[PATCH 07/10] drm/i915: extract common link_m_n helpers

[Daniel Vetter <daniel.vetter@ffwll.ch>]

Both the dp and fdi code use the exact same computations (ignore minor
differences in conversion between bits and bytes).

This makes it even more apparent that we have a _massive_ mess between
cpu transcoder/fdi link/pch transcoder and pch link settings. And also
that we have hilarious amounts of confusion between edp and dp
(despite that they're identical at a link level).

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_drv.h      | 13 ++++++++++++
 drivers/gpu/drm/i915/intel_display.c | 31 +++++++++-------------------
 drivers/gpu/drm/i915/intel_dp.c      | 39 +++---------------------------------
 3 files changed, 26 insertions(+), 57 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 9be7efd..a98cff0 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -101,6 +101,19 @@ struct intel_pch_pll {
 };
 #define I915_NUM_PLLS 2
 
+/* Used by dp and fdi links */
+struct intel_link_m_n {
+	uint32_t	tu;
+	uint32_t	gmch_m;
+	uint32_t	gmch_n;
+	uint32_t	link_m;
+	uint32_t	link_n;
+};
+
+void intel_link_compute_m_n(int bpp, int nlanes,
+			    int pixel_clock, int link_clock,
+			    struct intel_link_m_n *m_n);
+
 struct intel_ddi_plls {
 	int spll_refcount;
 	int wrpll1_refcount;
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 456acd6..9e13636 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -3954,16 +3954,8 @@ static int i830_get_display_clock_speed(struct drm_device *dev)
 	return 133000;
 }
 
-struct fdi_m_n {
-	u32        tu;
-	u32        gmch_m;
-	u32        gmch_n;
-	u32        link_m;
-	u32        link_n;
-};
-
 static void
-fdi_reduce_ratio(u32 *num, u32 *den)
+intel_reduce_ratio(uint32_t *num, uint32_t *den)
 {
 	while (*num > 0xffffff || *den > 0xffffff) {
 		*num >>= 1;
@@ -3971,20 +3963,18 @@ fdi_reduce_ratio(u32 *num, u32 *den)
 	}
 }
 
-static void
-ironlake_compute_m_n(int bits_per_pixel, int nlanes, int pixel_clock,
-		     int link_clock, struct fdi_m_n *m_n)
+void
+intel_link_compute_m_n(int bits_per_pixel, int nlanes,
+		       int pixel_clock, int link_clock,
+		       struct intel_link_m_n *m_n)
 {
-	m_n->tu = 64; /* default size */
-
-	/* BUG_ON(pixel_clock > INT_MAX / 36); */
+	m_n->tu = 64;
 	m_n->gmch_m = bits_per_pixel * pixel_clock;
 	m_n->gmch_n = link_clock * nlanes * 8;
-	fdi_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
-
+	intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
 	m_n->link_m = pixel_clock;
 	m_n->link_n = link_clock;
-	fdi_reduce_ratio(&m_n->link_m, &m_n->link_n);
+	intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
 }
 
 static inline bool intel_panel_use_ssc(struct drm_i915_private *dev_priv)
@@ -5098,7 +5088,7 @@ static void ironlake_set_m_n(struct drm_crtc *crtc,
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	enum transcoder cpu_transcoder = intel_crtc->cpu_transcoder;
 	struct intel_encoder *intel_encoder, *edp_encoder = NULL;
-	struct fdi_m_n m_n = {0};
+	struct intel_link_m_n m_n = {0};
 	int target_clock, pixel_multiplier, lane, link_bw;
 	bool is_dp = false, is_cpu_edp = false;
 
@@ -5156,8 +5146,7 @@ static void ironlake_set_m_n(struct drm_crtc *crtc,
 
 	if (pixel_multiplier > 1)
 		link_bw *= pixel_multiplier;
-	ironlake_compute_m_n(intel_crtc->bpp, lane, target_clock, link_bw,
-			     &m_n);
+	intel_link_compute_m_n(intel_crtc->bpp, lane, target_clock, link_bw, &m_n);
 
 	I915_WRITE(PIPE_DATA_M1(cpu_transcoder), TU_SIZE(m_n.tu) | m_n.gmch_m);
 	I915_WRITE(PIPE_DATA_N1(cpu_transcoder), m_n.gmch_n);
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index c308550..c5bd555 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -742,39 +742,6 @@ intel_dp_mode_fixup(struct drm_encoder *encoder,
 	return false;
 }
 
-struct intel_dp_m_n {
-	uint32_t	tu;
-	uint32_t	gmch_m;
-	uint32_t	gmch_n;
-	uint32_t	link_m;
-	uint32_t	link_n;
-};
-
-static void
-intel_reduce_ratio(uint32_t *num, uint32_t *den)
-{
-	while (*num > 0xffffff || *den > 0xffffff) {
-		*num >>= 1;
-		*den >>= 1;
-	}
-}
-
-static void
-intel_dp_compute_m_n(int bpp,
-		     int nlanes,
-		     int pixel_clock,
-		     int link_clock,
-		     struct intel_dp_m_n *m_n)
-{
-	m_n->tu = 64;
-	m_n->gmch_m = (pixel_clock * bpp) >> 3;
-	m_n->gmch_n = link_clock * nlanes;
-	intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
-	m_n->link_m = pixel_clock;
-	m_n->link_n = link_clock;
-	intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
-}
-
 void
 intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
 		 struct drm_display_mode *adjusted_mode)
@@ -785,7 +752,7 @@ intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
 	int lane_count = 4;
-	struct intel_dp_m_n m_n;
+	struct intel_link_m_n m_n;
 	int pipe = intel_crtc->pipe;
 	enum transcoder cpu_transcoder = intel_crtc->cpu_transcoder;
 
@@ -808,8 +775,8 @@ intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
 	 * the number of bytes_per_pixel post-LUT, which we always
 	 * set up for 8-bits of R/G/B, or 3 bytes total.
 	 */
-	intel_dp_compute_m_n(intel_crtc->bpp, lane_count,
-			     mode->clock, adjusted_mode->clock, &m_n);
+	intel_link_compute_m_n(intel_crtc->bpp, lane_count,
+			       mode->clock, adjusted_mode->clock, &m_n);
 
 	if (IS_HASWELL(dev)) {
 		I915_WRITE(PIPE_DATA_M1(cpu_transcoder),
-- 
1.7.11.7