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Subject[PATCH v2 10/13] ACPICA: ACPI 2.0, Hardware: Add access_width/bit_offset support in acpi_hw_read()
Date
ACPICA commit 96ece052d4d073aae4f935f0ff0746646aea1174
ACPICA commit 3d8583a054e410f2ea4d73b48986facad9cfc0d4

This patch adds access_width/bit_offset support in acpi_hw_read().
This also enables GAS definition where bit_width is not a power of
two. Lv Zheng.

Link: https://github.com/acpica/acpica/commit/96ece052
Link: https://github.com/acpica/acpica/commit/3d8583a0
Link: https://bugs.acpica.org/show_bug.cgi?id=1240
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Bob Moore <robert.moore@intel.com>
---
drivers/acpi/acpica/hwregs.c | 75 ++++++++++++++++++++++++++++++++++--------
1 file changed, 62 insertions(+), 13 deletions(-)

diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 892e677..6eee012 100644
--- a/drivers/acpi/acpica/hwregs.c
+++ b/drivers/acpi/acpica/hwregs.c
@@ -195,17 +195,19 @@ acpi_hw_validate_register(struct acpi_generic_address *reg,
* 64-bit values is not needed.
*
* 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.
*
******************************************************************************/

acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
{
u64 address;
+ u8 access_width;
+ u32 bit_width;
+ u8 bit_offset;
u64 value64;
+ u32 value32;
+ u8 index;
acpi_status status;

ACPI_FUNCTION_NAME(hw_read);
@@ -217,28 +219,75 @@ acpi_status acpi_hw_read(u32 *value, struct acpi_generic_address *reg)
return (status);
}

- /* Initialize entire 32-bit return value to zero */
-
+ /*
+ * Initialize entire 32-bit return value to zero, convert access_width
+ * into number of bits based
+ */
*value = 0;
+ access_width = acpi_hw_get_access_bit_width(reg, 32);
+ bit_width = reg->bit_offset + reg->bit_width;
+ bit_offset = reg->bit_offset;

/*
* Two address spaces supported: Memory or IO. PCI_Config is
* not supported here because the GAS structure is insufficient
*/
- if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
- status = acpi_os_read_memory((acpi_physical_address)
- address, &value64, reg->bit_width);
+ index = 0;
+ while (bit_width) {
+ if (bit_offset >= access_width) {
+ value32 = 0;
+ bit_offset -= access_width;
+ } else {
+ if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+ status =
+ acpi_os_read_memory((acpi_physical_address)
+ address +
+ index *
+ ACPI_DIV_8
+ (access_width),
+ &value64, access_width);
+ value32 = (u32)value64;
+ } else { /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+
+ status = acpi_hw_read_port((acpi_io_address)
+ address +
+ index *
+ ACPI_DIV_8
+ (access_width),
+ &value32,
+ access_width);
+ }

- *value = (u32)value64;
- } else { /* ACPI_ADR_SPACE_SYSTEM_IO, validated earlier */
+ /*
+ * Use offset style bit masks because:
+ * bit_offset < access_width/bit_width < access_width, and
+ * access_width is ensured to be less than 32-bits by
+ * acpi_hw_validate_register().
+ */
+ if (bit_offset) {
+ value32 &= ACPI_MASK_BITS_BELOW(bit_offset);
+ bit_offset = 0;
+ }
+ if (bit_width < access_width) {
+ value32 &= ACPI_MASK_BITS_ABOVE(bit_width);
+ }
+ }
+
+ /*
+ * Use offset style bit writes because "Index * AccessWidth" is
+ * ensured to be less than 32-bits by acpi_hw_validate_register().
+ */
+ ACPI_SET_BITS(value, index * access_width,
+ ACPI_MASK_BITS_ABOVE_32(access_width), value32);

- status = acpi_hw_read_port((acpi_io_address)
- address, value, reg->bit_width);
+ bit_width -=
+ bit_width > access_width ? access_width : bit_width;
+ index++;
}

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),
+ *value, access_width, ACPI_FORMAT_UINT64(address),
acpi_ut_get_region_name(reg->space_id)));

return (status);
--
1.7.10
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