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);
+}