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 */
 21static 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 - belnd 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 at vaddr_src on value
 54 * at vaddr_dst using buffer's metadata to locate the new values
 55 * from vaddr_src and their distenation at vaddr_dst.
 56 *
 57 * Todo: Use the alpha value to blend vaddr_src with vaddr_dst
 58 *	 instead of overwriting it.
 59 */
 60static 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
 94static 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
111static 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 */
151void 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
196static const char * const pipe_crc_sources[] = {"auto"};
197
198const 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
205static 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
221int 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
236int 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}