xen_drm_front_kms.c

  1// SPDX-License-Identifier: GPL-2.0 OR MIT
  2
  3/*
  4 *  Xen para-virtual DRM device
  5 *
  6 * Copyright (C) 2016-2018 EPAM Systems Inc.
  7 *
  8 * Author: Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>
  9 */
 10
 11#include <drm/drm_atomic.h>
 12#include <drm/drm_atomic_helper.h>
 13#include <drm/drm_drv.h>
 14#include <drm/drm_fourcc.h>
 15#include <drm/drm_framebuffer.h>
 16#include <drm/drm_gem.h>
 17#include <drm/drm_gem_atomic_helper.h>
 18#include <drm/drm_gem_framebuffer_helper.h>
 19#include <drm/drm_print.h>
 20#include <drm/drm_probe_helper.h>
 21#include <drm/drm_vblank.h>
 22
 23#include "xen_drm_front.h"
 24#include "xen_drm_front_conn.h"
 25#include "xen_drm_front_kms.h"
 26
 27/*
 28 * Timeout in ms to wait for frame done event from the backend:
 29 * must be a bit more than IO time-out
 30 */
 31#define FRAME_DONE_TO_MS	(XEN_DRM_FRONT_WAIT_BACK_MS + 100)
 32
 33static struct xen_drm_front_drm_pipeline *
 34to_xen_drm_pipeline(struct drm_simple_display_pipe *pipe)
 35{
 36	return container_of(pipe, struct xen_drm_front_drm_pipeline, pipe);
 37}
 38
 39static void fb_destroy(struct drm_framebuffer *fb)
 40{
 41	struct xen_drm_front_drm_info *drm_info = fb->dev->dev_private;
 42	int idx;
 43
 44	if (drm_dev_enter(fb->dev, &idx)) {
 45		xen_drm_front_fb_detach(drm_info->front_info,
 46					xen_drm_front_fb_to_cookie(fb));
 47		drm_dev_exit(idx);
 48	}
 49	drm_gem_fb_destroy(fb);
 50}
 51
 52static const struct drm_framebuffer_funcs fb_funcs = {
 53	.destroy = fb_destroy,
 54};
 55
 56static struct drm_framebuffer *
 57fb_create(struct drm_device *dev, struct drm_file *filp,
 58	  const struct drm_format_info *info,
 59	  const struct drm_mode_fb_cmd2 *mode_cmd)
 60{
 61	struct xen_drm_front_drm_info *drm_info = dev->dev_private;
 62	struct drm_framebuffer *fb;
 63	struct drm_gem_object *gem_obj;
 64	int ret;
 65
 66	fb = drm_gem_fb_create_with_funcs(dev, filp, info, mode_cmd, &fb_funcs);
 67	if (IS_ERR(fb))
 68		return fb;
 69
 70	gem_obj = fb->obj[0];
 71
 72	ret = xen_drm_front_fb_attach(drm_info->front_info,
 73				      xen_drm_front_dbuf_to_cookie(gem_obj),
 74				      xen_drm_front_fb_to_cookie(fb),
 75				      fb->width, fb->height,
 76				      fb->format->format);
 77	if (ret < 0) {
 78		DRM_ERROR("Back failed to attach FB %p: %d\n", fb, ret);
 79		goto fail;
 80	}
 81
 82	return fb;
 83
 84fail:
 85	drm_gem_fb_destroy(fb);
 86	return ERR_PTR(ret);
 87}
 88
 89static const struct drm_mode_config_funcs mode_config_funcs = {
 90	.fb_create = fb_create,
 91	.atomic_check = drm_atomic_helper_check,
 92	.atomic_commit = drm_atomic_helper_commit,
 93};
 94
 95static void send_pending_event(struct xen_drm_front_drm_pipeline *pipeline)
 96{
 97	struct drm_crtc *crtc = &pipeline->pipe.crtc;
 98	struct drm_device *dev = crtc->dev;
 99	unsigned long flags;
100
101	spin_lock_irqsave(&dev->event_lock, flags);
102	if (pipeline->pending_event)
103		drm_crtc_send_vblank_event(crtc, pipeline->pending_event);
104	pipeline->pending_event = NULL;
105	spin_unlock_irqrestore(&dev->event_lock, flags);
106}
107
108static void display_enable(struct drm_simple_display_pipe *pipe,
109			   struct drm_crtc_state *crtc_state,
110			   struct drm_plane_state *plane_state)
111{
112	struct xen_drm_front_drm_pipeline *pipeline =
113			to_xen_drm_pipeline(pipe);
114	struct drm_crtc *crtc = &pipe->crtc;
115	struct drm_framebuffer *fb = plane_state->fb;
116	int ret, idx;
117
118	if (!drm_dev_enter(pipe->crtc.dev, &idx))
119		return;
120
121	ret = xen_drm_front_mode_set(pipeline, crtc->x, crtc->y,
122				     fb->width, fb->height,
123				     fb->format->cpp[0] * 8,
124				     xen_drm_front_fb_to_cookie(fb));
125
126	if (ret) {
127		DRM_ERROR("Failed to enable display: %d\n", ret);
128		pipeline->conn_connected = false;
129	}
130
131	drm_dev_exit(idx);
132}
133
134static void display_disable(struct drm_simple_display_pipe *pipe)
135{
136	struct xen_drm_front_drm_pipeline *pipeline =
137			to_xen_drm_pipeline(pipe);
138	int ret = 0, idx;
139
140	if (drm_dev_enter(pipe->crtc.dev, &idx)) {
141		ret = xen_drm_front_mode_set(pipeline, 0, 0, 0, 0, 0,
142					     xen_drm_front_fb_to_cookie(NULL));
143		drm_dev_exit(idx);
144	}
145	if (ret)
146		DRM_ERROR("Failed to disable display: %d\n", ret);
147
148	/* Make sure we can restart with enabled connector next time */
149	pipeline->conn_connected = true;
150
151	/* release stalled event if any */
152	send_pending_event(pipeline);
153}
154
155void xen_drm_front_kms_on_frame_done(struct xen_drm_front_drm_pipeline *pipeline,
156				     u64 fb_cookie)
157{
158	/*
159	 * This runs in interrupt context, e.g. under
160	 * drm_info->front_info->io_lock, so we cannot call _sync version
161	 * to cancel the work
162	 */
163	cancel_delayed_work(&pipeline->pflip_to_worker);
164
165	send_pending_event(pipeline);
166}
167
168static void pflip_to_worker(struct work_struct *work)
169{
170	struct delayed_work *delayed_work = to_delayed_work(work);
171	struct xen_drm_front_drm_pipeline *pipeline =
172			container_of(delayed_work,
173				     struct xen_drm_front_drm_pipeline,
174				     pflip_to_worker);
175
176	DRM_ERROR("Frame done timed-out, releasing");
177	send_pending_event(pipeline);
178}
179
180static bool display_send_page_flip(struct drm_simple_display_pipe *pipe,
181				   struct drm_plane_state *old_plane_state)
182{
183	struct drm_plane_state *plane_state =
184			drm_atomic_get_new_plane_state(old_plane_state->state,
185						       &pipe->plane);
186
187	/*
188	 * If old_plane_state->fb is NULL and plane_state->fb is not,
189	 * then this is an atomic commit which will enable display.
190	 * If old_plane_state->fb is not NULL and plane_state->fb is,
191	 * then this is an atomic commit which will disable display.
192	 * Ignore these and do not send page flip as this framebuffer will be
193	 * sent to the backend as a part of display_set_config call.
194	 */
195	if (old_plane_state->fb && plane_state->fb) {
196		struct xen_drm_front_drm_pipeline *pipeline =
197				to_xen_drm_pipeline(pipe);
198		struct xen_drm_front_drm_info *drm_info = pipeline->drm_info;
199		int ret;
200
201		schedule_delayed_work(&pipeline->pflip_to_worker,
202				      msecs_to_jiffies(FRAME_DONE_TO_MS));
203
204		ret = xen_drm_front_page_flip(drm_info->front_info,
205					      pipeline->index,
206					      xen_drm_front_fb_to_cookie(plane_state->fb));
207		if (ret) {
208			DRM_ERROR("Failed to send page flip request to backend: %d\n", ret);
209
210			pipeline->conn_connected = false;
211			/*
212			 * Report the flip not handled, so pending event is
213			 * sent, unblocking user-space.
214			 */
215			return false;
216		}
217		/*
218		 * Signal that page flip was handled, pending event will be sent
219		 * on frame done event from the backend.
220		 */
221		return true;
222	}
223
224	return false;
225}
226
227static int display_check(struct drm_simple_display_pipe *pipe,
228			 struct drm_plane_state *plane_state,
229			 struct drm_crtc_state *crtc_state)
230{
231	/*
232	 * Xen doesn't initialize vblanking via drm_vblank_init(), so
233	 * DRM helpers assume that it doesn't handle vblanking and start
234	 * sending out fake VBLANK events automatically.
235	 *
236	 * As xen contains it's own logic for sending out VBLANK events
237	 * in send_pending_event(), disable no_vblank (i.e., the xen
238	 * driver has vblanking support).
239	 */
240	crtc_state->no_vblank = false;
241
242	return 0;
243}
244
245static void display_update(struct drm_simple_display_pipe *pipe,
246			   struct drm_plane_state *old_plane_state)
247{
248	struct xen_drm_front_drm_pipeline *pipeline =
249			to_xen_drm_pipeline(pipe);
250	struct drm_crtc *crtc = &pipe->crtc;
251	struct drm_pending_vblank_event *event;
252	int idx;
253
254	event = crtc->state->event;
255	if (event) {
256		struct drm_device *dev = crtc->dev;
257		unsigned long flags;
258
259		WARN_ON(pipeline->pending_event);
260
261		spin_lock_irqsave(&dev->event_lock, flags);
262		crtc->state->event = NULL;
263
264		pipeline->pending_event = event;
265		spin_unlock_irqrestore(&dev->event_lock, flags);
266	}
267
268	if (!drm_dev_enter(pipe->crtc.dev, &idx)) {
269		send_pending_event(pipeline);
270		return;
271	}
272
273	/*
274	 * Send page flip request to the backend *after* we have event cached
275	 * above, so on page flip done event from the backend we can
276	 * deliver it and there is no race condition between this code and
277	 * event from the backend.
278	 * If this is not a page flip, e.g. no flip done event from the backend
279	 * is expected, then send now.
280	 */
281	if (!display_send_page_flip(pipe, old_plane_state))
282		send_pending_event(pipeline);
283
284	drm_dev_exit(idx);
285}
286
287static enum drm_mode_status
288display_mode_valid(struct drm_simple_display_pipe *pipe,
289		   const struct drm_display_mode *mode)
290{
291	struct xen_drm_front_drm_pipeline *pipeline =
292			container_of(pipe, struct xen_drm_front_drm_pipeline,
293				     pipe);
294
295	if (mode->hdisplay != pipeline->width)
296		return MODE_ERROR;
297
298	if (mode->vdisplay != pipeline->height)
299		return MODE_ERROR;
300
301	return MODE_OK;
302}
303
304static const struct drm_simple_display_pipe_funcs display_funcs = {
305	.mode_valid = display_mode_valid,
306	.enable = display_enable,
307	.disable = display_disable,
308	.check = display_check,
309	.update = display_update,
310};
311
312static int display_pipe_init(struct xen_drm_front_drm_info *drm_info,
313			     int index, struct xen_drm_front_cfg_connector *cfg,
314			     struct xen_drm_front_drm_pipeline *pipeline)
315{
316	struct drm_device *dev = drm_info->drm_dev;
317	const u32 *formats;
318	int format_count;
319	int ret;
320
321	pipeline->drm_info = drm_info;
322	pipeline->index = index;
323	pipeline->height = cfg->height;
324	pipeline->width = cfg->width;
325
326	INIT_DELAYED_WORK(&pipeline->pflip_to_worker, pflip_to_worker);
327
328	ret = xen_drm_front_conn_init(drm_info, &pipeline->conn);
329	if (ret)
330		return ret;
331
332	formats = xen_drm_front_conn_get_formats(&format_count);
333
334	return drm_simple_display_pipe_init(dev, &pipeline->pipe,
335					    &display_funcs, formats,
336					    format_count, NULL,
337					    &pipeline->conn);
338}
339
340int xen_drm_front_kms_init(struct xen_drm_front_drm_info *drm_info)
341{
342	struct drm_device *dev = drm_info->drm_dev;
343	int i, ret;
344
345	drm_mode_config_init(dev);
346
347	dev->mode_config.min_width = 0;
348	dev->mode_config.min_height = 0;
349	dev->mode_config.max_width = 4095;
350	dev->mode_config.max_height = 2047;
351	dev->mode_config.funcs = &mode_config_funcs;
352
353	for (i = 0; i < drm_info->front_info->cfg.num_connectors; i++) {
354		struct xen_drm_front_cfg_connector *cfg =
355				&drm_info->front_info->cfg.connectors[i];
356		struct xen_drm_front_drm_pipeline *pipeline =
357				&drm_info->pipeline[i];
358
359		ret = display_pipe_init(drm_info, i, cfg, pipeline);
360		if (ret) {
361			drm_mode_config_cleanup(dev);
362			return ret;
363		}
364	}
365
366	drm_mode_config_reset(dev);
367	drm_kms_helper_poll_init(dev);
368	return 0;
369}
370
371void xen_drm_front_kms_fini(struct xen_drm_front_drm_info *drm_info)
372{
373	int i;
374
375	for (i = 0; i < drm_info->front_info->cfg.num_connectors; i++) {
376		struct xen_drm_front_drm_pipeline *pipeline =
377				&drm_info->pipeline[i];
378
379		cancel_delayed_work_sync(&pipeline->pflip_to_worker);
380
381		send_pending_event(pipeline);
382	}
383}