/*
* Copyright © 2008-2015 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.
*/
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
/**
* DOC: fence register handling
*
* Important to avoid confusions: "fences" in the i915 driver are not execution
* fences used to track command completion but hardware detiler objects which
* wrap a given range of the global GTT. Each platform has only a fairly limited
* set of these objects.
*
* Fences are used to detile GTT memory mappings. They're also connected to the
* hardware frontbuffer render tracking and hence interract with frontbuffer
* conmpression. Furthermore on older platforms fences are required for tiled
* objects used by the display engine. They can also be used by the render
* engine - they're required for blitter commands and are optional for render
* commands. But on gen4+ both display (with the exception of fbc) and rendering
* have their own tiling state bits and don't need fences.
*
* Also note that fences only support X and Y tiling and hence can't be used for
* the fancier new tiling formats like W, Ys and Yf.
*
* Finally note that because fences are such a restricted resource they're
* dynamically associated with objects. Furthermore fence state is committed to
* the hardware lazily to avoid unecessary stalls on gen2/3. Therefore code must
* explictly call i915_gem_object_get_fence() to synchronize fencing status
* for cpu access. Also note that some code wants an unfenced view, for those
* cases the fence can be removed forcefully with i915_gem_object_put_fence().
*
* Internally these functions will synchronize with userspace access by removing
* CPU ptes into GTT mmaps (not the GTT ptes themselves) as needed.
*/
static void i965_write_fence_reg(struct drm_device *dev, int reg,
struct drm_i915_gem_object *obj)
{
struct drm_i915_private *dev_priv = dev->dev_private;
int fence_reg;
int fence_pitch_shift;
if (INTEL_INFO(dev)->gen >= 6) {
fence_reg = FENCE_REG_SANDYBRIDGE_0;
fence_pitch_shift = SANDYBRIDGE_FENCE_PITCH_SHIFT;
} else {
fence_reg = FENCE_REG_965_0;
fence_pitch_shift = I965_FENCE_PITCH_SHIFT;
}
fence_reg += reg * 8;
/* To w/a incoherency with non-atomic 64-bit register updates,
* we split the 64-bit update into two 32-bit writes. In order
* for a partial fence not to be evaluated between writes, we
* precede the update with write to turn off the fence register,
* and only enable the fence as the last step.
*
* For extra levels of paranoia, we make sure each step lands
* before applying the next step.
*/
I915_WRITE(fence_reg, 0);
POSTING_READ(fence_reg);
if (obj) {
u32 size = i915_gem_obj_ggtt_size(obj);
uint64_t val;
/* Adjust fence size to match tiled area */
if (obj->tiling_mode != I915_TILING_NONE) {
uint32_t row_size = obj->stride *
(obj->tiling_mode == I915_TILING_Y ? 32 : 8);
size = (size / row_size) * row_size;
}
val = (uint64_t)((i915_gem_obj_ggtt_offset(obj) + size - 4096) &
0xfffff000) << 32;
val |= i915_gem_obj_ggtt_offset(obj) & 0xfffff000;
val |= (uint64_t)((obj->stride / 128) - 1) << fence_pitch_shift;
if (obj->tiling_mode == I915_TILING_Y)
val |= 1 << I965_FENCE_TILING_Y_SHIFT;
val |= I965_FENCE_REG_VALID;
I915_WRITE(fence_reg + 4, val >> 32);
POSTING_READ(fence_reg + 4);
I915_WRITE(fence_reg + 0, val);
POSTING_READ(fence_reg);
} else {
I915_WRITE(fence_reg + 4, 0);
POSTING_READ(fence_reg + 4);
}
}
static void i915_write_fence_reg(struct drm_device *dev, int reg,
struct drm_i915_gem_object *obj)
{
struct drm_i915_private *dev_priv = dev->dev_private;
u32 val;
if (obj) {
u32 size = i915_gem_obj_ggtt_size(obj);
int pitch_val;
int tile_width;
WARN((i915_gem_obj_ggtt_offset(obj) & ~I915_FENCE_START_MASK) ||
(size & -size) != size ||
(i915_gem_obj_ggtt_offset(obj) & (size - 1)),
"object 0x%08lx [fenceable? %d] not 1M or pot-size (0x%08x) aligned\n",
i915_gem_obj_ggtt_offset(obj), obj->map_and_fenceable, size);
if (obj->tiling_mode == I915_TILING_Y && HAS_128_BYTE_Y_TILING(dev))
tile_width = 128;
else
tile_width = 512;
/* Note: pitch better be a power of two tile widths */
pitch_val = obj->stride / tile_width;
pitch_val = ffs(pitch_val) - 1;
val = i915_gem_obj_ggtt_offset(obj);
if (obj->tiling_mode == I915_TILING_Y)
val |= 1 << I830_FENCE_TILING_Y_SHIFT;
val |= I915_FENCE_SIZE_BITS(size);
val |= pitch_val << I830_FENCE_PITCH_SHIFT;
val |= I830_FENCE_REG_VALID;
} else
val = 0;
if (reg < 8)
reg = FENCE_REG_830_0 + reg * 4;
else
reg = FENCE_REG_945_8 + (reg - 8) * 4;
I915_WRITE(reg, val);
POSTING_READ(reg);
}
static void i830_write_fence_reg(struct drm_device *dev, int reg,
struct drm_i915_gem_object *obj)
{
struct drm_i915_private *dev_priv = dev->dev_private;
uint32_t val;
if (obj) {
u32 size = i915_gem_obj_ggtt_size(obj);
uint32_t pitch_val;
WARN((i915_gem_obj_ggtt_offset(obj) & ~I830_FENCE_START_MASK) ||
(size & -size) != size ||
(i915_gem_obj_ggtt_offset(obj) & (size - 1)),
"object 0x%08lx not 512K or pot-size 0x%08x aligned\n",
i915_gem_obj_ggtt_offset(obj), size);
pitch_val = obj->stride / 128;
pitch_val = ffs(pitch_val) - 1;
val = i915_gem_obj_ggtt_offset(obj);
if (obj->tiling_mode == I915_TILING_Y)
val |= 1 << I830_FENCE_TILING_Y_SHIFT;
val |= I830_FENCE_SIZE_BITS(size);
val |= pitch_val << I830_FENCE_PITCH_SHIFT;
val |= I830_FENCE_REG_VALID;
} else
val = 0;
I915_WRITE(FENCE_REG_830_0 + reg * 4, val);
POSTING_READ(FENCE_REG_830_0 + reg * 4);
}
inline static bool i915_gem_object_needs_mb(struct drm_i915_gem_object *obj)
{
return obj && obj->base.read_domains & I915_GEM_DOMAIN_GTT;
}
static void i915_gem_write_fence(struct drm_device *dev, int reg,
struct drm_i915_gem_object *obj)
{
struct drm_i915_private *dev_priv = dev->dev_private;
/* Ensure that all CPU reads are completed before installing a fence
* and all writes before removing the fence.
*/
if (i915_gem_object_needs_mb(dev_priv->fence_regs[reg].obj))
mb();
WARN(obj && (!obj->stride || !obj->tiling_mode),
"bogus fence setup with stride: 0x%x, tiling mode: %i\n",
obj->stride, obj->tiling_mode);
if (IS_GEN2(dev))
i830_write_fence_reg(dev, reg, obj);
else if (IS_GEN3(dev))
i915_write_fence_reg(dev, reg, obj);
else if (INTEL_INFO(dev)->gen >= 4)
i965_write_fence_reg(dev, reg, obj);
/* And similarly be paranoid that no direct access to this region
* is reordered to before the fence is installed.
*/
if (i915_gem_object_needs_mb(obj))
mb();
}
static inline int fence_number(struct drm_i915_private *dev_priv,
struct drm_i915_fence_reg *fence)
{
return fence - dev_priv->fence_regs;
}
static void i915_gem_object_update_fence(struct drm_i915_gem_object *obj,
struct drm_i915_fence_reg *fence,
bool enable)
{
struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
int reg = fence_number(dev_priv, fence);
i915_gem_write_fence(obj->base.dev, reg, enable ? obj : NULL);
if (enable) {
obj->fence_reg = reg;
fence->obj = obj;
list_move_tail(&fence->lru_list, &dev_priv->mm.fence_list);
} else {
obj->fence_reg = I915_FENCE_REG_NONE;
fence->obj = NULL;
list_del_init(&fence->lru_list);
}
obj->fence_dirty = false;
}
static inline void i915_gem_object_fence_lost(struct drm_i915_gem_object *obj)
{
if (obj->tiling_mode)
i915_gem_release_mmap(obj);
/* As we do not have an associated fence register, we will force
* a tiling change if we ever need to acquire one.
*/
obj->fence_dirty = false;
obj->fence_reg = I915_FENCE_REG_NONE;
}
static int
i915_gem_object_wait_fence(struct drm_i915_gem_object *obj)
{
if (obj->last_fenced_req) {
int ret = i915_wait_request(obj->last_fenced_req);
if (ret)
return ret;
i915_gem_request_assign(&obj->last_fenced_req, NULL);
}
return 0;
}
/**
* i915_gem_object_put_fence - force-remove fence for an object
* @obj: object to map through a fence reg
*
* This function force-removes any fence from the given object, which is useful
* if the kernel wants to do untiled GTT access.
*
* Returns:
*
* 0 on success, negative error code on failure.
*/
int
i915_gem_object_put_fence(struct drm_i915_gem_object *obj)
{
struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
struct drm_i915_fence_reg *fence;
int ret;
ret = i915_gem_object_wait_fence(obj);
if (ret)
return ret;
if (obj->fence_reg == I915_FENCE_REG_NONE)
return 0;
fence = &dev_priv->fence_regs[obj->fence_reg];
if (WARN_ON(fence->pin_count))
return -EBUSY;
i915_gem_object_fence_lost(obj);
i915_gem_object_update_fence(obj, fence, false);
return 0;
}
static struct drm_i915_fence_reg *
i915_find_fence_reg(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
struct drm_i915_fence_reg *reg, *avail;
int i;
/* First try to find a free reg */
avail = NULL;
for (i = dev_priv->fence_reg_start; i < dev_priv->num_fence_regs; i++) {
reg = &dev_priv->fence_regs[i];
if (!reg->obj)
return reg;
if (!reg->pin_count)
avail = reg;
}
if (avail == NULL)
goto deadlock;
/* None available, try to steal one or wait for a user to finish */
list_for_each_entry(reg, &dev_priv->mm.fence_list, lru_list) {
if (reg->pin_count)
continue;
return reg;
}
deadlock:
/* Wait for completion of pending flips which consume fences */
if (intel_has_pending_fb_unpin(dev))
return ERR_PTR(-EAGAIN);
return ERR_PTR(-EDEADLK);
}
/**
* i915_gem_object_get_fence - set up fencing for an object
* @obj: object to map through a fence reg
*
* When mapping objects through the GTT, userspace wants to be able to write
* to them without having to worry about swizzling if the object is tiled.
* This function walks the fence regs looking for a free one for @obj,
* stealing one if it can't find any.
*
* It then sets up the reg based on the object's properties: address, pitch
* and tiling format.
*
* For an untiled surface, this removes any existing fence.
*
* Returns:
*
* 0 on success, negative error code on failure.
*/
int
i915_gem_object_get_fence(struct drm_i915_gem_object *obj)
{
struct drm_device *dev = obj->base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;
bool enable = obj->tiling_mode != I915_TILING_NONE;
struct drm_i915_fence_reg *reg;
int ret;
/* Have we updated the tiling parameters upon the object and so
* will need to serialise the write to the associated fence register?
*/
if (obj->fence_dirty) {
ret = i915_gem_object_wait_fence(obj);
if (ret)
return ret;
}
/* Just update our place in the LRU if our fence is getting reused. */
if (obj->fence_reg != I915_FENCE_REG_NONE) {
reg = &dev_priv->fence_regs[obj->fence_reg];
if (!obj->fence_dirty) {
list_move_tail(®->lru_list,
&dev_priv->mm.fence_list);
return 0;
}
} else if (enable) {
if (WARN_ON(!obj->map_and_fenceable))
return -EINVAL;
reg = i915_find_fence_reg(dev);
if (IS_ERR(reg))
return PTR_ERR(reg);
if (reg->obj) {
struct drm_i915_gem_object *old = reg->obj;
ret = i915_gem_object_wait_fence(old);
if (ret)
return ret;
i915_gem_object_fence_lost(old);
}
} else
return 0;
i915_gem_object_update_fence(obj, reg, enable);
return 0;
}
/**
* i915_gem_object_pin_fence - pin fencing state
* @obj: object to pin fencing for
*
* This pins the fencing state (whether tiled or untiled) to make sure the
* object is ready to be used as a scanout target. Fencing status must be
* synchronize first by calling i915_gem_object_get_fence():
*
* The resulting fence pin reference must be released again with
* i915_gem_object_unpin_fence().
*
* Returns:
*
* True if the object has a fence, false otherwise.
*/
bool
i915_gem_object_pin_fence(struct drm_i915_gem_object *obj)
{
if (obj->fence_reg != I915_FENCE_REG_NONE) {
struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
struct i915_vma *ggtt_vma = i915_gem_obj_to_ggtt(obj);
WARN_ON(!ggtt_vma ||
dev_priv->fence_regs[obj->fence_reg].pin_count >
ggtt_vma->pin_count);
dev_priv->fence_regs[obj->fence_reg].pin_count++;
return true;
} else
return false;
}
/**
* i915_gem_object_unpin_fence - unpin fencing state
* @obj: object to unpin fencing for
*
* This releases the fence pin reference acquired through
* i915_gem_object_pin_fence. It will handle both objects with and without an
* attached fence correctly, callers do not need to distinguish this.
*/
void
i915_gem_object_unpin_fence(struct drm_i915_gem_object *obj)
{
if (obj->fence_reg != I915_FENCE_REG_NONE) {
struct drm_i915_private *dev_priv = obj->base.dev->dev_private;
WARN_ON(dev_priv->fence_regs[obj->fence_reg].pin_count <= 0);
dev_priv->fence_regs[obj->fence_reg].pin_count--;
}
}
/**
* i915_gem_restore_fences - restore fence state
* @dev: DRM device
*
* Restore the hw fence state to match the software tracking again, to be called
* after a gpu reset and on resume.
*/
void i915_gem_restore_fences(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
int i;
for (i = 0; i < dev_priv->num_fence_regs; i++) {
struct drm_i915_fence_reg *reg = &dev_priv->fence_regs[i];
/*
* Commit delayed tiling changes if we have an object still
* attached to the fence, otherwise just clear the fence.
*/
if (reg->obj) {
i915_gem_object_update_fence(reg->obj, reg,
reg->obj->tiling_mode);
} else {
i915_gem_write_fence(dev, i, NULL);
}
}
}
