1/**
   2 * \file drm_irq.c
   3 * IRQ support
   4 *
   5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
   6 * \author Gareth Hughes <gareth@valinux.com>
   7 */
   8
   9/*
  10 * Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
  11 *
  12 * Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
  13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
  14 * All Rights Reserved.
  15 *
  16 * Permission is hereby granted, free of charge, to any person obtaining a
  17 * copy of this software and associated documentation files (the "Software"),
  18 * to deal in the Software without restriction, including without limitation
  19 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  20 * and/or sell copies of the Software, and to permit persons to whom the
  21 * Software is furnished to do so, subject to the following conditions:
  22 *
  23 * The above copyright notice and this permission notice (including the next
  24 * paragraph) shall be included in all copies or substantial portions of the
  25 * Software.
  26 *
  27 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  28 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  29 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  30 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  31 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  32 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  33 * OTHER DEALINGS IN THE SOFTWARE.
  34 */
  35
  36#include "drmP.h"
  37#include "drm_trace.h"
  38
  39#include <linux/interrupt.h>	/* For task queue support */
  40#include <linux/slab.h>
  41
  42#include <linux/vgaarb.h>
 
  43
  44/* Access macro for slots in vblank timestamp ringbuffer. */
  45#define vblanktimestamp(dev, crtc, count) ( \
  46	(dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \
  47	((count) % DRM_VBLANKTIME_RBSIZE)])
  48
  49/* Retry timestamp calculation up to 3 times to satisfy
  50 * drm_timestamp_precision before giving up.
  51 */
  52#define DRM_TIMESTAMP_MAXRETRIES 3
  53
  54/* Threshold in nanoseconds for detection of redundant
  55 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
  56 */
  57#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
  58
  59/**
  60 * Get interrupt from bus id.
  61 *
  62 * \param inode device inode.
  63 * \param file_priv DRM file private.
  64 * \param cmd command.
  65 * \param arg user argument, pointing to a drm_irq_busid structure.
  66 * \return zero on success or a negative number on failure.
  67 *
  68 * Finds the PCI device with the specified bus id and gets its IRQ number.
  69 * This IOCTL is deprecated, and will now return EINVAL for any busid not equal
  70 * to that of the device that this DRM instance attached to.
  71 */
  72int drm_irq_by_busid(struct drm_device *dev, void *data,
  73		     struct drm_file *file_priv)
  74{
  75	struct drm_irq_busid *p = data;
  76
  77	if (!dev->driver->bus->irq_by_busid)
  78		return -EINVAL;
  79
  80	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
  81		return -EINVAL;
  82
  83	return dev->driver->bus->irq_by_busid(dev, p);
  84}
  85
  86/*
  87 * Clear vblank timestamp buffer for a crtc.
  88 */
  89static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
  90{
  91	memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0,
  92		DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval));
  93}
  94
  95/*
  96 * Disable vblank irq's on crtc, make sure that last vblank count
  97 * of hardware and corresponding consistent software vblank counter
  98 * are preserved, even if there are any spurious vblank irq's after
  99 * disable.
 100 */
 101static void vblank_disable_and_save(struct drm_device *dev, int crtc)
 102{
 103	unsigned long irqflags;
 104	u32 vblcount;
 105	s64 diff_ns;
 106	int vblrc;
 107	struct timeval tvblank;
 108
 109	/* Prevent vblank irq processing while disabling vblank irqs,
 110	 * so no updates of timestamps or count can happen after we've
 111	 * disabled. Needed to prevent races in case of delayed irq's.
 112	 * Disable preemption, so vblank_time_lock is held as short as
 113	 * possible, even under a kernel with PREEMPT_RT patches.
 114	 */
 115	preempt_disable();
 116	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
 117
 118	dev->driver->disable_vblank(dev, crtc);
 119	dev->vblank_enabled[crtc] = 0;
 120
 121	/* No further vblank irq's will be processed after
 122	 * this point. Get current hardware vblank count and
 123	 * vblank timestamp, repeat until they are consistent.
 124	 *
 125	 * FIXME: There is still a race condition here and in
 126	 * drm_update_vblank_count() which can cause off-by-one
 127	 * reinitialization of software vblank counter. If gpu
 128	 * vblank counter doesn't increment exactly at the leading
 129	 * edge of a vblank interval, then we can lose 1 count if
 130	 * we happen to execute between start of vblank and the
 131	 * delayed gpu counter increment.
 132	 */
 133	do {
 134		dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc);
 135		vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
 136	} while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc));
 137
 138	/* Compute time difference to stored timestamp of last vblank
 139	 * as updated by last invocation of drm_handle_vblank() in vblank irq.
 140	 */
 141	vblcount = atomic_read(&dev->_vblank_count[crtc]);
 142	diff_ns = timeval_to_ns(&tvblank) -
 143		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
 144
 145	/* If there is at least 1 msec difference between the last stored
 146	 * timestamp and tvblank, then we are currently executing our
 147	 * disable inside a new vblank interval, the tvblank timestamp
 148	 * corresponds to this new vblank interval and the irq handler
 149	 * for this vblank didn't run yet and won't run due to our disable.
 150	 * Therefore we need to do the job of drm_handle_vblank() and
 151	 * increment the vblank counter by one to account for this vblank.
 152	 *
 153	 * Skip this step if there isn't any high precision timestamp
 154	 * available. In that case we can't account for this and just
 155	 * hope for the best.
 156	 */
 157	if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
 158		atomic_inc(&dev->_vblank_count[crtc]);
 159		smp_mb__after_atomic_inc();
 160	}
 161
 162	/* Invalidate all timestamps while vblank irq's are off. */
 163	clear_vblank_timestamps(dev, crtc);
 164
 165	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
 166	preempt_enable();
 167}
 168
 169static void vblank_disable_fn(unsigned long arg)
 170{
 171	struct drm_device *dev = (struct drm_device *)arg;
 172	unsigned long irqflags;
 173	int i;
 174
 175	if (!dev->vblank_disable_allowed)
 176		return;
 177
 178	for (i = 0; i < dev->num_crtcs; i++) {
 179		spin_lock_irqsave(&dev->vbl_lock, irqflags);
 180		if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
 181		    dev->vblank_enabled[i]) {
 182			DRM_DEBUG("disabling vblank on crtc %d\n", i);
 183			vblank_disable_and_save(dev, i);
 184		}
 185		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 186	}
 187}
 188
 189void drm_vblank_cleanup(struct drm_device *dev)
 190{
 191	/* Bail if the driver didn't call drm_vblank_init() */
 192	if (dev->num_crtcs == 0)
 193		return;
 194
 195	del_timer(&dev->vblank_disable_timer);
 196
 197	vblank_disable_fn((unsigned long)dev);
 198
 199	kfree(dev->vbl_queue);
 200	kfree(dev->_vblank_count);
 201	kfree(dev->vblank_refcount);
 202	kfree(dev->vblank_enabled);
 203	kfree(dev->last_vblank);
 204	kfree(dev->last_vblank_wait);
 205	kfree(dev->vblank_inmodeset);
 206	kfree(dev->_vblank_time);
 207
 208	dev->num_crtcs = 0;
 209}
 210EXPORT_SYMBOL(drm_vblank_cleanup);
 211
 212int drm_vblank_init(struct drm_device *dev, int num_crtcs)
 213{
 214	int i, ret = -ENOMEM;
 215
 216	setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
 217		    (unsigned long)dev);
 218	spin_lock_init(&dev->vbl_lock);
 219	spin_lock_init(&dev->vblank_time_lock);
 220
 221	dev->num_crtcs = num_crtcs;
 222
 223	dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs,
 224				 GFP_KERNEL);
 225	if (!dev->vbl_queue)
 226		goto err;
 227
 228	dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL);
 229	if (!dev->_vblank_count)
 230		goto err;
 231
 232	dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs,
 233				       GFP_KERNEL);
 234	if (!dev->vblank_refcount)
 235		goto err;
 236
 237	dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
 238	if (!dev->vblank_enabled)
 239		goto err;
 240
 241	dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
 242	if (!dev->last_vblank)
 243		goto err;
 244
 245	dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
 246	if (!dev->last_vblank_wait)
 247		goto err;
 248
 249	dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
 250	if (!dev->vblank_inmodeset)
 251		goto err;
 252
 253	dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE,
 254				    sizeof(struct timeval), GFP_KERNEL);
 255	if (!dev->_vblank_time)
 256		goto err;
 257
 258	DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n");
 259
 260	/* Driver specific high-precision vblank timestamping supported? */
 261	if (dev->driver->get_vblank_timestamp)
 262		DRM_INFO("Driver supports precise vblank timestamp query.\n");
 263	else
 264		DRM_INFO("No driver support for vblank timestamp query.\n");
 265
 266	/* Zero per-crtc vblank stuff */
 267	for (i = 0; i < num_crtcs; i++) {
 268		init_waitqueue_head(&dev->vbl_queue[i]);
 269		atomic_set(&dev->_vblank_count[i], 0);
 270		atomic_set(&dev->vblank_refcount[i], 0);
 271	}
 272
 273	dev->vblank_disable_allowed = 0;
 274	return 0;
 275
 276err:
 277	drm_vblank_cleanup(dev);
 278	return ret;
 279}
 280EXPORT_SYMBOL(drm_vblank_init);
 281
 282static void drm_irq_vgaarb_nokms(void *cookie, bool state)
 283{
 284	struct drm_device *dev = cookie;
 285
 286	if (dev->driver->vgaarb_irq) {
 287		dev->driver->vgaarb_irq(dev, state);
 288		return;
 289	}
 290
 291	if (!dev->irq_enabled)
 292		return;
 293
 294	if (state) {
 295		if (dev->driver->irq_uninstall)
 296			dev->driver->irq_uninstall(dev);
 297	} else {
 298		if (dev->driver->irq_preinstall)
 299			dev->driver->irq_preinstall(dev);
 300		if (dev->driver->irq_postinstall)
 301			dev->driver->irq_postinstall(dev);
 302	}
 303}
 304
 305/**
 306 * Install IRQ handler.
 307 *
 308 * \param dev DRM device.
 309 *
 310 * Initializes the IRQ related data. Installs the handler, calling the driver
 311 * \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
 312 * before and after the installation.
 313 */
 314int drm_irq_install(struct drm_device *dev)
 315{
 316	int ret = 0;
 317	unsigned long sh_flags = 0;
 318	char *irqname;
 319
 320	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 321		return -EINVAL;
 322
 323	if (drm_dev_to_irq(dev) == 0)
 324		return -EINVAL;
 325
 326	mutex_lock(&dev->struct_mutex);
 327
 328	/* Driver must have been initialized */
 329	if (!dev->dev_private) {
 330		mutex_unlock(&dev->struct_mutex);
 331		return -EINVAL;
 332	}
 333
 334	if (dev->irq_enabled) {
 335		mutex_unlock(&dev->struct_mutex);
 336		return -EBUSY;
 337	}
 338	dev->irq_enabled = 1;
 339	mutex_unlock(&dev->struct_mutex);
 340
 341	DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
 342
 343	/* Before installing handler */
 344	if (dev->driver->irq_preinstall)
 345		dev->driver->irq_preinstall(dev);
 346
 347	/* Install handler */
 348	if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
 349		sh_flags = IRQF_SHARED;
 350
 351	if (dev->devname)
 352		irqname = dev->devname;
 353	else
 354		irqname = dev->driver->name;
 355
 356	ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
 357			  sh_flags, irqname, dev);
 358
 359	if (ret < 0) {
 360		mutex_lock(&dev->struct_mutex);
 361		dev->irq_enabled = 0;
 362		mutex_unlock(&dev->struct_mutex);
 363		return ret;
 364	}
 365
 366	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 367		vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
 368
 369	/* After installing handler */
 370	if (dev->driver->irq_postinstall)
 371		ret = dev->driver->irq_postinstall(dev);
 372
 373	if (ret < 0) {
 374		mutex_lock(&dev->struct_mutex);
 375		dev->irq_enabled = 0;
 376		mutex_unlock(&dev->struct_mutex);
 377		if (!drm_core_check_feature(dev, DRIVER_MODESET))
 378			vga_client_register(dev->pdev, NULL, NULL, NULL);
 379		free_irq(drm_dev_to_irq(dev), dev);
 380	}
 381
 382	return ret;
 383}
 384EXPORT_SYMBOL(drm_irq_install);
 385
 386/**
 387 * Uninstall the IRQ handler.
 388 *
 389 * \param dev DRM device.
 390 *
 391 * Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
 392 */
 393int drm_irq_uninstall(struct drm_device *dev)
 394{
 395	unsigned long irqflags;
 396	int irq_enabled, i;
 397
 398	if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 399		return -EINVAL;
 400
 401	mutex_lock(&dev->struct_mutex);
 402	irq_enabled = dev->irq_enabled;
 403	dev->irq_enabled = 0;
 404	mutex_unlock(&dev->struct_mutex);
 405
 406	/*
 407	 * Wake up any waiters so they don't hang.
 408	 */
 409	spin_lock_irqsave(&dev->vbl_lock, irqflags);
 410	for (i = 0; i < dev->num_crtcs; i++) {
 411		DRM_WAKEUP(&dev->vbl_queue[i]);
 412		dev->vblank_enabled[i] = 0;
 413		dev->last_vblank[i] = dev->driver->get_vblank_counter(dev, i);
 
 
 
 
 414	}
 415	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 416
 417	if (!irq_enabled)
 418		return -EINVAL;
 419
 420	DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
 421
 422	if (!drm_core_check_feature(dev, DRIVER_MODESET))
 423		vga_client_register(dev->pdev, NULL, NULL, NULL);
 424
 425	if (dev->driver->irq_uninstall)
 426		dev->driver->irq_uninstall(dev);
 427
 428	free_irq(drm_dev_to_irq(dev), dev);
 429
 430	return 0;
 431}
 432EXPORT_SYMBOL(drm_irq_uninstall);
 433
 434/**
 435 * IRQ control ioctl.
 436 *
 437 * \param inode device inode.
 438 * \param file_priv DRM file private.
 439 * \param cmd command.
 440 * \param arg user argument, pointing to a drm_control structure.
 441 * \return zero on success or a negative number on failure.
 442 *
 443 * Calls irq_install() or irq_uninstall() according to \p arg.
 444 */
 445int drm_control(struct drm_device *dev, void *data,
 446		struct drm_file *file_priv)
 447{
 448	struct drm_control *ctl = data;
 449
 450	/* if we haven't irq we fallback for compatibility reasons -
 451	 * this used to be a separate function in drm_dma.h
 452	 */
 453
 454
 455	switch (ctl->func) {
 456	case DRM_INST_HANDLER:
 457		if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 458			return 0;
 459		if (drm_core_check_feature(dev, DRIVER_MODESET))
 460			return 0;
 461		if (dev->if_version < DRM_IF_VERSION(1, 2) &&
 462		    ctl->irq != drm_dev_to_irq(dev))
 463			return -EINVAL;
 464		return drm_irq_install(dev);
 465	case DRM_UNINST_HANDLER:
 466		if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
 467			return 0;
 468		if (drm_core_check_feature(dev, DRIVER_MODESET))
 469			return 0;
 470		return drm_irq_uninstall(dev);
 471	default:
 472		return -EINVAL;
 473	}
 474}
 475
 476/**
 477 * drm_calc_timestamping_constants - Calculate and
 478 * store various constants which are later needed by
 479 * vblank and swap-completion timestamping, e.g, by
 480 * drm_calc_vbltimestamp_from_scanoutpos().
 481 * They are derived from crtc's true scanout timing,
 482 * so they take things like panel scaling or other
 483 * adjustments into account.
 484 *
 485 * @crtc drm_crtc whose timestamp constants should be updated.
 486 *
 487 */
 488void drm_calc_timestamping_constants(struct drm_crtc *crtc)
 489{
 490	s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
 491	u64 dotclock;
 492
 493	/* Dot clock in Hz: */
 494	dotclock = (u64) crtc->hwmode.clock * 1000;
 495
 496	/* Fields of interlaced scanout modes are only halve a frame duration.
 497	 * Double the dotclock to get halve the frame-/line-/pixelduration.
 498	 */
 499	if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE)
 500		dotclock *= 2;
 501
 502	/* Valid dotclock? */
 503	if (dotclock > 0) {
 504		/* Convert scanline length in pixels and video dot clock to
 505		 * line duration, frame duration and pixel duration in
 506		 * nanoseconds:
 507		 */
 508		pixeldur_ns = (s64) div64_u64(1000000000, dotclock);
 509		linedur_ns  = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal *
 510					      1000000000), dotclock);
 511		framedur_ns = (s64) crtc->hwmode.crtc_vtotal * linedur_ns;
 512	} else
 513		DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
 514			  crtc->base.id);
 515
 516	crtc->pixeldur_ns = pixeldur_ns;
 517	crtc->linedur_ns  = linedur_ns;
 518	crtc->framedur_ns = framedur_ns;
 519
 520	DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
 521		  crtc->base.id, crtc->hwmode.crtc_htotal,
 522		  crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay);
 523	DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
 524		  crtc->base.id, (int) dotclock/1000, (int) framedur_ns,
 525		  (int) linedur_ns, (int) pixeldur_ns);
 526}
 527EXPORT_SYMBOL(drm_calc_timestamping_constants);
 528
 529/**
 530 * drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
 531 * drivers. Implements calculation of exact vblank timestamps from
 532 * given drm_display_mode timings and current video scanout position
 533 * of a crtc. This can be called from within get_vblank_timestamp()
 534 * implementation of a kms driver to implement the actual timestamping.
 535 *
 536 * Should return timestamps conforming to the OML_sync_control OpenML
 537 * extension specification. The timestamp corresponds to the end of
 538 * the vblank interval, aka start of scanout of topmost-leftmost display
 539 * pixel in the following video frame.
 540 *
 541 * Requires support for optional dev->driver->get_scanout_position()
 542 * in kms driver, plus a bit of setup code to provide a drm_display_mode
 543 * that corresponds to the true scanout timing.
 544 *
 545 * The current implementation only handles standard video modes. It
 546 * returns as no operation if a doublescan or interlaced video mode is
 547 * active. Higher level code is expected to handle this.
 548 *
 549 * @dev: DRM device.
 550 * @crtc: Which crtc's vblank timestamp to retrieve.
 551 * @max_error: Desired maximum allowable error in timestamps (nanosecs).
 552 *             On return contains true maximum error of timestamp.
 553 * @vblank_time: Pointer to struct timeval which should receive the timestamp.
 554 * @flags: Flags to pass to driver:
 555 *         0 = Default.
 556 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
 557 * @refcrtc: drm_crtc* of crtc which defines scanout timing.
 558 *
 559 * Returns negative value on error, failure or if not supported in current
 560 * video mode:
 561 *
 562 * -EINVAL   - Invalid crtc.
 563 * -EAGAIN   - Temporary unavailable, e.g., called before initial modeset.
 564 * -ENOTSUPP - Function not supported in current display mode.
 565 * -EIO      - Failed, e.g., due to failed scanout position query.
 566 *
 567 * Returns or'ed positive status flags on success:
 568 *
 569 * DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
 570 * DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
 571 *
 572 */
 573int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
 574					  int *max_error,
 575					  struct timeval *vblank_time,
 576					  unsigned flags,
 577					  struct drm_crtc *refcrtc)
 578{
 579	struct timeval stime, raw_time;
 580	struct drm_display_mode *mode;
 581	int vbl_status, vtotal, vdisplay;
 582	int vpos, hpos, i;
 583	s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
 584	bool invbl;
 585
 586	if (crtc < 0 || crtc >= dev->num_crtcs) {
 587		DRM_ERROR("Invalid crtc %d\n", crtc);
 588		return -EINVAL;
 589	}
 590
 591	/* Scanout position query not supported? Should not happen. */
 592	if (!dev->driver->get_scanout_position) {
 593		DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
 594		return -EIO;
 595	}
 596
 597	mode = &refcrtc->hwmode;
 598	vtotal = mode->crtc_vtotal;
 599	vdisplay = mode->crtc_vdisplay;
 600
 601	/* Durations of frames, lines, pixels in nanoseconds. */
 602	framedur_ns = refcrtc->framedur_ns;
 603	linedur_ns  = refcrtc->linedur_ns;
 604	pixeldur_ns = refcrtc->pixeldur_ns;
 605
 606	/* If mode timing undefined, just return as no-op:
 607	 * Happens during initial modesetting of a crtc.
 608	 */
 609	if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) {
 610		DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
 611		return -EAGAIN;
 612	}
 613
 614	/* Get current scanout position with system timestamp.
 615	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
 616	 * if single query takes longer than max_error nanoseconds.
 617	 *
 618	 * This guarantees a tight bound on maximum error if
 619	 * code gets preempted or delayed for some reason.
 620	 */
 621	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
 622		/* Disable preemption to make it very likely to
 623		 * succeed in the first iteration even on PREEMPT_RT kernel.
 624		 */
 625		preempt_disable();
 626
 627		/* Get system timestamp before query. */
 628		do_gettimeofday(&stime);
 629
 630		/* Get vertical and horizontal scanout pos. vpos, hpos. */
 631		vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos);
 632
 633		/* Get system timestamp after query. */
 634		do_gettimeofday(&raw_time);
 635
 636		preempt_enable();
 637
 638		/* Return as no-op if scanout query unsupported or failed. */
 639		if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
 640			DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
 641				  crtc, vbl_status);
 642			return -EIO;
 643		}
 644
 645		duration_ns = timeval_to_ns(&raw_time) - timeval_to_ns(&stime);
 646
 647		/* Accept result with <  max_error nsecs timing uncertainty. */
 648		if (duration_ns <= (s64) *max_error)
 649			break;
 650	}
 651
 652	/* Noisy system timing? */
 653	if (i == DRM_TIMESTAMP_MAXRETRIES) {
 654		DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
 655			  crtc, (int) duration_ns/1000, *max_error/1000, i);
 656	}
 657
 658	/* Return upper bound of timestamp precision error. */
 659	*max_error = (int) duration_ns;
 660
 661	/* Check if in vblank area:
 662	 * vpos is >=0 in video scanout area, but negative
 663	 * within vblank area, counting down the number of lines until
 664	 * start of scanout.
 665	 */
 666	invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
 667
 668	/* Convert scanout position into elapsed time at raw_time query
 669	 * since start of scanout at first display scanline. delta_ns
 670	 * can be negative if start of scanout hasn't happened yet.
 671	 */
 672	delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns;
 673
 674	/* Is vpos outside nominal vblank area, but less than
 675	 * 1/100 of a frame height away from start of vblank?
 676	 * If so, assume this isn't a massively delayed vblank
 677	 * interrupt, but a vblank interrupt that fired a few
 678	 * microseconds before true start of vblank. Compensate
 679	 * by adding a full frame duration to the final timestamp.
 680	 * Happens, e.g., on ATI R500, R600.
 681	 *
 682	 * We only do this if DRM_CALLED_FROM_VBLIRQ.
 683	 */
 684	if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl &&
 685	    ((vdisplay - vpos) < vtotal / 100)) {
 686		delta_ns = delta_ns - framedur_ns;
 687
 688		/* Signal this correction as "applied". */
 689		vbl_status |= 0x8;
 690	}
 691
 692	/* Subtract time delta from raw timestamp to get final
 693	 * vblank_time timestamp for end of vblank.
 694	 */
 695	*vblank_time = ns_to_timeval(timeval_to_ns(&raw_time) - delta_ns);
 696
 697	DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %ld.%ld -> %ld.%ld [e %d us, %d rep]\n",
 698		  crtc, (int)vbl_status, hpos, vpos,
 699		  (long)raw_time.tv_sec, (long)raw_time.tv_usec,
 700		  (long)vblank_time->tv_sec, (long)vblank_time->tv_usec,
 701		  (int)duration_ns/1000, i);
 702
 703	vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
 704	if (invbl)
 705		vbl_status |= DRM_VBLANKTIME_INVBL;
 706
 707	return vbl_status;
 708}
 709EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
 710
 711/**
 712 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
 713 * vblank interval.
 714 *
 715 * @dev: DRM device
 716 * @crtc: which crtc's vblank timestamp to retrieve
 717 * @tvblank: Pointer to target struct timeval which should receive the timestamp
 718 * @flags: Flags to pass to driver:
 719 *         0 = Default.
 720 *         DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
 721 *
 722 * Fetches the system timestamp corresponding to the time of the most recent
 723 * vblank interval on specified crtc. May call into kms-driver to
 724 * compute the timestamp with a high-precision GPU specific method.
 725 *
 726 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
 727 * call, i.e., it isn't very precisely locked to the true vblank.
 728 *
 729 * Returns non-zero if timestamp is considered to be very precise.
 730 */
 731u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
 732			      struct timeval *tvblank, unsigned flags)
 733{
 734	int ret = 0;
 735
 736	/* Define requested maximum error on timestamps (nanoseconds). */
 737	int max_error = (int) drm_timestamp_precision * 1000;
 738
 739	/* Query driver if possible and precision timestamping enabled. */
 740	if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
 741		ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
 742							tvblank, flags);
 743		if (ret > 0)
 744			return (u32) ret;
 745	}
 746
 747	/* GPU high precision timestamp query unsupported or failed.
 748	 * Return gettimeofday timestamp as best estimate.
 749	 */
 750	do_gettimeofday(tvblank);
 751
 752	return 0;
 753}
 754EXPORT_SYMBOL(drm_get_last_vbltimestamp);
 755
 756/**
 757 * drm_vblank_count - retrieve "cooked" vblank counter value
 758 * @dev: DRM device
 759 * @crtc: which counter to retrieve
 760 *
 761 * Fetches the "cooked" vblank count value that represents the number of
 762 * vblank events since the system was booted, including lost events due to
 763 * modesetting activity.
 764 */
 765u32 drm_vblank_count(struct drm_device *dev, int crtc)
 766{
 767	return atomic_read(&dev->_vblank_count[crtc]);
 768}
 769EXPORT_SYMBOL(drm_vblank_count);
 770
 771/**
 772 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value
 773 * and the system timestamp corresponding to that vblank counter value.
 774 *
 775 * @dev: DRM device
 776 * @crtc: which counter to retrieve
 777 * @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
 778 *
 779 * Fetches the "cooked" vblank count value that represents the number of
 780 * vblank events since the system was booted, including lost events due to
 781 * modesetting activity. Returns corresponding system timestamp of the time
 782 * of the vblank interval that corresponds to the current value vblank counter
 783 * value.
 784 */
 785u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
 786			      struct timeval *vblanktime)
 787{
 788	u32 cur_vblank;
 789
 790	/* Read timestamp from slot of _vblank_time ringbuffer
 791	 * that corresponds to current vblank count. Retry if
 792	 * count has incremented during readout. This works like
 793	 * a seqlock.
 794	 */
 795	do {
 796		cur_vblank = atomic_read(&dev->_vblank_count[crtc]);
 797		*vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
 798		smp_rmb();
 799	} while (cur_vblank != atomic_read(&dev->_vblank_count[crtc]));
 800
 801	return cur_vblank;
 802}
 803EXPORT_SYMBOL(drm_vblank_count_and_time);
 804
 805/**
 806 * drm_update_vblank_count - update the master vblank counter
 807 * @dev: DRM device
 808 * @crtc: counter to update
 809 *
 810 * Call back into the driver to update the appropriate vblank counter
 811 * (specified by @crtc).  Deal with wraparound, if it occurred, and
 812 * update the last read value so we can deal with wraparound on the next
 813 * call if necessary.
 814 *
 815 * Only necessary when going from off->on, to account for frames we
 816 * didn't get an interrupt for.
 817 *
 818 * Note: caller must hold dev->vbl_lock since this reads & writes
 819 * device vblank fields.
 820 */
 821static void drm_update_vblank_count(struct drm_device *dev, int crtc)
 822{
 823	u32 cur_vblank, diff, tslot, rc;
 824	struct timeval t_vblank;
 825
 826	/*
 827	 * Interrupts were disabled prior to this call, so deal with counter
 828	 * wrap if needed.
 829	 * NOTE!  It's possible we lost a full dev->max_vblank_count events
 830	 * here if the register is small or we had vblank interrupts off for
 831	 * a long time.
 832	 *
 833	 * We repeat the hardware vblank counter & timestamp query until
 834	 * we get consistent results. This to prevent races between gpu
 835	 * updating its hardware counter while we are retrieving the
 836	 * corresponding vblank timestamp.
 837	 */
 838	do {
 839		cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
 840		rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
 841	} while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
 842
 843	/* Deal with counter wrap */
 844	diff = cur_vblank - dev->last_vblank[crtc];
 845	if (cur_vblank < dev->last_vblank[crtc]) {
 846		diff += dev->max_vblank_count;
 847
 848		DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
 849			  crtc, dev->last_vblank[crtc], cur_vblank, diff);
 850	}
 851
 852	DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
 853		  crtc, diff);
 854
 855	/* Reinitialize corresponding vblank timestamp if high-precision query
 856	 * available. Skip this step if query unsupported or failed. Will
 857	 * reinitialize delayed at next vblank interrupt in that case.
 858	 */
 859	if (rc) {
 860		tslot = atomic_read(&dev->_vblank_count[crtc]) + diff;
 861		vblanktimestamp(dev, crtc, tslot) = t_vblank;
 862	}
 863
 864	smp_mb__before_atomic_inc();
 865	atomic_add(diff, &dev->_vblank_count[crtc]);
 866	smp_mb__after_atomic_inc();
 867}
 868
 869/**
 870 * drm_vblank_get - get a reference count on vblank events
 871 * @dev: DRM device
 872 * @crtc: which CRTC to own
 873 *
 874 * Acquire a reference count on vblank events to avoid having them disabled
 875 * while in use.
 876 *
 877 * RETURNS
 878 * Zero on success, nonzero on failure.
 879 */
 880int drm_vblank_get(struct drm_device *dev, int crtc)
 881{
 882	unsigned long irqflags, irqflags2;
 883	int ret = 0;
 884
 885	spin_lock_irqsave(&dev->vbl_lock, irqflags);
 886	/* Going from 0->1 means we have to enable interrupts again */
 887	if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) {
 888		/* Disable preemption while holding vblank_time_lock. Do
 889		 * it explicitely to guard against PREEMPT_RT kernel.
 890		 */
 891		preempt_disable();
 892		spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
 893		if (!dev->vblank_enabled[crtc]) {
 894			/* Enable vblank irqs under vblank_time_lock protection.
 895			 * All vblank count & timestamp updates are held off
 896			 * until we are done reinitializing master counter and
 897			 * timestamps. Filtercode in drm_handle_vblank() will
 898			 * prevent double-accounting of same vblank interval.
 899			 */
 900			ret = dev->driver->enable_vblank(dev, crtc);
 901			DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
 902				  crtc, ret);
 903			if (ret)
 904				atomic_dec(&dev->vblank_refcount[crtc]);
 905			else {
 906				dev->vblank_enabled[crtc] = 1;
 907				drm_update_vblank_count(dev, crtc);
 908			}
 909		}
 910		spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
 911		preempt_enable();
 912	} else {
 913		if (!dev->vblank_enabled[crtc]) {
 914			atomic_dec(&dev->vblank_refcount[crtc]);
 915			ret = -EINVAL;
 916		}
 917	}
 918	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 919
 920	return ret;
 921}
 922EXPORT_SYMBOL(drm_vblank_get);
 923
 924/**
 925 * drm_vblank_put - give up ownership of vblank events
 926 * @dev: DRM device
 927 * @crtc: which counter to give up
 928 *
 929 * Release ownership of a given vblank counter, turning off interrupts
 930 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
 931 */
 932void drm_vblank_put(struct drm_device *dev, int crtc)
 933{
 934	BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0);
 935
 936	/* Last user schedules interrupt disable */
 937	if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) &&
 938	    (drm_vblank_offdelay > 0))
 939		mod_timer(&dev->vblank_disable_timer,
 940			  jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000));
 941}
 942EXPORT_SYMBOL(drm_vblank_put);
 943
 944void drm_vblank_off(struct drm_device *dev, int crtc)
 945{
 946	struct drm_pending_vblank_event *e, *t;
 947	struct timeval now;
 948	unsigned long irqflags;
 949	unsigned int seq;
 950
 951	spin_lock_irqsave(&dev->vbl_lock, irqflags);
 952	vblank_disable_and_save(dev, crtc);
 953	DRM_WAKEUP(&dev->vbl_queue[crtc]);
 954
 955	/* Send any queued vblank events, lest the natives grow disquiet */
 956	seq = drm_vblank_count_and_time(dev, crtc, &now);
 957	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
 958		if (e->pipe != crtc)
 959			continue;
 960		DRM_DEBUG("Sending premature vblank event on disable: \
 961			  wanted %d, current %d\n",
 962			  e->event.sequence, seq);
 963
 964		e->event.sequence = seq;
 965		e->event.tv_sec = now.tv_sec;
 966		e->event.tv_usec = now.tv_usec;
 967		drm_vblank_put(dev, e->pipe);
 968		list_move_tail(&e->base.link, &e->base.file_priv->event_list);
 969		wake_up_interruptible(&e->base.file_priv->event_wait);
 970		trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
 971						 e->event.sequence);
 972	}
 973
 974	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 975}
 976EXPORT_SYMBOL(drm_vblank_off);
 977
 978/**
 979 * drm_vblank_pre_modeset - account for vblanks across mode sets
 980 * @dev: DRM device
 981 * @crtc: CRTC in question
 982 * @post: post or pre mode set?
 983 *
 984 * Account for vblank events across mode setting events, which will likely
 985 * reset the hardware frame counter.
 986 */
 987void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
 988{
 989	/* vblank is not initialized (IRQ not installed ?) */
 990	if (!dev->num_crtcs)
 991		return;
 992	/*
 993	 * To avoid all the problems that might happen if interrupts
 994	 * were enabled/disabled around or between these calls, we just
 995	 * have the kernel take a reference on the CRTC (just once though
 996	 * to avoid corrupting the count if multiple, mismatch calls occur),
 997	 * so that interrupts remain enabled in the interim.
 998	 */
 999	if (!dev->vblank_inmodeset[crtc]) {
1000		dev->vblank_inmodeset[crtc] = 0x1;
1001		if (drm_vblank_get(dev, crtc) == 0)
1002			dev->vblank_inmodeset[crtc] |= 0x2;
1003	}
1004}
1005EXPORT_SYMBOL(drm_vblank_pre_modeset);
1006
1007void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
1008{
1009	unsigned long irqflags;
1010
1011	if (dev->vblank_inmodeset[crtc]) {
1012		spin_lock_irqsave(&dev->vbl_lock, irqflags);
1013		dev->vblank_disable_allowed = 1;
1014		spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1015
1016		if (dev->vblank_inmodeset[crtc] & 0x2)
1017			drm_vblank_put(dev, crtc);
1018
1019		dev->vblank_inmodeset[crtc] = 0;
1020	}
1021}
1022EXPORT_SYMBOL(drm_vblank_post_modeset);
1023
1024/**
1025 * drm_modeset_ctl - handle vblank event counter changes across mode switch
1026 * @DRM_IOCTL_ARGS: standard ioctl arguments
1027 *
1028 * Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
1029 * ioctls around modesetting so that any lost vblank events are accounted for.
1030 *
1031 * Generally the counter will reset across mode sets.  If interrupts are
1032 * enabled around this call, we don't have to do anything since the counter
1033 * will have already been incremented.
1034 */
1035int drm_modeset_ctl(struct drm_device *dev, void *data,
1036		    struct drm_file *file_priv)
1037{
1038	struct drm_modeset_ctl *modeset = data;
1039	int ret = 0;
1040	unsigned int crtc;
1041
1042	/* If drm_vblank_init() hasn't been called yet, just no-op */
1043	if (!dev->num_crtcs)
1044		goto out;
1045
1046	crtc = modeset->crtc;
1047	if (crtc >= dev->num_crtcs) {
1048		ret = -EINVAL;
1049		goto out;
1050	}
1051
1052	switch (modeset->cmd) {
1053	case _DRM_PRE_MODESET:
1054		drm_vblank_pre_modeset(dev, crtc);
1055		break;
1056	case _DRM_POST_MODESET:
1057		drm_vblank_post_modeset(dev, crtc);
1058		break;
1059	default:
1060		ret = -EINVAL;
1061		break;
1062	}
1063
1064out:
1065	return ret;
1066}
1067
1068static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
1069				  union drm_wait_vblank *vblwait,
1070				  struct drm_file *file_priv)
1071{
1072	struct drm_pending_vblank_event *e;
1073	struct timeval now;
1074	unsigned long flags;
1075	unsigned int seq;
1076	int ret;
1077
1078	e = kzalloc(sizeof *e, GFP_KERNEL);
1079	if (e == NULL) {
1080		ret = -ENOMEM;
1081		goto err_put;
1082	}
1083
1084	e->pipe = pipe;
1085	e->base.pid = current->pid;
1086	e->event.base.type = DRM_EVENT_VBLANK;
1087	e->event.base.length = sizeof e->event;
1088	e->event.user_data = vblwait->request.signal;
1089	e->base.event = &e->event.base;
1090	e->base.file_priv = file_priv;
1091	e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
1092
1093	spin_lock_irqsave(&dev->event_lock, flags);
1094
1095	if (file_priv->event_space < sizeof e->event) {
1096		ret = -EBUSY;
1097		goto err_unlock;
1098	}
1099
1100	file_priv->event_space -= sizeof e->event;
1101	seq = drm_vblank_count_and_time(dev, pipe, &now);
1102
1103	if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
1104	    (seq - vblwait->request.sequence) <= (1 << 23)) {
1105		vblwait->request.sequence = seq + 1;
1106		vblwait->reply.sequence = vblwait->request.sequence;
1107	}
1108
1109	DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
1110		  vblwait->request.sequence, seq, pipe);
1111
1112	trace_drm_vblank_event_queued(current->pid, pipe,
1113				      vblwait->request.sequence);
1114
1115	e->event.sequence = vblwait->request.sequence;
1116	if ((seq - vblwait->request.sequence) <= (1 << 23)) {
1117		e->event.sequence = seq;
1118		e->event.tv_sec = now.tv_sec;
1119		e->event.tv_usec = now.tv_usec;
1120		drm_vblank_put(dev, pipe);
1121		list_add_tail(&e->base.link, &e->base.file_priv->event_list);
1122		wake_up_interruptible(&e->base.file_priv->event_wait);
1123		vblwait->reply.sequence = seq;
1124		trace_drm_vblank_event_delivered(current->pid, pipe,
1125						 vblwait->request.sequence);
1126	} else {
 
1127		list_add_tail(&e->base.link, &dev->vblank_event_list);
1128		vblwait->reply.sequence = vblwait->request.sequence;
1129	}
1130
1131	spin_unlock_irqrestore(&dev->event_lock, flags);
1132
1133	return 0;
1134
1135err_unlock:
1136	spin_unlock_irqrestore(&dev->event_lock, flags);
1137	kfree(e);
1138err_put:
1139	drm_vblank_put(dev, pipe);
1140	return ret;
1141}
1142
1143/**
1144 * Wait for VBLANK.
1145 *
1146 * \param inode device inode.
1147 * \param file_priv DRM file private.
1148 * \param cmd command.
1149 * \param data user argument, pointing to a drm_wait_vblank structure.
1150 * \return zero on success or a negative number on failure.
1151 *
1152 * This function enables the vblank interrupt on the pipe requested, then
1153 * sleeps waiting for the requested sequence number to occur, and drops
1154 * the vblank interrupt refcount afterwards. (vblank irq disable follows that
1155 * after a timeout with no further vblank waits scheduled).
1156 */
1157int drm_wait_vblank(struct drm_device *dev, void *data,
1158		    struct drm_file *file_priv)
1159{
1160	union drm_wait_vblank *vblwait = data;
1161	int ret = 0;
1162	unsigned int flags, seq, crtc, high_crtc;
1163
1164	if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
1165		return -EINVAL;
1166
1167	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1168		return -EINVAL;
1169
1170	if (vblwait->request.type &
1171	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1172	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
1173		DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
1174			  vblwait->request.type,
1175			  (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1176			   _DRM_VBLANK_HIGH_CRTC_MASK));
1177		return -EINVAL;
1178	}
1179
1180	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1181	high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1182	if (high_crtc)
1183		crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1184	else
1185		crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1186	if (crtc >= dev->num_crtcs)
1187		return -EINVAL;
1188
1189	ret = drm_vblank_get(dev, crtc);
1190	if (ret) {
1191		DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
1192		return ret;
1193	}
1194	seq = drm_vblank_count(dev, crtc);
1195
1196	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1197	case _DRM_VBLANK_RELATIVE:
1198		vblwait->request.sequence += seq;
1199		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1200	case _DRM_VBLANK_ABSOLUTE:
1201		break;
1202	default:
1203		ret = -EINVAL;
1204		goto done;
1205	}
1206
1207	if (flags & _DRM_VBLANK_EVENT)
 
 
 
1208		return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
 
1209
1210	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1211	    (seq - vblwait->request.sequence) <= (1<<23)) {
1212		vblwait->request.sequence = seq + 1;
1213	}
1214
1215	DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
1216		  vblwait->request.sequence, crtc);
1217	dev->last_vblank_wait[crtc] = vblwait->request.sequence;
1218	DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
1219		    (((drm_vblank_count(dev, crtc) -
1220		       vblwait->request.sequence) <= (1 << 23)) ||
1221		     !dev->irq_enabled));
1222
1223	if (ret != -EINTR) {
1224		struct timeval now;
1225
1226		vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
1227		vblwait->reply.tval_sec = now.tv_sec;
1228		vblwait->reply.tval_usec = now.tv_usec;
1229
1230		DRM_DEBUG("returning %d to client\n",
1231			  vblwait->reply.sequence);
1232	} else {
1233		DRM_DEBUG("vblank wait interrupted by signal\n");
1234	}
1235
1236done:
1237	drm_vblank_put(dev, crtc);
1238	return ret;
1239}
1240
1241void drm_handle_vblank_events(struct drm_device *dev, int crtc)
1242{
1243	struct drm_pending_vblank_event *e, *t;
1244	struct timeval now;
1245	unsigned long flags;
1246	unsigned int seq;
1247
1248	seq = drm_vblank_count_and_time(dev, crtc, &now);
1249
1250	spin_lock_irqsave(&dev->event_lock, flags);
1251
1252	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1253		if (e->pipe != crtc)
1254			continue;
1255		if ((seq - e->event.sequence) > (1<<23))
1256			continue;
1257
1258		DRM_DEBUG("vblank event on %d, current %d\n",
1259			  e->event.sequence, seq);
1260
1261		e->event.sequence = seq;
1262		e->event.tv_sec = now.tv_sec;
1263		e->event.tv_usec = now.tv_usec;
1264		drm_vblank_put(dev, e->pipe);
1265		list_move_tail(&e->base.link, &e->base.file_priv->event_list);
1266		wake_up_interruptible(&e->base.file_priv->event_wait);
1267		trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
1268						 e->event.sequence);
1269	}
1270
1271	spin_unlock_irqrestore(&dev->event_lock, flags);
1272
1273	trace_drm_vblank_event(crtc, seq);
1274}
1275
1276/**
1277 * drm_handle_vblank - handle a vblank event
1278 * @dev: DRM device
1279 * @crtc: where this event occurred
1280 *
1281 * Drivers should call this routine in their vblank interrupt handlers to
1282 * update the vblank counter and send any signals that may be pending.
1283 */
1284bool drm_handle_vblank(struct drm_device *dev, int crtc)
1285{
1286	u32 vblcount;
1287	s64 diff_ns;
1288	struct timeval tvblank;
1289	unsigned long irqflags;
1290
1291	if (!dev->num_crtcs)
1292		return false;
1293
1294	/* Need timestamp lock to prevent concurrent execution with
1295	 * vblank enable/disable, as this would cause inconsistent
1296	 * or corrupted timestamps and vblank counts.
1297	 */
1298	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
1299
1300	/* Vblank irq handling disabled. Nothing to do. */
1301	if (!dev->vblank_enabled[crtc]) {
1302		spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1303		return false;
1304	}
1305
1306	/* Fetch corresponding timestamp for this vblank interval from
1307	 * driver and store it in proper slot of timestamp ringbuffer.
1308	 */
1309
1310	/* Get current timestamp and count. */
1311	vblcount = atomic_read(&dev->_vblank_count[crtc]);
1312	drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
1313
1314	/* Compute time difference to timestamp of last vblank */
1315	diff_ns = timeval_to_ns(&tvblank) -
1316		  timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
1317
1318	/* Update vblank timestamp and count if at least
1319	 * DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
1320	 * difference between last stored timestamp and current
1321	 * timestamp. A smaller difference means basically
1322	 * identical timestamps. Happens if this vblank has
1323	 * been already processed and this is a redundant call,
1324	 * e.g., due to spurious vblank interrupts. We need to
1325	 * ignore those for accounting.
1326	 */
1327	if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
1328		/* Store new timestamp in ringbuffer. */
1329		vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
1330
1331		/* Increment cooked vblank count. This also atomically commits
1332		 * the timestamp computed above.
1333		 */
1334		smp_mb__before_atomic_inc();
1335		atomic_inc(&dev->_vblank_count[crtc]);
1336		smp_mb__after_atomic_inc();
1337	} else {
1338		DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
1339			  crtc, (int) diff_ns);
1340	}
1341
1342	DRM_WAKEUP(&dev->vbl_queue[crtc]);
1343	drm_handle_vblank_events(dev, crtc);
1344
1345	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
1346	return true;
1347}
1348EXPORT_SYMBOL(drm_handle_vblank);