drm/msm: Add per-instance submit queues

Currently the behavior of a command stream is provided by the user
application during submission and the application is expected to internally
maintain the settings for each 'context' or 'rendering queue' and specify
the correct ones.

This works okay for simple cases but as applications become more
complex we will want to set context specific flags and do various
permission checks to allow certain contexts to enable additional
privileges.

Add kernel-side submit queues to be analogous to 'contexts' or
'rendering queues' on the application side. Each file descriptor
instance will maintain its own list of queues. Queues cannot be
shared between file descriptors.

For backwards compatibility context id '0' is defined as a default
context specifying no priority and no special flags. This is
intended to be the usual configuration for 99% of applications so
that a garden variety application can function correctly without
creating a queue. Only those applications requiring the specific
benefit of different queues need create one.

Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

1 files changed, 135 insertions, 0 deletions

diff --git a/drivers/gpu/drm/msm/msm_submitqueue.c b/drivers/gpu/drm/msm/msm_submitqueue.c
new file mode 100644
index 0000000..593c3b5
--- /dev/null
+++ b/drivers/gpu/drm/msm/msm_submitqueue.c
@@ -0,0 +1,135 @@
+/* Copyright (c) 2017 The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/kref.h>
+#include "msm_gpu.h"
+
+void msm_submitqueue_destroy(struct kref *kref)
+{
+	struct msm_gpu_submitqueue *queue = container_of(kref,
+		struct msm_gpu_submitqueue, ref);
+
+	kfree(queue);
+}
+
+struct msm_gpu_submitqueue *msm_submitqueue_get(struct msm_file_private *ctx,
+		u32 id)
+{
+	struct msm_gpu_submitqueue *entry;
+
+	if (!ctx)
+		return NULL;
+
+	read_lock(&ctx->queuelock);
+
+	list_for_each_entry(entry, &ctx->submitqueues, node) {
+		if (entry->id == id) {
+			kref_get(&entry->ref);
+			read_unlock(&ctx->queuelock);
+
+			return entry;
+		}
+	}
+
+	read_unlock(&ctx->queuelock);
+	return NULL;
+}
+
+void msm_submitqueue_close(struct msm_file_private *ctx)
+{
+	struct msm_gpu_submitqueue *entry, *tmp;
+
+	if (!ctx)
+		return;
+
+	/*
+	 * No lock needed in close and there won't
+	 * be any more user ioctls coming our way
+	 */
+	list_for_each_entry_safe(entry, tmp, &ctx->submitqueues, node)
+		msm_submitqueue_put(entry);
+}
+
+int msm_submitqueue_create(struct msm_file_private *ctx, u32 prio, u32 flags,
+		u32 *id)
+{
+	struct msm_gpu_submitqueue *queue;
+
+	if (!ctx)
+		return -ENODEV;
+
+	queue = kzalloc(sizeof(*queue), GFP_KERNEL);
+
+	if (!queue)
+		return -ENOMEM;
+
+	kref_init(&queue->ref);
+	queue->flags = flags;
+	queue->prio = prio;
+
+	write_lock(&ctx->queuelock);
+
+	queue->id = ctx->queueid++;
+
+	if (id)
+		*id = queue->id;
+
+	list_add_tail(&queue->node, &ctx->submitqueues);
+
+	write_unlock(&ctx->queuelock);
+
+	return 0;
+}
+
+int msm_submitqueue_init(struct msm_file_private *ctx)
+{
+	if (!ctx)
+		return 0;
+
+	INIT_LIST_HEAD(&ctx->submitqueues);
+
+	rwlock_init(&ctx->queuelock);
+
+	return msm_submitqueue_create(ctx, 2, 0, NULL);
+}
+
+int msm_submitqueue_remove(struct msm_file_private *ctx, u32 id)
+{
+	struct msm_gpu_submitqueue *entry;
+
+	if (!ctx)
+		return 0;
+
+	/*
+	 * id 0 is the "default" queue and can't be destroyed
+	 * by the user
+	 */
+	if (!id)
+		return -ENOENT;
+
+	write_lock(&ctx->queuelock);
+
+	list_for_each_entry(entry, &ctx->submitqueues, node) {
+		if (entry->id == id) {
+			list_del(&entry->node);
+			write_unlock(&ctx->queuelock);
+
+			msm_submitqueue_put(entry);
+			return 0;
+		}
+	}
+
+	write_unlock(&ctx->queuelock);
+	return -ENOENT;
+}
+