--- /dev/null
+/*
+ * Copyright © 2011-2012 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ * Ben Widawsky <ben@bwidawsk.net>
+ *
+ */
+
+/*
+ * This file implements HW context support. On gen5+ a HW context consists of an
+ * opaque GPU object which is referenced at times of context saves and restores.
+ * With RC6 enabled, the context is also referenced as the GPU enters and exists
+ * from RC6 (GPU has it's own internal power context, except on gen5). Though
+ * something like a context does exist for the media ring, the code only
+ * supports contexts for the render ring.
+ *
+ * In software, there is a distinction between contexts created by the user,
+ * and the default HW context. The default HW context is used by GPU clients
+ * that do not request setup of their own hardware context. The default
+ * context's state is never restored to help prevent programming errors. This
+ * would happen if a client ran and piggy-backed off another clients GPU state.
+ * The default context only exists to give the GPU some offset to load as the
+ * current to invoke a save of the context we actually care about. In fact, the
+ * code could likely be constructed, albeit in a more complicated fashion, to
+ * never use the default context, though that limits the driver's ability to
+ * swap out, and/or destroy other contexts.
+ *
+ * All other contexts are created as a request by the GPU client. These contexts
+ * store GPU state, and thus allow GPU clients to not re-emit state (and
+ * potentially query certain state) at any time. The kernel driver makes
+ * certain that the appropriate commands are inserted.
+ *
+ * The context life cycle is semi-complicated in that context BOs may live
+ * longer than the context itself because of the way the hardware, and object
+ * tracking works. Below is a very crude representation of the state machine
+ * describing the context life.
+ * refcount pincount active
+ * S0: initial state 0 0 0
+ * S1: context created 1 0 0
+ * S2: context is currently running 2 1 X
+ * S3: GPU referenced, but not current 2 0 1
+ * S4: context is current, but destroyed 1 1 0
+ * S5: like S3, but destroyed 1 0 1
+ *
+ * The most common (but not all) transitions:
+ * S0->S1: client creates a context
+ * S1->S2: client submits execbuf with context
+ * S2->S3: other clients submits execbuf with context
+ * S3->S1: context object was retired
+ * S3->S2: clients submits another execbuf
+ * S2->S4: context destroy called with current context
+ * S3->S5->S0: destroy path
+ * S4->S5->S0: destroy path on current context
+ *
+ * There are two confusing terms used above:
+ * The "current context" means the context which is currently running on the
+ * GPU. The GPU has loaded it's state already and has stored away the gtt
+ * offset of the BO. The GPU is not actively referencing the data at this
+ * offset, but it will on the next context switch. The only way to avoid this
+ * is to do a GPU reset.
+ *
+ * An "active context' is one which was previously the "current context" and is
+ * on the active list waiting for the next context switch to occur. Until this
+ * happens, the object must remain at the same gtt offset. It is therefore
+ * possible to destroy a context, but it is still active.
+ *
+ */
+
+#include "drmP.h"
+#include "i915_drm.h"
+#include "i915_drv.h"
+
+static int get_context_size(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ int ret;
+ u32 reg;
+
+ switch (INTEL_INFO(dev)->gen) {
+ case 6:
+ reg = I915_READ(CXT_SIZE);
+ ret = GEN6_CXT_TOTAL_SIZE(reg) * 64;
+ break;
+ case 7:
+ reg = I915_READ(GEN7_CTX_SIZE);
+ ret = GEN7_CTX_TOTAL_SIZE(reg) * 64;
+ break;
+ default:
+ BUG();
+ }
+
+ return ret;
+}
+
+/**
+ * The default context needs to exist per ring that uses contexts. It stores the
+ * context state of the GPU for applications that don't utilize HW contexts, as
+ * well as an idle case.
+ */
+static int create_default_context(struct drm_i915_private *dev_priv)
+{
+ return 0;
+}
+
+void i915_gem_context_init(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ uint32_t ctx_size;
+
+ if (!HAS_HW_CONTEXTS(dev))
+ return;
+
+ /* If called from reset, or thaw... we've been here already */
+ if (dev_priv->hw_contexts_disabled)
+ return;
+
+ ctx_size = get_context_size(dev);
+ dev_priv->hw_context_size = get_context_size(dev);
+ dev_priv->hw_context_size = round_up(dev_priv->hw_context_size, 4096);
+
+ if (ctx_size <= 0 || ctx_size > (1<<20)) {
+ dev_priv->hw_contexts_disabled = true;
+ return;
+ }
+
+ if (create_default_context(dev_priv)) {
+ dev_priv->hw_contexts_disabled = true;
+ return;
+ }
+
+ DRM_DEBUG_DRIVER("HW context support initialized\n");
+}
+
+void i915_gem_context_fini(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ if (dev_priv->hw_contexts_disabled)
+ return;
+}
+
+void i915_gem_context_open(struct drm_device *dev, struct drm_file *file)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ if (dev_priv->hw_contexts_disabled)
+ return;
+}
+
+void i915_gem_context_close(struct drm_device *dev, struct drm_file *file)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ if (dev_priv->hw_contexts_disabled)
+ return;
+}
projects / firefly-linux-kernel-4.4.55.git / commitdiff