[PATCH] make drivers/md/dm-snap.c:ksnapd static

[powerpc.git] / drivers / acpi / hardware / hwregs.c

diff --git a/drivers/acpi/hardware/hwregs.c b/drivers/acpi/hardware/hwregs.c
index ae142de..fa58c1e 100644 (file)
--- a/drivers/acpi/hardware/hwregs.c
+++ b/drivers/acpi/hardware/hwregs.c
@@ -172,9 +172,9 @@ acpi_get_sleep_type_data(u8 sleep_state, u8 * sleep_type_a, u8 * sleep_type_b)
        }
 
        /*
-        * The package must have at least two elements.  NOTE (March 2005): This
+        * The package must have at least two elements. NOTE (March 2005): This
         * goes against the current ACPI spec which defines this object as a
-        * package with one encoded DWORD element.  However, existing practice
+        * package with one encoded DWORD element. However, existing practice
         * by BIOS vendors seems to be to have 2 or more elements, at least
         * one per sleep type (A/B).
         */
@@ -255,7 +255,7 @@ struct acpi_bit_register_info *acpi_hw_get_bit_register_info(u32 register_id)
  *              return_value    - Value that was read from the register
  *              Flags           - Lock the hardware or not
  *
- * RETURN:      Status and the value read from specified Register.  Value
+ * RETURN:      Status and the value read from specified Register. Value
  *              returned is normalized to bit0 (is shifted all the way right)
  *
  * DESCRIPTION: ACPI bit_register read function.
@@ -361,8 +361,8 @@ acpi_status acpi_set_register(u32 register_id, u32 value, u32 flags)
        case ACPI_REGISTER_PM1_STATUS:
 
                /*
-                * Status Registers are different from the rest.  Clear by
-                * writing 1, and writing 0 has no effect.  So, the only relevant
+                * Status Registers are different from the rest. Clear by
+                * writing 1, and writing 0 has no effect. So, the only relevant
                 * information is the single bit we're interested in, all others should
                 * be written as 0 so they will be left unchanged.
                 */
@@ -467,14 +467,13 @@ ACPI_EXPORT_SYMBOL(acpi_set_register)
  *
  * FUNCTION:    acpi_hw_register_read
  *
- * PARAMETERS:  use_lock            - Mutex hw access
- *              register_id         - register_iD + Offset
+ * PARAMETERS:  use_lock            - Lock hardware? True/False
+ *              register_id         - ACPI Register ID
  *              return_value        - Where the register value is returned
  *
  * RETURN:      Status and the value read.
  *
- * DESCRIPTION: Acpi register read function.  Registers are read at the
- *              given offset.
+ * DESCRIPTION: Read from the specified ACPI register
  *
  ******************************************************************************/
 acpi_status
@@ -580,14 +579,26 @@ acpi_hw_register_read(u8 use_lock, u32 register_id, u32 * return_value)
  *
  * FUNCTION:    acpi_hw_register_write
  *
- * PARAMETERS:  use_lock            - Mutex hw access
- *              register_id         - register_iD + Offset
+ * PARAMETERS:  use_lock            - Lock hardware? True/False
+ *              register_id         - ACPI Register ID
  *              Value               - The value to write
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Acpi register Write function.  Registers are written at the
- *              given offset.
+ * DESCRIPTION: Write to the specified ACPI register
+ *
+ * NOTE: In accordance with the ACPI specification, this function automatically
+ * preserves the value of the following bits, meaning that these bits cannot be
+ * changed via this interface:
+ *
+ * PM1_CONTROL[0] = SCI_EN
+ * PM1_CONTROL[9]
+ * PM1_STATUS[11]
+ *
+ * ACPI References:
+ * 1) Hardware Ignored Bits: When software writes to a register with ignored
+ *      bit fields, it preserves the ignored bit fields
+ * 2) SCI_EN: OSPM always preserves this bit position
  *
  ******************************************************************************/
 
@@ -595,6 +606,7 @@ acpi_status acpi_hw_register_write(u8 use_lock, u32 register_id, u32 value)
 {
        acpi_status status;
        acpi_cpu_flags lock_flags = 0;
+       u32 read_value;
 
        ACPI_FUNCTION_TRACE(hw_register_write);
 
@@ -605,6 +617,22 @@ acpi_status acpi_hw_register_write(u8 use_lock, u32 register_id, u32 value)
        switch (register_id) {
        case ACPI_REGISTER_PM1_STATUS:  /* 16-bit access */
 
+               /* Perform a read first to preserve certain bits (per ACPI spec) */
+
+               status = acpi_hw_register_read(ACPI_MTX_DO_NOT_LOCK,
+                                              ACPI_REGISTER_PM1_STATUS,
+                                              &read_value);
+               if (ACPI_FAILURE(status)) {
+                       goto unlock_and_exit;
+               }
+
+               /* Insert the bits to be preserved */
+
+               ACPI_INSERT_BITS(value, ACPI_PM1_STATUS_PRESERVED_BITS,
+                                read_value);
+
+               /* Now we can write the data */
+
                status =
                    acpi_hw_low_level_write(16, value,
                                            &acpi_gbl_FADT->xpm1a_evt_blk);
@@ -635,6 +663,23 @@ acpi_status acpi_hw_register_write(u8 use_lock, u32 register_id, u32 value)
 
        case ACPI_REGISTER_PM1_CONTROL: /* 16-bit access */
 
+               /*
+                * Perform a read first to preserve certain bits (per ACPI spec)
+                */
+               status = acpi_hw_register_read(ACPI_MTX_DO_NOT_LOCK,
+                                              ACPI_REGISTER_PM1_CONTROL,
+                                              &read_value);
+               if (ACPI_FAILURE(status)) {
+                       goto unlock_and_exit;
+               }
+
+               /* Insert the bits to be preserved */
+
+               ACPI_INSERT_BITS(value, ACPI_PM1_CONTROL_PRESERVED_BITS,
+                                read_value);
+
+               /* Now we can write the data */
+
                status =
                    acpi_hw_low_level_write(16, value,
                                            &acpi_gbl_FADT->xpm1a_cnt_blk);
@@ -726,7 +771,7 @@ acpi_hw_low_level_read(u32 width, u32 * value, struct acpi_generic_address *reg)
                return (AE_OK);
        }
 
-       /* Get a local copy of the address.  Handles possible alignment issues */
+       /* Get a local copy of the address. Handles possible alignment issues */
 
        ACPI_MOVE_64_TO_64(&address, &reg->address);
        if (!address) {
@@ -798,7 +843,7 @@ acpi_hw_low_level_write(u32 width, u32 value, struct acpi_generic_address * reg)
                return (AE_OK);
        }
 
-       /* Get a local copy of the address.  Handles possible alignment issues */
+       /* Get a local copy of the address. Handles possible alignment issues */
 
        ACPI_MOVE_64_TO_64(&address, &reg->address);
        if (!address) {