[Intel-gfx] [PATCH 07/23] drm/i915: add forcewake functions that don't touch runtime PM

[Paulo Zanoni]

From: Paulo Zanoni <paulo.r.zanoni at intel.com>

To solve a chicken-and-egg problem. Currently when we get/put
forcewake we also get/put runtime PM and this works fine because the
runtime PM code doesn't need forcewake. But we're going to merge PC8
and runtime PM into a single feature, and the PC8 code (the LCPLL
code) does need the forcewake, so that specific piece of code needs to
call the _no_rpm version so it doesn't try to get runtime PM in the
code that gets runtime PM.

For now the new functions are unused, we'll use them on the patch that
merges PC8 with runtime PM.

Also notice that, so simplify things, the put() function doesn't use
the workqueue, since the workqueue also puts runtime PM.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.h     |  4 ++++
 drivers/gpu/drm/i915/intel_uncore.c | 40 +++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 2a2a3a9..dcaa130 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -2604,6 +2604,10 @@ extern void intel_display_print_error_state(struct drm_i915_error_state_buf *e,
  */
 void gen6_gt_force_wake_get(struct drm_i915_private *dev_priv, int fw_engine);
 void gen6_gt_force_wake_put(struct drm_i915_private *dev_priv, int fw_engine);
+void gen6_gt_force_wake_get_no_rpm(struct drm_i915_private *dev_priv,
+				   int fw_engine);
+void gen6_gt_force_wake_put_no_rpm(struct drm_i915_private *dev_priv,
+				   int fw_engine);
 
 int sandybridge_pcode_read(struct drm_i915_private *dev_priv, u8 mbox, u32 *val);
 int sandybridge_pcode_write(struct drm_i915_private *dev_priv, u8 mbox, u32 val);
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 6a21f43..d0ec32a 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -422,6 +422,46 @@ out:
 		intel_runtime_pm_put(dev_priv);
 }
 
+/*
+ * These two _no_rpm functions below should only be used by the code that runs
+ * while we are enabling/disabling runtiem PM. See gen6_gt_force_wake_get().
+ */
+void gen6_gt_force_wake_get_no_rpm(struct drm_i915_private *dev_priv,
+				   int fw_engine)
+{
+	unsigned long irqflags;
+
+	if (!dev_priv->uncore.funcs.force_wake_get)
+		return;
+
+	/* Redirect to VLV specific routine */
+	if (IS_VALLEYVIEW(dev_priv->dev))
+		return vlv_force_wake_get(dev_priv, fw_engine);
+
+	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
+	if (dev_priv->uncore.forcewake_count++ == 0)
+		dev_priv->uncore.funcs.force_wake_get(dev_priv, FORCEWAKE_ALL);
+	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
+}
+
+void gen6_gt_force_wake_put_no_rpm(struct drm_i915_private *dev_priv,
+				   int fw_engine)
+{
+	unsigned long irqflags;
+
+	if (!dev_priv->uncore.funcs.force_wake_put)
+		return;
+
+	/* Redirect to VLV specific routine */
+	if (IS_VALLEYVIEW(dev_priv->dev))
+		return vlv_force_wake_put(dev_priv, fw_engine);
+
+	spin_lock_irqsave(&dev_priv->uncore.lock, irqflags);
+	if (--dev_priv->uncore.forcewake_count == 0)
+		dev_priv->uncore.funcs.force_wake_put(dev_priv, FORCEWAKE_ALL);
+	spin_unlock_irqrestore(&dev_priv->uncore.lock, irqflags);
+}
+
 /* We give fast paths for the really cool registers */
 #define NEEDS_FORCE_WAKE(dev_priv, reg) \
 	 ((reg) < 0x40000 && (reg) != FORCEWAKE)
-- 
1.8.5.3