drm/i915: Introduce for_each_ring() macro

In many places we wish to iterate over the rings associated with the
GPU, so refactor them to use a common macro.

Along the way, there are a few code removals that should be side-effect
free and some rearrangement which should only have a cosmetic impact,
such as error-state.

Note that this slightly changes the semantics in the hangcheck code:
We now always cycle through all enabled rings instead of
short-circuiting the logic.

v2: Pull in a couple of suggestions from Ben and Daniel for
intel_ring_initialized() and not removing the warning (just moving them
to a new home, closer to the error).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
[danvet: Added note to commit message about the small behaviour
change, suggested by Ben Widawsky.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -699,6 +699,7 @@ static int i915_error_state(struct seq_file *m, void *unused)
 	struct drm_device *dev = error_priv->dev;
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_error_state *error = error_priv->error;
+	struct intel_ring_buffer *ring;
 	int i, j, page, offset, elt;
 
 	if (!error) {
@@ -706,7 +707,6 @@ static int i915_error_state(struct seq_file *m, void *unused)
 		return 0;
 	}
 
-
 	seq_printf(m, "Time: %ld s %ld us\n", error->time.tv_sec,
 		   error->time.tv_usec);
 	seq_printf(m, "PCI ID: 0x%04x\n", dev->pci_device);
@@ -722,11 +722,8 @@ static int i915_error_state(struct seq_file *m, void *unused)
 		seq_printf(m, "DONE_REG: 0x%08x\n", error->done_reg);
 	}
 
-	i915_ring_error_state(m, dev, error, RCS);
-	if (HAS_BLT(dev))
-		i915_ring_error_state(m, dev, error, BCS);
-	if (HAS_BSD(dev))
-		i915_ring_error_state(m, dev, error, VCS);
+	for_each_ring(ring, dev_priv, i)
+		i915_ring_error_state(m, dev, error, i);
 
 	if (error->active_bo)
 		print_error_buffers(m, "Active",

drivers/gpu/drm/i915/i915_drv.c

@@ -893,15 +893,15 @@ int i915_reset(struct drm_device *dev)
 	 */
 	if (drm_core_check_feature(dev, DRIVER_MODESET) ||
 			!dev_priv->mm.suspended) {
+		struct intel_ring_buffer *ring;
+		int i;
+
 		dev_priv->mm.suspended = 0;
 
 		i915_gem_init_swizzling(dev);
 
-		dev_priv->ring[RCS].init(&dev_priv->ring[RCS]);
-		if (HAS_BSD(dev))
-		    dev_priv->ring[VCS].init(&dev_priv->ring[VCS]);
-		if (HAS_BLT(dev))
-		    dev_priv->ring[BCS].init(&dev_priv->ring[BCS]);
+		for_each_ring(ring, dev_priv, i)
+			ring->init(ring);
 
 		i915_gem_init_ppgtt(dev);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -410,9 +410,7 @@ typedef struct drm_i915_private {
 #define DRM_I915_HANGCHECK_PERIOD 1500 /* in ms */
 	struct timer_list hangcheck_timer;
 	int hangcheck_count;
-	uint32_t last_acthd;
-	uint32_t last_acthd_bsd;
-	uint32_t last_acthd_blt;
+	uint32_t last_acthd[I915_NUM_RINGS];
 	uint32_t last_instdone;
 	uint32_t last_instdone1;
 
@@ -820,6 +818,11 @@ typedef struct drm_i915_private {
 	struct drm_property *force_audio_property;
 } drm_i915_private_t;
 
+/* Iterate over initialised rings */
+#define for_each_ring(ring__, dev_priv__, i__) \
+	for ((i__) = 0; (i__) < I915_NUM_RINGS; (i__)++) \
+		if (((ring__) = &(dev_priv__)->ring[(i__)]), intel_ring_initialized((ring__)))
+
 enum hdmi_force_audio {
 	HDMI_AUDIO_OFF_DVI = -2,	/* no aux data for HDMI-DVI converter */
 	HDMI_AUDIO_OFF,			/* force turn off HDMI audio */

drivers/gpu/drm/i915/i915_gem.c

@@ -1655,10 +1655,11 @@ void i915_gem_reset(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj;
+	struct intel_ring_buffer *ring;
 	int i;
 
-	for (i = 0; i < I915_NUM_RINGS; i++)
-		i915_gem_reset_ring_lists(dev_priv, &dev_priv->ring[i]);
+	for_each_ring(ring, dev_priv, i)
+		i915_gem_reset_ring_lists(dev_priv, ring);
 
 	/* Remove anything from the flushing lists. The GPU cache is likely
 	 * to be lost on reset along with the data, so simply move the
@@ -1763,10 +1764,11 @@ void
 i915_gem_retire_requests(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct intel_ring_buffer *ring;
 	int i;
 
-	for (i = 0; i < I915_NUM_RINGS; i++)
-		i915_gem_retire_requests_ring(&dev_priv->ring[i]);
+	for_each_ring(ring, dev_priv, i)
+		i915_gem_retire_requests_ring(ring);
 }
 
 static void
@@ -1774,6 +1776,7 @@ i915_gem_retire_work_handler(struct work_struct *work)
 {
 	drm_i915_private_t *dev_priv;
 	struct drm_device *dev;
+	struct intel_ring_buffer *ring;
 	bool idle;
 	int i;
 
@@ -1793,9 +1796,7 @@ i915_gem_retire_work_handler(struct work_struct *work)
 	 * objects indefinitely.
 	 */
 	idle = true;
-	for (i = 0; i < I915_NUM_RINGS; i++) {
-		struct intel_ring_buffer *ring = &dev_priv->ring[i];
-
+	for_each_ring(ring, dev_priv, i) {
 		if (!list_empty(&ring->gpu_write_list)) {
 			struct drm_i915_gem_request *request;
 			int ret;
@@ -2137,13 +2138,18 @@ static int i915_ring_idle(struct intel_ring_buffer *ring)
 int i915_gpu_idle(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct intel_ring_buffer *ring;
 	int ret, i;
 
 	/* Flush everything onto the inactive list. */
-	for (i = 0; i < I915_NUM_RINGS; i++) {
-		ret = i915_ring_idle(&dev_priv->ring[i]);
+	for_each_ring(ring, dev_priv, i) {
+		ret = i915_ring_idle(ring);
 		if (ret)
 			return ret;
+
+		/* Is the device fubar? */
+		if (WARN_ON(!list_empty(&ring->gpu_write_list)))
+			return -EBUSY;
 	}
 
 	return 0;
@@ -3463,9 +3469,7 @@ void i915_gem_init_ppgtt(struct drm_device *dev)
 		/* GFX_MODE is per-ring on gen7+ */
 	}
 
-	for (i = 0; i < I915_NUM_RINGS; i++) {
-		ring = &dev_priv->ring[i];
-
+	for_each_ring(ring, dev_priv, i) {
 		if (INTEL_INFO(dev)->gen >= 7)
 			I915_WRITE(RING_MODE_GEN7(ring),
 				   _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
@@ -3581,10 +3585,11 @@ void
 i915_gem_cleanup_ringbuffer(struct drm_device *dev)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct intel_ring_buffer *ring;
 	int i;
 
-	for (i = 0; i < I915_NUM_RINGS; i++)
-		intel_cleanup_ring_buffer(&dev_priv->ring[i]);
+	for_each_ring(ring, dev_priv, i)
+		intel_cleanup_ring_buffer(ring);
 }
 
 int
@@ -3592,7 +3597,7 @@ i915_gem_entervt_ioctl(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv)
 {
 	drm_i915_private_t *dev_priv = dev->dev_private;
-	int ret, i;
+	int ret;
 
 	if (drm_core_check_feature(dev, DRIVER_MODESET))
 		return 0;
@@ -3614,10 +3619,6 @@ i915_gem_entervt_ioctl(struct drm_device *dev, void *data,
 	BUG_ON(!list_empty(&dev_priv->mm.active_list));
 	BUG_ON(!list_empty(&dev_priv->mm.flushing_list));
 	BUG_ON(!list_empty(&dev_priv->mm.inactive_list));
-	for (i = 0; i < I915_NUM_RINGS; i++) {
-		BUG_ON(!list_empty(&dev_priv->ring[i].active_list));
-		BUG_ON(!list_empty(&dev_priv->ring[i].request_list));
-	}
 	mutex_unlock(&dev->struct_mutex);
 
 	ret = drm_irq_install(dev);

drivers/gpu/drm/i915/i915_gem_evict.c

@@ -168,7 +168,7 @@ i915_gem_evict_everything(struct drm_device *dev, bool purgeable_only)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	struct drm_i915_gem_object *obj, *next;
 	bool lists_empty;
-	int ret,i;
+	int ret;
 
 	lists_empty = (list_empty(&dev_priv->mm.inactive_list) &&
 		       list_empty(&dev_priv->mm.flushing_list) &&
@@ -178,17 +178,13 @@ i915_gem_evict_everything(struct drm_device *dev, bool purgeable_only)
 
 	trace_i915_gem_evict_everything(dev, purgeable_only);
 
-	ret = i915_gpu_idle(dev);
-	if (ret)
-		return ret;
-
 	/* The gpu_idle will flush everything in the write domain to the
 	 * active list. Then we must move everything off the active list
 	 * with retire requests.
 	 */
-	for (i = 0; i < I915_NUM_RINGS; i++)
-		if (WARN_ON(!list_empty(&dev_priv->ring[i].gpu_write_list)))
-			return -EBUSY;
+	ret = i915_gpu_idle(dev);
+	if (ret)
+		return ret;
 
 	i915_gem_retire_requests(dev);
 
@@ -203,5 +199,5 @@ i915_gem_evict_everything(struct drm_device *dev, bool purgeable_only)
 		}
 	}
 
-	return ret;
+	return 0;
 }

drivers/gpu/drm/i915/i915_irq.c

@@ -1022,15 +1022,11 @@ static void i915_gem_record_rings(struct drm_device *dev,
 				  struct drm_i915_error_state *error)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_ring_buffer *ring;
 	struct drm_i915_gem_request *request;
 	int i, count;
 
-	for (i = 0; i < I915_NUM_RINGS; i++) {
-		struct intel_ring_buffer *ring = &dev_priv->ring[i];
-
-		if (ring->obj == NULL)
-			continue;
-
+	for_each_ring(ring, dev_priv, i) {
 		i915_record_ring_state(dev, error, ring);
 
 		error->ring[i].batchbuffer =
@@ -1295,6 +1291,8 @@ static void i915_report_and_clear_eir(struct drm_device *dev)
 void i915_handle_error(struct drm_device *dev, bool wedged)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_ring_buffer *ring;
+	int i;
 
 	i915_capture_error_state(dev);
 	i915_report_and_clear_eir(dev);
@@ -1306,11 +1304,8 @@ void i915_handle_error(struct drm_device *dev, bool wedged)
 		/*
 		 * Wakeup waiting processes so they don't hang
 		 */
-		wake_up_all(&dev_priv->ring[RCS].irq_queue);
-		if (HAS_BSD(dev))
-			wake_up_all(&dev_priv->ring[VCS].irq_queue);
-		if (HAS_BLT(dev))
-			wake_up_all(&dev_priv->ring[BCS].irq_queue);
+		for_each_ring(ring, dev_priv, i)
+			wake_up_all(&ring->irq_queue);
 	}
 
 	queue_work(dev_priv->wq, &dev_priv->error_work);
@@ -1515,11 +1510,6 @@ ring_last_seqno(struct intel_ring_buffer *ring)
 
 static bool i915_hangcheck_ring_idle(struct intel_ring_buffer *ring, bool *err)
 {
-	/* We don't check whether the ring even exists before calling this
-	 * function. Hence check whether it's initialized. */
-	if (ring->obj == NULL)
-		return true;
-
 	if (list_empty(&ring->request_list) ||
 	    i915_seqno_passed(ring->get_seqno(ring), ring_last_seqno(ring))) {
 		/* Issue a wake-up to catch stuck h/w. */
@@ -1553,26 +1543,25 @@ static bool i915_hangcheck_hung(struct drm_device *dev)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 
 	if (dev_priv->hangcheck_count++ > 1) {
+		bool hung = true;
+
 		DRM_ERROR("Hangcheck timer elapsed... GPU hung\n");
 		i915_handle_error(dev, true);
 
 		if (!IS_GEN2(dev)) {
+			struct intel_ring_buffer *ring;
+			int i;
+
 			/* Is the chip hanging on a WAIT_FOR_EVENT?
 			 * If so we can simply poke the RB_WAIT bit
 			 * and break the hang. This should work on
 			 * all but the second generation chipsets.
 			 */
-			if (kick_ring(&dev_priv->ring[RCS]))
-				return false;
-
-			if (HAS_BSD(dev) && kick_ring(&dev_priv->ring[VCS]))
-				return false;
-
-			if (HAS_BLT(dev) && kick_ring(&dev_priv->ring[BCS]))
-				return false;
+			for_each_ring(ring, dev_priv, i)
+				hung &= !kick_ring(ring);
 		}
 
-		return true;
+		return hung;
 	}
 
 	return false;
@@ -1588,16 +1577,23 @@ void i915_hangcheck_elapsed(unsigned long data)
 {
 	struct drm_device *dev = (struct drm_device *)data;
 	drm_i915_private_t *dev_priv = dev->dev_private;
-	uint32_t acthd, instdone, instdone1, acthd_bsd, acthd_blt;
-	bool err = false;
+	uint32_t acthd[I915_NUM_RINGS], instdone, instdone1;
+	struct intel_ring_buffer *ring;
+	bool err = false, idle;
+	int i;
 
 	if (!i915_enable_hangcheck)
 		return;
 
+	memset(acthd, 0, sizeof(acthd));
+	idle = true;
+	for_each_ring(ring, dev_priv, i) {
+	    idle &= i915_hangcheck_ring_idle(ring, &err);
+	    acthd[i] = intel_ring_get_active_head(ring);
+	}
+
 	/* If all work is done then ACTHD clearly hasn't advanced. */
-	if (i915_hangcheck_ring_idle(&dev_priv->ring[RCS], &err) &&
-	    i915_hangcheck_ring_idle(&dev_priv->ring[VCS], &err) &&
-	    i915_hangcheck_ring_idle(&dev_priv->ring[BCS], &err)) {
+	if (idle) {
 		if (err) {
 			if (i915_hangcheck_hung(dev))
 				return;
@@ -1616,15 +1612,8 @@ void i915_hangcheck_elapsed(unsigned long data)
 		instdone = I915_READ(INSTDONE_I965);
 		instdone1 = I915_READ(INSTDONE1);
 	}
-	acthd = intel_ring_get_active_head(&dev_priv->ring[RCS]);
-	acthd_bsd = HAS_BSD(dev) ?
-		intel_ring_get_active_head(&dev_priv->ring[VCS]) : 0;
-	acthd_blt = HAS_BLT(dev) ?
-		intel_ring_get_active_head(&dev_priv->ring[BCS]) : 0;
 
-	if (dev_priv->last_acthd == acthd &&
-	    dev_priv->last_acthd_bsd == acthd_bsd &&
-	    dev_priv->last_acthd_blt == acthd_blt &&
+	if (memcmp(dev_priv->last_acthd, acthd, sizeof(acthd)) == 0 &&
 	    dev_priv->last_instdone == instdone &&
 	    dev_priv->last_instdone1 == instdone1) {
 		if (i915_hangcheck_hung(dev))
@@ -1632,9 +1621,7 @@ void i915_hangcheck_elapsed(unsigned long data)
 	} else {
 		dev_priv->hangcheck_count = 0;
 
-		dev_priv->last_acthd = acthd;
-		dev_priv->last_acthd_bsd = acthd_bsd;
-		dev_priv->last_acthd_blt = acthd_blt;
+		memcpy(dev_priv->last_acthd, acthd, sizeof(acthd));
 		dev_priv->last_instdone = instdone;
 		dev_priv->last_instdone1 = instdone1;
 	}

drivers/gpu/drm/i915/intel_pm.c

@@ -2326,6 +2326,7 @@ int intel_enable_rc6(const struct drm_device *dev)
 
 void gen6_enable_rps(struct drm_i915_private *dev_priv)
 {
+	struct intel_ring_buffer *ring;
 	u32 rp_state_cap = I915_READ(GEN6_RP_STATE_CAP);
 	u32 gt_perf_status = I915_READ(GEN6_GT_PERF_STATUS);
 	u32 pcu_mbox, rc6_mask = 0;
@@ -2360,8 +2361,8 @@ void gen6_enable_rps(struct drm_i915_private *dev_priv)
 	I915_WRITE(GEN6_RC_EVALUATION_INTERVAL, 125000);
 	I915_WRITE(GEN6_RC_IDLE_HYSTERSIS, 25);
 
-	for (i = 0; i < I915_NUM_RINGS; i++)
-		I915_WRITE(RING_MAX_IDLE(dev_priv->ring[i].mmio_base), 10);
+	for_each_ring(ring, dev_priv, i)
+		I915_WRITE(RING_MAX_IDLE(ring->mmio_base), 10);
 
 	I915_WRITE(GEN6_RC_SLEEP, 0);
 	I915_WRITE(GEN6_RC1e_THRESHOLD, 1000);

drivers/gpu/drm/i915/intel_ringbuffer.h

@@ -119,6 +119,12 @@ struct  intel_ring_buffer {
 	void *private;
 };
 
+static inline bool
+intel_ring_initialized(struct intel_ring_buffer *ring)
+{
+	return ring->obj != NULL;
+}
+
 static inline unsigned
 intel_ring_flag(struct intel_ring_buffer *ring)
 {