ACPICA: Update buffer-to-string conversions

Add "0x" prefix for hex values.
Provides compatibility with other ACPI implementations.

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Erik Schmauss <erik.schmauss@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/acpica/exconvrt.c b/drivers/acpi/acpica/exconvrt.c
index 98de48481776b13315203634a0d7694d36afc156..1a70b80cc40619b3d47f3fd8a91398b14571db25 100644 (file)
--- a/drivers/acpi/acpica/exconvrt.c
+++ b/drivers/acpi/acpica/exconvrt.c
@@ -323,7 +323,7 @@ acpi_ex_convert_to_ascii(u64 integer, u16 base, u8 *string, u8 data_width)
 
                /* hex_length: 2 ascii hex chars per data byte */
 
-               hex_length = ACPI_MUL_2(data_width);
+               hex_length = (data_width * 2);
                for (i = 0, j = (hex_length - 1); i < hex_length; i++, j--) {
 
                        /* Get one hex digit, most significant digits first */
@@ -364,7 +364,8 @@ acpi_ex_convert_to_ascii(u64 integer, u16 base, u8 *string, u8 data_width)
  *
  * RETURN:      Status
  *
- * DESCRIPTION: Convert an ACPI Object to a string
+ * DESCRIPTION: Convert an ACPI Object to a string. Supports both implicit
+ *              and explicit conversions and related rules.
  *
  ******************************************************************************/
 
@@ -393,9 +394,11 @@ acpi_ex_convert_to_string(union acpi_operand_object * obj_desc,
 
                switch (type) {
                case ACPI_EXPLICIT_CONVERT_DECIMAL:
-
-                       /* Make room for maximum decimal number */
-
+                       /*
+                        * From to_decimal_string, integer source.
+                        *
+                        * Make room for the maximum decimal number size
+                        */
                        string_length = ACPI_MAX_DECIMAL_DIGITS;
                        base = 10;
                        break;
@@ -440,8 +443,10 @@ acpi_ex_convert_to_string(union acpi_operand_object * obj_desc,
                switch (type) {
                case ACPI_EXPLICIT_CONVERT_DECIMAL:     /* Used by to_decimal_string */
                        /*
-                        * From ACPI: "If Data is a buffer, it is converted to a string of
-                        * decimal values separated by commas."
+                        * Explicit conversion from the to_decimal_string ASL operator.
+                        *
+                        * From ACPI: "If the input is a buffer, it is converted to a
+                        * a string of decimal values separated by commas."
                         */
                        base = 10;
 
@@ -462,20 +467,29 @@ acpi_ex_convert_to_string(union acpi_operand_object * obj_desc,
 
                case ACPI_IMPLICIT_CONVERT_HEX:
                        /*
+                        * Implicit buffer-to-string conversion
+                        *
                         * From the ACPI spec:
-                        *"The entire contents of the buffer are converted to a string of
+                        * "The entire contents of the buffer are converted to a string of
                         * two-character hexadecimal numbers, each separated by a space."
+                        *
+                        * Each hex number is prefixed with 0x (11/2018)
                         */
                        separator = ' ';
-                       string_length = (obj_desc->buffer.length * 3);
+                       string_length = (obj_desc->buffer.length * 5);
                        break;
 
-               case ACPI_EXPLICIT_CONVERT_HEX: /* Used by to_hex_string */
+               case ACPI_EXPLICIT_CONVERT_HEX:
                        /*
+                        * Explicit conversion from the to_hex_string ASL operator.
+                        *
                         * From ACPI: "If Data is a buffer, it is converted to a string of
                         * hexadecimal values separated by commas."
+                        *
+                        * Each hex number is prefixed with 0x (11/2018)
                         */
-                       string_length = (obj_desc->buffer.length * 3);
+                       separator = ',';
+                       string_length = (obj_desc->buffer.length * 5);
                        break;
 
                default:
@@ -504,10 +518,21 @@ acpi_ex_convert_to_string(union acpi_operand_object * obj_desc,
                 * (separated by commas or spaces)
                 */
                for (i = 0; i < obj_desc->buffer.length; i++) {
+                       if (base == 16) {
+
+                               /* Emit 0x prefix for explict/implicit hex conversion */
+
+                               *new_buf++ = '0';
+                               *new_buf++ = 'x';
+                       }
+
                        new_buf += acpi_ex_convert_to_ascii((u64) obj_desc->
                                                            buffer.pointer[i],
                                                            base, new_buf, 1);
-                       *new_buf++ = separator; /* each separated by a comma or space */
+
+                       /* Each digit is separated by either a comma or space */
+
+                       *new_buf++ = separator;
                }
 
                /*