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      1 /*	$NetBSD: huge_gem_object.c,v 1.2 2021/12/18 23:45:30 riastradh Exp $	*/
      2 
      3 /*
      4  * SPDX-License-Identifier: MIT
      5  *
      6  * Copyright  2016 Intel Corporation
      7  */
      8 
      9 #include <sys/cdefs.h>
     10 __KERNEL_RCSID(0, "$NetBSD: huge_gem_object.c,v 1.2 2021/12/18 23:45:30 riastradh Exp $");
     11 
     12 #include "i915_scatterlist.h"
     13 
     14 #include "huge_gem_object.h"
     15 
     16 static void huge_free_pages(struct drm_i915_gem_object *obj,
     17 			    struct sg_table *pages)
     18 {
     19 	unsigned long nreal = obj->scratch / PAGE_SIZE;
     20 	struct sgt_iter sgt_iter;
     21 	struct page *page;
     22 
     23 	for_each_sgt_page(page, sgt_iter, pages) {
     24 		__free_page(page);
     25 		if (!--nreal)
     26 			break;
     27 	}
     28 
     29 	sg_free_table(pages);
     30 	kfree(pages);
     31 }
     32 
     33 static int huge_get_pages(struct drm_i915_gem_object *obj)
     34 {
     35 #define GFP (GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY)
     36 	const unsigned long nreal = obj->scratch / PAGE_SIZE;
     37 	const unsigned long npages = obj->base.size / PAGE_SIZE;
     38 	struct scatterlist *sg, *src, *end;
     39 	struct sg_table *pages;
     40 	unsigned long n;
     41 
     42 	pages = kmalloc(sizeof(*pages), GFP);
     43 	if (!pages)
     44 		return -ENOMEM;
     45 
     46 	if (sg_alloc_table(pages, npages, GFP)) {
     47 		kfree(pages);
     48 		return -ENOMEM;
     49 	}
     50 
     51 	sg = pages->sgl;
     52 	for (n = 0; n < nreal; n++) {
     53 		struct page *page;
     54 
     55 		page = alloc_page(GFP | __GFP_HIGHMEM);
     56 		if (!page) {
     57 			sg_mark_end(sg);
     58 			goto err;
     59 		}
     60 
     61 		sg_set_page(sg, page, PAGE_SIZE, 0);
     62 		sg = __sg_next(sg);
     63 	}
     64 	if (nreal < npages) {
     65 		for (end = sg, src = pages->sgl; sg; sg = __sg_next(sg)) {
     66 			sg_set_page(sg, sg_page(src), PAGE_SIZE, 0);
     67 			src = __sg_next(src);
     68 			if (src == end)
     69 				src = pages->sgl;
     70 		}
     71 	}
     72 
     73 	if (i915_gem_gtt_prepare_pages(obj, pages))
     74 		goto err;
     75 
     76 	__i915_gem_object_set_pages(obj, pages, PAGE_SIZE);
     77 
     78 	return 0;
     79 
     80 err:
     81 	huge_free_pages(obj, pages);
     82 	return -ENOMEM;
     83 #undef GFP
     84 }
     85 
     86 static void huge_put_pages(struct drm_i915_gem_object *obj,
     87 			   struct sg_table *pages)
     88 {
     89 	i915_gem_gtt_finish_pages(obj, pages);
     90 	huge_free_pages(obj, pages);
     91 
     92 	obj->mm.dirty = false;
     93 }
     94 
     95 static const struct drm_i915_gem_object_ops huge_ops = {
     96 	.flags = I915_GEM_OBJECT_HAS_STRUCT_PAGE |
     97 		 I915_GEM_OBJECT_IS_SHRINKABLE,
     98 	.get_pages = huge_get_pages,
     99 	.put_pages = huge_put_pages,
    100 };
    101 
    102 struct drm_i915_gem_object *
    103 huge_gem_object(struct drm_i915_private *i915,
    104 		phys_addr_t phys_size,
    105 		dma_addr_t dma_size)
    106 {
    107 	static struct lock_class_key lock_class;
    108 	struct drm_i915_gem_object *obj;
    109 	unsigned int cache_level;
    110 
    111 	GEM_BUG_ON(!phys_size || phys_size > dma_size);
    112 	GEM_BUG_ON(!IS_ALIGNED(phys_size, PAGE_SIZE));
    113 	GEM_BUG_ON(!IS_ALIGNED(dma_size, I915_GTT_PAGE_SIZE));
    114 
    115 	if (overflows_type(dma_size, obj->base.size))
    116 		return ERR_PTR(-E2BIG);
    117 
    118 	obj = i915_gem_object_alloc();
    119 	if (!obj)
    120 		return ERR_PTR(-ENOMEM);
    121 
    122 	drm_gem_private_object_init(&i915->drm, &obj->base, dma_size);
    123 	i915_gem_object_init(obj, &huge_ops, &lock_class);
    124 
    125 	obj->read_domains = I915_GEM_DOMAIN_CPU;
    126 	obj->write_domain = I915_GEM_DOMAIN_CPU;
    127 	cache_level = HAS_LLC(i915) ? I915_CACHE_LLC : I915_CACHE_NONE;
    128 	i915_gem_object_set_cache_coherency(obj, cache_level);
    129 	obj->scratch = phys_size;
    130 
    131 	return obj;
    132 }
    133