[Intel-gfx] [PATCH v2 1/2] drm/i915/gen8: The WA BB framework is enabled.

[Arun Siluvery]

From: Namrta <namrta.salonie at intel.com>

This can be used to enable WA BB infrastructure for features like
RC6, SSEU and in between context save/restore etc.

The patch which would need WA BB will have to declare the wa_bb obj
utilizing the function here. Update the WA BB with required commands
and update the address of the WA BB at appropriate place.

v2: Move function to the right place to keeps diffs clearer in the
patch that uses this function (Michel)

Change-Id: I9cc49ae7426560215e7b6a6d10ba411caeb9321b
Signed-off-by: Namrta <namrta.salonie at intel.com>
Signed-off-by: Arun Siluvery <arun.siluvery at linux.intel.com>
Reviewed-by: Michel Thierry <michel.thierry at intel.com>
---
 drivers/gpu/drm/i915/intel_lrc.c | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
index 9c851d8..ea37a56 100644
--- a/drivers/gpu/drm/i915/intel_lrc.c
+++ b/drivers/gpu/drm/i915/intel_lrc.c
@@ -1107,6 +1107,38 @@ static int intel_logical_ring_workarounds_emit(struct intel_engine_cs *ring,
 	return 0;
 }
 
+static struct intel_ringbuffer *
+create_wa_bb(struct intel_engine_cs *ring, uint32_t bb_size)
+{
+	struct drm_device *dev = ring->dev;
+	struct intel_ringbuffer *ringbuf;
+	int ret;
+
+	ringbuf = kzalloc(sizeof(*ringbuf), GFP_KERNEL);
+	if (!ringbuf)
+		return NULL;
+
+	ringbuf->ring = ring;
+
+	ringbuf->size = roundup(bb_size, PAGE_SIZE);
+	ringbuf->effective_size = ringbuf->size;
+	ringbuf->head = 0;
+	ringbuf->tail = 0;
+	ringbuf->space = ringbuf->size;
+	ringbuf->last_retired_head = -1;
+
+	ret = intel_alloc_ringbuffer_obj(dev, ringbuf);
+	if (ret) {
+		DRM_DEBUG_DRIVER(
+		"Failed to allocate ringbuf obj for wa_bb%s: %d\n",
+		ring->name, ret);
+		kfree(ringbuf);
+		return NULL;
+	}
+
+	return ringbuf;
+}
+
 static int gen8_init_common_ring(struct intel_engine_cs *ring)
 {
 	struct drm_device *dev = ring->dev;
-- 
2.3.0