1 // SPDX-License-Identifier: GPL-2.0+
2 
3 #include <linux/crc32.h>
4 
5 #include <drm/drm_atomic.h>
6 #include <drm/drm_atomic_helper.h>
7 #include <drm/drm_gem_framebuffer_helper.h>
8 #include <drm/drm_vblank.h>
9 
10 #include "vkms_drv.h"
11 
12 /**
13  * compute_crc - Compute CRC value on output frame
14  *
15  * @vaddr_out: address to final framebuffer
16  * @composer: framebuffer's metadata
17  *
18  * returns CRC value computed using crc32 on the visible portion of
19  * the final framebuffer at vaddr_out
20  */
21 static uint32_t compute_crc(void *vaddr_out, struct vkms_composer *composer)
22 {
23 	int i, j, src_offset;
24 	int x_src = composer->src.x1 >> 16;
25 	int y_src = composer->src.y1 >> 16;
26 	int h_src = drm_rect_height(&composer->src) >> 16;
27 	int w_src = drm_rect_width(&composer->src) >> 16;
28 	u32 crc = 0;
29 
30 	for (i = y_src; i < y_src + h_src; ++i) {
31 		for (j = x_src; j < x_src + w_src; ++j) {
32 			src_offset = composer->offset
33 				     + (i * composer->pitch)
34 				     + (j * composer->cpp);
35 			/* XRGB format ignores Alpha channel */
36 			memset(vaddr_out + src_offset + 24, 0,  8);
37 			crc = crc32_le(crc, vaddr_out + src_offset,
38 				       sizeof(u32));
39 		}
40 	}
41 
42 	return crc;
43 }
44 
45 /**
46  * blend - blend value at vaddr_src with value at vaddr_dst
47  * @vaddr_dst: destination address
48  * @vaddr_src: source address
49  * @dest_composer: destination framebuffer's metadata
50  * @src_composer: source framebuffer's metadata
51  *
52  * Blend value at vaddr_src with value at vaddr_dst.
53  * Currently, this function write value of vaddr_src on value
54  * at vaddr_dst using buffer's metadata to locate the new values
55  * from vaddr_src and their destination at vaddr_dst.
56  *
57  * TODO: Use the alpha value to blend vaddr_src with vaddr_dst
58  *	 instead of overwriting it.
59  */
60 static void blend(void *vaddr_dst, void *vaddr_src,
61 		  struct vkms_composer *dest_composer,
62 		  struct vkms_composer *src_composer)
63 {
64 	int i, j, j_dst, i_dst;
65 	int offset_src, offset_dst;
66 
67 	int x_src = src_composer->src.x1 >> 16;
68 	int y_src = src_composer->src.y1 >> 16;
69 
70 	int x_dst = src_composer->dst.x1;
71 	int y_dst = src_composer->dst.y1;
72 	int h_dst = drm_rect_height(&src_composer->dst);
73 	int w_dst = drm_rect_width(&src_composer->dst);
74 
75 	int y_limit = y_src + h_dst;
76 	int x_limit = x_src + w_dst;
77 
78 	for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
79 		for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
80 			offset_dst = dest_composer->offset
81 				     + (i_dst * dest_composer->pitch)
82 				     + (j_dst++ * dest_composer->cpp);
83 			offset_src = src_composer->offset
84 				     + (i * src_composer->pitch)
85 				     + (j * src_composer->cpp);
86 
87 			memcpy(vaddr_dst + offset_dst,
88 			       vaddr_src + offset_src, sizeof(u32));
89 		}
90 		i_dst++;
91 	}
92 }
93 
94 static void compose_cursor(struct vkms_composer *cursor_composer,
95 			   struct vkms_composer *primary_composer,
96 			   void *vaddr_out)
97 {
98 	struct drm_gem_object *cursor_obj;
99 	struct vkms_gem_object *cursor_vkms_obj;
100 
101 	cursor_obj = drm_gem_fb_get_obj(&cursor_composer->fb, 0);
102 	cursor_vkms_obj = drm_gem_to_vkms_gem(cursor_obj);
103 
104 	if (WARN_ON(!cursor_vkms_obj->vaddr))
105 		return;
106 
107 	blend(vaddr_out, cursor_vkms_obj->vaddr,
108 	      primary_composer, cursor_composer);
109 }
110 
111 static uint32_t _vkms_get_crc(struct vkms_composer *primary_composer,
112 			      struct vkms_composer *cursor_composer)
113 {
114 	struct drm_framebuffer *fb = &primary_composer->fb;
115 	struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
116 	struct vkms_gem_object *vkms_obj = drm_gem_to_vkms_gem(gem_obj);
117 	void *vaddr_out = kzalloc(vkms_obj->gem.size, GFP_KERNEL);
118 	u32 crc = 0;
119 
120 	if (!vaddr_out) {
121 		DRM_ERROR("Failed to allocate memory for output frame.");
122 		return 0;
123 	}
124 
125 	if (WARN_ON(!vkms_obj->vaddr)) {
126 		kfree(vaddr_out);
127 		return crc;
128 	}
129 
130 	memcpy(vaddr_out, vkms_obj->vaddr, vkms_obj->gem.size);
131 
132 	if (cursor_composer)
133 		compose_cursor(cursor_composer, primary_composer, vaddr_out);
134 
135 	crc = compute_crc(vaddr_out, primary_composer);
136 
137 	kfree(vaddr_out);
138 
139 	return crc;
140 }
141 
142 /**
143  * vkms_composer_worker - ordered work_struct to compute CRC
144  *
145  * @work: work_struct
146  *
147  * Work handler for composing and computing CRCs. work_struct scheduled in
148  * an ordered workqueue that's periodically scheduled to run by
149  * _vblank_handle() and flushed at vkms_atomic_crtc_destroy_state().
150  */
151 void vkms_composer_worker(struct work_struct *work)
152 {
153 	struct vkms_crtc_state *crtc_state = container_of(work,
154 						struct vkms_crtc_state,
155 						composer_work);
156 	struct drm_crtc *crtc = crtc_state->base.crtc;
157 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
158 	struct vkms_composer *primary_composer = NULL;
159 	struct vkms_composer *cursor_composer = NULL;
160 	u32 crc32 = 0;
161 	u64 frame_start, frame_end;
162 	bool crc_pending;
163 
164 	spin_lock_irq(&out->composer_lock);
165 	frame_start = crtc_state->frame_start;
166 	frame_end = crtc_state->frame_end;
167 	crc_pending = crtc_state->crc_pending;
168 	crtc_state->frame_start = 0;
169 	crtc_state->frame_end = 0;
170 	crtc_state->crc_pending = false;
171 	spin_unlock_irq(&out->composer_lock);
172 
173 	/*
174 	 * We raced with the vblank hrtimer and previous work already computed
175 	 * the crc, nothing to do.
176 	 */
177 	if (!crc_pending)
178 		return;
179 
180 	if (crtc_state->num_active_planes >= 1)
181 		primary_composer = crtc_state->active_planes[0]->composer;
182 
183 	if (crtc_state->num_active_planes == 2)
184 		cursor_composer = crtc_state->active_planes[1]->composer;
185 
186 	if (primary_composer)
187 		crc32 = _vkms_get_crc(primary_composer, cursor_composer);
188 
189 	/*
190 	 * The worker can fall behind the vblank hrtimer, make sure we catch up.
191 	 */
192 	while (frame_start <= frame_end)
193 		drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
194 }
195 
196 static const char * const pipe_crc_sources[] = {"auto"};
197 
198 const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
199 					size_t *count)
200 {
201 	*count = ARRAY_SIZE(pipe_crc_sources);
202 	return pipe_crc_sources;
203 }
204 
205 static int vkms_crc_parse_source(const char *src_name, bool *enabled)
206 {
207 	int ret = 0;
208 
209 	if (!src_name) {
210 		*enabled = false;
211 	} else if (strcmp(src_name, "auto") == 0) {
212 		*enabled = true;
213 	} else {
214 		*enabled = false;
215 		ret = -EINVAL;
216 	}
217 
218 	return ret;
219 }
220 
221 int vkms_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
222 			   size_t *values_cnt)
223 {
224 	bool enabled;
225 
226 	if (vkms_crc_parse_source(src_name, &enabled) < 0) {
227 		DRM_DEBUG_DRIVER("unknown source %s\n", src_name);
228 		return -EINVAL;
229 	}
230 
231 	*values_cnt = 1;
232 
233 	return 0;
234 }
235 
236 int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name)
237 {
238 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
239 	bool enabled = false;
240 	int ret = 0;
241 
242 	ret = vkms_crc_parse_source(src_name, &enabled);
243 
244 	spin_lock_irq(&out->lock);
245 	out->composer_enabled = enabled;
246 	spin_unlock_irq(&out->lock);
247 
248 	return ret;
249 }
250