diff options
Diffstat (limited to 'drivers/gpu/drm/i915/i915_gem_tiling.c')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem_tiling.c | 523 |
1 files changed, 523 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_gem_tiling.c b/drivers/gpu/drm/i915/i915_gem_tiling.c new file mode 100644 index 0000000..537545b --- /dev/null +++ b/drivers/gpu/drm/i915/i915_gem_tiling.c @@ -0,0 +1,523 @@ +/* + * 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" + +/** @file i915_gem_tiling.c + * + * Support for managing tiling state of buffer objects. + * + * 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 objet 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. + */ + +/** + * 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) +{ + drm_i915_private_t *dev_priv = dev->dev_private; + uint32_t swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN; + uint32_t swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN; + + if (IS_VALLEYVIEW(dev)) { + swizzle_x = I915_BIT_6_SWIZZLE_NONE; + swizzle_y = I915_BIT_6_SWIZZLE_NONE; + } else if (INTEL_INFO(dev)->gen >= 6) { + 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; + } + 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. + */ + if (I915_READ16(C0DRB3) != I915_READ16(C1DRB3)) { + swizzle_x = I915_BIT_6_SWIZZLE_NONE; + swizzle_y = I915_BIT_6_SWIZZLE_NONE; + } else { + swizzle_x = I915_BIT_6_SWIZZLE_9_10; + swizzle_y = I915_BIT_6_SWIZZLE_9; + } + } + + dev_priv->mm.bit_6_swizzle_x = swizzle_x; + dev_priv->mm.bit_6_swizzle_y = swizzle_y; +} + +/* 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 (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) +{ + u32 size; + + if (tiling_mode == I915_TILING_NONE) + return true; + + if (INTEL_INFO(obj->base.dev)->gen >= 4) + return true; + + if (INTEL_INFO(obj->base.dev)->gen == 3) { + if (obj->gtt_offset & ~I915_FENCE_START_MASK) + return false; + } else { + if (obj->gtt_offset & ~I830_FENCE_START_MASK) + return false; + } + + size = i915_gem_get_gtt_size(obj->base.dev, obj->base.size, tiling_mode); + if (obj->gtt_space->size != size) + return false; + + if (obj->gtt_offset & (size - 1)) + return false; + + return true; +} + +/** + * Sets the tiling mode of an object, returning the required swizzling of + * bit 6 of addresses in the object. + */ +int +i915_gem_set_tiling(struct drm_device *dev, void *data, + struct drm_file *file) +{ + struct drm_i915_gem_set_tiling *args = data; + drm_i915_private_t *dev_priv = dev->dev_private; + struct drm_i915_gem_object *obj; + int ret = 0; + + obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle)); + if (&obj->base == NULL) + return -ENOENT; + + if (!i915_tiling_ok(dev, + args->stride, obj->base.size, args->tiling_mode)) { + drm_gem_object_unreference_unlocked(&obj->base); + return -EINVAL; + } + + if (obj->pin_count) { + drm_gem_object_unreference_unlocked(&obj->base); + return -EBUSY; + } + + 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; + } + } + + mutex_lock(&dev->struct_mutex); + if (args->tiling_mode != obj->tiling_mode || + args->stride != obj->stride) { + /* 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. + */ + + obj->map_and_fenceable = + obj->gtt_space == NULL || + (obj->gtt_offset + obj->base.size <= dev_priv->gtt.mappable_end && + i915_gem_object_fence_ok(obj, args->tiling_mode)); + + /* Rebind if we need a change of alignment */ + if (!obj->map_and_fenceable) { + u32 unfenced_alignment = + i915_gem_get_gtt_alignment(dev, obj->base.size, + args->tiling_mode, + false); + if (obj->gtt_offset & (unfenced_alignment - 1)) + ret = i915_gem_object_unbind(obj); + } + + if (ret == 0) { + obj->fence_dirty = + obj->fenced_gpu_access || + obj->fence_reg != I915_FENCE_REG_NONE; + + obj->tiling_mode = args->tiling_mode; + obj->stride = args->stride; + + /* Force the fence to be reacquired for GTT access */ + i915_gem_release_mmap(obj); + } + } + /* we have to maintain this existing ABI... */ + args->stride = obj->stride; + args->tiling_mode = obj->tiling_mode; + + /* 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 = kmalloc(BITS_TO_LONGS(obj->base.size >> PAGE_SHIFT) * + sizeof(long), GFP_KERNEL); + } + } else { + kfree(obj->bit_17); + obj->bit_17 = NULL; + } + + drm_gem_object_unreference(&obj->base); + mutex_unlock(&dev->struct_mutex); + + return ret; +} + +/** + * Returns the current tiling mode and required bit 6 swizzling for the object. + */ +int +i915_gem_get_tiling(struct drm_device *dev, void *data, + struct drm_file *file) +{ + struct drm_i915_gem_get_tiling *args = data; + drm_i915_private_t *dev_priv = dev->dev_private; + struct drm_i915_gem_object *obj; + + obj = to_intel_bo(drm_gem_object_lookup(dev, file, args->handle)); + if (&obj->base == NULL) + return -ENOENT; + + mutex_lock(&dev->struct_mutex); + + args->tiling_mode = obj->tiling_mode; + switch (obj->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 (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; + + drm_gem_object_unreference(&obj->base); + mutex_unlock(&dev->struct_mutex); + + return 0; +} + +/** + * 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); +} + +void +i915_gem_object_do_bit_17_swizzle(struct drm_i915_gem_object *obj) +{ + struct sg_page_iter sg_iter; + int i; + + if (obj->bit_17 == NULL) + return; + + i = 0; + for_each_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) { + struct page *page = sg_page_iter_page(&sg_iter); + 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++; + } +} + +void +i915_gem_object_save_bit_17_swizzle(struct drm_i915_gem_object *obj) +{ + struct sg_page_iter sg_iter; + int page_count = obj->base.size >> PAGE_SHIFT; + int i; + + if (obj->bit_17 == NULL) { + obj->bit_17 = kmalloc(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_sg_page(obj->pages->sgl, &sg_iter, obj->pages->nents, 0) { + if (page_to_phys(sg_page_iter_page(&sg_iter)) & (1 << 17)) + __set_bit(i, obj->bit_17); + else + __clear_bit(i, obj->bit_17); + i++; + } +} |