mtk_gem.c

  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, dma_obj->sgt);
 30	else
 31		dma_free_wc(priv->dma_dev, dma_obj->base.size,
 32			    dma_obj->vaddr, dma_obj->dma_addr);
 33
 34	/* release file pointer to gem object. */
 35	drm_gem_object_release(obj);
 36
 37	kfree(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(-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(sgt);
 62		return ERR_PTR(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(-EINVAL);
 87
 88	dma_obj = kzalloc(sizeof(*dma_obj), GFP_KERNEL);
 89	if (!dma_obj)
 90		return ERR_PTR(-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, &dma_obj->base, size);
 97	} else {
 98		ret = drm_gem_object_init(dev, &dma_obj->base, size);
 99	}
100	if (ret) {
101		DRM_ERROR("failed to initialize gem object\n");
102		kfree(dma_obj);
103		return ERR_PTR(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, false);
117	if (IS_ERR(dma_obj))
118		return ERR_CAST(dma_obj);
119
120	obj = &dma_obj->base;
121
122	dma_obj->vaddr = dma_alloc_wc(priv->dma_dev, obj->size,
123				      &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(dma_obj);
140	return ERR_PTR(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, args->size);
160	if (IS_ERR(dma_obj))
161		return PTR_ERR(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, &dma_obj->base, &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(&dma_obj->base);
173
174	return 0;
175
176err_handle_create:
177	mtk_gem_free_object(&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(&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(vm_get_page_prot(vma->vm_flags));
202	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
203
204	ret = dma_mmap_wc(priv->dma_dev, vma, dma_obj->vaddr,
205			  dma_obj->dma_addr, 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(-EINVAL);
221	}
222
223	dma_obj = mtk_gem_init(dev, attach->dmabuf->size, true);
224	if (IS_ERR(dma_obj))
225		return ERR_CAST(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}