2 * SPDX-License-Identifier: MIT
4 * Copyright © 2008 Intel Corporation
7 #include <linux/string.h>
8 #include <linux/bitops.h>
12 #include "i915_gem_ioctls.h"
13 #include "i915_gem_mman.h"
14 #include "i915_gem_object.h"
17 * DOC: buffer object tiling
19 * i915_gem_set_tiling_ioctl() and i915_gem_get_tiling_ioctl() is the userspace
20 * interface to declare fence register requirements.
22 * In principle GEM doesn't care at all about the internal data layout of an
23 * object, and hence it also doesn't care about tiling or swizzling. There's two
26 * - For X and Y tiling the hardware provides detilers for CPU access, so called
27 * fences. Since there's only a limited amount of them the kernel must manage
28 * these, and therefore userspace must tell the kernel the object tiling if it
29 * wants to use fences for detiling.
30 * - On gen3 and gen4 platforms have a swizzling pattern for tiled objects which
31 * depends upon the physical page frame number. When swapping such objects the
32 * page frame number might change and the kernel must be able to fix this up
33 * and hence now the tiling. Note that on a subset of platforms with
34 * asymmetric memory channel population the swizzling pattern changes in an
35 * unknown way, and for those the kernel simply forbids swapping completely.
37 * Since neither of this applies for new tiling layouts on modern platforms like
38 * W, Ys and Yf tiling GEM only allows object tiling to be set to X or Y tiled.
39 * Anything else can be handled in userspace entirely without the kernel's
44 * i915_gem_fence_size - required global GTT size for a fence
47 * @tiling: tiling mode
48 * @stride: tiling stride
50 * Return the required global GTT size for a fence (view of a tiled object),
51 * taking into account potential fence register mapping.
53 u32 i915_gem_fence_size(struct drm_i915_private *i915,
54 u32 size, unsigned int tiling, unsigned int stride)
60 if (tiling == I915_TILING_NONE)
65 if (INTEL_GEN(i915) >= 4) {
66 stride *= i915_gem_tile_height(tiling);
67 GEM_BUG_ON(!IS_ALIGNED(stride, I965_FENCE_PAGE));
68 return roundup(size, stride);
71 /* Previous chips need a power-of-two fence region when tiling */
73 ggtt_size = 1024*1024;
77 while (ggtt_size < size)
84 * i915_gem_fence_alignment - required global GTT alignment for a fence
87 * @tiling: tiling mode
88 * @stride: tiling stride
90 * Return the required global GTT alignment for a fence (a view of a tiled
91 * object), taking into account potential fence register mapping.
93 u32 i915_gem_fence_alignment(struct drm_i915_private *i915, u32 size,
94 unsigned int tiling, unsigned int stride)
99 * Minimum alignment is 4k (GTT page size), but might be greater
100 * if a fence register is needed for the object.
102 if (tiling == I915_TILING_NONE)
103 return I915_GTT_MIN_ALIGNMENT;
105 if (INTEL_GEN(i915) >= 4)
106 return I965_FENCE_PAGE;
109 * Previous chips need to be aligned to the size of the smallest
110 * fence register that can contain the object.
112 return i915_gem_fence_size(i915, size, tiling, stride);
115 /* Check pitch constriants for all chips & tiling formats */
117 i915_tiling_ok(struct drm_i915_gem_object *obj,
118 unsigned int tiling, unsigned int stride)
120 struct drm_i915_private *i915 = to_i915(obj->base.dev);
121 unsigned int tile_width;
123 /* Linear is always fine */
124 if (tiling == I915_TILING_NONE)
127 if (tiling > I915_TILING_LAST)
130 /* check maximum stride & object size */
131 /* i965+ stores the end address of the gtt mapping in the fence
132 * reg, so dont bother to check the size */
133 if (INTEL_GEN(i915) >= 7) {
134 if (stride / 128 > GEN7_FENCE_MAX_PITCH_VAL)
136 } else if (INTEL_GEN(i915) >= 4) {
137 if (stride / 128 > I965_FENCE_MAX_PITCH_VAL)
143 if (!is_power_of_2(stride))
147 if (IS_GEN(i915, 2) ||
148 (tiling == I915_TILING_Y && HAS_128_BYTE_Y_TILING(i915)))
153 if (!stride || !IS_ALIGNED(stride, tile_width))
159 static bool i915_vma_fence_prepare(struct i915_vma *vma,
160 int tiling_mode, unsigned int stride)
162 struct drm_i915_private *i915 = vma->vm->i915;
165 if (!i915_vma_is_map_and_fenceable(vma))
168 size = i915_gem_fence_size(i915, vma->size, tiling_mode, stride);
169 if (vma->node.size < size)
172 alignment = i915_gem_fence_alignment(i915, vma->size, tiling_mode, stride);
173 if (!IS_ALIGNED(vma->node.start, alignment))
179 /* Make the current GTT allocation valid for the change in tiling. */
181 i915_gem_object_fence_prepare(struct drm_i915_gem_object *obj,
182 int tiling_mode, unsigned int stride)
184 struct i915_ggtt *ggtt = &to_i915(obj->base.dev)->ggtt;
185 struct i915_vma *vma;
188 if (tiling_mode == I915_TILING_NONE)
191 mutex_lock(&ggtt->vm.mutex);
192 for_each_ggtt_vma(vma, obj) {
193 if (i915_vma_fence_prepare(vma, tiling_mode, stride))
196 ret = __i915_vma_unbind(vma);
200 mutex_unlock(&ggtt->vm.mutex);
206 i915_gem_object_set_tiling(struct drm_i915_gem_object *obj,
207 unsigned int tiling, unsigned int stride)
209 struct drm_i915_private *i915 = to_i915(obj->base.dev);
210 struct i915_vma *vma;
213 /* Make sure we don't cross-contaminate obj->tiling_and_stride */
214 BUILD_BUG_ON(I915_TILING_LAST & STRIDE_MASK);
216 GEM_BUG_ON(!i915_tiling_ok(obj, tiling, stride));
217 GEM_BUG_ON(!stride ^ (tiling == I915_TILING_NONE));
219 if ((tiling | stride) == obj->tiling_and_stride)
222 if (i915_gem_object_is_framebuffer(obj))
225 /* We need to rebind the object if its current allocation
226 * no longer meets the alignment restrictions for its new
227 * tiling mode. Otherwise we can just leave it alone, but
228 * need to ensure that any fence register is updated before
229 * the next fenced (either through the GTT or by the BLT unit
230 * on older GPUs) access.
232 * After updating the tiling parameters, we then flag whether
233 * we need to update an associated fence register. Note this
234 * has to also include the unfenced register the GPU uses
235 * whilst executing a fenced command for an untiled object.
238 i915_gem_object_lock(obj);
239 if (i915_gem_object_is_framebuffer(obj)) {
240 i915_gem_object_unlock(obj);
244 err = i915_gem_object_fence_prepare(obj, tiling, stride);
246 i915_gem_object_unlock(obj);
250 /* If the memory has unknown (i.e. varying) swizzling, we pin the
251 * pages to prevent them being swapped out and causing corruption
252 * due to the change in swizzling.
254 mutex_lock(&obj->mm.lock);
255 if (i915_gem_object_has_pages(obj) &&
256 obj->mm.madv == I915_MADV_WILLNEED &&
257 i915->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
258 if (tiling == I915_TILING_NONE) {
259 GEM_BUG_ON(!obj->mm.quirked);
260 __i915_gem_object_unpin_pages(obj);
261 obj->mm.quirked = false;
263 if (!i915_gem_object_is_tiled(obj)) {
264 GEM_BUG_ON(obj->mm.quirked);
265 __i915_gem_object_pin_pages(obj);
266 obj->mm.quirked = true;
269 mutex_unlock(&obj->mm.lock);
271 for_each_ggtt_vma(vma, obj) {
273 i915_gem_fence_size(i915, vma->size, tiling, stride);
274 vma->fence_alignment =
275 i915_gem_fence_alignment(i915,
276 vma->size, tiling, stride);
279 vma->fence->dirty = true;
282 obj->tiling_and_stride = tiling | stride;
283 i915_gem_object_unlock(obj);
285 /* Force the fence to be reacquired for GTT access */
286 i915_gem_object_release_mmap(obj);
288 /* Try to preallocate memory required to save swizzling on put-pages */
289 if (i915_gem_object_needs_bit17_swizzle(obj)) {
291 obj->bit_17 = bitmap_zalloc(obj->base.size >> PAGE_SHIFT,
295 bitmap_free(obj->bit_17);
303 * i915_gem_set_tiling_ioctl - IOCTL handler to set tiling mode
305 * @data: data pointer for the ioctl
306 * @file: DRM file for the ioctl call
308 * Sets the tiling mode of an object, returning the required swizzling of
309 * bit 6 of addresses in the object.
311 * Called by the user via ioctl.
314 * Zero on success, negative errno on failure.
317 i915_gem_set_tiling_ioctl(struct drm_device *dev, void *data,
318 struct drm_file *file)
320 struct drm_i915_private *dev_priv = to_i915(dev);
321 struct drm_i915_gem_set_tiling *args = data;
322 struct drm_i915_gem_object *obj;
325 if (!dev_priv->ggtt.num_fences)
328 obj = i915_gem_object_lookup(file, args->handle);
333 * The tiling mode of proxy objects is handled by its generator, and
334 * not allowed to be changed by userspace.
336 if (i915_gem_object_is_proxy(obj)) {
341 if (!i915_tiling_ok(obj, args->tiling_mode, args->stride)) {
346 if (args->tiling_mode == I915_TILING_NONE) {
347 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
350 if (args->tiling_mode == I915_TILING_X)
351 args->swizzle_mode = to_i915(dev)->ggtt.bit_6_swizzle_x;
353 args->swizzle_mode = to_i915(dev)->ggtt.bit_6_swizzle_y;
355 /* Hide bit 17 swizzling from the user. This prevents old Mesa
356 * from aborting the application on sw fallbacks to bit 17,
357 * and we use the pread/pwrite bit17 paths to swizzle for it.
358 * If there was a user that was relying on the swizzle
359 * information for drm_intel_bo_map()ed reads/writes this would
360 * break it, but we don't have any of those.
362 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
363 args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
364 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
365 args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;
367 /* If we can't handle the swizzling, make it untiled. */
368 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_UNKNOWN) {
369 args->tiling_mode = I915_TILING_NONE;
370 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
375 err = i915_gem_object_set_tiling(obj, args->tiling_mode, args->stride);
377 /* We have to maintain this existing ABI... */
378 args->stride = i915_gem_object_get_stride(obj);
379 args->tiling_mode = i915_gem_object_get_tiling(obj);
382 i915_gem_object_put(obj);
387 * i915_gem_get_tiling_ioctl - IOCTL handler to get tiling mode
389 * @data: data pointer for the ioctl
390 * @file: DRM file for the ioctl call
392 * Returns the current tiling mode and required bit 6 swizzling for the object.
394 * Called by the user via ioctl.
397 * Zero on success, negative errno on failure.
400 i915_gem_get_tiling_ioctl(struct drm_device *dev, void *data,
401 struct drm_file *file)
403 struct drm_i915_gem_get_tiling *args = data;
404 struct drm_i915_private *dev_priv = to_i915(dev);
405 struct drm_i915_gem_object *obj;
408 if (!dev_priv->ggtt.num_fences)
412 obj = i915_gem_object_lookup_rcu(file, args->handle);
415 READ_ONCE(obj->tiling_and_stride) & TILING_MASK;
422 switch (args->tiling_mode) {
424 args->swizzle_mode = dev_priv->ggtt.bit_6_swizzle_x;
427 args->swizzle_mode = dev_priv->ggtt.bit_6_swizzle_y;
430 case I915_TILING_NONE:
431 args->swizzle_mode = I915_BIT_6_SWIZZLE_NONE;
435 /* Hide bit 17 from the user -- see comment in i915_gem_set_tiling */
436 if (dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES)
437 args->phys_swizzle_mode = I915_BIT_6_SWIZZLE_UNKNOWN;
439 args->phys_swizzle_mode = args->swizzle_mode;
440 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_17)
441 args->swizzle_mode = I915_BIT_6_SWIZZLE_9;
442 if (args->swizzle_mode == I915_BIT_6_SWIZZLE_9_10_17)
443 args->swizzle_mode = I915_BIT_6_SWIZZLE_9_10;