1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * psb GEM interface
4 *
5 * Copyright (c) 2011, Intel Corporation.
6 *
7 * Authors: Alan Cox
8 *
9 * TODO:
10 * - we need to work out if the MMU is relevant (eg for
11 * accelerated operations on a GEM object)
12 */
13
14 #include <linux/pagemap.h>
15
16 #include <drm/drm.h>
17 #include <drm/drm_vma_manager.h>
18
19 #include "gem.h"
20 #include "psb_drv.h"
21
22 static vm_fault_t psb_gem_fault(struct vm_fault *vmf);
23
psb_gem_free_object(struct drm_gem_object * obj)24 static void psb_gem_free_object(struct drm_gem_object *obj)
25 {
26 struct gtt_range *gtt = container_of(obj, struct gtt_range, gem);
27
28 /* Remove the list map if one is present */
29 drm_gem_free_mmap_offset(obj);
30 drm_gem_object_release(obj);
31
32 /* This must occur last as it frees up the memory of the GEM object */
33 psb_gtt_free_range(obj->dev, gtt);
34 }
35
36 static const struct vm_operations_struct psb_gem_vm_ops = {
37 .fault = psb_gem_fault,
38 .open = drm_gem_vm_open,
39 .close = drm_gem_vm_close,
40 };
41
42 const struct drm_gem_object_funcs psb_gem_object_funcs = {
43 .free = psb_gem_free_object,
44 .vm_ops = &psb_gem_vm_ops,
45 };
46
47 /**
48 * psb_gem_create - create a mappable object
49 * @file: the DRM file of the client
50 * @dev: our device
51 * @size: the size requested
52 * @handlep: returned handle (opaque number)
53 * @stolen: unused
54 * @align: unused
55 *
56 * Create a GEM object, fill in the boilerplate and attach a handle to
57 * it so that userspace can speak about it. This does the core work
58 * for the various methods that do/will create GEM objects for things
59 */
psb_gem_create(struct drm_file * file,struct drm_device * dev,u64 size,u32 * handlep,int stolen,u32 align)60 int psb_gem_create(struct drm_file *file, struct drm_device *dev, u64 size,
61 u32 *handlep, int stolen, u32 align)
62 {
63 struct gtt_range *r;
64 int ret;
65 u32 handle;
66
67 size = roundup(size, PAGE_SIZE);
68
69 /* Allocate our object - for now a direct gtt range which is not
70 stolen memory backed */
71 r = psb_gtt_alloc_range(dev, size, "gem", 0, PAGE_SIZE);
72 if (r == NULL) {
73 dev_err(dev->dev, "no memory for %lld byte GEM object\n", size);
74 return -ENOSPC;
75 }
76 r->gem.funcs = &psb_gem_object_funcs;
77 /* Initialize the extra goodies GEM needs to do all the hard work */
78 if (drm_gem_object_init(dev, &r->gem, size) != 0) {
79 psb_gtt_free_range(dev, r);
80 /* GEM doesn't give an error code so use -ENOMEM */
81 dev_err(dev->dev, "GEM init failed for %lld\n", size);
82 return -ENOMEM;
83 }
84 /* Limit the object to 32bit mappings */
85 mapping_set_gfp_mask(r->gem.filp->f_mapping, GFP_KERNEL | __GFP_DMA32);
86 /* Give the object a handle so we can carry it more easily */
87 ret = drm_gem_handle_create(file, &r->gem, &handle);
88 if (ret) {
89 dev_err(dev->dev, "GEM handle failed for %p, %lld\n",
90 &r->gem, size);
91 drm_gem_object_release(&r->gem);
92 psb_gtt_free_range(dev, r);
93 return ret;
94 }
95 /* We have the initial and handle reference but need only one now */
96 drm_gem_object_put(&r->gem);
97 *handlep = handle;
98 return 0;
99 }
100
101 /**
102 * psb_gem_dumb_create - create a dumb buffer
103 * @file: our client file
104 * @dev: our device
105 * @args: the requested arguments copied from userspace
106 *
107 * Allocate a buffer suitable for use for a frame buffer of the
108 * form described by user space. Give userspace a handle by which
109 * to reference it.
110 */
psb_gem_dumb_create(struct drm_file * file,struct drm_device * dev,struct drm_mode_create_dumb * args)111 int psb_gem_dumb_create(struct drm_file *file, struct drm_device *dev,
112 struct drm_mode_create_dumb *args)
113 {
114 args->pitch = ALIGN(args->width * ((args->bpp + 7) / 8), 64);
115 args->size = args->pitch * args->height;
116 return psb_gem_create(file, dev, args->size, &args->handle, 0,
117 PAGE_SIZE);
118 }
119
120 /**
121 * psb_gem_fault - pagefault handler for GEM objects
122 * @vmf: fault detail
123 *
124 * Invoked when a fault occurs on an mmap of a GEM managed area. GEM
125 * does most of the work for us including the actual map/unmap calls
126 * but we need to do the actual page work.
127 *
128 * This code eventually needs to handle faulting objects in and out
129 * of the GTT and repacking it when we run out of space. We can put
130 * that off for now and for our simple uses
131 *
132 * The VMA was set up by GEM. In doing so it also ensured that the
133 * vma->vm_private_data points to the GEM object that is backing this
134 * mapping.
135 */
psb_gem_fault(struct vm_fault * vmf)136 static vm_fault_t psb_gem_fault(struct vm_fault *vmf)
137 {
138 struct vm_area_struct *vma = vmf->vma;
139 struct drm_gem_object *obj;
140 struct gtt_range *r;
141 int err;
142 vm_fault_t ret;
143 unsigned long pfn;
144 pgoff_t page_offset;
145 struct drm_device *dev;
146 struct drm_psb_private *dev_priv;
147
148 obj = vma->vm_private_data; /* GEM object */
149 dev = obj->dev;
150 dev_priv = dev->dev_private;
151
152 r = container_of(obj, struct gtt_range, gem); /* Get the gtt range */
153
154 /* Make sure we don't parallel update on a fault, nor move or remove
155 something from beneath our feet */
156 mutex_lock(&dev_priv->mmap_mutex);
157
158 /* For now the mmap pins the object and it stays pinned. As things
159 stand that will do us no harm */
160 if (r->mmapping == 0) {
161 err = psb_gtt_pin(r);
162 if (err < 0) {
163 dev_err(dev->dev, "gma500: pin failed: %d\n", err);
164 ret = vmf_error(err);
165 goto fail;
166 }
167 r->mmapping = 1;
168 }
169
170 /* Page relative to the VMA start - we must calculate this ourselves
171 because vmf->pgoff is the fake GEM offset */
172 page_offset = (vmf->address - vma->vm_start) >> PAGE_SHIFT;
173
174 /* CPU view of the page, don't go via the GART for CPU writes */
175 if (r->stolen)
176 pfn = (dev_priv->stolen_base + r->offset) >> PAGE_SHIFT;
177 else
178 pfn = page_to_pfn(r->pages[page_offset]);
179 ret = vmf_insert_pfn(vma, vmf->address, pfn);
180 fail:
181 mutex_unlock(&dev_priv->mmap_mutex);
182
183 return ret;
184 }
185