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authorJingoo Han <jg1.han@samsung.com>2012-07-19 13:52:59 +0900
committerFlorian Tobias Schandinat <FlorianSchandinat@gmx.de>2012-08-23 12:57:18 +0000
commitd5c0eed01c0d6e316589578859d8d99aca2d3b06 (patch)
tree1ac22cd70d1eb877ba732834f75da845ab23f33c /drivers/video/exynos
parentc1c52848cef52e157468b8879fc3cae23b6f3a99 (diff)
downloadop-kernel-dev-d5c0eed01c0d6e316589578859d8d99aca2d3b06.zip
op-kernel-dev-d5c0eed01c0d6e316589578859d8d99aca2d3b06.tar.gz
video: exynos_dp: adjust voltage swing and pre-emphasis during Link Training
This patch adds adjustement for voltage swing and pre-emphasis during Link Training procedure. According to the DP specification, unless all the LANEx_CR_DONE bits are set, the transmitter must read the ADJUST_REQUEST_LANEx_x, increase the voltage swing according to the request, and update the TRAINING_LANEx_SET bytes to match the new voltage swing setting. Refer to the DP specification v1.1a, Section 3.5.1.3 Link Training. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Diffstat (limited to 'drivers/video/exynos')
-rw-r--r--drivers/video/exynos/exynos_dp_core.c282
-rw-r--r--drivers/video/exynos/exynos_dp_core.h2
2 files changed, 144 insertions, 140 deletions
diff --git a/drivers/video/exynos/exynos_dp_core.c b/drivers/video/exynos/exynos_dp_core.c
index c6c016a..9c0140f 100644
--- a/drivers/video/exynos/exynos_dp_core.c
+++ b/drivers/video/exynos/exynos_dp_core.c
@@ -260,7 +260,7 @@ 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)
{
- u8 buf[5];
+ u8 buf[4];
int lane;
int lane_count;
@@ -295,10 +295,10 @@ static void exynos_dp_link_start(struct exynos_dp_device *dp)
exynos_dp_set_training_pattern(dp, TRAINING_PTN1);
/* Set RX training pattern */
- buf[0] = DPCD_SCRAMBLING_DISABLED |
- DPCD_TRAINING_PATTERN_1;
exynos_dp_write_byte_to_dpcd(dp,
- DPCD_ADDR_TRAINING_PATTERN_SET, buf[0]);
+ DPCD_ADDR_TRAINING_PATTERN_SET,
+ DPCD_SCRAMBLING_DISABLED |
+ DPCD_TRAINING_PATTERN_1);
for (lane = 0; lane < lane_count; lane++)
buf[lane] = DPCD_PRE_EMPHASIS_PATTERN2_LEVEL0 |
@@ -308,7 +308,7 @@ static void exynos_dp_link_start(struct exynos_dp_device *dp)
lane_count, buf);
}
-static unsigned char exynos_dp_get_lane_status(u8 link_status[6], int lane)
+static unsigned char exynos_dp_get_lane_status(u8 link_status[2], int lane)
{
int shift = (lane & 1) * 4;
u8 link_value = link_status[lane>>1];
@@ -316,7 +316,7 @@ static unsigned char exynos_dp_get_lane_status(u8 link_status[6], int lane)
return (link_value >> shift) & 0xf;
}
-static int exynos_dp_clock_recovery_ok(u8 link_status[6], int lane_count)
+static int exynos_dp_clock_recovery_ok(u8 link_status[2], int lane_count)
{
int lane;
u8 lane_status;
@@ -329,22 +329,23 @@ static int exynos_dp_clock_recovery_ok(u8 link_status[6], int lane_count)
return 0;
}
-static int exynos_dp_channel_eq_ok(u8 link_status[6], int lane_count)
+static int exynos_dp_channel_eq_ok(u8 link_align[3], int lane_count)
{
int lane;
u8 lane_align;
u8 lane_status;
- lane_align = link_status[2];
+ lane_align = link_align[2];
if ((lane_align & DPCD_INTERLANE_ALIGN_DONE) == 0)
return -EINVAL;
for (lane = 0; lane < lane_count; lane++) {
- lane_status = exynos_dp_get_lane_status(link_status, lane);
+ lane_status = exynos_dp_get_lane_status(link_align, lane);
lane_status &= DPCD_CHANNEL_EQ_BITS;
if (lane_status != DPCD_CHANNEL_EQ_BITS)
return -EINVAL;
}
+
return 0;
}
@@ -417,69 +418,17 @@ static unsigned int exynos_dp_get_lane_link_training(
static void exynos_dp_reduce_link_rate(struct exynos_dp_device *dp)
{
- if (dp->link_train.link_rate == LINK_RATE_2_70GBPS) {
- /* set to reduced bit rate */
- dp->link_train.link_rate = LINK_RATE_1_62GBPS;
- dev_err(dp->dev, "set to bandwidth %.2x\n",
- dp->link_train.link_rate);
- dp->link_train.lt_state = START;
- } else {
- exynos_dp_training_pattern_dis(dp);
- /* set enhanced mode if available */
- exynos_dp_set_enhanced_mode(dp);
- dp->link_train.lt_state = FAILED;
- }
-}
-
-static void exynos_dp_get_adjust_train(struct exynos_dp_device *dp,
- u8 adjust_request[2])
-{
- int lane;
- int lane_count;
- u8 voltage_swing;
- u8 pre_emphasis;
- u8 training_lane;
+ exynos_dp_training_pattern_dis(dp);
+ exynos_dp_set_enhanced_mode(dp);
- lane_count = dp->link_train.lane_count;
- for (lane = 0; lane < lane_count; lane++) {
- voltage_swing = exynos_dp_get_adjust_request_voltage(
- adjust_request, lane);
- pre_emphasis = exynos_dp_get_adjust_request_pre_emphasis(
- adjust_request, lane);
- training_lane = DPCD_VOLTAGE_SWING_SET(voltage_swing) |
- DPCD_PRE_EMPHASIS_SET(pre_emphasis);
-
- if (voltage_swing == VOLTAGE_LEVEL_3 ||
- pre_emphasis == PRE_EMPHASIS_LEVEL_3) {
- training_lane |= DPCD_MAX_SWING_REACHED;
- training_lane |= DPCD_MAX_PRE_EMPHASIS_REACHED;
- }
- dp->link_train.training_lane[lane] = training_lane;
- }
-}
-
-static int exynos_dp_check_max_cr_loop(struct exynos_dp_device *dp,
- u8 voltage_swing)
-{
- int lane;
- int lane_count;
-
- lane_count = dp->link_train.lane_count;
- for (lane = 0; lane < lane_count; lane++) {
- if (voltage_swing == VOLTAGE_LEVEL_3 ||
- dp->link_train.cr_loop[lane] == MAX_CR_LOOP)
- return -EINVAL;
- }
- return 0;
+ dp->link_train.lt_state = FAILED;
}
static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp)
{
- u8 data;
- u8 link_status[6];
+ u8 link_status[2];
int lane;
int lane_count;
- u8 buf[5];
u8 adjust_request[2];
u8 voltage_swing;
@@ -488,98 +437,152 @@ static int exynos_dp_process_clock_recovery(struct exynos_dp_device *dp)
usleep_range(100, 101);
- exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
- 6, link_status);
lane_count = dp->link_train.lane_count;
+ exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
+ 2, link_status);
+
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);
- adjust_request[0] = link_status[4];
- adjust_request[1] = link_status[5];
+ for (lane = 0; lane < lane_count; lane++) {
+ exynos_dp_read_bytes_from_dpcd(dp,
+ DPCD_ADDR_ADJUST_REQUEST_LANE0_1,
+ 2, adjust_request);
+ voltage_swing = exynos_dp_get_adjust_request_voltage(
+ adjust_request, lane);
+ pre_emphasis = exynos_dp_get_adjust_request_pre_emphasis(
+ adjust_request, lane);
+ training_lane = DPCD_VOLTAGE_SWING_SET(voltage_swing) |
+ DPCD_PRE_EMPHASIS_SET(pre_emphasis);
- exynos_dp_get_adjust_train(dp, adjust_request);
+ if (voltage_swing == VOLTAGE_LEVEL_3)
+ training_lane |= DPCD_MAX_SWING_REACHED;
+ if (pre_emphasis == PRE_EMPHASIS_LEVEL_3)
+ training_lane |= DPCD_MAX_PRE_EMPHASIS_REACHED;
- buf[0] = DPCD_SCRAMBLING_DISABLED |
- DPCD_TRAINING_PATTERN_2;
- exynos_dp_write_byte_to_dpcd(dp,
- DPCD_ADDR_TRAINING_PATTERN_SET,
- buf[0]);
+ dp->link_train.training_lane[lane] = training_lane;
- for (lane = 0; lane < lane_count; lane++) {
exynos_dp_set_lane_link_training(dp,
dp->link_train.training_lane[lane],
lane);
- buf[lane] = dp->link_train.training_lane[lane];
- exynos_dp_write_byte_to_dpcd(dp,
- DPCD_ADDR_TRAINING_LANE0_SET + lane,
- buf[lane]);
}
- dp->link_train.lt_state = EQUALIZER_TRAINING;
- } else {
- exynos_dp_read_byte_from_dpcd(dp,
- DPCD_ADDR_ADJUST_REQUEST_LANE0_1,
- &data);
- adjust_request[0] = data;
- exynos_dp_read_byte_from_dpcd(dp,
- DPCD_ADDR_ADJUST_REQUEST_LANE2_3,
- &data);
- adjust_request[1] = data;
+ exynos_dp_write_byte_to_dpcd(dp,
+ DPCD_ADDR_TRAINING_PATTERN_SET,
+ DPCD_SCRAMBLING_DISABLED |
+ DPCD_TRAINING_PATTERN_2);
+
+ exynos_dp_write_bytes_to_dpcd(dp,
+ DPCD_ADDR_TRAINING_LANE0_SET,
+ lane_count,
+ dp->link_train.training_lane);
+ dev_info(dp->dev, "Link Training Clock Recovery success\n");
+ dp->link_train.lt_state = EQUALIZER_TRAINING;
+ } else {
for (lane = 0; lane < lane_count; lane++) {
training_lane = exynos_dp_get_lane_link_training(
dp, lane);
+ exynos_dp_read_bytes_from_dpcd(dp,
+ DPCD_ADDR_ADJUST_REQUEST_LANE0_1,
+ 2, adjust_request);
voltage_swing = exynos_dp_get_adjust_request_voltage(
adjust_request, lane);
pre_emphasis = exynos_dp_get_adjust_request_pre_emphasis(
adjust_request, lane);
- if ((DPCD_VOLTAGE_SWING_GET(training_lane) == voltage_swing) &&
- (DPCD_PRE_EMPHASIS_GET(training_lane) == pre_emphasis))
- dp->link_train.cr_loop[lane]++;
- dp->link_train.training_lane[lane] = training_lane;
- }
- if (exynos_dp_check_max_cr_loop(dp, voltage_swing) != 0) {
- exynos_dp_reduce_link_rate(dp);
- } else {
- exynos_dp_get_adjust_train(dp, adjust_request);
+ if (voltage_swing == VOLTAGE_LEVEL_3 ||
+ pre_emphasis == PRE_EMPHASIS_LEVEL_3) {
+ dev_err(dp->dev, "voltage or pre emphasis reached max level\n");
+ goto reduce_link_rate;
+ }
- for (lane = 0; lane < lane_count; lane++) {
- exynos_dp_set_lane_link_training(dp,
- dp->link_train.training_lane[lane],
- lane);
- buf[lane] = dp->link_train.training_lane[lane];
- exynos_dp_write_byte_to_dpcd(dp,
- DPCD_ADDR_TRAINING_LANE0_SET + lane,
- buf[lane]);
+ if ((DPCD_VOLTAGE_SWING_GET(training_lane) ==
+ voltage_swing) &&
+ (DPCD_PRE_EMPHASIS_GET(training_lane) ==
+ pre_emphasis)) {
+ dp->link_train.cr_loop[lane]++;
+ if (dp->link_train.cr_loop[lane] == MAX_CR_LOOP) {
+ dev_err(dp->dev, "CR Max loop\n");
+ goto reduce_link_rate;
+ }
}
+
+ training_lane = DPCD_VOLTAGE_SWING_SET(voltage_swing) |
+ DPCD_PRE_EMPHASIS_SET(pre_emphasis);
+
+ if (voltage_swing == VOLTAGE_LEVEL_3)
+ training_lane |= DPCD_MAX_SWING_REACHED;
+ if (pre_emphasis == PRE_EMPHASIS_LEVEL_3)
+ training_lane |= DPCD_MAX_PRE_EMPHASIS_REACHED;
+
+ dp->link_train.training_lane[lane] = training_lane;
+
+ exynos_dp_set_lane_link_training(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);
}
return 0;
+
+reduce_link_rate:
+ exynos_dp_reduce_link_rate(dp);
+ return -EIO;
}
static int exynos_dp_process_equalizer_training(struct exynos_dp_device *dp)
{
- u8 link_status[6];
+ u8 link_status[2];
+ u8 link_align[3];
int lane;
int lane_count;
- u8 buf[5];
u32 reg;
u8 adjust_request[2];
+ u8 voltage_swing;
+ u8 pre_emphasis;
+ u8 training_lane;
usleep_range(400, 401);
- exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
- 6, link_status);
lane_count = dp->link_train.lane_count;
+ exynos_dp_read_bytes_from_dpcd(dp, DPCD_ADDR_LANE0_1_STATUS,
+ 2, link_status);
+
if (exynos_dp_clock_recovery_ok(link_status, lane_count) == 0) {
- adjust_request[0] = link_status[4];
- adjust_request[1] = link_status[5];
+ link_align[0] = link_status[0];
+ link_align[1] = link_status[1];
+
+ exynos_dp_read_byte_from_dpcd(dp,
+ DPCD_ADDR_LANE_ALIGN_STATUS_UPDATED,
+ &link_align[2]);
+
+ for (lane = 0; lane < lane_count; lane++) {
+ exynos_dp_read_bytes_from_dpcd(dp,
+ DPCD_ADDR_ADJUST_REQUEST_LANE0_1,
+ 2, adjust_request);
+ voltage_swing = exynos_dp_get_adjust_request_voltage(
+ adjust_request, lane);
+ pre_emphasis = exynos_dp_get_adjust_request_pre_emphasis(
+ adjust_request, lane);
+ training_lane = DPCD_VOLTAGE_SWING_SET(voltage_swing) |
+ DPCD_PRE_EMPHASIS_SET(pre_emphasis);
+
+ if (voltage_swing == VOLTAGE_LEVEL_3)
+ training_lane |= DPCD_MAX_SWING_REACHED;
+ if (pre_emphasis == PRE_EMPHASIS_LEVEL_3)
+ training_lane |= DPCD_MAX_PRE_EMPHASIS_REACHED;
+
+ dp->link_train.training_lane[lane] = training_lane;
+ }
if (exynos_dp_channel_eq_ok(link_status, lane_count) == 0) {
/* traing pattern Set to Normal */
@@ -596,39 +599,42 @@ static int exynos_dp_process_equalizer_training(struct exynos_dp_device *dp)
dp->link_train.lane_count = reg;
dev_dbg(dp->dev, "final lane count = %.2x\n",
dp->link_train.lane_count);
+
/* set enhanced mode if available */
exynos_dp_set_enhanced_mode(dp);
-
dp->link_train.lt_state = FINISHED;
} else {
/* not all locked */
dp->link_train.eq_loop++;
if (dp->link_train.eq_loop > MAX_EQ_LOOP) {
- exynos_dp_reduce_link_rate(dp);
- } else {
- exynos_dp_get_adjust_train(dp, adjust_request);
-
- for (lane = 0; lane < lane_count; lane++) {
- exynos_dp_set_lane_link_training(dp,
- dp->link_train.training_lane[lane],
- lane);
- buf[lane] = dp->link_train.training_lane[lane];
- exynos_dp_write_byte_to_dpcd(dp,
- DPCD_ADDR_TRAINING_LANE0_SET + lane,
- buf[lane]);
- }
+ dev_err(dp->dev, "EQ Max loop\n");
+ goto reduce_link_rate;
}
+
+ for (lane = 0; lane < lane_count; lane++)
+ exynos_dp_set_lane_link_training(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);
}
} else {
- exynos_dp_reduce_link_rate(dp);
+ goto reduce_link_rate;
}
return 0;
+
+reduce_link_rate:
+ exynos_dp_reduce_link_rate(dp);
+ return -EIO;
}
static void exynos_dp_get_max_rx_bandwidth(struct exynos_dp_device *dp,
- u8 *bandwidth)
+ u8 *bandwidth)
{
u8 data;
@@ -641,7 +647,7 @@ static void exynos_dp_get_max_rx_bandwidth(struct exynos_dp_device *dp,
}
static void exynos_dp_get_max_rx_lane_count(struct exynos_dp_device *dp,
- u8 *lane_count)
+ u8 *lane_count)
{
u8 data;
@@ -693,13 +699,7 @@ 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;
-
- /* Turn off unnecessary lane */
- if (dp->link_train.lane_count == 1)
- exynos_dp_set_analog_power_down(dp, CH1_BLOCK, 1);
-
- training_finished = 0;
+ int training_finished = 0;
dp->link_train.lt_state = START;
@@ -710,10 +710,14 @@ static int exynos_dp_sw_link_training(struct exynos_dp_device *dp)
exynos_dp_link_start(dp);
break;
case CLOCK_RECOVERY:
- exynos_dp_process_clock_recovery(dp);
+ retval = exynos_dp_process_clock_recovery(dp);
+ if (retval)
+ dev_err(dp->dev, "LT CR failed!\n");
break;
case EQUALIZER_TRAINING:
- exynos_dp_process_equalizer_training(dp);
+ retval = exynos_dp_process_equalizer_training(dp);
+ if (retval)
+ dev_err(dp->dev, "LT EQ failed!\n");
break;
case FINISHED:
training_finished = 1;
diff --git a/drivers/video/exynos/exynos_dp_core.h b/drivers/video/exynos/exynos_dp_core.h
index 8526e54..44c11e1 100644
--- a/drivers/video/exynos/exynos_dp_core.h
+++ b/drivers/video/exynos/exynos_dp_core.h
@@ -144,7 +144,7 @@ void exynos_dp_disable_scrambling(struct exynos_dp_device *dp);
#define DPCD_ADDR_TRAINING_PATTERN_SET 0x0102
#define DPCD_ADDR_TRAINING_LANE0_SET 0x0103
#define DPCD_ADDR_LANE0_1_STATUS 0x0202
-#define DPCD_ADDR_LANE_ALIGN__STATUS_UPDATED 0x0204
+#define DPCD_ADDR_LANE_ALIGN_STATUS_UPDATED 0x0204
#define DPCD_ADDR_ADJUST_REQUEST_LANE0_1 0x0206
#define DPCD_ADDR_ADJUST_REQUEST_LANE2_3 0x0207
#define DPCD_ADDR_TEST_REQUEST 0x0218
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