1 // SPDX-License-Identifier:	GPL-2.0
2 /* Copyright 2019 Linaro, Ltd, Rob Herring <robh@kernel.org> */
3 
4 #include <drm/panfrost_drm.h>
5 
6 #include <linux/atomic.h>
7 #include <linux/bitfield.h>
8 #include <linux/delay.h>
9 #include <linux/dma-mapping.h>
10 #include <linux/interrupt.h>
11 #include <linux/io.h>
12 #include <linux/iopoll.h>
13 #include <linux/io-pgtable.h>
14 #include <linux/iommu.h>
15 #include <linux/platform_device.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/shmem_fs.h>
18 #include <linux/sizes.h>
19 
20 #include "panfrost_device.h"
21 #include "panfrost_mmu.h"
22 #include "panfrost_gem.h"
23 #include "panfrost_features.h"
24 #include "panfrost_regs.h"
25 
26 #define mmu_write(dev, reg, data) writel(data, dev->iomem + reg)
27 #define mmu_read(dev, reg) readl(dev->iomem + reg)
28 
29 static int wait_ready(struct panfrost_device *pfdev, u32 as_nr)
30 {
31 	int ret;
32 	u32 val;
33 
34 	/* Wait for the MMU status to indicate there is no active command, in
35 	 * case one is pending. */
36 	ret = readl_relaxed_poll_timeout_atomic(pfdev->iomem + AS_STATUS(as_nr),
37 		val, !(val & AS_STATUS_AS_ACTIVE), 10, 100000);
38 
39 	if (ret) {
40 		/* The GPU hung, let's trigger a reset */
41 		panfrost_device_schedule_reset(pfdev);
42 		dev_err(pfdev->dev, "AS_ACTIVE bit stuck\n");
43 	}
44 
45 	return ret;
46 }
47 
48 static int write_cmd(struct panfrost_device *pfdev, u32 as_nr, u32 cmd)
49 {
50 	int status;
51 
52 	/* write AS_COMMAND when MMU is ready to accept another command */
53 	status = wait_ready(pfdev, as_nr);
54 	if (!status)
55 		mmu_write(pfdev, AS_COMMAND(as_nr), cmd);
56 
57 	return status;
58 }
59 
60 static void lock_region(struct panfrost_device *pfdev, u32 as_nr,
61 			u64 iova, size_t size)
62 {
63 	u8 region_width;
64 	u64 region = iova & PAGE_MASK;
65 	/*
66 	 * fls returns:
67 	 * 1 .. 32
68 	 *
69 	 * 10 + fls(num_pages)
70 	 * results in the range (11 .. 42)
71 	 */
72 
73 	size = round_up(size, PAGE_SIZE);
74 
75 	region_width = 10 + fls(size >> PAGE_SHIFT);
76 	if ((size >> PAGE_SHIFT) != (1ul << (region_width - 11))) {
77 		/* not pow2, so must go up to the next pow2 */
78 		region_width += 1;
79 	}
80 	region |= region_width;
81 
82 	/* Lock the region that needs to be updated */
83 	mmu_write(pfdev, AS_LOCKADDR_LO(as_nr), region & 0xFFFFFFFFUL);
84 	mmu_write(pfdev, AS_LOCKADDR_HI(as_nr), (region >> 32) & 0xFFFFFFFFUL);
85 	write_cmd(pfdev, as_nr, AS_COMMAND_LOCK);
86 }
87 
88 
89 static int mmu_hw_do_operation_locked(struct panfrost_device *pfdev, int as_nr,
90 				      u64 iova, size_t size, u32 op)
91 {
92 	if (as_nr < 0)
93 		return 0;
94 
95 	if (op != AS_COMMAND_UNLOCK)
96 		lock_region(pfdev, as_nr, iova, size);
97 
98 	/* Run the MMU operation */
99 	write_cmd(pfdev, as_nr, op);
100 
101 	/* Wait for the flush to complete */
102 	return wait_ready(pfdev, as_nr);
103 }
104 
105 static int mmu_hw_do_operation(struct panfrost_device *pfdev,
106 			       struct panfrost_mmu *mmu,
107 			       u64 iova, size_t size, u32 op)
108 {
109 	int ret;
110 
111 	spin_lock(&pfdev->as_lock);
112 	ret = mmu_hw_do_operation_locked(pfdev, mmu->as, iova, size, op);
113 	spin_unlock(&pfdev->as_lock);
114 	return ret;
115 }
116 
117 static void panfrost_mmu_enable(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
118 {
119 	int as_nr = mmu->as;
120 	struct io_pgtable_cfg *cfg = &mmu->pgtbl_cfg;
121 	u64 transtab = cfg->arm_mali_lpae_cfg.transtab;
122 	u64 memattr = cfg->arm_mali_lpae_cfg.memattr;
123 
124 	mmu_hw_do_operation_locked(pfdev, as_nr, 0, ~0UL, AS_COMMAND_FLUSH_MEM);
125 
126 	mmu_write(pfdev, AS_TRANSTAB_LO(as_nr), transtab & 0xffffffffUL);
127 	mmu_write(pfdev, AS_TRANSTAB_HI(as_nr), transtab >> 32);
128 
129 	/* Need to revisit mem attrs.
130 	 * NC is the default, Mali driver is inner WT.
131 	 */
132 	mmu_write(pfdev, AS_MEMATTR_LO(as_nr), memattr & 0xffffffffUL);
133 	mmu_write(pfdev, AS_MEMATTR_HI(as_nr), memattr >> 32);
134 
135 	write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
136 }
137 
138 static void panfrost_mmu_disable(struct panfrost_device *pfdev, u32 as_nr)
139 {
140 	mmu_hw_do_operation_locked(pfdev, as_nr, 0, ~0UL, AS_COMMAND_FLUSH_MEM);
141 
142 	mmu_write(pfdev, AS_TRANSTAB_LO(as_nr), 0);
143 	mmu_write(pfdev, AS_TRANSTAB_HI(as_nr), 0);
144 
145 	mmu_write(pfdev, AS_MEMATTR_LO(as_nr), 0);
146 	mmu_write(pfdev, AS_MEMATTR_HI(as_nr), 0);
147 
148 	write_cmd(pfdev, as_nr, AS_COMMAND_UPDATE);
149 }
150 
151 u32 panfrost_mmu_as_get(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
152 {
153 	int as;
154 
155 	spin_lock(&pfdev->as_lock);
156 
157 	as = mmu->as;
158 	if (as >= 0) {
159 		int en = atomic_inc_return(&mmu->as_count);
160 		u32 mask = BIT(as) | BIT(16 + as);
161 
162 		/*
163 		 * AS can be retained by active jobs or a perfcnt context,
164 		 * hence the '+ 1' here.
165 		 */
166 		WARN_ON(en >= (NUM_JOB_SLOTS + 1));
167 
168 		list_move(&mmu->list, &pfdev->as_lru_list);
169 
170 		if (pfdev->as_faulty_mask & mask) {
171 			/* Unhandled pagefault on this AS, the MMU was
172 			 * disabled. We need to re-enable the MMU after
173 			 * clearing+unmasking the AS interrupts.
174 			 */
175 			mmu_write(pfdev, MMU_INT_CLEAR, mask);
176 			mmu_write(pfdev, MMU_INT_MASK, ~pfdev->as_faulty_mask);
177 			pfdev->as_faulty_mask &= ~mask;
178 			panfrost_mmu_enable(pfdev, mmu);
179 		}
180 
181 		goto out;
182 	}
183 
184 	/* Check for a free AS */
185 	as = ffz(pfdev->as_alloc_mask);
186 	if (!(BIT(as) & pfdev->features.as_present)) {
187 		struct panfrost_mmu *lru_mmu;
188 
189 		list_for_each_entry_reverse(lru_mmu, &pfdev->as_lru_list, list) {
190 			if (!atomic_read(&lru_mmu->as_count))
191 				break;
192 		}
193 		WARN_ON(&lru_mmu->list == &pfdev->as_lru_list);
194 
195 		list_del_init(&lru_mmu->list);
196 		as = lru_mmu->as;
197 
198 		WARN_ON(as < 0);
199 		lru_mmu->as = -1;
200 	}
201 
202 	/* Assign the free or reclaimed AS to the FD */
203 	mmu->as = as;
204 	set_bit(as, &pfdev->as_alloc_mask);
205 	atomic_set(&mmu->as_count, 1);
206 	list_add(&mmu->list, &pfdev->as_lru_list);
207 
208 	dev_dbg(pfdev->dev, "Assigned AS%d to mmu %p, alloc_mask=%lx", as, mmu, pfdev->as_alloc_mask);
209 
210 	panfrost_mmu_enable(pfdev, mmu);
211 
212 out:
213 	spin_unlock(&pfdev->as_lock);
214 	return as;
215 }
216 
217 void panfrost_mmu_as_put(struct panfrost_device *pfdev, struct panfrost_mmu *mmu)
218 {
219 	atomic_dec(&mmu->as_count);
220 	WARN_ON(atomic_read(&mmu->as_count) < 0);
221 }
222 
223 void panfrost_mmu_reset(struct panfrost_device *pfdev)
224 {
225 	struct panfrost_mmu *mmu, *mmu_tmp;
226 
227 	spin_lock(&pfdev->as_lock);
228 
229 	pfdev->as_alloc_mask = 0;
230 	pfdev->as_faulty_mask = 0;
231 
232 	list_for_each_entry_safe(mmu, mmu_tmp, &pfdev->as_lru_list, list) {
233 		mmu->as = -1;
234 		atomic_set(&mmu->as_count, 0);
235 		list_del_init(&mmu->list);
236 	}
237 
238 	spin_unlock(&pfdev->as_lock);
239 
240 	mmu_write(pfdev, MMU_INT_CLEAR, ~0);
241 	mmu_write(pfdev, MMU_INT_MASK, ~0);
242 }
243 
244 static size_t get_pgsize(u64 addr, size_t size)
245 {
246 	if (addr & (SZ_2M - 1) || size < SZ_2M)
247 		return SZ_4K;
248 
249 	return SZ_2M;
250 }
251 
252 static void panfrost_mmu_flush_range(struct panfrost_device *pfdev,
253 				     struct panfrost_mmu *mmu,
254 				     u64 iova, size_t size)
255 {
256 	if (mmu->as < 0)
257 		return;
258 
259 	pm_runtime_get_noresume(pfdev->dev);
260 
261 	/* Flush the PTs only if we're already awake */
262 	if (pm_runtime_active(pfdev->dev))
263 		mmu_hw_do_operation(pfdev, mmu, iova, size, AS_COMMAND_FLUSH_PT);
264 
265 	pm_runtime_put_sync_autosuspend(pfdev->dev);
266 }
267 
268 static int mmu_map_sg(struct panfrost_device *pfdev, struct panfrost_mmu *mmu,
269 		      u64 iova, int prot, struct sg_table *sgt)
270 {
271 	unsigned int count;
272 	struct scatterlist *sgl;
273 	struct io_pgtable_ops *ops = mmu->pgtbl_ops;
274 	u64 start_iova = iova;
275 
276 	for_each_sgtable_dma_sg(sgt, sgl, count) {
277 		unsigned long paddr = sg_dma_address(sgl);
278 		size_t len = sg_dma_len(sgl);
279 
280 		dev_dbg(pfdev->dev, "map: as=%d, iova=%llx, paddr=%lx, len=%zx", mmu->as, iova, paddr, len);
281 
282 		while (len) {
283 			size_t pgsize = get_pgsize(iova | paddr, len);
284 
285 			ops->map(ops, iova, paddr, pgsize, prot, GFP_KERNEL);
286 			iova += pgsize;
287 			paddr += pgsize;
288 			len -= pgsize;
289 		}
290 	}
291 
292 	panfrost_mmu_flush_range(pfdev, mmu, start_iova, iova - start_iova);
293 
294 	return 0;
295 }
296 
297 int panfrost_mmu_map(struct panfrost_gem_mapping *mapping)
298 {
299 	struct panfrost_gem_object *bo = mapping->obj;
300 	struct drm_gem_object *obj = &bo->base.base;
301 	struct panfrost_device *pfdev = to_panfrost_device(obj->dev);
302 	struct sg_table *sgt;
303 	int prot = IOMMU_READ | IOMMU_WRITE;
304 
305 	if (WARN_ON(mapping->active))
306 		return 0;
307 
308 	if (bo->noexec)
309 		prot |= IOMMU_NOEXEC;
310 
311 	sgt = drm_gem_shmem_get_pages_sgt(obj);
312 	if (WARN_ON(IS_ERR(sgt)))
313 		return PTR_ERR(sgt);
314 
315 	mmu_map_sg(pfdev, mapping->mmu, mapping->mmnode.start << PAGE_SHIFT,
316 		   prot, sgt);
317 	mapping->active = true;
318 
319 	return 0;
320 }
321 
322 void panfrost_mmu_unmap(struct panfrost_gem_mapping *mapping)
323 {
324 	struct panfrost_gem_object *bo = mapping->obj;
325 	struct drm_gem_object *obj = &bo->base.base;
326 	struct panfrost_device *pfdev = to_panfrost_device(obj->dev);
327 	struct io_pgtable_ops *ops = mapping->mmu->pgtbl_ops;
328 	u64 iova = mapping->mmnode.start << PAGE_SHIFT;
329 	size_t len = mapping->mmnode.size << PAGE_SHIFT;
330 	size_t unmapped_len = 0;
331 
332 	if (WARN_ON(!mapping->active))
333 		return;
334 
335 	dev_dbg(pfdev->dev, "unmap: as=%d, iova=%llx, len=%zx",
336 		mapping->mmu->as, iova, len);
337 
338 	while (unmapped_len < len) {
339 		size_t unmapped_page;
340 		size_t pgsize = get_pgsize(iova, len - unmapped_len);
341 
342 		if (ops->iova_to_phys(ops, iova)) {
343 			unmapped_page = ops->unmap(ops, iova, pgsize, NULL);
344 			WARN_ON(unmapped_page != pgsize);
345 		}
346 		iova += pgsize;
347 		unmapped_len += pgsize;
348 	}
349 
350 	panfrost_mmu_flush_range(pfdev, mapping->mmu,
351 				 mapping->mmnode.start << PAGE_SHIFT, len);
352 	mapping->active = false;
353 }
354 
355 static void mmu_tlb_inv_context_s1(void *cookie)
356 {}
357 
358 static void mmu_tlb_sync_context(void *cookie)
359 {
360 	//struct panfrost_mmu *mmu = cookie;
361 	// TODO: Wait 1000 GPU cycles for HW_ISSUE_6367/T60X
362 }
363 
364 static void mmu_tlb_flush_walk(unsigned long iova, size_t size, size_t granule,
365 			       void *cookie)
366 {
367 	mmu_tlb_sync_context(cookie);
368 }
369 
370 static const struct iommu_flush_ops mmu_tlb_ops = {
371 	.tlb_flush_all	= mmu_tlb_inv_context_s1,
372 	.tlb_flush_walk = mmu_tlb_flush_walk,
373 };
374 
375 static struct panfrost_gem_mapping *
376 addr_to_mapping(struct panfrost_device *pfdev, int as, u64 addr)
377 {
378 	struct panfrost_gem_mapping *mapping = NULL;
379 	struct drm_mm_node *node;
380 	u64 offset = addr >> PAGE_SHIFT;
381 	struct panfrost_mmu *mmu;
382 
383 	spin_lock(&pfdev->as_lock);
384 	list_for_each_entry(mmu, &pfdev->as_lru_list, list) {
385 		if (as == mmu->as)
386 			goto found_mmu;
387 	}
388 	goto out;
389 
390 found_mmu:
391 
392 	spin_lock(&mmu->mm_lock);
393 
394 	drm_mm_for_each_node(node, &mmu->mm) {
395 		if (offset >= node->start &&
396 		    offset < (node->start + node->size)) {
397 			mapping = drm_mm_node_to_panfrost_mapping(node);
398 
399 			kref_get(&mapping->refcount);
400 			break;
401 		}
402 	}
403 
404 	spin_unlock(&mmu->mm_lock);
405 out:
406 	spin_unlock(&pfdev->as_lock);
407 	return mapping;
408 }
409 
410 #define NUM_FAULT_PAGES (SZ_2M / PAGE_SIZE)
411 
412 static int panfrost_mmu_map_fault_addr(struct panfrost_device *pfdev, int as,
413 				       u64 addr)
414 {
415 	int ret, i;
416 	struct panfrost_gem_mapping *bomapping;
417 	struct panfrost_gem_object *bo;
418 	struct address_space *mapping;
419 	pgoff_t page_offset;
420 	struct sg_table *sgt;
421 	struct page **pages;
422 
423 	bomapping = addr_to_mapping(pfdev, as, addr);
424 	if (!bomapping)
425 		return -ENOENT;
426 
427 	bo = bomapping->obj;
428 	if (!bo->is_heap) {
429 		dev_WARN(pfdev->dev, "matching BO is not heap type (GPU VA = %llx)",
430 			 bomapping->mmnode.start << PAGE_SHIFT);
431 		ret = -EINVAL;
432 		goto err_bo;
433 	}
434 	WARN_ON(bomapping->mmu->as != as);
435 
436 	/* Assume 2MB alignment and size multiple */
437 	addr &= ~((u64)SZ_2M - 1);
438 	page_offset = addr >> PAGE_SHIFT;
439 	page_offset -= bomapping->mmnode.start;
440 
441 	mutex_lock(&bo->base.pages_lock);
442 
443 	if (!bo->base.pages) {
444 		bo->sgts = kvmalloc_array(bo->base.base.size / SZ_2M,
445 				     sizeof(struct sg_table), GFP_KERNEL | __GFP_ZERO);
446 		if (!bo->sgts) {
447 			mutex_unlock(&bo->base.pages_lock);
448 			ret = -ENOMEM;
449 			goto err_bo;
450 		}
451 
452 		pages = kvmalloc_array(bo->base.base.size >> PAGE_SHIFT,
453 				       sizeof(struct page *), GFP_KERNEL | __GFP_ZERO);
454 		if (!pages) {
455 			kvfree(bo->sgts);
456 			bo->sgts = NULL;
457 			mutex_unlock(&bo->base.pages_lock);
458 			ret = -ENOMEM;
459 			goto err_bo;
460 		}
461 		bo->base.pages = pages;
462 		bo->base.pages_use_count = 1;
463 	} else {
464 		pages = bo->base.pages;
465 		if (pages[page_offset]) {
466 			/* Pages are already mapped, bail out. */
467 			mutex_unlock(&bo->base.pages_lock);
468 			goto out;
469 		}
470 	}
471 
472 	mapping = bo->base.base.filp->f_mapping;
473 	mapping_set_unevictable(mapping);
474 
475 	for (i = page_offset; i < page_offset + NUM_FAULT_PAGES; i++) {
476 		pages[i] = shmem_read_mapping_page(mapping, i);
477 		if (IS_ERR(pages[i])) {
478 			mutex_unlock(&bo->base.pages_lock);
479 			ret = PTR_ERR(pages[i]);
480 			goto err_pages;
481 		}
482 	}
483 
484 	mutex_unlock(&bo->base.pages_lock);
485 
486 	sgt = &bo->sgts[page_offset / (SZ_2M / PAGE_SIZE)];
487 	ret = sg_alloc_table_from_pages(sgt, pages + page_offset,
488 					NUM_FAULT_PAGES, 0, SZ_2M, GFP_KERNEL);
489 	if (ret)
490 		goto err_pages;
491 
492 	ret = dma_map_sgtable(pfdev->dev, sgt, DMA_BIDIRECTIONAL, 0);
493 	if (ret)
494 		goto err_map;
495 
496 	mmu_map_sg(pfdev, bomapping->mmu, addr,
497 		   IOMMU_WRITE | IOMMU_READ | IOMMU_NOEXEC, sgt);
498 
499 	bomapping->active = true;
500 
501 	dev_dbg(pfdev->dev, "mapped page fault @ AS%d %llx", as, addr);
502 
503 out:
504 	panfrost_gem_mapping_put(bomapping);
505 
506 	return 0;
507 
508 err_map:
509 	sg_free_table(sgt);
510 err_pages:
511 	drm_gem_shmem_put_pages(&bo->base);
512 err_bo:
513 	drm_gem_object_put(&bo->base.base);
514 	return ret;
515 }
516 
517 static void panfrost_mmu_release_ctx(struct kref *kref)
518 {
519 	struct panfrost_mmu *mmu = container_of(kref, struct panfrost_mmu,
520 						refcount);
521 	struct panfrost_device *pfdev = mmu->pfdev;
522 
523 	spin_lock(&pfdev->as_lock);
524 	if (mmu->as >= 0) {
525 		pm_runtime_get_noresume(pfdev->dev);
526 		if (pm_runtime_active(pfdev->dev))
527 			panfrost_mmu_disable(pfdev, mmu->as);
528 		pm_runtime_put_autosuspend(pfdev->dev);
529 
530 		clear_bit(mmu->as, &pfdev->as_alloc_mask);
531 		clear_bit(mmu->as, &pfdev->as_in_use_mask);
532 		list_del(&mmu->list);
533 	}
534 	spin_unlock(&pfdev->as_lock);
535 
536 	free_io_pgtable_ops(mmu->pgtbl_ops);
537 	drm_mm_takedown(&mmu->mm);
538 	kfree(mmu);
539 }
540 
541 void panfrost_mmu_ctx_put(struct panfrost_mmu *mmu)
542 {
543 	kref_put(&mmu->refcount, panfrost_mmu_release_ctx);
544 }
545 
546 struct panfrost_mmu *panfrost_mmu_ctx_get(struct panfrost_mmu *mmu)
547 {
548 	kref_get(&mmu->refcount);
549 
550 	return mmu;
551 }
552 
553 #define PFN_4G		(SZ_4G >> PAGE_SHIFT)
554 #define PFN_4G_MASK	(PFN_4G - 1)
555 #define PFN_16M		(SZ_16M >> PAGE_SHIFT)
556 
557 static void panfrost_drm_mm_color_adjust(const struct drm_mm_node *node,
558 					 unsigned long color,
559 					 u64 *start, u64 *end)
560 {
561 	/* Executable buffers can't start or end on a 4GB boundary */
562 	if (!(color & PANFROST_BO_NOEXEC)) {
563 		u64 next_seg;
564 
565 		if ((*start & PFN_4G_MASK) == 0)
566 			(*start)++;
567 
568 		if ((*end & PFN_4G_MASK) == 0)
569 			(*end)--;
570 
571 		next_seg = ALIGN(*start, PFN_4G);
572 		if (next_seg - *start <= PFN_16M)
573 			*start = next_seg + 1;
574 
575 		*end = min(*end, ALIGN(*start, PFN_4G) - 1);
576 	}
577 }
578 
579 struct panfrost_mmu *panfrost_mmu_ctx_create(struct panfrost_device *pfdev)
580 {
581 	struct panfrost_mmu *mmu;
582 
583 	mmu = kzalloc(sizeof(*mmu), GFP_KERNEL);
584 	if (!mmu)
585 		return ERR_PTR(-ENOMEM);
586 
587 	mmu->pfdev = pfdev;
588 	spin_lock_init(&mmu->mm_lock);
589 
590 	/* 4G enough for now. can be 48-bit */
591 	drm_mm_init(&mmu->mm, SZ_32M >> PAGE_SHIFT, (SZ_4G - SZ_32M) >> PAGE_SHIFT);
592 	mmu->mm.color_adjust = panfrost_drm_mm_color_adjust;
593 
594 	INIT_LIST_HEAD(&mmu->list);
595 	mmu->as = -1;
596 
597 	mmu->pgtbl_cfg = (struct io_pgtable_cfg) {
598 		.pgsize_bitmap	= SZ_4K | SZ_2M,
599 		.ias		= FIELD_GET(0xff, pfdev->features.mmu_features),
600 		.oas		= FIELD_GET(0xff00, pfdev->features.mmu_features),
601 		.coherent_walk	= pfdev->coherent,
602 		.tlb		= &mmu_tlb_ops,
603 		.iommu_dev	= pfdev->dev,
604 	};
605 
606 	mmu->pgtbl_ops = alloc_io_pgtable_ops(ARM_MALI_LPAE, &mmu->pgtbl_cfg,
607 					      mmu);
608 	if (!mmu->pgtbl_ops) {
609 		kfree(mmu);
610 		return ERR_PTR(-EINVAL);
611 	}
612 
613 	kref_init(&mmu->refcount);
614 
615 	return mmu;
616 }
617 
618 static const char *access_type_name(struct panfrost_device *pfdev,
619 		u32 fault_status)
620 {
621 	switch (fault_status & AS_FAULTSTATUS_ACCESS_TYPE_MASK) {
622 	case AS_FAULTSTATUS_ACCESS_TYPE_ATOMIC:
623 		if (panfrost_has_hw_feature(pfdev, HW_FEATURE_AARCH64_MMU))
624 			return "ATOMIC";
625 		else
626 			return "UNKNOWN";
627 	case AS_FAULTSTATUS_ACCESS_TYPE_READ:
628 		return "READ";
629 	case AS_FAULTSTATUS_ACCESS_TYPE_WRITE:
630 		return "WRITE";
631 	case AS_FAULTSTATUS_ACCESS_TYPE_EX:
632 		return "EXECUTE";
633 	default:
634 		WARN_ON(1);
635 		return NULL;
636 	}
637 }
638 
639 static irqreturn_t panfrost_mmu_irq_handler(int irq, void *data)
640 {
641 	struct panfrost_device *pfdev = data;
642 
643 	if (!mmu_read(pfdev, MMU_INT_STAT))
644 		return IRQ_NONE;
645 
646 	mmu_write(pfdev, MMU_INT_MASK, 0);
647 	return IRQ_WAKE_THREAD;
648 }
649 
650 static irqreturn_t panfrost_mmu_irq_handler_thread(int irq, void *data)
651 {
652 	struct panfrost_device *pfdev = data;
653 	u32 status = mmu_read(pfdev, MMU_INT_RAWSTAT);
654 	int ret;
655 
656 	while (status) {
657 		u32 as = ffs(status | (status >> 16)) - 1;
658 		u32 mask = BIT(as) | BIT(as + 16);
659 		u64 addr;
660 		u32 fault_status;
661 		u32 exception_type;
662 		u32 access_type;
663 		u32 source_id;
664 
665 		fault_status = mmu_read(pfdev, AS_FAULTSTATUS(as));
666 		addr = mmu_read(pfdev, AS_FAULTADDRESS_LO(as));
667 		addr |= (u64)mmu_read(pfdev, AS_FAULTADDRESS_HI(as)) << 32;
668 
669 		/* decode the fault status */
670 		exception_type = fault_status & 0xFF;
671 		access_type = (fault_status >> 8) & 0x3;
672 		source_id = (fault_status >> 16);
673 
674 		mmu_write(pfdev, MMU_INT_CLEAR, mask);
675 
676 		/* Page fault only */
677 		ret = -1;
678 		if ((status & mask) == BIT(as) && (exception_type & 0xF8) == 0xC0)
679 			ret = panfrost_mmu_map_fault_addr(pfdev, as, addr);
680 
681 		if (ret) {
682 			/* terminal fault, print info about the fault */
683 			dev_err(pfdev->dev,
684 				"Unhandled Page fault in AS%d at VA 0x%016llX\n"
685 				"Reason: %s\n"
686 				"raw fault status: 0x%X\n"
687 				"decoded fault status: %s\n"
688 				"exception type 0x%X: %s\n"
689 				"access type 0x%X: %s\n"
690 				"source id 0x%X\n",
691 				as, addr,
692 				"TODO",
693 				fault_status,
694 				(fault_status & (1 << 10) ? "DECODER FAULT" : "SLAVE FAULT"),
695 				exception_type, panfrost_exception_name(exception_type),
696 				access_type, access_type_name(pfdev, fault_status),
697 				source_id);
698 
699 			spin_lock(&pfdev->as_lock);
700 			/* Ignore MMU interrupts on this AS until it's been
701 			 * re-enabled.
702 			 */
703 			pfdev->as_faulty_mask |= mask;
704 
705 			/* Disable the MMU to kill jobs on this AS. */
706 			panfrost_mmu_disable(pfdev, as);
707 			spin_unlock(&pfdev->as_lock);
708 		}
709 
710 		status &= ~mask;
711 
712 		/* If we received new MMU interrupts, process them before returning. */
713 		if (!status)
714 			status = mmu_read(pfdev, MMU_INT_RAWSTAT) & ~pfdev->as_faulty_mask;
715 	}
716 
717 	spin_lock(&pfdev->as_lock);
718 	mmu_write(pfdev, MMU_INT_MASK, ~pfdev->as_faulty_mask);
719 	spin_unlock(&pfdev->as_lock);
720 
721 	return IRQ_HANDLED;
722 };
723 
724 int panfrost_mmu_init(struct panfrost_device *pfdev)
725 {
726 	int err, irq;
727 
728 	irq = platform_get_irq_byname(to_platform_device(pfdev->dev), "mmu");
729 	if (irq <= 0)
730 		return -ENODEV;
731 
732 	err = devm_request_threaded_irq(pfdev->dev, irq,
733 					panfrost_mmu_irq_handler,
734 					panfrost_mmu_irq_handler_thread,
735 					IRQF_SHARED, KBUILD_MODNAME "-mmu",
736 					pfdev);
737 
738 	if (err) {
739 		dev_err(pfdev->dev, "failed to request mmu irq");
740 		return err;
741 	}
742 
743 	return 0;
744 }
745 
746 void panfrost_mmu_fini(struct panfrost_device *pfdev)
747 {
748 	mmu_write(pfdev, MMU_INT_MASK, 0);
749 }
750