drm: Add the TTM GPU memory manager subsystem.

TTM is a GPU memory manager subsystem designed for use with GPU
devices with various memory types (On-card VRAM, AGP,
PCI apertures etc.). It's essentially a helper library that assists
the DRM driver in creating and managing persistent buffer objects.

TTM manages placement of data and CPU map setup and teardown on
data movement. It can also optionally manage synchronization of
data on a per-buffer-object level.

TTM takes care to provide an always valid virtual user-space address
to a buffer object which makes user-space sub-allocation of
big buffer objects feasible.

TTM uses a fine-grained per buffer-object locking scheme, taking
care to release all relevant locks when waiting for the GPU.
Although this implies some locking overhead, it's probably a big
win for devices with multiple command submission mechanisms, since
the lock contention will be minimal.

TTM can be used with whatever user-space interface the driver
chooses, including GEM. It's used by the upcoming Radeon KMS DRM driver
and is also the GPU memory management core of various new experimental
DRM drivers.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 153 insertions, 0 deletions

diff --git a/include/drm/ttm/ttm_memory.h b/include/drm/ttm/ttm_memory.h
new file mode 100644
index 00000000000..d8b8f042c4f
--- /dev/null
+++ b/include/drm/ttm/ttm_memory.h
@@ -0,0 +1,153 @@
+/**************************************************************************
+ *
+ * Copyright (c) 2006-2009 VMware, Inc., Palo Alto, CA., USA
+ * All Rights Reserved.
+ *
+ * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS 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.
+ *
+ **************************************************************************/
+
+#ifndef TTM_MEMORY_H
+#define TTM_MEMORY_H
+
+#include <linux/workqueue.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+#include <linux/errno.h>
+
+/**
+ * struct ttm_mem_shrink - callback to shrink TTM memory usage.
+ *
+ * @do_shrink: The callback function.
+ *
+ * Arguments to the do_shrink functions are intended to be passed using
+ * inheritance. That is, the argument class derives from struct ttm_mem_srink,
+ * and can be accessed using container_of().
+ */
+
+struct ttm_mem_shrink {
+	int (*do_shrink) (struct ttm_mem_shrink *);
+};
+
+/**
+ * struct ttm_mem_global - Global memory accounting structure.
+ *
+ * @shrink: A single callback to shrink TTM memory usage. Extend this
+ * to a linked list to be able to handle multiple callbacks when needed.
+ * @swap_queue: A workqueue to handle shrinking in low memory situations. We
+ * need a separate workqueue since it will spend a lot of time waiting
+ * for the GPU, and this will otherwise block other workqueue tasks(?)
+ * At this point we use only a single-threaded workqueue.
+ * @work: The workqueue callback for the shrink queue.
+ * @queue: Wait queue for processes suspended waiting for memory.
+ * @lock: Lock to protect the @shrink - and the memory accounting members,
+ * that is, essentially the whole structure with some exceptions.
+ * @emer_memory: Lowmem memory limit available for root.
+ * @max_memory: Lowmem memory limit available for non-root.
+ * @swap_limit: Lowmem memory limit where the shrink workqueue kicks in.
+ * @used_memory: Currently used lowmem memory.
+ * @used_total_memory: Currently used total (lowmem + highmem) memory.
+ * @total_memory_swap_limit: Total memory limit where the shrink workqueue
+ * kicks in.
+ * @max_total_memory: Total memory available to non-root processes.
+ * @emer_total_memory: Total memory available to root processes.
+ *
+ * Note that this structure is not per device. It should be global for all
+ * graphics devices.
+ */
+
+struct ttm_mem_global {
+	struct ttm_mem_shrink *shrink;
+	struct workqueue_struct *swap_queue;
+	struct work_struct work;
+	wait_queue_head_t queue;
+	spinlock_t lock;
+	uint64_t emer_memory;
+	uint64_t max_memory;
+	uint64_t swap_limit;
+	uint64_t used_memory;
+	uint64_t used_total_memory;
+	uint64_t total_memory_swap_limit;
+	uint64_t max_total_memory;
+	uint64_t emer_total_memory;
+};
+
+/**
+ * ttm_mem_init_shrink - initialize a struct ttm_mem_shrink object
+ *
+ * @shrink: The object to initialize.
+ * @func: The callback function.
+ */
+
+static inline void ttm_mem_init_shrink(struct ttm_mem_shrink *shrink,
+				       int (*func) (struct ttm_mem_shrink *))
+{
+	shrink->do_shrink = func;
+}
+
+/**
+ * ttm_mem_register_shrink - register a struct ttm_mem_shrink object.
+ *
+ * @glob: The struct ttm_mem_global object to register with.
+ * @shrink: An initialized struct ttm_mem_shrink object to register.
+ *
+ * Returns:
+ * -EBUSY: There's already a callback registered. (May change).
+ */
+
+static inline int ttm_mem_register_shrink(struct ttm_mem_global *glob,
+					  struct ttm_mem_shrink *shrink)
+{
+	spin_lock(&glob->lock);
+	if (glob->shrink != NULL) {
+		spin_unlock(&glob->lock);
+		return -EBUSY;
+	}
+	glob->shrink = shrink;
+	spin_unlock(&glob->lock);
+	return 0;
+}
+
+/**
+ * ttm_mem_unregister_shrink - unregister a struct ttm_mem_shrink object.
+ *
+ * @glob: The struct ttm_mem_global object to unregister from.
+ * @shrink: A previously registert struct ttm_mem_shrink object.
+ *
+ */
+
+static inline void ttm_mem_unregister_shrink(struct ttm_mem_global *glob,
+					     struct ttm_mem_shrink *shrink)
+{
+	spin_lock(&glob->lock);
+	BUG_ON(glob->shrink != shrink);
+	glob->shrink = NULL;
+	spin_unlock(&glob->lock);
+}
+
+extern int ttm_mem_global_init(struct ttm_mem_global *glob);
+extern void ttm_mem_global_release(struct ttm_mem_global *glob);
+extern int ttm_mem_global_alloc(struct ttm_mem_global *glob, uint64_t memory,
+				bool no_wait, bool interruptible, bool himem);
+extern void ttm_mem_global_free(struct ttm_mem_global *glob,
+				uint64_t amount, bool himem);
+extern size_t ttm_round_pot(size_t size);
+#endif