ACPI: fix FADT parsing

The (1.0 inherited) separate length fields in the FADT are byte granular.
Further, PM1a/b may have distinct lengths (if using the v2 fields was
okay) and may live in distinct address spaces.  acpi_tb_convert_fadt()
should account for all of these conditions.

Apart from these changes I'm puzzled by the fact that, not just for
acpi_gbl_xpm1{a,b}_enable, acpi_hw_low_level_{read,write}() get an
explicit size passed rather than using the size found in the passed GAS.
What happens on a platform that defines PM1{a,b} wider than 16 bits?  Of
course, acpi_hw_low_level_{read,write}() at present are entirely
un-prepared to deal with sizes other than 8, 16, or 32, not to speak of a
non-zero bit_offset or access_width...

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 25 insertions, 7 deletions

diff --git a/drivers/acpi/tables/tbfadt.c b/drivers/acpi/tables/tbfadt.c
index a4a41ba2484b..2c7885e7ffba 100644
--- a/drivers/acpi/tables/tbfadt.c
+++ b/drivers/acpi/tables/tbfadt.c
@@ -50,7 +50,7 @@ ACPI_MODULE_NAME("tbfadt")
 /* Local prototypes */
 static void inline
 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
-                             u8 bit_width, u64 address);
+                             u8 byte_width, u64 address);
 
 static void acpi_tb_convert_fadt(void);
 
@@ -111,7 +111,7 @@ static struct acpi_fadt_info fadt_info_table[] = {
  * FUNCTION:    acpi_tb_init_generic_address
  *
  * PARAMETERS:  generic_address     - GAS struct to be initialized
- *              bit_width           - Width of this register
+ *              byte_width          - Width of this register
  *              Address             - Address of the register
  *
  * RETURN:      None
@@ -124,7 +124,7 @@ static struct acpi_fadt_info fadt_info_table[] = {
 
 static void inline
 acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
-                             u8 bit_width, u64 address)
+                             u8 byte_width, u64 address)
 {
 
         /*
@@ -136,7 +136,7 @@ acpi_tb_init_generic_address(struct acpi_generic_address *generic_address,
         /* All other fields are byte-wide */
 
         generic_address->space_id = ACPI_ADR_SPACE_SYSTEM_IO;
-        generic_address->bit_width = bit_width;
+        generic_address->bit_width = byte_width << 3;
         generic_address->bit_offset = 0;
         generic_address->access_width = 0;
 }
@@ -342,9 +342,20 @@ static void acpi_tb_convert_fadt(void)
          * useful to calculate them once, here.
          *
          * The PM event blocks are split into two register blocks, first is the
-         * PM Status Register block, followed immediately by the PM Enable Register
-         * block. Each is of length (pm1_event_length/2)
+         * PM Status Register block, followed immediately by the PM Enable
+         * Register block. Each is of length (xpm1x_event_block.bit_width/2).
+         *
+         * On various systems the v2 fields (and particularly the bit widths)
+         * cannot be relied upon, though. Hence resort to using the v1 length
+         * here (and warn about the inconsistency).
          */
+        if (acpi_gbl_FADT.xpm1a_event_block.bit_width
+            != acpi_gbl_FADT.pm1_event_length * 8)
+                printk(KERN_WARNING "FADT: "
+                       "X_PM1a_EVT_BLK.bit_width (%u) does not match"
+                       " PM1_EVT_LEN (%u)\n",
+                       acpi_gbl_FADT.xpm1a_event_block.bit_width,
+                       acpi_gbl_FADT.pm1_event_length);
         pm1_register_length = (u8) ACPI_DIV_2(acpi_gbl_FADT.pm1_event_length);
 
         /* The PM1A register block is required */
@@ -360,13 +371,20 @@ static void acpi_tb_convert_fadt(void)
         /* The PM1B register block is optional, ignore if not present */
 
         if (acpi_gbl_FADT.xpm1b_event_block.address) {
+                if (acpi_gbl_FADT.xpm1b_event_block.bit_width
+                    != acpi_gbl_FADT.pm1_event_length * 8)
+                        printk(KERN_WARNING "FADT: "
+                               "X_PM1b_EVT_BLK.bit_width (%u) does not match"
+                               " PM1_EVT_LEN (%u)\n",
+                               acpi_gbl_FADT.xpm1b_event_block.bit_width,
+                               acpi_gbl_FADT.pm1_event_length);
                 acpi_tb_init_generic_address(&acpi_gbl_xpm1b_enable,
                                              pm1_register_length,
                                              (acpi_gbl_FADT.xpm1b_event_block.
                                               address + pm1_register_length));
                 /* Don't forget to copy space_id of the GAS */
                 acpi_gbl_xpm1b_enable.space_id =
-                    acpi_gbl_FADT.xpm1a_event_block.space_id;
+                    acpi_gbl_FADT.xpm1b_event_block.space_id;
 
         }
 }