1// SPDX-License-Identifier: MIT
2
3#include <linux/export.h>
4#include <linux/fb.h>
5
6#include <drm/drm_drv.h>
7#include <drm/drm_fbdev_shmem.h>
8#include <drm/drm_fb_helper.h>
9#include <drm/drm_framebuffer.h>
10#include <drm/drm_gem_framebuffer_helper.h>
11#include <drm/drm_gem_shmem_helper.h>
12#include <drm/drm_print.h>
13
14/*
15 * struct fb_ops
16 */
17
18static int drm_fbdev_shmem_fb_open(struct fb_info *info, int user)
19{
20 struct drm_fb_helper *fb_helper = info->par;
21
22 /* No need to take a ref for fbcon because it unbinds on unregister */
23 if (user && !try_module_get(module: fb_helper->dev->driver->fops->owner))
24 return -ENODEV;
25
26 return 0;
27}
28
29static int drm_fbdev_shmem_fb_release(struct fb_info *info, int user)
30{
31 struct drm_fb_helper *fb_helper = info->par;
32
33 if (user)
34 module_put(module: fb_helper->dev->driver->fops->owner);
35
36 return 0;
37}
38
39FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_shmem,
40 drm_fb_helper_damage_range,
41 drm_fb_helper_damage_area);
42
43static int drm_fbdev_shmem_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
44{
45 struct drm_fb_helper *fb_helper = info->par;
46 struct drm_framebuffer *fb = fb_helper->fb;
47 struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, plane: 0);
48 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
49
50 if (shmem->map_wc)
51 vma->vm_page_prot = pgprot_writecombine(prot: vma->vm_page_prot);
52
53 return fb_deferred_io_mmap(info, vma);
54}
55
56static void drm_fbdev_shmem_fb_destroy(struct fb_info *info)
57{
58 struct drm_fb_helper *fb_helper = info->par;
59
60 if (!fb_helper->dev)
61 return;
62
63 fb_deferred_io_cleanup(info);
64 drm_fb_helper_fini(helper: fb_helper);
65
66 drm_client_buffer_vunmap(buffer: fb_helper->buffer);
67 drm_client_buffer_delete(buffer: fb_helper->buffer);
68 drm_client_release(client: &fb_helper->client);
69}
70
71static const struct fb_ops drm_fbdev_shmem_fb_ops = {
72 .owner = THIS_MODULE,
73 .fb_open = drm_fbdev_shmem_fb_open,
74 .fb_release = drm_fbdev_shmem_fb_release,
75 __FB_DEFAULT_DEFERRED_OPS_RDWR(drm_fbdev_shmem),
76 DRM_FB_HELPER_DEFAULT_OPS,
77 __FB_DEFAULT_DEFERRED_OPS_DRAW(drm_fbdev_shmem),
78 .fb_mmap = drm_fbdev_shmem_fb_mmap,
79 .fb_destroy = drm_fbdev_shmem_fb_destroy,
80};
81
82static struct page *drm_fbdev_shmem_get_page(struct fb_info *info, unsigned long offset)
83{
84 struct drm_fb_helper *fb_helper = info->par;
85 struct drm_framebuffer *fb = fb_helper->fb;
86 struct drm_gem_object *obj = drm_gem_fb_get_obj(fb, plane: 0);
87 struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
88 unsigned int i = offset >> PAGE_SHIFT;
89 struct page *page;
90
91 if (fb_WARN_ON_ONCE(info, offset > obj->size))
92 return NULL;
93
94 page = shmem->pages[i]; // protected by active vmap
95 if (page)
96 get_page(page);
97 fb_WARN_ON_ONCE(info, !page);
98
99 return page;
100}
101
102/*
103 * struct drm_fb_helper
104 */
105
106static int drm_fbdev_shmem_helper_fb_dirty(struct drm_fb_helper *helper,
107 struct drm_clip_rect *clip)
108{
109 struct drm_device *dev = helper->dev;
110 int ret;
111
112 /* Call damage handlers only if necessary */
113 if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
114 return 0;
115
116 if (helper->fb->funcs->dirty) {
117 ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
118 if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
119 return ret;
120 }
121
122 return 0;
123}
124
125static const struct drm_fb_helper_funcs drm_fbdev_shmem_helper_funcs = {
126 .fb_dirty = drm_fbdev_shmem_helper_fb_dirty,
127};
128
129/*
130 * struct drm_driver
131 */
132
133int drm_fbdev_shmem_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
134 struct drm_fb_helper_surface_size *sizes)
135{
136 struct drm_client_dev *client = &fb_helper->client;
137 struct drm_device *dev = fb_helper->dev;
138 struct fb_info *info = fb_helper->info;
139 struct drm_client_buffer *buffer;
140 struct drm_gem_shmem_object *shmem;
141 struct drm_framebuffer *fb;
142 u32 format;
143 struct iosys_map map;
144 int ret;
145
146 drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
147 sizes->surface_width, sizes->surface_height,
148 sizes->surface_bpp);
149
150 format = drm_driver_legacy_fb_format(dev, bpp: sizes->surface_bpp, depth: sizes->surface_depth);
151 buffer = drm_client_buffer_create_dumb(client, width: sizes->surface_width,
152 height: sizes->surface_height, format);
153 if (IS_ERR(ptr: buffer))
154 return PTR_ERR(ptr: buffer);
155 shmem = to_drm_gem_shmem_obj(buffer->gem);
156
157 fb = buffer->fb;
158
159 ret = drm_client_buffer_vmap(buffer, map: &map);
160 if (ret) {
161 goto err_drm_client_buffer_delete;
162 } else if (drm_WARN_ON(dev, map.is_iomem)) {
163 ret = -ENODEV; /* I/O memory not supported; use generic emulation */
164 goto err_drm_client_buffer_delete;
165 }
166
167 fb_helper->funcs = &drm_fbdev_shmem_helper_funcs;
168 fb_helper->buffer = buffer;
169 fb_helper->fb = fb;
170
171 drm_fb_helper_fill_info(info, fb_helper, sizes);
172
173 info->fbops = &drm_fbdev_shmem_fb_ops;
174
175 /* screen */
176 info->flags |= FBINFO_VIRTFB; /* system memory */
177 if (!shmem->map_wc)
178 info->flags |= FBINFO_READS_FAST; /* signal caching */
179 info->screen_size = sizes->surface_height * fb->pitches[0];
180 info->screen_buffer = map.vaddr;
181 info->fix.smem_len = info->screen_size;
182
183 /* deferred I/O */
184 fb_helper->fbdefio.delay = HZ / 20;
185 fb_helper->fbdefio.get_page = drm_fbdev_shmem_get_page;
186 fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
187
188 info->fbdefio = &fb_helper->fbdefio;
189 ret = fb_deferred_io_init(info);
190 if (ret)
191 goto err_drm_client_buffer_vunmap;
192
193 return 0;
194
195err_drm_client_buffer_vunmap:
196 fb_helper->fb = NULL;
197 fb_helper->buffer = NULL;
198 drm_client_buffer_vunmap(buffer);
199err_drm_client_buffer_delete:
200 drm_client_buffer_delete(buffer);
201 return ret;
202}
203EXPORT_SYMBOL(drm_fbdev_shmem_driver_fbdev_probe);
204

source code of linux/drivers/gpu/drm/drm_fbdev_shmem.c