drm/i915: Store number of active engines in device info

Until now code was calling hweight32 to figure out the
number from device_info->ring_mask at runtime. Instead
we can cache it at engine init time and use directly.
Signed-off-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: NDave Gordon <david.s.gordon@intel.com>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Link: http://patchwork.freedesktop.org/patch/msgid/1470842530-35854-1-git-send-email-tvrtko.ursulin@linux.intel.com

drivers/gpu/drm/i915/i915_debugfs.c

@@ -3226,7 +3226,7 @@ static int i915_semaphore_status(struct seq_file *m, void *unused)
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct intel_engine_cs *engine;
-	int num_rings = hweight32(INTEL_INFO(dev)->ring_mask);
+	int num_rings = INTEL_INFO(dev)->num_rings;
 	enum intel_engine_id id;
 	int j, ret;
 

drivers/gpu/drm/i915/i915_drv.h

@@ -793,6 +793,7 @@ struct intel_device_info {
 	u8 gen;
 	u16 gen_mask;
 	u8 ring_mask; /* Rings supported by the HW */
+	u8 num_rings;
 	DEV_INFO_FOR_EACH_FLAG(DEFINE_FLAG, SEP_SEMICOLON);
 	/* Register offsets for the various display pipes and transcoders */
 	int pipe_offsets[I915_MAX_TRANSCODERS];

drivers/gpu/drm/i915/i915_gem_context.c

@@ -568,7 +568,7 @@ mi_set_context(struct drm_i915_gem_request *req, u32 hw_flags)
 	const int num_rings =
 		/* Use an extended w/a on ivb+ if signalling from other rings */
 		i915.semaphores ?
-		hweight32(INTEL_INFO(dev_priv)->ring_mask) - 1 :
+		INTEL_INFO(dev_priv)->num_rings - 1 :
 		0;
 	int len, ret;
 

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -109,6 +109,7 @@ intel_engine_setup(struct drm_i915_private *dev_priv,
 int intel_engines_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct intel_device_info *device_info = mkwrite_device_info(dev_priv);
 	unsigned int mask = 0;
 	int (*init)(struct intel_engine_cs *engine);
 	unsigned int i;
@@ -142,11 +143,10 @@ int intel_engines_init(struct drm_device *dev)
 	 * are added to the driver by a warning and disabling the forgotten
 	 * engines.
 	 */
-	if (WARN_ON(mask != INTEL_INFO(dev_priv)->ring_mask)) {
-		struct intel_device_info *info =
-			(struct intel_device_info *)&dev_priv->info;
-		info->ring_mask = mask;
-	}
+	if (WARN_ON(mask != INTEL_INFO(dev_priv)->ring_mask))
+		device_info->ring_mask = mask;
+
+	device_info->num_rings = hweight32(mask);
 
 	return 0;
 

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -1317,7 +1317,7 @@ static int gen8_rcs_signal(struct drm_i915_gem_request *req)
 	enum intel_engine_id id;
 	int ret, num_rings;
 
-	num_rings = hweight32(INTEL_INFO(dev_priv)->ring_mask);
+	num_rings = INTEL_INFO(dev_priv)->num_rings;
 	ret = intel_ring_begin(req, (num_rings-1) * 8);
 	if (ret)
 		return ret;
@@ -1354,7 +1354,7 @@ static int gen8_xcs_signal(struct drm_i915_gem_request *req)
 	enum intel_engine_id id;
 	int ret, num_rings;
 
-	num_rings = hweight32(INTEL_INFO(dev_priv)->ring_mask);
+	num_rings = INTEL_INFO(dev_priv)->num_rings;
 	ret = intel_ring_begin(req, (num_rings-1) * 6);
 	if (ret)
 		return ret;
@@ -1389,7 +1389,7 @@ static int gen6_signal(struct drm_i915_gem_request *req)
 	enum intel_engine_id id;
 	int ret, num_rings;
 
-	num_rings = hweight32(INTEL_INFO(dev_priv)->ring_mask);
+	num_rings = INTEL_INFO(dev_priv)->num_rings;
 	ret = intel_ring_begin(req, round_up((num_rings-1) * 3, 2));
 	if (ret)
 		return ret;