[PATCH 3/4] drm/i915: hw state readout support for fdi m/n

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

We want to use the fdi m/n values to easily compute the adjusted mode
dotclock on pch ports. Hence make sure the values stored in the pipe
config are always reliable.

v2: Fixup FDI TU readout.

v3: Rebase on top of moved cpu_transcoder.

Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_reg.h      |  1 +
 drivers/gpu/drm/i915/intel_display.c | 25 +++++++++++++++++++++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 9093d66..a017120 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -3524,6 +3524,7 @@
 #define _PIPEA_DATA_M1           (dev_priv->info->display_mmio_offset + 0x60030)
 #define  TU_SIZE(x)             (((x)-1) << 25) /* default size 64 */
 #define  TU_SIZE_MASK           0x7e000000
+#define  TU_SIZE_SHIFT		25
 #define  PIPE_DATA_M1_OFFSET    0
 #define _PIPEA_DATA_N1           (dev_priv->info->display_mmio_offset + 0x60034)
 #define  PIPE_DATA_N1_OFFSET    0
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 7216ba5..a023dc2 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -5799,6 +5799,22 @@ static int ironlake_crtc_mode_set(struct drm_crtc *crtc,
 	return ret;
 }
 
+static void ironlake_get_fdi_m_n_config(struct intel_crtc *crtc,
+					struct intel_crtc_config *pipe_config)
+{
+	struct drm_device *dev = crtc->base.dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	enum transcoder transcoder = pipe_config->cpu_transcoder;
+
+	pipe_config->fdi_m_n.link_m = I915_READ(PIPE_LINK_M1(transcoder));
+	pipe_config->fdi_m_n.link_n = I915_READ(PIPE_LINK_N1(transcoder));
+	pipe_config->fdi_m_n.gmch_m = I915_READ(PIPE_DATA_M1(transcoder))
+					& ~TU_SIZE_MASK;
+	pipe_config->fdi_m_n.gmch_n = I915_READ(PIPE_DATA_N1(transcoder));
+	pipe_config->fdi_m_n.tu = ((I915_READ(PIPE_DATA_M1(transcoder))
+				   & TU_SIZE_MASK) >> TU_SIZE_SHIFT) + 1;
+}
+
 static bool ironlake_get_pipe_config(struct intel_crtc *crtc,
 				     struct intel_crtc_config *pipe_config)
 {
@@ -5815,6 +5831,8 @@ static bool ironlake_get_pipe_config(struct intel_crtc *crtc,
 
 		tmp = I915_READ(FDI_RX_CTL(crtc->pipe));
 		pipe_config->fdi_lanes = ((tmp >> 19) & 0x3) + 1;
+
+		ironlake_get_fdi_m_n_config(crtc, pipe_config);
 	}
 
 	return true;
@@ -5960,6 +5978,8 @@ static bool haswell_get_pipe_config(struct intel_crtc *crtc,
 
 		tmp = I915_READ(FDI_RX_CTL(PIPE_A));
 		pipe_config->fdi_lanes = ((tmp >> 19) & 0x3) + 1;
+
+		ironlake_get_fdi_m_n_config(crtc, pipe_config);
 	}
 
 	return true;
@@ -7941,6 +7961,11 @@ intel_pipe_config_compare(struct intel_crtc_config *current_config,
 
 	PIPE_CONF_CHECK_I(has_pch_encoder);
 	PIPE_CONF_CHECK_I(fdi_lanes);
+	PIPE_CONF_CHECK_I(fdi_m_n.gmch_m);
+	PIPE_CONF_CHECK_I(fdi_m_n.gmch_n);
+	PIPE_CONF_CHECK_I(fdi_m_n.link_m);
+	PIPE_CONF_CHECK_I(fdi_m_n.link_n);
+	PIPE_CONF_CHECK_I(fdi_m_n.tu);
 
 #undef PIPE_CONF_CHECK_I
 
-- 
1.7.11.7