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drm/i915: add basic Haswell DP link train bits
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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>
[danvet: Fixup the logic error spotted by Jani Nikula.]
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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Paulo Zanoni authored and Daniel Vetter committed Oct 17, 2012
1 parent 068759b commit d6c0d72
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Showing 2 changed files with 102 additions and 6 deletions.
4 changes: 4 additions & 0 deletions drivers/gpu/drm/i915/i915_reg.h
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Original file line number Diff line number Diff line change
Expand Up @@ -4435,12 +4435,16 @@
#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 */
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104 changes: 98 additions & 6 deletions drivers/gpu/drm/i915/intel_dp.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1470,7 +1470,19 @@ 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;
Expand Down Expand Up @@ -1624,6 +1636,40 @@ 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)
Expand Down Expand Up @@ -1680,8 +1726,44 @@ 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), 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) {
Expand Down Expand Up @@ -1768,18 +1850,22 @@ 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)) {
signal_levels = intel_gen6_edp_signal_levels(intel_dp->train_set[0]);
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 |
Expand Down Expand Up @@ -1855,7 +1941,10 @@ 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)) {
Expand Down Expand Up @@ -1902,6 +1991,9 @@ 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);
}

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