drm/xe: Introduce a new DRM driver for Intel GPUs

Xe, is a new driver for Intel GPUs that supports both integrated and
discrete platforms starting with Tiger Lake (first Intel Xe Architecture).

The code is at a stage where it is already functional and has experimental
support for multiple platforms starting from Tiger Lake, with initial
support implemented in Mesa (for Iris and Anv, our OpenGL and Vulkan
drivers), as well as in NEO (for OpenCL and Level0).

The new Xe driver leverages a lot from i915.

As for display, the intent is to share the display code with the i915
driver so that there is maximum reuse there. But it is not added
in this patch.

This initial work is a collaboration of many people and unfortunately
the big squashed patch won't fully honor the proper credits. But let's
get some git quick stats so we can at least try to preserve some of the
credits:

Co-developed-by: Matthew Brost <matthew.brost@intel.com>
Co-developed-by: Matthew Auld <matthew.auld@intel.com>
Co-developed-by: Matt Roper <matthew.d.roper@intel.com>
Co-developed-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Co-developed-by: Francois Dugast <francois.dugast@intel.com>
Co-developed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Co-developed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Co-developed-by: Philippe Lecluse <philippe.lecluse@intel.com>
Co-developed-by: Nirmoy Das <nirmoy.das@intel.com>
Co-developed-by: Jani Nikula <jani.nikula@intel.com>
Co-developed-by: José Roberto de Souza <jose.souza@intel.com>
Co-developed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Co-developed-by: Dave Airlie <airlied@redhat.com>
Co-developed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Co-developed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Co-developed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>

1 files changed, 157 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_preempt_fence.c b/drivers/gpu/drm/xe/xe_preempt_fence.c
new file mode 100644
index 000000000000..6ab9ff442766
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_preempt_fence.c
@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2022 Intel Corporation
+ */
+
+#include <linux/slab.h>
+
+#include "xe_engine.h"
+#include "xe_preempt_fence.h"
+#include "xe_vm.h"
+
+static void preempt_fence_work_func(struct work_struct *w)
+{
+	bool cookie = dma_fence_begin_signalling();
+	struct xe_preempt_fence *pfence =
+		container_of(w, typeof(*pfence), preempt_work);
+	struct xe_engine *e = pfence->engine;
+
+	if (pfence->error)
+		dma_fence_set_error(&pfence->base, pfence->error);
+	else
+		e->ops->suspend_wait(e);
+
+	dma_fence_signal(&pfence->base);
+	dma_fence_end_signalling(cookie);
+
+	queue_work(system_unbound_wq, &e->vm->preempt.rebind_work);
+
+	xe_engine_put(e);
+}
+
+static const char *
+preempt_fence_get_driver_name(struct dma_fence *fence)
+{
+	return "xe";
+}
+
+static const char *
+preempt_fence_get_timeline_name(struct dma_fence *fence)
+{
+	return "preempt";
+}
+
+static bool preempt_fence_enable_signaling(struct dma_fence *fence)
+{
+	struct xe_preempt_fence *pfence =
+		container_of(fence, typeof(*pfence), base);
+	struct xe_engine *e = pfence->engine;
+
+	pfence->error = e->ops->suspend(e);
+	queue_work(system_unbound_wq, &pfence->preempt_work);
+	return true;
+}
+
+static const struct dma_fence_ops preempt_fence_ops = {
+	.get_driver_name = preempt_fence_get_driver_name,
+	.get_timeline_name = preempt_fence_get_timeline_name,
+	.enable_signaling = preempt_fence_enable_signaling,
+};
+
+/**
+ * xe_preempt_fence_alloc() - Allocate a preempt fence with minimal
+ * initialization
+ *
+ * Allocate a preempt fence, and initialize its list head.
+ * If the preempt_fence allocated has been armed with
+ * xe_preempt_fence_arm(), it must be freed using dma_fence_put(). If not,
+ * it must be freed using xe_preempt_fence_free().
+ *
+ * Return: A struct xe_preempt_fence pointer used for calling into
+ * xe_preempt_fence_arm() or xe_preempt_fence_free().
+ * An error pointer on error.
+ */
+struct xe_preempt_fence *xe_preempt_fence_alloc(void)
+{
+	struct xe_preempt_fence *pfence;
+
+	pfence = kmalloc(sizeof(*pfence), GFP_KERNEL);
+	if (!pfence)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&pfence->link);
+	INIT_WORK(&pfence->preempt_work, preempt_fence_work_func);
+
+	return pfence;
+}
+
+/**
+ * xe_preempt_fence_free() - Free a preempt fence allocated using
+ * xe_preempt_fence_alloc().
+ * @pfence: pointer obtained from xe_preempt_fence_alloc();
+ *
+ * Free a preempt fence that has not yet been armed.
+ */
+void xe_preempt_fence_free(struct xe_preempt_fence *pfence)
+{
+	list_del(&pfence->link);
+	kfree(pfence);
+}
+
+/**
+ * xe_preempt_fence_arm() - Arm a preempt fence allocated using
+ * xe_preempt_fence_alloc().
+ * @pfence: The struct xe_preempt_fence pointer returned from
+ *          xe_preempt_fence_alloc().
+ * @e: The struct xe_engine used for arming.
+ * @context: The dma-fence context used for arming.
+ * @seqno: The dma-fence seqno used for arming.
+ *
+ * Inserts the preempt fence into @context's timeline, takes @link off any
+ * list, and registers the struct xe_engine as the xe_engine to be preempted.
+ *
+ * Return: A pointer to a struct dma_fence embedded into the preempt fence.
+ * This function doesn't error.
+ */
+struct dma_fence *
+xe_preempt_fence_arm(struct xe_preempt_fence *pfence, struct xe_engine *e,
+		     u64 context, u32 seqno)
+{
+	list_del_init(&pfence->link);
+	pfence->engine = xe_engine_get(e);
+	dma_fence_init(&pfence->base, &preempt_fence_ops,
+		      &e->compute.lock, context, seqno);
+
+	return &pfence->base;
+}
+
+/**
+ * xe_preempt_fence_create() - Helper to create and arm a preempt fence.
+ * @e: The struct xe_engine used for arming.
+ * @context: The dma-fence context used for arming.
+ * @seqno: The dma-fence seqno used for arming.
+ *
+ * Allocates and inserts the preempt fence into @context's timeline,
+ * and registers @e as the struct xe_engine to be preempted.
+ *
+ * Return: A pointer to the resulting struct dma_fence on success. An error
+ * pointer on error. In particular if allocation fails it returns
+ * ERR_PTR(-ENOMEM);
+ */
+struct dma_fence *
+xe_preempt_fence_create(struct xe_engine *e,
+			u64 context, u32 seqno)
+{
+	struct xe_preempt_fence *pfence;
+
+	pfence = xe_preempt_fence_alloc();
+	if (IS_ERR(pfence))
+		return ERR_CAST(pfence);
+
+	return xe_preempt_fence_arm(pfence, e, context, seqno);
+}
+
+bool xe_fence_is_xe_preempt(const struct dma_fence *fence)
+{
+	return fence->ops == &preempt_fence_ops;
+}