Commit 9892dd23 authored by Bob Moore's avatar Bob Moore Committed by Len Brown
Browse files

ACPICA: Optimize ACPI register locking

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 acpi_get_register_unlocked
function is no longer needed and has been removed. This will
improve performance for reads on these registers.  ACPICA BZ 760.

http://www.acpica.org/bugzilla/show_bug.cgi?id=760

Signed-off-by: default avatarBob Moore <robert.moore@intel.com>
Signed-off-by: default avatarLin Ming <ming.m.lin@intel.com>
Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parent ec41f193
......@@ -365,7 +365,7 @@ acpi_status asmlinkage acpi_enter_sleep_state(u8 sleep_state)
/* Wait until we enter sleep state */
do {
status = acpi_get_register_unlocked(ACPI_BITREG_WAKE_STATUS,
status = acpi_get_register(ACPI_BITREG_WAKE_STATUS,
&in_value);
if (ACPI_FAILURE(status)) {
return_ACPI_STATUS(status);
......
......@@ -242,24 +242,35 @@ ACPI_EXPORT_SYMBOL(acpi_write)
/*******************************************************************************
*
* FUNCTION: acpi_get_register_unlocked
* FUNCTION: acpi_get_register
*
* PARAMETERS: register_id - ID of ACPI bit_register to access
* return_value - Value that was read from the register
* PARAMETERS: register_id - ID of ACPI Bit Register to access
* return_value - 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 bit_register 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 acpi_get_register_unlocked(u32 register_id, u32 *return_value)
acpi_status acpi_get_register(u32 register_id, u32 *return_value)
{
u32 register_value = 0;
struct acpi_bit_register_info *bit_reg_info;
acpi_status status;
ACPI_FUNCTION_TRACE(acpi_get_register_unlocked);
ACPI_FUNCTION_TRACE(acpi_get_register);
/* Get the info structure corresponding to the requested ACPI Register */
......@@ -268,7 +279,7 @@ acpi_status acpi_get_register_unlocked(u32 register_id, u32 *return_value)
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
/* Read from the register */
/* Read the entire parent register */
status = acpi_hw_register_read(bit_reg_info->parent_register,
&register_value);
......@@ -291,46 +302,24 @@ acpi_status acpi_get_register_unlocked(u32 register_id, u32 *return_value)
return_ACPI_STATUS(status);
}
ACPI_EXPORT_SYMBOL(acpi_get_register_unlocked)
/*******************************************************************************
*
* FUNCTION: acpi_get_register
*
* PARAMETERS: register_id - ID of ACPI bit_register to access
* return_value - 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 bit_register read function.
*
******************************************************************************/
acpi_status acpi_get_register(u32 register_id, u32 *return_value)
{
acpi_status status;
acpi_cpu_flags flags;
flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);
status = acpi_get_register_unlocked(register_id, return_value);
acpi_os_release_lock(acpi_gbl_hardware_lock, flags);
return (status);
}
ACPI_EXPORT_SYMBOL(acpi_get_register)
/*******************************************************************************
*
* FUNCTION: acpi_set_register
*
* PARAMETERS: register_id - ID of ACPI bit_register to access
* Value - (only used on write) value to write to the
* Register, NOT pre-normalized to the bit pos
* PARAMETERS: register_id - 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.
*
******************************************************************************/
acpi_status acpi_set_register(u32 register_id, u32 value)
......
......@@ -800,7 +800,7 @@ static int acpi_idle_bm_check(void)
{
u32 bm_status = 0;
acpi_get_register_unlocked(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
acpi_get_register(ACPI_BITREG_BUS_MASTER_STATUS, &bm_status);
if (bm_status)
acpi_set_register(ACPI_BITREG_BUS_MASTER_STATUS, 1);
/*
......
......@@ -347,8 +347,6 @@ acpi_status acpi_reset(void);
acpi_status acpi_get_register(u32 register_id, u32 * return_value);
acpi_status acpi_get_register_unlocked(u32 register_id, u32 *return_value);
acpi_status acpi_set_register(u32 register_id, u32 value);
acpi_status acpi_set_firmware_waking_vector(u32 physical_address);
......
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