drm: Extract&Document drm_irq.h

The drm_irq docs want one function from drmP.h, but that one is a
serious mess. Extract it, and while at it improve the docs a bit.
There's a bit a header loop issue since core data structures like
drm_device and drm_driver aren't in their own headers yet, which means
the drm_irq.h include in drmP.h needs to be in just the right spot :(

Also noticed that drm_vblank_crtc->last_wait is entirely unused,
remove it.

v2: git add drm_irq.h ...

Acked-by: Chris Wilson <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>

Documentation/gpu/drm-kms.rst

···
 .. kernel-doc:: drivers/gpu/drm/drm_irq.c
    :export:
 
-.. kernel-doc:: include/drm/drmP.h
-   :functions: drm_crtc_vblank_waitqueue
+.. kernel-doc:: include/drm/drm_irq.h
+   :internal:

drivers/gpu/drm/drm_irq.c

···
 
 	DRM_DEBUG("waiting on vblank count %d, crtc %u\n",
 		  vblwait->request.sequence, pipe);
-	vblank->last_wait = vblwait->request.sequence;
 	DRM_WAIT_ON(ret, vblank->queue, 3 * HZ,
 		    (((drm_vblank_count(dev, pipe) -
 		       vblwait->request.sequence) <= (1 << 23)) ||

include/drm/drmP.h

···
 #include <linux/poll.h>
 #include <linux/ratelimit.h>
 #include <linux/sched.h>
-#include <linux/seqlock.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/vmalloc.h>
···
 struct drm_dma_handle;
 struct drm_gem_object;
 struct drm_master;
+struct drm_vblank_crtc;
 
 struct device_node;
 struct videomode;
···
 	struct mutex debugfs_lock; /* Protects debugfs_list. */
 };
 
-
-struct drm_pending_vblank_event {
-	struct drm_pending_event base;
-	unsigned int pipe;
-	struct drm_event_vblank event;
-};
-
-struct drm_vblank_crtc {
-	struct drm_device *dev;		/* pointer to the drm_device */
-	wait_queue_head_t queue;	/**< VBLANK wait queue */
-	struct timer_list disable_timer;		/* delayed disable timer */
-
-	seqlock_t seqlock;		/* protects vblank count and time */
-
-	u32 count;			/* vblank counter */
-	struct timeval time;		/* vblank timestamp */
-
-	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
-	u32 last;			/* protected by dev->vbl_lock, used */
-					/* for wraparound handling */
-	u32 last_wait;			/* Last vblank seqno waited per CRTC */
-	unsigned int inmodeset;		/* Display driver is setting mode */
-	unsigned int pipe;		/* crtc index */
-	int framedur_ns;		/* frame/field duration in ns */
-	int linedur_ns;			/* line duration in ns */
-	bool enabled;			/* so we don't call enable more than
-					   once per disable */
-};
-
 /**
  * DRM device structure. This structure represent a complete card that
  * may contain multiple heads.
···
 	int switch_power_state;
 };
 
+#include <drm/drm_irq.h>
+
 #define DRM_SWITCH_POWER_ON 0
 #define DRM_SWITCH_POWER_OFF 1
 #define DRM_SWITCH_POWER_CHANGING 2
···
  * These are exported to drivers so that they can implement fencing using
  * DMA quiscent + idle. DMA quiescent usually requires the hardware lock.
  */
-
-				/* IRQ support (drm_irq.h) */
-extern int drm_irq_install(struct drm_device *dev, int irq);
-extern int drm_irq_uninstall(struct drm_device *dev);
-
-extern int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
-extern int drm_wait_vblank(struct drm_device *dev, void *data,
-			   struct drm_file *filp);
-extern u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe);
-extern u32 drm_crtc_vblank_count(struct drm_crtc *crtc);
-extern u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
-					  struct timeval *vblanktime);
-extern void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
-				       struct drm_pending_vblank_event *e);
-extern void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
-				      struct drm_pending_vblank_event *e);
-extern bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
-extern bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
-extern int drm_crtc_vblank_get(struct drm_crtc *crtc);
-extern void drm_crtc_vblank_put(struct drm_crtc *crtc);
-extern void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
-extern void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
-extern void drm_vblank_off(struct drm_device *dev, unsigned int pipe);
-extern void drm_vblank_on(struct drm_device *dev, unsigned int pipe);
-extern void drm_crtc_vblank_off(struct drm_crtc *crtc);
-extern void drm_crtc_vblank_reset(struct drm_crtc *crtc);
-extern void drm_crtc_vblank_on(struct drm_crtc *crtc);
-extern void drm_vblank_cleanup(struct drm_device *dev);
-extern u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
-extern u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe);
-
-extern int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
-						 unsigned int pipe, int *max_error,
-						 struct timeval *vblank_time,
-						 unsigned flags,
-						 const struct drm_display_mode *mode);
-extern void drm_calc_timestamping_constants(struct drm_crtc *crtc,
-					    const struct drm_display_mode *mode);
-
-/**
- * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
- * @crtc: which CRTC's vblank waitqueue to retrieve
- *
- * This function returns a pointer to the vblank waitqueue for the CRTC.
- * Drivers can use this to implement vblank waits using wait_event() & co.
- */
-static inline wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
-{
-	return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
-}
 
 /* Modesetting support */
 extern void drm_vblank_pre_modeset(struct drm_device *dev, unsigned int pipe);

include/drm/drm_irq.h

···
+/*
+ * Copyright 2016 Intel Corp.
+ *
+ * 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.
+ */
+
+#ifndef _DRM_IRQ_H_
+#define _DRM_IRQ_H_
+
+#include <linux/seqlock.h>
+
+/**
+ * struct drm_pending_vblank_event - pending vblank event tracking
+ */
+struct drm_pending_vblank_event {
+	/**
+	 * @base: Base structure for tracking pending DRM events.
+	 */
+	struct drm_pending_event base;
+	/**
+	 * @pipe: drm_crtc_index() of the &drm_crtc this event is for.
+	 */
+	unsigned int pipe;
+	/**
+	 * @event: Actual event which will be sent to userspace.
+	 */
+	struct drm_event_vblank event;
+};
+
+/**
+ * struct drm_vblank_crtc - vblank tracking for a CRTC
+ *
+ * This structure tracks the vblank state for one CRTC.
+ *
+ * Note that for historical reasons - the vblank handling code is still shared
+ * with legacy/non-kms drivers - this is a free-standing structure not directly
+ * connected to struct &drm_crtc. But all public interface functions are taking
+ * a struct &drm_crtc to hide this implementation detail.
+ */
+struct drm_vblank_crtc {
+	/**
+	 * @dev: Pointer to the &drm_device.
+	 */
+	struct drm_device *dev;
+	/**
+	 * @queue: Wait queue for vblank waiters.
+	 */
+	wait_queue_head_t queue;	/**< VBLANK wait queue */
+	/**
+	 * @disable_timer: Disable timer for the delayed vblank disabling
+	 * hysteresis logic. Vblank disabling is controlled through the
+	 * drm_vblank_offdelay module option and the setting of the
+	 * max_vblank_count value in the &drm_device structure.
+	 */
+	struct timer_list disable_timer;
+
+	/**
+	 * @seqlock: Protect vblank count and time.
+	 */
+	seqlock_t seqlock;		/* protects vblank count and time */
+
+	/**
+	 * @count: Current software vblank counter.
+	 */
+	u32 count;
+	/**
+	 * @time: Vblank timestamp corresponding to @count.
+	 */
+	struct timeval time;
+
+	/**
+	 * @refcount: Number of users/waiters of the vblank interrupt. Only when
+	 * this refcount reaches 0 can the hardware interrupt be disabled using
+	 * @disable_timer.
+	 */
+	atomic_t refcount;		/* number of users of vblank interruptsper crtc */
+	/**
+	 * @last: Protected by dev->vbl_lock, used for wraparound handling.
+	 */
+	u32 last;
+	/**
+	 * @inmodeset: Tracks whether the vblank is disabled due to a modeset.
+	 * For legacy driver bit 2 additionally tracks whether an additional
+	 * temporary vblank reference has been acquired to paper over the
+	 * hardware counter resetting/jumping. KMS drivers should instead just
+	 * call drm_crtc_vblank_off() and drm_crtc_vblank_on(), which explicitly
+	 * save and restore the vblank count.
+	 */
+	unsigned int inmodeset;		/* Display driver is setting mode */
+	/**
+	 * @pipe: drm_crtc_index() of the &drm_crtc corresponding to this
+	 * structure.
+	 */
+	unsigned int pipe;
+	/**
+	 * @framedur_ns: Frame/Field duration in ns, used by
+	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
+	 * drm_calc_timestamping_constants().
+	 */
+	int framedur_ns;
+	/**
+	 * @linedur_ns: Line duration in ns, used by
+	 * drm_calc_vbltimestamp_from_scanoutpos() and computed by
+	 * drm_calc_timestamping_constants().
+	 */
+	int linedur_ns;
+	/**
+	 * @enabled: Tracks the enabling state of the corresponding &drm_crtc to
+	 * avoid double-disabling and hence corrupting saved state. Needed by
+	 * drivers not using atomic KMS, since those might go through their CRTC
+	 * disabling functions multiple times.
+	 */
+	bool enabled;
+};
+
+extern int drm_irq_install(struct drm_device *dev, int irq);
+extern int drm_irq_uninstall(struct drm_device *dev);
+
+extern int drm_vblank_init(struct drm_device *dev, unsigned int num_crtcs);
+extern int drm_wait_vblank(struct drm_device *dev, void *data,
+			   struct drm_file *filp);
+extern u32 drm_vblank_count(struct drm_device *dev, unsigned int pipe);
+extern u32 drm_crtc_vblank_count(struct drm_crtc *crtc);
+extern u32 drm_crtc_vblank_count_and_time(struct drm_crtc *crtc,
+					  struct timeval *vblanktime);
+extern void drm_crtc_send_vblank_event(struct drm_crtc *crtc,
+				       struct drm_pending_vblank_event *e);
+extern void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
+				      struct drm_pending_vblank_event *e);
+extern bool drm_handle_vblank(struct drm_device *dev, unsigned int pipe);
+extern bool drm_crtc_handle_vblank(struct drm_crtc *crtc);
+extern int drm_crtc_vblank_get(struct drm_crtc *crtc);
+extern void drm_crtc_vblank_put(struct drm_crtc *crtc);
+extern void drm_wait_one_vblank(struct drm_device *dev, unsigned int pipe);
+extern void drm_crtc_wait_one_vblank(struct drm_crtc *crtc);
+extern void drm_vblank_off(struct drm_device *dev, unsigned int pipe);
+extern void drm_vblank_on(struct drm_device *dev, unsigned int pipe);
+extern void drm_crtc_vblank_off(struct drm_crtc *crtc);
+extern void drm_crtc_vblank_reset(struct drm_crtc *crtc);
+extern void drm_crtc_vblank_on(struct drm_crtc *crtc);
+extern void drm_vblank_cleanup(struct drm_device *dev);
+extern u32 drm_accurate_vblank_count(struct drm_crtc *crtc);
+extern u32 drm_vblank_no_hw_counter(struct drm_device *dev, unsigned int pipe);
+
+extern int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev,
+						 unsigned int pipe, int *max_error,
+						 struct timeval *vblank_time,
+						 unsigned flags,
+						 const struct drm_display_mode *mode);
+extern void drm_calc_timestamping_constants(struct drm_crtc *crtc,
+					    const struct drm_display_mode *mode);
+
+/**
+ * drm_crtc_vblank_waitqueue - get vblank waitqueue for the CRTC
+ * @crtc: which CRTC's vblank waitqueue to retrieve
+ *
+ * This function returns a pointer to the vblank waitqueue for the CRTC.
+ * Drivers can use this to implement vblank waits using wait_event() and related
+ * functions.
+ */
+static inline wait_queue_head_t *drm_crtc_vblank_waitqueue(struct drm_crtc *crtc)
+{
+	return &crtc->dev->vblank[drm_crtc_index(crtc)].queue;
+}
+
+#endif