linux/drivers/gpu/drm/i915/i915_gem_tiling.c

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/*
* Copyright © 2008 Intel Corporation
*
* 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 AUTHORS OR COPYRIGHT HOLDERS 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:
* Eric Anholt <eric@anholt.net>
*
*/
#include <linux/string.h>
#include <linux/bitops.h>
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
/**
* DOC: buffer object tiling
*
* i915_gem_set_tiling() and i915_gem_get_tiling() is the userspace interface to
* declare fence register requirements.
*
* In principle GEM doesn't care at all about the internal data layout of an
* object, and hence it also doesn't care about tiling or swizzling. There's two
* exceptions:
*
* - For X and Y tiling the hardware provides detilers for CPU access, so called
* fences. Since there's only a limited amount of them the kernel must manage
* these, and therefore userspace must tell the kernel the object tiling if it
* wants to use fences for detiling.
* - On gen3 and gen4 platforms have a swizzling pattern for tiled objects which
* depends upon the physical page frame number. When swapping such objects the
* page frame number might change and the kernel must be able to fix this up
* and hence now the tiling. Note that on a subset of platforms with
* asymmetric memory channel population the swizzling pattern changes in an
* unknown way, and for those the kernel simply forbids swapping completely.
*
* Since neither of this applies for new tiling layouts on modern platforms like
* W, Ys and Yf tiling GEM only allows object tiling to be set to X or Y tiled.
* Anything else can be handled in userspace entirely without the kernel's
* invovlement.
*/
/* Check pitch constriants for all chips & tiling formats */
static bool
i915_tiling_ok(struct drm_device *dev, int stride, int size, int tiling_mode)
{
int tile_width;
/* Linear is always fine */
if (tiling_mode == I915_TILING_NONE)
return true;
if (tiling_mode > I915_TILING_LAST)
return false;
if (IS_GEN2(dev) ||
(tiling_mode == I915_TILING_Y && HAS_128_BYTE_Y_TILING(dev)))
tile_width = 128;
else
tile_width = 512;
/* check maximum stride & object size */
/* i965+ stores the end address of the gtt mapping in the fence
* reg, so dont bother to check the size */
if (INTEL_INFO(dev)->gen >= 7) {
if (stride / 128 > GEN7_FENCE_MAX_PITCH_VAL)
return false;
} else if (INTEL_INFO(dev)->gen >= 4) {
if (stride / 128 > I965_FENCE_MAX_PITCH_VAL)
return false;
} else {
if (stride > 8192)
return false;
if (IS_GEN3(dev)) {
if (size > I830_FENCE_MAX_SIZE_VAL << 20)
return false;
} else {
if (size > I830_FENCE_MAX_SIZE_VAL << 19)
return false;
}
}
if (stride < tile_width)
return false;
/* 965+ just needs multiples of tile width */
if (INTEL_INFO(dev)->gen >= 4) {
if (stride & (tile_width - 1))
return false;
return true;
}
/* Pre-965 needs power of two tile widths */
if (stride & (stride - 1))
return false;
return true;
}
/* Is the current GTT allocation valid for the change in tiling? */
static bool
i915_gem_object_fence_ok(struct drm_i915_gem_object *obj, int tiling_mode)
{
struct drm_i915_private *dev_priv = to_i915(obj->base.dev);
u32 size;
if (tiling_mode == I915_TILING_NONE)
return true;
if (INTEL_GEN(dev_priv) >= 4)
return true;
if (IS_GEN3(dev_priv)) {
if (i915_gem_obj_ggtt_offset(obj) & ~I915_FENCE_START_MASK)
return false;
} else {
if (i915_gem_obj_ggtt_offset(obj) & ~I830_FENCE_START_MASK)
return false;
}
size = i915_gem_get_ggtt_size(dev_priv, obj->base.size, tiling_mode);
if (i915_gem_obj_ggtt_size(obj) != size)
return false;
if (i915_gem_obj_ggtt_offset(obj) & (size - 1))
return false;
return true;
}
/**
* i915_gem_set_tiling - IOCTL handler to set tiling mode
* @dev: DRM device
* @data: data pointer for the ioctl
* @file: DRM file for the ioctl call
*
* Sets the tiling mode of an object, returning the required swizzling of
* bit 6 of addresses in the object.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int
i915_gem_set_tiling(struct drm_device *dev, void *data,
struct drm_file *file)
{
struct drm_i915_gem_set_tiling *args = data;
struct drm_i915_private *dev_priv = to_i915(dev);
struct drm_i915_gem_object *obj;
int ret = 0;
/* Make sure we don't cross-contaminate obj->tiling_and_stride */
BUILD_BUG_ON(I915_TILING_LAST & STRIDE_MASK);
obj = i915_gem_object_lookup(file, args->handle);
if (!obj)
return -ENOENT;
if (!i915_tiling_ok(dev,
args->stride, obj->base.size, args->tiling_mode)) {
i915_gem_object_put_unlocked(obj);
return -EINVAL;
}
intel_runtime_pm_get(dev_priv);
mutex_lock(&dev->struct_mutex);
if (obj->pin_display || obj->framebuffer_references) {
ret = -EBUSY;
goto err;
}
if (args->tiling_mode == I915_TILING_NONE) {
args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
args->stride = 0;
} else {
if (args->tiling_mode == I915_TILING_X)
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_x;
else
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_y;
/* Hide bit 17 swizzling from the user. This prevents old Mesa
* from aborting the application on sw fallbacks to bit 17,
* and we use the pread/pwrite bit17 paths to swizzle for it.
* If there was a user that was relying on the swizzle
* information for drm_intel_bo_map()ed reads/writes this would
* break it, but we don't have any of those.
*/
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
/* If we can't handle the swizzling, make it untiled. */
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_UNKNOWN) {
args->tiling_mode = I915_TILING_NONE;
args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
args->stride = 0;
}
}
if (args->tiling_mode != i915_gem_object_get_tiling(obj) ||
args->stride != i915_gem_object_get_stride(obj)) {
/* We need to rebind the object if its current allocation
* no longer meets the alignment restrictions for its new
* tiling mode. Otherwise we can just leave it alone, but
* need to ensure that any fence register is updated before
* the next fenced (either through the GTT or by the BLT unit
* on older GPUs) access.
*
* After updating the tiling parameters, we then flag whether
* we need to update an associated fence register. Note this
* has to also include the unfenced register the GPU uses
* whilst executing a fenced command for an untiled object.
*/
drm/i915: Fix obj->map_and_fenceable across tiling changes As obj->map_and_fenceable computation has changed to only be set when the object is bound inside the global GTT (and is suitable aligned to a fence region) we need to accommodate those changes when the tiling is adjusted. The easiest solution is to unbind from the global GTT if we are currently fenceable, but will not be after the tiling change. The bug has been exposed by commit f8fcadba218fe6d23b2e353fea1cf0a4be4c9454 Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Fri Oct 31 13:53:52 2014 +0000 drm/i915: Only mark as map-and-fenceable when bound into the GGTT which tried to fix an oversight from commit e6a844687cf929ec053c7578d5ecc794a8a6c5cf Author: Chris Wilson <chris@chris-wilson.co.uk> Date: Mon Aug 11 12:00:12 2014 +0200 drm/i915: Force CPU relocations if not GTT mapped which changed the handling of obj->map_and_fenceable. Note that the alignment check is a vestige from our attempts to reduce the alignment requirements of tiled but unfenced buffers on gen2/3. Also, that was when unbinding from the GTT meant UC writes and clflushing, so we went to great pains to avoid such. That leaves the actual bug of setting map_and_fenceable to true if we're not bound to ggtt, which violates the change introduced in the above patch. Unbinding in that case really looks like the simplest and safest option, we have to do it anyway. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=85896 Testcase: igt/gem_concurrent_blit/gttX* Tested-by: huax.lu@intel.com Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Tested-by: Valtteri Rantala <valtteri.rantala@intel.com> [Jani: amend commit message per input from Daniel and bisect result from Valtteri] Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2014-11-06 08:40:35 +00:00
if (obj->map_and_fenceable &&
!i915_gem_object_fence_ok(obj, args->tiling_mode))
ret = i915_vma_unbind(i915_gem_obj_to_ggtt(obj));
if (ret == 0) {
if (obj->pages &&
obj->madv == I915_MADV_WILLNEED &&
dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
if (args->tiling_mode == I915_TILING_NONE)
i915_gem_object_unpin_pages(obj);
if (!i915_gem_object_is_tiled(obj))
i915_gem_object_pin_pages(obj);
}
obj->fence_dirty =
!i915_gem_active_is_idle(&obj->last_fence,
&dev->struct_mutex) ||
obj->fence_reg != I915_FENCE_REG_NONE;
obj->tiling_and_stride =
args->stride | args->tiling_mode;
/* Force the fence to be reacquired for GTT access */
i915_gem_release_mmap(obj);
}
}
/* we have to maintain this existing ABI... */
args->stride = i915_gem_object_get_stride(obj);
args->tiling_mode = i915_gem_object_get_tiling(obj);
/* Try to preallocate memory required to save swizzling on put-pages */
if (i915_gem_object_needs_bit17_swizzle(obj)) {
if (obj->bit_17 == NULL) {
obj->bit_17 = kcalloc(BITS_TO_LONGS(obj->base.size >> PAGE_SHIFT),
sizeof(long), GFP_KERNEL);
}
} else {
kfree(obj->bit_17);
obj->bit_17 = NULL;
}
err:
i915_gem_object_put(obj);
mutex_unlock(&dev->struct_mutex);
intel_runtime_pm_put(dev_priv);
return ret;
}
/**
* i915_gem_get_tiling - IOCTL handler to get tiling mode
* @dev: DRM device
* @data: data pointer for the ioctl
* @file: DRM file for the ioctl call
*
* Returns the current tiling mode and required bit 6 swizzling for the object.
*
* Called by the user via ioctl.
*
* Returns:
* Zero on success, negative errno on failure.
*/
int
i915_gem_get_tiling(struct drm_device *dev, void *data,
struct drm_file *file)
{
struct drm_i915_gem_get_tiling *args = data;
struct drm_i915_private *dev_priv = to_i915(dev);
struct drm_i915_gem_object *obj;
obj = i915_gem_object_lookup(file, args->handle);
if (!obj)
return -ENOENT;
args->tiling_mode = READ_ONCE(obj->tiling_and_stride) & TILING_MASK;
switch (args->tiling_mode) {
case I915_TILING_X:
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_x;
break;
case I915_TILING_Y:
args->swizzle_mode = dev_priv->mm.bit_6_swizzle_y;
break;
case I915_TILING_NONE:
args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
break;
default:
DRM_ERROR("unknown tiling mode\n");
}
/* Hide bit 17 from the user -- see comment in i915_gem_set_tiling */
if (dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES)
args->phys_swizzle_mode = I915_BIT_6_SWIZZLE_UNKNOWN;
else
args->phys_swizzle_mode = args->swizzle_mode;
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
i915_gem_object_put_unlocked(obj);
return 0;
}