/*
* 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 interact with frontbuffer
* compression. 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 unnecessary stalls on gen2/3. Therefore code must
* explicitly 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.
*/
#define pipelined 0
static void i965_write_fence_reg(struct drm_i915_fence_reg *fence,
struct i915_vma *vma)
{
i915_reg_t fence_reg_lo, fence_reg_hi;
int fence_pitch_shift;
u64 val;
if (INTEL_INFO(fence->i915)->gen >= 6) {
fence_reg_lo = FENCE_REG_GEN6_LO(fence->id);
fence_reg_hi = FENCE_REG_GEN6_HI(fence->id);
fence_pitch_shift = GEN6_FENCE_PITCH_SHIFT;
} else {
fence_reg_lo = FENCE_REG_965_LO(fence->id);
fence_reg_hi = FENCE_REG_965_HI(fence->id);
fence_pitch_shift = I965_FENCE_PITCH_SHIFT;
}
val = 0;
if (vma) {
unsigned int tiling = i915_gem_object_get_tiling(vma->obj);
bool is_y_tiled = tiling == I915_TILING_Y;
unsigned int stride = i915_gem_object_get_stride(vma->obj);
u32 row_size = stride * (is_y_tiled ? 32 : 8);
u32 size = rounddown((u32)vma->node.size, row_size);
val = ((vma->node.start + size - 4096) & 0xfffff000) << 32;
val |= vma->node.start & 0xfffff000;
val |= (u64)((stride / 128) - 1) << fence_pitch_shift;
if (is_y_tiled)
val |= BIT(I965_FENCE_TILING_Y_SHIFT);
val |= I965_FENCE_REG_VALID;
}
if (!pipelined) {
struct drm_i915_private *dev_priv = fence->i915;
/* 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_lo, 0);
POSTING_READ(fence_reg_lo);
I915_WRITE(fence_reg_hi, upper_32_bits(val));
I915_WRITE(fence_reg_lo, lower_32_bits(val));
POSTING_READ(fence_reg_lo);
}
}
static void i915_write_fence_reg(struct drm_i915_fence_reg *fence,
struct i915_vma *vma)
{
u32 val;
val = 0;
if (vma) {
unsigned int tiling = i915_gem_object_get_tiling(vma->obj);
bool is_y_tiled = tiling == I915_TILING_Y;
unsigned int stride = i915_gem_object_get_stride(vma->obj);
int pitch_val;
int tile_width;
WARN((vma->node.start & ~I915_FENCE_START_MASK) ||
!is_power_of_2(vma->node.size) ||
(vma->node.start & (vma->node.size - 1)),
"object 0x%08llx [fenceable? %d] not 1M or pot-size (0x%08llx) aligned\n",
vma->node.start,
i915_vma_is_map_and_fenceable(vma),
vma->node.size);
if (is_y_tiled && HAS_128_BYTE_Y_TILING(fence->i915))
tile_width = 128;
else
tile_width = 512;
/* Note: pitch better be a power of two tile widths */
pitch_val = stride / tile_width;
pitch_val = ffs(pitch_val) - 1;
val = vma->node.start;
if (is_y_tiled)
val |= BIT(I830_FENCE_TILING_Y_SHIFT);
val |= I915_FENCE_SIZE_BITS(vma->node.size);
val |= pitch_val << I830_FENCE_PITCH_SHIFT;
val |= I830_FENCE_REG_VALID;
}
if (!pipelined) {
struct drm_i915_private *dev_priv = fence->i915;
i915_reg_t reg = FENCE_REG(fence->id);
I915_WRITE(reg, val);
POSTING_READ(reg);
}
}
static void i830_write_fence_reg(struct drm_i915_fence_reg *fence,
struct i915_vma *vma)
{
u32 val;
val = 0;
if (vma) {
unsigned int tiling = i915_gem_object_get_tiling(vma->obj);
bool is_y_tiled = tiling == I915_TILING_Y;
unsigned int stride = i915_gem_object_get_stride(vma->obj);
u32 pitch_val;
WARN((vma->node.start & ~I830_FENCE_START_MASK) ||
!is_power_of_2(vma->node.size) ||
(vma->node.start & (vma->node.size - 1)),
"object 0x%08llx not 512K or pot-size 0x%08llx aligned\n",
vma->node.start, vma->node.size);
pitch_val = stride / 128;
pitch_val = ffs(pitch_val) - 1;
val = vma->node.start;
if (is_y_tiled)
val |= BIT(I830_FENCE_TILING_Y_SHIFT);
val |= I830_FENCE_SIZE_BITS(vma->node.size);
val |= pitch_val << I830_FENCE_PITCH_SHIFT;
val |= I830_FENCE_REG_VALID;
}
if (!pipelined) {
struct drm_i915_private *dev_priv = fence->i915;
i915_reg_t reg = FENCE_REG(fence->id);
I915_WRITE(reg, val);
POSTING_READ(reg);
}
}
static void fence_write(struct drm_i915_fence_reg *fence,
struct i915_vma *vma)
{
/* Previous access through the fence register is marshalled by
* the mb() inside the fault handlers (i915_gem_release_mmaps)
* and explicitly managed for internal users.
*/
if (IS_GEN2(fence->i915))
i830_write_fence_reg(fence, vma);
else if (IS_GEN3(fence->i915))
i915_write_fence_reg(fence, vma);
else
i965_write_fence_reg(fence, vma);
/* Access through the fenced region afterwards is
* ordered by the posting reads whilst writing the registers.
*/
fence->dirty = false;
}
static int fence_update(struct drm_i915_fence_reg *fence,
struct i915_vma *vma)
{
int ret;
if (vma) {
if (!i915_vma_is_map_and_fenceable(vma))
return -EINVAL;
if (WARN(!i915_gem_object_get_stride(vma->obj) ||
!i915_gem_object_get_tiling(vma->obj),
"bogus fence setup with stride: 0x%x, tiling mode: %i\n",
i915_gem_object_get_stride(vma->obj),
i915_gem_object_get_tiling(vma->obj)))
return -EINVAL;
ret = i915_gem_active_retire(&vma->last_fence,
&vma->obj->base.dev->struct_mutex);
if (ret)
return ret;
}
if (fence->vma) {
ret = i915_gem_active_retire(&fence->vma->last_fence,
&fence->vma->obj->base.dev->struct_mutex);
if (ret)
return ret;
}
if (fence->vma && fence->vma != vma) {
/* Ensure that all userspace CPU access is completed before
* stealing the fence.
*/
i915_gem_release_mmap(fence->vma->obj);
fence->vma->fence = NULL;
fence->vma = NULL;
list_move(&fence->link, &fence->i915->mm.fence_list);
}
fence_write(fence, vma);
if (vma) {
if (fence->vma != vma) {
vma->fence = fence;
fence->vma = vma;
}
list_move_tail(&fence->link, &fence->i915->mm.fence_list);
}
return 0;
}
/**
* i915_vma_put_fence - force-remove fence for a VMA
* @vma: vma to map linearly (not 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_vma_put_fence(struct i915_vma *vma)
{
struct drm_i915_fence_reg *fence = vma->fence;
if (!fence)
return 0;
if (fence->pin_count)
return -EBUSY;
return fence_update(fence, NULL);
}
static struct drm_i915_fence_reg *fence_find(struct drm_i915_private *dev_priv)
{
struct drm_i915_fence_reg *fence;
list_for_each_entry(fence, &dev_priv->mm.fence_list, link) {
if (fence->pin_count)
continue;
return fence;
}
/* Wait for completion of pending flips which consume fences */
if (intel_has_pending_fb_unpin(&dev_priv->drm))
return ERR_PTR(-EAGAIN);
return ERR_PTR(-EDEADLK);
}
/**
* i915_vma_get_fence - set up fencing for a vma
* @vma: vma 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_vma_get_fence(struct i915_vma *vma)
{
struct drm_i915_fence_reg *fence;
struct i915_vma *set = i915_gem_object_is_tiled(vma->obj) ? vma : NULL;
/* Just update our place in the LRU if our fence is getting reused. */
if (vma->fence) {
fence = vma->fence;
if (!fence->dirty) {
list_move_tail(&fence->link,
&fence->i915->mm.fence_list);
return 0;
}
} else if (set) {
fence = fence_find(to_i915(vma->vm->dev));
if (IS_ERR(fence))
return PTR_ERR(fence);
} else
return 0;
return fence_update(fence, set);
}
/**
* 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 = to_i915(dev);
int i;
for (i = 0; i < dev_priv->num_fence_regs; i++) {
struct drm_i915_fence_reg *reg = &dev_priv->fence_regs[i];
struct i915_vma *vma = reg->vma;
/*
* Commit delayed tiling changes if we have an object still
* attached to the fence, otherwise just clear the fence.
*/
if (vma && !i915_gem_object_is_tiled(vma->obj))
vma = NULL;
fence_update(reg, vma);
}
}
/**
* DOC: tiling swizzling details
*
* The idea behind tiling is to increase cache hit rates by rearranging
* pixel data so that a group of pixel accesses are in the same cacheline.
* Performance improvement from doing this on the back/depth buffer are on
* the order of 30%.
*
* Intel architectures make this somewhat more complicated, though, by
* adjustments made to addressing of data when the memory is in interleaved
* mode (matched pairs of DIMMS) to improve memory bandwidth.
* For interleaved memory, the CPU sends every sequential 64 bytes
* to an alternate memory channel so it can get the bandwidth from both.
*
* The GPU also rearranges its accesses for increased bandwidth to interleaved
* memory, and it matches what the CPU does for non-tiled. However, when tiled
* it does it a little differently, since one walks addresses not just in the
* X direction but also Y. So, along with alternating channels when bit
* 6 of the address flips, it also alternates when other bits flip -- Bits 9
* (every 512 bytes, an X tile scanline) and 10 (every two X tile scanlines)
* are common to both the 915 and 965-class hardware.
*
* The CPU also sometimes XORs in higher bits as well, to improve
* bandwidth doing strided access like we do so frequently in graphics. This
* is called "Channel XOR Randomization" in the MCH documentation. The result
* is that the CPU is XORing in either bit 11 or bit 17 to bit 6 of its address
* decode.
*
* All of this bit 6 XORing has an effect on our memory management,
* as we need to make sure that the 3d driver can correctly address object
* contents.
*
* If we don't have interleaved memory, all tiling is safe and no swizzling is
* required.
*
* When bit 17 is XORed in, we simply refuse to tile at all. Bit
* 17 is not just a page offset, so as we page an object out and back in,
* individual pages in it will have different bit 17 addresses, resulting in
* each 64 bytes being swapped with its neighbor!
*
* Otherwise, if interleaved, we have to tell the 3d driver what the address
* swizzling it needs to do is, since it's writing with the CPU to the pages
* (bit 6 and potentially bit 11 XORed in), and the GPU is reading from the
* pages (bit 6, 9, and 10 XORed in), resulting in a cumulative bit swizzling
* required by the CPU of XORing in bit 6, 9, 10, and potentially 11, in order
* to match what the GPU expects.
*/
/**
* i915_gem_detect_bit_6_swizzle - detect bit 6 swizzling pattern
* @dev: DRM device
*
* Detects bit 6 swizzling of address lookup between IGD access and CPU
* access through main memory.
*/
void
i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = to_i915(dev);
uint32_t swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
uint32_t swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
if (INTEL_INFO(dev)->gen >= 8 || IS_VALLEYVIEW(dev)) {
/*
* On BDW+, swizzling is not used. We leave the CPU memory
* controller in charge of optimizing memory accesses without
* the extra address manipulation GPU side.
*
* VLV and CHV don't have GPU swizzling.
*/
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
} else if (INTEL_INFO(dev)->gen >= 6) {
if (dev_priv->preserve_bios_swizzle) {
if (I915_READ(DISP_ARB_CTL) &
DISP_TILE_SURFACE_SWIZZLING) {
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
swizzle_y = I915_BIT_6_SWIZZLE_9;
} else {
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
}
} else {
uint32_t dimm_c0, dimm_c1;
dimm_c0 = I915_READ(MAD_DIMM_C0);
dimm_c1 = I915_READ(MAD_DIMM_C1);
dimm_c0 &= MAD_DIMM_A_SIZE_MASK | MAD_DIMM_B_SIZE_MASK;
dimm_c1 &= MAD_DIMM_A_SIZE_MASK | MAD_DIMM_B_SIZE_MASK;
/* Enable swizzling when the channels are populated
* with identically sized dimms. We don't need to check
* the 3rd channel because no cpu with gpu attached
* ships in that configuration. Also, swizzling only
* makes sense for 2 channels anyway. */
if (dimm_c0 == dimm_c1) {
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
swizzle_y = I915_BIT_6_SWIZZLE_9;
} else {
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
}
}
} else if (IS_GEN5(dev)) {
/* On Ironlake whatever DRAM config, GPU always do
* same swizzling setup.
*/
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
swizzle_y = I915_BIT_6_SWIZZLE_9;
} else if (IS_GEN2(dev)) {
/* As far as we know, the 865 doesn't have these bit 6
* swizzling issues.
*/
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
} else if (IS_MOBILE(dev) || (IS_GEN3(dev) && !IS_G33(dev))) {
uint32_t dcc;
/* On 9xx chipsets, channel interleave by the CPU is
* determined by DCC. For single-channel, neither the CPU
* nor the GPU do swizzling. For dual channel interleaved,
* the GPU's interleave is bit 9 and 10 for X tiled, and bit
* 9 for Y tiled. The CPU's interleave is independent, and
* can be based on either bit 11 (haven't seen this yet) or
* bit 17 (common).
*/
dcc = I915_READ(DCC);
switch (dcc & DCC_ADDRESSING_MODE_MASK) {
case DCC_ADDRESSING_MODE_SINGLE_CHANNEL:
case DCC_ADDRESSING_MODE_DUAL_CHANNEL_ASYMMETRIC:
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
break;
case DCC_ADDRESSING_MODE_DUAL_CHANNEL_INTERLEAVED:
if (dcc & DCC_CHANNEL_XOR_DISABLE) {
/* This is the base swizzling by the GPU for
* tiled buffers.
*/
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
swizzle_y = I915_BIT_6_SWIZZLE_9;
} else if ((dcc & DCC_CHANNEL_XOR_BIT_17) == 0) {
/* Bit 11 swizzling by the CPU in addition. */
swizzle_x = I915_BIT_6_SWIZZLE_9_10_11;
swizzle_y = I915_BIT_6_SWIZZLE_9_11;
} else {
/* Bit 17 swizzling by the CPU in addition. */
swizzle_x = I915_BIT_6_SWIZZLE_9_10_17;
swizzle_y = I915_BIT_6_SWIZZLE_9_17;
}
break;
}
/* check for L-shaped memory aka modified enhanced addressing */
if (IS_GEN4(dev) &&
!(I915_READ(DCC2) & DCC2_MODIFIED_ENHANCED_DISABLE)) {
swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
}
if (dcc == 0xffffffff) {
DRM_ERROR("Couldn't read from MCHBAR. "
"Disabling tiling.\n");
swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
}
} else {
/* The 965, G33, and newer, have a very flexible memory
* configuration. It will enable dual-channel mode
* (interleaving) on as much memory as it can, and the GPU
* will additionally sometimes enable different bit 6
* swizzling for tiled objects from the CPU.
*
* Here's what I found on the G965:
* slot fill memory size swizzling
* 0A 0B 1A 1B 1-ch 2-ch
* 512 0 0 0 512 0 O
* 512 0 512 0 16 1008 X
* 512 0 0 512 16 1008 X
* 0 512 0 512 16 1008 X
* 1024 1024 1024 0 2048 1024 O
*
* We could probably detect this based on either the DRB
* matching, which was the case for the swizzling required in
* the table above, or from the 1-ch value being less than
* the minimum size of a rank.
*
* Reports indicate that the swizzling actually
* varies depending upon page placement inside the
* channels, i.e. we see swizzled pages where the
* banks of memory are paired and unswizzled on the
* uneven portion, so leave that as unknown.
*/
if (I915_READ16(C0DRB3) == I915_READ16(C1DRB3)) {
swizzle_x = I915_BIT_6_SWIZZLE_9_10;
swizzle_y = I915_BIT_6_SWIZZLE_9;
}
}
if (swizzle_x == I915_BIT_6_SWIZZLE_UNKNOWN ||
swizzle_y == I915_BIT_6_SWIZZLE_UNKNOWN) {
/* Userspace likes to explode if it sees unknown swizzling,
* so lie. We will finish the lie when reporting through
* the get-tiling-ioctl by reporting the physical swizzle
* mode as unknown instead.
*
* As we don't strictly know what the swizzling is, it may be
* bit17 dependent, and so we need to also prevent the pages
* from being moved.
*/
dev_priv->quirks |= QUIRK_PIN_SWIZZLED_PAGES;
swizzle_x = I915_BIT_6_SWIZZLE_NONE;
swizzle_y = I915_BIT_6_SWIZZLE_NONE;
}
dev_priv->mm.bit_6_swizzle_x = swizzle_x;
dev_priv->mm.bit_6_swizzle_y = swizzle_y;
}
/*
* Swap every 64 bytes of this page around, to account for it having a new
* bit 17 of its physical address and therefore being interpreted differently
* by the GPU.
*/
static void
i915_gem_swizzle_page(struct page *page)
{
char temp[64];
char *vaddr;
int i;
vaddr = kmap(page);
for (i = 0; i < PAGE_SIZE; i += 128) {
memcpy(temp, &vaddr[i], 64);
memcpy(&vaddr[i], &vaddr[i + 64], 64);
memcpy(&vaddr[i + 64], temp, 64);
}
kunmap(page);
}
/**
* i915_gem_object_do_bit_17_swizzle - fixup bit 17 swizzling
* @obj: i915 GEM buffer object
*
* This function fixes up the swizzling in case any page frame number for this
* object has changed in bit 17 since that state has been saved with
* i915_gem_object_save_bit_17_swizzle().
*
* This is called when pinning backing storage again, since the kernel is free
* to move unpinned backing storage around (either by directly moving pages or
* by swapping them out and back in again).
*/
void
i915_gem_object_do_bit_17_swizzle(struct drm_i915_gem_object *obj)
{
struct sgt_iter sgt_iter;
struct page *page;
int i;
if (obj->bit_17 == NULL)
return;
i = 0;
for_each_sgt_page(page, sgt_iter, obj->pages) {
char new_bit_17 = page_to_phys(page) >> 17;
if ((new_bit_17 & 0x1) !=
(test_bit(i, obj->bit_17) != 0)) {
i915_gem_swizzle_page(page);
set_page_dirty(page);
}
i++;
}
}
/**
* i915_gem_object_save_bit_17_swizzle - save bit 17 swizzling
* @obj: i915 GEM buffer object
*
* This function saves the bit 17 of each page frame number so that swizzling
* can be fixed up later on with i915_gem_object_do_bit_17_swizzle(). This must
* be called before the backing storage can be unpinned.
*/
void
i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj)
{
struct sgt_iter sgt_iter;
struct page *page;
int page_count = obj->base.size >> PAGE_SHIFT;
int i;
if (obj->bit_17 == NULL) {
obj->bit_17 = kcalloc(BITS_TO_LONGS(page_count),
sizeof(long), GFP_KERNEL);
if (obj->bit_17 == NULL) {
DRM_ERROR("Failed to allocate memory for bit 17 "
"record\n");
return;
}
}
i = 0;
for_each_sgt_page(page, sgt_iter, obj->pages) {
if (page_to_phys(page) & (1 << 17))
__set_bit(i, obj->bit_17);
else
__clear_bit(i, obj->bit_17);
i++;
}
}
