drm/i915: move pipe update code into crtc. (v2)

Daniel suggested this should move here.

v2: move vrr code.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/738c7aaeb63c7d2357ddd932f18787ec8a3cefeb.1612536383.git.jani.nikula@intel.com

1 files changed, 241 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/display/intel_crtc.c b/drivers/gpu/drm/i915/display/intel_crtc.c
index eb478712c381..8bfa8fc2efdb 100644
--- a/drivers/gpu/drm/i915/display/intel_crtc.c
+++ b/drivers/gpu/drm/i915/display/intel_crtc.c
@@ -10,6 +10,9 @@
 #include <drm/drm_plane.h>
 #include <drm/drm_plane_helper.h>
 
+#include "i915_trace.h"
+#include "i915_vgpu.h"
+
 #include "intel_atomic.h"
 #include "intel_atomic_plane.h"
 #include "intel_color.h"
@@ -17,8 +20,11 @@
 #include "intel_cursor.h"
 #include "intel_display_debugfs.h"
 #include "intel_display_types.h"
+#include "intel_dsi.h"
 #include "intel_pipe_crc.h"
+#include "intel_psr.h"
 #include "intel_sprite.h"
+#include "intel_vrr.h"
 #include "i9xx_plane.h"
 #include "skl_universal_plane.h"
 
@@ -332,3 +338,238 @@ fail:
 
 	return ret;
 }
+
+int intel_usecs_to_scanlines(const struct drm_display_mode *adjusted_mode,
+			     int usecs)
+{
+	/* paranoia */
+	if (!adjusted_mode->crtc_htotal)
+		return 1;
+
+	return DIV_ROUND_UP(usecs * adjusted_mode->crtc_clock,
+			    1000 * adjusted_mode->crtc_htotal);
+}
+
+static int intel_mode_vblank_start(const struct drm_display_mode *mode)
+{
+	int vblank_start = mode->crtc_vblank_start;
+
+	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
+		vblank_start = DIV_ROUND_UP(vblank_start, 2);
+
+	return vblank_start;
+}
+
+/**
+ * intel_pipe_update_start() - start update of a set of display registers
+ * @new_crtc_state: the new crtc state
+ *
+ * Mark the start of an update to pipe registers that should be updated
+ * atomically regarding vblank. If the next vblank will happens within
+ * the next 100 us, this function waits until the vblank passes.
+ *
+ * After a successful call to this function, interrupts will be disabled
+ * until a subsequent call to intel_pipe_update_end(). That is done to
+ * avoid random delays.
+ */
+void intel_pipe_update_start(const struct intel_crtc_state *new_crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(new_crtc_state->uapi.crtc);
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+	const struct drm_display_mode *adjusted_mode = &new_crtc_state->hw.adjusted_mode;
+	long timeout = msecs_to_jiffies_timeout(1);
+	int scanline, min, max, vblank_start;
+	wait_queue_head_t *wq = drm_crtc_vblank_waitqueue(&crtc->base);
+	bool need_vlv_dsi_wa = (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) &&
+		intel_crtc_has_type(new_crtc_state, INTEL_OUTPUT_DSI);
+	DEFINE_WAIT(wait);
+
+	if (new_crtc_state->uapi.async_flip)
+		return;
+
+	if (new_crtc_state->vrr.enable)
+		vblank_start = intel_vrr_vmax_vblank_start(new_crtc_state);
+	else
+		vblank_start = intel_mode_vblank_start(adjusted_mode);
+
+	/* FIXME needs to be calibrated sensibly */
+	min = vblank_start - intel_usecs_to_scanlines(adjusted_mode,
+						      VBLANK_EVASION_TIME_US);
+	max = vblank_start - 1;
+
+	if (min <= 0 || max <= 0)
+		goto irq_disable;
+
+	if (drm_WARN_ON(&dev_priv->drm, drm_crtc_vblank_get(&crtc->base)))
+		goto irq_disable;
+
+	/*
+	 * Wait for psr to idle out after enabling the VBL interrupts
+	 * VBL interrupts will start the PSR exit and prevent a PSR
+	 * re-entry as well.
+	 */
+	intel_psr_wait_for_idle(new_crtc_state);
+
+	local_irq_disable();
+
+	crtc->debug.min_vbl = min;
+	crtc->debug.max_vbl = max;
+	trace_intel_pipe_update_start(crtc);
+
+	for (;;) {
+		/*
+		 * prepare_to_wait() has a memory barrier, which guarantees
+		 * other CPUs can see the task state update by the time we
+		 * read the scanline.
+		 */
+		prepare_to_wait(wq, &wait, TASK_UNINTERRUPTIBLE);
+
+		scanline = intel_get_crtc_scanline(crtc);
+		if (scanline < min || scanline > max)
+			break;
+
+		if (!timeout) {
+			drm_err(&dev_priv->drm,
+				"Potential atomic update failure on pipe %c\n",
+				pipe_name(crtc->pipe));
+			break;
+		}
+
+		local_irq_enable();
+
+		timeout = schedule_timeout(timeout);
+
+		local_irq_disable();
+	}
+
+	finish_wait(wq, &wait);
+
+	drm_crtc_vblank_put(&crtc->base);
+
+	/*
+	 * On VLV/CHV DSI the scanline counter would appear to
+	 * increment approx. 1/3 of a scanline before start of vblank.
+	 * The registers still get latched at start of vblank however.
+	 * This means we must not write any registers on the first
+	 * line of vblank (since not the whole line is actually in
+	 * vblank). And unfortunately we can't use the interrupt to
+	 * wait here since it will fire too soon. We could use the
+	 * frame start interrupt instead since it will fire after the
+	 * critical scanline, but that would require more changes
+	 * in the interrupt code. So for now we'll just do the nasty
+	 * thing and poll for the bad scanline to pass us by.
+	 *
+	 * FIXME figure out if BXT+ DSI suffers from this as well
+	 */
+	while (need_vlv_dsi_wa && scanline == vblank_start)
+		scanline = intel_get_crtc_scanline(crtc);
+
+	crtc->debug.scanline_start = scanline;
+	crtc->debug.start_vbl_time = ktime_get();
+	crtc->debug.start_vbl_count = intel_crtc_get_vblank_counter(crtc);
+
+	trace_intel_pipe_update_vblank_evaded(crtc);
+	return;
+
+irq_disable:
+	local_irq_disable();
+}
+
+#if IS_ENABLED(CONFIG_DRM_I915_DEBUG_VBLANK_EVADE)
+static void dbg_vblank_evade(struct intel_crtc *crtc, ktime_t end)
+{
+	u64 delta = ktime_to_ns(ktime_sub(end, crtc->debug.start_vbl_time));
+	unsigned int h;
+
+	h = ilog2(delta >> 9);
+	if (h >= ARRAY_SIZE(crtc->debug.vbl.times))
+		h = ARRAY_SIZE(crtc->debug.vbl.times) - 1;
+	crtc->debug.vbl.times[h]++;
+
+	crtc->debug.vbl.sum += delta;
+	if (!crtc->debug.vbl.min || delta < crtc->debug.vbl.min)
+		crtc->debug.vbl.min = delta;
+	if (delta > crtc->debug.vbl.max)
+		crtc->debug.vbl.max = delta;
+
+	if (delta > 1000 * VBLANK_EVASION_TIME_US) {
+		drm_dbg_kms(crtc->base.dev,
+			    "Atomic update on pipe (%c) took %lld us, max time under evasion is %u us\n",
+			    pipe_name(crtc->pipe),
+			    div_u64(delta, 1000),
+			    VBLANK_EVASION_TIME_US);
+		crtc->debug.vbl.over++;
+	}
+}
+#else
+static void dbg_vblank_evade(struct intel_crtc *crtc, ktime_t end) {}
+#endif
+
+/**
+ * intel_pipe_update_end() - end update of a set of display registers
+ * @new_crtc_state: the new crtc state
+ *
+ * Mark the end of an update started with intel_pipe_update_start(). This
+ * re-enables interrupts and verifies the update was actually completed
+ * before a vblank.
+ */
+void intel_pipe_update_end(struct intel_crtc_state *new_crtc_state)
+{
+	struct intel_crtc *crtc = to_intel_crtc(new_crtc_state->uapi.crtc);
+	enum pipe pipe = crtc->pipe;
+	int scanline_end = intel_get_crtc_scanline(crtc);
+	u32 end_vbl_count = intel_crtc_get_vblank_counter(crtc);
+	ktime_t end_vbl_time = ktime_get();
+	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
+
+	if (new_crtc_state->uapi.async_flip)
+		return;
+
+	trace_intel_pipe_update_end(crtc, end_vbl_count, scanline_end);
+
+	/*
+	 * Incase of mipi dsi command mode, we need to set frame update
+	 * request for every commit.
+	 */
+	if (INTEL_GEN(dev_priv) >= 11 &&
+	    intel_crtc_has_type(new_crtc_state, INTEL_OUTPUT_DSI))
+		icl_dsi_frame_update(new_crtc_state);
+
+	/* We're still in the vblank-evade critical section, this can't race.
+	 * Would be slightly nice to just grab the vblank count and arm the
+	 * event outside of the critical section - the spinlock might spin for a
+	 * while ... */
+	if (new_crtc_state->uapi.event) {
+		drm_WARN_ON(&dev_priv->drm,
+			    drm_crtc_vblank_get(&crtc->base) != 0);
+
+		spin_lock(&crtc->base.dev->event_lock);
+		drm_crtc_arm_vblank_event(&crtc->base,
+					  new_crtc_state->uapi.event);
+		spin_unlock(&crtc->base.dev->event_lock);
+
+		new_crtc_state->uapi.event = NULL;
+	}
+
+	local_irq_enable();
+
+	/* Send VRR Push to terminate Vblank */
+	intel_vrr_send_push(new_crtc_state);
+
+	if (intel_vgpu_active(dev_priv))
+		return;
+
+	if (crtc->debug.start_vbl_count &&
+	    crtc->debug.start_vbl_count != end_vbl_count) {
+		drm_err(&dev_priv->drm,
+			"Atomic update failure on pipe %c (start=%u end=%u) time %lld us, min %d, max %d, scanline start %d, end %d\n",
+			pipe_name(pipe), crtc->debug.start_vbl_count,
+			end_vbl_count,
+			ktime_us_delta(end_vbl_time,
+				       crtc->debug.start_vbl_time),
+			crtc->debug.min_vbl, crtc->debug.max_vbl,
+			crtc->debug.scanline_start, scanline_end);
+	}
+
+	dbg_vblank_evade(crtc, end_vbl_time);
+}