8 +163,8 @@ acpi_status acpi_hw_clear_gpe(struct acpi_gpe_event_info * gpe_event_info)
 	 * Write a one to the appropriate bit in the status register to
 	 * clear this GPE.
 	 */
-	status = acpi_write(register_bit,
-			    &gpe_event_info->register_info->status_address);
+	status = acpi_hw_write(register_bit,
+			       &gpe_event_info->register_info->status_address);
 
 	return (status);
 }
@@ -222,7 +222,7 @@ acpi_hw_get_gpe_status(struct acpi_gpe_event_info * gpe_event_info,
 
 	/* GPE currently active (status bit == 1)? */
 
-	status = acpi_read(&in_byte, &gpe_register_info->status_address);
+	status = acpi_hw_read(&in_byte, &gpe_register_info->status_address);
 	if (ACPI_FAILURE(status)) {
 		goto unlock_and_exit;
 	}
@@ -266,8 +266,8 @@ acpi_hw_disable_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 		/* Disable all GPEs in this register */
 
 		status =
-		    acpi_write(0x00,
-			       &gpe_block->register_info[i].enable_address);
+		    acpi_hw_write(0x00,
+				  &gpe_block->register_info[i].enable_address);
 		if (ACPI_FAILURE(status)) {
 			return (status);
 		}
@@ -303,8 +303,8 @@ acpi_hw_clear_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 		/* Clear status on all GPEs in this register */
 
 		status =
-		    acpi_write(0xFF,
-			       &gpe_block->register_info[i].status_address);
+		    acpi_hw_write(0xFF,
+				  &gpe_block->register_info[i].status_address);
 		if (ACPI_FAILURE(status)) {
 			return (status);
 		}
@@ -345,9 +345,9 @@ acpi_hw_enable_runtime_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 
 		/* Enable all "runtime" GPEs in this register */
 
-		status = acpi_write(gpe_block->register_info[i].enable_for_run,
-				    &gpe_block->register_info[i].
-				    enable_address);
+		status =
+		    acpi_hw_write(gpe_block->register_info[i].enable_for_run,
+				  &gpe_block->register_info[i].enable_address);
 		if (ACPI_FAILURE(status)) {
 			return (status);
 		}
@@ -387,9 +387,9 @@ acpi_hw_enable_wakeup_gpe_block(struct acpi_gpe_xrupt_info *gpe_xrupt_info,
 
 		/* Enable all "wake" GPEs in this register */
 
-		status = acpi_write(gpe_block->register_info[i].enable_for_wake,
-				    &gpe_block->register_info[i].
-				    enable_address);
+		status =
+		    acpi_hw_write(gpe_block->register_info[i].enable_for_wake,
+				  &gpe_block->register_info[i].enable_address);
 		if (ACPI_FAILURE(status)) {
 			return (status);
 		}
diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 23d5505cb1f..15c9ed2be85 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -62,6 +62,184 @@ acpi_hw_write_multiple(u32 value,
 		       struct acpi_generic_address *register_a,
 		       struct acpi_generic_address *register_b);
 
+/******************************************************************************
+ *
+ * FUNCTION:    acpi_hw_validate_register
+ *
+ * PARAMETERS:  Reg                 - GAS register structure
+ *              max_bit_width       - Max bit_width supported (32 or 64)
+ *              Address             - Pointer to where the gas->address
+ *                                    is returned
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Validate the contents of a GAS register. Checks the GAS
+ *              pointer, Address, space_id, bit_width, and bit_offset.
+ *
+ ******************************************************************************/
+
+acpi_status
+acpi_hw_validate_register(struct acpi_generic_address *reg,
+			  u8 max_bit_width, u64 *address)
+{
+
+	/* Must have a valid pointer to a GAS structure */
+
+	if (!reg) {
+		return (AE_BAD_PARAMETER);
+	}
+
+	/*
+	 * Copy the target address. This handles possible alignment issues.
+	 * Address must not be null. A null address also indicates an optional
+	 * ACPI register that is not supported, so no error message.
+	 */
+	ACPI_MOVE_64_TO_64(address, &reg->address);
+	if (!(*address)) {
+		return (AE_BAD_ADDRESS);
+	}
+
+	/* Validate the space_iD */
+
+	if ((reg->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&
+	    (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) {
+		ACPI_ERROR((AE_INFO,
+			    "Unsupported address space: 0x%X", reg->space_id));
+		return (AE_SUPPORT);
+	}
+
+	/* Validate the bit_width */
+
+	if ((reg->bit_width != 8) &&
+	    (reg->bit_width != 16) &&
+	    (reg->bit_width != 32) && (reg->bit_width != max_bit_width)) {
+		ACPI_ERROR((AE_INFO,
+			    "Unsupported register bit width: 0x%X",
+			    reg->bit_width));
+		return (AE_SUPPORT);
+	}
+
+	/* Validate the bit_offset. Just a warning for now. */
+
+	if (reg->bit_offset != 0) {
+		ACPI_WARNING((AE_INFO,
+			      "Unsupported register bit offset: 0x%X",
+			      reg->bit_offset));
+	}
+
+	return (AE_OK);
+}
+
+/******************************************************************************
+ *
+ * FUNCTION:    acpi_hw_read
+ *
+ * PARAMETERS:  Value               - Where the value is returned
+ *              Reg                 - GAS register structure
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Read from either memory or IO space. This is a 32-bit max
+ *              version of acpi_read, used internally since the overhead of
+ *              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;
+	acpi_status status;
+
+	ACPI_FUNCTION_NAME(hw_read);
+
+	/* Validate contents of the GAS register */
+
+	status = acpi_hw_validate_register(reg, 32, &address);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	/* Initialize entire 32-bit return value to zero */
+
+	*value = 0;
+
+	/*
+	 * 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, value, reg->bit_width);
+	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+
+		status = acpi_hw_read_port((acpi_io_address)
+					   address, value, reg->bit_width);
+	}
+
+	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),
+			  acpi_ut_get_region_name(reg->space_id)));
+
+	return (status);
+}
+
+/******************************************************************************
+ *
+ * FUNCTION:    acpi_hw_write
+ *
+ * PARAMETERS:  Value               - Value to be written
+ *              Reg                 - GAS register structure
+ *
+ * RETURN:      Status
+ *
+ * DESCRIPTION: Write to either memory or IO space. This is a 32-bit max
+ *              version of acpi_write, used internally since the overhead of
+ *              64-bit values is not needed.
+ *
+ ******************************************************************************/
+
+acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg)
+{
+	u64 address;
+	acpi_status status;
+
+	ACPI_FUNCTION_NAME(hw_write);
+
+	/* Validate contents of the GAS register */
+
+	status = acpi_hw_validate_register(reg, 32, &address);
+	if (ACPI_FAILURE(status)) {
+		return (status);
+	}
+
+	/*
+	 * 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, 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);
+	}
+
+	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),
+			  acpi_ut_get_region_name(reg->space_id)));
+
+	return (status);
+}
+
 /*******************************************************************************
  *
  * FUNCTION:    acpi_hw_clear_acpi_status
@@ -152,15 +330,16 @@ acpi_status acpi_hw_write_pm1_control(u32 pm1a_control, u32 pm1b_control)
 
 	ACPI_FUNCTION_TRACE(hw_write_pm1_control);
 
-	status = acpi_write(pm1a_control, &acpi_gbl_FADT.xpm1a_control_block);
+	status =
+	    acpi_hw_write(pm1a_control, &acpi_gbl_FADT.xpm1a_control_block);
 	if (ACPI_FAILURE(status)) {
 		return_ACPI_STATUS(status);
 	}
 
 	if (acpi_gbl_FADT.xpm1b_control_block.address) {
 		status =
-		    acpi_write(pm1b_control,
-			       &acpi_gbl_FADT.xpm1b_control_block);
+		    acpi_hw_write(pm1b_control,
+				  &acpi_gbl_FADT.xpm1b_control_block);
 	}
 	return_ACPI_STATUS(status);
 }
@@ -218,12 +397,13 @@ acpi_hw_register_read(u32 register_id, u32 * return_value)
 
 	case ACPI_REGISTER_PM2_CONTROL:	/* 8-bit access */
 
-		status = acpi_read(&value, &acpi_gbl_FADT.xpm2_control_block);
+		status =
+		    acpi_hw_read(&value, &acpi_gbl_FADT.xpm2_control_block);
 		break;
 
 	case ACPI_REGISTER_PM_TIMER:	/* 32-bit access */
 
-		status = acpi_read(&value, &acpi_gbl_FADT.xpm_timer_block);
+		status = acpi_hw_read(&value, &acpi_gbl_FADT.xpm_timer_block);
 		break;
 
 	case ACPI_REGISTER_SMI_COMMAND_BLOCK:	/* 8-bit access */
@@ -340,7 +520,8 @@ acpi_status acpi_hw_register_write(u32 register_id, u32 value)
 		 * as per the ACPI spec.
 		 */
 		status =
-		    acpi_read(&read_value, &acpi_gbl_FADT.xpm2_control_block);
+		    acpi_hw_read(&read_value,
+				 &acpi_gbl_FADT.xpm2_control_block);
 		if (ACPI_FAILURE(status)) {
 			goto exit;
 		}
@@ -350,12 +531,13 @@ acpi_status acpi_hw_register_write(u32 register_id, u32 value)
 		ACPI_INSERT_BITS(value, ACPI_PM2_CONTROL_PRESERVED_BITS,
 				 read_value);
 
-		status = acpi_write(value, &acpi_gbl_FADT.xpm2_control_block);
+		status =
+		    acpi_hw_write(value, &acpi_gbl_FADT.xpm2_control_block);
 		break;
 
 	case ACPI_REGISTER_PM_TIMER:	/* 32-bit access */
 
-		status = acpi_write(value, &acpi_gbl_FADT.xpm_timer_block);
+		status = acpi_hw_write(value, &acpi_gbl_FADT.xpm_timer_block);
 		break;
 
 	case ACPI_REGISTER_SMI_COMMAND_BLOCK:	/* 8-bit access */
@@ -401,7 +583,7 @@ acpi_hw_read_multiple(u32 *value,
 
 	/* The first register is always required */
 
-	status = acpi_read(&value_a, register_a);
+	status = acpi_hw_read(&value_a, register_a);
 	if (ACPI_FAILURE(status)) {
 		return (status);
 	}
@@ -409,7 +591,7 @@ acpi_hw_read_multiple(u32 *value,
 	/* Second register is optional */
 
 	if (register_b->address) {
-		status = acpi_read(&value_b, register_b);
+		status = acpi_hw_read(&value_b, register_b);
 		if (ACPI_FAILURE(status)) {
 			return (status);
 		}
@@ -452,7 +634,7 @@ acpi_hw_write_multiple(u32 value,
 
 	/* The first register is always required */
 
-	status = acpi_write(value, register_a);
+	status = acpi_hw_write(value, register_a);
 	if (ACPI_FAILURE(status)) {
 		return (status);
 	}
@@ -470,7 +652,7 @@ acpi_hw_write_multiple(u32 value,
 	 * and writes have no side effects"
 	 */
 	if (register_b->address) {
-		status = acpi_write(value, register_b);
+		status = acpi_hw_write(value, register_b);
 	}
 
 	return (status);
diff --git a/drivers/acpi/acpica/hwtimer.c b/drivers/acpi/acpica/hwtimer.c
index b7f522c8f02..6b282e85d03 100644
--- a/drivers/acpi/acpica/hwtimer.c
+++ b/drivers/acpi/acpica/hwtimer.c
@@ -100,7 +100,7 @@ acpi_status acpi_get_timer(u32 * ticks)
 	}
 
 	status =
-	    acpi_hw_low_level_read(32, ticks, &acpi_gbl_FADT.xpm_timer_block);
+	    acpi_hw_read(ticks, &acpi_gbl_FADT.xpm_timer_block);
 
 	return_ACPI_STATUS(status);
 }
diff --git a/drivers/acpi/acpica/hwxface.c b/drivers/acpi/acpica/hwxface.c
index 9829979f2bd..4ead85f2921 100644
--- a/drivers/acpi/acpica/hwxface.c
+++ b/drivers/acpi/acpica/hwxface.c
@@ -80,7 +80,7 @@ acpi_status acpi_reset(void)
 
 	/* Write the reset value to the reset register */
 
-	status = acpi_write(acpi_gbl_FADT.reset_value, reset_reg);
+	status = acpi_hw_write(acpi_gbl_FADT.reset_value, reset_reg);
 	return_ACPI_STATUS(status);
 }
 
@@ -97,67 +97,92 @@ ACPI_EXPORT_SYMBOL(acpi_reset)
  *
  * DESCRIPTION: Read from either memory or IO space.
  *
+ * LIMITATIONS: <These limitations also apply to acpi_write>
+ *      bit_width must be exactly 8, 16, 32, or 64.
+ *      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_read(u32 *value, struct acpi_generic_address *reg)
+acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
 {
+	u32 value;
 	u32 width;
 	u64 address;
 	acpi_status status;
 
 	ACPI_FUNCTION_NAME(acpi_read);
 
-	/*
-	 * Must have a valid pointer to a GAS structure, and a non-zero address
-	 * within.
-	 */
-	if (!reg) {
+	if (!return_value) {
 		return (AE_BAD_PARAMETER);
 	}
 
-	/* Get a local copy of the address. Handles possible alignment issues */
+	/* Validate contents of the GAS register. Allow 64-bit transfers */
 
-	ACPI_MOVE_64_TO_64(&address, &reg->address);
-	if (!address) {
-		return (AE_BAD_ADDRESS);
+	status = acpi_hw_validate_register(reg, 64, &address);
+	if (ACPI_FAILURE(status)) {
+		return (status);
 	}
 
-	/* Supported widths are 8/16/32 */
-
 	width = reg->bit_width;
-	if ((width != 8) && (width != 16) && (width != 32)) {
-		return (AE_SUPPORT);
+	if (width == 64) {
+		width = 32;	/* Break into two 32-bit transfers */
 	}
 
-	/* Initialize entire 32-bit return value to zero */
+	/* Initialize entire 64-bit return value to zero */
 
-	*value = 0;
+	*return_value = 0;
+	value = 0;
 
 	/*
 	 * Two address spaces supported: Memory or IO. PCI_Config is
 	 * not supported here because the GAS structure is insufficient
 	 */
-	switch (reg->space_id) {
-	case ACPI_ADR_SPACE_SYSTEM_MEMORY:
+	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+		status = acpi_os_read_memory((acpi_physical_address)
+					     address, &value, width);
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
+		*return_value = value;
+
+		if (reg->bit_width == 64) {
 
-		status = acpi_os_read_memory((acpi_physical_address) address,
-					     value, width);
-		break;
+			/* Read the top 32 bits */
 
-	case ACPI_ADR_SPACE_SYSTEM_IO:
+			status = acpi_os_read_memory((acpi_physical_address)
+						     (address + 4), &value, 32);
+			if (ACPI_FAILURE(status)) {
+				return (status);
+			}
+			*return_value |= ((u64)value << 32);
+		}
+	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
 
-		status =
-		    acpi_hw_read_port((acpi_io_address) address, value, width);
-		break;
+		status = acpi_hw_read_port((acpi_io_address)
+					   address, &value, width);
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
+		*return_value = value;
 
-	default:
-		ACPI_ERROR((AE_INFO,
-			    "Unsupported address space: %X", reg->space_id));
-		return (AE_BAD_PARAMETER);
+		if (reg->bit_width == 64) {
+
+			/* Read the top 32 bits */
+
+			status = acpi_hw_read_port((acpi_io_address)
+						   (address + 4), &value, 32);
+			if (ACPI_FAILURE(status)) {
+				return (status);
+			}
+			*return_value |= ((u64)value << 32);
+		}
 	}
 
 	ACPI_DEBUG_PRINT((ACPI_DB_IO,
-			  "Read:  %8.8X width %2d from %8.8X%8.8X (%s)\n",
-			  *value, width, ACPI_FORMAT_UINT64(address),
+			  "Read:  %8.8X%8.8X width %2d from %8.8X%8.8X (%s)\n",
+			  ACPI_FORMAT_UINT64(*return_value), reg->bit_width,
+			  ACPI_FORMAT_UINT64(address),
 			  acpi_ut_get_region_name(reg->space_id)));
 
 	return (status);
@@ -169,7 +194,7 @@ ACPI_EXPORT_SYMBOL(acpi_read)
  *
  * FUNCTION:    acpi_write
  *
- * PARAMETERS:  Value               - To be written
+ * PARAMETERS:  Value               - Value to be written
  *              Reg                 - GAS register structure
  *
  * RETURN:      Status
@@ -177,7 +202,7 @@ ACPI_EXPORT_SYMBOL(acpi_read)
  * DESCRIPTION: Write to either memory or IO space.
  *
  ******************************************************************************/
-acpi_status acpi_write(u32 value, struct acpi_generic_address *reg)
+acpi_status acpi_write(u64 value, struct acpi_generic_address *reg)
 {
 	u32 width;
 	u64 address;
@@ -185,54 +210,61 @@ acpi_status acpi_write(u32 value, struct acpi_generic_address *reg)
 
 	ACPI_FUNCTION_NAME(acpi_write);
 
-	/*
-	 * Must have a valid pointer to a GAS structure, and a non-zero address
-	 * within.
-	 */
-	if (!reg) {
-		return (AE_BAD_PARAMETER);
-	}
+	/* Validate contents of the GAS register. Allow 64-bit transfers */
 
-	/* Get a local copy of the address. Handles possible alignment issues */
-
-	ACPI_MOVE_64_TO_64(&address, &reg->address);
-	if (!address) {
-		return (AE_BAD_ADDRESS);
+	status = acpi_hw_validate_register(reg, 64, &address);
+	if (ACPI_FAILURE(status)) {
+		return (status);
 	}
 
-	/* Supported widths are 8/16/32 */
-
 	width = reg->bit_width;
-	if ((width != 8) && (width != 16) && (width != 32)) {
-		return (AE_SUPPORT);
+	if (width == 64) {
+		width = 32;	/* Break into two 32-bit transfers */
 	}
 
 	/*
-	 * Two address spaces supported: Memory or IO.
-	 * PCI_Config is not supported here because the GAS struct is insufficient
+	 * Two address spaces supported: Memory or IO. PCI_Config is
+	 * not supported here because the GAS structure is insufficient
 	 */
-	switch (reg->space_id) {
-	case ACPI_ADR_SPACE_SYSTEM_MEMORY:
-
-		status = acpi_os_write_memory((acpi_physical_address) address,
-					      value, width);
-		break;
+	if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+		status = acpi_os_write_memory((acpi_physical_address)
+					      address, ACPI_LODWORD(value),
+					      width);
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
 
-	case ACPI_ADR_SPACE_SYSTEM_IO:
+		if (reg->bit_width == 64) {
+			status = acpi_os_write_memory((acpi_physical_address)
+						      (address + 4),
+						      ACPI_HIDWORD(value), 32);
+			if (ACPI_FAILURE(status)) {
+				return (status);
+			}
+		}
+	} else {		/* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
 
-		status = acpi_hw_write_port((acpi_io_address) address, value,
+		status = acpi_hw_write_port((acpi_io_address)
+					    address, ACPI_LODWORD(value),
 					    width);
-		break;
+		if (ACPI_FAILURE(status)) {
+			return (status);
+		}
 
-	default:
-		ACPI_ERROR((AE_INFO,
-			    "Unsupported address space: %X", reg->space_id));
-		return (AE_BAD_PARAMETER);
+		if (reg->bit_width == 64) {
+			status = acpi_hw_write_port((acpi_io_address)
+						    (address + 4),
+						    ACPI_HIDWORD(value), 32);
+			if (ACPI_FAILURE(status)) {
+				return (status);
+			}
+		}
 	}
 
 	ACPI_DEBUG_PRINT((ACPI_DB_IO,
-			  "Wrote: %8.8X width %2d   to %8.8X%8.8X (%s)\n",
-			  value, width, ACPI_FORMAT_UINT64(address),
+			  "Wrote: %8.8X%8.8X width %2d   to %8.8X%8.8X (%s)\n",
+			  ACPI_FORMAT_UINT64(value), reg->bit_width,
+			  ACPI_FORMAT_UINT64(address),
 			  acpi_ut_get_region_name(reg->space_id)));
 
 	return (status);
diff --git a/include/acpi/acpixf.h b/include/acpi/acpixf.h
index 2aecaa5cc06..b450a195319 100644
--- a/include/acpi/acpixf.h
+++ b/include/acpi/acpixf.h
@@ -360,9 +360,9 @@ acpi_status acpi_set_firmware_waking_vector(u32 physical_address);
 acpi_status acpi_set_firmware_waking_vector64(u64 physical_address);
 #endif
 
-acpi_status acpi_read(u32 *value, struct acpi_generic_address *reg);
+acpi_status acpi_read(u64 *value, struct acpi_generic_address *reg);
 
-acpi_status acpi_write(u32 value, struct acpi_generic_address *reg);
+acpi_status acpi_write(u64 value, struct acpi_generic_address *reg);
 
 acpi_status
 acpi_get_sleep_type_data(u8 sleep_state, u8 * slp_typ_a, u8 * slp_typ_b);