/*******************************************************************************
*
* Module Name: hwregs - Read/write access functions for the various ACPI
* control and status registers.
*
******************************************************************************/
/*
* Copyright (C) 2000 - 2018, Intel Corp.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions, and the following disclaimer,
* without modification.
* 2. Redistributions in binary form must reproduce at minimum a disclaimer
* substantially similar to the "NO WARRANTY" disclaimer below
* ("Disclaimer") and any redistribution must be conditioned upon
* including a substantially similar Disclaimer requirement for further
* binary redistribution.
* 3. Neither the names of the above-listed copyright holders nor the names
* of any contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* Alternatively, this software may be distributed under the terms of the
* GNU General Public License ("GPL") version 2 as published by the Free
* Software Foundation.
*
* NO WARRANTY
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGES.
*/
#include "acpi.h"
#include "accommon.h"
#include "acevents.h"
#define _COMPONENT ACPI_HARDWARE
ACPI_MODULE_NAME ("hwregs")
#if (!ACPI_REDUCED_HARDWARE)
/* Local Prototypes */
static UINT8
AcpiHwGetAccessBitWidth (
UINT64 Address,
ACPI_GENERIC_ADDRESS *Reg,
UINT8 MaxBitWidth);
static ACPI_STATUS
AcpiHwReadMultiple (
UINT32 *Value,
ACPI_GENERIC_ADDRESS *RegisterA,
ACPI_GENERIC_ADDRESS *RegisterB);
static ACPI_STATUS
AcpiHwWriteMultiple (
UINT32 Value,
ACPI_GENERIC_ADDRESS *RegisterA,
ACPI_GENERIC_ADDRESS *RegisterB);
#endif /* !ACPI_REDUCED_HARDWARE */
/******************************************************************************
*
* 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 = ACPI_ACCESS_BIT_WIDTH (Reg->AccessWidth);
}
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
* MaxBitWidth - Max BitWidth 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, SpaceId, BitWidth, and BitOffset.
*
******************************************************************************/
ACPI_STATUS
AcpiHwValidateRegister (
ACPI_GENERIC_ADDRESS *Reg,
UINT8 MaxBitWidth,
UINT64 *Address)
{
UINT8 BitWidth;
UINT8 AccessWidth;
/* 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.
*/
*Address = Reg->Address;
if (!(*Address))
{
return (AE_BAD_ADDRESS);
}
/* Validate the SpaceID */
if ((Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_MEMORY) &&
(Reg->SpaceId != ACPI_ADR_SPACE_SYSTEM_IO))
{
ACPI_ERROR ((AE_INFO,
"Unsupported address space: 0x%X", Reg->SpaceId));
return (AE_SUPPORT);
}
/* Validate the AccessWidth */
if (Reg->AccessWidth > 4)
{
ACPI_ERROR ((AE_INFO,
"Unsupported register access width: 0x%X", Reg->AccessWidth));
return (AE_SUPPORT);
}
/* Validate the BitWidth, convert AccessWidth into number of bits */
AccessWidth = AcpiHwGetAccessBitWidth (*Address, Reg, MaxBitWidth);
BitWidth = ACPI_ROUND_UP (Reg->BitOffset + Reg->BitWidth, AccessWidth);
if (MaxBitWidth < BitWidth)
{
ACPI_WARNING ((AE_INFO,
"Requested bit width 0x%X is smaller than register bit width 0x%X",
MaxBitWidth, BitWidth));
return (AE_SUPPORT);
}
return (AE_OK);
}
/******************************************************************************
*
* FUNCTION: AcpiHwRead
*
* PARAMETERS: Value - Where the value is returned
* Reg - GAS register structure
*
* RETURN: Status
*
* DESCRIPTION: Read from either memory or IO space. This is a 64-bit max
* version of AcpiRead.
*
* LIMITATIONS: <These limitations also apply to AcpiHwWrite>
* SpaceID must be SystemMemory or SystemIO.
*
******************************************************************************/
ACPI_STATUS
AcpiHwRead (
UINT64 *Value,
ACPI_GENERIC_ADDRESS *Reg)
{
UINT64 Address;
UINT8 AccessWidth;
UINT32 BitWidth;
UINT8 BitOffset;
UINT64 Value64;
UINT32 Value32;
UINT8 Index;
ACPI_STATUS Status;
ACPI_FUNCTION_NAME (HwRead);
/* Validate contents of the GAS register */
Status = AcpiHwValidateRegister (Reg, 64, &Address);
if (ACPI_FAILURE (Status))
{
return (Status);
}
/*
* Initialize entire 64-bit return value to zero, convert AccessWidth
* into number of bits based
*/
*Value = 0;
AccessWidth = AcpiHwGetAccessBitWidth (Address, Reg, 64);
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
*/
Index = 0;
while (BitWidth)
{
if (BitOffset >= AccessWidth)
{
Value64 = 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);
}
else /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
{
Status = AcpiHwReadPort ((ACPI_IO_ADDRESS)
Address + Index * ACPI_DIV_8 (AccessWidth),
&Value32, AccessWidth);
Value64 = (UINT64) Value32;
}
}
/*
* Use offset style bit writes because "Index * AccessWidth" is
* ensured to be less than 64-bits by AcpiHwValidateRegister().
*/
ACPI_SET_BITS (Value, Index * AccessWidth,
ACPI_MASK_BITS_ABOVE_64 (AccessWidth), Value64);
BitWidth -= BitWidth > AccessWidth ? AccessWidth : BitWidth;
Index++;
}
ACPI_DEBUG_PRINT ((ACPI_DB_IO,
"Read: %8.8X%8.8X width %2d from %8.8X%8.8X (%s)\n",
ACPI_FORMAT_UINT64 (*Value), AccessWidth,
ACPI_FORMAT_UINT64 (Address), AcpiUtGetRegionName (Reg->SpaceId)));
return (Status);
}
/******************************************************************************
*
* FUNCTION: AcpiHwWrite
*
* PARAMETERS: Value - Value to be written
* Reg - GAS register structure
*
* RETURN: Status
*
* DESCRIPTION: Write to either memory or IO space. This is a 64-bit max
* version of AcpiWrite.
*
******************************************************************************/
ACPI_STATUS
AcpiHwWrite (
UINT64 Value,
ACPI_GENERIC_ADDRESS *Reg)
{
UINT64 Address;
UINT8 AccessWidth;
UINT32 BitWidth;
UINT8 BitOffset;
UINT64 Value64;
UINT8 Index;
ACPI_STATUS Status;
ACPI_FUNCTION_NAME (HwWrite);
/* Validate contents of the GAS register */
Status = AcpiHwValidateRegister (Reg, 64, &Address);
if (ACPI_FAILURE (Status))
{
return (Status);
}
/* Convert AccessWidth into number of bits based */
AccessWidth = AcpiHwGetAccessBitWidth (Address, Reg, 64);
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
*/
Index = 0;
while (BitWidth)
{
/*
* Use offset style bit reads because "Index * AccessWidth" is
* ensured to be less than 64-bits by AcpiHwValidateRegister().
*/
Value64 = ACPI_GET_BITS (&Value, Index * AccessWidth,
ACPI_MASK_BITS_ABOVE_64 (AccessWidth));
if (BitOffset >= AccessWidth)
{
BitOffset -= AccessWidth;
}
else
{
if (Reg->SpaceId == ACPI_ADR_SPACE_SYSTEM_MEMORY)
{
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),
(UINT32) Value64, 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%8.8X width %2d to %8.8X%8.8X (%s)\n",
ACPI_FORMAT_UINT64 (Value), AccessWidth,
ACPI_FORMAT_UINT64 (Address), AcpiUtGetRegionName (Reg->SpaceId)));
return (Status);
}
#if (!ACPI_REDUCED_HARDWARE)
/*******************************************************************************
*
* FUNCTION: AcpiHwClearAcpiStatus
*
* PARAMETERS: None
*
* RETURN: Status
*
* DESCRIPTION: Clears all fixed and general purpose status bits
*
******************************************************************************/
ACPI_STATUS
AcpiHwClearAcpiStatus (
void)
{
ACPI_STATUS Status;
ACPI_CPU_FLAGS LockFlags = 0;
ACPI_FUNCTION_TRACE (HwClearAcpiStatus);
ACPI_DEBUG_PRINT ((ACPI_DB_IO, "About to write %04X to %8.8X%8.8X\n",
ACPI_BITMASK_ALL_FIXED_STATUS,
ACPI_FORMAT_UINT64 (AcpiGbl_XPm1aStatus.Address)));
LockFlags = AcpiOsAcquireLock (AcpiGbl_HardwareLock);
/* Clear the fixed events in PM1 A/B */
Status = AcpiHwRegisterWrite (ACPI_REGISTER_PM1_STATUS,
ACPI_BITMASK_ALL_FIXED_STATUS);
AcpiOsReleaseLock (AcpiGbl_HardwareLock, LockFlags);
if (ACPI_FAILURE (Status))
{
goto Exit;
}
/* Clear the GPE Bits in all GPE registers in all GPE blocks */
Status = AcpiEvWalkGpeList (AcpiHwClearGpeBlock, NULL);
Exit:
return_ACPI_STATUS (Status);
}
/*******************************************************************************
*
* FUNCTION: AcpiHwGetBitRegisterInfo
*
* PARAMETERS: RegisterId - Index of ACPI Register to access
*
* RETURN: The bitmask to be used when accessing the register
*
* DESCRIPTION: Map RegisterId into a register bitmask.
*
******************************************************************************/
ACPI_BIT_REGISTER_INFO *
AcpiHwGetBitRegisterInfo (
UINT32 RegisterId)
{
ACPI_FUNCTION_ENTRY ();
if (RegisterId > ACPI_BITREG_MAX)
{
ACPI_ERROR ((AE_INFO, "Invalid BitRegister ID: 0x%X", RegisterId));
return (NULL);
}
return (&AcpiGbl_BitRegisterInfo[RegisterId]);
}
/******************************************************************************
*
* FUNCTION: AcpiHwWritePm1Control
*
* PARAMETERS: Pm1aControl - Value to be written to PM1A control
* Pm1bControl - Value to be written to PM1B control
*
* RETURN: Status
*
* DESCRIPTION: Write the PM1 A/B control registers. These registers are
* different than than the PM1 A/B status and enable registers
* in that different values can be written to the A/B registers.
* Most notably, the SLP_TYP bits can be different, as per the
* values returned from the _Sx predefined methods.
*
******************************************************************************/
ACPI_STATUS
AcpiHwWritePm1Control (
UINT32 Pm1aControl,
UINT32 Pm1bControl)
{
ACPI_STATUS Status;
ACPI_FUNCTION_TRACE (HwWritePm1Control);
Status = AcpiHwWrite (Pm1aControl, &AcpiGbl_FADT.XPm1aControlBlock);
if (ACPI_FAILURE (Status))
{
return_ACPI_STATUS (Status);
}
if (AcpiGbl_FADT.XPm1bControlBlock.Address)
{
Status = AcpiHwWrite (Pm1bControl, &AcpiGbl_FADT.XPm1bControlBlock);
}
return_ACPI_STATUS (Status);
}
/******************************************************************************
*
* FUNCTION: AcpiHwRegisterRead
*
* PARAMETERS: RegisterId - ACPI Register ID
* ReturnValue - Where the register value is returned
*
* RETURN: Status and the value read.
*
* DESCRIPTION: Read from the specified ACPI register
*
******************************************************************************/
ACPI_STATUS
AcpiHwRegisterRead (
UINT32 RegisterId,
UINT32 *ReturnValue)
{
UINT32 Value = 0;
UINT64 Value64;
ACPI_STATUS Status;
ACPI_FUNCTION_TRACE (HwRegisterRead);
switch (RegisterId)
{
case ACPI_REGISTER_PM1_STATUS: /* PM1 A/B: 16-bit access each */
Status = AcpiHwReadMultiple (&Value,
&AcpiGbl_XPm1aStatus,
&AcpiGbl_XPm1bStatus);
break;
case ACPI_REGISTER_PM1_ENABLE: /* PM1 A/B: 16-bit access each */
Status = AcpiHwReadMultiple (&Value,
&AcpiGbl_XPm1aEnable,
&AcpiGbl_XPm1bEnable);
break;
case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */
Status = AcpiHwReadMultiple (&Value,
&AcpiGbl_FADT.XPm1aControlBlock,
&AcpiGbl_FADT.XPm1bControlBlock);
/*
* Zero the write-only bits. From the ACPI specification, "Hardware
* Write-Only Bits": "Upon reads to registers with write-only bits,
* software masks out all write-only bits."
*/
Value &= ~ACPI_PM1_CONTROL_WRITEONLY_BITS;
break;
case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */
Status = AcpiHwRead (&Value64, &AcpiGbl_FADT.XPm2ControlBlock);
Value = (UINT32) Value64;
break;
case ACPI_REGISTER_PM_TIMER: /* 32-bit access */
Status = AcpiHwRead (&Value64, &AcpiGbl_FADT.XPmTimerBlock);
Value = (UINT32) Value64;
break;
case ACPI_REGISTER_SMI_COMMAND_BLOCK: /* 8-bit access */
Status = AcpiHwReadPort (AcpiGbl_FADT.SmiCommand, &Value, 8);
break;
default:
ACPI_ERROR ((AE_INFO, "Unknown Register ID: 0x%X",
RegisterId));
Status = AE_BAD_PARAMETER;
break;
}
if (ACPI_SUCCESS (Status))
{
*ReturnValue = (UINT32) Value;
}
return_ACPI_STATUS (Status);
}
/******************************************************************************
*
* FUNCTION: AcpiHwRegisterWrite
*
* PARAMETERS: RegisterId - ACPI Register ID
* Value - The value to write
*
* RETURN: Status
*
* DESCRIPTION: Write to the specified ACPI register
*
* NOTE: In accordance with the ACPI specification, this function automatically
* preserves the value of the following bits, meaning that these bits cannot be
* changed via this interface:
*
* PM1_CONTROL[0] = SCI_EN
* PM1_CONTROL[9]
* PM1_STATUS[11]
*
* ACPI References:
* 1) Hardware Ignored Bits: When software writes to a register with ignored
* bit fields, it preserves the ignored bit fields
* 2) SCI_EN: OSPM always preserves this bit position
*
******************************************************************************/
ACPI_STATUS
AcpiHwRegisterWrite (
UINT32 RegisterId,
UINT32 Value)
{
ACPI_STATUS Status;
UINT32 ReadValue;
UINT64 ReadValue64;
ACPI_FUNCTION_TRACE (HwRegisterWrite);
switch (RegisterId)
{
case ACPI_REGISTER_PM1_STATUS: /* PM1 A/B: 16-bit access each */
/*
* Handle the "ignored" bit in PM1 Status. According to the ACPI
* specification, ignored bits are to be preserved when writing.
* Normally, this would mean a read/modify/write sequence. However,
* preserving a bit in the status register is different. Writing a
* one clears the status, and writing a zero preserves the status.
* Therefore, we must always write zero to the ignored bit.
*
* This behavior is clarified in the ACPI 4.0 specification.
*/
Value &= ~ACPI_PM1_STATUS_PRESERVED_BITS;
Status = AcpiHwWriteMultiple (Value,
&AcpiGbl_XPm1aStatus,
&AcpiGbl_XPm1bStatus);
break;
case ACPI_REGISTER_PM1_ENABLE: /* PM1 A/B: 16-bit access each */
Status = AcpiHwWriteMultiple (Value,
&AcpiGbl_XPm1aEnable,
&AcpiGbl_XPm1bEnable);
break;
case ACPI_REGISTER_PM1_CONTROL: /* PM1 A/B: 16-bit access each */
/*
* Perform a read first to preserve certain bits (per ACPI spec)
* Note: This includes SCI_EN, we never want to change this bit
*/
Status = AcpiHwReadMultiple (&ReadValue,
&AcpiGbl_FADT.XPm1aControlBlock,
&AcpiGbl_FADT.XPm1bControlBlock);
if (ACPI_FAILURE (Status))
{
goto Exit;
}
/* Insert the bits to be preserved */
ACPI_INSERT_BITS (Value, ACPI_PM1_CONTROL_PRESERVED_BITS, ReadValue);
/* Now we can write the data */
Status = AcpiHwWriteMultiple (Value,
&AcpiGbl_FADT.XPm1aControlBlock,
&AcpiGbl_FADT.XPm1bControlBlock);
break;
case ACPI_REGISTER_PM2_CONTROL: /* 8-bit access */
/*
* For control registers, all reserved bits must be preserved,
* as per the ACPI spec.
*/
Status = AcpiHwRead (&ReadValue64, &AcpiGbl_FADT.XPm2ControlBlock);
if (ACPI_FAILURE (Status))
{
goto Exit;
}
ReadValue = (UINT32) ReadValue64;
/* Insert the bits to be preserved */
ACPI_INSERT_BITS (Value, ACPI_PM2_CONTROL_PRESERVED_BITS, ReadValue);
Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPm2ControlBlock);
break;
case ACPI_REGISTER_PM_TIMER: /* 32-bit access */
Status = AcpiHwWrite (Value, &AcpiGbl_FADT.XPmTimerBlock);
break;
case ACPI_REGISTER_SMI_COMMAND_BLOCK: /* 8-bit access */
/* SMI_CMD is currently always in IO space */
Status = AcpiHwWritePort (AcpiGbl_FADT.SmiCommand, Value, 8);
break;
default:
ACPI_ERROR ((AE_INFO, "Unknown Register ID: 0x%X",
RegisterId));
Status = AE_BAD_PARAMETER;
break;
}
Exit:
return_ACPI_STATUS (Status);
}
/******************************************************************************
*
* FUNCTION: AcpiHwReadMultiple
*
* PARAMETERS: Value - Where the register value is returned
* RegisterA - First ACPI register (required)
* RegisterB - Second ACPI register (optional)
*
* RETURN: Status
*
* DESCRIPTION: Read from the specified two-part ACPI register (such as PM1 A/B)
*
******************************************************************************/
static ACPI_STATUS
AcpiHwReadMultiple (
UINT32 *Value,
ACPI_GENERIC_ADDRESS *RegisterA,
ACPI_GENERIC_ADDRESS *RegisterB)
{
UINT32 ValueA = 0;
UINT32 ValueB = 0;
UINT64 Value64;
ACPI_STATUS Status;
/* The first register is always required */
Status = AcpiHwRead (&Value64, RegisterA);
if (ACPI_FAILURE (Status))
{
return (Status);
}
ValueA = (UINT32) Value64;
/* Second register is optional */
if (RegisterB->Address)
{
Status = AcpiHwRead (&Value64, RegisterB);
if (ACPI_FAILURE (Status))
{
return (Status);
}
ValueB = (UINT32) Value64;
}
/*
* OR the two return values together. No shifting or masking is necessary,
* because of how the PM1 registers are defined in the ACPI specification:
*
* "Although the bits can be split between the two register blocks (each
* register block has a unique pointer within the FADT), the bit positions
* are maintained. The register block with unimplemented bits (that is,
* those implemented in the other register block) always returns zeros,
* and writes have no side effects"
*/
*Value = (ValueA | ValueB);
return (AE_OK);
}
/******************************************************************************
*
* FUNCTION: AcpiHwWriteMultiple
*
* PARAMETERS: Value - The value to write
* RegisterA - First ACPI register (required)
* RegisterB - Second ACPI register (optional)
*
* RETURN: Status
*
* DESCRIPTION: Write to the specified two-part ACPI register (such as PM1 A/B)
*
******************************************************************************/
static ACPI_STATUS
AcpiHwWriteMultiple (
UINT32 Value,
ACPI_GENERIC_ADDRESS *RegisterA,
ACPI_GENERIC_ADDRESS *RegisterB)
{
ACPI_STATUS Status;
/* The first register is always required */
Status = AcpiHwWrite (Value, RegisterA);
if (ACPI_FAILURE (Status))
{
return (Status);
}
/*
* Second register is optional
*
* No bit shifting or clearing is necessary, because of how the PM1
* registers are defined in the ACPI specification:
*
* "Although the bits can be split between the two register blocks (each
* register block has a unique pointer within the FADT), the bit positions
* are maintained. The register block with unimplemented bits (that is,
* those implemented in the other register block) always returns zeros,
* and writes have no side effects"
*/
if (RegisterB->Address)
{
Status = AcpiHwWrite (Value, RegisterB);
}
return (Status);
}
#endif /* !ACPI_REDUCED_HARDWARE */