[PATCH 2/8] drm/i915: Don't pass *DP around to link training functions

Ander Conselvan de Oliveira
2015-09-08T12:28:09Z

It just makes the code more confusing, so just reference intel_dp_>DP
directly. The old behavior is preserved by saving the previous value of
DP in the stack and restoring the old value in case of failure.

--

I'm not sure the old behavior is correct, but to err in the side of
caution I tried not to change it.
---
drivers/gpu/drm/i915/intel_dp.c | 66 ++++++++++++++++++++---------------------
1 file changed, 33 insertions(+), 33 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3d19404..58efdca 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3600,7 +3600,6 @@ intel_dp_set_signal_levels(struct intel_dp *intel_dp, uint32_t *DP)

static bool
intel_dp_set_link_train(struct intel_dp *intel_dp,
- uint32_t *DP,
uint8_t dp_train_pat)
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -3609,9 +3608,9 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
uint8_t buf[sizeof(intel_dp->train_set) + 1];
int ret, len;

- _intel_dp_set_link_train(intel_dp, DP, dp_train_pat);
+ _intel_dp_set_link_train(intel_dp, &intel_dp->DP, dp_train_pat);

- I915_WRITE(intel_dp->output_reg, *DP);
+ I915_WRITE(intel_dp->output_reg, intel_dp->DP);
POSTING_READ(intel_dp->output_reg);

buf[0] = dp_train_pat;
@@ -3632,17 +3631,17 @@ intel_dp_set_link_train(struct intel_dp *intel_dp,
}

static bool
-intel_dp_reset_link_train(struct intel_dp *intel_dp, uint32_t *DP,
+intel_dp_reset_link_train(struct intel_dp *intel_dp,
uint8_t dp_train_pat)
{
if (!intel_dp->train_set_valid)
memset(intel_dp->train_set, 0, sizeof(intel_dp->train_set));
- intel_dp_set_signal_levels(intel_dp, DP);
- return intel_dp_set_link_train(intel_dp, DP, dp_train_pat);
+ intel_dp_set_signal_levels(intel_dp, &intel_dp->DP);
+ return intel_dp_set_link_train(intel_dp, dp_train_pat);
}

static bool
-intel_dp_update_link_train(struct intel_dp *intel_dp, uint32_t *DP,
+intel_dp_update_link_train(struct intel_dp *intel_dp,
const uint8_t link_status[DP_LINK_STATUS_SIZE])
{
struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);
@@ -3651,9 +3650,9 @@ intel_dp_update_link_train(struct intel_dp *intel_dp, uint32_t *DP,
int ret;

intel_get_adjust_train(intel_dp, link_status);
- intel_dp_set_signal_levels(intel_dp, DP);
+ intel_dp_set_signal_levels(intel_dp, &intel_dp->DP);

- I915_WRITE(intel_dp->output_reg, *DP);
+ I915_WRITE(intel_dp->output_reg, intel_dp->DP);
POSTING_READ(intel_dp->output_reg);

ret = drm_dp_dpcd_write(&intel_dp->aux, DP_TRAINING_LANE0_SET,
@@ -3694,7 +3693,7 @@ static void intel_dp_set_idle_link_train(struct intel_dp *intel_dp)
}

/* Enable corresponding port and start training pattern 1 */
-static void
+static bool
intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
{
struct drm_encoder *encoder = &dp_to_dig_port(intel_dp)->base.base;
@@ -3702,9 +3701,9 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
int i;
uint8_t voltage;
int voltage_tries, loop_tries;
- uint32_t DP = intel_dp->DP;
uint8_t link_config[2];
uint8_t link_bw, rate_select;
+ uint8_t link_status[DP_LINK_STATUS_SIZE];

if (HAS_DDI(dev))
intel_ddi_prepare_link_retrain(encoder);
@@ -3726,22 +3725,20 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
link_config[1] = DP_SET_ANSI_8B10B;
drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2);

- DP |= DP_PORT_EN;
+ intel_dp->DP |= DP_PORT_EN;

/* clock recovery */
- if (!intel_dp_reset_link_train(intel_dp, &DP,
+ if (!intel_dp_reset_link_train(intel_dp,
DP_TRAINING_PATTERN_1 |
DP_LINK_SCRAMBLING_DISABLE)) {
DRM_ERROR("failed to enable link training\n");
- return;
+ return false;
}

voltage = 0xff;
voltage_tries = 0;
loop_tries = 0;
for (;;) {
- uint8_t link_status[DP_LINK_STATUS_SIZE];
-
drm_dp_link_train_clock_recovery_delay(intel_dp->dpcd);
if (!intel_dp_get_link_status(intel_dp, link_status)) {
DRM_ERROR("failed to get link status\n");
@@ -3761,11 +3758,11 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
DRM_DEBUG_KMS("clock recovery not ok, reset");
/* clear the flag as we are not reusing train set */
intel_dp->train_set_valid = false;
- if (!intel_dp_reset_link_train(intel_dp, &DP,
+ if (!intel_dp_reset_link_train(intel_dp,
DP_TRAINING_PATTERN_1 |
DP_LINK_SCRAMBLING_DISABLE)) {
DRM_ERROR("failed to enable link training\n");
- return;
+ return false;
}
continue;
}
@@ -3780,7 +3777,7 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
DRM_ERROR("too many full retries, give up\n");
break;
}
- intel_dp_reset_link_train(intel_dp, &DP,
+ intel_dp_reset_link_train(intel_dp,
DP_TRAINING_PATTERN_1 |
DP_LINK_SCRAMBLING_DISABLE);
voltage_tries = 0;
@@ -3799,23 +3796,22 @@ intel_dp_link_training_clock_recovery(struct intel_dp *intel_dp)
voltage = intel_dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;

/* Update training set as requested by target */
- if (!intel_dp_update_link_train(intel_dp, &DP, link_status)) {
+ if (!intel_dp_update_link_train(intel_dp, link_status)) {
DRM_ERROR("failed to update link training\n");
break;
}
}

- intel_dp->DP = DP;
+ return drm_dp_clock_recovery_ok(link_status, intel_dp->lane_count);
}

-static void
+static bool
intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
{
struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
struct drm_device *dev = dig_port->base.base.dev;
bool channel_eq = false;
int tries, cr_tries;
- uint32_t DP = intel_dp->DP;
uint32_t training_pattern = DP_TRAINING_PATTERN_2;

/*
@@ -3834,11 +3830,11 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
DRM_ERROR("5.4 Gbps link rate without HBR2/TPS3 support\n");

/* channel equalization */
- if (!intel_dp_set_link_train(intel_dp, &DP,
+ if (!intel_dp_set_link_train(intel_dp,
training_pattern |
DP_LINK_SCRAMBLING_DISABLE)) {
DRM_ERROR("failed to start channel equalization\n");
- return;
+ return false;
}

tries = 0;
@@ -3863,7 +3859,7 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
intel_dp->lane_count)) {
intel_dp->train_set_valid = false;
intel_dp_link_training_clock_recovery(intel_dp);
- intel_dp_set_link_train(intel_dp, &DP,
+ intel_dp_set_link_train(intel_dp,
training_pattern |
DP_LINK_SCRAMBLING_DISABLE);
cr_tries++;
@@ -3880,7 +3876,7 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
if (tries > 5) {
intel_dp->train_set_valid = false;
intel_dp_link_training_clock_recovery(intel_dp);
- intel_dp_set_link_train(intel_dp, &DP,
+ intel_dp_set_link_train(intel_dp,
training_pattern |
DP_LINK_SCRAMBLING_DISABLE);
tries = 0;
@@ -3889,7 +3885,7 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)
}

/* Update training set as requested by target */
- if (!intel_dp_update_link_train(intel_dp, &DP, link_status)) {
+ if (!intel_dp_update_link_train(intel_dp, link_status)) {
DRM_ERROR("failed to update link training\n");
break;
}
@@ -3898,25 +3894,29 @@ intel_dp_link_training_channel_equalization(struct intel_dp *intel_dp)

intel_dp_set_idle_link_train(intel_dp);

- intel_dp->DP = DP;
-
if (channel_eq) {
intel_dp->train_set_valid = true;
DRM_DEBUG_KMS("Channel EQ done. DP Training successful\n");
+ return true;
+ } else {
+ return false;
}
}

void intel_dp_stop_link_train(struct intel_dp *intel_dp)
{
- intel_dp_set_link_train(intel_dp, &intel_dp->DP,
+ intel_dp_set_link_train(intel_dp,
DP_TRAINING_PATTERN_DISABLE);
}

void
intel_dp_start_link_train(struct intel_dp *intel_dp)
{
- intel_dp_link_training_clock_recovery(intel_dp);
- intel_dp_link_training_channel_equalization(intel_dp);
+ uint32_t DP = intel_dp->DP;
+
+ if (!intel_dp_link_training_clock_recovery(intel_dp) ||
+ !intel_dp_link_training_channel_equalization(intel_dp))
+ intel_dp->DP = DP;
}

static void
--
2.4.3