drm/i915: Consolidate forcewake code

As we now have forcewake domains, take advantage of it
by putting the differences in gen fw handling in data rather
than in code.

In past we have opencoded this quite extensively as the fw handling
is in the fast path. There has also been a lot of cargo-culted
copy'n'pasting from older gens to newer ones.

Now when the releasing of the forcewake is done by deferred timer,
it gives chance to consolidate more. Due to the frequency of actual hw
access being significantly less.

Take advantage of this and generalize the fw handling code
as much as possible. But we still aim to keep the forcewake sequence
particularities for each gen intact. So the access pattern
to fw engines should remain the same.

v2: - s/old_ack/clear_ack (Chris)
    - s/post_read/posting_read (Chris)
    - less polite commit msg (Chris)

v3: - rebase
    - check and clear wake_count in init

v4: - fix posting reads for gen8 (PRTS)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Reviewed-by: Deepak S <deepak.s@linux.intel.com> (v2)
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1294,17 +1294,12 @@ static int i915_gen6_forcewake_count_info(struct seq_file *m, void *data)
 	struct drm_device *dev = node->minor->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_uncore_forcewake_domain *fw_domain;
-	const char *domain_names[] = {
-		"render",
-		"blitter",
-		"media",
-	};
 	int i;
 
 	spin_lock_irq(&dev_priv->uncore.lock);
 	for_each_fw_domain(fw_domain, dev_priv, i) {
 		seq_printf(m, "%s.wake_count = %u\n",
-			   domain_names[i],
+			   intel_uncore_forcewake_domain_to_str(i),
 			   fw_domain->wake_count);
 	}
 	spin_unlock_irq(&dev_priv->uncore.lock);

drivers/gpu/drm/i915/i915_drv.h

@@ -617,6 +617,12 @@ struct intel_uncore {
 		int id;
 		unsigned wake_count;
 		struct timer_list timer;
+		u32 reg_set;
+		u32 val_set;
+		u32 val_clear;
+		u32 reg_ack;
+		u32 reg_post;
+		u32 val_reset;
 	} fw_domain[FW_DOMAIN_ID_COUNT];
 #define FORCEWAKE_RENDER	(1 << FW_DOMAIN_ID_RENDER)
 #define FORCEWAKE_BLITTER	(1 << FW_DOMAIN_ID_BLITTER)
@@ -2557,6 +2563,7 @@ extern void intel_uncore_init(struct drm_device *dev);
 extern void intel_uncore_check_errors(struct drm_device *dev);
 extern void intel_uncore_fini(struct drm_device *dev);
 extern void intel_uncore_forcewake_reset(struct drm_device *dev, bool restore);
+const char *intel_uncore_forcewake_domain_to_str(const int domain_id);
 
 void
 i915_enable_pipestat(struct drm_i915_private *dev_priv, enum pipe pipe,