1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2015 MediaTek Inc.
4 * Copyright (c) 2025 Collabora Ltd.
5 * AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
6 */
7
8#include <linux/dma-buf.h>
9#include <linux/vmalloc.h>
10
11#include <drm/drm.h>
12#include <drm/drm_device.h>
13#include <drm/drm_gem.h>
14#include <drm/drm_gem_dma_helper.h>
15#include <drm/drm_prime.h>
16#include <drm/drm_print.h>
17
18#include "mtk_drm_drv.h"
19#include "mtk_gem.h"
20
21static int mtk_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma);
22
23static void mtk_gem_free_object(struct drm_gem_object *obj)
24{
25 struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(obj);
26 struct mtk_drm_private *priv = obj->dev->dev_private;
27
28 if (dma_obj->sgt)
29 drm_prime_gem_destroy(obj, sg: dma_obj->sgt);
30 else
31 dma_free_wc(dev: priv->dma_dev, size: dma_obj->base.size,
32 cpu_addr: dma_obj->vaddr, dma_addr: dma_obj->dma_addr);
33
34 /* release file pointer to gem object. */
35 drm_gem_object_release(obj);
36
37 kfree(objp: dma_obj);
38}
39
40/*
41 * Allocate a sg_table for this GEM object.
42 * Note: Both the table's contents, and the sg_table itself must be freed by
43 * the caller.
44 * Returns a pointer to the newly allocated sg_table, or an ERR_PTR() error.
45 */
46static struct sg_table *mtk_gem_prime_get_sg_table(struct drm_gem_object *obj)
47{
48 struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(obj);
49 struct mtk_drm_private *priv = obj->dev->dev_private;
50 struct sg_table *sgt;
51 int ret;
52
53 sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
54 if (!sgt)
55 return ERR_PTR(error: -ENOMEM);
56
57 ret = dma_get_sgtable(priv->dma_dev, sgt, dma_obj->vaddr,
58 dma_obj->dma_addr, obj->size);
59 if (ret) {
60 DRM_ERROR("failed to allocate sgt, %d\n", ret);
61 kfree(objp: sgt);
62 return ERR_PTR(error: ret);
63 }
64
65 return sgt;
66}
67
68static const struct drm_gem_object_funcs mtk_gem_object_funcs = {
69 .free = mtk_gem_free_object,
70 .print_info = drm_gem_dma_object_print_info,
71 .get_sg_table = mtk_gem_prime_get_sg_table,
72 .vmap = drm_gem_dma_object_vmap,
73 .mmap = mtk_gem_object_mmap,
74 .vm_ops = &drm_gem_dma_vm_ops,
75};
76
77static struct drm_gem_dma_object *mtk_gem_init(struct drm_device *dev,
78 unsigned long size, bool private)
79{
80 struct drm_gem_dma_object *dma_obj;
81 int ret;
82
83 size = round_up(size, PAGE_SIZE);
84
85 if (size == 0)
86 return ERR_PTR(error: -EINVAL);
87
88 dma_obj = kzalloc(sizeof(*dma_obj), GFP_KERNEL);
89 if (!dma_obj)
90 return ERR_PTR(error: -ENOMEM);
91
92 dma_obj->base.funcs = &mtk_gem_object_funcs;
93
94 if (private) {
95 ret = 0;
96 drm_gem_private_object_init(dev, obj: &dma_obj->base, size);
97 } else {
98 ret = drm_gem_object_init(dev, obj: &dma_obj->base, size);
99 }
100 if (ret) {
101 DRM_ERROR("failed to initialize gem object\n");
102 kfree(objp: dma_obj);
103 return ERR_PTR(error: ret);
104 }
105
106 return dma_obj;
107}
108
109static struct drm_gem_dma_object *mtk_gem_create(struct drm_device *dev, size_t size)
110{
111 struct mtk_drm_private *priv = dev->dev_private;
112 struct drm_gem_dma_object *dma_obj;
113 struct drm_gem_object *obj;
114 int ret;
115
116 dma_obj = mtk_gem_init(dev, size, private: false);
117 if (IS_ERR(ptr: dma_obj))
118 return ERR_CAST(ptr: dma_obj);
119
120 obj = &dma_obj->base;
121
122 dma_obj->vaddr = dma_alloc_wc(dev: priv->dma_dev, size: obj->size,
123 dma_addr: &dma_obj->dma_addr,
124 GFP_KERNEL | __GFP_NOWARN);
125 if (!dma_obj->vaddr) {
126 DRM_ERROR("failed to allocate %zx byte dma buffer", obj->size);
127 ret = -ENOMEM;
128 goto err_gem_free;
129 }
130
131 DRM_DEBUG_DRIVER("vaddr = %p dma_addr = %pad size = %zu\n",
132 dma_obj->vaddr, &dma_obj->dma_addr,
133 size);
134
135 return dma_obj;
136
137err_gem_free:
138 drm_gem_object_release(obj);
139 kfree(objp: dma_obj);
140 return ERR_PTR(error: ret);
141}
142
143int mtk_gem_dumb_create(struct drm_file *file_priv, struct drm_device *dev,
144 struct drm_mode_create_dumb *args)
145{
146 struct drm_gem_dma_object *dma_obj;
147 int ret;
148
149 args->pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
150
151 /*
152 * Multiply 2 variables of different types,
153 * for example: args->size = args->spacing * args->height;
154 * may cause coverity issue with unintentional overflow.
155 */
156 args->size = args->pitch;
157 args->size *= args->height;
158
159 dma_obj = mtk_gem_create(dev, size: args->size);
160 if (IS_ERR(ptr: dma_obj))
161 return PTR_ERR(ptr: dma_obj);
162
163 /*
164 * allocate a id of idr table where the obj is registered
165 * and handle has the id what user can see.
166 */
167 ret = drm_gem_handle_create(file_priv, obj: &dma_obj->base, handlep: &args->handle);
168 if (ret)
169 goto err_handle_create;
170
171 /* drop reference from allocate - handle holds it now. */
172 drm_gem_object_put(obj: &dma_obj->base);
173
174 return 0;
175
176err_handle_create:
177 mtk_gem_free_object(obj: &dma_obj->base);
178 return ret;
179}
180
181static int mtk_gem_object_mmap(struct drm_gem_object *obj,
182 struct vm_area_struct *vma)
183
184{
185 struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(obj);
186 struct mtk_drm_private *priv = obj->dev->dev_private;
187 int ret;
188
189 /*
190 * Set vm_pgoff (used as a fake buffer offset by DRM) to 0 and map the
191 * whole buffer from the start.
192 */
193 vma->vm_pgoff -= drm_vma_node_start(node: &obj->vma_node);
194
195 /*
196 * dma_alloc_attrs() allocated a struct page table for mtk_gem, so clear
197 * VM_PFNMAP flag that was set by drm_gem_mmap_obj()/drm_gem_mmap().
198 */
199 vm_flags_mod(vma, VM_IO | VM_DONTEXPAND | VM_DONTDUMP, VM_PFNMAP);
200
201 vma->vm_page_prot = pgprot_writecombine(prot: vm_get_page_prot(vm_flags: vma->vm_flags));
202 vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
203
204 ret = dma_mmap_wc(dev: priv->dma_dev, vma, cpu_addr: dma_obj->vaddr,
205 dma_addr: dma_obj->dma_addr, size: obj->size);
206 if (ret)
207 drm_gem_vm_close(vma);
208
209 return ret;
210}
211
212struct drm_gem_object *mtk_gem_prime_import_sg_table(struct drm_device *dev,
213 struct dma_buf_attachment *attach, struct sg_table *sgt)
214{
215 struct drm_gem_dma_object *dma_obj;
216
217 /* check if the entries in the sg_table are contiguous */
218 if (drm_prime_get_contiguous_size(sgt) < attach->dmabuf->size) {
219 DRM_ERROR("sg_table is not contiguous");
220 return ERR_PTR(error: -EINVAL);
221 }
222
223 dma_obj = mtk_gem_init(dev, size: attach->dmabuf->size, private: true);
224 if (IS_ERR(ptr: dma_obj))
225 return ERR_CAST(ptr: dma_obj);
226
227 dma_obj->dma_addr = sg_dma_address(sgt->sgl);
228 dma_obj->sgt = sgt;
229
230 return &dma_obj->base;
231}
232

source code of linux/drivers/gpu/drm/mediatek/mtk_gem.c