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, 276 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_sync.c b/drivers/gpu/drm/xe/xe_sync.c
new file mode 100644
index 000000000000..0fbd8d0978cf
--- /dev/null
+++ b/drivers/gpu/drm/xe/xe_sync.c
@@ -0,0 +1,276 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2021 Intel Corporation
+ */
+
+#include "xe_sync.h"
+
+#include <linux/kthread.h>
+#include <linux/sched/mm.h>
+#include <linux/uaccess.h>
+#include <drm/xe_drm.h>
+#include <drm/drm_print.h>
+#include <drm/drm_syncobj.h>
+
+#include "xe_device_types.h"
+#include "xe_sched_job_types.h"
+#include "xe_macros.h"
+
+#define SYNC_FLAGS_TYPE_MASK 0x3
+#define SYNC_FLAGS_FENCE_INSTALLED	0x10000
+
+struct user_fence {
+	struct xe_device *xe;
+	struct kref refcount;
+	struct dma_fence_cb cb;
+	struct work_struct worker;
+	struct mm_struct *mm;
+	u64 __user *addr;
+	u64 value;
+};
+
+static void user_fence_destroy(struct kref *kref)
+{
+	struct user_fence *ufence = container_of(kref, struct user_fence,
+						 refcount);
+
+	mmdrop(ufence->mm);
+	kfree(ufence);
+}
+
+static void user_fence_get(struct user_fence *ufence)
+{
+	kref_get(&ufence->refcount);
+}
+
+static void user_fence_put(struct user_fence *ufence)
+{
+	kref_put(&ufence->refcount, user_fence_destroy);
+}
+
+static struct user_fence *user_fence_create(struct xe_device *xe, u64 addr,
+					    u64 value)
+{
+	struct user_fence *ufence;
+
+	ufence = kmalloc(sizeof(*ufence), GFP_KERNEL);
+	if (!ufence)
+		return NULL;
+
+	ufence->xe = xe;
+	kref_init(&ufence->refcount);
+	ufence->addr = u64_to_user_ptr(addr);
+	ufence->value = value;
+	ufence->mm = current->mm;
+	mmgrab(ufence->mm);
+
+	return ufence;
+}
+
+static void user_fence_worker(struct work_struct *w)
+{
+	struct user_fence *ufence = container_of(w, struct user_fence, worker);
+
+	if (mmget_not_zero(ufence->mm)) {
+		kthread_use_mm(ufence->mm);
+		if (copy_to_user(ufence->addr, &ufence->value, sizeof(ufence->value)))
+			XE_WARN_ON("Copy to user failed");
+		kthread_unuse_mm(ufence->mm);
+		mmput(ufence->mm);
+	}
+
+	wake_up_all(&ufence->xe->ufence_wq);
+	user_fence_put(ufence);
+}
+
+static void kick_ufence(struct user_fence *ufence, struct dma_fence *fence)
+{
+	INIT_WORK(&ufence->worker, user_fence_worker);
+	queue_work(ufence->xe->ordered_wq, &ufence->worker);
+	dma_fence_put(fence);
+}
+
+static void user_fence_cb(struct dma_fence *fence, struct dma_fence_cb *cb)
+{
+	struct user_fence *ufence = container_of(cb, struct user_fence, cb);
+
+	kick_ufence(ufence, fence);
+}
+
+int xe_sync_entry_parse(struct xe_device *xe, struct xe_file *xef,
+			struct xe_sync_entry *sync,
+			struct drm_xe_sync __user *sync_user,
+			bool exec, bool no_dma_fences)
+{
+	struct drm_xe_sync sync_in;
+	int err;
+
+	if (copy_from_user(&sync_in, sync_user, sizeof(*sync_user)))
+		return -EFAULT;
+
+	if (XE_IOCTL_ERR(xe, sync_in.flags &
+			 ~(SYNC_FLAGS_TYPE_MASK | DRM_XE_SYNC_SIGNAL)))
+		return -EINVAL;
+
+	switch (sync_in.flags & SYNC_FLAGS_TYPE_MASK) {
+	case DRM_XE_SYNC_SYNCOBJ:
+		if (XE_IOCTL_ERR(xe, no_dma_fences))
+			return -ENOTSUPP;
+
+		if (XE_IOCTL_ERR(xe, upper_32_bits(sync_in.addr)))
+			return -EINVAL;
+
+		sync->syncobj = drm_syncobj_find(xef->drm, sync_in.handle);
+		if (XE_IOCTL_ERR(xe, !sync->syncobj))
+			return -ENOENT;
+
+		if (!(sync_in.flags & DRM_XE_SYNC_SIGNAL)) {
+			sync->fence = drm_syncobj_fence_get(sync->syncobj);
+			if (XE_IOCTL_ERR(xe, !sync->fence))
+				return -EINVAL;
+		}
+		break;
+
+	case DRM_XE_SYNC_TIMELINE_SYNCOBJ:
+		if (XE_IOCTL_ERR(xe, no_dma_fences))
+			return -ENOTSUPP;
+
+		if (XE_IOCTL_ERR(xe, upper_32_bits(sync_in.addr)))
+			return -EINVAL;
+
+		if (XE_IOCTL_ERR(xe, sync_in.timeline_value == 0))
+			return -EINVAL;
+
+		sync->syncobj = drm_syncobj_find(xef->drm, sync_in.handle);
+		if (XE_IOCTL_ERR(xe, !sync->syncobj))
+			return -ENOENT;
+
+		if (sync_in.flags & DRM_XE_SYNC_SIGNAL) {
+			sync->chain_fence = dma_fence_chain_alloc();
+			if (!sync->chain_fence)
+				return -ENOMEM;
+		} else {
+			sync->fence = drm_syncobj_fence_get(sync->syncobj);
+			if (XE_IOCTL_ERR(xe, !sync->fence))
+				return -EINVAL;
+
+			err = dma_fence_chain_find_seqno(&sync->fence,
+							 sync_in.timeline_value);
+			if (err)
+				return err;
+		}
+		break;
+
+	case DRM_XE_SYNC_DMA_BUF:
+		if (XE_IOCTL_ERR(xe, "TODO"))
+			return -EINVAL;
+		break;
+
+	case DRM_XE_SYNC_USER_FENCE:
+		if (XE_IOCTL_ERR(xe, !(sync_in.flags & DRM_XE_SYNC_SIGNAL)))
+			return -ENOTSUPP;
+
+		if (XE_IOCTL_ERR(xe, sync_in.addr & 0x7))
+			return -EINVAL;
+
+		if (exec) {
+			sync->addr = sync_in.addr;
+		} else {
+			sync->ufence = user_fence_create(xe, sync_in.addr,
+							 sync_in.timeline_value);
+			if (XE_IOCTL_ERR(xe, !sync->ufence))
+				return -ENOMEM;
+		}
+
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	sync->flags = sync_in.flags;
+	sync->timeline_value = sync_in.timeline_value;
+
+	return 0;
+}
+
+int xe_sync_entry_wait(struct xe_sync_entry *sync)
+{
+	if (sync->fence)
+		dma_fence_wait(sync->fence, true);
+
+	return 0;
+}
+
+int xe_sync_entry_add_deps(struct xe_sync_entry *sync, struct xe_sched_job *job)
+{
+	int err;
+
+	if (sync->fence) {
+		err = drm_sched_job_add_dependency(&job->drm,
+						   dma_fence_get(sync->fence));
+		if (err) {
+			dma_fence_put(sync->fence);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+bool xe_sync_entry_signal(struct xe_sync_entry *sync, struct xe_sched_job *job,
+			  struct dma_fence *fence)
+{
+	if (!(sync->flags & DRM_XE_SYNC_SIGNAL) ||
+	    sync->flags & SYNC_FLAGS_FENCE_INSTALLED)
+		return false;
+
+	if (sync->chain_fence) {
+		drm_syncobj_add_point(sync->syncobj, sync->chain_fence,
+				      fence, sync->timeline_value);
+		/*
+		 * The chain's ownership is transferred to the
+		 * timeline.
+		 */
+		sync->chain_fence = NULL;
+	} else if (sync->syncobj) {
+		drm_syncobj_replace_fence(sync->syncobj, fence);
+	} else if (sync->ufence) {
+		int err;
+
+		dma_fence_get(fence);
+		user_fence_get(sync->ufence);
+		err = dma_fence_add_callback(fence, &sync->ufence->cb,
+					     user_fence_cb);
+		if (err == -ENOENT) {
+			kick_ufence(sync->ufence, fence);
+		} else if (err) {
+			XE_WARN_ON("failed to add user fence");
+			user_fence_put(sync->ufence);
+			dma_fence_put(fence);
+		}
+	} else if ((sync->flags & SYNC_FLAGS_TYPE_MASK) ==
+		   DRM_XE_SYNC_USER_FENCE) {
+		job->user_fence.used = true;
+		job->user_fence.addr = sync->addr;
+		job->user_fence.value = sync->timeline_value;
+	}
+
+	/* TODO: external BO? */
+
+	sync->flags |= SYNC_FLAGS_FENCE_INSTALLED;
+
+	return true;
+}
+
+void xe_sync_entry_cleanup(struct xe_sync_entry *sync)
+{
+	if (sync->syncobj)
+		drm_syncobj_put(sync->syncobj);
+	if (sync->fence)
+		dma_fence_put(sync->fence);
+	if (sync->chain_fence)
+		dma_fence_put(&sync->chain_fence->base);
+	if (sync->ufence)
+		user_fence_put(sync->ufence);
+}