drm/i915: Extract forcewake ack timeout

It's used all over the place, and we want to be able to play around with
the value, apparently. Note that it doesn't touch other timeouts of the
same value (like gtfifo, and thread C0 wait).
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
Reviewed-by: Chris Wilson <chris@chris-wilson.oc.uk>
[danvet: fixup conflict with vlv forcewake patches.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/intel_pm.c

@@ -31,6 +31,8 @@
 #include "../../../platform/x86/intel_ips.h"
 #include <linux/module.h>
 
+#define FORCEWAKE_ACK_TIMEOUT_US 500
+
 /* FBC, or Frame Buffer Compression, is a technique employed to compress the
  * framebuffer contents in-memory, aiming at reducing the required bandwidth
  * during in-memory transfers and, therefore, reduce the power packet.
@@ -3962,13 +3964,15 @@ static void __gen6_gt_force_wake_get(struct drm_i915_private *dev_priv)
 	else
 		forcewake_ack = FORCEWAKE_ACK;
 
-	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1) == 0, 500))
+	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1) == 0,
+			       FORCEWAKE_ACK_TIMEOUT_US))
 		DRM_ERROR("Timed out waiting for forcewake old ack to clear.\n");
 
 	I915_WRITE_NOTRACE(FORCEWAKE, 1);
 	POSTING_READ(FORCEWAKE);
 
-	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1), 500))
+	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1),
+			       FORCEWAKE_ACK_TIMEOUT_US))
 		DRM_ERROR("Timed out waiting for forcewake to ack request.\n");
 
 	__gen6_gt_wait_for_thread_c0(dev_priv);
@@ -3983,13 +3987,15 @@ static void __gen6_gt_force_wake_mt_get(struct drm_i915_private *dev_priv)
 	else
 		forcewake_ack = FORCEWAKE_MT_ACK;
 
-	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1) == 0, 500))
+	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1) == 0,
+			       FORCEWAKE_ACK_TIMEOUT_US))
 		DRM_ERROR("Timed out waiting for forcewake old ack to clear.\n");
 
 	I915_WRITE_NOTRACE(FORCEWAKE_MT, _MASKED_BIT_ENABLE(1));
 	POSTING_READ(FORCEWAKE_MT);
 
-	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1), 500))
+	if (wait_for_atomic_us((I915_READ_NOTRACE(forcewake_ack) & 1),
+			       FORCEWAKE_ACK_TIMEOUT_US))
 		DRM_ERROR("Timed out waiting for forcewake to ack request.\n");
 
 	__gen6_gt_wait_for_thread_c0(dev_priv);
@@ -4069,12 +4075,14 @@ int __gen6_gt_wait_for_fifo(struct drm_i915_private *dev_priv)
 
 static void vlv_force_wake_get(struct drm_i915_private *dev_priv)
 {
-	if (wait_for_atomic_us((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1) == 0, 500))
+	if (wait_for_atomic_us((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1) == 0,
+			       FORCEWAKE_ACK_TIMEOUT_US))
 		DRM_ERROR("Timed out waiting for forcewake old ack to clear.\n");
 
 	I915_WRITE_NOTRACE(FORCEWAKE_VLV, _MASKED_BIT_ENABLE(1));
 
-	if (wait_for_atomic_us((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1), 500))
+	if (wait_for_atomic_us((I915_READ_NOTRACE(FORCEWAKE_ACK_VLV) & 1),
+			       FORCEWAKE_ACK_TIMEOUT_US))
 		DRM_ERROR("Timed out waiting for forcewake to ack request.\n");
 
 	__gen6_gt_wait_for_thread_c0(dev_priv);