[PATCH v3] drm/i915: Generalize drain latency computation

Gajanan Bhat
2014-08-06T14:56:01Z

Modify drain latency computation to use it for any plane. Same function can be
used for primary, cursor and sprite planes.

v2: Adressed review comments by Imre and Ville.
- Moved clock round up in separate patch
- Added WARN check for clock and pixel size
- Simplified bit masking
- Use cursor_base instead of reg read

v3: Changed to bitwise shorthand operator for plane_dl assignment.

Signed-off-by: Gajanan Bhat <gajanan.bhat@intel.com>
---
drivers/gpu/drm/i915/i915_reg.h | 1 +
drivers/gpu/drm/i915/intel_pm.c | 87 ++++++++++++++++++++++-----------------
2 files changed, 51 insertions(+), 37 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 187f862..08916df 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4009,6 +4009,7 @@ enum punit_power_well {
#define DDL_PLANE_PRECISION_64 (1<<7)
#define DDL_PLANE_PRECISION_32 (0<<7)
#define DDL_PLANE_SHIFT 0
+#define DRAIN_LATENCY_MASK 0x7f

/* FIFO watermark sizes etc */
#define G4X_FIFO_LINE_SIZE 64
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index ba8dfeb..cabea4b 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -1277,33 +1277,24 @@ static bool g4x_compute_srwm(struct drm_device *dev,
display, cursor);
}

-static bool vlv_compute_drain_latency(struct drm_device *dev,
- int plane,
- int *plane_prec_mult,
- int *plane_dl,
- int *cursor_prec_mult,
- int *cursor_dl)
+static bool vlv_compute_drain_latency(struct drm_crtc *crtc,
+ int pixel_size,
+ int *prec_mult,
+ int *drain_latency)
{
- struct drm_crtc *crtc;
- int clock, pixel_size;
int entries;
+ int clock = to_intel_crtc(crtc)->config.adjusted_mode.crtc_clock;

- crtc = intel_get_crtc_for_plane(dev, plane);
- if (!intel_crtc_active(crtc))
+ if (WARN(clock == 0, "Pixel clock is zero!\n"))
return false;

- clock = to_intel_crtc(crtc)->config.adjusted_mode.crtc_clock;
- pixel_size = crtc->primary->fb->bits_per_pixel / 8; /* BPP */
+ if (WARN(pixel_size == 0, "Pixel size is zero!\n"))
+ return false;

entries = (clock / 1000) * pixel_size;
- *plane_prec_mult = (entries > 128) ?
- DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
- *plane_dl = (64 * (*plane_prec_mult) * 4) / entries;
-
- entries = (clock / 1000) * 4; /* BPP is always 4 for cursor */
- *cursor_prec_mult = (entries > 128) ?
- DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
- *cursor_dl = (64 * (*cursor_prec_mult) * 4) / entries;
+ *prec_mult = (entries > 128) ? DRAIN_LATENCY_PRECISION_64 :
+ DRAIN_LATENCY_PRECISION_32;
+ *drain_latency = (64 * (*prec_mult) * 4) / entries;

return true;
}
@@ -1318,24 +1309,46 @@ static bool vlv_compute_drain_latency(struct drm_device *dev,

static void vlv_update_drain_latency(struct drm_crtc *crtc)
{
- struct drm_device *dev = crtc->dev;
- struct drm_i915_private *dev_priv = dev->dev_private;
- enum pipe pipe = to_intel_crtc(crtc)->pipe;
- int plane_prec, plane_dl;
- int cursor_prec, cursor_dl;
- int plane_prec_mult, cursor_prec_mult;
-
- if (vlv_compute_drain_latency(dev, pipe, &plane_prec_mult, &plane_dl,
- &cursor_prec_mult, &cursor_dl)) {
- cursor_prec = (cursor_prec_mult == DRAIN_LATENCY_PRECISION_64) ?
- DDL_CURSOR_PRECISION_64 : DDL_CURSOR_PRECISION_32;
- plane_prec = (plane_prec_mult == DRAIN_LATENCY_PRECISION_64) ?
- DDL_PLANE_PRECISION_64 : DDL_PLANE_PRECISION_32;
-
- I915_WRITE(VLV_DDL(pipe), cursor_prec |
- (cursor_dl << DDL_CURSOR_SHIFT) |
- plane_prec | (plane_dl << DDL_PLANE_SHIFT));
+ struct drm_i915_private *dev_priv = crtc->dev->dev_private;
+ struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+ int pixel_size;
+ int drain_latency;
+ enum pipe pipe = intel_crtc->pipe;
+ int plane_prec, prec_mult, plane_dl;
+
+ plane_dl = I915_READ(VLV_DDL(pipe)) & ~(DDL_PLANE_PRECISION_64 |
+ DRAIN_LATENCY_MASK | DDL_CURSOR_PRECISION_64 |
+ (DRAIN_LATENCY_MASK << DDL_CURSOR_SHIFT));
+
+ if (!intel_crtc_active(crtc)) {
+ I915_WRITE(VLV_DDL(pipe), plane_dl);
+ return;
+ }
+
+ /* Primary plane Drain Latency */
+ pixel_size = crtc->primary->fb->bits_per_pixel / 8; /* BPP */
+ if (vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, &drain_latency)) {
+ plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
+ DDL_PLANE_PRECISION_64 :
+ DDL_PLANE_PRECISION_32;
+ plane_dl |= plane_prec | drain_latency;
}
+
+ /* Cursor Drain Latency
+ * BPP is always 4 for cursor
+ */
+ pixel_size = 4;
+
+ /* Program cursor DL only if it is enabled */
+ if (intel_crtc->cursor_base &&
+ vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, &drain_latency)) {
+ plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
+ DDL_CURSOR_PRECISION_64 :
+ DDL_CURSOR_PRECISION_32;
+ plane_dl |= plane_prec | (drain_latency << DDL_CURSOR_SHIFT);
+ }
+
+ I915_WRITE(VLV_DDL(pipe), plane_dl);
}

#define single_plane_enabled(mask) is_power_of_2(mask)
--
1.7.9.5