[PATCH 06/14] drm/i915: add basic Haswell DP link train bits

Paulo Zanoni
2012-10-15T18:52:16Z

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

Previously, the DP register was used for everything. On Haswell, it
was split into DDI_BUF_CTL (which is the new intel_dp->DP register)
and DP_TP_CTL.

The logic behind this patch is based on a patch written by Shobhit
Kumar, but the way the code was written is very different.

Credits-to: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
---
drivers/gpu/drm/i915/i915_reg.h | 4 ++
drivers/gpu/drm/i915/intel_dp.c | 104 +++++++++++++++++++++++++++++++++++++---
2 files changed, 102 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 7ca8b7d..68ce163 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -4426,12 +4426,16 @@
#define DP_TP_CTL_LINK_TRAIN_MASK (7<<8)
#define DP_TP_CTL_LINK_TRAIN_PAT1 (0<<8)
#define DP_TP_CTL_LINK_TRAIN_PAT2 (1<<8)
+#define DP_TP_CTL_LINK_TRAIN_PAT3 (4<<8)
+#define DP_TP_CTL_LINK_TRAIN_IDLE (2<<8)
#define DP_TP_CTL_LINK_TRAIN_NORMAL (3<<8)
+#define DP_TP_CTL_SCRAMBLE_DISABLE (1<<7)

/* DisplayPort Transport Status */
#define DP_TP_STATUS_A 0x64044
#define DP_TP_STATUS_B 0x64144
#define DP_TP_STATUS(port) _PORT(port, DP_TP_STATUS_A, DP_TP_STATUS_B)
+#define DP_TP_STATUS_IDLE_DONE (1<<25)
#define DP_TP_STATUS_AUTOTRAIN_DONE (1<<12)

/* DDI Buffer Control */
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3fa71cd..b10f35b 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -1476,7 +1476,19 @@ intel_dp_pre_emphasis_max(struct intel_dp *intel_dp, uint8_t voltage_swing)
{
struct drm_device *dev = intel_dp->base.base.dev;

- if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
+ if (IS_HASWELL(dev)) {
+ switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
+ case DP_TRAIN_VOLTAGE_SWING_400:
+ return DP_TRAIN_PRE_EMPHASIS_9_5;
+ case DP_TRAIN_VOLTAGE_SWING_600:
+ return DP_TRAIN_PRE_EMPHASIS_6;
+ case DP_TRAIN_VOLTAGE_SWING_800:
+ return DP_TRAIN_PRE_EMPHASIS_3_5;
+ case DP_TRAIN_VOLTAGE_SWING_1200:
+ default:
+ return DP_TRAIN_PRE_EMPHASIS_0;
+ }
+ } else if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
case DP_TRAIN_VOLTAGE_SWING_400:
return DP_TRAIN_PRE_EMPHASIS_6;
@@ -1630,6 +1642,40 @@ intel_gen7_edp_signal_levels(uint8_t train_set)
}
}

+/* Gen7.5's (HSW) DP voltage swing and pre-emphasis control */
+static uint32_t
+intel_dp_signal_levels_hsw(uint8_t train_set)
+{
+ int signal_levels = train_set & (DP_TRAIN_VOLTAGE_SWING_MASK |
+ DP_TRAIN_PRE_EMPHASIS_MASK);
+ switch (signal_levels) {
+ case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_0:
+ return DDI_BUF_EMP_400MV_0DB_HSW;
+ case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_3_5:
+ return DDI_BUF_EMP_400MV_3_5DB_HSW;
+ case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_6:
+ return DDI_BUF_EMP_400MV_6DB_HSW;
+ case DP_TRAIN_VOLTAGE_SWING_400 | DP_TRAIN_PRE_EMPHASIS_9_5:
+ return DDI_BUF_EMP_400MV_9_5DB_HSW;
+
+ case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_0:
+ return DDI_BUF_EMP_600MV_0DB_HSW;
+ case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_3_5:
+ return DDI_BUF_EMP_600MV_3_5DB_HSW;
+ case DP_TRAIN_VOLTAGE_SWING_600 | DP_TRAIN_PRE_EMPHASIS_6:
+ return DDI_BUF_EMP_600MV_6DB_HSW;
+
+ case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_0:
+ return DDI_BUF_EMP_800MV_0DB_HSW;
+ case DP_TRAIN_VOLTAGE_SWING_800 | DP_TRAIN_PRE_EMPHASIS_3_5:
+ return DDI_BUF_EMP_800MV_3_5DB_HSW;
+ default:
+ DRM_DEBUG_KMS("Unsupported voltage swing/pre-emphasis level:"
+ "0x%x\n", signal_levels);
+ return DDI_BUF_EMP_400MV_0DB_HSW;
+ }
+}
+
static uint8_t
intel_get_lane_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
int lane)
@@ -1686,8 +1732,44 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
struct drm_device *dev = intel_dp->base.base.dev;
struct drm_i915_private *dev_priv = dev->dev_private;
int ret;
+ uint32_t temp;

- if (HAS_PCH_CPT(dev) && (IS_GEN7(dev) || !is_cpu_edp(intel_dp))) {
+ if (IS_HASWELL(dev)) {
+ temp = I915_READ(DP_TP_CTL(intel_dp->port));
+
+ if (dp_train_pat & DP_LINK_SCRAMBLING_DISABLE)
+ temp |= DP_TP_CTL_SCRAMBLE_DISABLE;
+ else
+ temp &= ~DP_TP_CTL_SCRAMBLE_DISABLE;
+
+ temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
+ switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
+ case DP_TRAINING_PATTERN_DISABLE:
+ temp |= DP_TP_CTL_LINK_TRAIN_IDLE;
+ I915_WRITE(DP_TP_CTL(intel_dp->port), temp);
+
+ if (wait_for((I915_READ(DP_TP_STATUS(intel_dp->port)) &
+ DP_TP_STATUS_IDLE_DONE) == 0, 1))
+ DRM_ERROR("Timed out waiting for DP idle patterns\n");
+
+ temp &= ~DP_TP_CTL_LINK_TRAIN_MASK;
+ temp |= DP_TP_CTL_LINK_TRAIN_NORMAL;
+
+ break;
+ case DP_TRAINING_PATTERN_1:
+ temp |= DP_TP_CTL_LINK_TRAIN_PAT1;
+ break;
+ case DP_TRAINING_PATTERN_2:
+ temp |= DP_TP_CTL_LINK_TRAIN_PAT2;
+ break;
+ case DP_TRAINING_PATTERN_3:
+ temp |= DP_TP_CTL_LINK_TRAIN_PAT3;
+ break;
+ }
+ I915_WRITE(DP_TP_CTL(intel_dp->port), temp);
+
+ } else if (HAS_PCH_CPT(dev) &&
+ (IS_GEN7(dev) || !is_cpu_edp(intel_dp))) {
dp_reg_value &= ~DP_LINK_TRAIN_MASK_CPT;

switch (dp_train_pat & DP_TRAINING_PATTERN_MASK) {
@@ -1774,8 +1856,11 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
uint8_t link_status[DP_LINK_STATUS_SIZE];
uint32_t signal_levels;

-
- if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
+ if (IS_HASWELL(dev)) {
+ signal_levels = intel_dp_signal_levels_hsw(
+ intel_dp->train_set[0]);
+ DP = (DP & ~DDI_BUF_EMP_MASK) | signal_levels;
+ } else if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
signal_levels = intel_gen7_edp_signal_levels(intel_dp->train_set[0]);
DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_IVB) | signal_levels;
} else if (IS_GEN6(dev) && is_cpu_edp(intel_dp)) {
@@ -1783,9 +1868,10 @@ intel_dp_start_link_train(struct intel_dp *intel_dp)
DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_SNB) | signal_levels;
} else {
signal_levels = intel_dp_signal_levels(intel_dp->train_set[0]);
- DRM_DEBUG_KMS("training pattern 1 signal levels %08x\n", signal_levels);
DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;
}
+ DRM_DEBUG_KMS("training pattern 1 signal levels %08x\n",
+ signal_levels);

if (!intel_dp_set_link_train(intel_dp, DP,
DP_TRAINING_PATTERN_1 |
@@ -1861,7 +1947,10 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
break;
}

- if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
+ if (IS_HASWELL(dev)) {
+ signal_levels = intel_dp_signal_levels_hsw(intel_dp->train_set[0]);
+ DP = (DP & ~DDI_BUF_EMP_MASK) | signal_levels;
+ } else if (IS_GEN7(dev) && is_cpu_edp(intel_dp) && !IS_VALLEYVIEW(dev)) {
signal_levels = intel_gen7_edp_signal_levels(intel_dp->train_set[0]);
DP = (DP & ~EDP_LINK_TRAIN_VOL_EMP_MASK_IVB) | signal_levels;
} else if (IS_GEN6(dev) && is_cpu_edp(intel_dp)) {
@@ -1908,6 +1997,9 @@ intel_dp_complete_link_train(struct intel_dp *intel_dp)
++tries;
}

+ if (channel_eq)
+ DRM_DEBUG_KMS("Channel EQ done. DP Training successfull\n");
+
intel_dp_set_link_train(intel_dp, DP, DP_TRAINING_PATTERN_DISABLE);
}

--
1.7.11.4