| /* |
| * 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 "drmP.h" |
| #include "drm.h" |
| #include "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_I9XX(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)) { |
| uint32_t dcc; |
| |
| /* On mobile 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_UNKNOWN; |
| swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN; |
| } |
| 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; |
| } |
| |
| |
| /** |
| * Returns the size of the fence for a tiled object of the given size. |
| */ |
| static int |
| i915_get_fence_size(struct drm_device *dev, int size) |
| { |
| int i; |
| int start; |
| |
| if (IS_I965G(dev)) { |
| /* The 965 can have fences at any page boundary. */ |
| return ALIGN(size, 4096); |
| } else { |
| /* Align the size to a power of two greater than the smallest |
| * fence size. |
| */ |
| if (IS_I9XX(dev)) |
| start = 1024 * 1024; |
| else |
| start = 512 * 1024; |
| |
| for (i = start; i < size; i <<= 1) |
| ; |
| |
| return i; |
| } |
| } |
| |
| /* 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_Y && HAS_128_BYTE_Y_TILING(dev)) |
| tile_width = 128; |
| else |
| tile_width = 512; |
| |
| /* check maximum stride & object size */ |
| if (IS_I965G(dev)) { |
| /* i965 stores the end address of the gtt mapping in the fence |
| * reg, so dont bother to check the size */ |
| if (stride / 128 > I965_FENCE_MAX_PITCH_VAL) |
| return false; |
| } else if (IS_I9XX(dev)) { |
| if (stride / tile_width > I830_FENCE_MAX_PITCH_VAL || |
| size > (I830_FENCE_MAX_SIZE_VAL << 20)) |
| return false; |
| } else { |
| if (stride / 128 > I830_FENCE_MAX_PITCH_VAL || |
| size > (I830_FENCE_MAX_SIZE_VAL << 19)) |
| return false; |
| } |
| |
| /* 965+ just needs multiples of tile width */ |
| if (IS_I965G(dev)) { |
| if (stride & (tile_width - 1)) |
| return false; |
| return true; |
| } |
| |
| /* Pre-965 needs power of two tile widths */ |
| if (stride < tile_width) |
| return false; |
| |
| if (stride & (stride - 1)) |
| return false; |
| |
| /* We don't handle the aperture area covered by the fence being bigger |
| * than the object size. |
| */ |
| if (i915_get_fence_size(dev, size) != size) |
| 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_priv) |
| { |
| struct drm_i915_gem_set_tiling *args = data; |
| drm_i915_private_t *dev_priv = dev->dev_private; |
| struct drm_gem_object *obj; |
| struct drm_i915_gem_object *obj_priv; |
| |
| obj = drm_gem_object_lookup(dev, file_priv, args->handle); |
| if (obj == NULL) |
| return -EINVAL; |
| obj_priv = obj->driver_private; |
| |
| if (!i915_tiling_ok(dev, args->stride, obj->size, args->tiling_mode)) { |
| drm_gem_object_unreference(obj); |
| return -EINVAL; |
| } |
| |
| mutex_lock(&dev->struct_mutex); |
| |
| if (args->tiling_mode == I915_TILING_NONE) { |
| obj_priv->tiling_mode = I915_TILING_NONE; |
| args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE; |
| } 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; |
| /* 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; |
| } |
| } |
| if (args->tiling_mode != obj_priv->tiling_mode) { |
| int ret; |
| |
| /* Unbind the object, as switching tiling means we're |
| * switching the cache organization due to fencing, probably. |
| */ |
| ret = i915_gem_object_unbind(obj); |
| if (ret != 0) { |
| WARN(ret != -ERESTARTSYS, |
| "failed to unbind object for tiling switch"); |
| args->tiling_mode = obj_priv->tiling_mode; |
| mutex_unlock(&dev->struct_mutex); |
| drm_gem_object_unreference(obj); |
| |
| return ret; |
| } |
| obj_priv->tiling_mode = args->tiling_mode; |
| } |
| obj_priv->stride = args->stride; |
| |
| drm_gem_object_unreference(obj); |
| mutex_unlock(&dev->struct_mutex); |
| |
| return 0; |
| } |
| |
| /** |
| * 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_priv) |
| { |
| struct drm_i915_gem_get_tiling *args = data; |
| drm_i915_private_t *dev_priv = dev->dev_private; |
| struct drm_gem_object *obj; |
| struct drm_i915_gem_object *obj_priv; |
| |
| obj = drm_gem_object_lookup(dev, file_priv, args->handle); |
| if (obj == NULL) |
| return -EINVAL; |
| obj_priv = obj->driver_private; |
| |
| mutex_lock(&dev->struct_mutex); |
| |
| args->tiling_mode = obj_priv->tiling_mode; |
| switch (obj_priv->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"); |
| } |
| |
| drm_gem_object_unreference(obj); |
| mutex_unlock(&dev->struct_mutex); |
| |
| return 0; |
| } |