1/*
   2 * drm_irq.c IRQ and vblank support
   3 *
   4 * \author Rickard E. (Rik) Faith <faith@valinux.com>
   5 * \author Gareth Hughes <gareth@valinux.com>
   6 *
   7 * Permission is hereby granted, free of charge, to any person obtaining a
   8 * copy of this software and associated documentation files (the "Software"),
   9 * to deal in the Software without restriction, including without limitation
  10 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  11 * and/or sell copies of the Software, and to permit persons to whom the
  12 * Software is furnished to do so, subject to the following conditions:
  13 *
  14 * The above copyright notice and this permission notice (including the next
  15 * paragraph) shall be included in all copies or substantial portions of the
  16 * Software.
  17 *
  18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  21 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  22 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  23 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  24 * OTHER DEALINGS IN THE SOFTWARE.
  25 */
  26
  27#include <linux/export.h>
  28#include <linux/kthread.h>
  29#include <linux/moduleparam.h>
  30
  31#include <drm/drm_crtc.h>
  32#include <drm/drm_drv.h>
  33#include <drm/drm_framebuffer.h>
  34#include <drm/drm_managed.h>
  35#include <drm/drm_modeset_helper_vtables.h>
  36#include <drm/drm_print.h>
  37#include <drm/drm_vblank.h>
  38
  39#include "drm_internal.h"
  40#include "drm_trace.h"
  41
  42/**
  43 * DOC: vblank handling
  44 *
  45 * From the computer's perspective, every time the monitor displays
  46 * a new frame the scanout engine has "scanned out" the display image
  47 * from top to bottom, one row of pixels at a time. The current row
  48 * of pixels is referred to as the current scanline.
  49 *
  50 * In addition to the display's visible area, there's usually a couple of
  51 * extra scanlines which aren't actually displayed on the screen.
  52 * These extra scanlines don't contain image data and are occasionally used
  53 * for features like audio and infoframes. The region made up of these
  54 * scanlines is referred to as the vertical blanking region, or vblank for
  55 * short.
  56 *
  57 * For historical reference, the vertical blanking period was designed to
  58 * give the electron gun (on CRTs) enough time to move back to the top of
  59 * the screen to start scanning out the next frame. Similar for horizontal
  60 * blanking periods. They were designed to give the electron gun enough
  61 * time to move back to the other side of the screen to start scanning the
  62 * next scanline.
  63 *
  64 * ::
  65 *
  66 *
  67 *    physical →   ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽
  68 *    top of      |                                        |
  69 *    display     |                                        |
  70 *                |               New frame                |
  71 *                |                                        |
  72 *                |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓|
  73 *                |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~| ← Scanline,
  74 *                |↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓|   updates the
  75 *                |                                        |   frame as it
  76 *                |                                        |   travels down
  77 *                |                                        |   ("sacn out")
  78 *                |               Old frame                |
  79 *                |                                        |
  80 *                |                                        |
  81 *                |                                        |
  82 *                |                                        |   physical
  83 *                |                                        |   bottom of
  84 *    vertical    |⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽| ← display
  85 *    blanking    ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
  86 *    region   →  ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
  87 *                ┆xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx┆
  88 *    start of →   ⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽⎽
  89 *    new frame
  90 *
  91 * "Physical top of display" is the reference point for the high-precision/
  92 * corrected timestamp.
  93 *
  94 * On a lot of display hardware, programming needs to take effect during the
  95 * vertical blanking period so that settings like gamma, the image buffer
  96 * buffer to be scanned out, etc. can safely be changed without showing
  97 * any visual artifacts on the screen. In some unforgiving hardware, some of
  98 * this programming has to both start and end in the same vblank. To help
  99 * with the timing of the hardware programming, an interrupt is usually
 100 * available to notify the driver when it can start the updating of registers.
 101 * The interrupt is in this context named the vblank interrupt.
 102 *
 103 * The vblank interrupt may be fired at different points depending on the
 104 * hardware. Some hardware implementations will fire the interrupt when the
 105 * new frame start, other implementations will fire the interrupt at different
 106 * points in time.
 107 *
 108 * Vertical blanking plays a major role in graphics rendering. To achieve
 109 * tear-free display, users must synchronize page flips and/or rendering to
 110 * vertical blanking. The DRM API offers ioctls to perform page flips
 111 * synchronized to vertical blanking and wait for vertical blanking.
 112 *
 113 * The DRM core handles most of the vertical blanking management logic, which
 114 * involves filtering out spurious interrupts, keeping race-free blanking
 115 * counters, coping with counter wrap-around and resets and keeping use counts.
 116 * It relies on the driver to generate vertical blanking interrupts and
 117 * optionally provide a hardware vertical blanking counter.
 118 *
 119 * Drivers must initialize the vertical blanking handling core with a call to
 120 * drm_vblank_init(). Minimally, a driver needs to implement
 121 * &drm_crtc_funcs.enable_vblank and &drm_crtc_funcs.disable_vblank plus call
 122 * drm_crtc_handle_vblank() in its vblank interrupt handler for working vblank
 123 * support.
 124 *
 125 * Vertical blanking interrupts can be enabled by the DRM core or by drivers
 126 * themselves (for instance to handle page flipping operations).  The DRM core
 127 * maintains a vertical blanking use count to ensure that the interrupts are not
 128 * disabled while a user still needs them. To increment the use count, drivers
 129 * call drm_crtc_vblank_get() and release the vblank reference again with
 130 * drm_crtc_vblank_put(). In between these two calls vblank interrupts are
 131 * guaranteed to be enabled.
 132 *
 133 * On many hardware disabling the vblank interrupt cannot be done in a race-free
 134 * manner, see &drm_driver.vblank_disable_immediate and
 135 * &drm_driver.max_vblank_count. In that case the vblank core only disables the
 136 * vblanks after a timer has expired, which can be configured through the
 137 * ``vblankoffdelay`` module parameter.
 138 *
 139 * Drivers for hardware without support for vertical-blanking interrupts
 140 * must not call drm_vblank_init(). For such drivers, atomic helpers will
 141 * automatically generate fake vblank events as part of the display update.
 142 * This functionality also can be controlled by the driver by enabling and
 143 * disabling struct drm_crtc_state.no_vblank.
 144 */
 145
 146/* Retry timestamp calculation up to 3 times to satisfy
 147 * drm_timestamp_precision before giving up.
 148 */
 149#define DRM_TIMESTAMP_MAXRETRIES 3
 150
 151/* Threshold in nanoseconds for detection of redundant
 152 * vblank irq in drm_handle_vblank(). 1 msec should be ok.
 153 */
 154#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
 155
 156static bool
 157drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
 158			  ktime_t *tvblank, bool in_vblank_irq);
 159
 160static unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
 161
 162static int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
 163
 164module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
 165module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
 166MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs] (0: never disable, <0: disable immediately)");
 167MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
 168
 169static void store_vblank(struct drm_device *dev, unsigned int pipe,
 170			 u32 vblank_count_inc,
 171			 ktime_t t_vblank, u32 last)
 172{
 173	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 174
 175	assert_spin_locked(&dev->vblank_time_lock);
 176
 177	vblank->last = last;
 178
 179	write_seqlock(&vblank->seqlock);
 180	vblank->time = t_vblank;
 181	atomic64_add(vblank_count_inc, &vblank->count);
 182	write_sequnlock(&vblank->seqlock);
 183}
 184
 185static u32 drm_max_vblank_count(struct drm_device *dev, unsigned int pipe)
 186{
 187	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 188
 189	return vblank->max_vblank_count ?: dev->max_vblank_count;
 190}
 191
 192/*
 193 * "No hw counter" fallback implementation of .get_vblank_counter() hook,
 194 * if there is no useable hardware frame counter available.
 195 */
 196static u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe)
 197{
 198	drm_WARN_ON_ONCE(dev, drm_max_vblank_count(dev, pipe) != 0);
 199	return 0;
 200}
 201
 202static u32 __get_vblank_counter(struct drm_device *dev, unsigned int pipe)
 203{
 204	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 205		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
 206
 207		if (drm_WARN_ON(dev, !crtc))
 208			return 0;
 209
 210		if (crtc->funcs->get_vblank_counter)
 211			return crtc->funcs->get_vblank_counter(crtc);
 212	} else if (dev->driver->get_vblank_counter) {
 
 
 213		return dev->driver->get_vblank_counter(dev, pipe);
 214	}
 
 215
 216	return drm_vblank_no_hw_counter(dev, pipe);
 217}
 218
 219/*
 220 * Reset the stored timestamp for the current vblank count to correspond
 221 * to the last vblank occurred.
 222 *
 223 * Only to be called from drm_crtc_vblank_on().
 224 *
 225 * Note: caller must hold &drm_device.vbl_lock since this reads & writes
 226 * device vblank fields.
 227 */
 228static void drm_reset_vblank_timestamp(struct drm_device *dev, unsigned int pipe)
 229{
 230	u32 cur_vblank;
 231	bool rc;
 232	ktime_t t_vblank;
 233	int count = DRM_TIMESTAMP_MAXRETRIES;
 234
 235	spin_lock(&dev->vblank_time_lock);
 236
 237	/*
 238	 * sample the current counter to avoid random jumps
 239	 * when drm_vblank_enable() applies the diff
 240	 */
 241	do {
 242		cur_vblank = __get_vblank_counter(dev, pipe);
 243		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
 244	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
 245
 246	/*
 247	 * Only reinitialize corresponding vblank timestamp if high-precision query
 248	 * available and didn't fail. Otherwise reinitialize delayed at next vblank
 249	 * interrupt and assign 0 for now, to mark the vblanktimestamp as invalid.
 250	 */
 251	if (!rc)
 252		t_vblank = 0;
 253
 254	/*
 255	 * +1 to make sure user will never see the same
 256	 * vblank counter value before and after a modeset
 257	 */
 258	store_vblank(dev, pipe, 1, t_vblank, cur_vblank);
 259
 260	spin_unlock(&dev->vblank_time_lock);
 261}
 262
 263/*
 264 * Call back into the driver to update the appropriate vblank counter
 265 * (specified by @pipe).  Deal with wraparound, if it occurred, and
 266 * update the last read value so we can deal with wraparound on the next
 267 * call if necessary.
 268 *
 269 * Only necessary when going from off->on, to account for frames we
 270 * didn't get an interrupt for.
 271 *
 272 * Note: caller must hold &drm_device.vbl_lock since this reads & writes
 273 * device vblank fields.
 274 */
 275static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
 276				    bool in_vblank_irq)
 277{
 278	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 279	u32 cur_vblank, diff;
 280	bool rc;
 281	ktime_t t_vblank;
 282	int count = DRM_TIMESTAMP_MAXRETRIES;
 283	int framedur_ns = vblank->framedur_ns;
 284	u32 max_vblank_count = drm_max_vblank_count(dev, pipe);
 285
 286	/*
 287	 * Interrupts were disabled prior to this call, so deal with counter
 288	 * wrap if needed.
 289	 * NOTE!  It's possible we lost a full dev->max_vblank_count + 1 events
 290	 * here if the register is small or we had vblank interrupts off for
 291	 * a long time.
 292	 *
 293	 * We repeat the hardware vblank counter & timestamp query until
 294	 * we get consistent results. This to prevent races between gpu
 295	 * updating its hardware counter while we are retrieving the
 296	 * corresponding vblank timestamp.
 297	 */
 298	do {
 299		cur_vblank = __get_vblank_counter(dev, pipe);
 300		rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, in_vblank_irq);
 301	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
 302
 303	if (max_vblank_count) {
 304		/* trust the hw counter when it's around */
 305		diff = (cur_vblank - vblank->last) & max_vblank_count;
 306	} else if (rc && framedur_ns) {
 307		u64 diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
 308
 309		/*
 310		 * Figure out how many vblanks we've missed based
 311		 * on the difference in the timestamps and the
 312		 * frame/field duration.
 313		 */
 314
 315		drm_dbg_vbl(dev, "crtc %u: Calculating number of vblanks."
 316			    " diff_ns = %lld, framedur_ns = %d)\n",
 317			    pipe, (long long)diff_ns, framedur_ns);
 318
 319		diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
 320
 321		if (diff == 0 && in_vblank_irq)
 322			drm_dbg_vbl(dev, "crtc %u: Redundant vblirq ignored\n",
 323				    pipe);
 324	} else {
 325		/* some kind of default for drivers w/o accurate vbl timestamping */
 326		diff = in_vblank_irq ? 1 : 0;
 327	}
 328
 329	/*
 330	 * Within a drm_vblank_pre_modeset - drm_vblank_post_modeset
 331	 * interval? If so then vblank irqs keep running and it will likely
 332	 * happen that the hardware vblank counter is not trustworthy as it
 333	 * might reset at some point in that interval and vblank timestamps
 334	 * are not trustworthy either in that interval. Iow. this can result
 335	 * in a bogus diff >> 1 which must be avoided as it would cause
 336	 * random large forward jumps of the software vblank counter.
 337	 */
 338	if (diff > 1 && (vblank->inmodeset & 0x2)) {
 339		drm_dbg_vbl(dev,
 340			    "clamping vblank bump to 1 on crtc %u: diffr=%u"
 341			    " due to pre-modeset.\n", pipe, diff);
 342		diff = 1;
 343	}
 344
 345	drm_dbg_vbl(dev, "updating vblank count on crtc %u:"
 346		    " current=%llu, diff=%u, hw=%u hw_last=%u\n",
 347		    pipe, (unsigned long long)atomic64_read(&vblank->count),
 348		    diff, cur_vblank, vblank->last);
 349
 350	if (diff == 0) {
 351		drm_WARN_ON_ONCE(dev, cur_vblank != vblank->last);
 352		return;
 353	}
 354
 355	/*
 356	 * Only reinitialize corresponding vblank timestamp if high-precision query
 357	 * available and didn't fail, or we were called from the vblank interrupt.
 358	 * Otherwise reinitialize delayed at next vblank interrupt and assign 0
 359	 * for now, to mark the vblanktimestamp as invalid.
 360	 */
 361	if (!rc && !in_vblank_irq)
 362		t_vblank = 0;
 363
 364	store_vblank(dev, pipe, diff, t_vblank, cur_vblank);
 365}
 366
 367u64 drm_vblank_count(struct drm_device *dev, unsigned int pipe)
 368{
 369	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 370	u64 count;
 371
 372	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
 373		return 0;
 374
 375	count = atomic64_read(&vblank->count);
 376
 377	/*
 378	 * This read barrier corresponds to the implicit write barrier of the
 379	 * write seqlock in store_vblank(). Note that this is the only place
 380	 * where we need an explicit barrier, since all other access goes
 381	 * through drm_vblank_count_and_time(), which already has the required
 382	 * read barrier curtesy of the read seqlock.
 383	 */
 384	smp_rmb();
 385
 386	return count;
 387}
 388
 389/**
 390 * drm_crtc_accurate_vblank_count - retrieve the master vblank counter
 391 * @crtc: which counter to retrieve
 392 *
 393 * This function is similar to drm_crtc_vblank_count() but this function
 394 * interpolates to handle a race with vblank interrupts using the high precision
 395 * timestamping support.
 396 *
 397 * This is mostly useful for hardware that can obtain the scanout position, but
 398 * doesn't have a hardware frame counter.
 399 */
 400u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
 401{
 402	struct drm_device *dev = crtc->dev;
 403	unsigned int pipe = drm_crtc_index(crtc);
 404	u64 vblank;
 405	unsigned long flags;
 406
 407	drm_WARN_ONCE(dev, drm_debug_enabled(DRM_UT_VBL) &&
 408		      !crtc->funcs->get_vblank_timestamp,
 409		      "This function requires support for accurate vblank timestamps.");
 410
 411	spin_lock_irqsave(&dev->vblank_time_lock, flags);
 412
 413	drm_update_vblank_count(dev, pipe, false);
 414	vblank = drm_vblank_count(dev, pipe);
 415
 416	spin_unlock_irqrestore(&dev->vblank_time_lock, flags);
 417
 418	return vblank;
 419}
 420EXPORT_SYMBOL(drm_crtc_accurate_vblank_count);
 421
 422static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
 423{
 424	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 425		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
 426
 427		if (drm_WARN_ON(dev, !crtc))
 428			return;
 429
 430		if (crtc->funcs->disable_vblank)
 431			crtc->funcs->disable_vblank(crtc);
 432	} else {
 
 
 433		dev->driver->disable_vblank(dev, pipe);
 434	}
 
 435}
 436
 437/*
 438 * Disable vblank irq's on crtc, make sure that last vblank count
 439 * of hardware and corresponding consistent software vblank counter
 440 * are preserved, even if there are any spurious vblank irq's after
 441 * disable.
 442 */
 443void drm_vblank_disable_and_save(struct drm_device *dev, unsigned int pipe)
 444{
 445	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 446	unsigned long irqflags;
 447
 448	assert_spin_locked(&dev->vbl_lock);
 449
 450	/* Prevent vblank irq processing while disabling vblank irqs,
 451	 * so no updates of timestamps or count can happen after we've
 452	 * disabled. Needed to prevent races in case of delayed irq's.
 453	 */
 454	spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
 455
 456	/*
 457	 * Update vblank count and disable vblank interrupts only if the
 458	 * interrupts were enabled. This avoids calling the ->disable_vblank()
 459	 * operation in atomic context with the hardware potentially runtime
 460	 * suspended.
 461	 */
 462	if (!vblank->enabled)
 463		goto out;
 464
 465	/*
 466	 * Update the count and timestamp to maintain the
 467	 * appearance that the counter has been ticking all along until
 468	 * this time. This makes the count account for the entire time
 469	 * between drm_crtc_vblank_on() and drm_crtc_vblank_off().
 470	 */
 471	drm_update_vblank_count(dev, pipe, false);
 472	__disable_vblank(dev, pipe);
 473	vblank->enabled = false;
 474
 475out:
 476	spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
 477}
 478
 479static void vblank_disable_fn(struct timer_list *t)
 480{
 481	struct drm_vblank_crtc *vblank = from_timer(vblank, t, disable_timer);
 482	struct drm_device *dev = vblank->dev;
 483	unsigned int pipe = vblank->pipe;
 484	unsigned long irqflags;
 485
 486	spin_lock_irqsave(&dev->vbl_lock, irqflags);
 487	if (atomic_read(&vblank->refcount) == 0 && vblank->enabled) {
 488		drm_dbg_core(dev, "disabling vblank on crtc %u\n", pipe);
 489		drm_vblank_disable_and_save(dev, pipe);
 490	}
 491	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 492}
 493
 494static void drm_vblank_init_release(struct drm_device *dev, void *ptr)
 495{
 496	struct drm_vblank_crtc *vblank = ptr;
 497
 498	drm_WARN_ON(dev, READ_ONCE(vblank->enabled) &&
 499		    drm_core_check_feature(dev, DRIVER_MODESET));
 500
 501	drm_vblank_destroy_worker(vblank);
 502	del_timer_sync(&vblank->disable_timer);
 503}
 504
 505/**
 506 * drm_vblank_init - initialize vblank support
 507 * @dev: DRM device
 508 * @num_crtcs: number of CRTCs supported by @dev
 509 *
 510 * This function initializes vblank support for @num_crtcs display pipelines.
 511 * Cleanup is handled automatically through a cleanup function added with
 512 * drmm_add_action_or_reset().
 513 *
 514 * Returns:
 515 * Zero on success or a negative error code on failure.
 516 */
 517int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs)
 518{
 519	int ret;
 520	unsigned int i;
 521
 522	spin_lock_init(&dev->vbl_lock);
 523	spin_lock_init(&dev->vblank_time_lock);
 524
 525	dev->vblank = drmm_kcalloc(dev, num_crtcs, sizeof(*dev->vblank), GFP_KERNEL);
 526	if (!dev->vblank)
 527		return -ENOMEM;
 528
 529	dev->num_crtcs = num_crtcs;
 530
 531	for (i = 0; i < num_crtcs; i++) {
 532		struct drm_vblank_crtc *vblank = &dev->vblank[i];
 533
 534		vblank->dev = dev;
 535		vblank->pipe = i;
 536		init_waitqueue_head(&vblank->queue);
 537		timer_setup(&vblank->disable_timer, vblank_disable_fn, 0);
 538		seqlock_init(&vblank->seqlock);
 539
 540		ret = drmm_add_action_or_reset(dev, drm_vblank_init_release,
 541					       vblank);
 542		if (ret)
 543			return ret;
 544
 545		ret = drm_vblank_worker_init(vblank);
 546		if (ret)
 547			return ret;
 548	}
 549
 550	return 0;
 551}
 552EXPORT_SYMBOL(drm_vblank_init);
 553
 554/**
 555 * drm_dev_has_vblank - test if vblanking has been initialized for
 556 *                      a device
 557 * @dev: the device
 558 *
 559 * Drivers may call this function to test if vblank support is
 560 * initialized for a device. For most hardware this means that vblanking
 561 * can also be enabled.
 562 *
 563 * Atomic helpers use this function to initialize
 564 * &drm_crtc_state.no_vblank. See also drm_atomic_helper_check_modeset().
 565 *
 566 * Returns:
 567 * True if vblanking has been initialized for the given device, false
 568 * otherwise.
 569 */
 570bool drm_dev_has_vblank(const struct drm_device *dev)
 571{
 572	return dev->num_crtcs != 0;
 573}
 574EXPORT_SYMBOL(drm_dev_has_vblank);
 575
 576/**
 577 * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
 578 * @crtc: which CRTC's vblank waitqueue to retrieve
 579 *
 580 * This function returns a pointer to the vblank waitqueue for the CRTC.
 581 * Drivers can use this to implement vblank waits using wait_event() and related
 582 * functions.
 583 */
 584wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
 585{
 586	return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
 587}
 588EXPORT_SYMBOL(drm_crtc_vblank_waitqueue);
 589
 590
 591/**
 592 * drm_calc_timestamping_constants - calculate vblank timestamp constants
 593 * @crtc: drm_crtc whose timestamp constants should be updated.
 594 * @mode: display mode containing the scanout timings
 595 *
 596 * Calculate and store various constants which are later needed by vblank and
 597 * swap-completion timestamping, e.g, by
 598 * drm_crtc_vblank_helper_get_vblank_timestamp(). They are derived from
 599 * CRTC's true scanout timing, so they take things like panel scaling or
 600 * other adjustments into account.
 601 */
 602void drm_calc_timestamping_constants(struct drm_crtc *crtc,
 603				     const struct drm_display_mode *mode)
 604{
 605	struct drm_device *dev = crtc->dev;
 606	unsigned int pipe = drm_crtc_index(crtc);
 607	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 608	int linedur_ns = 0, framedur_ns = 0;
 609	int dotclock = mode->crtc_clock;
 610
 611	if (!drm_dev_has_vblank(dev))
 612		return;
 613
 614	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
 615		return;
 616
 617	/* Valid dotclock? */
 618	if (dotclock > 0) {
 619		int frame_size = mode->crtc_htotal * mode->crtc_vtotal;
 620
 621		/*
 622		 * Convert scanline length in pixels and video
 623		 * dot clock to line duration and frame duration
 624		 * in nanoseconds:
 625		 */
 626		linedur_ns  = div_u64((u64) mode->crtc_htotal * 1000000, dotclock);
 627		framedur_ns = div_u64((u64) frame_size * 1000000, dotclock);
 628
 629		/*
 630		 * Fields of interlaced scanout modes are only half a frame duration.
 631		 */
 632		if (mode->flags & DRM_MODE_FLAG_INTERLACE)
 633			framedur_ns /= 2;
 634	} else {
 635		drm_err(dev, "crtc %u: Can't calculate constants, dotclock = 0!\n",
 636			crtc->base.id);
 637	}
 638
 639	vblank->linedur_ns  = linedur_ns;
 640	vblank->framedur_ns = framedur_ns;
 641	vblank->hwmode = *mode;
 642
 643	drm_dbg_core(dev,
 644		     "crtc %u: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
 645		     crtc->base.id, mode->crtc_htotal,
 646		     mode->crtc_vtotal, mode->crtc_vdisplay);
 647	drm_dbg_core(dev, "crtc %u: clock %d kHz framedur %d linedur %d\n",
 648		     crtc->base.id, dotclock, framedur_ns, linedur_ns);
 649}
 650EXPORT_SYMBOL(drm_calc_timestamping_constants);
 651
 652/**
 653 * drm_crtc_vblank_helper_get_vblank_timestamp_internal - precise vblank
 654 *                                                        timestamp helper
 655 * @crtc: CRTC whose vblank timestamp to retrieve
 656 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
 657 *             On return contains true maximum error of timestamp
 658 * @vblank_time: Pointer to time which should receive the timestamp
 659 * @in_vblank_irq:
 660 *     True when called from drm_crtc_handle_vblank().  Some drivers
 661 *     need to apply some workarounds for gpu-specific vblank irq quirks
 662 *     if flag is set.
 663 * @get_scanout_position:
 664 *     Callback function to retrieve the scanout position. See
 665 *     @struct drm_crtc_helper_funcs.get_scanout_position.
 666 *
 667 * Implements calculation of exact vblank timestamps from given drm_display_mode
 668 * timings and current video scanout position of a CRTC.
 669 *
 670 * The current implementation only handles standard video modes. For double scan
 671 * and interlaced modes the driver is supposed to adjust the hardware mode
 672 * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
 673 * match the scanout position reported.
 674 *
 675 * Note that atomic drivers must call drm_calc_timestamping_constants() before
 676 * enabling a CRTC. The atomic helpers already take care of that in
 677 * drm_atomic_helper_update_legacy_modeset_state().
 678 *
 679 * Returns:
 680 *
 681 * Returns true on success, and false on failure, i.e. when no accurate
 682 * timestamp could be acquired.
 683 */
 684bool
 685drm_crtc_vblank_helper_get_vblank_timestamp_internal(
 686	struct drm_crtc *crtc, int *max_error, ktime_t *vblank_time,
 687	bool in_vblank_irq,
 688	drm_vblank_get_scanout_position_func get_scanout_position)
 689{
 690	struct drm_device *dev = crtc->dev;
 691	unsigned int pipe = crtc->index;
 692	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 693	struct timespec64 ts_etime, ts_vblank_time;
 694	ktime_t stime, etime;
 695	bool vbl_status;
 696	const struct drm_display_mode *mode;
 697	int vpos, hpos, i;
 698	int delta_ns, duration_ns;
 699
 700	if (pipe >= dev->num_crtcs) {
 701		drm_err(dev, "Invalid crtc %u\n", pipe);
 702		return false;
 703	}
 704
 705	/* Scanout position query not supported? Should not happen. */
 706	if (!get_scanout_position) {
 707		drm_err(dev, "Called from CRTC w/o get_scanout_position()!?\n");
 708		return false;
 709	}
 710
 711	if (drm_drv_uses_atomic_modeset(dev))
 712		mode = &vblank->hwmode;
 713	else
 714		mode = &crtc->hwmode;
 715
 716	/* If mode timing undefined, just return as no-op:
 717	 * Happens during initial modesetting of a crtc.
 718	 */
 719	if (mode->crtc_clock == 0) {
 720		drm_dbg_core(dev, "crtc %u: Noop due to uninitialized mode.\n",
 721			     pipe);
 722		drm_WARN_ON_ONCE(dev, drm_drv_uses_atomic_modeset(dev));
 723		return false;
 724	}
 725
 726	/* Get current scanout position with system timestamp.
 727	 * Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
 728	 * if single query takes longer than max_error nanoseconds.
 729	 *
 730	 * This guarantees a tight bound on maximum error if
 731	 * code gets preempted or delayed for some reason.
 732	 */
 733	for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
 734		/*
 735		 * Get vertical and horizontal scanout position vpos, hpos,
 736		 * and bounding timestamps stime, etime, pre/post query.
 737		 */
 738		vbl_status = get_scanout_position(crtc, in_vblank_irq,
 739						  &vpos, &hpos,
 740						  &stime, &etime,
 741						  mode);
 742
 743		/* Return as no-op if scanout query unsupported or failed. */
 744		if (!vbl_status) {
 745			drm_dbg_core(dev,
 746				     "crtc %u : scanoutpos query failed.\n",
 747				     pipe);
 748			return false;
 749		}
 750
 751		/* Compute uncertainty in timestamp of scanout position query. */
 752		duration_ns = ktime_to_ns(etime) - ktime_to_ns(stime);
 753
 754		/* Accept result with <  max_error nsecs timing uncertainty. */
 755		if (duration_ns <= *max_error)
 756			break;
 757	}
 758
 759	/* Noisy system timing? */
 760	if (i == DRM_TIMESTAMP_MAXRETRIES) {
 761		drm_dbg_core(dev,
 762			     "crtc %u: Noisy timestamp %d us > %d us [%d reps].\n",
 763			     pipe, duration_ns / 1000, *max_error / 1000, i);
 764	}
 765
 766	/* Return upper bound of timestamp precision error. */
 767	*max_error = duration_ns;
 768
 769	/* Convert scanout position into elapsed time at raw_time query
 770	 * since start of scanout at first display scanline. delta_ns
 771	 * can be negative if start of scanout hasn't happened yet.
 772	 */
 773	delta_ns = div_s64(1000000LL * (vpos * mode->crtc_htotal + hpos),
 774			   mode->crtc_clock);
 775
 776	/* Subtract time delta from raw timestamp to get final
 777	 * vblank_time timestamp for end of vblank.
 778	 */
 779	*vblank_time = ktime_sub_ns(etime, delta_ns);
 780
 781	if (!drm_debug_enabled(DRM_UT_VBL))
 782		return true;
 783
 784	ts_etime = ktime_to_timespec64(etime);
 785	ts_vblank_time = ktime_to_timespec64(*vblank_time);
 786
 787	drm_dbg_vbl(dev,
 788		    "crtc %u : v p(%d,%d)@ %lld.%06ld -> %lld.%06ld [e %d us, %d rep]\n",
 789		    pipe, hpos, vpos,
 790		    (u64)ts_etime.tv_sec, ts_etime.tv_nsec / 1000,
 791		    (u64)ts_vblank_time.tv_sec, ts_vblank_time.tv_nsec / 1000,
 792		    duration_ns / 1000, i);
 793
 794	return true;
 795}
 796EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp_internal);
 797
 798/**
 799 * drm_crtc_vblank_helper_get_vblank_timestamp - precise vblank timestamp
 800 *                                               helper
 801 * @crtc: CRTC whose vblank timestamp to retrieve
 802 * @max_error: Desired maximum allowable error in timestamps (nanosecs)
 803 *             On return contains true maximum error of timestamp
 804 * @vblank_time: Pointer to time which should receive the timestamp
 805 * @in_vblank_irq:
 806 *     True when called from drm_crtc_handle_vblank().  Some drivers
 807 *     need to apply some workarounds for gpu-specific vblank irq quirks
 808 *     if flag is set.
 809 *
 810 * Implements calculation of exact vblank timestamps from given drm_display_mode
 811 * timings and current video scanout position of a CRTC. This can be directly
 812 * used as the &drm_crtc_funcs.get_vblank_timestamp implementation of a kms
 813 * driver if &drm_crtc_helper_funcs.get_scanout_position is implemented.
 814 *
 815 * The current implementation only handles standard video modes. For double scan
 816 * and interlaced modes the driver is supposed to adjust the hardware mode
 817 * (taken from &drm_crtc_state.adjusted mode for atomic modeset drivers) to
 818 * match the scanout position reported.
 819 *
 820 * Note that atomic drivers must call drm_calc_timestamping_constants() before
 821 * enabling a CRTC. The atomic helpers already take care of that in
 822 * drm_atomic_helper_update_legacy_modeset_state().
 823 *
 824 * Returns:
 825 *
 826 * Returns true on success, and false on failure, i.e. when no accurate
 827 * timestamp could be acquired.
 828 */
 829bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
 830						 int *max_error,
 831						 ktime_t *vblank_time,
 832						 bool in_vblank_irq)
 833{
 834	return drm_crtc_vblank_helper_get_vblank_timestamp_internal(
 835		crtc, max_error, vblank_time, in_vblank_irq,
 836		crtc->helper_private->get_scanout_position);
 837}
 838EXPORT_SYMBOL(drm_crtc_vblank_helper_get_vblank_timestamp);
 839
 840/**
 841 * drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
 842 *                             vblank interval
 843 * @dev: DRM device
 844 * @pipe: index of CRTC whose vblank timestamp to retrieve
 845 * @tvblank: Pointer to target time which should receive the timestamp
 846 * @in_vblank_irq:
 847 *     True when called from drm_crtc_handle_vblank().  Some drivers
 848 *     need to apply some workarounds for gpu-specific vblank irq quirks
 849 *     if flag is set.
 850 *
 851 * Fetches the system timestamp corresponding to the time of the most recent
 852 * vblank interval on specified CRTC. May call into kms-driver to
 853 * compute the timestamp with a high-precision GPU specific method.
 854 *
 855 * Returns zero if timestamp originates from uncorrected do_gettimeofday()
 856 * call, i.e., it isn't very precisely locked to the true vblank.
 857 *
 858 * Returns:
 859 * True if timestamp is considered to be very precise, false otherwise.
 860 */
 861static bool
 862drm_get_last_vbltimestamp(struct drm_device *dev, unsigned int pipe,
 863			  ktime_t *tvblank, bool in_vblank_irq)
 864{
 865	struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
 866	bool ret = false;
 867
 868	/* Define requested maximum error on timestamps (nanoseconds). */
 869	int max_error = (int) drm_timestamp_precision * 1000;
 870
 871	/* Query driver if possible and precision timestamping enabled. */
 872	if (crtc && crtc->funcs->get_vblank_timestamp && max_error > 0) {
 873		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
 874
 875		ret = crtc->funcs->get_vblank_timestamp(crtc, &max_error,
 876							tvblank, in_vblank_irq);
 877	}
 878
 879	/* GPU high precision timestamp query unsupported or failed.
 880	 * Return current monotonic/gettimeofday timestamp as best estimate.
 881	 */
 882	if (!ret)
 883		*tvblank = ktime_get();
 884
 885	return ret;
 886}
 887
 888/**
 889 * drm_crtc_vblank_count - retrieve "cooked" vblank counter value
 890 * @crtc: which counter to retrieve
 891 *
 892 * Fetches the "cooked" vblank count value that represents the number of
 893 * vblank events since the system was booted, including lost events due to
 894 * modesetting activity. Note that this timer isn't correct against a racing
 895 * vblank interrupt (since it only reports the software vblank counter), see
 896 * drm_crtc_accurate_vblank_count() for such use-cases.
 897 *
 898 * Note that for a given vblank counter value drm_crtc_handle_vblank()
 899 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
 900 * provide a barrier: Any writes done before calling
 901 * drm_crtc_handle_vblank() will be visible to callers of the later
 902 * functions, iff the vblank count is the same or a later one.
 903 *
 904 * See also &drm_vblank_crtc.count.
 905 *
 906 * Returns:
 907 * The software vblank counter.
 908 */
 909u64 drm_crtc_vblank_count(struct drm_crtc *crtc)
 910{
 911	return drm_vblank_count(crtc->dev, drm_crtc_index(crtc));
 912}
 913EXPORT_SYMBOL(drm_crtc_vblank_count);
 914
 915/**
 916 * drm_vblank_count_and_time - retrieve "cooked" vblank counter value and the
 917 *     system timestamp corresponding to that vblank counter value.
 918 * @dev: DRM device
 919 * @pipe: index of CRTC whose counter to retrieve
 920 * @vblanktime: Pointer to ktime_t to receive the vblank timestamp.
 921 *
 922 * Fetches the "cooked" vblank count value that represents the number of
 923 * vblank events since the system was booted, including lost events due to
 924 * modesetting activity. Returns corresponding system timestamp of the time
 925 * of the vblank interval that corresponds to the current vblank counter value.
 926 *
 927 * This is the legacy version of drm_crtc_vblank_count_and_time().
 928 */
 929static u64 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
 930				     ktime_t *vblanktime)
 931{
 932	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
 933	u64 vblank_count;
 934	unsigned int seq;
 935
 936	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs)) {
 937		*vblanktime = 0;
 938		return 0;
 939	}
 940
 941	do {
 942		seq = read_seqbegin(&vblank->seqlock);
 943		vblank_count = atomic64_read(&vblank->count);
 944		*vblanktime = vblank->time;
 945	} while (read_seqretry(&vblank->seqlock, seq));
 946
 947	return vblank_count;
 948}
 949
 950/**
 951 * drm_crtc_vblank_count_and_time - retrieve "cooked" vblank counter value
 952 *     and the system timestamp corresponding to that vblank counter value
 953 * @crtc: which counter to retrieve
 954 * @vblanktime: Pointer to time to receive the vblank timestamp.
 955 *
 956 * Fetches the "cooked" vblank count value that represents the number of
 957 * vblank events since the system was booted, including lost events due to
 958 * modesetting activity. Returns corresponding system timestamp of the time
 959 * of the vblank interval that corresponds to the current vblank counter value.
 960 *
 961 * Note that for a given vblank counter value drm_crtc_handle_vblank()
 962 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
 963 * provide a barrier: Any writes done before calling
 964 * drm_crtc_handle_vblank() will be visible to callers of the later
 965 * functions, iff the vblank count is the same or a later one.
 966 *
 967 * See also &drm_vblank_crtc.count.
 968 */
 969u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
 970				   ktime_t *vblanktime)
 971{
 972	return drm_vblank_count_and_time(crtc->dev, drm_crtc_index(crtc),
 973					 vblanktime);
 974}
 975EXPORT_SYMBOL(drm_crtc_vblank_count_and_time);
 976
 977static void send_vblank_event(struct drm_device *dev,
 978		struct drm_pending_vblank_event *e,
 979		u64 seq, ktime_t now)
 980{
 981	struct timespec64 tv;
 982
 983	switch (e->event.base.type) {
 984	case DRM_EVENT_VBLANK:
 985	case DRM_EVENT_FLIP_COMPLETE:
 986		tv = ktime_to_timespec64(now);
 987		e->event.vbl.sequence = seq;
 988		/*
 989		 * e->event is a user space structure, with hardcoded unsigned
 990		 * 32-bit seconds/microseconds. This is safe as we always use
 991		 * monotonic timestamps since linux-4.15
 992		 */
 993		e->event.vbl.tv_sec = tv.tv_sec;
 994		e->event.vbl.tv_usec = tv.tv_nsec / 1000;
 995		break;
 996	case DRM_EVENT_CRTC_SEQUENCE:
 997		if (seq)
 998			e->event.seq.sequence = seq;
 999		e->event.seq.time_ns = ktime_to_ns(now);
1000		break;
1001	}
1002	trace_drm_vblank_event_delivered(e->base.file_priv, e->pipe, seq);
1003	drm_send_event_locked(dev, &e->base);
 
 
 
 
 
 
 
1004}
1005
1006/**
1007 * drm_crtc_arm_vblank_event - arm vblank event after pageflip
1008 * @crtc: the source CRTC of the vblank event
1009 * @e: the event to send
1010 *
1011 * A lot of drivers need to generate vblank events for the very next vblank
1012 * interrupt. For example when the page flip interrupt happens when the page
1013 * flip gets armed, but not when it actually executes within the next vblank
1014 * period. This helper function implements exactly the required vblank arming
1015 * behaviour.
1016 *
1017 * NOTE: Drivers using this to send out the &drm_crtc_state.event as part of an
1018 * atomic commit must ensure that the next vblank happens at exactly the same
1019 * time as the atomic commit is committed to the hardware. This function itself
1020 * does **not** protect against the next vblank interrupt racing with either this
1021 * function call or the atomic commit operation. A possible sequence could be:
1022 *
1023 * 1. Driver commits new hardware state into vblank-synchronized registers.
1024 * 2. A vblank happens, committing the hardware state. Also the corresponding
1025 *    vblank interrupt is fired off and fully processed by the interrupt
1026 *    handler.
1027 * 3. The atomic commit operation proceeds to call drm_crtc_arm_vblank_event().
1028 * 4. The event is only send out for the next vblank, which is wrong.
1029 *
1030 * An equivalent race can happen when the driver calls
1031 * drm_crtc_arm_vblank_event() before writing out the new hardware state.
1032 *
1033 * The only way to make this work safely is to prevent the vblank from firing
1034 * (and the hardware from committing anything else) until the entire atomic
1035 * commit sequence has run to completion. If the hardware does not have such a
1036 * feature (e.g. using a "go" bit), then it is unsafe to use this functions.
1037 * Instead drivers need to manually send out the event from their interrupt
1038 * handler by calling drm_crtc_send_vblank_event() and make sure that there's no
1039 * possible race with the hardware committing the atomic update.
1040 *
1041 * Caller must hold a vblank reference for the event @e acquired by a
1042 * drm_crtc_vblank_get(), which will be dropped when the next vblank arrives.
1043 */
1044void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
1045			       struct drm_pending_vblank_event *e)
1046{
1047	struct drm_device *dev = crtc->dev;
1048	unsigned int pipe = drm_crtc_index(crtc);
1049
1050	assert_spin_locked(&dev->event_lock);
1051
1052	e->pipe = pipe;
1053	e->sequence = drm_crtc_accurate_vblank_count(crtc) + 1;
1054	list_add_tail(&e->base.link, &dev->vblank_event_list);
1055}
1056EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
1057
1058/**
1059 * drm_crtc_send_vblank_event - helper to send vblank event after pageflip
1060 * @crtc: the source CRTC of the vblank event
1061 * @e: the event to send
1062 *
1063 * Updates sequence # and timestamp on event for the most recently processed
1064 * vblank, and sends it to userspace.  Caller must hold event lock.
1065 *
1066 * See drm_crtc_arm_vblank_event() for a helper which can be used in certain
1067 * situation, especially to send out events for atomic commit operations.
1068 */
1069void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
1070				struct drm_pending_vblank_event *e)
1071{
1072	struct drm_device *dev = crtc->dev;
1073	u64 seq;
1074	unsigned int pipe = drm_crtc_index(crtc);
1075	ktime_t now;
1076
1077	if (drm_dev_has_vblank(dev)) {
1078		seq = drm_vblank_count_and_time(dev, pipe, &now);
1079	} else {
1080		seq = 0;
1081
1082		now = ktime_get();
1083	}
1084	e->pipe = pipe;
1085	send_vblank_event(dev, e, seq, now);
1086}
1087EXPORT_SYMBOL(drm_crtc_send_vblank_event);
1088
1089static int __enable_vblank(struct drm_device *dev, unsigned int pipe)
1090{
1091	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1092		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
1093
1094		if (drm_WARN_ON(dev, !crtc))
1095			return 0;
1096
1097		if (crtc->funcs->enable_vblank)
1098			return crtc->funcs->enable_vblank(crtc);
1099	} else if (dev->driver->enable_vblank) {
 
 
1100		return dev->driver->enable_vblank(dev, pipe);
1101	}
 
1102
1103	return -EINVAL;
1104}
1105
1106static int drm_vblank_enable(struct drm_device *dev, unsigned int pipe)
1107{
1108	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1109	int ret = 0;
1110
1111	assert_spin_locked(&dev->vbl_lock);
1112
1113	spin_lock(&dev->vblank_time_lock);
1114
1115	if (!vblank->enabled) {
1116		/*
1117		 * Enable vblank irqs under vblank_time_lock protection.
1118		 * All vblank count & timestamp updates are held off
1119		 * until we are done reinitializing master counter and
1120		 * timestamps. Filtercode in drm_handle_vblank() will
1121		 * prevent double-accounting of same vblank interval.
1122		 */
1123		ret = __enable_vblank(dev, pipe);
1124		drm_dbg_core(dev, "enabling vblank on crtc %u, ret: %d\n",
1125			     pipe, ret);
1126		if (ret) {
1127			atomic_dec(&vblank->refcount);
1128		} else {
1129			drm_update_vblank_count(dev, pipe, 0);
1130			/* drm_update_vblank_count() includes a wmb so we just
1131			 * need to ensure that the compiler emits the write
1132			 * to mark the vblank as enabled after the call
1133			 * to drm_update_vblank_count().
1134			 */
1135			WRITE_ONCE(vblank->enabled, true);
1136		}
1137	}
1138
1139	spin_unlock(&dev->vblank_time_lock);
1140
1141	return ret;
1142}
1143
1144int drm_vblank_get(struct drm_device *dev, unsigned int pipe)
1145{
1146	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1147	unsigned long irqflags;
1148	int ret = 0;
1149
1150	if (!drm_dev_has_vblank(dev))
1151		return -EINVAL;
1152
1153	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1154		return -EINVAL;
1155
1156	spin_lock_irqsave(&dev->vbl_lock, irqflags);
1157	/* Going from 0->1 means we have to enable interrupts again */
1158	if (atomic_add_return(1, &vblank->refcount) == 1) {
1159		ret = drm_vblank_enable(dev, pipe);
1160	} else {
1161		if (!vblank->enabled) {
1162			atomic_dec(&vblank->refcount);
1163			ret = -EINVAL;
1164		}
1165	}
1166	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
1167
1168	return ret;
1169}
1170
1171/**
1172 * drm_crtc_vblank_get - get a reference count on vblank events
1173 * @crtc: which CRTC to own
1174 *
1175 * Acquire a reference count on vblank events to avoid having them disabled
1176 * while in use.
1177 *
1178 * Returns:
1179 * Zero on success or a negative error code on failure.
1180 */
1181int drm_crtc_vblank_get(struct drm_crtc *crtc)
1182{
1183	return drm_vblank_get(crtc->dev, drm_crtc_index(crtc));
1184}
1185EXPORT_SYMBOL(drm_crtc_vblank_get);
1186
1187void drm_vblank_put(struct drm_device *dev, unsigned int pipe)
1188{
1189	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1190
1191	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1192		return;
1193
1194	if (drm_WARN_ON(dev, atomic_read(&vblank->refcount) == 0))
1195		return;
1196
1197	/* Last user schedules interrupt disable */
1198	if (atomic_dec_and_test(&vblank->refcount)) {
1199		if (drm_vblank_offdelay == 0)
1200			return;
1201		else if (drm_vblank_offdelay < 0)
1202			vblank_disable_fn(&vblank->disable_timer);
1203		else if (!dev->vblank_disable_immediate)
1204			mod_timer(&vblank->disable_timer,
1205				  jiffies + ((drm_vblank_offdelay * HZ)/1000));
1206	}
1207}
1208
1209/**
1210 * drm_crtc_vblank_put - give up ownership of vblank events
1211 * @crtc: which counter to give up
1212 *
1213 * Release ownership of a given vblank counter, turning off interrupts
1214 * if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
1215 */
1216void drm_crtc_vblank_put(struct drm_crtc *crtc)
1217{
1218	drm_vblank_put(crtc->dev, drm_crtc_index(crtc));
1219}
1220EXPORT_SYMBOL(drm_crtc_vblank_put);
1221
1222/**
1223 * drm_wait_one_vblank - wait for one vblank
1224 * @dev: DRM device
1225 * @pipe: CRTC index
1226 *
1227 * This waits for one vblank to pass on @pipe, using the irq driver interfaces.
1228 * It is a failure to call this when the vblank irq for @pipe is disabled, e.g.
1229 * due to lack of driver support or because the crtc is off.
1230 *
1231 * This is the legacy version of drm_crtc_wait_one_vblank().
1232 */
1233void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe)
1234{
1235	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1236	int ret;
1237	u64 last;
1238
1239	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1240		return;
1241
1242	ret = drm_vblank_get(dev, pipe);
1243	if (drm_WARN(dev, ret, "vblank not available on crtc %i, ret=%i\n",
1244		     pipe, ret))
1245		return;
1246
1247	last = drm_vblank_count(dev, pipe);
1248
1249	ret = wait_event_timeout(vblank->queue,
1250				 last != drm_vblank_count(dev, pipe),
1251				 msecs_to_jiffies(100));
1252
1253	drm_WARN(dev, ret == 0, "vblank wait timed out on crtc %i\n", pipe);
1254
1255	drm_vblank_put(dev, pipe);
1256}
1257EXPORT_SYMBOL(drm_wait_one_vblank);
1258
1259/**
1260 * drm_crtc_wait_one_vblank - wait for one vblank
1261 * @crtc: DRM crtc
1262 *
1263 * This waits for one vblank to pass on @crtc, using the irq driver interfaces.
1264 * It is a failure to call this when the vblank irq for @crtc is disabled, e.g.
1265 * due to lack of driver support or because the crtc is off.
1266 */
1267void drm_crtc_wait_one_vblank(struct drm_crtc *crtc)
1268{
1269	drm_wait_one_vblank(crtc->dev, drm_crtc_index(crtc));
1270}
1271EXPORT_SYMBOL(drm_crtc_wait_one_vblank);
1272
1273/**
1274 * drm_crtc_vblank_off - disable vblank events on a CRTC
1275 * @crtc: CRTC in question
1276 *
1277 * Drivers can use this function to shut down the vblank interrupt handling when
1278 * disabling a crtc. This function ensures that the latest vblank frame count is
1279 * stored so that drm_vblank_on can restore it again.
1280 *
1281 * Drivers must use this function when the hardware vblank counter can get
1282 * reset, e.g. when suspending or disabling the @crtc in general.
1283 */
1284void drm_crtc_vblank_off(struct drm_crtc *crtc)
1285{
1286	struct drm_device *dev = crtc->dev;
1287	unsigned int pipe = drm_crtc_index(crtc);
1288	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1289	struct drm_pending_vblank_event *e, *t;
1290	ktime_t now;
1291	u64 seq;
1292
1293	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1294		return;
1295
1296	/*
1297	 * Grab event_lock early to prevent vblank work from being scheduled
1298	 * while we're in the middle of shutting down vblank interrupts
1299	 */
1300	spin_lock_irq(&dev->event_lock);
1301
1302	spin_lock(&dev->vbl_lock);
1303	drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n",
1304		    pipe, vblank->enabled, vblank->inmodeset);
1305
1306	/* Avoid redundant vblank disables without previous
1307	 * drm_crtc_vblank_on(). */
1308	if (drm_core_check_feature(dev, DRIVER_ATOMIC) || !vblank->inmodeset)
1309		drm_vblank_disable_and_save(dev, pipe);
1310
1311	wake_up(&vblank->queue);
1312
1313	/*
1314	 * Prevent subsequent drm_vblank_get() from re-enabling
1315	 * the vblank interrupt by bumping the refcount.
1316	 */
1317	if (!vblank->inmodeset) {
1318		atomic_inc(&vblank->refcount);
1319		vblank->inmodeset = 1;
1320	}
1321	spin_unlock(&dev->vbl_lock);
1322
1323	/* Send any queued vblank events, lest the natives grow disquiet */
1324	seq = drm_vblank_count_and_time(dev, pipe, &now);
1325
1326	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1327		if (e->pipe != pipe)
1328			continue;
1329		drm_dbg_core(dev, "Sending premature vblank event on disable: "
1330			     "wanted %llu, current %llu\n",
1331			     e->sequence, seq);
1332		list_del(&e->base.link);
1333		drm_vblank_put(dev, pipe);
1334		send_vblank_event(dev, e, seq, now);
1335	}
1336
1337	/* Cancel any leftover pending vblank work */
1338	drm_vblank_cancel_pending_works(vblank);
1339
1340	spin_unlock_irq(&dev->event_lock);
1341
1342	/* Will be reset by the modeset helpers when re-enabling the crtc by
1343	 * calling drm_calc_timestamping_constants(). */
1344	vblank->hwmode.crtc_clock = 0;
1345
1346	/* Wait for any vblank work that's still executing to finish */
1347	drm_vblank_flush_worker(vblank);
1348}
1349EXPORT_SYMBOL(drm_crtc_vblank_off);
1350
1351/**
1352 * drm_crtc_vblank_reset - reset vblank state to off on a CRTC
1353 * @crtc: CRTC in question
1354 *
1355 * Drivers can use this function to reset the vblank state to off at load time.
1356 * Drivers should use this together with the drm_crtc_vblank_off() and
1357 * drm_crtc_vblank_on() functions. The difference compared to
1358 * drm_crtc_vblank_off() is that this function doesn't save the vblank counter
1359 * and hence doesn't need to call any driver hooks.
1360 *
1361 * This is useful for recovering driver state e.g. on driver load, or on resume.
1362 */
1363void drm_crtc_vblank_reset(struct drm_crtc *crtc)
1364{
1365	struct drm_device *dev = crtc->dev;
1366	unsigned int pipe = drm_crtc_index(crtc);
1367	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1368
1369	spin_lock_irq(&dev->vbl_lock);
1370	/*
1371	 * Prevent subsequent drm_vblank_get() from enabling the vblank
1372	 * interrupt by bumping the refcount.
1373	 */
1374	if (!vblank->inmodeset) {
1375		atomic_inc(&vblank->refcount);
1376		vblank->inmodeset = 1;
1377	}
1378	spin_unlock_irq(&dev->vbl_lock);
1379
1380	drm_WARN_ON(dev, !list_empty(&dev->vblank_event_list));
1381	drm_WARN_ON(dev, !list_empty(&vblank->pending_work));
1382}
1383EXPORT_SYMBOL(drm_crtc_vblank_reset);
1384
1385/**
1386 * drm_crtc_set_max_vblank_count - configure the hw max vblank counter value
1387 * @crtc: CRTC in question
1388 * @max_vblank_count: max hardware vblank counter value
1389 *
1390 * Update the maximum hardware vblank counter value for @crtc
1391 * at runtime. Useful for hardware where the operation of the
1392 * hardware vblank counter depends on the currently active
1393 * display configuration.
1394 *
1395 * For example, if the hardware vblank counter does not work
1396 * when a specific connector is active the maximum can be set
1397 * to zero. And when that specific connector isn't active the
1398 * maximum can again be set to the appropriate non-zero value.
1399 *
1400 * If used, must be called before drm_vblank_on().
1401 */
1402void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
1403				   u32 max_vblank_count)
1404{
1405	struct drm_device *dev = crtc->dev;
1406	unsigned int pipe = drm_crtc_index(crtc);
1407	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1408
1409	drm_WARN_ON(dev, dev->max_vblank_count);
1410	drm_WARN_ON(dev, !READ_ONCE(vblank->inmodeset));
1411
1412	vblank->max_vblank_count = max_vblank_count;
1413}
1414EXPORT_SYMBOL(drm_crtc_set_max_vblank_count);
1415
1416/**
1417 * drm_crtc_vblank_on - enable vblank events on a CRTC
1418 * @crtc: CRTC in question
1419 *
1420 * This functions restores the vblank interrupt state captured with
1421 * drm_crtc_vblank_off() again and is generally called when enabling @crtc. Note
1422 * that calls to drm_crtc_vblank_on() and drm_crtc_vblank_off() can be
1423 * unbalanced and so can also be unconditionally called in driver load code to
1424 * reflect the current hardware state of the crtc.
1425 */
1426void drm_crtc_vblank_on(struct drm_crtc *crtc)
1427{
1428	struct drm_device *dev = crtc->dev;
1429	unsigned int pipe = drm_crtc_index(crtc);
1430	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1431
1432	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1433		return;
1434
1435	spin_lock_irq(&dev->vbl_lock);
1436	drm_dbg_vbl(dev, "crtc %d, vblank enabled %d, inmodeset %d\n",
1437		    pipe, vblank->enabled, vblank->inmodeset);
1438
1439	/* Drop our private "prevent drm_vblank_get" refcount */
1440	if (vblank->inmodeset) {
1441		atomic_dec(&vblank->refcount);
1442		vblank->inmodeset = 0;
1443	}
1444
1445	drm_reset_vblank_timestamp(dev, pipe);
1446
1447	/*
1448	 * re-enable interrupts if there are users left, or the
1449	 * user wishes vblank interrupts to be enabled all the time.
1450	 */
1451	if (atomic_read(&vblank->refcount) != 0 || drm_vblank_offdelay == 0)
1452		drm_WARN_ON(dev, drm_vblank_enable(dev, pipe));
1453	spin_unlock_irq(&dev->vbl_lock);
1454}
1455EXPORT_SYMBOL(drm_crtc_vblank_on);
1456
1457/**
1458 * drm_vblank_restore - estimate missed vblanks and update vblank count.
1459 * @dev: DRM device
1460 * @pipe: CRTC index
1461 *
1462 * Power manamement features can cause frame counter resets between vblank
1463 * disable and enable. Drivers can use this function in their
1464 * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblanks since
1465 * the last &drm_crtc_funcs.disable_vblank using timestamps and update the
1466 * vblank counter.
1467 *
1468 * This function is the legacy version of drm_crtc_vblank_restore().
1469 */
1470void drm_vblank_restore(struct drm_device *dev, unsigned int pipe)
1471{
1472	ktime_t t_vblank;
1473	struct drm_vblank_crtc *vblank;
1474	int framedur_ns;
1475	u64 diff_ns;
1476	u32 cur_vblank, diff = 1;
1477	int count = DRM_TIMESTAMP_MAXRETRIES;
 
1478
1479	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1480		return;
1481
1482	assert_spin_locked(&dev->vbl_lock);
1483	assert_spin_locked(&dev->vblank_time_lock);
1484
1485	vblank = &dev->vblank[pipe];
1486	drm_WARN_ONCE(dev,
1487		      drm_debug_enabled(DRM_UT_VBL) && !vblank->framedur_ns,
1488		      "Cannot compute missed vblanks without frame duration\n");
1489	framedur_ns = vblank->framedur_ns;
1490
1491	do {
1492		cur_vblank = __get_vblank_counter(dev, pipe);
1493		drm_get_last_vbltimestamp(dev, pipe, &t_vblank, false);
1494	} while (cur_vblank != __get_vblank_counter(dev, pipe) && --count > 0);
1495
1496	diff_ns = ktime_to_ns(ktime_sub(t_vblank, vblank->time));
1497	if (framedur_ns)
1498		diff = DIV_ROUND_CLOSEST_ULL(diff_ns, framedur_ns);
1499
1500
1501	drm_dbg_vbl(dev,
1502		    "missed %d vblanks in %lld ns, frame duration=%d ns, hw_diff=%d\n",
1503		    diff, diff_ns, framedur_ns, cur_vblank - vblank->last);
1504	store_vblank(dev, pipe, diff, t_vblank, cur_vblank);
1505}
1506EXPORT_SYMBOL(drm_vblank_restore);
1507
1508/**
1509 * drm_crtc_vblank_restore - estimate missed vblanks and update vblank count.
1510 * @crtc: CRTC in question
1511 *
1512 * Power manamement features can cause frame counter resets between vblank
1513 * disable and enable. Drivers can use this function in their
1514 * &drm_crtc_funcs.enable_vblank implementation to estimate missed vblanks since
1515 * the last &drm_crtc_funcs.disable_vblank using timestamps and update the
1516 * vblank counter.
 
 
 
 
 
 
1517 */
1518void drm_crtc_vblank_restore(struct drm_crtc *crtc)
1519{
 
 
 
1520	drm_vblank_restore(crtc->dev, drm_crtc_index(crtc));
1521}
1522EXPORT_SYMBOL(drm_crtc_vblank_restore);
1523
1524static void drm_legacy_vblank_pre_modeset(struct drm_device *dev,
1525					  unsigned int pipe)
1526{
1527	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1528
1529	/* vblank is not initialized (IRQ not installed ?), or has been freed */
1530	if (!drm_dev_has_vblank(dev))
1531		return;
1532
1533	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1534		return;
1535
1536	/*
1537	 * To avoid all the problems that might happen if interrupts
1538	 * were enabled/disabled around or between these calls, we just
1539	 * have the kernel take a reference on the CRTC (just once though
1540	 * to avoid corrupting the count if multiple, mismatch calls occur),
1541	 * so that interrupts remain enabled in the interim.
1542	 */
1543	if (!vblank->inmodeset) {
1544		vblank->inmodeset = 0x1;
1545		if (drm_vblank_get(dev, pipe) == 0)
1546			vblank->inmodeset |= 0x2;
1547	}
1548}
1549
1550static void drm_legacy_vblank_post_modeset(struct drm_device *dev,
1551					   unsigned int pipe)
1552{
1553	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1554
1555	/* vblank is not initialized (IRQ not installed ?), or has been freed */
1556	if (!drm_dev_has_vblank(dev))
1557		return;
1558
1559	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1560		return;
1561
1562	if (vblank->inmodeset) {
1563		spin_lock_irq(&dev->vbl_lock);
1564		drm_reset_vblank_timestamp(dev, pipe);
1565		spin_unlock_irq(&dev->vbl_lock);
1566
1567		if (vblank->inmodeset & 0x2)
1568			drm_vblank_put(dev, pipe);
1569
1570		vblank->inmodeset = 0;
1571	}
1572}
1573
1574int drm_legacy_modeset_ctl_ioctl(struct drm_device *dev, void *data,
1575				 struct drm_file *file_priv)
1576{
1577	struct drm_modeset_ctl *modeset = data;
1578	unsigned int pipe;
1579
1580	/* If drm_vblank_init() hasn't been called yet, just no-op */
1581	if (!drm_dev_has_vblank(dev))
1582		return 0;
1583
1584	/* KMS drivers handle this internally */
1585	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
1586		return 0;
1587
1588	pipe = modeset->crtc;
1589	if (pipe >= dev->num_crtcs)
1590		return -EINVAL;
1591
1592	switch (modeset->cmd) {
1593	case _DRM_PRE_MODESET:
1594		drm_legacy_vblank_pre_modeset(dev, pipe);
1595		break;
1596	case _DRM_POST_MODESET:
1597		drm_legacy_vblank_post_modeset(dev, pipe);
1598		break;
1599	default:
1600		return -EINVAL;
1601	}
1602
1603	return 0;
1604}
1605
1606static int drm_queue_vblank_event(struct drm_device *dev, unsigned int pipe,
1607				  u64 req_seq,
1608				  union drm_wait_vblank *vblwait,
1609				  struct drm_file *file_priv)
1610{
1611	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1612	struct drm_pending_vblank_event *e;
1613	ktime_t now;
1614	u64 seq;
1615	int ret;
1616
1617	e = kzalloc(sizeof(*e), GFP_KERNEL);
1618	if (e == NULL) {
1619		ret = -ENOMEM;
1620		goto err_put;
1621	}
1622
1623	e->pipe = pipe;
1624	e->event.base.type = DRM_EVENT_VBLANK;
1625	e->event.base.length = sizeof(e->event.vbl);
1626	e->event.vbl.user_data = vblwait->request.signal;
1627	e->event.vbl.crtc_id = 0;
1628	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1629		struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
1630
1631		if (crtc)
1632			e->event.vbl.crtc_id = crtc->base.id;
1633	}
1634
1635	spin_lock_irq(&dev->event_lock);
1636
1637	/*
1638	 * drm_crtc_vblank_off() might have been called after we called
1639	 * drm_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
1640	 * vblank disable, so no need for further locking.  The reference from
1641	 * drm_vblank_get() protects against vblank disable from another source.
1642	 */
1643	if (!READ_ONCE(vblank->enabled)) {
1644		ret = -EINVAL;
1645		goto err_unlock;
1646	}
1647
1648	ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
1649					    &e->event.base);
1650
1651	if (ret)
1652		goto err_unlock;
1653
1654	seq = drm_vblank_count_and_time(dev, pipe, &now);
1655
1656	drm_dbg_core(dev, "event on vblank count %llu, current %llu, crtc %u\n",
1657		     req_seq, seq, pipe);
1658
1659	trace_drm_vblank_event_queued(file_priv, pipe, req_seq);
1660
1661	e->sequence = req_seq;
1662	if (drm_vblank_passed(seq, req_seq)) {
1663		drm_vblank_put(dev, pipe);
1664		send_vblank_event(dev, e, seq, now);
1665		vblwait->reply.sequence = seq;
1666	} else {
1667		/* drm_handle_vblank_events will call drm_vblank_put */
1668		list_add_tail(&e->base.link, &dev->vblank_event_list);
1669		vblwait->reply.sequence = req_seq;
1670	}
1671
1672	spin_unlock_irq(&dev->event_lock);
1673
1674	return 0;
1675
1676err_unlock:
1677	spin_unlock_irq(&dev->event_lock);
1678	kfree(e);
1679err_put:
1680	drm_vblank_put(dev, pipe);
1681	return ret;
1682}
1683
1684static bool drm_wait_vblank_is_query(union drm_wait_vblank *vblwait)
1685{
1686	if (vblwait->request.sequence)
1687		return false;
1688
1689	return _DRM_VBLANK_RELATIVE ==
1690		(vblwait->request.type & (_DRM_VBLANK_TYPES_MASK |
1691					  _DRM_VBLANK_EVENT |
1692					  _DRM_VBLANK_NEXTONMISS));
1693}
1694
1695/*
1696 * Widen a 32-bit param to 64-bits.
1697 *
1698 * \param narrow 32-bit value (missing upper 32 bits)
1699 * \param near 64-bit value that should be 'close' to near
1700 *
1701 * This function returns a 64-bit value using the lower 32-bits from
1702 * 'narrow' and constructing the upper 32-bits so that the result is
1703 * as close as possible to 'near'.
1704 */
1705
1706static u64 widen_32_to_64(u32 narrow, u64 near)
1707{
1708	return near + (s32) (narrow - near);
1709}
1710
1711static void drm_wait_vblank_reply(struct drm_device *dev, unsigned int pipe,
1712				  struct drm_wait_vblank_reply *reply)
1713{
1714	ktime_t now;
1715	struct timespec64 ts;
1716
1717	/*
1718	 * drm_wait_vblank_reply is a UAPI structure that uses 'long'
1719	 * to store the seconds. This is safe as we always use monotonic
1720	 * timestamps since linux-4.15.
1721	 */
1722	reply->sequence = drm_vblank_count_and_time(dev, pipe, &now);
1723	ts = ktime_to_timespec64(now);
1724	reply->tval_sec = (u32)ts.tv_sec;
1725	reply->tval_usec = ts.tv_nsec / 1000;
1726}
1727
1728int drm_wait_vblank_ioctl(struct drm_device *dev, void *data,
1729			  struct drm_file *file_priv)
1730{
1731	struct drm_crtc *crtc;
1732	struct drm_vblank_crtc *vblank;
1733	union drm_wait_vblank *vblwait = data;
1734	int ret;
1735	u64 req_seq, seq;
1736	unsigned int pipe_index;
1737	unsigned int flags, pipe, high_pipe;
1738
1739	if (!dev->irq_enabled)
1740		return -EOPNOTSUPP;
1741
1742	if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
1743		return -EINVAL;
1744
1745	if (vblwait->request.type &
1746	    ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1747	      _DRM_VBLANK_HIGH_CRTC_MASK)) {
1748		drm_dbg_core(dev,
1749			     "Unsupported type value 0x%x, supported mask 0x%x\n",
1750			     vblwait->request.type,
1751			     (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
1752			      _DRM_VBLANK_HIGH_CRTC_MASK));
1753		return -EINVAL;
1754	}
1755
1756	flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
1757	high_pipe = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
1758	if (high_pipe)
1759		pipe_index = high_pipe >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
1760	else
1761		pipe_index = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
1762
1763	/* Convert lease-relative crtc index into global crtc index */
1764	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
1765		pipe = 0;
1766		drm_for_each_crtc(crtc, dev) {
1767			if (drm_lease_held(file_priv, crtc->base.id)) {
1768				if (pipe_index == 0)
1769					break;
1770				pipe_index--;
1771			}
1772			pipe++;
1773		}
1774	} else {
1775		pipe = pipe_index;
1776	}
1777
1778	if (pipe >= dev->num_crtcs)
1779		return -EINVAL;
1780
1781	vblank = &dev->vblank[pipe];
1782
1783	/* If the counter is currently enabled and accurate, short-circuit
1784	 * queries to return the cached timestamp of the last vblank.
1785	 */
1786	if (dev->vblank_disable_immediate &&
1787	    drm_wait_vblank_is_query(vblwait) &&
1788	    READ_ONCE(vblank->enabled)) {
1789		drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
1790		return 0;
1791	}
1792
1793	ret = drm_vblank_get(dev, pipe);
1794	if (ret) {
1795		drm_dbg_core(dev,
1796			     "crtc %d failed to acquire vblank counter, %d\n",
1797			     pipe, ret);
1798		return ret;
1799	}
1800	seq = drm_vblank_count(dev, pipe);
1801
1802	switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
1803	case _DRM_VBLANK_RELATIVE:
1804		req_seq = seq + vblwait->request.sequence;
1805		vblwait->request.sequence = req_seq;
1806		vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
1807		break;
1808	case _DRM_VBLANK_ABSOLUTE:
1809		req_seq = widen_32_to_64(vblwait->request.sequence, seq);
1810		break;
1811	default:
1812		ret = -EINVAL;
1813		goto done;
1814	}
1815
1816	if ((flags & _DRM_VBLANK_NEXTONMISS) &&
1817	    drm_vblank_passed(seq, req_seq)) {
1818		req_seq = seq + 1;
1819		vblwait->request.type &= ~_DRM_VBLANK_NEXTONMISS;
1820		vblwait->request.sequence = req_seq;
1821	}
1822
1823	if (flags & _DRM_VBLANK_EVENT) {
1824		/* must hold on to the vblank ref until the event fires
1825		 * drm_vblank_put will be called asynchronously
1826		 */
1827		return drm_queue_vblank_event(dev, pipe, req_seq, vblwait, file_priv);
1828	}
1829
1830	if (req_seq != seq) {
1831		int wait;
1832
1833		drm_dbg_core(dev, "waiting on vblank count %llu, crtc %u\n",
1834			     req_seq, pipe);
1835		wait = wait_event_interruptible_timeout(vblank->queue,
1836			drm_vblank_passed(drm_vblank_count(dev, pipe), req_seq) ||
1837				      !READ_ONCE(vblank->enabled),
1838			msecs_to_jiffies(3000));
1839
1840		switch (wait) {
1841		case 0:
1842			/* timeout */
1843			ret = -EBUSY;
1844			break;
1845		case -ERESTARTSYS:
1846			/* interrupted by signal */
1847			ret = -EINTR;
1848			break;
1849		default:
1850			ret = 0;
1851			break;
1852		}
1853	}
1854
1855	if (ret != -EINTR) {
1856		drm_wait_vblank_reply(dev, pipe, &vblwait->reply);
1857
1858		drm_dbg_core(dev, "crtc %d returning %u to client\n",
1859			     pipe, vblwait->reply.sequence);
1860	} else {
1861		drm_dbg_core(dev, "crtc %d vblank wait interrupted by signal\n",
1862			     pipe);
1863	}
1864
1865done:
1866	drm_vblank_put(dev, pipe);
1867	return ret;
1868}
1869
1870static void drm_handle_vblank_events(struct drm_device *dev, unsigned int pipe)
1871{
1872	struct drm_crtc *crtc = drm_crtc_from_index(dev, pipe);
1873	bool high_prec = false;
1874	struct drm_pending_vblank_event *e, *t;
1875	ktime_t now;
1876	u64 seq;
1877
1878	assert_spin_locked(&dev->event_lock);
1879
1880	seq = drm_vblank_count_and_time(dev, pipe, &now);
1881
1882	list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
1883		if (e->pipe != pipe)
1884			continue;
1885		if (!drm_vblank_passed(seq, e->sequence))
1886			continue;
1887
1888		drm_dbg_core(dev, "vblank event on %llu, current %llu\n",
1889			     e->sequence, seq);
1890
1891		list_del(&e->base.link);
1892		drm_vblank_put(dev, pipe);
1893		send_vblank_event(dev, e, seq, now);
1894	}
1895
1896	if (crtc && crtc->funcs->get_vblank_timestamp)
1897		high_prec = true;
1898
1899	trace_drm_vblank_event(pipe, seq, now, high_prec);
1900}
1901
1902/**
1903 * drm_handle_vblank - handle a vblank event
1904 * @dev: DRM device
1905 * @pipe: index of CRTC where this event occurred
1906 *
1907 * Drivers should call this routine in their vblank interrupt handlers to
1908 * update the vblank counter and send any signals that may be pending.
1909 *
1910 * This is the legacy version of drm_crtc_handle_vblank().
1911 */
1912bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe)
1913{
1914	struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
1915	unsigned long irqflags;
1916	bool disable_irq;
1917
1918	if (drm_WARN_ON_ONCE(dev, !drm_dev_has_vblank(dev)))
1919		return false;
1920
1921	if (drm_WARN_ON(dev, pipe >= dev->num_crtcs))
1922		return false;
1923
1924	spin_lock_irqsave(&dev->event_lock, irqflags);
1925
1926	/* Need timestamp lock to prevent concurrent execution with
1927	 * vblank enable/disable, as this would cause inconsistent
1928	 * or corrupted timestamps and vblank counts.
1929	 */
1930	spin_lock(&dev->vblank_time_lock);
1931
1932	/* Vblank irq handling disabled. Nothing to do. */
1933	if (!vblank->enabled) {
1934		spin_unlock(&dev->vblank_time_lock);
1935		spin_unlock_irqrestore(&dev->event_lock, irqflags);
1936		return false;
1937	}
1938
1939	drm_update_vblank_count(dev, pipe, true);
1940
1941	spin_unlock(&dev->vblank_time_lock);
1942
1943	wake_up(&vblank->queue);
1944
1945	/* With instant-off, we defer disabling the interrupt until after
1946	 * we finish processing the following vblank after all events have
1947	 * been signaled. The disable has to be last (after
1948	 * drm_handle_vblank_events) so that the timestamp is always accurate.
1949	 */
1950	disable_irq = (dev->vblank_disable_immediate &&
1951		       drm_vblank_offdelay > 0 &&
1952		       !atomic_read(&vblank->refcount));
1953
1954	drm_handle_vblank_events(dev, pipe);
1955	drm_handle_vblank_works(vblank);
1956
1957	spin_unlock_irqrestore(&dev->event_lock, irqflags);
1958
1959	if (disable_irq)
1960		vblank_disable_fn(&vblank->disable_timer);
1961
1962	return true;
1963}
1964EXPORT_SYMBOL(drm_handle_vblank);
1965
1966/**
1967 * drm_crtc_handle_vblank - handle a vblank event
1968 * @crtc: where this event occurred
1969 *
1970 * Drivers should call this routine in their vblank interrupt handlers to
1971 * update the vblank counter and send any signals that may be pending.
1972 *
1973 * This is the native KMS version of drm_handle_vblank().
1974 *
1975 * Note that for a given vblank counter value drm_crtc_handle_vblank()
1976 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
1977 * provide a barrier: Any writes done before calling
1978 * drm_crtc_handle_vblank() will be visible to callers of the later
1979 * functions, iff the vblank count is the same or a later one.
1980 *
1981 * See also &drm_vblank_crtc.count.
1982 *
1983 * Returns:
1984 * True if the event was successfully handled, false on failure.
1985 */
1986bool drm_crtc_handle_vblank(struct drm_crtc *crtc)
1987{
1988	return drm_handle_vblank(crtc->dev, drm_crtc_index(crtc));
1989}
1990EXPORT_SYMBOL(drm_crtc_handle_vblank);
1991
1992/*
1993 * Get crtc VBLANK count.
1994 *
1995 * \param dev DRM device
1996 * \param data user arguement, pointing to a drm_crtc_get_sequence structure.
1997 * \param file_priv drm file private for the user's open file descriptor
1998 */
1999
2000int drm_crtc_get_sequence_ioctl(struct drm_device *dev, void *data,
2001				struct drm_file *file_priv)
2002{
2003	struct drm_crtc *crtc;
2004	struct drm_vblank_crtc *vblank;
2005	int pipe;
2006	struct drm_crtc_get_sequence *get_seq = data;
2007	ktime_t now;
2008	bool vblank_enabled;
2009	int ret;
2010
2011	if (!drm_core_check_feature(dev, DRIVER_MODESET))
2012		return -EOPNOTSUPP;
2013
2014	if (!dev->irq_enabled)
2015		return -EOPNOTSUPP;
2016
2017	crtc = drm_crtc_find(dev, file_priv, get_seq->crtc_id);
2018	if (!crtc)
2019		return -ENOENT;
2020
2021	pipe = drm_crtc_index(crtc);
2022
2023	vblank = &dev->vblank[pipe];
2024	vblank_enabled = dev->vblank_disable_immediate && READ_ONCE(vblank->enabled);
2025
2026	if (!vblank_enabled) {
2027		ret = drm_crtc_vblank_get(crtc);
2028		if (ret) {
2029			drm_dbg_core(dev,
2030				     "crtc %d failed to acquire vblank counter, %d\n",
2031				     pipe, ret);
2032			return ret;
2033		}
2034	}
2035	drm_modeset_lock(&crtc->mutex, NULL);
2036	if (crtc->state)
2037		get_seq->active = crtc->state->enable;
2038	else
2039		get_seq->active = crtc->enabled;
2040	drm_modeset_unlock(&crtc->mutex);
2041	get_seq->sequence = drm_vblank_count_and_time(dev, pipe, &now);
2042	get_seq->sequence_ns = ktime_to_ns(now);
2043	if (!vblank_enabled)
2044		drm_crtc_vblank_put(crtc);
2045	return 0;
2046}
2047
2048/*
2049 * Queue a event for VBLANK sequence
2050 *
2051 * \param dev DRM device
2052 * \param data user arguement, pointing to a drm_crtc_queue_sequence structure.
2053 * \param file_priv drm file private for the user's open file descriptor
2054 */
2055
2056int drm_crtc_queue_sequence_ioctl(struct drm_device *dev, void *data,
2057				  struct drm_file *file_priv)
2058{
2059	struct drm_crtc *crtc;
2060	struct drm_vblank_crtc *vblank;
2061	int pipe;
2062	struct drm_crtc_queue_sequence *queue_seq = data;
2063	ktime_t now;
2064	struct drm_pending_vblank_event *e;
2065	u32 flags;
2066	u64 seq;
2067	u64 req_seq;
2068	int ret;
2069
2070	if (!drm_core_check_feature(dev, DRIVER_MODESET))
2071		return -EOPNOTSUPP;
2072
2073	if (!dev->irq_enabled)
2074		return -EOPNOTSUPP;
2075
2076	crtc = drm_crtc_find(dev, file_priv, queue_seq->crtc_id);
2077	if (!crtc)
2078		return -ENOENT;
2079
2080	flags = queue_seq->flags;
2081	/* Check valid flag bits */
2082	if (flags & ~(DRM_CRTC_SEQUENCE_RELATIVE|
2083		      DRM_CRTC_SEQUENCE_NEXT_ON_MISS))
2084		return -EINVAL;
2085
2086	pipe = drm_crtc_index(crtc);
2087
2088	vblank = &dev->vblank[pipe];
2089
2090	e = kzalloc(sizeof(*e), GFP_KERNEL);
2091	if (e == NULL)
2092		return -ENOMEM;
2093
2094	ret = drm_crtc_vblank_get(crtc);
2095	if (ret) {
2096		drm_dbg_core(dev,
2097			     "crtc %d failed to acquire vblank counter, %d\n",
2098			     pipe, ret);
2099		goto err_free;
2100	}
2101
2102	seq = drm_vblank_count_and_time(dev, pipe, &now);
2103	req_seq = queue_seq->sequence;
2104
2105	if (flags & DRM_CRTC_SEQUENCE_RELATIVE)
2106		req_seq += seq;
2107
2108	if ((flags & DRM_CRTC_SEQUENCE_NEXT_ON_MISS) && drm_vblank_passed(seq, req_seq))
2109		req_seq = seq + 1;
2110
2111	e->pipe = pipe;
2112	e->event.base.type = DRM_EVENT_CRTC_SEQUENCE;
2113	e->event.base.length = sizeof(e->event.seq);
2114	e->event.seq.user_data = queue_seq->user_data;
2115
2116	spin_lock_irq(&dev->event_lock);
2117
2118	/*
2119	 * drm_crtc_vblank_off() might have been called after we called
2120	 * drm_crtc_vblank_get(). drm_crtc_vblank_off() holds event_lock around the
2121	 * vblank disable, so no need for further locking.  The reference from
2122	 * drm_crtc_vblank_get() protects against vblank disable from another source.
2123	 */
2124	if (!READ_ONCE(vblank->enabled)) {
2125		ret = -EINVAL;
2126		goto err_unlock;
2127	}
2128
2129	ret = drm_event_reserve_init_locked(dev, file_priv, &e->base,
2130					    &e->event.base);
2131
2132	if (ret)
2133		goto err_unlock;
2134
2135	e->sequence = req_seq;
2136
2137	if (drm_vblank_passed(seq, req_seq)) {
2138		drm_crtc_vblank_put(crtc);
2139		send_vblank_event(dev, e, seq, now);
2140		queue_seq->sequence = seq;
2141	} else {
2142		/* drm_handle_vblank_events will call drm_vblank_put */
2143		list_add_tail(&e->base.link, &dev->vblank_event_list);
2144		queue_seq->sequence = req_seq;
2145	}
2146
2147	spin_unlock_irq(&dev->event_lock);
2148	return 0;
2149
2150err_unlock:
2151	spin_unlock_irq(&dev->event_lock);
2152	drm_crtc_vblank_put(crtc);
2153err_free:
2154	kfree(e);
2155	return ret;
2156}
2157