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_gem.h>
 11#include <drm/drm_print.h>
 12
 13#include <drm/drm_fbdev_ttm.h>
 14
 15/* @user: 1=userspace, 0=fbcon */
 16static int drm_fbdev_ttm_fb_open(struct fb_info *info, int user)
 17{
 18	struct drm_fb_helper *fb_helper = info->par;
 19
 20	/* No need to take a ref for fbcon because it unbinds on unregister */
 21	if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
 22		return -ENODEV;
 23
 24	return 0;
 25}
 26
 27static int drm_fbdev_ttm_fb_release(struct fb_info *info, int user)
 28{
 29	struct drm_fb_helper *fb_helper = info->par;
 30
 31	if (user)
 32		module_put(fb_helper->dev->driver->fops->owner);
 33
 34	return 0;
 35}
 36
 37FB_GEN_DEFAULT_DEFERRED_SYSMEM_OPS(drm_fbdev_ttm,
 38				   drm_fb_helper_damage_range,
 39				   drm_fb_helper_damage_area);
 40
 41static void drm_fbdev_ttm_fb_destroy(struct fb_info *info)
 42{
 43	struct drm_fb_helper *fb_helper = info->par;
 44	void *shadow = info->screen_buffer;
 45
 46	if (!fb_helper->dev)
 47		return;
 48
 49	fb_deferred_io_cleanup(info);
 50	drm_fb_helper_fini(fb_helper);
 51	vfree(shadow);
 52	drm_client_framebuffer_delete(fb_helper->buffer);
 53
 54	drm_client_release(&fb_helper->client);
 55	drm_fb_helper_unprepare(fb_helper);
 56	kfree(fb_helper);
 57}
 58
 59static const struct fb_ops drm_fbdev_ttm_fb_ops = {
 60	.owner		= THIS_MODULE,
 61	.fb_open	= drm_fbdev_ttm_fb_open,
 62	.fb_release	= drm_fbdev_ttm_fb_release,
 63	FB_DEFAULT_DEFERRED_OPS(drm_fbdev_ttm),
 64	DRM_FB_HELPER_DEFAULT_OPS,
 65	.fb_destroy	= drm_fbdev_ttm_fb_destroy,
 66};
 67
 68static void drm_fbdev_ttm_damage_blit_real(struct drm_fb_helper *fb_helper,
 69					   struct drm_clip_rect *clip,
 70					   struct iosys_map *dst)
 71{
 72	struct drm_framebuffer *fb = fb_helper->fb;
 73	size_t offset = clip->y1 * fb->pitches[0];
 74	size_t len = clip->x2 - clip->x1;
 75	unsigned int y;
 76	void *src;
 77
 78	switch (drm_format_info_bpp(fb->format, 0)) {
 79	case 1:
 80		offset += clip->x1 / 8;
 81		len = DIV_ROUND_UP(len + clip->x1 % 8, 8);
 82		break;
 83	case 2:
 84		offset += clip->x1 / 4;
 85		len = DIV_ROUND_UP(len + clip->x1 % 4, 4);
 86		break;
 87	case 4:
 88		offset += clip->x1 / 2;
 89		len = DIV_ROUND_UP(len + clip->x1 % 2, 2);
 90		break;
 91	default:
 92		offset += clip->x1 * fb->format->cpp[0];
 93		len *= fb->format->cpp[0];
 94		break;
 95	}
 96
 97	src = fb_helper->info->screen_buffer + offset;
 98	iosys_map_incr(dst, offset); /* go to first pixel within clip rect */
 99
100	for (y = clip->y1; y < clip->y2; y++) {
101		iosys_map_memcpy_to(dst, 0, src, len);
102		iosys_map_incr(dst, fb->pitches[0]);
103		src += fb->pitches[0];
104	}
105}
106
107static int drm_fbdev_ttm_damage_blit(struct drm_fb_helper *fb_helper,
108				     struct drm_clip_rect *clip)
109{
110	struct drm_client_buffer *buffer = fb_helper->buffer;
111	struct iosys_map map, dst;
112	int ret;
113
114	/*
115	 * We have to pin the client buffer to its current location while
116	 * flushing the shadow buffer. In the general case, concurrent
117	 * modesetting operations could try to move the buffer and would
118	 * fail. The modeset has to be serialized by acquiring the reservation
119	 * object of the underlying BO here.
120	 *
121	 * For fbdev emulation, we only have to protect against fbdev modeset
122	 * operations. Nothing else will involve the client buffer's BO. So it
123	 * is sufficient to acquire struct drm_fb_helper.lock here.
124	 */
125	mutex_lock(&fb_helper->lock);
126
127	ret = drm_client_buffer_vmap_local(buffer, &map);
128	if (ret)
129		goto out;
130
131	dst = map;
132	drm_fbdev_ttm_damage_blit_real(fb_helper, clip, &dst);
133
134	drm_client_buffer_vunmap_local(buffer);
135
136out:
137	mutex_unlock(&fb_helper->lock);
138
139	return ret;
140}
141
142static int drm_fbdev_ttm_helper_fb_dirty(struct drm_fb_helper *helper,
143					 struct drm_clip_rect *clip)
144{
145	struct drm_device *dev = helper->dev;
146	int ret;
147
148	/* Call damage handlers only if necessary */
149	if (!(clip->x1 < clip->x2 && clip->y1 < clip->y2))
150		return 0;
151
152	ret = drm_fbdev_ttm_damage_blit(helper, clip);
153	if (drm_WARN_ONCE(dev, ret, "Damage blitter failed: ret=%d\n", ret))
154		return ret;
155
156	if (helper->fb->funcs->dirty) {
157		ret = helper->fb->funcs->dirty(helper->fb, NULL, 0, 0, clip, 1);
158		if (drm_WARN_ONCE(dev, ret, "Dirty helper failed: ret=%d\n", ret))
159			return ret;
160	}
161
162	return 0;
163}
164
165static const struct drm_fb_helper_funcs drm_fbdev_ttm_helper_funcs = {
166	.fb_dirty = drm_fbdev_ttm_helper_fb_dirty,
167};
168
169/*
170 * struct drm_driver
171 */
172
173int drm_fbdev_ttm_driver_fbdev_probe(struct drm_fb_helper *fb_helper,
174				     struct drm_fb_helper_surface_size *sizes)
175{
176	struct drm_client_dev *client = &fb_helper->client;
177	struct drm_device *dev = fb_helper->dev;
178	struct drm_client_buffer *buffer;
179	struct fb_info *info;
180	size_t screen_size;
181	void *screen_buffer;
182	u32 format;
183	int ret;
184
185	drm_dbg_kms(dev, "surface width(%d), height(%d) and bpp(%d)\n",
186		    sizes->surface_width, sizes->surface_height,
187		    sizes->surface_bpp);
188
189	format = drm_driver_legacy_fb_format(dev, sizes->surface_bpp,
190					     sizes->surface_depth);
191	buffer = drm_client_framebuffer_create(client, sizes->surface_width,
192					       sizes->surface_height, format);
193	if (IS_ERR(buffer))
194		return PTR_ERR(buffer);
195
196	fb_helper->funcs = &drm_fbdev_ttm_helper_funcs;
197	fb_helper->buffer = buffer;
198	fb_helper->fb = buffer->fb;
199
200	screen_size = buffer->gem->size;
201	screen_buffer = vzalloc(screen_size);
202	if (!screen_buffer) {
203		ret = -ENOMEM;
204		goto err_drm_client_framebuffer_delete;
205	}
206
207	info = drm_fb_helper_alloc_info(fb_helper);
208	if (IS_ERR(info)) {
209		ret = PTR_ERR(info);
210		goto err_vfree;
211	}
212
213	drm_fb_helper_fill_info(info, fb_helper, sizes);
214
215	info->fbops = &drm_fbdev_ttm_fb_ops;
216
217	/* screen */
218	info->flags |= FBINFO_VIRTFB | FBINFO_READS_FAST;
219	info->screen_buffer = screen_buffer;
220	info->fix.smem_len = screen_size;
221
222	/* deferred I/O */
223	fb_helper->fbdefio.delay = HZ / 20;
224	fb_helper->fbdefio.deferred_io = drm_fb_helper_deferred_io;
225
226	info->fbdefio = &fb_helper->fbdefio;
227	ret = fb_deferred_io_init(info);
228	if (ret)
229		goto err_drm_fb_helper_release_info;
230
231	return 0;
232
233err_drm_fb_helper_release_info:
234	drm_fb_helper_release_info(fb_helper);
235err_vfree:
236	vfree(screen_buffer);
237err_drm_client_framebuffer_delete:
238	fb_helper->fb = NULL;
239	fb_helper->buffer = NULL;
240	drm_client_framebuffer_delete(buffer);
241	return ret;
242}
243EXPORT_SYMBOL(drm_fbdev_ttm_driver_fbdev_probe);