path: root/drivers/gpu/drm/nouveau/nouveau_object.c

/*
 * Copyright (C) 2006 Ben Skeggs.
 *
 * 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, sublicense, 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 NONINFRINGEMENT.
 * IN NO EVENT SHALL THE COPYRIGHT OWNER(S) 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.
 *
 */

/*
 * Authors:
 *   Ben Skeggs <darktama@iinet.net.au>
 */

#include "drmP.h"
#include "drm.h"
#include "nouveau_drv.h"
#include "nouveau_drm.h"

/* NVidia uses context objects to drive drawing operations.

   Context objects can be selected into 8 subchannels in the FIFO,
   and then used via DMA command buffers.

   A context object is referenced by a user defined handle (CARD32). The HW
   looks up graphics objects in a hash table in the instance RAM.

   An entry in the hash table consists of 2 CARD32. The first CARD32 contains
   the handle, the second one a bitfield, that contains the address of the
   object in instance RAM.

   The format of the second CARD32 seems to be:

   NV4 to NV30:

   15: 0  instance_addr >> 4
   17:16  engine (here uses 1 = graphics)
   28:24  channel id (here uses 0)
   31	  valid (use 1)

   NV40:

   15: 0  instance_addr >> 4   (maybe 19-0)
   21:20  engine (here uses 1 = graphics)
   I'm unsure about the other bits, but using 0 seems to work.

   The key into the hash table depends on the object handle and channel id and
   is given as:
*/
static uint32_t
nouveau_ramht_hash_handle(struct drm_device *dev, int channel, uint32_t handle)
{
	struct drm_nouveau_private *dev_priv = dev->dev_private;
	uint32_t hash = 0;
	int i;

	NV_DEBUG(dev, "ch%d handle=0x%08x\n", channel, handle);

	for (i = 32; i > 0; i -= dev_priv->ramht_bits) {
		hash ^= (handle & ((1 << dev_priv->ramht_bits) - 1));
		handle >>= dev_priv->ramht_bits;
	}

	if (dev_priv->card_type < NV_50)
		hash ^= channel << (dev_priv->ramht_bits - 4);
	hash <<= 3;

	NV_DEBUG(dev, "hash=0x%08x\n", hash);
	return hash;
}

static int
nouveau_ramht_entry_valid(struct drm_device *dev, struct nouveau_gpuobj *ramht,
			  uint32_t offset)
{
	struct drm_nouveau_private *dev_priv = dev->dev_private;
	uint32_t ctx = nv_ro32(dev, ramht, (offset + 4)/4);

	if (dev_priv->card_type < NV_40)
		return ((ctx & NV_RAMHT_CONTEXT_VALID) != 0);
	return (ctx != 0);
}

static int
nouveau_ramht_insert(struct drm_device *dev, struct nouveau_gpuobj_ref *ref)
{
	st