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>

diff --git a/drivers/acpi/tables/tbfadt.c b/drivers/acpi/tables/tbfadt.c
index a4a41ba..2c7885e 100644 (file)
--- 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;
 
        }
 }