[PATCH 36/98] ACPICA: Restructure bit register access functions

Len Brown
2009-03-28T04:32:45Z

From: Bob Moore <robert.moore@intel.com>

Update code for acpi_read_bit_register and acpi_write_bit_register.
Simplified code path, condensed duplicate code.

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>
---
drivers/acpi/acpica/hwxface.c | 177 ++++++++++++++--------------------------
1 files changed, 62 insertions(+), 115 deletions(-)

diff --git a/drivers/acpi/acpica/hwxface.c b/drivers/acpi/acpica/hwxface.c
index 529251c..caad516 100644
--- a/drivers/acpi/acpica/hwxface.c
+++ b/drivers/acpi/acpica/hwxface.c
@@ -133,8 +133,8 @@ acpi_status acpi_read(u32 *value, struct acpi_generic_address *reg)
*value = 0;

/*
- * 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:
@@ -266,11 +266,12 @@ ACPI_EXPORT_SYMBOL(acpi_write)
******************************************************************************/
acpi_status acpi_read_bit_register(u32 register_id, u32 *return_value)
{
- u32 register_value = 0;
struct acpi_bit_register_info *bit_reg_info;
+ u32 register_value;
+ u32 value;
acpi_status status;

- ACPI_FUNCTION_TRACE(acpi_read_bit_register);
+ ACPI_FUNCTION_TRACE_U32(acpi_read_bit_register, register_id);

/* Get the info structure corresponding to the requested ACPI Register */

@@ -283,23 +284,22 @@ acpi_status acpi_read_bit_register(u32 register_id, u32 *return_value)

status = acpi_hw_register_read(bit_reg_info->parent_register,
&register_value);
+ if (ACPI_FAILURE(status)) {
+ return_ACPI_STATUS(status);
+ }

- if (ACPI_SUCCESS(status)) {
-
- /* Normalize the value that was read */
-
- register_value =
- ((register_value & bit_reg_info->access_bit_mask)
- >> bit_reg_info->bit_position);
+ /* Normalize the value that was read, mask off other bits */

- *return_value = register_value;
+ value = ((register_value & bit_reg_info->access_bit_mask)
+ >> bit_reg_info->bit_position);

- ACPI_DEBUG_PRINT((ACPI_DB_IO, "Read value %8.8X register %X\n",
- register_value,
- bit_reg_info->parent_register));
- }
+ ACPI_DEBUG_PRINT((ACPI_DB_IO,
+ "BitReg %X, ParentReg %X, Actual %8.8X, ReturnValue %8.8X\n",
+ register_id, bit_reg_info->parent_register,
+ register_value, value));

- return_ACPI_STATUS(status);
+ *return_value = value;
+ return_ACPI_STATUS(AE_OK);
}

ACPI_EXPORT_SYMBOL(acpi_read_bit_register)
@@ -321,13 +321,16 @@ ACPI_EXPORT_SYMBOL(acpi_read_bit_register)
* SUPPORTS: Bit fields in PM1 Status, PM1 Enable, PM1 Control, and
* PM2 Control.
*
+ * Note that at this level, the fact that there may be actually two
+ * hardware registers (A and B - and B may not exist) is abstracted.
+ *
******************************************************************************/
acpi_status acpi_write_bit_register(u32 register_id, u32 value)
{
- u32 register_value = 0;
struct acpi_bit_register_info *bit_reg_info;
- acpi_status status;
acpi_cpu_flags lock_flags;
+ u32 register_value;
+ acpi_status status = AE_OK;

ACPI_FUNCTION_TRACE_U32(acpi_write_bit_register, register_id);

@@ -335,127 +338,71 @@ acpi_status acpi_write_bit_register(u32 register_id, u32 value)

bit_reg_info = acpi_hw_get_bit_register_info(register_id);
if (!bit_reg_info) {
- ACPI_ERROR((AE_INFO, "Bad ACPI HW RegisterId: %X",
- register_id));
return_ACPI_STATUS(AE_BAD_PARAMETER);
}

lock_flags = acpi_os_acquire_lock(acpi_gbl_hardware_lock);

- /* Always do a register read first so we can insert the new bits */
-
- status = acpi_hw_register_read(bit_reg_info->parent_register,
- &register_value);
- if (ACPI_FAILURE(status)) {
- goto unlock_and_exit;
- }
-
/*
- * Decode the Register ID
- * Register ID = [Register block ID] | [bit ID]
- *
- * Check bit ID to fine locate Register offset.
- * Check Mask to determine Register offset, and then read-write.
+ * At this point, we know that the parent register is one of the
+ * following: PM1 Status, PM1 Enable, PM1 Control, or PM2 Control
*/
- switch (bit_reg_info->parent_register) {
- case ACPI_REGISTER_PM1_STATUS:
-
- /*
- * Status Registers are different from the rest. Clear by
- * writing 1, and writing 0 has no effect. So, the only relevant
- * information is the single bit we're interested in, all others should
- * be written as 0 so they will be left unchanged.
- */
- value = ACPI_REGISTER_PREPARE_BITS(value,
- bit_reg_info->bit_position,
- bit_reg_info->
- access_bit_mask);
- if (value) {
- status =
- acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
- (u16) value);
- register_value = 0;
- }
- break;
-
- case ACPI_REGISTER_PM1_ENABLE:
-
- ACPI_REGISTER_INSERT_VALUE(register_value,
- bit_reg_info->bit_position,
- bit_reg_info->access_bit_mask,
- value);
-
- status = acpi_hw_register_write(ACPI_REGISTER_PM1_ENABLE,
- (u16) register_value);
- break;
-
- case ACPI_REGISTER_PM1_CONTROL:
-
+ if (bit_reg_info->parent_register != ACPI_REGISTER_PM1_STATUS) {
/*
- * Write the PM1 Control register.
- * Note that at this level, the fact that there are actually TWO
- * registers (A and B - and B may not exist) is abstracted.
+ * 1) Case for PM1 Enable, PM1 Control, and PM2 Control
+ *
+ * Perform a register read to preserve the bits that we are not
+ * interested in
*/
- ACPI_DEBUG_PRINT((ACPI_DB_IO, "PM1 control: Read %X\n",
- register_value));
-
- ACPI_REGISTER_INSERT_VALUE(register_value,
- bit_reg_info->bit_position,
- bit_reg_info->access_bit_mask,
- value);
-
- status = acpi_hw_register_write(ACPI_REGISTER_PM1_CONTROL,
- (u16) register_value);
- break;
-
- case ACPI_REGISTER_PM2_CONTROL:
-
- status = acpi_hw_register_read(ACPI_REGISTER_PM2_CONTROL,
+ status = acpi_hw_register_read(bit_reg_info->parent_register,
&register_value);
if (ACPI_FAILURE(status)) {
goto unlock_and_exit;
}

- ACPI_DEBUG_PRINT((ACPI_DB_IO,
- "PM2 control: Read %X from %8.8X%8.8X\n",
- register_value,
- ACPI_FORMAT_UINT64(acpi_gbl_FADT.
- xpm2_control_block.
- address)));
-
+ /*
+ * Insert the input bit into the value that was just read
+ * and write the register
+ */
ACPI_REGISTER_INSERT_VALUE(register_value,
bit_reg_info->bit_position,
bit_reg_info->access_bit_mask,
value);

- ACPI_DEBUG_PRINT((ACPI_DB_IO,
- "About to write %4.4X to %8.8X%8.8X\n",
- register_value,
- ACPI_FORMAT_UINT64(acpi_gbl_FADT.
- xpm2_control_block.
- address)));
+ status = acpi_hw_register_write(bit_reg_info->parent_register,
+ register_value);
+ } else {
+ /*
+ * 2) Case for PM1 Status
+ *
+ * The Status register is different from the rest. Clear an event
+ * by writing 1, writing 0 has no effect. So, the only relevant
+ * information is the single bit we're interested in, all others
+ * should be written as 0 so they will be left unchanged.
+ */
+ register_value = ACPI_REGISTER_PREPARE_BITS(value,
+ bit_reg_info->
+ bit_position,
+ bit_reg_info->
+ access_bit_mask);

- status = acpi_hw_register_write(ACPI_REGISTER_PM2_CONTROL,
- (u8) (register_value));
- break;
+ /* No need to write the register if value is all zeros */

- default:
- break;
+ if (register_value) {
+ status =
+ acpi_hw_register_write(ACPI_REGISTER_PM1_STATUS,
+ register_value);
+ }
}

- unlock_and_exit:
-
- acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
-
- /* Normalize the value that was read */
+ ACPI_DEBUG_PRINT((ACPI_DB_IO,
+ "BitReg %X, ParentReg %X, Value %8.8X, Actual %8.8X\n",
+ register_id, bit_reg_info->parent_register, value,
+ register_value));

- ACPI_DEBUG_EXEC(register_value =
- ((register_value & bit_reg_info->access_bit_mask) >>
- bit_reg_info->bit_position));
+unlock_and_exit:

- ACPI_DEBUG_PRINT((ACPI_DB_IO,
- "Set bits: %8.8X actual %8.8X register %X\n", value,
- register_value, bit_reg_info->parent_register));
+ acpi_os_release_lock(acpi_gbl_hardware_lock, lock_flags);
return_ACPI_STATUS(status);
}

--
1.6.0.6