X-Git-Url: https://gerrit.opnfv.org/gerrit/gitweb?a=blobdiff_plain;ds=sidebyside;f=kernel%2Fdrivers%2Fgpu%2Fdrm%2Fi915%2Fi915_gem_tiling.c;h=8a6717cc265c6c0a062d8cae9d4dc966356fa028;hb=e09b41010ba33a20a87472ee821fa407a5b8da36;hp=7ee23d1d1e744414c6591fe4114258026b441a36;hpb=f93b97fd65072de626c074dbe099a1fff05ce060;p=kvmfornfv.git diff --git a/kernel/drivers/gpu/drm/i915/i915_gem_tiling.c b/kernel/drivers/gpu/drm/i915/i915_gem_tiling.c index 7ee23d1d1..8a6717cc2 100644 --- a/kernel/drivers/gpu/drm/i915/i915_gem_tiling.c +++ b/kernel/drivers/gpu/drm/i915/i915_gem_tiling.c @@ -31,201 +31,32 @@ #include #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. +/** + * DOC: buffer object tiling * - * 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. + * i915_gem_set_tiling() and i915_gem_get_tiling() is the userspace interface to + * declare fence register requirements. * - * If we don't have interleaved memory, all tiling is safe and no swizzling is - * required. + * In principle GEM doesn't care at all about the internal data layout of an + * object, and hence it also doesn't care about tiling or swizzling. There's two + * exceptions: * - * 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! + * - For X and Y tiling the hardware provides detilers for CPU access, so called + * fences. Since there's only a limited amount of them the kernel must manage + * these, and therefore userspace must tell the kernel the object tiling if it + * wants to use fences for detiling. + * - On gen3 and gen4 platforms have a swizzling pattern for tiled objects which + * depends upon the physical page frame number. When swapping such objects the + * page frame number might change and the kernel must be able to fix this up + * and hence now the tiling. Note that on a subset of platforms with + * asymmetric memory channel population the swizzling pattern changes in an + * unknown way, and for those the kernel simply forbids swapping completely. * - * 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. + * Since neither of this applies for new tiling layouts on modern platforms like + * W, Ys and Yf tiling GEM only allows object tiling to be set to X or Y tiled. + * Anything else can be handled in userspace entirely without the kernel's + * invovlement. */ -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 @@ -313,8 +144,18 @@ i915_gem_object_fence_ok(struct drm_i915_gem_object *obj, int tiling_mode) } /** + * i915_gem_set_tiling - IOCTL handler to set tiling mode + * @dev: DRM device + * @data: data pointer for the ioctl + * @file: DRM file for the ioctl call + * * Sets the tiling mode of an object, returning the required swizzling of * bit 6 of addresses in the object. + * + * Called by the user via ioctl. + * + * Returns: + * Zero on success, negative errno on failure. */ int i915_gem_set_tiling(struct drm_device *dev, void *data, @@ -336,7 +177,7 @@ i915_gem_set_tiling(struct drm_device *dev, void *data, } mutex_lock(&dev->struct_mutex); - if (i915_gem_obj_is_pinned(obj) || obj->framebuffer_references) { + if (obj->pin_display || obj->framebuffer_references) { ret = -EBUSY; goto err; } @@ -432,7 +273,17 @@ err: } /** + * i915_gem_get_tiling - IOCTL handler to get tiling mode + * @dev: DRM device + * @data: data pointer for the ioctl + * @file: DRM file for the ioctl call + * * Returns the current tiling mode and required bit 6 swizzling for the object. + * + * Called by the user via ioctl. + * + * Returns: + * Zero on success, negative errno on failure. */ int i915_gem_get_tiling(struct drm_device *dev, void *data, @@ -478,75 +329,3 @@ i915_gem_get_tiling(struct drm_device *dev, void *data, 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++; - } -}