i965: add a kernel_features bitfield to intel screen

We can use this to track various features that may or may not be supported
by the hw / kernel. Currently, we usually do this by checking the generation
and supported command parser versions in various places thoughtout the driver
code. With this patch, we centralize all these checks in just once place at
screen creation time, then we just query the bitfield wherever we need to
check if a particular feature is supported.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index 3f3da7d..032b5ec 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -468,7 +468,7 @@
 
    functions->NewTransformFeedback = brw_new_transform_feedback;
    functions->DeleteTransformFeedback = brw_delete_transform_feedback;
-   if (brw->screen->has_mi_math_and_lrr) {
+   if (can_do_mi_math_and_lrr(brw->screen)) {
       functions->BeginTransformFeedback = hsw_begin_transform_feedback;
       functions->EndTransformFeedback = hsw_end_transform_feedback;
       functions->PauseTransformFeedback = hsw_pause_transform_feedback;
@@ -608,7 +608,7 @@
       BRW_MAX_SOL_BINDINGS / BRW_MAX_SOL_BUFFERS;
 
    ctx->Const.AlwaysUseGetTransformFeedbackVertexCount =
-      !brw->screen->has_mi_math_and_lrr;
+      !can_do_mi_math_and_lrr(brw->screen);
 
    int max_samples;
    const int *msaa_modes = intel_supported_msaa_modes(brw->screen);
diff --git a/src/mesa/drivers/dri/i965/gen7_l3_state.c b/src/mesa/drivers/dri/i965/gen7_l3_state.c
index 85f8e46..dce39c3 100644
--- a/src/mesa/drivers/dri/i965/gen7_l3_state.c
+++ b/src/mesa/drivers/dri/i965/gen7_l3_state.c
@@ -175,7 +175,7 @@
 
       ADVANCE_BATCH();
 
-      if (brw->is_haswell && brw->screen->cmd_parser_version >= 4) {
+      if (can_do_hsw_l3_atomics(brw->screen)) {
          /* Enable L3 atomics on HSW if we have a DC partition, otherwise keep
           * them disabled to avoid crashing the system hard.
           */
diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
index aa89380..22651de 100644
--- a/src/mesa/drivers/dri/i965/intel_extensions.c
+++ b/src/mesa/drivers/dri/i965/intel_extensions.c
@@ -227,14 +227,14 @@
          ctx->Extensions.ARB_transform_feedback3 = true;
          ctx->Extensions.ARB_transform_feedback_instanced = true;
 
-         if ((brw->gen >= 8 || brw->screen->cmd_parser_version >= 5) &&
+         if (can_do_compute_dispatch(brw->screen) &&
              ctx->Const.MaxComputeWorkGroupSize[0] >= 1024) {
             ctx->Extensions.ARB_compute_shader = true;
             ctx->Extensions.ARB_ES3_1_compatibility =
                brw->gen >= 8 || brw->is_haswell;
          }
 
-         if (brw->screen->cmd_parser_version >= 2)
+         if (can_do_predicate_writes(brw->screen))
             brw->predicate.supported = true;
       }
    }
@@ -248,7 +248,7 @@
       ctx->Extensions.ARB_robust_buffer_access_behavior = true;
    }
 
-   if (brw->screen->has_mi_math_and_lrr) {
+   if (can_do_mi_math_and_lrr(brw->screen)) {
       ctx->Extensions.ARB_query_buffer_object = true;
    }
 
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index c3fd6f6..c79268f 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -1735,7 +1735,7 @@
    }
 
    if (intel_detect_pipelined_so(screen))
-      screen->hw_has_pipelined_register |= HW_HAS_PIPELINED_SOL_OFFSET;
+      screen->kernel_features |= KERNEL_ALLOWS_SOL_OFFSET_WRITES;
 
    const char *force_msaa = getenv("INTEL_FORCE_MSAA");
    if (force_msaa) {
@@ -1773,13 +1773,29 @@
       screen->cmd_parser_version = 0;
    }
 
+   if (screen->cmd_parser_version >= 2)
+      screen->kernel_features |= KERNEL_ALLOWS_PREDICATE_WRITES;
+
+   /* Haswell requires command parser version 4 in order to have L3
+    * atomic scratch1 and chicken3 bits
+    */
+   if (screen->devinfo.is_haswell && screen->cmd_parser_version >= 4) {
+      screen->kernel_features |=
+         KERNEL_ALLOWS_HSW_SCRATCH1_AND_ROW_CHICKEN3;
+   }
+
    /* Haswell requires command parser version 6 in order to write to the
     * MI_MATH GPR registers, and version 7 in order to use
     * MI_LOAD_REGISTER_REG (which all users of MI_MATH use).
     */
-   screen->has_mi_math_and_lrr = screen->devinfo.gen >= 8 ||
-                                      (screen->devinfo.is_haswell &&
-                                       screen->cmd_parser_version >= 7);
+   if (screen->devinfo.gen >= 8 ||
+       (screen->devinfo.is_haswell && screen->cmd_parser_version >= 7)) {
+      screen->kernel_features |= KERNEL_ALLOWS_MI_MATH_AND_LRR;
+   }
+
+   /* Gen7 needs at least command parser version 5 to support compute */
+   if (screen->devinfo.gen >= 8 || screen->cmd_parser_version >= 5)
+      screen->kernel_features |= KERNEL_ALLOWS_COMPUTE_DISPATCH;
 
    dri_screen->extensions = !screen->has_context_reset_notification
       ? screenExtensions : intelRobustScreenExtensions;
diff --git a/src/mesa/drivers/dri/i965/intel_screen.h b/src/mesa/drivers/dri/i965/intel_screen.h
index 2cbff14..890dd90 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.h
+++ b/src/mesa/drivers/dri/i965/intel_screen.h
@@ -58,23 +58,20 @@
    bool has_resource_streamer;
 
    /**
-    * Does the current hardware and kernel support MI_MATH and
-    * MI_LOAD_REGISTER_REG?
-    */
-   bool has_mi_math_and_lrr;
-
-   /**
     * Does the kernel support context reset notifications?
     */
    bool has_context_reset_notification;
 
    /**
-    * Does the kernel support pipelined register access?
-    * Due to whitelisting we need to do seperate checks
-    * for each register.
+    * Does the kernel support features such as pipelined register access to
+    * specific registers?
     */
-   unsigned hw_has_pipelined_register;
-#define HW_HAS_PIPELINED_SOL_OFFSET (1<<0)
+   unsigned kernel_features;
+#define KERNEL_ALLOWS_SOL_OFFSET_WRITES             (1<<0)
+#define KERNEL_ALLOWS_PREDICATE_WRITES              (1<<1)
+#define KERNEL_ALLOWS_MI_MATH_AND_LRR               (1<<2)
+#define KERNEL_ALLOWS_HSW_SCRATCH1_AND_ROW_CHICKEN3 (1<<3)
+#define KERNEL_ALLOWS_COMPUTE_DISPATCH              (1<<4)
 
    dri_bufmgr *bufmgr;
 
@@ -130,7 +127,31 @@
 static inline bool
 can_do_pipelined_register_writes(const struct intel_screen *screen)
 {
-   return screen->hw_has_pipelined_register & HW_HAS_PIPELINED_SOL_OFFSET;
+   return screen->kernel_features & KERNEL_ALLOWS_SOL_OFFSET_WRITES;
+}
+
+static inline bool
+can_do_hsw_l3_atomics(const struct intel_screen *screen)
+{
+   return screen->kernel_features & KERNEL_ALLOWS_HSW_SCRATCH1_AND_ROW_CHICKEN3;
+}
+
+static inline bool
+can_do_mi_math_and_lrr(const struct intel_screen *screen)
+{
+   return screen->kernel_features & KERNEL_ALLOWS_MI_MATH_AND_LRR;
+}
+
+static inline bool
+can_do_compute_dispatch(const struct intel_screen *screen)
+{
+   return screen->kernel_features & KERNEL_ALLOWS_COMPUTE_DISPATCH;
+}
+
+static inline bool
+can_do_predicate_writes(const struct intel_screen *screen)
+{
+   return screen->kernel_features & KERNEL_ALLOWS_PREDICATE_WRITES;
 }
 
 #endif