drm_fbdev_dma.c

  1// SPDX-License-Identifier: MIT
  2
  3#include <linux/export.h>
  4#include <linux/fb.h>
  5#include <linux/vmalloc.h>
  6
  7#include <drm/drm_drv.h>
  8#include <drm/drm_fbdev_dma.h>
  9#include <drm/drm_fb_dma_helper.h>
 10#include <drm/drm_fb_helper.h>
 11#include <drm/drm_framebuffer.h>
 12#include <drm/drm_gem_dma_helper.h>
 13#include <drm/drm_print.h>
 14
 15/*
 16 * struct fb_ops
 17 */
 18
 19static int drm_fbdev_dma_fb_open(struct fb_info *info, int user)
 20{
 21	struct drm_fb_helper *fb_helper = info->par;
 22
 23	/* No need to take a ref for fbcon because it unbinds on unregister */
 24	if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
 25		return -ENODEV;
 26
 27	return 0;
 28}
 29
 30static int drm_fbdev_dma_fb_release(struct fb_info *info, int user)
 31{
 32	struct drm_fb_helper *fb_helper = info->par;
 33
 34	if (user)
 35		module_put(fb_helper->dev->driver->fops->owner);
 36
 37	return 0;
 38}
 39
 40static int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 41{
 42	struct drm_fb_helper *fb_helper = info->par;
 43
 44	return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
 45}
 46
 47static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
 48{
 49	struct drm_fb_helper *fb_helper = info->par;
 50
 51	if (!fb_helper->dev)
 52		return;
 53
 54	if (info->fbdefio)
 55		fb_deferred_io_cleanup(info);
 56	drm_fb_helper_fini(fb_helper);
 57
 58	drm_client_buffer_vunmap(fb_helper->buffer);
 59	drm_client_buffer_delete(fb_helper->buffer);
 60	drm_client_release(&fb_helper->client);
 61}
 62
 63static const struct fb_ops drm_fbdev_dma_fb_ops = {
 64	.owner = THIS_MODULE,
 65	.fb_open = drm_fbdev_dma_fb_open,
 66	.fb_release = drm_fbdev_dma_fb_release,
 67	__FB_DEFAULT_DMAMEM_OPS_RDWR,
 68	DRM_FB_HELPER_DEFAULT_OPS,
 69	__FB_DEFAULT_DMAMEM_OPS_DRAW,
 70	.fb_mmap = drm_fbdev_dma_fb_mmap,
 71	.fb_destroy = drm_fbdev_dma_fb_destroy,
 72};
 73
 74FB_GEN_DEFAULT_DEFERRED_DMAMEM_OPS(drm_fbdev_dma_shadowed,
 75				   drm_fb_helper_damage_range,
 76				   drm_fb_helper_damage_area);
 77
 78static void drm_fbdev_dma_shadowed_fb_destroy(struct fb_info *info)
 79{
 80	struct drm_fb_helper *fb_helper = info->par;
 81	void *shadow = info->screen_buffer;
 82
 83	if (!fb_helper->dev)
 84		return;
 85
 86	if (info->fbdefio)
 87		fb_deferred_io_cleanup(info);
 88	drm_fb_helper_fini(fb_helper);
 89	vfree(shadow);
 90
 91	drm_client_buffer_vunmap(fb_helper->buffer);
 92	drm_client_buffer_delete(fb_helper->buffer);
 93	drm_client_release(&fb_helper->client);
 94}
 95
 96static const struct fb_ops drm_fbdev_dma_shadowed_fb_ops = {
 97	.owner = THIS_MODULE,
 98	.fb_open = drm_fbdev_dma_fb_open,
 99	.fb_release = drm_fbdev_dma_fb_release,
100	FB_DEFAULT_DEFERRED_OPS(drm_fbdev_dma_shadowed),
101	DRM_FB_HELPER_DEFAULT_OPS,
102	.fb_destroy = drm_fbdev_dma_shadowed_fb_destroy,
103};
104
105/*
106 * struct drm_fb_helper
107 */
108
109static void drm_fbdev_dma_damage_blit_real(struct drm_fb_helper *fb_helper,
110					   struct drm_clip_rect *clip,
111					   struct iosys_map *dst)
112{
113	struct drm_framebuffer *fb = fb_helper->fb;
114	size_t offset = clip->y1 * fb->pitches[0];
115	size_t len = clip->x2 - clip->x1;
116	unsigned int y;
117	void *src;
118
119	switch (drm_format_info_bpp(fb->format, 0)) {
120	case 1:
121		offset += clip->x1 / 8;
122		len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
123		break;
124	case 2:
125		offset += clip->x1 / 4;
126		len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
127		break;
128	case 4:
129		offset += clip->x1 / 2;
130		len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
131		break;
132	default:
133		offset += clip->x1 * fb->format->cpp[0];
134		len *= fb->format->cpp[0];
135		break;
136	}
137
138	src = fb_helper->info->screen_buffer + offset;
139	iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
140
141	for (y = clip->y1; y < clip->y2; y++) {
142		iosys_map_memcpy_to(dst, 0, src, len);
143		iosys_map_incr(dst, fb->pitches[0]);
144		src += fb->pitches[0];
145	}
146}
147
148static int drm_fbdev_dma_damage_blit(struct drm_fb_helper *fb_helper,
149				     struct drm_clip_rect *clip)
150{
151	struct drm_client_buffer *buffer = fb_helper->buffer;
152	struct iosys_map dst;
153
154	/*
155	 * For fbdev emulation, we only have to protect against fbdev modeset
156	 * operations. Nothing else will involve the client buffer's BO. So it
157	 * is sufficient to acquire struct drm_fb_helper.lock here.
158	 */
159	mutex_lock(&fb_helper->lock);
160
161	dst = buffer->map;
162	drm_fbdev_dma_damage_blit_real(fb_helper, clip, &dst);
163
164	mutex_unlock(&fb_helper->lock);
165
166	return 0;
167}
168static int drm_fbdev_dma_helper_fb_dirty(struct drm_fb_helper *helper,
169					 struct drm_clip_rect *clip)
170{
171	struct drm_device *dev = helper->dev;
172	int ret;
173
174	/* Call damage handlers only if necessary */
175	if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
176		return 0;
177
178	if (helper->fb->funcs->dirty) {
179		ret = drm_fbdev_dma_damage_blit(helper, clip);
180		if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
181			return ret;
182
183		ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
184		if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
185			return ret;
186	}
187
188	return 0;
189}
190
191static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
192	.fb_dirty = drm_fbdev_dma_helper_fb_dirty,
193};
194
195/*
196 * struct drm_fb_helper
197 */
198
199static int drm_fbdev_dma_driver_fbdev_probe_tail(struct drm_fb_helper *fb_helper,
200						 struct drm_fb_helper_surface_size *sizes)
201{
202	struct drm_device *dev = fb_helper->dev;
203	struct drm_client_buffer *buffer = fb_helper->buffer;
204	struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(buffer->gem);
205	struct drm_framebuffer *fb = fb_helper->fb;
206	struct fb_info *info = fb_helper->info;
207	struct iosys_map map = buffer->map;
208
209	info->fbops = &drm_fbdev_dma_fb_ops;
210
211	/* screen */
212	info->flags |= FBINFO_VIRTFB; /* system memory */
213	if (dma_obj->map_noncoherent)
214		info->flags |= FBINFO_READS_FAST; /* signal caching */
215	info->screen_size = sizes->surface_height * fb->pitches[0];
216	info->screen_buffer = map.vaddr;
217	if (!(info->flags & FBINFO_HIDE_SMEM_START)) {
218		if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer)))
219			info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
220	}
221	info->fix.smem_len = info->screen_size;
222
223	return 0;
224}
225
226static int drm_fbdev_dma_driver_fbdev_probe_tail_shadowed(struct drm_fb_helper *fb_helper,
227							  struct drm_fb_helper_surface_size *sizes)
228{
229	struct drm_client_buffer *buffer = fb_helper->buffer;
230	struct fb_info *info = fb_helper->info;
231	size_t screen_size = buffer->gem->size;
232	void *screen_buffer;
233	int ret;
234
235	/*
236	 * Deferred I/O requires struct page for framebuffer memory,
237	 * which is not guaranteed for all DMA ranges. We thus create
238	 * a shadow buffer in system memory.
239	 */
240	screen_buffer = vzalloc(screen_size);
241	if (!screen_buffer)
242		return -ENOMEM;
243
244	info->fbops = &drm_fbdev_dma_shadowed_fb_ops;
245
246	/* screen */
247	info->flags |= FBINFO_VIRTFB; /* system memory */
248	info->flags |= FBINFO_READS_FAST; /* signal caching */
249	info->screen_buffer = screen_buffer;
250	info->fix.smem_len = screen_size;
251
252	fb_helper->fbdefio.delay = HZ / 20;
253	fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
254
255	info->fbdefio = &fb_helper->fbdefio;
256	ret = fb_deferred_io_init(info);
257	if (ret)
258		goto err_vfree;
259
260	return 0;
261
262err_vfree:
263	vfree(screen_buffer);
264	return ret;
265}
266
267int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
268				     struct drm_fb_helper_surface_size *sizes)
269{
270	struct drm_client_dev *client = &fb_helper->client;
271	struct drm_device *dev = fb_helper->dev;
272	struct fb_info *info = fb_helper->info;
273	struct drm_client_buffer *buffer;
274	struct drm_framebuffer *fb;
275	u32 format;
276	struct iosys_map map;
277	int ret;
278
279	drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
280		    sizes->surface_width, sizes->surface_height,
281		    sizes->surface_bpp);
282
283	format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp,
284					     sizes->surface_depth);
285	buffer = drm_client_buffer_create_dumb(client, sizes->surface_width,
286					       sizes->surface_height, format);
287	if (IS_ERR(buffer))
288		return PTR_ERR(buffer);
289
290	fb = buffer->fb;
291
292	ret = drm_client_buffer_vmap(buffer, &map);
293	if (ret) {
294		goto err_drm_client_buffer_delete;
295	} else if (drm_WARN_ON(dev, map.is_iomem)) {
296		ret = -ENODEV; /* I/O memory not supported; use generic emulation */
297		goto err_drm_client_buffer_delete;
298	}
299
300	fb_helper->funcs = &drm_fbdev_dma_helper_funcs;
301	fb_helper->buffer = buffer;
302	fb_helper->fb = fb;
303
304	drm_fb_helper_fill_info(info, fb_helper, sizes);
305
306	if (fb->funcs->dirty)
307		ret = drm_fbdev_dma_driver_fbdev_probe_tail_shadowed(fb_helper, sizes);
308	else
309		ret = drm_fbdev_dma_driver_fbdev_probe_tail(fb_helper, sizes);
310	if (ret)
311		goto err_drm_client_buffer_vunmap;
312
313	return 0;
314
315err_drm_client_buffer_vunmap:
316	fb_helper->fb = NULL;
317	fb_helper->buffer = NULL;
318	drm_client_buffer_vunmap(buffer);
319err_drm_client_buffer_delete:
320	drm_client_buffer_delete(buffer);
321	return ret;
322}
323EXPORT_SYMBOL(drm_fbdev_dma_driver_fbdev_probe);