summaryrefslogtreecommitdiff
path: root/drivers/gpu/drm/i915/i915_gem_gtt.c
blob: 5101ab6869b47eef37b5be33e9b4786bc862beca (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
/*
 * Copyright © 2010 Daniel Vetter
 *
 * 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.
 *
 */

#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "i915_trace.h"
#include "intel_drv.h"

/* PPGTT stuff */
#define GEN6_GTT_ADDR_ENCODE(addr)	((addr) | (((addr) >> 28) & 0xff0))

#define GEN6_PDE_VALID			(1 << 0)
/* gen6+ has bit 11-4 for physical addr bit 39-32 */
#define GEN6_PDE_ADDR_ENCODE(addr)	GEN6_GTT_ADDR_ENCODE(addr)

#define GEN6_PTE_VALID			(1 << 0)
#define GEN6_PTE_UNCACHED		(1 << 1)
#define HSW_PTE_UNCACHED		(0)
#define GEN6_PTE_CACHE_LLC		(2 << 1)
#define GEN6_PTE_CACHE_LLC_MLC		(3 << 1)
#define GEN6_PTE_ADDR_ENCODE(addr)	GEN6_GTT_ADDR_ENCODE(addr)

static gen6_gtt_pte_t gen6_pte_encode(struct drm_device *dev,
				      dma_addr_t addr,
				      enum i915_cache_level level)
{
	gen6_gtt_pte_t pte = GEN6_PTE_VALID;
	pte |= GEN6_PTE_ADDR_ENCODE(addr);

	switch (level) {
	case I915_CACHE_LLC_MLC:
		pte |= GEN6_PTE_CACHE_LLC_MLC;
		break;
	case I915_CACHE_LLC:
		pte |= GEN6_PTE_CACHE_LLC;
		break;
	case I915_CACHE_NONE:
		pte |= GEN6_PTE_UNCACHED;
		break;
	default:
		BUG();
	}

	return pte;
}

#define BYT_PTE_WRITEABLE		(1 << 1)
#define BYT_PTE_SNOOPED_BY_CPU_CACHES	(1 << 2)

static gen6_gtt_pte_t byt_pte_encode(struct drm_device *dev,
				     dma_addr_t addr,
				     enum i915_cache_level level)
{
	gen6_gtt_pte_t pte = GEN6_PTE_VALID;
	pte |= GEN6_PTE_ADDR_ENCODE(addr);

	/* Mark the page as writeable.  Other platforms don't have a
	 * setting for read-only/writable, so this matches that behavior.
	 */
	pte |= BYT_PTE_WRITEABLE;

	if (level != I915_CACHE_NONE)
		pte |= BYT_PTE_SNOOPED_BY_CPU_CACHES;

	return pte;
}

static gen6_gtt_pte_t hsw_pte_encode(struct drm_device *dev,
				     dma_addr_t addr,
				     enum i915_cache_level level)
{
	gen6_gtt_pte_t pte = GEN6_PTE_VALID;
	pte |= GEN6_PTE_ADDR_ENCODE(addr);

	if (level != I915_CACHE_NONE)
		pte |= GEN6_PTE_CACHE_LLC;

	return pte;
}

static void gen6_write_pdes(struct i915_hw_ppgtt *ppgtt)
{
	struct drm_i915_private *dev_priv = ppgtt->dev->dev_private;
	gen6_gtt_pte_t __iomem *pd_addr;
	uint32_t pd_entry;
	int i;

	WARN_ON(ppgtt->pd_offset & 0x3f);
	pd_addr = (gen6_gtt_pte_t __iomem*)dev_priv->gtt.gsm +
		ppgtt->pd_offset / sizeof(gen6_gtt_pte_t);
	for (i = 0; i < ppgtt->num_pd_entries; i++) {
		dma_addr_t pt_addr;

		pt_addr = ppgtt->pt_dma_addr[i];
		pd_entry = GEN6_PDE_ADDR_ENCODE(pt_addr);
		pd_entry |= GEN6_PDE_VALID;

		writel(pd_entry, pd_addr + i);
	}
	readl(pd_addr);
}

static int gen6_ppgtt_enable(struct drm_device *dev)
{
	drm_i915_private_t *dev_priv = dev->dev_private;
	uint32_t pd_offset;
	struct intel_ring_buffer *ring;
	struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;
	int i;

	BUG_ON(ppgtt->pd_offset & 0x3f);

	gen6_write_pdes(ppgtt);

	pd_offset = ppgtt->pd_offset;
	pd_offset /= 64; /* in cachelines, */
	pd_offset <<= 16;

	if (INTEL_INFO(dev)->gen == 6) {
		uint32_t ecochk, gab_ctl, ecobits;

		ecobits = I915_READ(GAC_ECO_BITS);
		I915_WRITE(GAC_ECO_BITS, ecobits | ECOBITS_SNB_BIT |
					 ECOBITS_PPGTT_CACHE64B);

		gab_ctl = I915_READ(GAB_CTL);
		I915_WRITE(GAB_CTL, gab_ctl | GAB_CTL_CONT_AFTER_PAGEFAULT);

		ecochk = I915_READ(GAM_ECOCHK);
		I915_WRITE(GAM_ECOCHK, ecochk | ECOCHK_SNB_BIT |
				       ECOCHK_PPGTT_CACHE64B);
		I915_WRITE(GFX_MODE, _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));
	} else if (INTEL_INFO(dev)->gen >= 7) {
		uint32_t ecochk, ecobits;

		ecobits = I915_READ(GAC_ECO_BITS);
		I915_WRITE(GAC_ECO_BITS, ecobits | ECOBITS_PPGTT_CACHE64B);

		ecochk = I915_READ(GAM_ECOCHK);
		if (IS_HASWELL(dev)) {
			ecochk |= ECOCHK_PPGTT_WB_HSW;
		} else {
			ecochk |= ECOCHK_PPGTT_LLC_IVB;
			ecochk &= ~ECOCHK_PPGTT_GFDT_IVB;
		}
		I915_WRITE(GAM_ECOCHK, ecochk);
		/* GFX_MODE is per-ring on gen7+ */
	}

	for_each_ring(ring, dev_priv, i) {
		if (INTEL_INFO(dev)->gen >= 7)
			I915_WRITE(RING_MODE_GEN7(ring),
				   _MASKED_BIT_ENABLE(GFX_PPGTT_ENABLE));

		I915_WRITE(RING_PP_DIR_DCLV(ring), PP_DIR_DCLV_2G);
		I915_WRITE(RING_PP_DIR_BASE(ring), pd_offset);
	}
	return 0;
}

/* PPGTT support for Sandybdrige/Gen6 and later */
static void gen6_ppgtt_clear_range(struct i915_hw_ppgtt *ppgtt,
				   unsigned first_entry,
				   unsigned num_entries)
{
	gen6_gtt_pte_t *pt_vaddr, scratch_pte;
	unsigned act_pt = first_entry / I915_PPGTT_PT_ENTRIES;
	unsigned first_pte = first_entry % I915_PPGTT_PT_ENTRIES;
	unsigned last_pte, i;

	scratch_pte = ppgtt->pte_encode(ppgtt->dev,
					ppgtt->scratch_page_dma_addr,
					I915_CACHE_LLC);

	while (num_entries) {
		last_pte = first_pte + num_entries;
		if (last_pte > I915_PPGTT_PT_ENTRIES)
			last_pte = I915_PPGTT_PT_ENTRIES;

		pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pt]);

		for (i = first_pte; i < last_pte; i++)
			pt_vaddr[i] = scratch_pte;

		kunmap_atomic(pt_vaddr);

		num_entries -= last_pte - first_pte;
		first_pte = 0;
		act_pt++;
	}
}

static void gen6_ppgtt_insert_entries(struct i915_hw_ppgtt *ppgtt,
				      struct sg_table *pages,
				      unsigned first_entry,
				      enum i915_cache_level cache_level)
{
	gen6_gtt_pte_t *pt_vaddr;
	unsigned act_pt = first_entry / I915_PPGTT_PT_ENTRIES;
	unsigned act_pte = first_entry % I915_PPGTT_PT_ENTRIES;
	struct sg_page_iter sg_iter;

	pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pt]);
	for_each_sg_page(pages->sgl, &sg_iter, pages->nents, 0) {
		dma_addr_t page_addr;

		page_addr = sg_page_iter_dma_address(&sg_iter);
		pt_vaddr[act_pte] = ppgtt->pte_encode(ppgtt->dev, page_addr,
						      cache_level);
		if (++act_pte == I915_PPGTT_PT_ENTRIES) {
			kunmap_atomic(pt_vaddr);
			act_pt++;
			pt_vaddr = kmap_atomic(ppgtt->pt_pages[act_pt]);
			act_pte = 0;

		}
	}
	kunmap_atomic(pt_vaddr);
}

static void gen6_ppgtt_cleanup(struct i915_hw_ppgtt *ppgtt)
{
	int i;

	if (ppgtt->pt_dma_addr) {
		for (i = 0; i < ppgtt->num_pd_entries; i++)
			pci_unmap_page(ppgtt->dev->pdev,
				       ppgtt->pt_dma_addr[i],
				       4096, PCI_DMA_BIDIRECTIONAL);
	}

	kfree(ppgtt->pt_dma_addr);
	for (i = 0; i < ppgtt->num_pd_entries; i++)
		__free_page(ppgtt->pt_pages[i]);
	kfree(ppgtt->pt_pages);
	kfree(ppgtt);
}

static int gen6_ppgtt_init(struct i915_hw_ppgtt *ppgtt)
{
	struct drm_device *dev = ppgtt->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	unsigned first_pd_entry_in_global_pt;
	int i;
	int ret = -ENOMEM;

	/* ppgtt PDEs reside in the global gtt pagetable, which has 512*1024
	 * entries. For aliasing ppgtt support we just steal them at the end for
	 * now. */
	first_pd_entry_in_global_pt = gtt_total_entries(dev_priv->gtt);

	if (IS_HASWELL(dev)) {
		ppgtt->pte_encode = hsw_pte_encode;
	} else if (IS_VALLEYVIEW(dev)) {
		ppgtt->pte_encode = byt_pte_encode;
	} else {
		ppgtt->pte_encode = gen6_pte_encode;
	}
	ppgtt->num_pd_entries = I915_PPGTT_PD_ENTRIES;
	ppgtt->enable = gen6_ppgtt_enable;
	ppgtt->clear_range = gen6_ppgtt_clear_range;
	ppgtt->insert_entries = gen6_ppgtt_insert_entries;
	ppgtt->cleanup = gen6_ppgtt_cleanup;
	ppgtt->pt_pages = kzalloc(sizeof(struct page *)*ppgtt->num_pd_entries,
				  GFP_KERNEL);
	if (!ppgtt->pt_pages)
		return -ENOMEM;

	for (i = 0; i < ppgtt->num_pd_entries; i++) {
		ppgtt->pt_pages[i] = alloc_page(GFP_KERNEL);
		if (!ppgtt->pt_pages[i])
			goto err_pt_alloc;
	}

	ppgtt->pt_dma_addr = kzalloc(sizeof(dma_addr_t) *ppgtt->num_pd_entries,
				     GFP_KERNEL);
	if (!ppgtt->pt_dma_addr)
		goto err_pt_alloc;

	for (i = 0; i < ppgtt->num_pd_entries; i++) {
		dma_addr_t pt_addr;

		pt_addr = pci_map_page(dev->pdev, ppgtt->pt_pages[i], 0, 4096,
				       PCI_DMA_BIDIRECTIONAL);

		if (pci_dma_mapping_error(dev->pdev, pt_addr)) {
			ret = -EIO;
			goto err_pd_pin;

		}
		ppgtt->pt_dma_addr[i] = pt_addr;
	}

	ppgtt->clear_range(ppgtt, 0,
			   ppgtt->num_pd_entries*I915_PPGTT_PT_ENTRIES);

	ppgtt->pd_offset = first_pd_entry_in_global_pt * sizeof(gen6_gtt_pte_t);

	return 0;

err_pd_pin:
	if (ppgtt->pt_dma_addr) {
		for (i--; i >= 0; i--)
			pci_unmap_page(dev->pdev, ppgtt->pt_dma_addr[i],
				       4096, PCI_DMA_BIDIRECTIONAL);
	}
err_pt_alloc:
	kfree(ppgtt->pt_dma_addr);
	for (i = 0; i < ppgtt->num_pd_entries; i++) {
		if (ppgtt->pt_pages[i])
			__free_page(ppgtt->pt_pages[i]);
	}
	kfree(ppgtt->pt_pages);

	return ret;
}

static int i915_gem_init_aliasing_ppgtt(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct i915_hw_ppgtt *ppgtt;
	int ret;

	ppgtt = kzalloc(sizeof(*ppgtt), GFP_KERNEL);
	if (!ppgtt)
		return -ENOMEM;

	ppgtt->dev = dev;
	ppgtt->scratch_page_dma_addr = dev_priv->gtt.scratch_page_dma;

	if (INTEL_INFO(dev)->gen < 8)
		ret = gen6_ppgtt_init(ppgtt);
	else
		BUG();

	if (ret)
		kfree(ppgtt);
	else
		dev_priv->mm.aliasing_ppgtt = ppgtt;

	return ret;
}

void i915_gem_cleanup_aliasing_ppgtt(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct i915_hw_ppgtt *ppgtt = dev_priv->mm.aliasing_ppgtt;

	if (!ppgtt)
		return;

	ppgtt->cleanup(ppgtt);
	dev_priv->mm.aliasing_ppgtt = NULL;
}

void i915_ppgtt_bind_object(struct i915_hw_ppgtt *ppgtt,
			    struct drm_i915_gem_object *obj,
			    enum i915_cache_level cache_level)
{
	ppgtt->insert_entries(ppgtt, obj->pages,
			      obj->gtt_space->start >> PAGE_SHIFT,
			      cache_level);
}

void i915_ppgtt_unbind_object(struct i915_hw_ppgtt *ppgtt,
			      struct drm_i915_gem_object *obj)
{
	ppgtt->clear_range(ppgtt,
			   obj->gtt_space->start >> PAGE_SHIFT,
			   obj->base.size >> PAGE_SHIFT);
}

extern int intel_iommu_gfx_mapped;
/* Certain Gen5 chipsets require require idling the GPU before
 * unmapping anything from the GTT when VT-d is enabled.
 */
static inline bool needs_idle_maps(struct drm_device *dev)
{
#ifdef CONFIG_INTEL_IOMMU
	/* Query intel_iommu to see if we need the workaround. Presumably that
	 * was loaded first.
	 */
	if (IS_GEN5(dev) && IS_MOBILE(dev) && intel_iommu_gfx_mapped)
		return true;
#endif
	return false;
}

static bool do_idling(struct drm_i915_private *dev_priv)
{
	bool ret = dev_priv->mm.interruptible;

	if (unlikely(dev_priv->gtt.do_idle_maps)) {
		dev_priv->mm.interruptible = false;
		if (i915_gpu_idle(dev_priv->dev)) {
			DRM_ERROR("Couldn't idle GPU\n");
			/* Wait a bit, in hopes it avoids the hang */
			udelay(10);
		}
	}

	return ret;
}

static void undo_idling(struct drm_i915_private *dev_priv, bool interruptible)
{
	if (unlikely(dev_priv->gtt.do_idle_maps))
		dev_priv->mm.interruptible = interruptible;
}

void i915_gem_restore_gtt_mappings(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct drm_i915_gem_object *obj;

	/* First fill our portion of the GTT with scratch pages */
	dev_priv->gtt.gtt_clear_range(dev, dev_priv->gtt.start / PAGE_SIZE,
				      dev_priv->gtt.total / PAGE_SIZE);

	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
		i915_gem_clflush_object(obj);
		i915_gem_gtt_bind_object(obj, obj->cache_level);
	}

	i915_gem_chipset_flush(dev);
}

int i915_gem_gtt_prepare_object(struct drm_i915_gem_object *obj)
{
	if (obj->has_dma_mapping)
		return 0;

	if (!dma_map_sg(&obj->base.dev->pdev->dev,
			obj->pages->sgl, obj->pages->nents,
			PCI_DMA_BIDIRECTIONAL))
		return -ENOSPC;

	return 0;
}

/*
 * Binds an object into the global gtt with the specified cache level. The object
 * will be accessible to the GPU via commands whose operands reference offsets
 * within the global GTT as well as accessible by the GPU through the GMADR
 * mapped BAR (dev_priv->mm.gtt->gtt).
 */
static void gen6_ggtt_insert_entries(struct drm_device *dev,
				     struct sg_table *st,
				     unsigned int first_entry,
				     enum i915_cache_level level)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	gen6_gtt_pte_t __iomem *gtt_entries =
		(gen6_gtt_pte_t __iomem *)dev_priv->gtt.gsm + first_entry;
	int i = 0;
	struct sg_page_iter sg_iter;
	dma_addr_t addr;

	for_each_sg_page(st->sgl, &sg_iter, st->nents, 0) {
		addr = sg_page_iter_dma_address(&sg_iter);
		iowrite32(dev_priv->gtt.pte_encode(dev, addr, level),
			  &gtt_entries[i]);
		i++;
	}

	/* XXX: This serves as a posting read to make sure that the PTE has
	 * actually been updated. There is some concern that even though
	 * registers and PTEs are within the same BAR that they are potentially
	 * of NUMA access patterns. Therefore, even with the way we assume
	 * hardware should work, we must keep this posting read for paranoia.
	 */
	if (i != 0)
		WARN_ON(readl(&gtt_entries[i-1])
			!= dev_priv->gtt.pte_encode(dev, addr, level));

	/* This next bit makes the above posting read even more important. We
	 * want to flush the TLBs only after we're certain all the PTE updates
	 * have finished.
	 */
	I915_WRITE(GFX_FLSH_CNTL_GEN6, GFX_FLSH_CNTL_EN);
	POSTING_READ(GFX_FLSH_CNTL_GEN6);
}

static void gen6_ggtt_clear_range(struct drm_device *dev,
				  unsigned int first_entry,
				  unsigned int num_entries)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	gen6_gtt_pte_t scratch_pte, __iomem *gtt_base =
		(gen6_gtt_pte_t __iomem *) dev_priv->gtt.gsm + first_entry;
	const int max_entries = gtt_total_entries(dev_priv->gtt) - first_entry;
	int i;

	if (WARN(num_entries > max_entries,
		 "First entry = %d; Num entries = %d (max=%d)\n",
		 first_entry, num_entries, max_entries))
		num_entries = max_entries;

	scratch_pte = dev_priv->gtt.pte_encode(dev,
					       dev_priv->gtt.scratch_page_dma,
					       I915_CACHE_LLC);
	for (i = 0; i < num_entries; i++)
		iowrite32(scratch_pte, &gtt_base[i]);
	readl(gtt_base);
}


static void i915_ggtt_insert_entries(struct drm_device *dev,
				     struct sg_table *st,
				     unsigned int pg_start,
				     enum i915_cache_level cache_level)
{
	unsigned int flags = (cache_level == I915_CACHE_NONE) ?
		AGP_USER_MEMORY : AGP_USER_CACHED_MEMORY;

	intel_gtt_insert_sg_entries(st, pg_start, flags);

}

static void i915_ggtt_clear_range(struct drm_device *dev,
				  unsigned int first_entry,
				  unsigned int num_entries)
{
	intel_gtt_clear_range(first_entry, num_entries);
}


void i915_gem_gtt_bind_object(struct drm_i915_gem_object *obj,
			      enum i915_cache_level cache_level)
{
	struct drm_device *dev = obj->base.dev;
	struct drm_i915_private *dev_priv = dev->dev_private;

	dev_priv->gtt.gtt_insert_entries(dev, obj->pages,
					 obj->gtt_space->start >> PAGE_SHIFT,
					 cache_level);

	obj->has_global_gtt_mapping = 1;
}

void i915_gem_gtt_unbind_object(struct drm_i915_gem_object *obj)
{
	struct drm_device *dev = obj->base.dev;
	struct drm_i915_private *dev_priv = dev->dev_private;

	dev_priv->gtt.gtt_clear_range(obj->base.dev,
				      obj->gtt_space->start >> PAGE_SHIFT,
				      obj->base.size >> PAGE_SHIFT);

	obj->has_global_gtt_mapping = 0;
}

void i915_gem_gtt_finish_object(struct drm_i915_gem_object *obj)
{
	struct drm_device *dev = obj->base.dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	bool interruptible;

	interruptible = do_idling(dev_priv);

	if (!obj->has_dma_mapping)
		dma_unmap_sg(&dev->pdev->dev,
			     obj->pages->sgl, obj->pages->nents,
			     PCI_DMA_BIDIRECTIONAL);

	undo_idling(dev_priv, interruptible);
}

static void i915_gtt_color_adjust(struct drm_mm_node *node,
				  unsigned long color,
				  unsigned long *start,
				  unsigned long *end)
{
	if (node->color != color)
		*start += 4096;

	if (!list_empty(&node->node_list)) {
		node = list_entry(node->node_list.next,
				  struct drm_mm_node,
				  node_list);
		if (node->allocated && node->color != color)
			*end -= 4096;
	}
}
void i915_gem_setup_global_gtt(struct drm_device *dev,
			       unsigned long start,
			       unsigned long mappable_end,
			       unsigned long end)
{
	/* Let GEM Manage all of the aperture.
	 *
	 * However, leave one page at the end still bound to the scratch page.
	 * There are a number of places where the hardware apparently prefetches
	 * past the end of the object, and we've seen multiple hangs with the
	 * GPU head pointer stuck in a batchbuffer bound at the last page of the
	 * aperture.  One page should be enough to keep any prefetching inside
	 * of the aperture.
	 */
	drm_i915_private_t *dev_priv = dev->dev_private;
	struct drm_mm_node *entry;
	struct drm_i915_gem_object *obj;
	unsigned long hole_start, hole_end;

	BUG_ON(mappable_end > end);

	/* Subtract the guard page ... */
	drm_mm_init(&dev_priv->mm.gtt_space, start, end - start - PAGE_SIZE);
	if (!HAS_LLC(dev))
		dev_priv->mm.gtt_space.color_adjust = i915_gtt_color_adjust;

	/* Mark any preallocated objects as occupied */
	list_for_each_entry(obj, &dev_priv->mm.bound_list, global_list) {
		DRM_DEBUG_KMS("reserving preallocated space: %x + %zx\n",
			      obj->gtt_offset, obj->base.size);

		BUG_ON(obj->gtt_space != I915_GTT_RESERVED);
		obj->gtt_space = drm_mm_create_block(&dev_priv->mm.gtt_space,
						     obj->gtt_offset,
						     obj->base.size,
						     false);
		obj->has_global_gtt_mapping = 1;
	}

	dev_priv->gtt.start = start;
	dev_priv->gtt.total = end - start;

	/* Clear any non-preallocated blocks */
	drm_mm_for_each_hole(entry, &dev_priv->mm.gtt_space,
			     hole_start, hole_end) {
		DRM_DEBUG_KMS("clearing unused GTT space: [%lx, %lx]\n",
			      hole_start, hole_end);
		dev_priv->gtt.gtt_clear_range(dev, hole_start / PAGE_SIZE,
					      (hole_end-hole_start) / PAGE_SIZE);
	}

	/* And finally clear the reserved guard page */
	dev_priv->gtt.gtt_clear_range(dev, end / PAGE_SIZE - 1, 1);
}

static bool
intel_enable_ppgtt(struct drm_device *dev)
{
	if (i915_enable_ppgtt >= 0)
		return i915_enable_ppgtt;

#ifdef CONFIG_INTEL_IOMMU
	/* Disable ppgtt on SNB if VT-d is on. */
	if (INTEL_INFO(dev)->gen == 6 && intel_iommu_gfx_mapped)
		return false;
#endif

	return true;
}

void i915_gem_init_global_gtt(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	unsigned long gtt_size, mappable_size;

	gtt_size = dev_priv->gtt.total;
	mappable_size = dev_priv->gtt.mappable_end;

	if (intel_enable_ppgtt(dev) && HAS_ALIASING_PPGTT(dev)) {
		int ret;

		if (INTEL_INFO(dev)->gen <= 7) {
			/* PPGTT pdes are stolen from global gtt ptes, so shrink the
			 * aperture accordingly when using aliasing ppgtt. */
			gtt_size -= I915_PPGTT_PD_ENTRIES*PAGE_SIZE;
		}

		i915_gem_setup_global_gtt(dev, 0, mappable_size, gtt_size);

		ret = i915_gem_init_aliasing_ppgtt(dev);
		if (!ret)
			return;

		DRM_ERROR("Aliased PPGTT setup failed %d\n", ret);
		drm_mm_takedown(&dev_priv->mm.gtt_space);
		gtt_size += I915_PPGTT_PD_ENTRIES*PAGE_SIZE;
	}
	i915_gem_setup_global_gtt(dev, 0, mappable_size, gtt_size);
}

static int setup_scratch_page(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct page *page;
	dma_addr_t dma_addr;

	page = alloc_page(GFP_KERNEL | GFP_DMA32 | __GFP_ZERO);
	if (page == NULL)
		return -ENOMEM;
	get_page(page);
	set_pages_uc(page, 1);

#ifdef CONFIG_INTEL_IOMMU
	dma_addr = pci_map_page(dev->pdev, page, 0, PAGE_SIZE,
				PCI_DMA_BIDIRECTIONAL);
	if (pci_dma_mapping_error(dev->pdev, dma_addr))
		return -EINVAL;
#else
	dma_addr = page_to_phys(page);
#endif
	dev_priv->gtt.scratch_page = page;
	dev_priv->gtt.scratch_page_dma = dma_addr;

	return 0;
}

static void teardown_scratch_page(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	set_pages_wb(dev_priv->gtt.scratch_page, 1);
	pci_unmap_page(dev->pdev, dev_priv->gtt.scratch_page_dma,
		       PAGE_SIZE, PCI_DMA_BIDIRECTIONAL);
	put_page(dev_priv->gtt.scratch_page);
	__free_page(dev_priv->gtt.scratch_page);
}

static inline unsigned int gen6_get_total_gtt_size(u16 snb_gmch_ctl)
{
	snb_gmch_ctl >>= SNB_GMCH_GGMS_SHIFT;
	snb_gmch_ctl &= SNB_GMCH_GGMS_MASK;
	return snb_gmch_ctl << 20;
}

static inline size_t gen6_get_stolen_size(u16 snb_gmch_ctl)
{
	snb_gmch_ctl >>= SNB_GMCH_GMS_SHIFT;
	snb_gmch_ctl &= SNB_GMCH_GMS_MASK;
	return snb_gmch_ctl << 25; /* 32 MB units */
}

static int gen6_gmch_probe(struct drm_device *dev,
			   size_t *gtt_total,
			   size_t *stolen,
			   phys_addr_t *mappable_base,
			   unsigned long *mappable_end)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	phys_addr_t gtt_bus_addr;
	unsigned int gtt_size;
	u16 snb_gmch_ctl;
	int ret;

	*mappable_base = pci_resource_start(dev->pdev, 2);
	*mappable_end = pci_resource_len(dev->pdev, 2);

	/* 64/512MB is the current min/max we actually know of, but this is just
	 * a coarse sanity check.
	 */
	if ((*mappable_end < (64<<20) || (*mappable_end > (512<<20)))) {
		DRM_ERROR("Unknown GMADR size (%lx)\n",
			  dev_priv->gtt.mappable_end);
		return -ENXIO;
	}

	if (!pci_set_dma_mask(dev->pdev, DMA_BIT_MASK(40)))
		pci_set_consistent_dma_mask(dev->pdev, DMA_BIT_MASK(40));
	pci_read_config_word(dev->pdev, SNB_GMCH_CTRL, &snb_gmch_ctl);
	gtt_size = gen6_get_total_gtt_size(snb_gmch_ctl);

	*stolen = gen6_get_stolen_size(snb_gmch_ctl);
	*gtt_total = (gtt_size / sizeof(gen6_gtt_pte_t)) << PAGE_SHIFT;

	/* For Modern GENs the PTEs and register space are split in the BAR */
	gtt_bus_addr = pci_resource_start(dev->pdev, 0) +
		(pci_resource_len(dev->pdev, 0) / 2);

	dev_priv->gtt.gsm = ioremap_wc(gtt_bus_addr, gtt_size);
	if (!dev_priv->gtt.gsm) {
		DRM_ERROR("Failed to map the gtt page table\n");
		return -ENOMEM;
	}

	ret = setup_scratch_page(dev);
	if (ret)
		DRM_ERROR("Scratch setup failed\n");

	dev_priv->gtt.gtt_clear_range = gen6_ggtt_clear_range;
	dev_priv->gtt.gtt_insert_entries = gen6_ggtt_insert_entries;

	return ret;
}

static void gen6_gmch_remove(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	iounmap(dev_priv->gtt.gsm);
	teardown_scratch_page(dev_priv->dev);
}

static int i915_gmch_probe(struct drm_device *dev,
			   size_t *gtt_total,
			   size_t *stolen,
			   phys_addr_t *mappable_base,
			   unsigned long *mappable_end)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	int ret;

	ret = intel_gmch_probe(dev_priv->bridge_dev, dev_priv->dev->pdev, NULL);
	if (!ret) {
		DRM_ERROR("failed to set up gmch\n");
		return -EIO;
	}

	intel_gtt_get(gtt_total, stolen, mappable_base, mappable_end);

	dev_priv->gtt.do_idle_maps = needs_idle_maps(dev_priv->dev);
	dev_priv->gtt.gtt_clear_range = i915_ggtt_clear_range;
	dev_priv->gtt.gtt_insert_entries = i915_ggtt_insert_entries;

	return 0;
}

static void i915_gmch_remove(struct drm_device *dev)
{
	intel_gmch_remove();
}

int i915_gem_gtt_init(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct i915_gtt *gtt = &dev_priv->gtt;
	int ret;

	if (INTEL_INFO(dev)->gen <= 5) {
		dev_priv->gtt.gtt_probe = i915_gmch_probe;
		dev_priv->gtt.gtt_remove = i915_gmch_remove;
	} else {
		dev_priv->gtt.gtt_probe = gen6_gmch_probe;
		dev_priv->gtt.gtt_remove = gen6_gmch_remove;
		if (IS_HASWELL(dev)) {
			dev_priv->gtt.pte_encode = hsw_pte_encode;
		} else if (IS_VALLEYVIEW(dev)) {
			dev_priv->gtt.pte_encode = byt_pte_encode;
		} else {
			dev_priv->gtt.pte_encode = gen6_pte_encode;
		}
	}

	ret = dev_priv->gtt.gtt_probe(dev, &dev_priv->gtt.total,
				     &dev_priv->gtt.stolen_size,
				     &gtt->mappable_base,
				     &gtt->mappable_end);
	if (ret)
		return ret;

	/* GMADR is the PCI mmio aperture into the global GTT. */
	DRM_INFO("Memory usable by graphics device = %zdM\n",
		 dev_priv->gtt.total >> 20);
	DRM_DEBUG_DRIVER("GMADR size = %ldM\n",
			 dev_priv->gtt.mappable_end >> 20);
	DRM_DEBUG_DRIVER("GTT stolen size = %zdM\n",
			 dev_priv->gtt.stolen_size >> 20);

	return 0;
}