1// SPDX-License-Identifier: MIT
2
3#include <linux/fb.h>
4
5#include <drm/drm_crtc_helper.h>
6#include <drm/drm_drv.h>
7#include <drm/drm_fb_helper.h>
8#include <drm/drm_framebuffer.h>
9#include <drm/drm_gem_dma_helper.h>
10
11#include <drm/drm_fbdev_dma.h>
12
13/*
14 * struct fb_ops
15 */
16
17static int drm_fbdev_dma_fb_open(struct fb_info *info, int user)
18{
19	struct drm_fb_helper *fb_helper = info->par;
20
21	/* No need to take a ref for fbcon because it unbinds on unregister */
22	if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
23		return -ENODEV;
24
25	return 0;
26}
27
28static int drm_fbdev_dma_fb_release(struct fb_info *info, int user)
29{
30	struct drm_fb_helper *fb_helper = info->par;
31
32	if (user)
33		module_put(fb_helper->dev->driver->fops->owner);
34
35	return 0;
36}
37
38static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
39{
40	struct drm_fb_helper *fb_helper = info->par;
41
42	if (!fb_helper->dev)
43		return;
44
45	drm_fb_helper_fini(fb_helper);
46
47	drm_client_buffer_vunmap(fb_helper->buffer);
48	drm_client_framebuffer_delete(fb_helper->buffer);
49	drm_client_release(&fb_helper->client);
50	drm_fb_helper_unprepare(fb_helper);
51	kfree(fb_helper);
52}
53
54static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
55{
56	struct drm_fb_helper *fb_helper = info->par;
57
58	return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
59}
60
61static const struct fb_ops drm_fbdev_dma_fb_ops = {
62	.owner = THIS_MODULE,
63	.fb_open = drm_fbdev_dma_fb_open,
64	.fb_release = drm_fbdev_dma_fb_release,
65	__FB_DEFAULT_DMAMEM_OPS_RDWR,
66	DRM_FB_HELPER_DEFAULT_OPS,
67	__FB_DEFAULT_DMAMEM_OPS_DRAW,
68	.fb_mmap = drm_fbdev_dma_fb_mmap,
69	.fb_destroy = drm_fbdev_dma_fb_destroy,
70};
71
72/*
73 * struct drm_fb_helper
74 */
75
76static int drm_fbdev_dma_helper_fb_probe(struct drm_fb_helper *fb_helper,
77					 struct drm_fb_helper_surface_size *sizes)
78{
79	struct drm_client_dev *client = &fb_helper->client;
80	struct drm_device *dev = fb_helper->dev;
81	struct drm_client_buffer *buffer;
82	struct drm_gem_dma_object *dma_obj;
83	struct drm_framebuffer *fb;
84	struct fb_info *info;
85	u32 format;
86	struct iosys_map map;
87	int ret;
88
89	drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
90		    sizes->surface_width, sizes->surface_height,
91		    sizes->surface_bpp);
92
93	format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
94	buffer = drm_client_framebuffer_create(client, sizes->surface_width,
95					       sizes->surface_height, format);
96	if (IS_ERR(buffer))
97		return PTR_ERR(buffer);
98	dma_obj = to_drm_gem_dma_obj(buffer->gem);
99
100	fb = buffer->fb;
101	if (drm_WARN_ON(dev, fb->funcs->dirty)) {
102		ret = -ENODEV; /* damage handling not supported; use generic emulation */
103		goto err_drm_client_buffer_delete;
104	}
105
106	ret = drm_client_buffer_vmap(buffer, &map);
107	if (ret) {
108		goto err_drm_client_buffer_delete;
109	} else if (drm_WARN_ON(dev, map.is_iomem)) {
110		ret = -ENODEV; /* I/O memory not supported; use generic emulation */
111		goto err_drm_client_buffer_delete;
112	}
113
114	fb_helper->buffer = buffer;
115	fb_helper->fb = buffer->fb;
116
117	info = drm_fb_helper_alloc_info(fb_helper);
118	if (IS_ERR(info)) {
119		ret = PTR_ERR(info);
120		goto err_drm_client_buffer_vunmap;
121	}
122
123	drm_fb_helper_fill_info(info, fb_helper, sizes);
124
125	info->fbops = &drm_fbdev_dma_fb_ops;
126
127	/* screen */
128	info->flags |= FBINFO_VIRTFB; /* system memory */
129	if (dma_obj->map_noncoherent)
130		info->flags |= FBINFO_READS_FAST; /* signal caching */
131	info->screen_size = sizes->surface_height * fb->pitches[0];
132	info->screen_buffer = map.vaddr;
133	info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
134	info->fix.smem_len = info->screen_size;
135
136	return 0;
137
138err_drm_client_buffer_vunmap:
139	fb_helper->fb = NULL;
140	fb_helper->buffer = NULL;
141	drm_client_buffer_vunmap(buffer);
142err_drm_client_buffer_delete:
143	drm_client_framebuffer_delete(buffer);
144	return ret;
145}
146
147static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
148	.fb_probe = drm_fbdev_dma_helper_fb_probe,
149};
150
151/*
152 * struct drm_client_funcs
153 */
154
155static void drm_fbdev_dma_client_unregister(struct drm_client_dev *client)
156{
157	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
158
159	if (fb_helper->info) {
160		drm_fb_helper_unregister_info(fb_helper);
161	} else {
162		drm_client_release(&fb_helper->client);
163		drm_fb_helper_unprepare(fb_helper);
164		kfree(fb_helper);
165	}
166}
167
168static int drm_fbdev_dma_client_restore(struct drm_client_dev *client)
169{
170	drm_fb_helper_lastclose(client->dev);
171
172	return 0;
173}
174
175static int drm_fbdev_dma_client_hotplug(struct drm_client_dev *client)
176{
177	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
178	struct drm_device *dev = client->dev;
179	int ret;
180
181	if (dev->fb_helper)
182		return drm_fb_helper_hotplug_event(dev->fb_helper);
183
184	ret = drm_fb_helper_init(dev, fb_helper);
185	if (ret)
186		goto err_drm_err;
187
188	if (!drm_drv_uses_atomic_modeset(dev))
189		drm_helper_disable_unused_functions(dev);
190
191	ret = drm_fb_helper_initial_config(fb_helper);
192	if (ret)
193		goto err_drm_fb_helper_fini;
194
195	return 0;
196
197err_drm_fb_helper_fini:
198	drm_fb_helper_fini(fb_helper);
199err_drm_err:
200	drm_err(dev, "fbdev-dma: Failed to setup generic emulation (ret=%d)\n", ret);
201	return ret;
202}
203
204static const struct drm_client_funcs drm_fbdev_dma_client_funcs = {
205	.owner		= THIS_MODULE,
206	.unregister	= drm_fbdev_dma_client_unregister,
207	.restore	= drm_fbdev_dma_client_restore,
208	.hotplug	= drm_fbdev_dma_client_hotplug,
209};
210
211/**
212 * drm_fbdev_dma_setup() - Setup fbdev emulation for GEM DMA helpers
213 * @dev: DRM device
214 * @preferred_bpp: Preferred bits per pixel for the device.
215 *                 32 is used if this is zero.
216 *
217 * This function sets up fbdev emulation for GEM DMA drivers that support
218 * dumb buffers with a virtual address and that can be mmap'ed.
219 * drm_fbdev_dma_setup() shall be called after the DRM driver registered
220 * the new DRM device with drm_dev_register().
221 *
222 * Restore, hotplug events and teardown are all taken care of. Drivers that do
223 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
224 * Simple drivers might use drm_mode_config_helper_suspend().
225 *
226 * This function is safe to call even when there are no connectors present.
227 * Setup will be retried on the next hotplug event.
228 *
229 * The fbdev is destroyed by drm_dev_unregister().
230 */
231void drm_fbdev_dma_setup(struct drm_device *dev, unsigned int preferred_bpp)
232{
233	struct drm_fb_helper *fb_helper;
234	int ret;
235
236	drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
237	drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
238
239	fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
240	if (!fb_helper)
241		return;
242	drm_fb_helper_prepare(dev, fb_helper, preferred_bpp, &drm_fbdev_dma_helper_funcs);
243
244	ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_dma_client_funcs);
245	if (ret) {
246		drm_err(dev, "Failed to register client: %d\n", ret);
247		goto err_drm_client_init;
248	}
249
250	drm_client_register(&fb_helper->client);
251
252	return;
253
254err_drm_client_init:
255	drm_fb_helper_unprepare(fb_helper);
256	kfree(fb_helper);
257}
258EXPORT_SYMBOL(drm_fbdev_dma_setup);
259