ACPI: ACPICA 20060331

[mirror_ubuntu-zesty-kernel.git] / drivers / acpi / tables / tbutils.c

diff --git a/drivers/acpi/tables/tbutils.c b/drivers/acpi/tables/tbutils.c
index bc571592f087e784d93cca093e9a1f50472a0322..f8d28ae8811dbde2bdb6d269f95b87f480159636 100644 (file)
--- a/drivers/acpi/tables/tbutils.c
+++ b/drivers/acpi/tables/tbutils.c
@@ -96,6 +96,7 @@ acpi_status acpi_tb_is_table_installed(struct acpi_table_desc *new_table_desc)
                    (!ACPI_MEMCMP
                     (table_desc->pointer, new_table_desc->pointer,
                      new_table_desc->pointer->length))) {
+
                        /* Match: this table is already installed */
 
                        ACPI_DEBUG_PRINT((ACPI_DB_TABLES,
@@ -192,72 +193,119 @@ acpi_tb_validate_table_header(struct acpi_table_header *table_header)
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_tb_verify_table_checksum
+ * FUNCTION:    acpi_tb_sum_table
  *
- * PARAMETERS:  *table_header           - ACPI table to verify
+ * PARAMETERS:  Buffer              - Buffer to sum
+ *              Length              - Size of the buffer
  *
- * RETURN:      8 bit checksum of table
+ * RETURN:      8 bit sum of buffer
  *
- * DESCRIPTION: Does an 8 bit checksum of table and returns status.  A correct
- *              table should have a checksum of 0.
+ * DESCRIPTION: Computes an 8 bit sum of the buffer(length) and returns it.
  *
  ******************************************************************************/
 
-acpi_status
-acpi_tb_verify_table_checksum(struct acpi_table_header * table_header)
+u8 acpi_tb_sum_table(void *buffer, u32 length)
+{
+       acpi_native_uint i;
+       u8 sum = 0;
+
+       if (!buffer || !length) {
+               return (0);
+       }
+
+       for (i = 0; i < length; i++) {
+               sum = (u8) (sum + ((u8 *) buffer)[i]);
+       }
+       return (sum);
+}
+
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_tb_generate_checksum
+ *
+ * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
+ *                                    standard ACPI header)
+ *
+ * RETURN:      8 bit checksum of buffer
+ *
+ * DESCRIPTION: Computes an 8 bit checksum of the table.
+ *
+ ******************************************************************************/
+
+u8 acpi_tb_generate_checksum(struct acpi_table_header * table)
 {
        u8 checksum;
-       acpi_status status = AE_OK;
 
-       ACPI_FUNCTION_TRACE("tb_verify_table_checksum");
+       /* Sum the entire table as-is */
 
-       /* Compute the checksum on the table */
+       checksum = acpi_tb_sum_table(table, table->length);
 
-       checksum =
-           acpi_tb_generate_checksum(table_header, table_header->length);
+       /* Subtract off the existing checksum value in the table */
 
-       /* Return the appropriate exception */
+       checksum = (u8) (checksum - table->checksum);
 
-       if (checksum) {
-               ACPI_WARNING((AE_INFO,
-                             "Invalid checksum in table [%4.4s] (%02X, sum %02X is not zero)",
-                             table_header->signature,
-                             (u32) table_header->checksum, (u32) checksum));
+       /* Compute the final checksum */
 
-               status = AE_BAD_CHECKSUM;
-       }
-       return_ACPI_STATUS(status);
+       checksum = (u8) (0 - checksum);
+       return (checksum);
 }
 
 /*******************************************************************************
  *
- * FUNCTION:    acpi_tb_generate_checksum
+ * FUNCTION:    acpi_tb_set_checksum
  *
- * PARAMETERS:  Buffer              - Buffer to checksum
- *              Length              - Size of the buffer
+ * PARAMETERS:  Table               - Pointer to a valid ACPI table (with a
+ *                                    standard ACPI header)
  *
- * RETURN:      8 bit checksum of buffer
+ * RETURN:      None. Sets the table checksum field
  *
- * DESCRIPTION: Computes an 8 bit checksum of the buffer(length) and returns it.
+ * DESCRIPTION: Computes an 8 bit checksum of the table and inserts the
+ *              checksum into the table header.
  *
  ******************************************************************************/
 
-u8 acpi_tb_generate_checksum(void *buffer, u32 length)
+void acpi_tb_set_checksum(struct acpi_table_header *table)
 {
-       u8 *end_buffer;
-       u8 *rover;
-       u8 sum = 0;
 
-       if (buffer && length) {
-               /*  Buffer and Length are valid   */
+       table->checksum = acpi_tb_generate_checksum(table);
+}
 
-               end_buffer = ACPI_ADD_PTR(u8, buffer, length);
+/*******************************************************************************
+ *
+ * FUNCTION:    acpi_tb_verify_table_checksum
+ *
+ * PARAMETERS:  *table_header           - ACPI table to verify
+ *
+ * RETURN:      8 bit checksum of table
+ *
+ * DESCRIPTION: Generates an 8 bit checksum of table and returns and compares
+ *              it to the existing checksum value.
+ *
+ ******************************************************************************/
 
-               for (rover = buffer; rover < end_buffer; rover++) {
-                       sum = (u8) (sum + *rover);
-               }
+acpi_status
+acpi_tb_verify_table_checksum(struct acpi_table_header *table_header)
+{
+       u8 checksum;
+
+       ACPI_FUNCTION_TRACE("tb_verify_table_checksum");
+
+       /* Compute the checksum on the table */
+
+       checksum = acpi_tb_generate_checksum(table_header);
+
+       /* Checksum ok? */
+
+       if (checksum == table_header->checksum) {
+               return_ACPI_STATUS(AE_OK);
        }
-       return (sum);
+
+       ACPI_WARNING((AE_INFO,
+                     "Incorrect checksum in table [%4.4s] - is %2.2X, should be %2.2X",
+                     table_header->signature, table_header->checksum,
+                     checksum));
+
+       return_ACPI_STATUS(AE_BAD_CHECKSUM);
 }
 
 #ifdef ACPI_OBSOLETE_FUNCTIONS
@@ -276,7 +324,7 @@ u8 acpi_tb_generate_checksum(void *buffer, u32 length)
 
 acpi_status
 acpi_tb_handle_to_object(u16 table_id,
-                        struct acpi_table_desc ** return_table_desc)
+                        struct acpi_table_desc **return_table_desc)
 {
        u32 i;
        struct acpi_table_desc *table_desc;