2 * Copyright © 2008 Intel Corporation
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
24 * Eric Anholt <eric@anholt.net>
28 #include <linux/acpi.h>
29 #include <linux/pnp.h>
30 #include "linux/string.h"
31 #include "linux/bitops.h"
37 /** @file i915_gem_tiling.c
39 * Support for managing tiling state of buffer objects.
41 * The idea behind tiling is to increase cache hit rates by rearranging
42 * pixel data so that a group of pixel accesses are in the same cacheline.
43 * Performance improvement from doing this on the back/depth buffer are on
46 * Intel architectures make this somewhat more complicated, though, by
47 * adjustments made to addressing of data when the memory is in interleaved
48 * mode (matched pairs of DIMMS) to improve memory bandwidth.
49 * For interleaved memory, the CPU sends every sequential 64 bytes
50 * to an alternate memory channel so it can get the bandwidth from both.
52 * The GPU also rearranges its accesses for increased bandwidth to interleaved
53 * memory, and it matches what the CPU does for non-tiled. However, when tiled
54 * it does it a little differently, since one walks addresses not just in the
55 * X direction but also Y. So, along with alternating channels when bit
56 * 6 of the address flips, it also alternates when other bits flip -- Bits 9
57 * (every 512 bytes, an X tile scanline) and 10 (every two X tile scanlines)
58 * are common to both the 915 and 965-class hardware.
60 * The CPU also sometimes XORs in higher bits as well, to improve
61 * bandwidth doing strided access like we do so frequently in graphics. This
62 * is called "Channel XOR Randomization" in the MCH documentation. The result
63 * is that the CPU is XORing in either bit 11 or bit 17 to bit 6 of its address
66 * All of this bit 6 XORing has an effect on our memory management,
67 * as we need to make sure that the 3d driver can correctly address object
70 * If we don't have interleaved memory, all tiling is safe and no swizzling is
73 * When bit 17 is XORed in, we simply refuse to tile at all. Bit
74 * 17 is not just a page offset, so as we page an objet out and back in,
75 * individual pages in it will have different bit 17 addresses, resulting in
76 * each 64 bytes being swapped with its neighbor!
78 * Otherwise, if interleaved, we have to tell the 3d driver what the address
79 * swizzling it needs to do is, since it's writing with the CPU to the pages
80 * (bit 6 and potentially bit 11 XORed in), and the GPU is reading from the
81 * pages (bit 6, 9, and 10 XORed in), resulting in a cumulative bit swizzling
82 * required by the CPU of XORing in bit 6, 9, 10, and potentially 11, in order
83 * to match what the GPU expects.
86 #define MCHBAR_I915 0x44
87 #define MCHBAR_I965 0x48
88 #define MCHBAR_SIZE (4*4096)
90 #define DEVEN_REG 0x54
91 #define DEVEN_MCHBAR_EN (1 << 28)
93 /* Allocate space for the MCH regs if needed, return nonzero on error */
95 intel_alloc_mchbar_resource(struct drm_device *dev)
97 struct pci_dev *bridge_dev;
98 drm_i915_private_t *dev_priv = dev->dev_private;
99 int reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
100 u32 temp_lo, temp_hi = 0;
104 bridge_dev = pci_get_bus_and_slot(0, PCI_DEVFN(0,0));
106 DRM_DEBUG("no bridge dev?!\n");
112 pci_read_config_dword(bridge_dev, reg + 4, &temp_hi);
113 pci_read_config_dword(bridge_dev, reg, &temp_lo);
114 mchbar_addr = ((u64)temp_hi << 32) | temp_lo;
116 /* If ACPI doesn't have it, assume we need to allocate it ourselves */
119 pnp_range_reserved(mchbar_addr, mchbar_addr + MCHBAR_SIZE)) {
125 /* Get some space for it */
126 ret = pci_bus_alloc_resource(bridge_dev->bus, &dev_priv->mch_res,
127 MCHBAR_SIZE, MCHBAR_SIZE,
129 0, pcibios_align_resource,
132 DRM_DEBUG("failed bus alloc: %d\n", ret);
133 dev_priv->mch_res.start = 0;
138 pci_write_config_dword(bridge_dev, reg + 4,
139 upper_32_bits(dev_priv->mch_res.start));
141 pci_write_config_dword(bridge_dev, reg,
142 lower_32_bits(dev_priv->mch_res.start));
144 pci_dev_put(bridge_dev);
149 /* Setup MCHBAR if possible, return true if we should disable it again */
151 intel_setup_mchbar(struct drm_device *dev)
153 struct pci_dev *bridge_dev;
154 int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
156 bool need_disable = false, enabled;
158 bridge_dev = pci_get_bus_and_slot(0, PCI_DEVFN(0,0));
160 DRM_DEBUG("no bridge dev?!\n");
164 if (IS_I915G(dev) || IS_I915GM(dev)) {
165 pci_read_config_dword(bridge_dev, DEVEN_REG, &temp);
166 enabled = !!(temp & DEVEN_MCHBAR_EN);
168 pci_read_config_dword(bridge_dev, mchbar_reg, &temp);
172 /* If it's already enabled, don't have to do anything */
176 if (intel_alloc_mchbar_resource(dev))
181 /* Space is allocated or reserved, so enable it. */
182 if (IS_I915G(dev) || IS_I915GM(dev)) {
183 pci_write_config_dword(bridge_dev, DEVEN_REG,
184 temp | DEVEN_MCHBAR_EN);
186 pci_read_config_dword(bridge_dev, mchbar_reg, &temp);
187 pci_write_config_dword(bridge_dev, mchbar_reg, temp | 1);
190 pci_dev_put(bridge_dev);
196 intel_teardown_mchbar(struct drm_device *dev, bool disable)
198 drm_i915_private_t *dev_priv = dev->dev_private;
199 struct pci_dev *bridge_dev;
200 int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
203 bridge_dev = pci_get_bus_and_slot(0, PCI_DEVFN(0,0));
205 DRM_DEBUG("no bridge dev?!\n");
210 if (IS_I915G(dev) || IS_I915GM(dev)) {
211 pci_read_config_dword(bridge_dev, DEVEN_REG, &temp);
212 temp &= ~DEVEN_MCHBAR_EN;
213 pci_write_config_dword(bridge_dev, DEVEN_REG, temp);
215 pci_read_config_dword(bridge_dev, mchbar_reg, &temp);
217 pci_write_config_dword(bridge_dev, mchbar_reg, temp);
221 if (dev_priv->mch_res.start)
222 release_resource(&dev_priv->mch_res);
226 * Detects bit 6 swizzling of address lookup between IGD access and CPU
227 * access through main memory.
230 i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
232 drm_i915_private_t *dev_priv = dev->dev_private;
233 uint32_t swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
234 uint32_t swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
238 /* On IGDNG whatever DRAM config, GPU always do
239 * same swizzling setup.
241 swizzle_x = I915_BIT_6_SWIZZLE_9_10;
242 swizzle_y = I915_BIT_6_SWIZZLE_9;
243 } else if (!IS_I9XX(dev)) {
244 /* As far as we know, the 865 doesn't have these bit 6
247 swizzle_x = I915_BIT_6_SWIZZLE_NONE;
248 swizzle_y = I915_BIT_6_SWIZZLE_NONE;
249 } else if (IS_MOBILE(dev)) {
252 /* Try to make sure MCHBAR is enabled before poking at it */
253 need_disable = intel_setup_mchbar(dev);
255 /* On mobile 9xx chipsets, channel interleave by the CPU is
256 * determined by DCC. For single-channel, neither the CPU
257 * nor the GPU do swizzling. For dual channel interleaved,
258 * the GPU's interleave is bit 9 and 10 for X tiled, and bit
259 * 9 for Y tiled. The CPU's interleave is independent, and
260 * can be based on either bit 11 (haven't seen this yet) or
263 dcc = I915_READ(DCC);
264 switch (dcc & DCC_ADDRESSING_MODE_MASK) {
265 case DCC_ADDRESSING_MODE_SINGLE_CHANNEL:
266 case DCC_ADDRESSING_MODE_DUAL_CHANNEL_ASYMMETRIC:
267 swizzle_x = I915_BIT_6_SWIZZLE_NONE;
268 swizzle_y = I915_BIT_6_SWIZZLE_NONE;
270 case DCC_ADDRESSING_MODE_DUAL_CHANNEL_INTERLEAVED:
271 if (dcc & DCC_CHANNEL_XOR_DISABLE) {
272 /* This is the base swizzling by the GPU for
275 swizzle_x = I915_BIT_6_SWIZZLE_9_10;
276 swizzle_y = I915_BIT_6_SWIZZLE_9;
277 } else if ((dcc & DCC_CHANNEL_XOR_BIT_17) == 0) {
278 /* Bit 11 swizzling by the CPU in addition. */
279 swizzle_x = I915_BIT_6_SWIZZLE_9_10_11;
280 swizzle_y = I915_BIT_6_SWIZZLE_9_11;
282 /* Bit 17 swizzling by the CPU in addition. */
283 swizzle_x = I915_BIT_6_SWIZZLE_9_10_17;
284 swizzle_y = I915_BIT_6_SWIZZLE_9_17;
288 if (dcc == 0xffffffff) {
289 DRM_ERROR("Couldn't read from MCHBAR. "
290 "Disabling tiling.\n");
291 swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
292 swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
295 intel_teardown_mchbar(dev, need_disable);
297 /* The 965, G33, and newer, have a very flexible memory
298 * configuration. It will enable dual-channel mode
299 * (interleaving) on as much memory as it can, and the GPU
300 * will additionally sometimes enable different bit 6
301 * swizzling for tiled objects from the CPU.
303 * Here's what I found on the G965:
304 * slot fill memory size swizzling
305 * 0A 0B 1A 1B 1-ch 2-ch
307 * 512 0 512 0 16 1008 X
308 * 512 0 0 512 16 1008 X
309 * 0 512 0 512 16 1008 X
310 * 1024 1024 1024 0 2048 1024 O
312 * We could probably detect this based on either the DRB
313 * matching, which was the case for the swizzling required in
314 * the table above, or from the 1-ch value being less than
315 * the minimum size of a rank.
317 if (I915_READ16(C0DRB3) != I915_READ16(C1DRB3)) {
318 swizzle_x = I915_BIT_6_SWIZZLE_NONE;
319 swizzle_y = I915_BIT_6_SWIZZLE_NONE;
321 swizzle_x = I915_BIT_6_SWIZZLE_9_10;
322 swizzle_y = I915_BIT_6_SWIZZLE_9;
326 dev_priv->mm.bit_6_swizzle_x = swizzle_x;
327 dev_priv->mm.bit_6_swizzle_y = swizzle_y;
332 * Returns the size of the fence for a tiled object of the given size.
335 i915_get_fence_size(struct drm_device *dev, int size)
341 /* The 965 can have fences at any page boundary. */
342 return ALIGN(size, 4096);
344 /* Align the size to a power of two greater than the smallest
352 for (i = start; i < size; i <<= 1)
359 /* Check pitch constriants for all chips & tiling formats */
361 i915_tiling_ok(struct drm_device *dev, int stride, int size, int tiling_mode)
365 /* Linear is always fine */
366 if (tiling_mode == I915_TILING_NONE)
370 (tiling_mode == I915_TILING_Y && HAS_128_BYTE_Y_TILING(dev)))
375 /* check maximum stride & object size */
377 /* i965 stores the end address of the gtt mapping in the fence
378 * reg, so dont bother to check the size */
379 if (stride / 128 > I965_FENCE_MAX_PITCH_VAL)
381 } else if (IS_I9XX(dev)) {
382 uint32_t pitch_val = ffs(stride / tile_width) - 1;
384 /* XXX: For Y tiling, FENCE_MAX_PITCH_VAL is actually 6 (8KB)
385 * instead of 4 (2KB) on 945s.
387 if (pitch_val > I915_FENCE_MAX_PITCH_VAL ||
388 size > (I830_FENCE_MAX_SIZE_VAL << 20))
391 uint32_t pitch_val = ffs(stride / tile_width) - 1;
393 if (pitch_val > I830_FENCE_MAX_PITCH_VAL ||
394 size > (I830_FENCE_MAX_SIZE_VAL << 19))
398 /* 965+ just needs multiples of tile width */
400 if (stride & (tile_width - 1))
405 /* Pre-965 needs power of two tile widths */
406 if (stride < tile_width)
409 if (stride & (stride - 1))
412 /* We don't 0handle the aperture area covered by the fence being bigger
413 * than the object size.
415 if (i915_get_fence_size(dev, size) != size)
422 i915_gem_object_fence_offset_ok(struct drm_gem_object *obj, int tiling_mode)
424 struct drm_device *dev = obj->dev;
425 struct drm_i915_gem_object *obj_priv = obj->driver_private;
427 if (obj_priv->gtt_space == NULL)
430 if (tiling_mode == I915_TILING_NONE)
433 if (!IS_I965G(dev)) {
434 if (obj_priv->gtt_offset & (obj->size - 1))
437 if (obj_priv->gtt_offset & ~I915_FENCE_START_MASK)
440 if (obj_priv->gtt_offset & ~I830_FENCE_START_MASK)
449 * Sets the tiling mode of an object, returning the required swizzling of
450 * bit 6 of addresses in the object.
453 i915_gem_set_tiling(struct drm_device *dev, void *data,
454 struct drm_file *file_priv)
456 struct drm_i915_gem_set_tiling *args = data;
457 drm_i915_private_t *dev_priv = dev->dev_private;
458 struct drm_gem_object *obj;
459 struct drm_i915_gem_object *obj_priv;
462 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
465 obj_priv = obj->driver_private;
467 if (!i915_tiling_ok(dev, args->stride, obj->size, args->tiling_mode)) {
468 mutex_lock(&dev->struct_mutex);
469 drm_gem_object_unreference(obj);
470 mutex_unlock(&dev->struct_mutex);
474 if (args->tiling_mode == I915_TILING_NONE) {
475 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
478 if (args->tiling_mode == I915_TILING_X)
479 args->swizzle_mode = dev_priv->mm.bit_6_swizzle_x;
481 args->swizzle_mode = dev_priv->mm.bit_6_swizzle_y;
483 /* Hide bit 17 swizzling from the user. This prevents old Mesa
484 * from aborting the application on sw fallbacks to bit 17,
485 * and we use the pread/pwrite bit17 paths to swizzle for it.
486 * If there was a user that was relying on the swizzle
487 * information for drm_intel_bo_map()ed reads/writes this would
488 * break it, but we don't have any of those.
490 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
491 args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
492 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
493 args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
495 /* If we can't handle the swizzling, make it untiled. */
496 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_UNKNOWN) {
497 args->tiling_mode = I915_TILING_NONE;
498 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
503 mutex_lock(&dev->struct_mutex);
504 if (args->tiling_mode != obj_priv->tiling_mode ||
505 args->stride != obj_priv->stride) {
506 /* We need to rebind the object if its current allocation
507 * no longer meets the alignment restrictions for its new
508 * tiling mode. Otherwise we can just leave it alone, but
509 * need to ensure that any fence register is cleared.
511 if (!i915_gem_object_fence_offset_ok(obj, args->tiling_mode))
512 ret = i915_gem_object_unbind(obj);
514 ret = i915_gem_object_put_fence_reg(obj);
516 WARN(ret != -ERESTARTSYS,
517 "failed to reset object for tiling switch");
518 args->tiling_mode = obj_priv->tiling_mode;
519 args->stride = obj_priv->stride;
523 /* If we've changed tiling, GTT-mappings of the object
524 * need to re-fault to ensure that the correct fence register
527 i915_gem_release_mmap(obj);
529 obj_priv->tiling_mode = args->tiling_mode;
530 obj_priv->stride = args->stride;
533 drm_gem_object_unreference(obj);
534 mutex_unlock(&dev->struct_mutex);
540 * Returns the current tiling mode and required bit 6 swizzling for the object.
543 i915_gem_get_tiling(struct drm_device *dev, void *data,
544 struct drm_file *file_priv)
546 struct drm_i915_gem_get_tiling *args = data;
547 drm_i915_private_t *dev_priv = dev->dev_private;
548 struct drm_gem_object *obj;
549 struct drm_i915_gem_object *obj_priv;
551 obj = drm_gem_object_lookup(dev, file_priv, args->handle);
554 obj_priv = obj->driver_private;
556 mutex_lock(&dev->struct_mutex);
558 args->tiling_mode = obj_priv->tiling_mode;
559 switch (obj_priv->tiling_mode) {
561 args->swizzle_mode = dev_priv->mm.bit_6_swizzle_x;
564 args->swizzle_mode = dev_priv->mm.bit_6_swizzle_y;
566 case I915_TILING_NONE:
567 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
570 DRM_ERROR("unknown tiling mode\n");
573 /* Hide bit 17 from the user -- see comment in i915_gem_set_tiling */
574 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
575 args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
576 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
577 args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
579 drm_gem_object_unreference(obj);
580 mutex_unlock(&dev->struct_mutex);
586 * Swap every 64 bytes of this page around, to account for it having a new
587 * bit 17 of its physical address and therefore being interpreted differently
591 i915_gem_swizzle_page(struct page *page)
601 for (i = 0; i < PAGE_SIZE; i += 128) {
602 memcpy(temp, &vaddr[i], 64);
603 memcpy(&vaddr[i], &vaddr[i + 64], 64);
604 memcpy(&vaddr[i + 64], temp, 64);
613 i915_gem_object_do_bit_17_swizzle(struct drm_gem_object *obj)
615 struct drm_device *dev = obj->dev;
616 drm_i915_private_t *dev_priv = dev->dev_private;
617 struct drm_i915_gem_object *obj_priv = obj->driver_private;
618 int page_count = obj->size >> PAGE_SHIFT;
621 if (dev_priv->mm.bit_6_swizzle_x != I915_BIT_6_SWIZZLE_9_10_17)
624 if (obj_priv->bit_17 == NULL)
627 for (i = 0; i < page_count; i++) {
628 char new_bit_17 = page_to_phys(obj_priv->pages[i]) >> 17;
629 if ((new_bit_17 & 0x1) !=
630 (test_bit(i, obj_priv->bit_17) != 0)) {
631 int ret = i915_gem_swizzle_page(obj_priv->pages[i]);
633 DRM_ERROR("Failed to swizzle page\n");
636 set_page_dirty(obj_priv->pages[i]);
642 i915_gem_object_save_bit_17_swizzle(struct drm_gem_object *obj)
644 struct drm_device *dev = obj->dev;
645 drm_i915_private_t *dev_priv = dev->dev_private;
646 struct drm_i915_gem_object *obj_priv = obj->driver_private;
647 int page_count = obj->size >> PAGE_SHIFT;
650 if (dev_priv->mm.bit_6_swizzle_x != I915_BIT_6_SWIZZLE_9_10_17)
653 if (obj_priv->bit_17 == NULL) {
654 obj_priv->bit_17 = kmalloc(BITS_TO_LONGS(page_count) *
655 sizeof(long), GFP_KERNEL);
656 if (obj_priv->bit_17 == NULL) {
657 DRM_ERROR("Failed to allocate memory for bit 17 "
663 for (i = 0; i < page_count; i++) {
664 if (page_to_phys(obj_priv->pages[i]) & (1 << 17))
665 __set_bit(i, obj_priv->bit_17);
667 __clear_bit(i, obj_priv->bit_17);