1 // SPDX-License-Identifier: GPL-2.0+
2 
3 #include <linux/dma-fence.h>
4 
5 #include <drm/drm_atomic.h>
6 #include <drm/drm_atomic_helper.h>
7 #include <drm/drm_probe_helper.h>
8 #include <drm/drm_vblank.h>
9 
10 #include "vkms_drv.h"
11 
vkms_vblank_simulate(struct hrtimer * timer)12 static enum hrtimer_restart vkms_vblank_simulate(struct hrtimer *timer)
13 {
14 	struct vkms_output *output = container_of(timer, struct vkms_output,
15 						  vblank_hrtimer);
16 	struct drm_crtc *crtc = &output->crtc;
17 	struct vkms_crtc_state *state;
18 	u64 ret_overrun;
19 	bool ret, fence_cookie;
20 
21 	fence_cookie = dma_fence_begin_signalling();
22 
23 	ret_overrun = hrtimer_forward_now(&output->vblank_hrtimer,
24 					  output->period_ns);
25 	if (ret_overrun != 1)
26 		pr_warn("%s: vblank timer overrun\n", __func__);
27 
28 	spin_lock(&output->lock);
29 	ret = drm_crtc_handle_vblank(crtc);
30 	if (!ret)
31 		DRM_ERROR("vkms failure on handling vblank");
32 
33 	state = output->composer_state;
34 	spin_unlock(&output->lock);
35 
36 	if (state && output->composer_enabled) {
37 		u64 frame = drm_crtc_accurate_vblank_count(crtc);
38 
39 		/* update frame_start only if a queued vkms_composer_worker()
40 		 * has read the data
41 		 */
42 		spin_lock(&output->composer_lock);
43 		if (!state->crc_pending)
44 			state->frame_start = frame;
45 		else
46 			DRM_DEBUG_DRIVER("crc worker falling behind, frame_start: %llu, frame_end: %llu\n",
47 					 state->frame_start, frame);
48 		state->frame_end = frame;
49 		state->crc_pending = true;
50 		spin_unlock(&output->composer_lock);
51 
52 		ret = queue_work(output->composer_workq, &state->composer_work);
53 		if (!ret)
54 			DRM_DEBUG_DRIVER("Composer worker already queued\n");
55 	}
56 
57 	dma_fence_end_signalling(fence_cookie);
58 
59 	return HRTIMER_RESTART;
60 }
61 
vkms_enable_vblank(struct drm_crtc * crtc)62 static int vkms_enable_vblank(struct drm_crtc *crtc)
63 {
64 	struct drm_device *dev = crtc->dev;
65 	unsigned int pipe = drm_crtc_index(crtc);
66 	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
67 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
68 
69 	drm_calc_timestamping_constants(crtc, &crtc->mode);
70 
71 	hrtimer_init(&out->vblank_hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
72 	out->vblank_hrtimer.function = &vkms_vblank_simulate;
73 	out->period_ns = ktime_set(0, vblank->framedur_ns);
74 	hrtimer_start(&out->vblank_hrtimer, out->period_ns, HRTIMER_MODE_REL);
75 
76 	return 0;
77 }
78 
vkms_disable_vblank(struct drm_crtc * crtc)79 static void vkms_disable_vblank(struct drm_crtc *crtc)
80 {
81 	struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
82 
83 	hrtimer_cancel(&out->vblank_hrtimer);
84 }
85 
vkms_get_vblank_timestamp(struct drm_crtc * crtc,int * max_error,ktime_t * vblank_time,bool in_vblank_irq)86 static bool vkms_get_vblank_timestamp(struct drm_crtc *crtc,
87 				      int *max_error, ktime_t *vblank_time,
88 				      bool in_vblank_irq)
89 {
90 	struct drm_device *dev = crtc->dev;
91 	unsigned int pipe = crtc->index;
92 	struct vkms_device *vkmsdev = drm_device_to_vkms_device(dev);
93 	struct vkms_output *output = &vkmsdev->output;
94 	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
95 
96 	if (!READ_ONCE(vblank->enabled)) {
97 		*vblank_time = ktime_get();
98 		return true;
99 	}
100 
101 	*vblank_time = READ_ONCE(output->vblank_hrtimer.node.expires);
102 
103 	if (WARN_ON(*vblank_time == vblank->time))
104 		return true;
105 
106 	/*
107 	 * To prevent races we roll the hrtimer forward before we do any
108 	 * interrupt processing - this is how real hw works (the interrupt is
109 	 * only generated after all the vblank registers are updated) and what
110 	 * the vblank core expects. Therefore we need to always correct the
111 	 * timestampe by one frame.
112 	 */
113 	*vblank_time -= output->period_ns;
114 
115 	return true;
116 }
117 
118 static struct drm_crtc_state *
vkms_atomic_crtc_duplicate_state(struct drm_crtc * crtc)119 vkms_atomic_crtc_duplicate_state(struct drm_crtc *crtc)
120 {
121 	struct vkms_crtc_state *vkms_state;
122 
123 	if (WARN_ON(!crtc->state))
124 		return NULL;
125 
126 	vkms_state = kzalloc(sizeof(*vkms_state), GFP_KERNEL);
127 	if (!vkms_state)
128 		return NULL;
129 
130 	__drm_atomic_helper_crtc_duplicate_state(crtc, &vkms_state->base);
131 
132 	INIT_WORK(&vkms_state->composer_work, vkms_composer_worker);
133 
134 	return &vkms_state->base;
135 }
136 
vkms_atomic_crtc_destroy_state(struct drm_crtc * crtc,struct drm_crtc_state * state)137 static void vkms_atomic_crtc_destroy_state(struct drm_crtc *crtc,
138 					   struct drm_crtc_state *state)
139 {
140 	struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(state);
141 
142 	__drm_atomic_helper_crtc_destroy_state(state);
143 
144 	WARN_ON(work_pending(&vkms_state->composer_work));
145 	kfree(vkms_state->active_planes);
146 	kfree(vkms_state);
147 }
148 
vkms_atomic_crtc_reset(struct drm_crtc * crtc)149 static void vkms_atomic_crtc_reset(struct drm_crtc *crtc)
150 {
151 	struct vkms_crtc_state *vkms_state =
152 		kzalloc(sizeof(*vkms_state), GFP_KERNEL);
153 
154 	if (crtc->state)
155 		vkms_atomic_crtc_destroy_state(crtc, crtc->state);
156 
157 	__drm_atomic_helper_crtc_reset(crtc, &vkms_state->base);
158 	if (vkms_state)
159 		INIT_WORK(&vkms_state->composer_work, vkms_composer_worker);
160 }
161 
162 static const struct drm_crtc_funcs vkms_crtc_funcs = {
163 	.set_config             = drm_atomic_helper_set_config,
164 	.destroy                = drm_crtc_cleanup,
165 	.page_flip              = drm_atomic_helper_page_flip,
166 	.reset                  = vkms_atomic_crtc_reset,
167 	.atomic_duplicate_state = vkms_atomic_crtc_duplicate_state,
168 	.atomic_destroy_state   = vkms_atomic_crtc_destroy_state,
169 	.enable_vblank		= vkms_enable_vblank,
170 	.disable_vblank		= vkms_disable_vblank,
171 	.get_vblank_timestamp	= vkms_get_vblank_timestamp,
172 	.get_crc_sources	= vkms_get_crc_sources,
173 	.set_crc_source		= vkms_set_crc_source,
174 	.verify_crc_source	= vkms_verify_crc_source,
175 };
176 
vkms_crtc_atomic_check(struct drm_crtc * crtc,struct drm_atomic_state * state)177 static int vkms_crtc_atomic_check(struct drm_crtc *crtc,
178 				  struct drm_atomic_state *state)
179 {
180 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state,
181 									  crtc);
182 	struct vkms_crtc_state *vkms_state = to_vkms_crtc_state(crtc_state);
183 	struct drm_plane *plane;
184 	struct drm_plane_state *plane_state;
185 	int i = 0, ret;
186 
187 	if (vkms_state->active_planes)
188 		return 0;
189 
190 	ret = drm_atomic_add_affected_planes(crtc_state->state, crtc);
191 	if (ret < 0)
192 		return ret;
193 
194 	drm_for_each_plane_mask(plane, crtc->dev, crtc_state->plane_mask) {
195 		plane_state = drm_atomic_get_existing_plane_state(crtc_state->state,
196 								  plane);
197 		WARN_ON(!plane_state);
198 
199 		if (!plane_state->visible)
200 			continue;
201 
202 		i++;
203 	}
204 
205 	vkms_state->active_planes = kcalloc(i, sizeof(plane), GFP_KERNEL);
206 	if (!vkms_state->active_planes)
207 		return -ENOMEM;
208 	vkms_state->num_active_planes = i;
209 
210 	i = 0;
211 	drm_for_each_plane_mask(plane, crtc->dev, crtc_state->plane_mask) {
212 		plane_state = drm_atomic_get_existing_plane_state(crtc_state->state,
213 								  plane);
214 
215 		if (!plane_state->visible)
216 			continue;
217 
218 		vkms_state->active_planes[i++] =
219 			to_vkms_plane_state(plane_state);
220 	}
221 
222 	return 0;
223 }
224 
vkms_crtc_atomic_enable(struct drm_crtc * crtc,struct drm_atomic_state * state)225 static void vkms_crtc_atomic_enable(struct drm_crtc *crtc,
226 				    struct drm_atomic_state *state)
227 {
228 	drm_crtc_vblank_on(crtc);
229 }
230 
vkms_crtc_atomic_disable(struct drm_crtc * crtc,struct drm_atomic_state * state)231 static void vkms_crtc_atomic_disable(struct drm_crtc *crtc,
232 				     struct drm_atomic_state *state)
233 {
234 	drm_crtc_vblank_off(crtc);
235 }
236 
vkms_crtc_atomic_begin(struct drm_crtc * crtc,struct drm_atomic_state * state)237 static void vkms_crtc_atomic_begin(struct drm_crtc *crtc,
238 				   struct drm_atomic_state *state)
239 {
240 	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
241 
242 	/* This lock is held across the atomic commit to block vblank timer
243 	 * from scheduling vkms_composer_worker until the composer is updated
244 	 */
245 	spin_lock_irq(&vkms_output->lock);
246 }
247 
vkms_crtc_atomic_flush(struct drm_crtc * crtc,struct drm_atomic_state * state)248 static void vkms_crtc_atomic_flush(struct drm_crtc *crtc,
249 				   struct drm_atomic_state *state)
250 {
251 	struct vkms_output *vkms_output = drm_crtc_to_vkms_output(crtc);
252 
253 	if (crtc->state->event) {
254 		spin_lock(&crtc->dev->event_lock);
255 
256 		if (drm_crtc_vblank_get(crtc) != 0)
257 			drm_crtc_send_vblank_event(crtc, crtc->state->event);
258 		else
259 			drm_crtc_arm_vblank_event(crtc, crtc->state->event);
260 
261 		spin_unlock(&crtc->dev->event_lock);
262 
263 		crtc->state->event = NULL;
264 	}
265 
266 	vkms_output->composer_state = to_vkms_crtc_state(crtc->state);
267 
268 	spin_unlock_irq(&vkms_output->lock);
269 }
270 
271 static const struct drm_crtc_helper_funcs vkms_crtc_helper_funcs = {
272 	.atomic_check	= vkms_crtc_atomic_check,
273 	.atomic_begin	= vkms_crtc_atomic_begin,
274 	.atomic_flush	= vkms_crtc_atomic_flush,
275 	.atomic_enable	= vkms_crtc_atomic_enable,
276 	.atomic_disable	= vkms_crtc_atomic_disable,
277 };
278 
vkms_crtc_init(struct drm_device * dev,struct drm_crtc * crtc,struct drm_plane * primary,struct drm_plane * cursor)279 int vkms_crtc_init(struct drm_device *dev, struct drm_crtc *crtc,
280 		   struct drm_plane *primary, struct drm_plane *cursor)
281 {
282 	struct vkms_output *vkms_out = drm_crtc_to_vkms_output(crtc);
283 	int ret;
284 
285 	ret = drm_crtc_init_with_planes(dev, crtc, primary, cursor,
286 					&vkms_crtc_funcs, NULL);
287 	if (ret) {
288 		DRM_ERROR("Failed to init CRTC\n");
289 		return ret;
290 	}
291 
292 	drm_crtc_helper_add(crtc, &vkms_crtc_helper_funcs);
293 
294 	spin_lock_init(&vkms_out->lock);
295 	spin_lock_init(&vkms_out->composer_lock);
296 
297 	vkms_out->composer_workq = alloc_ordered_workqueue("vkms_composer", 0);
298 	if (!vkms_out->composer_workq)
299 		return -ENOMEM;
300 
301 	return ret;
302 }
303