ACPICA: ACPI 2.0, Hardware: Add access_width/bit_offset support in acpi_hw_read()

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>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/acpica/hwregs.c b/drivers/acpi/acpica/hwregs.c
index 892e677f524f87f3c78fe494a4c0230e7137b496..6eee012cfd8f41fb71abfd90b14a4c57d1f475a2 100644 (file)
--- 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);