acpi_read(), acpi_write(), acpi_hw_read(), and acpi_hw_write() currently
ignore the GAS bit_offset field (but they do warn if it is non-zero).
APEI tables are starting to use non-zero bit_offsets. APEI uses
special-purpose apei_exec_read_register() and apei_exec_write_register()
interfaces that apply the bit_offset.
This patch adds bit_offset support to the generic interfaces, which is
one small step toward using them instead of the special-purpose APEI ones.
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---
drivers/acpi/acpica/hwregs.c | 32 ++++++++++++++++++++------------
drivers/acpi/acpica/hwxface.c | 8 +++++---
2 files changed, 25 insertions(+), 15 deletions(-)
diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index cc70f3f..2b50800 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -82,6 +82,7 @@ acpi_status
acpi_hw_validate_register(struct acpi_generic_address *reg,
u8 max_bit_width, u64 *address)
{
+ static u8 width[] = {64, 8, 16, 32, 64};
/* Must have a valid pointer to a GAS structure */
@@ -119,12 +120,14 @@ acpi_hw_validate_register(struct acpi_generic_address *reg,
return (AE_SUPPORT);
}
- /* Validate the bit_offset. Just a warning for now. */
+ /* Validate the bit_offset */
- if (reg->bit_offset != 0) {
- ACPI_WARNING((AE_INFO,
- "Unsupported register bit offset: 0x%X",
- reg->bit_offset));
+ if (reg->bit_offset > width[reg->access_width] - 1) {
+ ACPI_ERROR((AE_INFO,
+ "Unsupported register bit offset: 0x%X access size: 0x%X (%d bits)",
+ reg->bit_offset, reg->access_width,
+ width[reg->access_width]));
+ return (AE_BAD_ADDRESS);
}
return (AE_OK);
@@ -146,14 +149,15 @@ acpi_hw_validate_register(struct acpi_generic_address *reg,
* 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.
+ * access_width is currently ignored, as there has
+ * not been a need to implement it.
*
******************************************************************************/
-acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
+acpi_status acpi_hw_read(u32 *return_value, struct acpi_generic_address *reg)
{
u64 address;
+ u32 value;
acpi_status status;
ACPI_FUNCTION_NAME(hw_read);
@@ -167,7 +171,7 @@ acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
/* Initialize entire 32-bit return value to zero */
- *value = 0;
+ *return_value = 0;
/*
* Two address spaces supported: Memory or IO. PCI_Config is
@@ -175,16 +179,18 @@ acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
*/
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
status = acpi_os_read_memory((acpi_physical_address)
- address, value, reg->bit_width);
+ 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);
+ address, &value, reg->bit_width);
}
+ *return_value = value >> reg->bit_offset;
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),
+ *return_value, reg->bit_width,
+ ACPI_FORMAT_UINT64(address),
acpi_ut_get_region_name(reg->space_id)));
return (status);
@@ -219,6 +225,8 @@ acpi_status acpi_hw_write(u32 value, struct acpi_generic_address *reg)
return (status);
}
+ value = value << reg->bit_offset;
+
/*
* Two address spaces supported: Memory or IO. PCI_Config is
* not supported here because the GAS structure is insufficient
diff --git a/drivers/acpi/acpica/hwxface.c b/drivers/acpi/acpica/hwxface.c
index 12b5c57..a0526fe 100644
--- a/drivers/acpi/acpica/hwxface.c
+++ b/drivers/acpi/acpica/hwxface.c
@@ -114,8 +114,8 @@ ACPI_EXPORT_SYMBOL(acpi_reset)
* 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.
+ * access_width is currently ignored, as there has
+ * not been a need to implement it.
*
******************************************************************************/
acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
@@ -195,7 +195,7 @@ acpi_status acpi_read(u64 *return_value, struct acpi_generic_address *reg)
}
}
- *return_value = complete_value;
+ *return_value = complete_value >> reg->bit_offset;
ACPI_DEBUG_PRINT((ACPI_DB_IO,
"Read: %8.8X%8.8X width %2d from %8.8X%8.8X (%s)\n",
ACPI_FORMAT_UINT64(*return_value), reg->bit_width,
@@ -239,6 +239,8 @@ acpi_status acpi_write(u64 value, struct acpi_generic_address *reg)
width = 32; /* Break into two 32-bit transfers */
}
+ value = value << reg->bit_offset;
+
/*
* Two address spaces supported: Memory or IO. PCI_Config is
* not supported here because the GAS structure is insufficient
--
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