1// SPDX-License-Identifier: MIT
  2
  3#include <linux/moduleparam.h>
  4#include <linux/vmalloc.h>
  5
  6#include <drm/drm_crtc_helper.h>
  7#include <drm/drm_drv.h>
  8#include <drm/drm_fb_helper.h>
  9#include <drm/drm_framebuffer.h>
 10#include <drm/drm_print.h>
 11
 12#include <drm/drm_fbdev_generic.h>
 13
 14static bool drm_fbdev_use_shadow_fb(struct drm_fb_helper *fb_helper)
 15{
 16	struct drm_device *dev = fb_helper->dev;
 17	struct drm_framebuffer *fb = fb_helper->fb;
 18
 19	return dev->mode_config.prefer_shadow_fbdev ||
 20	       dev->mode_config.prefer_shadow ||
 21	       fb->funcs->dirty;
 22}
 23
 24/* @user: 1=userspace, 0=fbcon */
 25static int drm_fbdev_fb_open(struct fb_info *info, int user)
 26{
 27	struct drm_fb_helper *fb_helper = info->par;
 28
 29	/* No need to take a ref for fbcon because it unbinds on unregister */
 30	if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
 31		return -ENODEV;
 32
 33	return 0;
 34}
 35
 36static int drm_fbdev_fb_release(struct fb_info *info, int user)
 37{
 38	struct drm_fb_helper *fb_helper = info->par;
 39
 40	if (user)
 41		module_put(fb_helper->dev->driver->fops->owner);
 42
 43	return 0;
 44}
 45
 46static void drm_fbdev_cleanup(struct drm_fb_helper *fb_helper)
 47{
 48	struct fb_info *fbi = fb_helper->info;
 49	void *shadow = NULL;
 50
 51	if (!fb_helper->dev)
 52		return;
 53
 54	if (fbi) {
 55		if (fbi->fbdefio)
 56			fb_deferred_io_cleanup(fbi);
 57		if (drm_fbdev_use_shadow_fb(fb_helper))
 58			shadow = fbi->screen_buffer;
 59	}
 60
 61	drm_fb_helper_fini(fb_helper);
 62
 63	if (shadow)
 64		vfree(shadow);
 65	else if (fb_helper->buffer)
 66		drm_client_buffer_vunmap(fb_helper->buffer);
 67
 68	drm_client_framebuffer_delete(fb_helper->buffer);
 69}
 70
 71static void drm_fbdev_release(struct drm_fb_helper *fb_helper)
 72{
 73	drm_fbdev_cleanup(fb_helper);
 74	drm_client_release(&fb_helper->client);
 75	kfree(fb_helper);
 76}
 77
 78/*
 79 * fb_ops.fb_destroy is called by the last put_fb_info() call at the end of
 80 * unregister_framebuffer() or fb_release().
 81 */
 82static void drm_fbdev_fb_destroy(struct fb_info *info)
 83{
 84	drm_fbdev_release(info->par);
 85}
 86
 87static int drm_fbdev_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 88{
 89	struct drm_fb_helper *fb_helper = info->par;
 90
 91	if (drm_fbdev_use_shadow_fb(fb_helper))
 92		return fb_deferred_io_mmap(info, vma);
 93	else if (fb_helper->dev->driver->gem_prime_mmap)
 94		return fb_helper->dev->driver->gem_prime_mmap(fb_helper->buffer->gem, vma);
 95	else
 96		return -ENODEV;
 97}
 98
 99static bool drm_fbdev_use_iomem(struct fb_info *info)
100{
101	struct drm_fb_helper *fb_helper = info->par;
102	struct drm_client_buffer *buffer = fb_helper->buffer;
103
104	return !drm_fbdev_use_shadow_fb(fb_helper) && buffer->map.is_iomem;
105}
106
107static ssize_t drm_fbdev_fb_read(struct fb_info *info, char __user *buf,
108				 size_t count, loff_t *ppos)
109{
110	ssize_t ret;
111
112	if (drm_fbdev_use_iomem(info))
113		ret = drm_fb_helper_cfb_read(info, buf, count, ppos);
114	else
115		ret = drm_fb_helper_sys_read(info, buf, count, ppos);
116
117	return ret;
118}
119
120static ssize_t drm_fbdev_fb_write(struct fb_info *info, const char __user *buf,
121				  size_t count, loff_t *ppos)
122{
123	ssize_t ret;
124
125	if (drm_fbdev_use_iomem(info))
126		ret = drm_fb_helper_cfb_write(info, buf, count, ppos);
127	else
128		ret = drm_fb_helper_sys_write(info, buf, count, ppos);
129
130	return ret;
131}
132
133static void drm_fbdev_fb_fillrect(struct fb_info *info,
134				  const struct fb_fillrect *rect)
135{
136	if (drm_fbdev_use_iomem(info))
137		drm_fb_helper_cfb_fillrect(info, rect);
138	else
139		drm_fb_helper_sys_fillrect(info, rect);
140}
141
142static void drm_fbdev_fb_copyarea(struct fb_info *info,
143				  const struct fb_copyarea *area)
144{
145	if (drm_fbdev_use_iomem(info))
146		drm_fb_helper_cfb_copyarea(info, area);
147	else
148		drm_fb_helper_sys_copyarea(info, area);
149}
150
151static void drm_fbdev_fb_imageblit(struct fb_info *info,
152				   const struct fb_image *image)
153{
154	if (drm_fbdev_use_iomem(info))
155		drm_fb_helper_cfb_imageblit(info, image);
156	else
157		drm_fb_helper_sys_imageblit(info, image);
158}
159
160static const struct fb_ops drm_fbdev_fb_ops = {
161	.owner		= THIS_MODULE,
162	DRM_FB_HELPER_DEFAULT_OPS,
163	.fb_open	= drm_fbdev_fb_open,
164	.fb_release	= drm_fbdev_fb_release,
165	.fb_destroy	= drm_fbdev_fb_destroy,
166	.fb_mmap	= drm_fbdev_fb_mmap,
167	.fb_read	= drm_fbdev_fb_read,
168	.fb_write	= drm_fbdev_fb_write,
169	.fb_fillrect	= drm_fbdev_fb_fillrect,
170	.fb_copyarea	= drm_fbdev_fb_copyarea,
171	.fb_imageblit	= drm_fbdev_fb_imageblit,
172};
173
174/*
175 * This function uses the client API to create a framebuffer backed by a dumb buffer.
176 */
177static int drm_fbdev_fb_probe(struct drm_fb_helper *fb_helper,
178			      struct drm_fb_helper_surface_size *sizes)
179{
180	struct drm_client_dev *client = &fb_helper->client;
181	struct drm_device *dev = fb_helper->dev;
182	struct drm_client_buffer *buffer;
183	struct drm_framebuffer *fb;
184	struct fb_info *fbi;
185	u32 format;
186	struct iosys_map map;
187	int ret;
188
189	drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
190		    sizes->surface_width, sizes->surface_height,
191		    sizes->surface_bpp);
192
193	format = drm_mode_legacy_fb_format(sizes->surface_bpp, sizes->surface_depth);
194	buffer = drm_client_framebuffer_create(client, sizes->surface_width,
195					       sizes->surface_height, format);
196	if (IS_ERR(buffer))
197		return PTR_ERR(buffer);
198
199	fb_helper->buffer = buffer;
200	fb_helper->fb = buffer->fb;
201	fb = buffer->fb;
202
203	fbi = drm_fb_helper_alloc_info(fb_helper);
204	if (IS_ERR(fbi))
205		return PTR_ERR(fbi);
206
207	fbi->fbops = &drm_fbdev_fb_ops;
208	fbi->screen_size = sizes->surface_height * fb->pitches[0];
209	fbi->fix.smem_len = fbi->screen_size;
210	fbi->flags = FBINFO_DEFAULT;
211
212	drm_fb_helper_fill_info(fbi, fb_helper, sizes);
213
214	if (drm_fbdev_use_shadow_fb(fb_helper)) {
215		fbi->screen_buffer = vzalloc(fbi->screen_size);
216		if (!fbi->screen_buffer)
217			return -ENOMEM;
218		fbi->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
219
220		/* Set a default deferred I/O handler */
221		fb_helper->fbdefio.delay = HZ / 20;
222		fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
223
224		fbi->fbdefio = &fb_helper->fbdefio;
225		ret = fb_deferred_io_init(fbi);
226		if (ret)
227			return ret;
228	} else {
229		/* buffer is mapped for HW framebuffer */
230		ret = drm_client_buffer_vmap(fb_helper->buffer, &map);
231		if (ret)
232			return ret;
233		if (map.is_iomem) {
234			fbi->screen_base = map.vaddr_iomem;
235		} else {
236			fbi->screen_buffer = map.vaddr;
237			fbi->flags |= FBINFO_VIRTFB;
238		}
239
240		/*
241		 * Shamelessly leak the physical address to user-space. As
242		 * page_to_phys() is undefined for I/O memory, warn in this
243		 * case.
244		 */
245#if IS_ENABLED(CONFIG_DRM_FBDEV_LEAK_PHYS_SMEM)
246		if (fb_helper->hint_leak_smem_start && fbi->fix.smem_start == 0 &&
247		    !drm_WARN_ON_ONCE(dev, map.is_iomem))
248			fbi->fix.smem_start =
249				page_to_phys(virt_to_page(fbi->screen_buffer));
250#endif
251	}
252
253	return 0;
254}
255
256static void drm_fbdev_damage_blit_real(struct drm_fb_helper *fb_helper,
257				       struct drm_clip_rect *clip,
258				       struct iosys_map *dst)
259{
260	struct drm_framebuffer *fb = fb_helper->fb;
261	size_t offset = clip->y1 * fb->pitches[0];
262	size_t len = clip->x2 - clip->x1;
263	unsigned int y;
264	void *src;
265
266	switch (drm_format_info_bpp(fb->format, 0)) {
267	case 1:
268		offset += clip->x1 / 8;
269		len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
270		break;
271	case 2:
272		offset += clip->x1 / 4;
273		len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
274		break;
275	case 4:
276		offset += clip->x1 / 2;
277		len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
278		break;
279	default:
280		offset += clip->x1 * fb->format->cpp[0];
281		len *= fb->format->cpp[0];
282		break;
283	}
284
285	src = fb_helper->info->screen_buffer + offset;
286	iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
287
288	for (y = clip->y1; y < clip->y2; y++) {
289		iosys_map_memcpy_to(dst, 0, src, len);
290		iosys_map_incr(dst, fb->pitches[0]);
291		src += fb->pitches[0];
292	}
293}
294
295static int drm_fbdev_damage_blit(struct drm_fb_helper *fb_helper,
296				 struct drm_clip_rect *clip)
297{
298	struct drm_client_buffer *buffer = fb_helper->buffer;
299	struct iosys_map map, dst;
300	int ret;
301
302	/*
303	 * We have to pin the client buffer to its current location while
304	 * flushing the shadow buffer. In the general case, concurrent
305	 * modesetting operations could try to move the buffer and would
306	 * fail. The modeset has to be serialized by acquiring the reservation
307	 * object of the underlying BO here.
308	 *
309	 * For fbdev emulation, we only have to protect against fbdev modeset
310	 * operations. Nothing else will involve the client buffer's BO. So it
311	 * is sufficient to acquire struct drm_fb_helper.lock here.
312	 */
313	mutex_lock(&fb_helper->lock);
314
315	ret = drm_client_buffer_vmap(buffer, &map);
316	if (ret)
317		goto out;
318
319	dst = map;
320	drm_fbdev_damage_blit_real(fb_helper, clip, &dst);
321
322	drm_client_buffer_vunmap(buffer);
323
324out:
325	mutex_unlock(&fb_helper->lock);
326
327	return ret;
328}
329
330static int drm_fbdev_fb_dirty(struct drm_fb_helper *helper, struct drm_clip_rect *clip)
331{
332	struct drm_device *dev = helper->dev;
333	int ret;
334
335	if (!drm_fbdev_use_shadow_fb(helper))
336		return 0;
337
338	/* Call damage handlers only if necessary */
339	if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
340		return 0;
341
342	if (helper->buffer) {
343		ret = drm_fbdev_damage_blit(helper, clip);
344		if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
345			return ret;
346	}
347
348	if (helper->fb->funcs->dirty) {
349		ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
350		if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
351			return ret;
352	}
353
354	return 0;
355}
356
357static const struct drm_fb_helper_funcs drm_fb_helper_generic_funcs = {
358	.fb_probe = drm_fbdev_fb_probe,
359	.fb_dirty = drm_fbdev_fb_dirty,
360};
361
362static void drm_fbdev_client_unregister(struct drm_client_dev *client)
363{
364	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
365
366	if (fb_helper->info)
367		/* drm_fbdev_fb_destroy() takes care of cleanup */
368		drm_fb_helper_unregister_info(fb_helper);
369	else
370		drm_fbdev_release(fb_helper);
371}
372
373static int drm_fbdev_client_restore(struct drm_client_dev *client)
374{
375	drm_fb_helper_lastclose(client->dev);
376
377	return 0;
378}
379
380static int drm_fbdev_client_hotplug(struct drm_client_dev *client)
381{
382	struct drm_fb_helper *fb_helper = drm_fb_helper_from_client(client);
383	struct drm_device *dev = client->dev;
384	int ret;
385
386	/* Setup is not retried if it has failed */
387	if (!fb_helper->dev && fb_helper->funcs)
388		return 0;
389
390	if (dev->fb_helper)
391		return drm_fb_helper_hotplug_event(dev->fb_helper);
392
393	if (!dev->mode_config.num_connector) {
394		drm_dbg_kms(dev, "No connectors found, will not create framebuffer!\n");
395		return 0;
396	}
397
398	drm_fb_helper_prepare(dev, fb_helper, &drm_fb_helper_generic_funcs);
399
400	ret = drm_fb_helper_init(dev, fb_helper);
401	if (ret)
402		goto err;
403
404	if (!drm_drv_uses_atomic_modeset(dev))
405		drm_helper_disable_unused_functions(dev);
406
407	ret = drm_fb_helper_initial_config(fb_helper, fb_helper->preferred_bpp);
408	if (ret)
409		goto err_cleanup;
410
411	return 0;
412
413err_cleanup:
414	drm_fbdev_cleanup(fb_helper);
415err:
416	fb_helper->dev = NULL;
417	fb_helper->info = NULL;
418
419	drm_err(dev, "fbdev: Failed to setup generic emulation (ret=%d)\n", ret);
420
421	return ret;
422}
423
424static const struct drm_client_funcs drm_fbdev_client_funcs = {
425	.owner		= THIS_MODULE,
426	.unregister	= drm_fbdev_client_unregister,
427	.restore	= drm_fbdev_client_restore,
428	.hotplug	= drm_fbdev_client_hotplug,
429};
430
431/**
432 * drm_fbdev_generic_setup() - Setup generic fbdev emulation
433 * @dev: DRM device
434 * @preferred_bpp: Preferred bits per pixel for the device.
435 *                 @dev->mode_config.preferred_depth is used if this is zero.
436 *
437 * This function sets up generic fbdev emulation for drivers that supports
438 * dumb buffers with a virtual address and that can be mmap'ed.
439 * drm_fbdev_generic_setup() shall be called after the DRM driver registered
440 * the new DRM device with drm_dev_register().
441 *
442 * Restore, hotplug events and teardown are all taken care of. Drivers that do
443 * suspend/resume need to call drm_fb_helper_set_suspend_unlocked() themselves.
444 * Simple drivers might use drm_mode_config_helper_suspend().
445 *
446 * Drivers that set the dirty callback on their framebuffer will get a shadow
447 * fbdev buffer that is blitted onto the real buffer. This is done in order to
448 * make deferred I/O work with all kinds of buffers. A shadow buffer can be
449 * requested explicitly by setting struct drm_mode_config.prefer_shadow or
450 * struct drm_mode_config.prefer_shadow_fbdev to true beforehand. This is
451 * required to use generic fbdev emulation with SHMEM helpers.
452 *
453 * This function is safe to call even when there are no connectors present.
454 * Setup will be retried on the next hotplug event.
455 *
456 * The fbdev is destroyed by drm_dev_unregister().
457 */
458void drm_fbdev_generic_setup(struct drm_device *dev,
459			     unsigned int preferred_bpp)
460{
461	struct drm_fb_helper *fb_helper;
462	int ret;
463
464	drm_WARN(dev, !dev->registered, "Device has not been registered.\n");
465	drm_WARN(dev, dev->fb_helper, "fb_helper is already set!\n");
466
467	fb_helper = kzalloc(sizeof(*fb_helper), GFP_KERNEL);
468	if (!fb_helper)
469		return;
470
471	ret = drm_client_init(dev, &fb_helper->client, "fbdev", &drm_fbdev_client_funcs);
472	if (ret) {
473		kfree(fb_helper);
474		drm_err(dev, "Failed to register client: %d\n", ret);
475		return;
476	}
477
478	/*
479	 * FIXME: This mixes up depth with bpp, which results in a glorious
480	 * mess, resulting in some drivers picking wrong fbdev defaults and
481	 * others wrong preferred_depth defaults.
482	 */
483	if (!preferred_bpp)
484		preferred_bpp = dev->mode_config.preferred_depth;
485	if (!preferred_bpp)
486		preferred_bpp = 32;
487	fb_helper->preferred_bpp = preferred_bpp;
488
489	ret = drm_fbdev_client_hotplug(&fb_helper->client);
490	if (ret)
491		drm_dbg_kms(dev, "client hotplug ret=%d\n", ret);
492
493	drm_client_register(&fb_helper->client);
494}
495EXPORT_SYMBOL(drm_fbdev_generic_setup);