[Mesa-dev] [PATCH v2] intel/decoder: Use 'DWord Length' and 'bias' fields for packet length.

[Toni Lönnberg]

Use the 'DWord Length' and 'bias' fields from the instruction definition to
parse the packet length from the command stream when possible. The hardcoded
mechanism is used whenever an instruction doesn't have this field.
---
 src/intel/common/gen_decoder.c | 30 +++++++++++++++++++++++-------
 src/intel/common/gen_decoder.h |  2 ++
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/src/intel/common/gen_decoder.c b/src/intel/common/gen_decoder.c
index 5f6e7a0b808..eaa7642fea9 100644
--- a/src/intel/common/gen_decoder.c
+++ b/src/intel/common/gen_decoder.c
@@ -163,11 +163,16 @@ create_group(struct parser_context *ctx,
    group->spec = ctx->spec;
    group->variable = false;
    group->fixed_length = fixed_length;
+   group->dword_length_field = NULL;
+   group->dw_length = 0;
+   group->bias = 1;
 
    for (int i = 0; atts[i]; i += 2) {
       char *p;
       if (strcmp(atts[i], "length") == 0) {
          group->dw_length = strtoul(atts[i + 1], &p, 0);
+      } else if (strcmp(atts[i], "bias") == 0) {
+         group->bias = strtoul(atts[i + 1], &p, 0);
       }
    }
 
@@ -288,15 +293,18 @@ create_field(struct parser_context *ctx, const char **atts)
    for (int i = 0; atts[i]; i += 2) {
       char *p;
 
-      if (strcmp(atts[i], "name") == 0)
+      if (strcmp(atts[i], "name") == 0) {
          field->name = ralloc_strdup(field, atts[i + 1]);
-      else if (strcmp(atts[i], "start") == 0)
+         if (strcmp(field->name, "DWord Length") == 0) {
+            field->parent->dword_length_field = field;
+         }
+      } else if (strcmp(atts[i], "start") == 0) {
          field->start = strtoul(atts[i + 1], &p, 0);
-      else if (strcmp(atts[i], "end") == 0) {
+      } else if (strcmp(atts[i], "end") == 0) {
          field->end = strtoul(atts[i + 1], &p, 0);
-      } else if (strcmp(atts[i], "type") == 0)
+      } else if (strcmp(atts[i], "type") == 0) {
          field->type = string_to_type(ctx, atts[i + 1]);
-      else if (strcmp(atts[i], "default") == 0 &&
+      } else if (strcmp(atts[i], "default") == 0 &&
                field->start >= 16 && field->end <= 31) {
          field->has_default = true;
          field->default_value = strtoul(atts[i + 1], &p, 0);
@@ -743,8 +751,16 @@ gen_group_find_field(struct gen_group *group, const char *name)
 int
 gen_group_get_length(struct gen_group *group, const uint32_t *p)
 {
-   if (group && group->fixed_length)
-      return group->dw_length;
+   if (group) {
+      if (group->fixed_length)
+         return group->dw_length;
+      else {
+         struct gen_field *field = group->dword_length_field;
+         if (field) {
+            return field_value(p[0], field->start, field->end) + group->bias;
+         }
+      }
+   }
 
    uint32_t h = p[0];
    uint32_t type = field_value(h, 29, 31);
diff --git a/src/intel/common/gen_decoder.h b/src/intel/common/gen_decoder.h
index a80c50b6647..4beed22d729 100644
--- a/src/intel/common/gen_decoder.h
+++ b/src/intel/common/gen_decoder.h
@@ -99,8 +99,10 @@ struct gen_group {
    char *name;
 
    struct gen_field *fields; /* linked list of fields */
+   struct gen_field *dword_length_field; /* <instruction> specific */
 
    uint32_t dw_length;
+   uint32_t bias; /* <instruction> specific */
    uint32_t group_offset, group_count;
    uint32_t group_size;
    bool variable; /* <group> specific */
-- 
2.17.1