ACPICA: Revert "Revert "Enable multi-byte EC transfers

This reverts commit f23b9c7(http://git.moblin.org/cgit.cgi/acpica/commit/?id=f23b9c7)
The problem with this change was determined to be a problem with
the FreeBSD host OSL (OS services layer), not with this patch
itself. Therefore, re-introducing this change into the main ACPICA
code. See ACPICA bugzilla 863.

http://www.acpica.org/bugzilla/show_bug.cgi?id=863

Signed-off-by: Bob Moore <robert.moore@intel.com>
Signed-off-by: Lin Ming <ming.m.lin@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

3 files changed, 73 insertions, 49 deletions

diff --git a/drivers/acpi/acpica/acobject.h b/drivers/acpi/acpica/acobject.h
index 54857fa87aaf..bdbfaf22bd14 100644
--- a/drivers/acpi/acpica/acobject.h
+++ b/drivers/acpi/acpica/acobject.h
@@ -248,7 +248,7 @@ ACPI_OBJECT_COMMON_HEADER ACPI_COMMON_NOTIFY_INFO};
         u32                             base_byte_offset;   /* Byte offset within containing object */\
         u32                             value;              /* Value to store into the Bank or Index register */\
         u8                              start_field_bit_offset;/* Bit offset within first field datum (0-63) */\
-        u8                              access_bit_width;       /* Read/Write size in bits (8-64) */
+
 
 struct acpi_object_field_common {       /* COMMON FIELD (for BUFFER, REGION, BANK, and INDEX fields) */
         ACPI_OBJECT_COMMON_HEADER ACPI_COMMON_FIELD_INFO union acpi_operand_object *region_obj; /* Parent Operation Region object (REGION/BANK fields only) */
diff --git a/drivers/acpi/acpica/exfldio.c b/drivers/acpi/acpica/exfldio.c
index 047217303a4b..38293fd3e088 100644
--- a/drivers/acpi/acpica/exfldio.c
+++ b/drivers/acpi/acpica/exfldio.c
@@ -119,8 +119,8 @@ acpi_ex_setup_region(union acpi_operand_object *obj_desc,
         }
 
         /*
-         * Exit now for SMBus or IPMI address space, it has a non-linear address space
-         * and the request cannot be directly validated
+         * Exit now for SMBus or IPMI address space, it has a non-linear
+         * address space and the request cannot be directly validated
          */
         if (rgn_desc->region.space_id == ACPI_ADR_SPACE_SMBUS ||
             rgn_desc->region.space_id == ACPI_ADR_SPACE_IPMI) {
@@ -147,8 +147,7 @@ acpi_ex_setup_region(union acpi_operand_object *obj_desc,
          * (Region length is specified in bytes)
          */
         if (rgn_desc->region.length <
-            (obj_desc->common_field.base_byte_offset +
-             field_datum_byte_offset +
+            (obj_desc->common_field.base_byte_offset + field_datum_byte_offset +
              obj_desc->common_field.access_byte_width)) {
                 if (acpi_gbl_enable_interpreter_slack) {
                         /*
@@ -680,6 +679,7 @@ acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
         u32 buffer_tail_bits;
         u32 datum_count;
         u32 field_datum_count;
+        u32 access_bit_width;
         u32 i;
 
         ACPI_FUNCTION_TRACE(ex_extract_from_field);
@@ -694,16 +694,36 @@ acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
 
                 return_ACPI_STATUS(AE_BUFFER_OVERFLOW);
         }
+
         ACPI_MEMSET(buffer, 0, buffer_length);
+        access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
+
+        /* Handle the simple case here */
+
+        if ((obj_desc->common_field.start_field_bit_offset == 0) &&
+            (obj_desc->common_field.bit_length == access_bit_width)) {
+                status = acpi_ex_field_datum_io(obj_desc, 0, buffer, ACPI_READ);
+                return_ACPI_STATUS(status);
+        }
+
+/* TBD: Move to common setup code */
+
+        /* Field algorithm is limited to sizeof(u64), truncate if needed */
+
+        if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
+                obj_desc->common_field.access_byte_width = sizeof(u64);
+                access_bit_width = sizeof(u64) * 8;
+        }
 
         /* Compute the number of datums (access width data items) */
 
-        datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
-                                       obj_desc->common_field.access_bit_width);
+        datum_count =
+            ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
+                             access_bit_width);
+
         field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
                                              obj_desc->common_field.
                                              start_field_bit_offset,
-                                             obj_desc->common_field.
                                              access_bit_width);
 
         /* Priming read from the field */
@@ -738,12 +758,11 @@ acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
                  * This avoids the differences in behavior between different compilers
                  * concerning shift values larger than the target data width.
                  */
-                if ((obj_desc->common_field.access_bit_width -
-                     obj_desc->common_field.start_field_bit_offset) <
+                if (access_bit_width -
+                    obj_desc->common_field.start_field_bit_offset <
                     ACPI_INTEGER_BIT_SIZE) {
                         merged_datum |=
-                            raw_datum << (obj_desc->common_field.
-                                          access_bit_width -
+                            raw_datum << (access_bit_width -
                                           obj_desc->common_field.
                                           start_field_bit_offset);
                 }
@@ -765,8 +784,7 @@ acpi_ex_extract_from_field(union acpi_operand_object *obj_desc,
 
         /* Mask off any extra bits in the last datum */
 
-        buffer_tail_bits = obj_desc->common_field.bit_length %
-            obj_desc->common_field.access_bit_width;
+        buffer_tail_bits = obj_desc->common_field.bit_length % access_bit_width;
         if (buffer_tail_bits) {
                 merged_datum &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
         }
@@ -798,6 +816,7 @@ acpi_status
 acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
                           void *buffer, u32 buffer_length)
 {
+        void *new_buffer;
         acpi_status status;
         u64 mask;
         u64 width_mask;
@@ -808,9 +827,9 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
         u32 buffer_tail_bits;
         u32 datum_count;
         u32 field_datum_count;
-        u32 i;
+        u32 access_bit_width;
         u32 required_length;
-        void *new_buffer;
+        u32 i;
 
         ACPI_FUNCTION_TRACE(ex_insert_into_field);
 
@@ -844,17 +863,24 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
                 buffer_length = required_length;
         }
 
+/* TBD: Move to common setup code */
+
+        /* Algo is limited to sizeof(u64), so cut the access_byte_width */
+        if (obj_desc->common_field.access_byte_width > sizeof(u64)) {
+                obj_desc->common_field.access_byte_width = sizeof(u64);
+        }
+
+        access_bit_width = ACPI_MUL_8(obj_desc->common_field.access_byte_width);
+
         /*
          * Create the bitmasks used for bit insertion.
          * Note: This if/else is used to bypass compiler differences with the
          * shift operator
          */
-        if (obj_desc->common_field.access_bit_width == ACPI_INTEGER_BIT_SIZE) {
+        if (access_bit_width == ACPI_INTEGER_BIT_SIZE) {
                 width_mask = ACPI_UINT64_MAX;
         } else {
-                width_mask =
-                    ACPI_MASK_BITS_ABOVE(obj_desc->common_field.
-                                         access_bit_width);
+                width_mask = ACPI_MASK_BITS_ABOVE(access_bit_width);
         }
 
         mask = width_mask &
@@ -863,12 +889,11 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
         /* Compute the number of datums (access width data items) */
 
         datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length,
-                                       obj_desc->common_field.access_bit_width);
+                                       access_bit_width);
 
         field_datum_count = ACPI_ROUND_UP_TO(obj_desc->common_field.bit_length +
                                              obj_desc->common_field.
                                              start_field_bit_offset,
-                                             obj_desc->common_field.
                                              access_bit_width);
 
         /* Get initial Datum from the input buffer */
@@ -905,12 +930,11 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
                  * This avoids the differences in behavior between different compilers
                  * concerning shift values larger than the target data width.
                  */
-                if ((obj_desc->common_field.access_bit_width -
+                if ((access_bit_width -
                      obj_desc->common_field.start_field_bit_offset) <
                     ACPI_INTEGER_BIT_SIZE) {
                         merged_datum =
-                            raw_datum >> (obj_desc->common_field.
-                                          access_bit_width -
+                            raw_datum >> (access_bit_width -
                                           obj_desc->common_field.
                                           start_field_bit_offset);
                 } else {
@@ -929,6 +953,7 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
                 ACPI_MEMCPY(&raw_datum, ((char *)buffer) + buffer_offset,
                             ACPI_MIN(obj_desc->common_field.access_byte_width,
                                      buffer_length - buffer_offset));
+
                 merged_datum |=
                     raw_datum << obj_desc->common_field.start_field_bit_offset;
         }
@@ -937,7 +962,7 @@ acpi_ex_insert_into_field(union acpi_operand_object *obj_desc,
 
         buffer_tail_bits = (obj_desc->common_field.bit_length +
                             obj_desc->common_field.start_field_bit_offset) %
-            obj_desc->common_field.access_bit_width;
+            access_bit_width;
         if (buffer_tail_bits) {
                 mask &= ACPI_MASK_BITS_ABOVE(buffer_tail_bits);
         }
diff --git a/drivers/acpi/acpica/exprep.c b/drivers/acpi/acpica/exprep.c
index 98a331d2249b..7aae29f73d3f 100644
--- a/drivers/acpi/acpica/exprep.c
+++ b/drivers/acpi/acpica/exprep.c
@@ -355,12 +355,10 @@ acpi_ex_prep_common_field_object(union acpi_operand_object *obj_desc,
                 return_ACPI_STATUS(AE_AML_OPERAND_VALUE);
         }
 
-        /* Setup width (access granularity) fields */
+        /* Setup width (access granularity) fields (values are: 1, 2, 4, 8) */
 
         obj_desc->common_field.access_byte_width = (u8)
-            ACPI_DIV_8(access_bit_width);       /* 1,  2,  4,  8 */
-
-        obj_desc->common_field.access_bit_width = (u8) access_bit_width;
+            ACPI_DIV_8(access_bit_width);
 
         /*
          * base_byte_offset is the address of the start of the field within the
@@ -405,8 +403,9 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
 {
         union acpi_operand_object *obj_desc;
         union acpi_operand_object *second_desc = NULL;
-        u32 type;
         acpi_status status;
+        u32 access_byte_width;
+        u32 type;
 
         ACPI_FUNCTION_TRACE(ex_prep_field_value);
 
@@ -421,8 +420,8 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
                 type = acpi_ns_get_type(info->region_node);
                 if (type != ACPI_TYPE_REGION) {
                         ACPI_ERROR((AE_INFO,
-                                    "Needed Region, found type 0x%X (%s)",
-                                    type, acpi_ut_get_type_name(type)));
+                                    "Needed Region, found type 0x%X (%s)", type,
+                                    acpi_ut_get_type_name(type)));
 
                         return_ACPI_STATUS(AE_AML_OPERAND_TYPE);
                 }
@@ -438,7 +437,8 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
         /* Initialize areas of the object that are common to all fields */
 
         obj_desc->common_field.node = info->field_node;
-        status = acpi_ex_prep_common_field_object(obj_desc, info->field_flags,
+        status = acpi_ex_prep_common_field_object(obj_desc,
+                                                  info->field_flags,
                                                   info->attribute,
                                                   info->field_bit_position,
                                                   info->field_bit_length);
@@ -455,26 +455,25 @@ acpi_status acpi_ex_prep_field_value(struct acpi_create_field_info *info)
                 obj_desc->field.region_obj =
                     acpi_ns_get_attached_object(info->region_node);
 
-                /* An additional reference for the container */
+                /* Allow full data read from EC address space */
 
-                acpi_ut_add_reference(obj_desc->field.region_obj);
+                if ((obj_desc->field.region_obj->region.space_id ==
+                     ACPI_ADR_SPACE_EC)
+                    && (obj_desc->common_field.bit_length > 8)) {
+                        access_byte_width =
+                            ACPI_ROUND_BITS_UP_TO_BYTES(obj_desc->common_field.
+                                                        bit_length);
+
+                        /* Maximum byte width supported is 255 */
 
-                /* allow full data read from EC address space */
-                if (obj_desc->field.region_obj->region.space_id ==
-                        ACPI_ADR_SPACE_EC) {
-                        if (obj_desc->common_field.bit_length > 8) {
-                                unsigned width =
-                                        ACPI_ROUND_BITS_UP_TO_BYTES(
-                                        obj_desc->common_field.bit_length);
-                                // access_bit_width is u8, don't overflow it
-                                if (width > 8)
-                                        width = 8;
+                        if (access_byte_width < 256) {
                                 obj_desc->common_field.access_byte_width =
-                                                        width;
-                                obj_desc->common_field.access_bit_width =
-                                                        8 * width;
+                                    (u8)access_byte_width;
                         }
                 }
+                /* An additional reference for the container */
+
+                acpi_ut_add_reference(obj_desc->field.region_obj);
 
                 ACPI_DEBUG_PRINT((ACPI_DB_BFIELD,
                                   "RegionField: BitOff %X, Off %X, Gran %X, Region %p\n",