Set the flag vblank_disable_immediate = true to turn off vblank irqs
immediately as soon as drm_vblank_put is requested so that there are
no irqs triggered during idle state. This will reduce cpu wakeups
and help in power saving.

To enable vblank_disable_immediate flag the underlying KMS driver
needs to support high precision vblank timestamping and also a
reliable way of providing vblank counter which is incrementing
at the leading edge of vblank.

This patch also brings in changes to support vblank_disable_immediate
requirement in dpu driver.

Changes in v1:
 - Specify reason to add vblank timestamp support. (Rob)
 - Add changes to provide vblank counter from dpu driver.

Changes in v2:
 - fix warn stack reported by Rob with v2 patch

Signed-off-by: Kalyan Thota <kaly...@codeaurora.org>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c    | 80 +++++++++++++++++++++++++++++
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 28 +++++++++-
 drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h | 11 ++++
 drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c     |  5 ++
 4 files changed, 123 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c 
b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index d4662e8..9a80981 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -65,6 +65,83 @@ static void dpu_crtc_destroy(struct drm_crtc *crtc)
        kfree(dpu_crtc);
 }
 
+static struct drm_encoder *get_encoder_from_crtc(struct drm_crtc *crtc)
+{
+       struct drm_device *dev = crtc->dev;
+       struct drm_encoder *encoder;
+
+       drm_for_each_encoder(encoder, dev)
+               if (encoder->crtc == crtc)
+                       return encoder;
+
+       return NULL;
+}
+
+static u32 dpu_crtc_get_vblank_counter(struct drm_crtc *crtc)
+{
+       struct drm_encoder *encoder;
+
+       encoder = get_encoder_from_crtc(crtc);
+       if (!encoder) {
+               DRM_ERROR("no encoder found for crtc %d\n", crtc->index);
+               return false;
+       }
+
+       return dpu_encoder_get_frame_count(encoder);
+}
+
+static bool dpu_crtc_get_scanout_position(struct drm_crtc *crtc,
+                                          bool in_vblank_irq,
+                                          int *vpos, int *hpos,
+                                          ktime_t *stime, ktime_t *etime,
+                                          const struct drm_display_mode *mode)
+{
+       unsigned int pipe = crtc->index;
+       struct drm_encoder *encoder;
+       int line, vsw, vbp, vactive_start, vactive_end, vfp_end;
+
+       encoder = get_encoder_from_crtc(crtc);
+       if (!encoder) {
+               DRM_ERROR("no encoder found for crtc %d\n", pipe);
+               return false;
+       }
+
+       vsw = mode->crtc_vsync_end - mode->crtc_vsync_start;
+       vbp = mode->crtc_vtotal - mode->crtc_vsync_end;
+
+       /*
+        * the line counter is 1 at the start of the VSYNC pulse and VTOTAL at
+        * the end of VFP. Translate the porch values relative to the line
+        * counter positions.
+        */
+
+       vactive_start = vsw + vbp + 1;
+       vactive_end = vactive_start + mode->crtc_vdisplay;
+
+       /* last scan line before VSYNC */
+       vfp_end = mode->crtc_vtotal;
+
+       if (stime)
+               *stime = ktime_get();
+
+       line = dpu_encoder_get_linecount(encoder);
+
+       if (line < vactive_start)
+               line -= vactive_start;
+       else if (line > vactive_end)
+               line = line - vfp_end - vactive_start;
+       else
+               line -= vactive_start;
+
+       *vpos = line;
+       *hpos = 0;
+
+       if (etime)
+               *etime = ktime_get();
+
+       return true;
+}
+
 static void _dpu_crtc_setup_blend_cfg(struct dpu_crtc_mixer *mixer,
                struct dpu_plane_state *pstate, struct dpu_format *format)
 {
@@ -1243,6 +1320,8 @@ static const struct drm_crtc_funcs dpu_crtc_funcs = {
        .early_unregister = dpu_crtc_early_unregister,
        .enable_vblank  = msm_crtc_enable_vblank,
        .disable_vblank = msm_crtc_disable_vblank,
+       .get_vblank_timestamp = drm_crtc_vblank_helper_get_vblank_timestamp,
+       .get_vblank_counter = dpu_crtc_get_vblank_counter,
 };
 
 static const struct drm_crtc_helper_funcs dpu_crtc_helper_funcs = {
@@ -1251,6 +1330,7 @@ static const struct drm_crtc_helper_funcs 
dpu_crtc_helper_funcs = {
        .atomic_check = dpu_crtc_atomic_check,
        .atomic_begin = dpu_crtc_atomic_begin,
        .atomic_flush = dpu_crtc_atomic_flush,
+       .get_scanout_position = dpu_crtc_get_scanout_position,
 };
 
 /* initialize crtc */
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c 
b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
index f7f5c25..fb6546c 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
@@ -425,6 +425,32 @@ int dpu_encoder_helper_unregister_irq(struct 
dpu_encoder_phys *phys_enc,
        return 0;
 }
 
+int dpu_encoder_get_frame_count(struct drm_encoder *drm_enc)
+{
+       struct dpu_encoder_virt *dpu_enc;
+       struct dpu_encoder_phys *phy_enc;
+
+       dpu_enc = to_dpu_encoder_virt(drm_enc);
+       phy_enc = dpu_enc ? dpu_enc->cur_master : NULL;
+
+       return phy_enc ? atomic_read(&phy_enc->vsync_cnt) : 0;
+}
+
+int dpu_encoder_get_linecount(struct drm_encoder *drm_enc)
+{
+       struct dpu_encoder_virt *dpu_enc;
+       struct dpu_encoder_phys *phys;
+       int linecount = 0;
+
+       dpu_enc = to_dpu_encoder_virt(drm_enc);
+       phys = dpu_enc ? dpu_enc->cur_master : NULL;
+
+       if (phys && phys->ops.get_line_count)
+               linecount = phys->ops.get_line_count(phys);
+
+       return linecount;
+}
+
 void dpu_encoder_get_hw_resources(struct drm_encoder *drm_enc,
                                  struct dpu_encoder_hw_resources *hw_res)
 {
@@ -1296,12 +1322,12 @@ static void dpu_encoder_vblank_callback(struct 
drm_encoder *drm_enc,
        DPU_ATRACE_BEGIN("encoder_vblank_callback");
        dpu_enc = to_dpu_encoder_virt(drm_enc);
 
+       atomic_inc(&phy_enc->vsync_cnt);
        spin_lock_irqsave(&dpu_enc->enc_spinlock, lock_flags);
        if (dpu_enc->crtc)
                dpu_crtc_vblank_callback(dpu_enc->crtc);
        spin_unlock_irqrestore(&dpu_enc->enc_spinlock, lock_flags);
 
-       atomic_inc(&phy_enc->vsync_cnt);
        DPU_ATRACE_END("encoder_vblank_callback");
 }
 
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h 
b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
index b491346..99a5d73 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
@@ -156,5 +156,16 @@ void dpu_encoder_prepare_commit(struct drm_encoder 
*drm_enc);
  */
 void dpu_encoder_set_idle_timeout(struct drm_encoder *drm_enc,
                                                        u32 idle_timeout);
+/**
+ * dpu_encoder_get_linecount - get interface line count for the encoder.
+ * @drm_enc:    Pointer to previously created drm encoder structure
+ */
+int dpu_encoder_get_linecount(struct drm_encoder *drm_enc);
+
+/**
+ * dpu_encoder_get_frame_count - get interface frame count for the encoder.
+ * @drm_enc:    Pointer to previously created drm encoder structure
+ */
+int dpu_encoder_get_frame_count(struct drm_encoder *drm_enc);
 
 #endif /* __DPU_ENCODER_H__ */
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c 
b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index 374b0e8..ed636f1 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -14,6 +14,7 @@
 
 #include <drm/drm_crtc.h>
 #include <drm/drm_file.h>
+#include <drm/drm_vblank.h>
 
 #include "msm_drv.h"
 #include "msm_mmu.h"
@@ -1020,6 +1021,10 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
         */
        dev->mode_config.allow_fb_modifiers = true;
 
+       dev->max_vblank_count = 0xffffffff;
+       /* Disable vblank irqs aggressively for power-saving */
+       dev->vblank_disable_immediate = true;
+
        /*
         * _dpu_kms_drm_obj_init should create the DRM related objects
         * i.e. CRTCs, planes, encoders, connectors and so forth
-- 
2.7.4

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