--- /dev/null
+/*
+ * 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)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ 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)) {
+ uint32_t ddc2 = I915_READ(DCC2);
+
+ if (!(ddc2 & DCC2_MODIFIED_ENHANCED_DISABLE))
+ dev_priv->quirks |= QUIRK_PIN_SWIZZLED_PAGES;
+ }
+
+ 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 (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_gtt_size(obj->base.dev, 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;
+}
+
+/**
+ * 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;
+ struct drm_i915_private *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;
+ }
+
+ mutex_lock(&dev->struct_mutex);
+ if (i915_gem_obj_is_pinned(obj) || 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 != 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.
+ */
+ if (obj->map_and_fenceable &&
+ !i915_gem_object_fence_ok(obj, args->tiling_mode))
+ ret = i915_gem_object_ggtt_unbind(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 (obj->tiling_mode == I915_TILING_NONE)
+ i915_gem_object_pin_pages(obj);
+ }
+
+ obj->fence_dirty =
+ obj->last_fenced_req ||
+ 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 = kcalloc(BITS_TO_LONGS(obj->base.size >> PAGE_SHIFT),
+ sizeof(long), GFP_KERNEL);
+ }
+ } else {
+ kfree(obj->bit_17);
+ obj->bit_17 = NULL;
+ }
+
+err:
+ 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;
+ struct drm_i915_private *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 */
+ 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;
+
+ 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 = 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_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++;
+ }
+}
Code Review / kvmfornfv.git / blobdiff