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Optimize ACPI register locking.

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Removed locking for reads from the ACPI bit registers in PM1 Status,
Enable, Control, and PM2 Control. The lock is not required when
reading the single-bit registers. The AcpiGetRegisterUnlocked function
is no longer needed and has been removed. This will improve performance
for reads on these registers.
ACPICA BZ 760.
This commit is contained in:
Robert Moore 2009-02-10 08:43:05 -08:00
parent f21fd0d909
commit d258fbe313
2 changed files with 27 additions and 49 deletions
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71
source/components/hardware/hwxface.c
View File

@ -347,20 +347,31 @@ ACPI_EXPORT_SYMBOL (AcpiWrite)
/*******************************************************************************
*
* FUNCTION: AcpiGetRegisterUnlocked
* FUNCTION: AcpiGetRegister
*
* PARAMETERS: RegisterId - ID of ACPI BitRegister to access
* ReturnValue - Value that was read from the register
* PARAMETERS: RegisterId - ID of ACPI Bit Register to access
* ReturnValue - Value that was read from the register,
* normalized to bit position zero.
*
* RETURN: Status and the value read from specified Register. Value
* RETURN: Status and the value read from the specified Register. Value
* returned is normalized to bit0 (is shifted all the way right)
*
* DESCRIPTION: ACPI BitRegister read function. Does not acquire the HW lock.
*
* SUPPORTS: Bit fields in PM1 Status, PM1 Enable, PM1 Control, and
* PM2 Control.
*
* Note: The hardware lock is not required when reading the ACPI bit registers
* since almost all of them are single bit and it does not matter that
* the parent hardware register can be split across two physical
* registers. The only multi-bit field is SLP_TYP in the PM1 control
* register, but this field does not cross an 8-bit boundary (nor does
* it make much sense to actually read this field.)
*
******************************************************************************/
ACPI_STATUS
AcpiGetRegisterUnlocked (
AcpiGetRegister (
UINT32 RegisterId,
UINT32 *ReturnValue)
{
@ -369,7 +380,7 @@ AcpiGetRegisterUnlocked (
ACPI_STATUS Status;
ACPI_FUNCTION_TRACE (AcpiGetRegisterUnlocked);
ACPI_FUNCTION_TRACE (AcpiGetRegister);
/* Get the info structure corresponding to the requested ACPI Register */
@ -380,7 +391,7 @@ AcpiGetRegisterUnlocked (
return_ACPI_STATUS (AE_BAD_PARAMETER);
}
/* Read from the register */
/* Read the entire parent register */
Status = AcpiHwRegisterRead (BitRegInfo->ParentRegister,
&RegisterValue);
@ -401,39 +412,6 @@ AcpiGetRegisterUnlocked (
return_ACPI_STATUS (Status);
}
ACPI_EXPORT_SYMBOL (AcpiGetRegisterUnlocked)
/*******************************************************************************
*
* FUNCTION: AcpiGetRegister
*
* PARAMETERS: RegisterId - ID of ACPI BitRegister to access
* ReturnValue - Value that was read from the register
*
* RETURN: Status and the value read from specified Register. Value
* returned is normalized to bit0 (is shifted all the way right)
*
* DESCRIPTION: ACPI BitRegister read function.
*
******************************************************************************/
ACPI_STATUS
AcpiGetRegister (
UINT32 RegisterId,
UINT32 *ReturnValue)
{
ACPI_STATUS Status;
ACPI_CPU_FLAGS Flags;
Flags = AcpiOsAcquireLock (AcpiGbl_HardwareLock);
Status = AcpiGetRegisterUnlocked (RegisterId, ReturnValue);
AcpiOsReleaseLock (AcpiGbl_HardwareLock, Flags);
return (Status);
}
ACPI_EXPORT_SYMBOL (AcpiGetRegister)
@ -441,13 +419,18 @@ ACPI_EXPORT_SYMBOL (AcpiGetRegister)
*
* FUNCTION: AcpiSetRegister
*
* PARAMETERS: RegisterId - ID of ACPI BitRegister to access
* Value - (only used on write) value to write to the
* Register, NOT pre-normalized to the bit pos
* PARAMETERS: RegisterId - ID of ACPI Bit Register to access
* Value - Value to write to the register, in bit
* position zero. The bit is automaticallly
* shifted to the correct position.
*
* RETURN: Status
*
* DESCRIPTION: ACPI Bit Register write function.
* DESCRIPTION: ACPI Bit Register write function. Acquires the hardware lock
* since most operations require a read/modify/write sequence.
*
* SUPPORTS: Bit fields in PM1 Status, PM1 Enable, PM1 Control, and
* PM2 Control.
*
******************************************************************************/

5
source/include/acpixf.h
View File

@ -568,11 +568,6 @@ AcpiGetRegister (
UINT32 RegisterId,
UINT32 *ReturnValue);
ACPI_STATUS
AcpiGetRegisterUnlocked (
UINT32 RegisterId,
UINT32 *ReturnValue);
ACPI_STATUS
AcpiSetRegister (
UINT32 RegisterId,