[Intel-gfx] [PATCH] drm/i915/gt: Apply Enable Boot Fetch to MBC control register

[Chris Wilson]

Mika spotted that we should be setting BIT(4) of MBCTL prior to
execution.

"The driver must set this bit in the following scenarios:
- To reload the HW boot context every time it gets loaded through the OS.
- After an FLR clears the register (the BIOS won’t run afterwards)."

Make it so.

Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
---
 drivers/gpu/drm/i915/gt/intel_workarounds.c | 18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_workarounds.c b/drivers/gpu/drm/i915/gt/intel_workarounds.c
index 61106129287f..bd3c0f7a9c8a 100644
--- a/drivers/gpu/drm/i915/gt/intel_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/intel_workarounds.c
@@ -680,6 +680,18 @@ int intel_engine_emit_ctx_wa(struct i915_request *rq)
 	return 0;
 }
 
+static void
+gen6_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
+{
+	wa_write_or(wal, GEN6_MBCTL, GEN6_MBCTL_ENABLE_BOOT_FETCH);
+}
+
+static void
+gen7_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
+{
+	wa_write_or(wal, GEN6_MBCTL, GEN6_MBCTL_ENABLE_BOOT_FETCH);
+}
+
 static void
 gen9_gt_workarounds_init(struct drm_i915_private *i915, struct i915_wa_list *wal)
 {
@@ -962,7 +974,11 @@ gt_init_workarounds(struct drm_i915_private *i915, struct i915_wa_list *wal)
 		bxt_gt_workarounds_init(i915, wal);
 	else if (IS_SKYLAKE(i915))
 		skl_gt_workarounds_init(i915, wal);
-	else if (INTEL_GEN(i915) <= 8)
+	else if (IS_GEN(i915, 7))
+		gen7_gt_workarounds_init(i915, wal);
+	else if (IS_GEN(i915, 6))
+		gen6_gt_workarounds_init(i915, wal);
+	else if (INTEL_GEN(i915) < 6)
 		return;
 	else
 		MISSING_CASE(INTEL_GEN(i915));
-- 
2.25.0