cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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drm_vblank.h (9255B)


      1/*
      2 * Copyright 2016 Intel Corp.
      3 *
      4 * Permission is hereby granted, free of charge, to any person obtaining a
      5 * copy of this software and associated documentation files (the "Software"),
      6 * to deal in the Software without restriction, including without limitation
      7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
      8 * and/or sell copies of the Software, and to permit persons to whom the
      9 * Software is furnished to do so, subject to the following conditions:
     10 *
     11 * The above copyright notice and this permission notice (including the next
     12 * paragraph) shall be included in all copies or substantial portions of the
     13 * Software.
     14 *
     15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     18 * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
     19 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
     20 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
     21 * OTHER DEALINGS IN THE SOFTWARE.
     22 */
     23
     24#ifndef _DRM_VBLANK_H_
     25#define _DRM_VBLANK_H_
     26
     27#include <linux/seqlock.h>
     28#include <linux/idr.h>
     29#include <linux/poll.h>
     30#include <linux/kthread.h>
     31
     32#include <drm/drm_file.h>
     33#include <drm/drm_modes.h>
     34
     35struct drm_device;
     36struct drm_crtc;
     37struct drm_vblank_work;
     38
     39/**
     40 * struct drm_pending_vblank_event - pending vblank event tracking
     41 */
     42struct drm_pending_vblank_event {
     43	/**
     44	 * @base: Base structure for tracking pending DRM events.
     45	 */
     46	struct drm_pending_event base;
     47	/**
     48	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
     49	 */
     50	unsigned int pipe;
     51	/**
     52	 * @sequence: frame event should be triggered at
     53	 */
     54	u64 sequence;
     55	/**
     56	 * @event: Actual event which will be sent to userspace.
     57	 */
     58	union {
     59		/**
     60		 * @event.base: DRM event base class.
     61		 */
     62		struct drm_event base;
     63
     64		/**
     65		 * @event.vbl:
     66		 *
     67		 * Event payload for vblank events, requested through
     68		 * either the MODE_PAGE_FLIP or MODE_ATOMIC IOCTL. Also
     69		 * generated by the legacy WAIT_VBLANK IOCTL, but new userspace
     70		 * should use MODE_QUEUE_SEQUENCE and &event.seq instead.
     71		 */
     72		struct drm_event_vblank vbl;
     73
     74		/**
     75		 * @event.seq: Event payload for the MODE_QUEUEU_SEQUENCE IOCTL.
     76		 */
     77		struct drm_event_crtc_sequence seq;
     78	} event;
     79};
     80
     81/**
     82 * struct drm_vblank_crtc - vblank tracking for a CRTC
     83 *
     84 * This structure tracks the vblank state for one CRTC.
     85 *
     86 * Note that for historical reasons - the vblank handling code is still shared
     87 * with legacy/non-kms drivers - this is a free-standing structure not directly
     88 * connected to &struct drm_crtc. But all public interface functions are taking
     89 * a &struct drm_crtc to hide this implementation detail.
     90 */
     91struct drm_vblank_crtc {
     92	/**
     93	 * @dev: Pointer to the &drm_device.
     94	 */
     95	struct drm_device *dev;
     96	/**
     97	 * @queue: Wait queue for vblank waiters.
     98	 */
     99	wait_queue_head_t queue;
    100	/**
    101	 * @disable_timer: Disable timer for the delayed vblank disabling
    102	 * hysteresis logic. Vblank disabling is controlled through the
    103	 * drm_vblank_offdelay module option and the setting of the
    104	 * &drm_device.max_vblank_count value.
    105	 */
    106	struct timer_list disable_timer;
    107
    108	/**
    109	 * @seqlock: Protect vblank count and time.
    110	 */
    111	seqlock_t seqlock;
    112
    113	/**
    114	 * @count:
    115	 *
    116	 * Current software vblank counter.
    117	 *
    118	 * Note that for a given vblank counter value drm_crtc_handle_vblank()
    119	 * and drm_crtc_vblank_count() or drm_crtc_vblank_count_and_time()
    120	 * provide a barrier: Any writes done before calling
    121	 * drm_crtc_handle_vblank() will be visible to callers of the later
    122	 * functions, iff the vblank count is the same or a later one.
    123	 *
    124	 * IMPORTANT: This guarantee requires barriers, therefor never access
    125	 * this field directly. Use drm_crtc_vblank_count() instead.
    126	 */
    127	atomic64_t count;
    128	/**
    129	 * @time: Vblank timestamp corresponding to @count.
    130	 */
    131	ktime_t time;
    132
    133	/**
    134	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
    135	 * this refcount reaches 0 can the hardware interrupt be disabled using
    136	 * @disable_timer.
    137	 */
    138	atomic_t refcount;
    139	/**
    140	 * @last: Protected by &drm_device.vbl_lock, used for wraparound handling.
    141	 */
    142	u32 last;
    143	/**
    144	 * @max_vblank_count:
    145	 *
    146	 * Maximum value of the vblank registers for this crtc. This value +1
    147	 * will result in a wrap-around of the vblank register. It is used
    148	 * by the vblank core to handle wrap-arounds.
    149	 *
    150	 * If set to zero the vblank core will try to guess the elapsed vblanks
    151	 * between times when the vblank interrupt is disabled through
    152	 * high-precision timestamps. That approach is suffering from small
    153	 * races and imprecision over longer time periods, hence exposing a
    154	 * hardware vblank counter is always recommended.
    155	 *
    156	 * This is the runtime configurable per-crtc maximum set through
    157	 * drm_crtc_set_max_vblank_count(). If this is used the driver
    158	 * must leave the device wide &drm_device.max_vblank_count at zero.
    159	 *
    160	 * If non-zero, &drm_crtc_funcs.get_vblank_counter must be set.
    161	 */
    162	u32 max_vblank_count;
    163	/**
    164	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
    165	 * For legacy driver bit 2 additionally tracks whether an additional
    166	 * temporary vblank reference has been acquired to paper over the
    167	 * hardware counter resetting/jumping. KMS drivers should instead just
    168	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
    169	 * save and restore the vblank count.
    170	 */
    171	unsigned int inmodeset;
    172	/**
    173	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
    174	 * structure.
    175	 */
    176	unsigned int pipe;
    177	/**
    178	 * @framedur_ns: Frame/Field duration in ns, used by
    179	 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
    180	 * drm_calc_timestamping_constants().
    181	 */
    182	int framedur_ns;
    183	/**
    184	 * @linedur_ns: Line duration in ns, used by
    185	 * drm_crtc_vblank_helper_get_vblank_timestamp() and computed by
    186	 * drm_calc_timestamping_constants().
    187	 */
    188	int linedur_ns;
    189
    190	/**
    191	 * @hwmode:
    192	 *
    193	 * Cache of the current hardware display mode. Only valid when @enabled
    194	 * is set. This is used by helpers like
    195	 * drm_crtc_vblank_helper_get_vblank_timestamp(). We can't just access
    196	 * the hardware mode by e.g. looking at &drm_crtc_state.adjusted_mode,
    197	 * because that one is really hard to get from interrupt context.
    198	 */
    199	struct drm_display_mode hwmode;
    200
    201	/**
    202	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
    203	 * avoid double-disabling and hence corrupting saved state. Needed by
    204	 * drivers not using atomic KMS, since those might go through their CRTC
    205	 * disabling functions multiple times.
    206	 */
    207	bool enabled;
    208
    209	/**
    210	 * @worker: The &kthread_worker used for executing vblank works.
    211	 */
    212	struct kthread_worker *worker;
    213
    214	/**
    215	 * @pending_work: A list of scheduled &drm_vblank_work items that are
    216	 * waiting for a future vblank.
    217	 */
    218	struct list_head pending_work;
    219
    220	/**
    221	 * @work_wait_queue: The wait queue used for signaling that a
    222	 * &drm_vblank_work item has either finished executing, or was
    223	 * cancelled.
    224	 */
    225	wait_queue_head_t work_wait_queue;
    226};
    227
    228int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
    229bool drm_dev_has_vblank(const struct drm_device *dev);
    230u64 drm_crtc_vblank_count(struct drm_crtc *crtc);
    231u64 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
    232				   ktime_t *vblanktime);
    233void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
    234			       struct drm_pending_vblank_event *e);
    235void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
    236			      struct drm_pending_vblank_event *e);
    237void drm_vblank_set_event(struct drm_pending_vblank_event *e,
    238			  u64 *seq,
    239			  ktime_t *now);
    240bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
    241bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
    242int drm_crtc_vblank_get(struct drm_crtc *crtc);
    243void drm_crtc_vblank_put(struct drm_crtc *crtc);
    244void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
    245void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
    246void drm_crtc_vblank_off(struct drm_crtc *crtc);
    247void drm_crtc_vblank_reset(struct drm_crtc *crtc);
    248void drm_crtc_vblank_on(struct drm_crtc *crtc);
    249u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc);
    250void drm_crtc_vblank_restore(struct drm_crtc *crtc);
    251
    252void drm_calc_timestamping_constants(struct drm_crtc *crtc,
    253				     const struct drm_display_mode *mode);
    254wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc);
    255void drm_crtc_set_max_vblank_count(struct drm_crtc *crtc,
    256				   u32 max_vblank_count);
    257
    258/*
    259 * Helpers for struct drm_crtc_funcs
    260 */
    261
    262typedef bool (*drm_vblank_get_scanout_position_func)(struct drm_crtc *crtc,
    263						     bool in_vblank_irq,
    264						     int *vpos, int *hpos,
    265						     ktime_t *stime,
    266						     ktime_t *etime,
    267						     const struct drm_display_mode *mode);
    268
    269bool
    270drm_crtc_vblank_helper_get_vblank_timestamp_internal(struct drm_crtc *crtc,
    271						     int *max_error,
    272						     ktime_t *vblank_time,
    273						     bool in_vblank_irq,
    274						     drm_vblank_get_scanout_position_func get_scanout_position);
    275bool drm_crtc_vblank_helper_get_vblank_timestamp(struct drm_crtc *crtc,
    276						 int *max_error,
    277						 ktime_t *vblank_time,
    278						 bool in_vblank_irq);
    279
    280#endif