1// SPDX-License-Identifier: MIT
  2
  3#include <linux/fb.h>
  4#include <linux/vmalloc.h>
  5
  6#include <drm/drm_drv.h>
  7#include <drm/drm_fbdev_dma.h>
  8#include <drm/drm_fb_dma_helper.h>
  9#include <drm/drm_fb_helper.h>
 10#include <drm/drm_framebuffer.h>
 11#include <drm/drm_gem_dma_helper.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 int drm_fbdev_dma_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 39{
 40	struct drm_fb_helper *fb_helper = info->par;
 41
 42	return drm_gem_prime_mmap(fb_helper->buffer->gem, vma);
 43}
 44
 45static void drm_fbdev_dma_fb_destroy(struct fb_info *info)
 46{
 47	struct drm_fb_helper *fb_helper = info->par;
 48
 49	if (!fb_helper->dev)
 50		return;
 51
 52	if (info->fbdefio)
 53		fb_deferred_io_cleanup(info);
 54	drm_fb_helper_fini(fb_helper);
 55
 56	drm_client_buffer_vunmap(fb_helper->buffer);
 57	drm_client_framebuffer_delete(fb_helper->buffer);
 58	drm_client_release(&fb_helper->client);
 59	drm_fb_helper_unprepare(fb_helper);
 60	kfree(fb_helper);
 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_framebuffer_delete(fb_helper->buffer);
 93	drm_client_release(&fb_helper->client);
 94	drm_fb_helper_unprepare(fb_helper);
 95	kfree(fb_helper);
 96}
 97
 98static const struct fb_ops drm_fbdev_dma_shadowed_fb_ops = {
 99	.owner = THIS_MODULE,
100	.fb_open = drm_fbdev_dma_fb_open,
101	.fb_release = drm_fbdev_dma_fb_release,
102	FB_DEFAULT_DEFERRED_OPS(drm_fbdev_dma_shadowed),
103	DRM_FB_HELPER_DEFAULT_OPS,
104	.fb_destroy = drm_fbdev_dma_shadowed_fb_destroy,
105};
106
107/*
108 * struct drm_fb_helper
109 */
110
111static void drm_fbdev_dma_damage_blit_real(struct drm_fb_helper *fb_helper,
112					   struct drm_clip_rect *clip,
113					   struct iosys_map *dst)
114{
115	struct drm_framebuffer *fb = fb_helper->fb;
116	size_t offset = clip->y1 * fb->pitches[0];
117	size_t len = clip->x2 - clip->x1;
118	unsigned int y;
119	void *src;
120
121	switch (drm_format_info_bpp(fb->format, 0)) {
122	case 1:
123		offset += clip->x1 / 8;
124		len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
125		break;
126	case 2:
127		offset += clip->x1 / 4;
128		len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
129		break;
130	case 4:
131		offset += clip->x1 / 2;
132		len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
133		break;
134	default:
135		offset += clip->x1 * fb->format->cpp[0];
136		len *= fb->format->cpp[0];
137		break;
138	}
139
140	src = fb_helper->info->screen_buffer + offset;
141	iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
142
143	for (y = clip->y1; y < clip->y2; y++) {
144		iosys_map_memcpy_to(dst, 0, src, len);
145		iosys_map_incr(dst, fb->pitches[0]);
146		src += fb->pitches[0];
147	}
148}
149
150static int drm_fbdev_dma_damage_blit(struct drm_fb_helper *fb_helper,
151				     struct drm_clip_rect *clip)
152{
153	struct drm_client_buffer *buffer = fb_helper->buffer;
154	struct iosys_map dst;
155
156	/*
157	 * For fbdev emulation, we only have to protect against fbdev modeset
158	 * operations. Nothing else will involve the client buffer's BO. So it
159	 * is sufficient to acquire struct drm_fb_helper.lock here.
160	 */
161	mutex_lock(&fb_helper->lock);
162
163	dst = buffer->map;
164	drm_fbdev_dma_damage_blit_real(fb_helper, clip, &dst);
165
166	mutex_unlock(&fb_helper->lock);
167
168	return 0;
169}
170static int drm_fbdev_dma_helper_fb_dirty(struct drm_fb_helper *helper,
171					 struct drm_clip_rect *clip)
172{
173	struct drm_device *dev = helper->dev;
174	int ret;
175
176	/* Call damage handlers only if necessary */
177	if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
178		return 0;
179
180	if (helper->fb->funcs->dirty) {
181		ret = drm_fbdev_dma_damage_blit(helper, clip);
182		if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
183			return ret;
184
185		ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
186		if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
187			return ret;
188	}
189
190	return 0;
191}
192
193static const struct drm_fb_helper_funcs drm_fbdev_dma_helper_funcs = {
194	.fb_dirty = drm_fbdev_dma_helper_fb_dirty,
195};
196
197/*
198 * struct drm_fb_helper
199 */
200
201static int drm_fbdev_dma_driver_fbdev_probe_tail(struct drm_fb_helper *fb_helper,
202						 struct drm_fb_helper_surface_size *sizes)
203{
204	struct drm_device *dev = fb_helper->dev;
205	struct drm_client_buffer *buffer = fb_helper->buffer;
206	struct drm_gem_dma_object *dma_obj = to_drm_gem_dma_obj(buffer->gem);
207	struct drm_framebuffer *fb = fb_helper->fb;
208	struct fb_info *info = fb_helper->info;
209	struct iosys_map map = buffer->map;
210
211	info->fbops = &drm_fbdev_dma_fb_ops;
212
213	/* screen */
214	info->flags |= FBINFO_VIRTFB; /* system memory */
215	if (dma_obj->map_noncoherent)
216		info->flags |= FBINFO_READS_FAST; /* signal caching */
217	info->screen_size = sizes->surface_height * fb->pitches[0];
218	info->screen_buffer = map.vaddr;
219	if (!(info->flags & FBINFO_HIDE_SMEM_START)) {
220		if (!drm_WARN_ON(dev, is_vmalloc_addr(info->screen_buffer)))
221			info->fix.smem_start = page_to_phys(virt_to_page(info->screen_buffer));
222	}
223	info->fix.smem_len = info->screen_size;
224
225	return 0;
226}
227
228static int drm_fbdev_dma_driver_fbdev_probe_tail_shadowed(struct drm_fb_helper *fb_helper,
229							  struct drm_fb_helper_surface_size *sizes)
230{
231	struct drm_client_buffer *buffer = fb_helper->buffer;
232	struct fb_info *info = fb_helper->info;
233	size_t screen_size = buffer->gem->size;
234	void *screen_buffer;
235	int ret;
236
237	/*
238	 * Deferred I/O requires struct page for framebuffer memory,
239	 * which is not guaranteed for all DMA ranges. We thus create
240	 * a shadow buffer in system memory.
241	 */
242	screen_buffer = vzalloc(screen_size);
243	if (!screen_buffer)
244		return -ENOMEM;
245
246	info->fbops = &drm_fbdev_dma_shadowed_fb_ops;
247
248	/* screen */
249	info->flags |= FBINFO_VIRTFB; /* system memory */
250	info->flags |= FBINFO_READS_FAST; /* signal caching */
251	info->screen_buffer = screen_buffer;
252	info->fix.smem_len = screen_size;
253
254	fb_helper->fbdefio.delay = HZ / 20;
255	fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
256
257	info->fbdefio = &fb_helper->fbdefio;
258	ret = fb_deferred_io_init(info);
259	if (ret)
260		goto err_vfree;
261
262	return 0;
263
264err_vfree:
265	vfree(screen_buffer);
266	return ret;
267}
268
269int drm_fbdev_dma_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
270				     struct drm_fb_helper_surface_size *sizes)
271{
272	struct drm_client_dev *client = &fb_helper->client;
273	struct drm_device *dev = fb_helper->dev;
274	struct drm_client_buffer *buffer;
275	struct drm_framebuffer *fb;
276	struct fb_info *info;
277	u32 format;
278	struct iosys_map map;
279	int ret;
280
281	drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
282		    sizes->surface_width, sizes->surface_height,
283		    sizes->surface_bpp);
284
285	format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp,
286					     sizes->surface_depth);
287	buffer = drm_client_framebuffer_create(client, sizes->surface_width,
288					       sizes->surface_height, format);
289	if (IS_ERR(buffer))
290		return PTR_ERR(buffer);
291
292	fb = buffer->fb;
293
294	ret = drm_client_buffer_vmap(buffer, &map);
295	if (ret) {
296		goto err_drm_client_buffer_delete;
297	} else if (drm_WARN_ON(dev, map.is_iomem)) {
298		ret = -ENODEV; /* I/O memory not supported; use generic emulation */
299		goto err_drm_client_buffer_delete;
300	}
301
302	fb_helper->funcs = &drm_fbdev_dma_helper_funcs;
303	fb_helper->buffer = buffer;
304	fb_helper->fb = fb;
305
306	info = drm_fb_helper_alloc_info(fb_helper);
307	if (IS_ERR(info)) {
308		ret = PTR_ERR(info);
309		goto err_drm_client_buffer_vunmap;
310	}
311
312	drm_fb_helper_fill_info(info, fb_helper, sizes);
313
314	if (fb->funcs->dirty)
315		ret = drm_fbdev_dma_driver_fbdev_probe_tail_shadowed(fb_helper, sizes);
316	else
317		ret = drm_fbdev_dma_driver_fbdev_probe_tail(fb_helper, sizes);
318	if (ret)
319		goto err_drm_fb_helper_release_info;
320
321	return 0;
322
323err_drm_fb_helper_release_info:
324	drm_fb_helper_release_info(fb_helper);
325err_drm_client_buffer_vunmap:
326	fb_helper->fb = NULL;
327	fb_helper->buffer = NULL;
328	drm_client_buffer_vunmap(buffer);
329err_drm_client_buffer_delete:
330	drm_client_framebuffer_delete(buffer);
331	return ret;
332}
333EXPORT_SYMBOL(drm_fbdev_dma_driver_fbdev_probe);