8 files changed, 327 insertions, 105 deletions

diff --git a/drivers/acpi/acpica/achware.h b/drivers/acpi/acpica/achware.h
index 4afa3d8e0efb..36192f142fbb 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 b9d8ee69ca6c..afacf4416c73 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 7b3463639422..a60aaa7635f3 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 d3b7e37c9eed..c28c41b3180b 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 23d5505cb1f7..15c9ed2be853 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 b7f522c8f023..6b282e85d039 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 9829979f2bdd..4ead85f29215 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 2aecaa5cc06c..b450a195319a 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);