Add return code checks to the DPCD transactions in the SW link training
Signed-off-by: Sean Paul <seanpaul@xxxxxxxxxxxx>
---
drivers/video/exynos/exynos_dp_core.c | 86 +++++++++++++++++++++-----------
1 files changed, 56 insertions(+), 30 deletions(-)
diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
index d55470e..44820f2 100644
--- a/drivers/video/exynos/exynos_dp_core.c
+++ b/drivers/video/exynos/exynos_dp_core.c
@@ -261,11 +261,10 @@ static void exynos_dp_set_lane_lane_pre_emphasis(struct exynos_dp_device *dp,
}
}
-static void exynos_dp_link_start(struct exynos_dp_device *dp)
+static int exynos_dp_link_start(struct exynos_dp_device *dp)
{
u8 buf[4];
- int lane;
- int lane_count;
+ int lane, lane_count, retval;
lane_count = dp->link_train.lane_count;
@@ -276,8 +275,10 @@ static void exynos_dp_link_start(struct exynos_dp_device *dp)
dp->link_train.cr_loop[lane] = 0;
/* Set sink to D0 (Sink Not Ready) mode. */
- exynos_dp_write_byte_to_dpcd(dp, DPCD_ADDR_SINK_POWER_STATE,
+ retval = exynos_dp_write_byte_to_dpcd(dp, DPCD_ADDR_SINK_POWER_STATE,
DPCD_SET_POWER_STATE_D0);
+ if (retval)
+ return retval;
/* Set link rate and count as you want to establish*/
exynos_dp_set_link_bandwidth(dp, dp->link_train.link_rate);
@@ -286,8 +287,10 @@ static void exynos_dp_link_start(struct exynos_dp_device *dp)
/* Setup RX configuration */
buf[0] = dp->link_train.link_rate;
buf[1] = dp->link_train.lane_count;
- exynos_dp_write_bytes_to_dpcd(dp, DPCD_ADDR_LINK_BW_SET,
+ retval = exynos_dp_write_bytes_to_dpcd(dp, DPCD_ADDR_LINK_BW_SET,
2, buf);
+ if (retval)
+ return retval;
/* Set TX pre-emphasis to minimum */
for (lane = 0; lane < lane_count; lane++)
@@ -306,9 +309,11 @@ static void exynos_dp_link_start(struct exynos_dp_device *dp)
for (lane = 0; lane < lane_count; lane++)
buf[lane] = DPCD_PRE_EMPHASIS_PATTERN2_LEVEL0 |
DPCD_VOLTAGE_SWING_PATTERN1_LEVEL0;
- exynos_dp_write_bytes_to_dpcd(dp,
+ retval = exynos_dp_write_bytes_to_dpcd(dp,
DPCD_ADDR_TRAINING_LANE0_SET,
lane_count, buf);
+
+ return retval;
}
static unsigned char exynos_dp_get_lane_status(u8 link_status[2], int lane)
@@ -430,8 +435,7 @@ static void exynos_dp_reduce_link_rate(struct exynos_dp_device *dp)
static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp)
{
u8 link_status[2];
- int lane;
- int lane_count;
+ int lane, lane_count, retval;
u8 adjust_request[2];
u8 voltage_swing;
@@ -442,17 +446,22 @@ static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp)
lane_count = dp->link_train.lane_count;
- exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
+ retval = exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
2, link_status);
+ if (retval)
+ return retval;
if (exynos_dp_clock_recovery_ok(link_status, lane_count) == 0) {
/* set training pattern 2 for EQ */
exynos_dp_set_training_pattern(dp, TRAINING_PTN2);
for (lane = 0; lane < lane_count; lane++) {
- exynos_dp_read_bytes_from_dpcd(dp,
+ retval = exynos_dp_read_bytes_from_dpcd(dp,
DPCD_ADDR_ADJUST_REQUEST_LANE0_1,
2, adjust_request);
+ if (retval)
+ return retval;
+
voltage_swing = exynos_dp_get_adjust_request_voltage(
adjust_request, lane);
pre_emphasis = exynos_dp_get_adjust_request_pre_emphasis(
@@ -472,15 +481,19 @@ static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp)
lane);
}
- exynos_dp_write_byte_to_dpcd(dp,
+ retval = exynos_dp_write_byte_to_dpcd(dp,
DPCD_ADDR_TRAINING_PATTERN_SET,
DPCD_SCRAMBLING_DISABLED |
DPCD_TRAINING_PATTERN_2);
+ if (retval)
+ return retval;
- exynos_dp_write_bytes_to_dpcd(dp,
+ retval = exynos_dp_write_bytes_to_dpcd(dp,
DPCD_ADDR_TRAINING_LANE0_SET,
lane_count,
dp->link_train.training_lane);
+ if (retval)
+ return retval;
dev_info(dp->dev, "Link Training Clock Recovery success\n");
dp->link_train.lt_state = EQUALIZER_TRAINING;
@@ -488,9 +501,12 @@ static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp)
for (lane = 0; lane < lane_count; lane++) {
training_lane = exynos_dp_get_lane_link_training(
dp, lane);
- exynos_dp_read_bytes_from_dpcd(dp,
+ retval = exynos_dp_read_bytes_from_dpcd(dp,
DPCD_ADDR_ADJUST_REQUEST_LANE0_1,
2, adjust_request);
+ if (retval)
+ return retval;
+
voltage_swing = exynos_dp_get_adjust_request_voltage(
adjust_request, lane);
pre_emphasis = exynos_dp_get_adjust_request_pre_emphasis(
@@ -527,13 +543,14 @@ static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp)
dp->link_train.training_lane[lane], lane);
}
- exynos_dp_write_bytes_to_dpcd(dp,
- DPCD_ADDR_TRAINING_LANE0_SET,
- lane_count,
- dp->link_train.training_lane);
+ retval = exynos_dp_write_bytes_to_dpcd(dp,
+ DPCD_ADDR_TRAINING_LANE0_SET, lane_count,
+ dp->link_train.training_lane);
+ if (retval)
+ return retval;
}
- return 0;
+ return retval;
reduce_link_rate:
exynos_dp_reduce_link_rate(dp);
@@ -544,8 +561,7 @@ static int exynos_dp_process_equalizer_training(struct exynos_dp_device *dp)
{
u8 link_status[2];
u8 link_align[3];
- int lane;
- int lane_count;
+ int lane, lane_count, retval;
u32 reg;
u8 adjust_request[2];
@@ -557,8 +573,10 @@ static int exynos_dp_process_equalizer_training(struct exynos_dp_device *dp)
lane_count = dp->link_train.lane_count;
- exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
+ retval = exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
2, link_status);
+ if (retval)
+ return retval;
if (exynos_dp_clock_recovery_ok(link_status, lane_count) == 0) {
link_align[0] = link_status[0];
@@ -569,9 +587,12 @@ static int exynos_dp_process_equalizer_training(struct exynos_dp_device *dp)
&link_align[2]);
for (lane = 0; lane < lane_count; lane++) {
- exynos_dp_read_bytes_from_dpcd(dp,
+ retval = exynos_dp_read_bytes_from_dpcd(dp,
DPCD_ADDR_ADJUST_REQUEST_LANE0_1,
2, adjust_request);
+ if (retval)
+ return retval;
+
voltage_swing = exynos_dp_get_adjust_request_voltage(
adjust_request, lane);
pre_emphasis = exynos_dp_get_adjust_request_pre_emphasis(
@@ -620,10 +641,12 @@ static int exynos_dp_process_equalizer_training(struct exynos_dp_device *dp)
dp->link_train.training_lane[lane],
lane);
- exynos_dp_write_bytes_to_dpcd(dp,
- DPCD_ADDR_TRAINING_LANE0_SET,
- lane_count,
- dp->link_train.training_lane);
+ retval = exynos_dp_write_bytes_to_dpcd(dp,
+ DPCD_ADDR_TRAINING_LANE0_SET,
+ lane_count,
+ dp->link_train.training_lane);
+ if (retval)
+ return retval;
}
} else {
goto reduce_link_rate;
@@ -701,16 +724,17 @@ static void exynos_dp_init_training(struct exynos_dp_device *dp,
static int exynos_dp_sw_link_training(struct exynos_dp_device *dp)
{
- int retval = 0;
- int training_finished = 0;
+ int retval = 0, training_finished = 0;
dp->link_train.lt_state = START;
/* Process here */
- while (!training_finished) {
+ while (!retval && !training_finished) {
switch (dp->link_train.lt_state) {
case START:
- exynos_dp_link_start(dp);
+ retval = exynos_dp_link_start(dp);
+ if (retval)
+ dev_err(dp->dev, "LT link start failed!\n");
break;
case CLOCK_RECOVERY:
retval = exynos_dp_process_clock_recovery(dp);
@@ -729,6 +753,8 @@ static int exynos_dp_sw_link_training(struct exynos_dp_device *dp)
return -EREMOTEIO;
}
}
+ if (retval)
+ dev_err(dp->dev, "eDP link training failed (%d)\n", retval);
return retval;
}
--
1.7.7.3
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