[PATCH 13/14] drm/i915: implement Haswell DP link train sequence

Paulo Zanoni
2012-10-15T18:52:31Z

From: Paulo Zanoni <paulo.r.zanoni@intel.com>

Previous patch "drm/i915: add basic Haswell DP link train bits"
implemented the basic structure to set the voltage levels and training
patterns. This patch adds the higher-level bits that are part of the
mode set sequence and hot plug.

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
drivers/gpu/drm/i915/intel_ddi.c | 53 ++++++++++++++++++++++++++++++++++++++--
drivers/gpu/drm/i915/intel_dp.c | 32 +++++++++++++++++++-----
drivers/gpu/drm/i915/intel_drv.h | 4 +++
3 files changed, 81 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
index 601ffc2..81cca48 100644
--- a/drivers/gpu/drm/i915/intel_ddi.c
+++ b/drivers/gpu/drm/i915/intel_ddi.c
@@ -1108,14 +1108,23 @@ void intel_ddi_disable_pipe_clock(struct intel_crtc *intel_crtc)

void intel_ddi_pre_enable(struct intel_encoder *intel_encoder)
{
- struct drm_crtc *crtc = intel_encoder->base.crtc;
- struct drm_i915_private *dev_priv = crtc->dev->dev_private;
+ struct drm_encoder *encoder = &intel_encoder->base;
+ struct drm_crtc *crtc = encoder->crtc;
+ struct drm_i915_private *dev_priv = encoder->dev->dev_private;
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
enum port port = intel_ddi_get_encoder_port(intel_encoder);

WARN_ON(intel_crtc->ddi_pll_sel == PORT_CLK_SEL_NONE);

I915_WRITE(PORT_CLK_SEL(port), intel_crtc->ddi_pll_sel);
+
+ if (intel_encoder->type == INTEL_OUTPUT_DISPLAYPORT) {
+ struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+
+ intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON);
+ intel_dp_start_link_train(intel_dp);
+ intel_dp_complete_link_train(intel_dp);
+ }
}

static void intel_wait_ddi_buf_idle(struct drm_i915_private *dev_priv,
@@ -1210,3 +1219,43 @@ void intel_ddi_pll_init(struct drm_device *dev)
if (val & LCPLL_PLL_DISABLE)
DRM_ERROR("LCPLL is disabled\n");
}
+
+void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder)
+{
+ struct intel_dp *intel_dp = enc_to_intel_dp(encoder);
+ struct drm_i915_private *dev_priv = encoder->dev->dev_private;
+ enum port port = intel_dp->port;
+ bool wait;
+ uint32_t val;
+
+ if (I915_READ(DP_TP_CTL(port)) & DP_TP_CTL_ENABLE) {
+ val = I915_READ(DDI_BUF_CTL(port));
+ if (val & DDI_BUF_CTL_ENABLE) {
+ val &= ~DDI_BUF_CTL_ENABLE;
+ I915_WRITE(DDI_BUF_CTL(port), val);
+ wait = true;
+ }
+
+ val = I915_READ(DP_TP_CTL(port));
+ val &= ~(DP_TP_CTL_ENABLE | DP_TP_CTL_LINK_TRAIN_MASK);
+ val |= DP_TP_CTL_LINK_TRAIN_PAT1;
+ I915_WRITE(DP_TP_CTL(port), val);
+ POSTING_READ(DP_TP_CTL(port));
+
+ if (wait)
+ intel_wait_ddi_buf_idle(dev_priv, port);
+ }
+
+ val = DP_TP_CTL_ENABLE | DP_TP_CTL_MODE_SST |
+ DP_TP_CTL_LINK_TRAIN_PAT1 | DP_TP_CTL_SCRAMBLE_DISABLE;
+ if (intel_dp->link_configuration[1] & DP_LANE_COUNT_ENHANCED_FRAME_EN)
+ val |= DP_TP_CTL_ENHANCED_FRAME_ENABLE;
+ I915_WRITE(DP_TP_CTL(port), val);
+ POSTING_READ(DP_TP_CTL(port));
+
+ intel_dp->DP |= DDI_BUF_CTL_ENABLE;
+ I915_WRITE(DDI_BUF_CTL(port), intel_dp->DP);
+ POSTING_READ(DDI_BUF_CTL(port));
+
+ udelay(600);
+}
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3a5fe2f..36687d9 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -102,8 +102,6 @@ bool intel_encoder_is_pch_edp(struct drm_encoder *encoder)
return is_pch_edp(intel_dp);
}

-static void intel_dp_start_link_train(struct intel_dp *intel_dp);
-static void intel_dp_complete_link_train(struct intel_dp *intel_dp);
static void intel_dp_link_down(struct intel_dp *intel_dp);

void
@@ -1266,7 +1264,7 @@ static void ironlake_edp_pll_off(struct intel_dp *intel_dp)
}

/* If the sink supports it, try to set the power state appropriately */
-static void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
+void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode)
{
int ret, i;

@@ -1854,16 +1852,20 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
}

/* Enable corresponding port and start training pattern 1 */
-static void
+void
intel_dp_start_link_train(struct intel_dp *intel_dp)
{
- struct drm_device *dev = intel_dp->base.base.dev;
+ struct drm_encoder *encoder = &intel_dp->base.base;
+ struct drm_device *dev = encoder->dev;
int i;
uint8_t voltage;
bool clock_recovery = false;
int voltage_tries, loop_tries;
uint32_t DP = intel_dp->DP;

+ if (IS_HASWELL(dev))
+ intel_ddi_prepare_link_retrain(encoder);
+
/* Write the link configuration data */
intel_dp_aux_native_write(intel_dp, DP_LINK_BW_SET,
intel_dp->link_configuration,
@@ -1949,7 +1951,7 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
intel_dp->DP = DP;
}

-static void
+void
intel_dp_complete_link_train(struct intel_dp *intel_dp)
{
struct drm_device *dev = intel_dp->base.base.dev;
@@ -2035,6 +2037,24 @@ intel_dp_link_down(struct intel_dp *intel_dp)
struct drm_i915_private *dev_priv = dev->dev_private;
uint32_t DP = intel_dp->DP;

+ /*
+ * DDI code has a strict mode set sequence and we should try to respect
+ * it, otherwise we might hang the machine in many different ways. So we
+ * really should be disabling the port only on a complete crtc_disable
+ * sequence. This function is just called under two conditions on DDI
+ * code:
+ * - Link train failed while doing crtc_enable, and on this case we
+ * really should respect the mode set sequence and wait for a
+ * crtc_disable.
+ * - Someone turned the monitor off and intel_dp_check_link_status
+ * called us. We don't need to disable the whole port on this case, so
+ * when someone turns the monitor on again,
+ * intel_ddi_prepare_link_retrain will take care of redoing the link
+ * train.
+ */
+ if (IS_HASWELL(dev))
+ return;
+
if (WARN_ON((I915_READ(intel_dp->output_reg) & DP_PORT_EN) == 0))
return;

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index d89d428..95cbd67 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -423,6 +423,9 @@ void
intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
struct drm_display_mode *adjusted_mode);
extern void intel_dp_init_link_config(struct intel_dp *intel_dp);
+extern void intel_dp_start_link_train(struct intel_dp *intel_dp);
+extern void intel_dp_complete_link_train(struct intel_dp *intel_dp);
+extern void intel_dp_sink_dpms(struct intel_dp *intel_dp, int mode);
extern bool intel_dpd_is_edp(struct drm_device *dev);
extern void intel_edp_link_config(struct intel_encoder *, int *, int *);
extern int intel_edp_target_clock(struct intel_encoder *,
@@ -599,5 +602,6 @@ extern void intel_ddi_pre_enable(struct intel_encoder *intel_encoder);
extern void intel_ddi_post_disable(struct intel_encoder *intel_encoder);
extern void intel_ddi_put_crtc_pll(struct drm_crtc *crtc);
extern void intel_ddi_set_pipe_settings(struct drm_crtc *crtc);
+extern void intel_ddi_prepare_link_retrain(struct drm_encoder *encoder);

#endif /* __INTEL_DRV_H__ */
--
1.7.11.4