[PATCH 16/18] drm/i915/context: anonymous context interfaces

[Ben Widawsky <ben@bwidawsk.net>]

Ironlake RC6 needs to allocate a power context object which the hardware
can automatically switch to. Since the new context code nicely handles
contexts, create some interfaces so we can hook up the existing code to
the new code.

The right way to do this is to move a bunch of code out of
intel_display.c but I don't feel like doing it at this time. This patch
is a step in the right direction though.

CC: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
 drivers/gpu/drm/i915/i915_drv.h         |    3 +++
 drivers/gpu/drm/i915/i915_gem_context.c |   40 +++++++++++++++++++++++++++++--
 2 files changed, 41 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index d49615e..003b62e 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -280,6 +280,7 @@ struct i915_hw_ppgtt {
 
 /* This must match up with the value previously used for execbuf2.rsvd1. */
 #define DEFAULT_CONTEXT_ID 0
+#define ANONYMOUS_CONTEXT_ID 1
 struct i915_hw_context {
 	struct drm_i915_file_private *file_priv;
 	struct kref nref;
@@ -1316,6 +1317,8 @@ int i915_gem_context_create_ioctl(struct drm_device *dev, void *data,
 				  struct drm_file *file);
 int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
 				   struct drm_file *file);
+struct i915_hw_context *i915_context_alloc_anonymous(struct drm_device *dev);
+void i915_context_destroy_anonymous(struct i915_hw_context *ctx);
 
 /* i915_gem_gtt.c */
 int __must_check i915_gem_init_aliasing_ppgtt(struct drm_device *dev);
diff --git a/drivers/gpu/drm/i915/i915_gem_context.c b/drivers/gpu/drm/i915/i915_gem_context.c
index accb3de..de1f3ce 100644
--- a/drivers/gpu/drm/i915/i915_gem_context.c
+++ b/drivers/gpu/drm/i915/i915_gem_context.c
@@ -122,7 +122,7 @@ again:
 
 	spin_lock(&file_priv->context_lock);
 	ret = idr_get_new_above(&file_priv->context_idr, *ctx_out,
-				DEFAULT_CONTEXT_ID + 1, &id);
+				ANONYMOUS_CONTEXT_ID + 1, &id);
 	if (ret == 0)
 		(*ctx_out)->id = id;
 	spin_unlock(&file_priv->context_lock);
@@ -254,7 +254,7 @@ static int context_idr_cleanup(int id, void *p, void *data)
 	struct drm_i915_file_private *file_priv = file->driver_priv;
 	struct i915_hw_context *ctx;
 
-	BUG_ON(id == DEFAULT_CONTEXT_ID);
+	BUG_ON(id == DEFAULT_CONTEXT_ID || id == ANONYMOUS_CONTEXT_ID);
 	ctx = i915_gem_context_get(file_priv, id);
 	BUG_ON(ctx == NULL);
 	kref_put(&ctx->nref, destroy_hw_context);
@@ -380,6 +380,8 @@ int i915_switch_context(struct intel_ring_buffer *ring,
 	if (ring != &dev_priv->ring[RCS])
 		return 0;
 
+	BUG_ON(to_id == ANONYMOUS_CONTEXT_ID);
+
 	if (file)
 		file_priv = file->driver_priv;
 
@@ -475,3 +477,37 @@ int i915_gem_context_destroy_ioctl(struct drm_device *dev, void *data,
 	DRM_DEBUG_DRIVER("HW context %d destroyed\n", args->ctx_id);
 	return 0;
 }
+
+struct i915_hw_context *
+i915_context_alloc_anonymous(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct i915_hw_context *ctx;
+	int ret;
+
+	if (dev_priv->hw_contexts_disabled)
+		return NULL;
+
+	ret = create_hw_context(dev, NULL, &ctx);
+	if (ret)
+		return NULL;
+
+	ctx->id = ANONYMOUS_CONTEXT_ID;
+	ctx->obj->context_id = ANONYMOUS_CONTEXT_ID;
+
+	/* Anonymous contexts are assumed to be always pinned */
+	ret = i915_gem_object_pin(ctx->obj, CONTEXT_ALIGN, false);
+	if (ret)
+		do_destroy(ctx);
+
+	return ctx;
+}
+
+void i915_context_destroy_anonymous(struct i915_hw_context *ctx)
+{
+	BUG_ON(ctx->id != ANONYMOUS_CONTEXT_ID);
+	BUG_ON(ctx->obj->context_id != ANONYMOUS_CONTEXT_ID);
+
+	i915_gem_object_unpin(ctx->obj);
+	kref_put(&ctx->nref, destroy_hw_context);
+}
-- 
1.7.9.4