- 根目录:
- drivers
- gpu
- drm
- drm_irq.c
/**
* \file drm_irq.c
* IRQ support
*
* \author Rickard E. (Rik) Faith <faith@valinux.com>
* \author Gareth Hughes <gareth@valinux.com>
*/
/*
* Created: Fri Mar 19 14:30:16 1999 by faith@valinux.com
*
* Copyright 1999, 2000 Precision Insight, Inc., Cedar Park, Texas.
* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include "drmP.h"
#include "drm_trace.h"
#include <linux/interrupt.h> /* For task queue support */
#include <linux/slab.h>
#include <linux/vgaarb.h>
/* Access macro for slots in vblank timestamp ringbuffer. */
#define vblanktimestamp(dev, crtc, count) ( \
(dev)->_vblank_time[(crtc) * DRM_VBLANKTIME_RBSIZE + \
((count) % DRM_VBLANKTIME_RBSIZE)])
/* Retry timestamp calculation up to 3 times to satisfy
* drm_timestamp_precision before giving up.
*/
#define DRM_TIMESTAMP_MAXRETRIES 3
/* Threshold in nanoseconds for detection of redundant
* vblank irq in drm_handle_vblank(). 1 msec should be ok.
*/
#define DRM_REDUNDANT_VBLIRQ_THRESH_NS 1000000
/**
* Get interrupt from bus id.
*
* \param inode device inode.
* \param file_priv DRM file private.
* \param cmd command.
* \param arg user argument, pointing to a drm_irq_busid structure.
* \return zero on success or a negative number on failure.
*
* Finds the PCI device with the specified bus id and gets its IRQ number.
* This IOCTL is deprecated, and will now return EINVAL for any busid not equal
* to that of the device that this DRM instance attached to.
*/
int drm_irq_by_busid(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_irq_busid *p = data;
if (!dev->driver->bus->irq_by_busid)
return -EINVAL;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
return dev->driver->bus->irq_by_busid(dev, p);
}
/*
* Clear vblank timestamp buffer for a crtc.
*/
static void clear_vblank_timestamps(struct drm_device *dev, int crtc)
{
memset(&dev->_vblank_time[crtc * DRM_VBLANKTIME_RBSIZE], 0,
DRM_VBLANKTIME_RBSIZE * sizeof(struct timeval));
}
/*
* Disable vblank irq's on crtc, make sure that last vblank count
* of hardware and corresponding consistent software vblank counter
* are preserved, even if there are any spurious vblank irq's after
* disable.
*/
static void vblank_disable_and_save(struct drm_device *dev, int crtc)
{
unsigned long irqflags;
u32 vblcount;
s64 diff_ns;
int vblrc;
struct timeval tvblank;
/* Prevent vblank irq processing while disabling vblank irqs,
* so no updates of timestamps or count can happen after we've
* disabled. Needed to prevent races in case of delayed irq's.
* Disable preemption, so vblank_time_lock is held as short as
* possible, even under a kernel with PREEMPT_RT patches.
*/
preempt_disable();
spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
dev->driver->disable_vblank(dev, crtc);
dev->vblank_enabled[crtc] = 0;
/* No further vblank irq's will be processed after
* this point. Get current hardware vblank count and
* vblank timestamp, repeat until they are consistent.
*
* FIXME: There is still a race condition here and in
* drm_update_vblank_count() which can cause off-by-one
* reinitialization of software vblank counter. If gpu
* vblank counter doesn't increment exactly at the leading
* edge of a vblank interval, then we can lose 1 count if
* we happen to execute between start of vblank and the
* delayed gpu counter increment.
*/
do {
dev->last_vblank[crtc] = dev->driver->get_vblank_counter(dev, crtc);
vblrc = drm_get_last_vbltimestamp(dev, crtc, &tvblank, 0);
} while (dev->last_vblank[crtc] != dev->driver->get_vblank_counter(dev, crtc));
/* Compute time difference to stored timestamp of last vblank
* as updated by last invocation of drm_handle_vblank() in vblank irq.
*/
vblcount = atomic_read(&dev->_vblank_count[crtc]);
diff_ns = timeval_to_ns(&tvblank) -
timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
/* If there is at least 1 msec difference between the last stored
* timestamp and tvblank, then we are currently executing our
* disable inside a new vblank interval, the tvblank timestamp
* corresponds to this new vblank interval and the irq handler
* for this vblank didn't run yet and won't run due to our disable.
* Therefore we need to do the job of drm_handle_vblank() and
* increment the vblank counter by one to account for this vblank.
*
* Skip this step if there isn't any high precision timestamp
* available. In that case we can't account for this and just
* hope for the best.
*/
if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) {
atomic_inc(&dev->_vblank_count[crtc]);
smp_mb__after_atomic_inc();
}
/* Invalidate all timestamps while vblank irq's are off. */
clear_vblank_timestamps(dev, crtc);
spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
preempt_enable();
}
static void vblank_disable_fn(unsigned long arg)
{
struct drm_device *dev = (struct drm_device *)arg;
unsigned long irqflags;
int i;
if (!dev->vblank_disable_allowed)
return;
for (i = 0; i < dev->num_crtcs; i++) {
spin_lock_irqsave(&dev->vbl_lock, irqflags);
if (atomic_read(&dev->vblank_refcount[i]) == 0 &&
dev->vblank_enabled[i]) {
DRM_DEBUG("disabling vblank on crtc %d\n", i);
vblank_disable_and_save(dev, i);
}
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
}
void drm_vblank_cleanup(struct drm_device *dev)
{
/* Bail if the driver didn't call drm_vblank_init() */
if (dev->num_crtcs == 0)
return;
del_timer(&dev->vblank_disable_timer);
vblank_disable_fn((unsigned long)dev);
kfree(dev->vbl_queue);
kfree(dev->_vblank_count);
kfree(dev->vblank_refcount);
kfree(dev->vblank_enabled);
kfree(dev->last_vblank);
kfree(dev->last_vblank_wait);
kfree(dev->vblank_inmodeset);
kfree(dev->_vblank_time);
dev->num_crtcs = 0;
}
EXPORT_SYMBOL(drm_vblank_cleanup);
int drm_vblank_init(struct drm_device *dev, int num_crtcs)
{
int i, ret = -ENOMEM;
setup_timer(&dev->vblank_disable_timer, vblank_disable_fn,
(unsigned long)dev);
spin_lock_init(&dev->vbl_lock);
spin_lock_init(&dev->vblank_time_lock);
dev->num_crtcs = num_crtcs;
dev->vbl_queue = kmalloc(sizeof(wait_queue_head_t) * num_crtcs,
GFP_KERNEL);
if (!dev->vbl_queue)
goto err;
dev->_vblank_count = kmalloc(sizeof(atomic_t) * num_crtcs, GFP_KERNEL);
if (!dev->_vblank_count)
goto err;
dev->vblank_refcount = kmalloc(sizeof(atomic_t) * num_crtcs,
GFP_KERNEL);
if (!dev->vblank_refcount)
goto err;
dev->vblank_enabled = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
if (!dev->vblank_enabled)
goto err;
dev->last_vblank = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
if (!dev->last_vblank)
goto err;
dev->last_vblank_wait = kcalloc(num_crtcs, sizeof(u32), GFP_KERNEL);
if (!dev->last_vblank_wait)
goto err;
dev->vblank_inmodeset = kcalloc(num_crtcs, sizeof(int), GFP_KERNEL);
if (!dev->vblank_inmodeset)
goto err;
dev->_vblank_time = kcalloc(num_crtcs * DRM_VBLANKTIME_RBSIZE,
sizeof(struct timeval), GFP_KERNEL);
if (!dev->_vblank_time)
goto err;
DRM_INFO("Supports vblank timestamp caching Rev 1 (10.10.2010).\n");
/* Driver specific high-precision vblank timestamping supported? */
if (dev->driver->get_vblank_timestamp)
DRM_INFO("Driver supports precise vblank timestamp query.\n");
else
DRM_INFO("No driver support for vblank timestamp query.\n");
/* Zero per-crtc vblank stuff */
for (i = 0; i < num_crtcs; i++) {
init_waitqueue_head(&dev->vbl_queue[i]);
atomic_set(&dev->_vblank_count[i], 0);
atomic_set(&dev->vblank_refcount[i], 0);
}
dev->vblank_disable_allowed = 0;
return 0;
err:
drm_vblank_cleanup(dev);
return ret;
}
EXPORT_SYMBOL(drm_vblank_init);
static void drm_irq_vgaarb_nokms(void *cookie, bool state)
{
struct drm_device *dev = cookie;
if (dev->driver->vgaarb_irq) {
dev->driver->vgaarb_irq(dev, state);
return;
}
if (!dev->irq_enabled)
return;
if (state)
dev->driver->irq_uninstall(dev);
else {
dev->driver->irq_preinstall(dev);
dev->driver->irq_postinstall(dev);
}
}
/**
* Install IRQ handler.
*
* \param dev DRM device.
*
* Initializes the IRQ related data. Installs the handler, calling the driver
* \c drm_driver_irq_preinstall() and \c drm_driver_irq_postinstall() functions
* before and after the installation.
*/
int drm_irq_install(struct drm_device *dev)
{
int ret = 0;
unsigned long sh_flags = 0;
char *irqname;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
if (drm_dev_to_irq(dev) == 0)
return -EINVAL;
mutex_lock(&dev->struct_mutex);
/* Driver must have been initialized */
if (!dev->dev_private) {
mutex_unlock(&dev->struct_mutex);
return -EINVAL;
}
if (dev->irq_enabled) {
mutex_unlock(&dev->struct_mutex);
return -EBUSY;
}
dev->irq_enabled = 1;
mutex_unlock(&dev->struct_mutex);
DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
/* Before installing handler */
dev->driver->irq_preinstall(dev);
/* Install handler */
if (drm_core_check_feature(dev, DRIVER_IRQ_SHARED))
sh_flags = IRQF_SHARED;
if (dev->devname)
irqname = dev->devname;
else
irqname = dev->driver->name;
ret = request_irq(drm_dev_to_irq(dev), dev->driver->irq_handler,
sh_flags, irqname, dev);
if (ret < 0) {
mutex_lock(&dev->struct_mutex);
dev->irq_enabled = 0;
mutex_unlock(&dev->struct_mutex);
return ret;
}
if (!drm_core_check_feature(dev, DRIVER_MODESET))
vga_client_register(dev->pdev, (void *)dev, drm_irq_vgaarb_nokms, NULL);
/* After installing handler */
ret = dev->driver->irq_postinstall(dev);
if (ret < 0) {
mutex_lock(&dev->struct_mutex);
dev->irq_enabled = 0;
mutex_unlock(&dev->struct_mutex);
}
return ret;
}
EXPORT_SYMBOL(drm_irq_install);
/**
* Uninstall the IRQ handler.
*
* \param dev DRM device.
*
* Calls the driver's \c drm_driver_irq_uninstall() function, and stops the irq.
*/
int drm_irq_uninstall(struct drm_device *dev)
{
unsigned long irqflags;
int irq_enabled, i;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
mutex_lock(&dev->struct_mutex);
irq_enabled = dev->irq_enabled;
dev->irq_enabled = 0;
mutex_unlock(&dev->struct_mutex);
/*
* Wake up any waiters so they don't hang.
*/
spin_lock_irqsave(&dev->vbl_lock, irqflags);
for (i = 0; i < dev->num_crtcs; i++) {
DRM_WAKEUP(&dev->vbl_queue[i]);
dev->vblank_enabled[i] = 0;
dev->last_vblank[i] = dev->driver->get_vblank_counter(dev, i);
}
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
if (!irq_enabled)
return -EINVAL;
DRM_DEBUG("irq=%d\n", drm_dev_to_irq(dev));
if (!drm_core_check_feature(dev, DRIVER_MODESET))
vga_client_register(dev->pdev, NULL, NULL, NULL);
dev->driver->irq_uninstall(dev);
free_irq(drm_dev_to_irq(dev), dev);
return 0;
}
EXPORT_SYMBOL(drm_irq_uninstall);
/**
* IRQ control ioctl.
*
* \param inode device inode.
* \param file_priv DRM file private.
* \param cmd command.
* \param arg user argument, pointing to a drm_control structure.
* \return zero on success or a negative number on failure.
*
* Calls irq_install() or irq_uninstall() according to \p arg.
*/
int drm_control(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_control *ctl = data;
/* if we haven't irq we fallback for compatibility reasons -
* this used to be a separate function in drm_dma.h
*/
switch (ctl->func) {
case DRM_INST_HANDLER:
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return 0;
if (drm_core_check_feature(dev, DRIVER_MODESET))
return 0;
if (dev->if_version < DRM_IF_VERSION(1, 2) &&
ctl->irq != drm_dev_to_irq(dev))
return -EINVAL;
return drm_irq_install(dev);
case DRM_UNINST_HANDLER:
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return 0;
if (drm_core_check_feature(dev, DRIVER_MODESET))
return 0;
return drm_irq_uninstall(dev);
default:
return -EINVAL;
}
}
/**
* drm_calc_timestamping_constants - Calculate and
* store various constants which are later needed by
* vblank and swap-completion timestamping, e.g, by
* drm_calc_vbltimestamp_from_scanoutpos().
* They are derived from crtc's true scanout timing,
* so they take things like panel scaling or other
* adjustments into account.
*
* @crtc drm_crtc whose timestamp constants should be updated.
*
*/
void drm_calc_timestamping_constants(struct drm_crtc *crtc)
{
s64 linedur_ns = 0, pixeldur_ns = 0, framedur_ns = 0;
u64 dotclock;
/* Dot clock in Hz: */
dotclock = (u64) crtc->hwmode.clock * 1000;
/* Fields of interlaced scanout modes are only halve a frame duration.
* Double the dotclock to get halve the frame-/line-/pixelduration.
*/
if (crtc->hwmode.flags & DRM_MODE_FLAG_INTERLACE)
dotclock *= 2;
/* Valid dotclock? */
if (dotclock > 0) {
/* Convert scanline length in pixels and video dot clock to
* line duration, frame duration and pixel duration in
* nanoseconds:
*/
pixeldur_ns = (s64) div64_u64(1000000000, dotclock);
linedur_ns = (s64) div64_u64(((u64) crtc->hwmode.crtc_htotal *
1000000000), dotclock);
framedur_ns = (s64) crtc->hwmode.crtc_vtotal * linedur_ns;
} else
DRM_ERROR("crtc %d: Can't calculate constants, dotclock = 0!\n",
crtc->base.id);
crtc->pixeldur_ns = pixeldur_ns;
crtc->linedur_ns = linedur_ns;
crtc->framedur_ns = framedur_ns;
DRM_DEBUG("crtc %d: hwmode: htotal %d, vtotal %d, vdisplay %d\n",
crtc->base.id, crtc->hwmode.crtc_htotal,
crtc->hwmode.crtc_vtotal, crtc->hwmode.crtc_vdisplay);
DRM_DEBUG("crtc %d: clock %d kHz framedur %d linedur %d, pixeldur %d\n",
crtc->base.id, (int) dotclock/1000, (int) framedur_ns,
(int) linedur_ns, (int) pixeldur_ns);
}
EXPORT_SYMBOL(drm_calc_timestamping_constants);
/**
* drm_calc_vbltimestamp_from_scanoutpos - helper routine for kms
* drivers. Implements calculation of exact vblank timestamps from
* given drm_display_mode timings and current video scanout position
* of a crtc. This can be called from within get_vblank_timestamp()
* implementation of a kms driver to implement the actual timestamping.
*
* Should return timestamps conforming to the OML_sync_control OpenML
* extension specification. The timestamp corresponds to the end of
* the vblank interval, aka start of scanout of topmost-leftmost display
* pixel in the following video frame.
*
* Requires support for optional dev->driver->get_scanout_position()
* in kms driver, plus a bit of setup code to provide a drm_display_mode
* that corresponds to the true scanout timing.
*
* The current implementation only handles standard video modes. It
* returns as no operation if a doublescan or interlaced video mode is
* active. Higher level code is expected to handle this.
*
* @dev: DRM device.
* @crtc: Which crtc's vblank timestamp to retrieve.
* @max_error: Desired maximum allowable error in timestamps (nanosecs).
* On return contains true maximum error of timestamp.
* @vblank_time: Pointer to struct timeval which should receive the timestamp.
* @flags: Flags to pass to driver:
* 0 = Default.
* DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
* @refcrtc: drm_crtc* of crtc which defines scanout timing.
*
* Returns negative value on error, failure or if not supported in current
* video mode:
*
* -EINVAL - Invalid crtc.
* -EAGAIN - Temporary unavailable, e.g., called before initial modeset.
* -ENOTSUPP - Function not supported in current display mode.
* -EIO - Failed, e.g., due to failed scanout position query.
*
* Returns or'ed positive status flags on success:
*
* DRM_VBLANKTIME_SCANOUTPOS_METHOD - Signal this method used for timestamping.
* DRM_VBLANKTIME_INVBL - Timestamp taken while scanout was in vblank interval.
*
*/
int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
int *max_error,
struct timeval *vblank_time,
unsigned flags,
struct drm_crtc *refcrtc)
{
struct timeval stime, raw_time;
struct drm_display_mode *mode;
int vbl_status, vtotal, vdisplay;
int vpos, hpos, i;
s64 framedur_ns, linedur_ns, pixeldur_ns, delta_ns, duration_ns;
bool invbl;
if (crtc < 0 || crtc >= dev->num_crtcs) {
DRM_ERROR("Invalid crtc %d\n", crtc);
return -EINVAL;
}
/* Scanout position query not supported? Should not happen. */
if (!dev->driver->get_scanout_position) {
DRM_ERROR("Called from driver w/o get_scanout_position()!?\n");
return -EIO;
}
mode = &refcrtc->hwmode;
vtotal = mode->crtc_vtotal;
vdisplay = mode->crtc_vdisplay;
/* Durations of frames, lines, pixels in nanoseconds. */
framedur_ns = refcrtc->framedur_ns;
linedur_ns = refcrtc->linedur_ns;
pixeldur_ns = refcrtc->pixeldur_ns;
/* If mode timing undefined, just return as no-op:
* Happens during initial modesetting of a crtc.
*/
if (vtotal <= 0 || vdisplay <= 0 || framedur_ns == 0) {
DRM_DEBUG("crtc %d: Noop due to uninitialized mode.\n", crtc);
return -EAGAIN;
}
/* Get current scanout position with system timestamp.
* Repeat query up to DRM_TIMESTAMP_MAXRETRIES times
* if single query takes longer than max_error nanoseconds.
*
* This guarantees a tight bound on maximum error if
* code gets preempted or delayed for some reason.
*/
for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
/* Disable preemption to make it very likely to
* succeed in the first iteration even on PREEMPT_RT kernel.
*/
preempt_disable();
/* Get system timestamp before query. */
do_gettimeofday(&stime);
/* Get vertical and horizontal scanout pos. vpos, hpos. */
vbl_status = dev->driver->get_scanout_position(dev, crtc, &vpos, &hpos);
/* Get system timestamp after query. */
do_gettimeofday(&raw_time);
preempt_enable();
/* Return as no-op if scanout query unsupported or failed. */
if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
crtc, vbl_status);
return -EIO;
}
duration_ns = timeval_to_ns(&raw_time) - timeval_to_ns(&stime);
/* Accept result with < max_error nsecs timing uncertainty. */
if (duration_ns <= (s64) *max_error)
break;
}
/* Noisy system timing? */
if (i == DRM_TIMESTAMP_MAXRETRIES) {
DRM_DEBUG("crtc %d: Noisy timestamp %d us > %d us [%d reps].\n",
crtc, (int) duration_ns/1000, *max_error/1000, i);
}
/* Return upper bound of timestamp precision error. */
*max_error = (int) duration_ns;
/* Check if in vblank area:
* vpos is >=0 in video scanout area, but negative
* within vblank area, counting down the number of lines until
* start of scanout.
*/
invbl = vbl_status & DRM_SCANOUTPOS_INVBL;
/* Convert scanout position into elapsed time at raw_time query
* since start of scanout at first display scanline. delta_ns
* can be negative if start of scanout hasn't happened yet.
*/
delta_ns = (s64) vpos * linedur_ns + (s64) hpos * pixeldur_ns;
/* Is vpos outside nominal vblank area, but less than
* 1/100 of a frame height away from start of vblank?
* If so, assume this isn't a massively delayed vblank
* interrupt, but a vblank interrupt that fired a few
* microseconds before true start of vblank. Compensate
* by adding a full frame duration to the final timestamp.
* Happens, e.g., on ATI R500, R600.
*
* We only do this if DRM_CALLED_FROM_VBLIRQ.
*/
if ((flags & DRM_CALLED_FROM_VBLIRQ) && !invbl &&
((vdisplay - vpos) < vtotal / 100)) {
delta_ns = delta_ns - framedur_ns;
/* Signal this correction as "applied". */
vbl_status |= 0x8;
}
/* Subtract time delta from raw timestamp to get final
* vblank_time timestamp for end of vblank.
*/
*vblank_time = ns_to_timeval(timeval_to_ns(&raw_time) - delta_ns);
DRM_DEBUG("crtc %d : v %d p(%d,%d)@ %d.%d -> %d.%d [e %d us, %d rep]\n",
crtc, (int) vbl_status, hpos, vpos, raw_time.tv_sec,
raw_time.tv_usec, vblank_time->tv_sec, vblank_time->tv_usec,
(int) duration_ns/1000, i);
vbl_status = DRM_VBLANKTIME_SCANOUTPOS_METHOD;
if (invbl)
vbl_status |= DRM_VBLANKTIME_INVBL;
return vbl_status;
}
EXPORT_SYMBOL(drm_calc_vbltimestamp_from_scanoutpos);
/**
* drm_get_last_vbltimestamp - retrieve raw timestamp for the most recent
* vblank interval.
*
* @dev: DRM device
* @crtc: which crtc's vblank timestamp to retrieve
* @tvblank: Pointer to target struct timeval which should receive the timestamp
* @flags: Flags to pass to driver:
* 0 = Default.
* DRM_CALLED_FROM_VBLIRQ = If function is called from vbl irq handler.
*
* Fetches the system timestamp corresponding to the time of the most recent
* vblank interval on specified crtc. May call into kms-driver to
* compute the timestamp with a high-precision GPU specific method.
*
* Returns zero if timestamp originates from uncorrected do_gettimeofday()
* call, i.e., it isn't very precisely locked to the true vblank.
*
* Returns non-zero if timestamp is considered to be very precise.
*/
u32 drm_get_last_vbltimestamp(struct drm_device *dev, int crtc,
struct timeval *tvblank, unsigned flags)
{
int ret = 0;
/* Define requested maximum error on timestamps (nanoseconds). */
int max_error = (int) drm_timestamp_precision * 1000;
/* Query driver if possible and precision timestamping enabled. */
if (dev->driver->get_vblank_timestamp && (max_error > 0)) {
ret = dev->driver->get_vblank_timestamp(dev, crtc, &max_error,
tvblank, flags);
if (ret > 0)
return (u32) ret;
}
/* GPU high precision timestamp query unsupported or failed.
* Return gettimeofday timestamp as best estimate.
*/
do_gettimeofday(tvblank);
return 0;
}
EXPORT_SYMBOL(drm_get_last_vbltimestamp);
/**
* drm_vblank_count - retrieve "cooked" vblank counter value
* @dev: DRM device
* @crtc: which counter to retrieve
*
* Fetches the "cooked" vblank count value that represents the number of
* vblank events since the system was booted, including lost events due to
* modesetting activity.
*/
u32 drm_vblank_count(struct drm_device *dev, int crtc)
{
return atomic_read(&dev->_vblank_count[crtc]);
}
EXPORT_SYMBOL(drm_vblank_count);
/**
* drm_vblank_count_and_time - retrieve "cooked" vblank counter value
* and the system timestamp corresponding to that vblank counter value.
*
* @dev: DRM device
* @crtc: which counter to retrieve
* @vblanktime: Pointer to struct timeval to receive the vblank timestamp.
*
* Fetches the "cooked" vblank count value that represents the number of
* vblank events since the system was booted, including lost events due to
* modesetting activity. Returns corresponding system timestamp of the time
* of the vblank interval that corresponds to the current value vblank counter
* value.
*/
u32 drm_vblank_count_and_time(struct drm_device *dev, int crtc,
struct timeval *vblanktime)
{
u32 cur_vblank;
/* Read timestamp from slot of _vblank_time ringbuffer
* that corresponds to current vblank count. Retry if
* count has incremented during readout. This works like
* a seqlock.
*/
do {
cur_vblank = atomic_read(&dev->_vblank_count[crtc]);
*vblanktime = vblanktimestamp(dev, crtc, cur_vblank);
smp_rmb();
} while (cur_vblank != atomic_read(&dev->_vblank_count[crtc]));
return cur_vblank;
}
EXPORT_SYMBOL(drm_vblank_count_and_time);
/**
* drm_update_vblank_count - update the master vblank counter
* @dev: DRM device
* @crtc: counter to update
*
* Call back into the driver to update the appropriate vblank counter
* (specified by @crtc). Deal with wraparound, if it occurred, and
* update the last read value so we can deal with wraparound on the next
* call if necessary.
*
* Only necessary when going from off->on, to account for frames we
* didn't get an interrupt for.
*
* Note: caller must hold dev->vbl_lock since this reads & writes
* device vblank fields.
*/
static void drm_update_vblank_count(struct drm_device *dev, int crtc)
{
u32 cur_vblank, diff, tslot, rc;
struct timeval t_vblank;
/*
* Interrupts were disabled prior to this call, so deal with counter
* wrap if needed.
* NOTE! It's possible we lost a full dev->max_vblank_count events
* here if the register is small or we had vblank interrupts off for
* a long time.
*
* We repeat the hardware vblank counter & timestamp query until
* we get consistent results. This to prevent races between gpu
* updating its hardware counter while we are retrieving the
* corresponding vblank timestamp.
*/
do {
cur_vblank = dev->driver->get_vblank_counter(dev, crtc);
rc = drm_get_last_vbltimestamp(dev, crtc, &t_vblank, 0);
} while (cur_vblank != dev->driver->get_vblank_counter(dev, crtc));
/* Deal with counter wrap */
diff = cur_vblank - dev->last_vblank[crtc];
if (cur_vblank < dev->last_vblank[crtc]) {
diff += dev->max_vblank_count;
DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n",
crtc, dev->last_vblank[crtc], cur_vblank, diff);
}
DRM_DEBUG("enabling vblank interrupts on crtc %d, missed %d\n",
crtc, diff);
/* Reinitialize corresponding vblank timestamp if high-precision query
* available. Skip this step if query unsupported or failed. Will
* reinitialize delayed at next vblank interrupt in that case.
*/
if (rc) {
tslot = atomic_read(&dev->_vblank_count[crtc]) + diff;
vblanktimestamp(dev, crtc, tslot) = t_vblank;
}
smp_mb__before_atomic_inc();
atomic_add(diff, &dev->_vblank_count[crtc]);
smp_mb__after_atomic_inc();
}
/**
* drm_vblank_get - get a reference count on vblank events
* @dev: DRM device
* @crtc: which CRTC to own
*
* Acquire a reference count on vblank events to avoid having them disabled
* while in use.
*
* RETURNS
* Zero on success, nonzero on failure.
*/
int drm_vblank_get(struct drm_device *dev, int crtc)
{
unsigned long irqflags, irqflags2;
int ret = 0;
spin_lock_irqsave(&dev->vbl_lock, irqflags);
/* Going from 0->1 means we have to enable interrupts again */
if (atomic_add_return(1, &dev->vblank_refcount[crtc]) == 1) {
/* Disable preemption while holding vblank_time_lock. Do
* it explicitely to guard against PREEMPT_RT kernel.
*/
preempt_disable();
spin_lock_irqsave(&dev->vblank_time_lock, irqflags2);
if (!dev->vblank_enabled[crtc]) {
/* Enable vblank irqs under vblank_time_lock protection.
* All vblank count & timestamp updates are held off
* until we are done reinitializing master counter and
* timestamps. Filtercode in drm_handle_vblank() will
* prevent double-accounting of same vblank interval.
*/
ret = dev->driver->enable_vblank(dev, crtc);
DRM_DEBUG("enabling vblank on crtc %d, ret: %d\n",
crtc, ret);
if (ret)
atomic_dec(&dev->vblank_refcount[crtc]);
else {
dev->vblank_enabled[crtc] = 1;
drm_update_vblank_count(dev, crtc);
}
}
spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags2);
preempt_enable();
} else {
if (!dev->vblank_enabled[crtc]) {
atomic_dec(&dev->vblank_refcount[crtc]);
ret = -EINVAL;
}
}
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
return ret;
}
EXPORT_SYMBOL(drm_vblank_get);
/**
* drm_vblank_put - give up ownership of vblank events
* @dev: DRM device
* @crtc: which counter to give up
*
* Release ownership of a given vblank counter, turning off interrupts
* if possible. Disable interrupts after drm_vblank_offdelay milliseconds.
*/
void drm_vblank_put(struct drm_device *dev, int crtc)
{
BUG_ON(atomic_read(&dev->vblank_refcount[crtc]) == 0);
/* Last user schedules interrupt disable */
if (atomic_dec_and_test(&dev->vblank_refcount[crtc]) &&
(drm_vblank_offdelay > 0))
mod_timer(&dev->vblank_disable_timer,
jiffies + ((drm_vblank_offdelay * DRM_HZ)/1000));
}
EXPORT_SYMBOL(drm_vblank_put);
void drm_vblank_off(struct drm_device *dev, int crtc)
{
struct drm_pending_vblank_event *e, *t;
struct timeval now;
unsigned long irqflags;
unsigned int seq;
spin_lock_irqsave(&dev->vbl_lock, irqflags);
vblank_disable_and_save(dev, crtc);
DRM_WAKEUP(&dev->vbl_queue[crtc]);
/* Send any queued vblank events, lest the natives grow disquiet */
seq = drm_vblank_count_and_time(dev, crtc, &now);
list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
if (e->pipe != crtc)
continue;
DRM_DEBUG("Sending premature vblank event on disable: \
wanted %d, current %d\n",
e->event.sequence, seq);
e->event.sequence = seq;
e->event.tv_sec = now.tv_sec;
e->event.tv_usec = now.tv_usec;
drm_vblank_put(dev, e->pipe);
list_move_tail(&e->base.link, &e->base.file_priv->event_list);
wake_up_interruptible(&e->base.file_priv->event_wait);
trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
e->event.sequence);
}
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
EXPORT_SYMBOL(drm_vblank_off);
/**
* drm_vblank_pre_modeset - account for vblanks across mode sets
* @dev: DRM device
* @crtc: CRTC in question
* @post: post or pre mode set?
*
* Account for vblank events across mode setting events, which will likely
* reset the hardware frame counter.
*/
void drm_vblank_pre_modeset(struct drm_device *dev, int crtc)
{
/* vblank is not initialized (IRQ not installed ?) */
if (!dev->num_crtcs)
return;
/*
* To avoid all the problems that might happen if interrupts
* were enabled/disabled around or between these calls, we just
* have the kernel take a reference on the CRTC (just once though
* to avoid corrupting the count if multiple, mismatch calls occur),
* so that interrupts remain enabled in the interim.
*/
if (!dev->vblank_inmodeset[crtc]) {
dev->vblank_inmodeset[crtc] = 0x1;
if (drm_vblank_get(dev, crtc) == 0)
dev->vblank_inmodeset[crtc] |= 0x2;
}
}
EXPORT_SYMBOL(drm_vblank_pre_modeset);
void drm_vblank_post_modeset(struct drm_device *dev, int crtc)
{
unsigned long irqflags;
if (dev->vblank_inmodeset[crtc]) {
spin_lock_irqsave(&dev->vbl_lock, irqflags);
dev->vblank_disable_allowed = 1;
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
if (dev->vblank_inmodeset[crtc] & 0x2)
drm_vblank_put(dev, crtc);
dev->vblank_inmodeset[crtc] = 0;
}
}
EXPORT_SYMBOL(drm_vblank_post_modeset);
/**
* drm_modeset_ctl - handle vblank event counter changes across mode switch
* @DRM_IOCTL_ARGS: standard ioctl arguments
*
* Applications should call the %_DRM_PRE_MODESET and %_DRM_POST_MODESET
* ioctls around modesetting so that any lost vblank events are accounted for.
*
* Generally the counter will reset across mode sets. If interrupts are
* enabled around this call, we don't have to do anything since the counter
* will have already been incremented.
*/
int drm_modeset_ctl(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
struct drm_modeset_ctl *modeset = data;
int ret = 0;
unsigned int crtc;
/* If drm_vblank_init() hasn't been called yet, just no-op */
if (!dev->num_crtcs)
goto out;
crtc = modeset->crtc;
if (crtc >= dev->num_crtcs) {
ret = -EINVAL;
goto out;
}
switch (modeset->cmd) {
case _DRM_PRE_MODESET:
drm_vblank_pre_modeset(dev, crtc);
break;
case _DRM_POST_MODESET:
drm_vblank_post_modeset(dev, crtc);
break;
default:
ret = -EINVAL;
break;
}
out:
return ret;
}
static int drm_queue_vblank_event(struct drm_device *dev, int pipe,
union drm_wait_vblank *vblwait,
struct drm_file *file_priv)
{
struct drm_pending_vblank_event *e;
struct timeval now;
unsigned long flags;
unsigned int seq;
int ret;
e = kzalloc(sizeof *e, GFP_KERNEL);
if (e == NULL) {
ret = -ENOMEM;
goto err_put;
}
e->pipe = pipe;
e->base.pid = current->pid;
e->event.base.type = DRM_EVENT_VBLANK;
e->event.base.length = sizeof e->event;
e->event.user_data = vblwait->request.signal;
e->base.event = &e->event.base;
e->base.file_priv = file_priv;
e->base.destroy = (void (*) (struct drm_pending_event *)) kfree;
spin_lock_irqsave(&dev->event_lock, flags);
if (file_priv->event_space < sizeof e->event) {
ret = -EBUSY;
goto err_unlock;
}
file_priv->event_space -= sizeof e->event;
seq = drm_vblank_count_and_time(dev, pipe, &now);
if ((vblwait->request.type & _DRM_VBLANK_NEXTONMISS) &&
(seq - vblwait->request.sequence) <= (1 << 23)) {
vblwait->request.sequence = seq + 1;
vblwait->reply.sequence = vblwait->request.sequence;
}
DRM_DEBUG("event on vblank count %d, current %d, crtc %d\n",
vblwait->request.sequence, seq, pipe);
trace_drm_vblank_event_queued(current->pid, pipe,
vblwait->request.sequence);
e->event.sequence = vblwait->request.sequence;
if ((seq - vblwait->request.sequence) <= (1 << 23)) {
e->event.sequence = seq;
e->event.tv_sec = now.tv_sec;
e->event.tv_usec = now.tv_usec;
drm_vblank_put(dev, pipe);
list_add_tail(&e->base.link, &e->base.file_priv->event_list);
wake_up_interruptible(&e->base.file_priv->event_wait);
vblwait->reply.sequence = seq;
trace_drm_vblank_event_delivered(current->pid, pipe,
vblwait->request.sequence);
} else {
list_add_tail(&e->base.link, &dev->vblank_event_list);
vblwait->reply.sequence = vblwait->request.sequence;
}
spin_unlock_irqrestore(&dev->event_lock, flags);
return 0;
err_unlock:
spin_unlock_irqrestore(&dev->event_lock, flags);
kfree(e);
err_put:
drm_vblank_put(dev, pipe);
return ret;
}
/**
* Wait for VBLANK.
*
* \param inode device inode.
* \param file_priv DRM file private.
* \param cmd command.
* \param data user argument, pointing to a drm_wait_vblank structure.
* \return zero on success or a negative number on failure.
*
* This function enables the vblank interrupt on the pipe requested, then
* sleeps waiting for the requested sequence number to occur, and drops
* the vblank interrupt refcount afterwards. (vblank irq disable follows that
* after a timeout with no further vblank waits scheduled).
*/
int drm_wait_vblank(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
union drm_wait_vblank *vblwait = data;
int ret = 0;
unsigned int flags, seq, crtc, high_crtc;
if ((!drm_dev_to_irq(dev)) || (!dev->irq_enabled))
return -EINVAL;
if (vblwait->request.type & _DRM_VBLANK_SIGNAL)
return -EINVAL;
if (vblwait->request.type &
~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
_DRM_VBLANK_HIGH_CRTC_MASK)) {
DRM_ERROR("Unsupported type value 0x%x, supported mask 0x%x\n",
vblwait->request.type,
(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK |
_DRM_VBLANK_HIGH_CRTC_MASK));
return -EINVAL;
}
flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK;
high_crtc = (vblwait->request.type & _DRM_VBLANK_HIGH_CRTC_MASK);
if (high_crtc)
crtc = high_crtc >> _DRM_VBLANK_HIGH_CRTC_SHIFT;
else
crtc = flags & _DRM_VBLANK_SECONDARY ? 1 : 0;
if (crtc >= dev->num_crtcs)
return -EINVAL;
ret = drm_vblank_get(dev, crtc);
if (ret) {
DRM_DEBUG("failed to acquire vblank counter, %d\n", ret);
return ret;
}
seq = drm_vblank_count(dev, crtc);
switch (vblwait->request.type & _DRM_VBLANK_TYPES_MASK) {
case _DRM_VBLANK_RELATIVE:
vblwait->request.sequence += seq;
vblwait->request.type &= ~_DRM_VBLANK_RELATIVE;
case _DRM_VBLANK_ABSOLUTE:
break;
default:
ret = -EINVAL;
goto done;
}
if (flags & _DRM_VBLANK_EVENT)
return drm_queue_vblank_event(dev, crtc, vblwait, file_priv);
if ((flags & _DRM_VBLANK_NEXTONMISS) &&
(seq - vblwait->request.sequence) <= (1<<23)) {
vblwait->request.sequence = seq + 1;
}
DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
vblwait->request.sequence, crtc);
dev->last_vblank_wait[crtc] = vblwait->request.sequence;
DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
(((drm_vblank_count(dev, crtc) -
vblwait->request.sequence) <= (1 << 23)) ||
!dev->irq_enabled));
if (ret != -EINTR) {
struct timeval now;
vblwait->reply.sequence = drm_vblank_count_and_time(dev, crtc, &now);
vblwait->reply.tval_sec = now.tv_sec;
vblwait->reply.tval_usec = now.tv_usec;
DRM_DEBUG("returning %d to client\n",
vblwait->reply.sequence);
} else {
DRM_DEBUG("vblank wait interrupted by signal\n");
}
done:
drm_vblank_put(dev, crtc);
return ret;
}
void drm_handle_vblank_events(struct drm_device *dev, int crtc)
{
struct drm_pending_vblank_event *e, *t;
struct timeval now;
unsigned long flags;
unsigned int seq;
seq = drm_vblank_count_and_time(dev, crtc, &now);
spin_lock_irqsave(&dev->event_lock, flags);
list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
if (e->pipe != crtc)
continue;
if ((seq - e->event.sequence) > (1<<23))
continue;
DRM_DEBUG("vblank event on %d, current %d\n",
e->event.sequence, seq);
e->event.sequence = seq;
e->event.tv_sec = now.tv_sec;
e->event.tv_usec = now.tv_usec;
drm_vblank_put(dev, e->pipe);
list_move_tail(&e->base.link, &e->base.file_priv->event_list);
wake_up_interruptible(&e->base.file_priv->event_wait);
trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
e->event.sequence);
}
spin_unlock_irqrestore(&dev->event_lock, flags);
trace_drm_vblank_event(crtc, seq);
}
/**
* drm_handle_vblank - handle a vblank event
* @dev: DRM device
* @crtc: where this event occurred
*
* Drivers should call this routine in their vblank interrupt handlers to
* update the vblank counter and send any signals that may be pending.
*/
bool drm_handle_vblank(struct drm_device *dev, int crtc)
{
u32 vblcount;
s64 diff_ns;
struct timeval tvblank;
unsigned long irqflags;
if (!dev->num_crtcs)
return false;
/* Need timestamp lock to prevent concurrent execution with
* vblank enable/disable, as this would cause inconsistent
* or corrupted timestamps and vblank counts.
*/
spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
/* Vblank irq handling disabled. Nothing to do. */
if (!dev->vblank_enabled[crtc]) {
spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
return false;
}
/* Fetch corresponding timestamp for this vblank interval from
* driver and store it in proper slot of timestamp ringbuffer.
*/
/* Get current timestamp and count. */
vblcount = atomic_read(&dev->_vblank_count[crtc]);
drm_get_last_vbltimestamp(dev, crtc, &tvblank, DRM_CALLED_FROM_VBLIRQ);
/* Compute time difference to timestamp of last vblank */
diff_ns = timeval_to_ns(&tvblank) -
timeval_to_ns(&vblanktimestamp(dev, crtc, vblcount));
/* Update vblank timestamp and count if at least
* DRM_REDUNDANT_VBLIRQ_THRESH_NS nanoseconds
* difference between last stored timestamp and current
* timestamp. A smaller difference means basically
* identical timestamps. Happens if this vblank has
* been already processed and this is a redundant call,
* e.g., due to spurious vblank interrupts. We need to
* ignore those for accounting.
*/
if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
/* Store new timestamp in ringbuffer. */
vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
/* Increment cooked vblank count. This also atomically commits
* the timestamp computed above.
*/
smp_mb__before_atomic_inc();
atomic_inc(&dev->_vblank_count[crtc]);
smp_mb__after_atomic_inc();
} else {
DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n",
crtc, (int) diff_ns);
}
DRM_WAKEUP(&dev->vbl_queue[crtc]);
drm_handle_vblank_events(dev, crtc);
spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
return true;
}
EXPORT_SYMBOL(drm_handle_vblank);