video_display: Add Xilinx LogiCore DP TX

Add a driver for the Xilinx LogiCORE DisplayPort IP core, which is a
pure DP transmitter core for Xiling FPGA (no display capabilities).

Signed-off-by: Mario Six <mario.six@gdsys.cc>

1 files changed, 2296 insertions, 0 deletions

diff --git a/drivers/video/logicore_dp_tx.c b/drivers/video/logicore_dp_tx.c
new file mode 100644
index 0000000000..84fafe4341
--- /dev/null
+++ b/drivers/video/logicore_dp_tx.c
@@ -0,0 +1,2296 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * logicore_dp_tx.c
+ *
+ * Driver for XILINX LogiCore DisplayPort v6.1 TX (Source)
+ * based on Xilinx dp_v3_1 driver sources, updated to dp_v4_0
+ *
+ * (C) Copyright 2016
+ * Dirk Eibach,  Guntermann & Drunck GmbH, dirk.eibach@gdsys.cc
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <display.h>
+#include <dm.h>
+#include <errno.h>
+
+#include "axi.h"
+#include "logicore_dp_dpcd.h"
+#include "logicore_dp_tx.h"
+#include "logicore_dp_tx_regif.h"
+
+/* Default AXI clock frequency value */
+#define S_AXI_CLK_DEFAULT 100000000
+
+/* Default DP phy clock value */
+#define PHY_CLOCK_SELECT_DEFAULT PHY_CLOCK_SELECT_540GBPS
+
+/* The maximum voltage swing level is 3 */
+#define MAXIMUM_VS_LEVEL 3
+/* The maximum pre-emphasis level is 3 */
+#define MAXIMUM_PE_LEVEL 3
+
+/* Error out if an AUX request yields a defer reply more than 50 times */
+#define AUX_MAX_DEFER_COUNT 50
+/* Error out if an AUX request times out more than 50 times awaiting a reply */
+#define AUX_MAX_TIMEOUT_COUNT 50
+/* Error out if checking for a connected device times out more than 50 times */
+#define IS_CONNECTED_MAX_TIMEOUT_COUNT 50
+
+/**
+ * enum link_training_states - States for link training state machine
+ * @TS_CLOCK_RECOVERY:       State for clock recovery
+ * @TS_CHANNEL_EQUALIZATION: State for channel equalization
+ * @TS_ADJUST_LINK_RATE:     State where link rate is reduced in reaction to
+ *			     failed link training
+ * @TS_ADJUST_LANE_COUNT:    State where lane count is reduced in reaction to
+ *			     failed link training
+ * @TS_FAILURE:              State of link training failure
+ * @TS_SUCCESS::             State for successfully completed link training
+ */
+enum link_training_states {
+	TS_CLOCK_RECOVERY,
+	TS_CHANNEL_EQUALIZATION,
+	TS_ADJUST_LINK_RATE,
+	TS_ADJUST_LANE_COUNT,
+	TS_FAILURE,
+	TS_SUCCESS
+};
+
+/**
+ * struct aux_transaction - Description of an AUX channel transaction
+ * @cmd_code:  Command code of the transaction
+ * @num_bytes: The number of bytes in the transaction's payload data
+ * @address:   The DPCD address of the transaction
+ * @data:      Payload data of the AUX channel transaction
+ */
+struct aux_transaction {
+	u16 cmd_code;
+	u8 num_bytes;
+	u32 address;
+	u8 *data;
+};
+
+/**
+ * struct main_stream_attributes - Main stream attributes
+ * @pixel_clock_hz: Pixel clock of the stream (in Hz)
+ * @misc_0:                    Miscellaneous stream attributes 0 as specified
+ *			       by the DisplayPort 1.2 specification
+ * @misc_1:                    Miscellaneous stream attributes 1 as specified
+ *			       by the DisplayPort 1.2 specification
+ * @n_vid:                     N value for the video stream
+ * @m_vid:                     M value used to recover the video clock from the
+ *			       link clock
+ * @user_pixel_width:          Width of the user data input port
+ * @data_per_lane:             Used to translate the number of pixels per line
+ *			       to the native internal 16-bit datapath
+ * @avg_bytes_per_tu:          Average number of bytes per transfer unit,
+ *			       scaled up by a factor of 1000
+ * @transfer_unit_size:        Size of the transfer unit in the framing logic
+ *			       In MST mode, this is also the number of time
+ *			       slots that are alloted in the payload ID table
+ * @init_wait:                 Number of initial wait cycles at the start of a
+ *			       new line by the framing logic
+ * @bits_per_color:            Bits per color component
+ * @component_format:          The component format currently in use by the
+ *			       video stream
+ * @dynamic_range:             The dynamic range currently in use by the video
+ *			       stream
+ * @y_cb_cr_colorimetry:       The YCbCr colorimetry currently in use by the
+ *			       video stream
+ * @synchronous_clock_mode:    Synchronous clock mode is currently in use by
+ *			       the video stream
+ * @override_user_pixel_width: If set to 1, the value stored for
+ *			       user_pixel_width will be used as the pixel width
+ * @h_start:                   Horizontal blank start (pixels)
+ * @h_active:                  Horizontal active resolution (pixels)
+ * @h_sync_width:              Horizontal sync width (pixels)
+ * @h_total:                   Horizontal total (pixels)
+ * @h_sync_polarity:           Horizontal sync polarity (0=neg|1=pos)
+ * @v_start:                   Vertical blank start (in lines)
+ * @v_active:                  Vertical active resolution (lines)
+ * @v_sync_width:              Vertical sync width (lines)
+ * @v_total:                   Vertical total (lines)
+ * @v_sync_polarity:           Vertical sync polarity (0=neg|1=pos)
+ *
+ * All porch parameters have been removed, because our videodata is
+ * hstart/vstart based, and there is no benefit in keeping the porches
+ */
+struct main_stream_attributes {
+	u32 pixel_clock_hz;
+	u32 misc_0;
+	u32 misc_1;
+	u32 n_vid;
+	//u32 m_vid;
+	u32 user_pixel_width;
+	u32 data_per_lane;
+	u32 avg_bytes_per_tu;
+	u32 transfer_unit_size;
+	u32 init_wait;
+	u32 bits_per_color;
+	u8 component_format;
+	u8 dynamic_range;
+	u8 y_cb_cr_colorimetry;
+	u8 synchronous_clock_mode;
+	u8 override_user_pixel_width;
+	u32 h_start;
+	u16 h_active;
+	u16 h_sync_width;
+	u16 h_total;
+	bool h_sync_polarity;
+	u32 v_start;
+	u16 v_active;
+	u16 v_sync_width;
+	u16 v_total;
+	bool v_sync_polarity;
+};
+
+/**
+ * struct link_config - Description of link configuration
+ * @lane_count:                    Currently selected lane count for this link
+ * @link_rate:                     Currently selected link rate for this link
+ * @scrambler_en:                  Flag to determine whether the scrambler is
+ *				   enabled for this link
+ * @enhanced_framing_mode:         Flag to determine whether enhanced framing
+ *				   mode is active for this link
+ * @max_lane_count:                Maximum lane count for this link
+ * @max_link_rate:                 Maximum link rate for this link
+ * @support_enhanced_framing_mode: Flag to indicate whether the link supports
+ *				   enhanced framing mode
+ * @vs_level:                      Voltage swing for each lane
+ * @pe_level:                      Pre-emphasis/cursor level for each lane
+ */
+struct link_config {
+	u8 lane_count;
+	u8 link_rate;
+	bool scrambler_en;
+	bool enhanced_framing_mode;
+	u8 max_lane_count;
+	u8 max_link_rate;
+	bool support_enhanced_framing_mode;
+	u8 vs_level;
+	u8 pe_level;
+};
+
+/**
+ * struct dp_tx - Private data structure of LogiCore DP TX devices
+ *
+ * @base:                   Address of register base of device
+ * @s_axi_clk:              The AXI clock frequency in Hz
+ * @train_adaptive:         Use adaptive link trainig (i.e. successively reduce
+ *			    link rate and/or lane count) for this device
+ * @max_link_rate:          Maximum link rate for this device
+ * @max_lane_count:         Maximum lane count for this device
+ * @dpcd_rx_caps:           RX device's status registers, see below
+ * @lane_status_ajd_reqs:   Lane status and adjustment requests information for
+ *			    this device
+ * @link_config:            The link configuration for this device
+ * @main_stream_attributes: MSA set for this device
+ *
+ * dpcd_rx_caps is a raw read of the RX device's status registers. The first 4
+ * bytes correspond to the lane status associated with clock recovery, channel
+ * equalization, symbol lock, and interlane alignment. The remaining 2 bytes
+ * represent the pre-emphasis and voltage swing level adjustments requested by
+ * the RX device.
+ */
+struct dp_tx {
+	u32 base;
+	u32 s_axi_clk;
+	bool train_adaptive;
+	u8 max_link_rate;
+	u8 max_lane_count;
+	u8 dpcd_rx_caps[16];
+	u8 lane_status_ajd_reqs[6];
+	struct link_config link_config;
+	struct main_stream_attributes main_stream_attributes;
+};
+
+/*
+ * Internal API
+ */
+
+/**
+ * get_reg() - Read a register of a LogiCore DP TX device
+ * @dev: The LogiCore DP TX device in question
+ * @reg: The offset of the register to read
+ *
+ * Return: The read register value
+ */
+static u32 get_reg(struct udevice *dev, u32 reg)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u32 value = 0;
+	int res;
+
+	/* TODO(mario.six@gdsys.cc): error handling */
+	res = axi_read(dev->parent, dp_tx->base + reg, &value, AXI_SIZE_32);
+	if (res < 0)
+		printf("%s() failed; res = %d\n", __func__, res);
+
+	return value;
+}
+
+/**
+ * set_reg() - Write a register of a LogiCore DP TX device
+ * @dev:   The LogiCore DP TX device in question
+ * @reg:   The offset of the register to write
+ * @value: The value to write to the register
+ */
+static void set_reg(struct udevice *dev, u32 reg, u32 value)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+
+	axi_write(dev->parent, dp_tx->base + reg, &value, AXI_SIZE_32);
+}
+
+/**
+ * is_connected() - Check if there is a connected RX device
+ * @dev: The LogiCore DP TX device in question
+ *
+ * The Xilinx original calls msleep_interruptible at least once, ignoring
+ * status.
+ *
+ * Return: true if a connected RX device was detected, false otherwise
+ */
+static bool is_connected(struct udevice *dev)
+{
+	u8 retries = 0;
+
+	do {
+		int status = get_reg(dev, REG_INTERRUPT_SIG_STATE) &
+			     INTERRUPT_SIG_STATE_HPD_STATE_MASK;
+		if (status)
+			return true;
+
+		udelay(1000);
+	} while (retries++ < IS_CONNECTED_MAX_TIMEOUT_COUNT);
+
+	return false;
+}
+
+/**
+ * wait_phy_ready() - Wait for the DisplayPort PHY to come out of reset
+ * @dev:  The LogiCore DP TX device in question
+ * @mask: Bit mask specifying which bit in the status register should be waited
+ *	  for
+ *
+ * Return: 0 if wait succeeded, -ve if error occurred
+ */
+static int wait_phy_ready(struct udevice *dev, u32 mask)
+{
+	u16 timeout = 20000;
+	u32 phy_status;
+
+	/* Wait until the PHY is ready. */
+	do {
+		phy_status = get_reg(dev, REG_PHY_STATUS) & mask;
+
+		/* Protect against an infinite loop. */
+		if (!timeout--)
+			return -ETIMEDOUT;
+
+		udelay(20);
+	} while (phy_status != mask);
+
+	return 0;
+}
+
+/* AUX channel access */
+
+/**
+ * aux_wait_ready() -  Wait until another request is no longer in progress
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Return: 0 if wait succeeded, -ve if error occurred
+ */
+static int aux_wait_ready(struct udevice *dev)
+{
+	int status;
+	u32 timeout = 100;
+
+	/* Wait until the DisplayPort TX core is ready. */
+	do {
+		status = get_reg(dev, REG_INTERRUPT_SIG_STATE);
+
+		/* Protect against an infinite loop. */
+		if (!timeout--)
+			return -ETIMEDOUT;
+		udelay(20);
+	} while (status & REPLY_STATUS_REPLY_IN_PROGRESS_MASK);
+
+	return 0;
+}
+
+/**
+ * aux_wait_reply() - Wait for reply on AUX channel
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Wait for a reply indicating that the most recent AUX request
+ * has been received by the RX device.
+ *
+ * Return: 0 if wait succeeded, -ve if error occurred
+ */
+static int aux_wait_reply(struct udevice *dev)
+{
+	u32 timeout = 100;
+
+	while (timeout > 0) {
+		int status = get_reg(dev, REG_REPLY_STATUS);
+
+		/* Check for error. */
+		if (status & REPLY_STATUS_REPLY_ERROR_MASK)
+			return -ETIMEDOUT;
+
+		/* Check for a reply. */
+		if ((status & REPLY_STATUS_REPLY_RECEIVED_MASK) &&
+		    !(status &
+		      REPLY_STATUS_REQUEST_IN_PROGRESS_MASK) &&
+		    !(status &
+		      REPLY_STATUS_REPLY_IN_PROGRESS_MASK)) {
+			return 0;
+		}
+
+		timeout--;
+		udelay(20);
+	}
+
+	return -ETIMEDOUT;
+}
+
+/**
+ * aux_request_send() - Send request on the AUX channel
+ * @dev:     The LogiCore DP TX device in question
+ * @request: The request to send
+ *
+ * Submit the supplied AUX request to the RX device over the AUX
+ * channel by writing the command, the destination address, (the write buffer
+ * for write commands), and the data size to the DisplayPort TX core.
+ *
+ * This is the lower-level sending routine, which is called by aux_request().
+ *
+ * Return: 0 if request was sent successfully, -ve on error
+ */
+static int aux_request_send(struct udevice *dev,
+			    struct aux_transaction *request)
+{
+	u32 timeout_count;
+	int status;
+	u8 index;
+
+	/* Ensure that any pending AUX transactions have completed. */
+	timeout_count = 0;
+	do {
+		status = get_reg(dev, REG_REPLY_STATUS);
+
+		udelay(20);
+		timeout_count++;
+		if (timeout_count >= AUX_MAX_TIMEOUT_COUNT)
+			return -ETIMEDOUT;
+	} while ((status & REPLY_STATUS_REQUEST_IN_PROGRESS_MASK) ||
+		 (status & REPLY_STATUS_REPLY_IN_PROGRESS_MASK));
+
+	set_reg(dev, REG_AUX_ADDRESS, request->address);
+
+	if (request->cmd_code == AUX_CMD_WRITE ||
+	    request->cmd_code == AUX_CMD_I2C_WRITE ||
+	    request->cmd_code == AUX_CMD_I2C_WRITE_MOT) {
+		/* Feed write data into the DisplayPort TX core's write FIFO. */
+		for (index = 0; index < request->num_bytes; index++) {
+			set_reg(dev,
+				REG_AUX_WRITE_FIFO, request->data[index]);
+		}
+	}
+
+	/* Submit the command and the data size. */
+	set_reg(dev, REG_AUX_CMD,
+		((request->cmd_code << AUX_CMD_SHIFT) |
+		 ((request->num_bytes - 1) &
+		  AUX_CMD_NBYTES_TRANSFER_MASK)));
+
+	/* Check for a reply from the RX device to the submitted request. */
+	status = aux_wait_reply(dev);
+	if (status)
+		/* Waiting for a reply timed out. */
+		return -ETIMEDOUT;
+
+	/* Analyze the reply. */
+	status = get_reg(dev, REG_AUX_REPLY_CODE);
+	if (status == AUX_REPLY_CODE_DEFER ||
+	    status == AUX_REPLY_CODE_I2C_DEFER) {
+		/* The request was deferred. */
+		return -EAGAIN;
+	} else if ((status == AUX_REPLY_CODE_NACK) ||
+		   (status == AUX_REPLY_CODE_I2C_NACK)) {
+		/* The request was not acknowledged. */
+		return -EIO;
+	}
+
+	/* The request was acknowledged. */
+
+	if (request->cmd_code == AUX_CMD_READ ||
+	    request->cmd_code == AUX_CMD_I2C_READ ||
+	    request->cmd_code == AUX_CMD_I2C_READ_MOT) {
+		/* Wait until all data has been received. */
+		timeout_count = 0;
+		do {
+			status = get_reg(dev, REG_REPLY_DATA_COUNT);
+
+			udelay(100);
+			timeout_count++;
+			if (timeout_count >= AUX_MAX_TIMEOUT_COUNT)
+				return -ETIMEDOUT;
+		} while (status != request->num_bytes);
+
+		/* Obtain the read data from the reply FIFO. */
+		for (index = 0; index < request->num_bytes; index++)
+			request->data[index] = get_reg(dev, REG_AUX_REPLY_DATA);
+	}
+
+	return 0;
+}
+
+/**
+ * aux_request() - Submit request on the AUX channel
+ * @dev:     The LogiCore DP TX device in question
+ * @request: The request to submit
+ *
+ * Submit the supplied AUX request to the RX device over the AUX
+ * channel. If waiting for a reply times out, or if the DisplayPort TX core
+ * indicates that the request was deferred, the request is sent again (up to a
+ * maximum specified by AUX_MAX_DEFER_COUNT|AUX_MAX_TIMEOUT_COUNT).
+ *
+ * Return: 0 if request was submitted successfully, -ve on error
+ */
+static int aux_request(struct udevice *dev, struct aux_transaction *request)
+{
+	u32 defer_count = 0;
+	u32 timeout_count = 0;
+
+	while ((defer_count < AUX_MAX_DEFER_COUNT) &&
+	       (timeout_count < AUX_MAX_TIMEOUT_COUNT)) {
+		int status = aux_wait_ready(dev);
+
+		if (status) {
+			/* The RX device isn't ready yet. */
+			timeout_count++;
+			continue;
+		}
+
+		status = aux_request_send(dev, request);
+		if (status == -EAGAIN) {
+			/* The request was deferred. */
+			defer_count++;
+		} else if (status == -ETIMEDOUT) {
+			/* Waiting for a reply timed out. */
+			timeout_count++;
+		} else {
+			/*
+			 * -EIO indicates that the request was NACK'ed,
+			 * 0 indicates that the request was ACK'ed.
+			 */
+			return status;
+		}
+
+		udelay(100);
+	}
+
+	/* The request was not successfully received by the RX device. */
+	return -ETIMEDOUT;
+}
+
+/**
+ * aux_common() - Common (read/write) AUX communication transmission
+ * @dev:       The LogiCore DP TX device in question
+ * @cmd_type:  Command code of the transaction
+ * @address:   The DPCD address of the transaction
+ * @num_bytes: Number of bytes in the payload data
+ * @data:      The payload data of the AUX command
+ *
+ * Common sequence of submitting an AUX command for AUX read, AUX write,
+ * I2C-over-AUX read, and I2C-over-AUX write transactions. If required, the
+ * reads and writes are split into multiple requests, each acting on a maximum
+ * of 16 bytes.
+ *
+ * Return: 0 if OK, -ve on error
+ */
+static int aux_common(struct udevice *dev, u32 cmd_type, u32 address,
+		      u32 num_bytes, u8 *data)
+{
+	struct aux_transaction request;
+	u32 bytes_left;
+
+	/*
+	 * Set the start address for AUX transactions. For I2C transactions,
+	 * this is the address of the I2C bus.
+	 */
+	request.address = address;
+
+	bytes_left = num_bytes;
+	while (bytes_left) {
+		int status;
+
+		request.cmd_code = cmd_type;
+
+		if (cmd_type == AUX_CMD_READ ||
+		    cmd_type == AUX_CMD_WRITE) {
+			/* Increment address for normal AUX transactions. */
+			request.address = address + (num_bytes - bytes_left);
+		}
+
+		/* Increment the pointer to the supplied data buffer. */
+		request.data = &data[num_bytes - bytes_left];
+
+		request.num_bytes = (bytes_left > 16) ? 16 : bytes_left;
+		bytes_left -= request.num_bytes;
+
+		if (cmd_type == AUX_CMD_I2C_READ && bytes_left) {
+			/*
+			 * Middle of a transaction I2C read request. Override
+			 * the command code that was set to cmd_type.
+			 */
+			request.cmd_code = AUX_CMD_I2C_READ_MOT;
+		} else if ((cmd_type == AUX_CMD_I2C_WRITE) && bytes_left) {
+			/*
+			 * Middle of a transaction I2C write request. Override
+			 * the command code that was set to cmd_type.
+			 */
+			request.cmd_code = AUX_CMD_I2C_WRITE_MOT;
+		}
+
+		status = aux_request(dev, &request);
+		if (status)
+			return status;
+	}
+
+	return 0;
+}
+
+/**
+ * aux_read() - Issue AUX read request
+ * @dev:           The LogiCore DP TX device in question
+ * @dpcd_address:  The DPCD address to read from
+ * @bytes_to_read: Number of bytes to read
+ * @read_data:     Buffer to receive the read data
+ *
+ * Issue a read request over the AUX channel that will read from the RX
+ * device's DisplayPort Configuration data (DPCD) address space. The read
+ * message will be divided into multiple transactions which read a maximum of
+ * 16 bytes each.
+ *
+ * Return: 0 if read operation was successful, -ve on error
+ */
+static int aux_read(struct udevice *dev, u32 dpcd_address, u32 bytes_to_read,
+		    void *read_data)
+{
+	int status;
+
+	if (!is_connected(dev))
+		return -ENODEV;
+
+	/* Send AUX read transaction. */
+	status = aux_common(dev, AUX_CMD_READ, dpcd_address,
+			    bytes_to_read, (u8 *)read_data);
+
+	return status;
+}
+
+/**
+ * aux_write() - Issue AUX write request
+ * @dev:            The LogiCore DP TX device in question
+ * @dpcd_address:   The DPCD address to write to
+ * @bytes_to_write: Number of bytes to write
+ * @write_data:     Buffer containig data to be written
+ *
+ * Issue a write request over the AUX channel that will write to
+ * the RX device's DisplayPort Configuration data (DPCD) address space. The
+ * write message will be divided into multiple transactions which write a
+ * maximum of 16 bytes each.
+ *
+ * Return: 0 if write operation was successful, -ve on error
+ */
+static int aux_write(struct udevice *dev, u32 dpcd_address, u32 bytes_to_write,
+		     void *write_data)
+{
+	int status;
+
+	if (!is_connected(dev))
+		return -ENODEV;
+
+	/* Send AUX write transaction. */
+	status = aux_common(dev, AUX_CMD_WRITE, dpcd_address,
+			    bytes_to_write, (u8 *)write_data);
+
+	return status;
+}
+
+/* Core initialization */
+
+/**
+ * initialize() - Initialize a LogiCore DP TX device
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Return: Always 0
+ */
+static int initialize(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u32 val;
+	u32 phy_config;
+	unsigned int k;
+
+	/* place the PHY (and GTTXRESET) into reset. */
+	phy_config = get_reg(dev, REG_PHY_CONFIG);
+	set_reg(dev, REG_PHY_CONFIG, phy_config | PHY_CONFIG_GT_ALL_RESET_MASK);
+
+	/* reset the video streams and AUX logic. */
+	set_reg(dev, REG_SOFT_RESET,
+		SOFT_RESET_VIDEO_STREAM_ALL_MASK |
+		SOFT_RESET_AUX_MASK);
+
+	/* disable the DisplayPort TX core. */
+	set_reg(dev, REG_ENABLE, 0);
+
+	/* set the clock divider. */
+	val = get_reg(dev, REG_AUX_CLK_DIVIDER);
+	val &= ~AUX_CLK_DIVIDER_VAL_MASK;
+	val |= dp_tx->s_axi_clk / 1000000;
+	set_reg(dev, REG_AUX_CLK_DIVIDER, val);
+
+	/* set the DisplayPort TX core's clock speed. */
+	set_reg(dev, REG_PHY_CLOCK_SELECT, PHY_CLOCK_SELECT_DEFAULT);
+
+	/* bring the PHY (and GTTXRESET) out of reset. */
+	set_reg(dev, REG_PHY_CONFIG,
+		phy_config & ~PHY_CONFIG_GT_ALL_RESET_MASK);
+
+	/* enable the DisplayPort TX core. */
+	set_reg(dev, REG_ENABLE, 1);
+
+	/* Unmask Hot-Plug-Detect (HPD) interrupts. */
+	set_reg(dev, REG_INTERRUPT_MASK,
+		~INTERRUPT_MASK_HPD_PULSE_DETECTED_MASK &
+		~INTERRUPT_MASK_HPD_EVENT_MASK &
+		~INTERRUPT_MASK_HPD_IRQ_MASK);
+
+	for (k = 0; k < 4; k++) {
+		/* Disable pre-cursor levels. */
+		set_reg(dev, REG_PHY_PRECURSOR_LANE_0 + 4 * k, 0);
+
+		/* Write default voltage swing levels to the TX registers. */
+		set_reg(dev, REG_PHY_VOLTAGE_DIFF_LANE_0 + 4 * k, 0);
+
+		/* Write default pre-emphasis levels to the TX registers. */
+		set_reg(dev, REG_PHY_POSTCURSOR_LANE_0 + 4 * k, 0);
+	}
+
+	return 0;
+}
+
+/**
+ * is_link_rate_valid() - Check if given link rate is valif for device
+ * @dev:       The LogiCore DP TX device in question
+ * @link_rate: The link rate to be checked for validity
+ *
+ * Return: true if he supplied link rate is valid, false otherwise
+ */
+static bool is_link_rate_valid(struct udevice *dev, u8 link_rate)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	bool valid = true;
+
+	if (link_rate != LINK_BW_SET_162GBPS &&
+	    link_rate != LINK_BW_SET_270GBPS &&
+	    link_rate != LINK_BW_SET_540GBPS)
+		valid = false;
+	else if (link_rate > dp_tx->link_config.max_link_rate)
+		valid = false;
+
+	return valid;
+}
+
+/**
+ * is_lane_count_valid() - Check if given lane count is valif for device
+ * @dev:        The LogiCore DP TX device in question
+ * @lane_count: The lane count to be checked for validity
+ *
+ * Return: true if he supplied lane count is valid, false otherwise
+ */
+static bool is_lane_count_valid(struct udevice *dev, u8 lane_count)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	bool valid = true;
+
+	if (lane_count != LANE_COUNT_SET_1 &&
+	    lane_count != LANE_COUNT_SET_2 &&
+	    lane_count != LANE_COUNT_SET_4)
+		valid = false;
+	else if (lane_count > dp_tx->link_config.max_lane_count)
+		valid = false;
+
+	return valid;
+}
+
+/**
+ * get_rx_capabilities() - Check if capabilities of RX device are valid for TX
+ *			   device
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Return: 0 if the capabilities of the RX device are valid for the TX device,
+ *	   -ve if not, of an error occurred during capability determination
+ */
+static int get_rx_capabilities(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u8 rx_max_link_rate;
+	u8 rx_max_lane_count;
+
+	if (!is_connected(dev))
+		return -ENODEV;
+
+	status = aux_read(dev, DPCD_RECEIVER_CAP_FIELD_START, 16,
+			  dp_tx->dpcd_rx_caps);
+	if (status)
+		return -EIO;
+
+	rx_max_link_rate = dp_tx->dpcd_rx_caps[DPCD_MAX_LINK_RATE];
+	rx_max_lane_count = dp_tx->dpcd_rx_caps[DPCD_MAX_LANE_COUNT] &
+			    DPCD_MAX_LANE_COUNT_MASK;
+
+	dp_tx->link_config.max_link_rate =
+		(rx_max_link_rate > dp_tx->max_link_rate) ?
+		dp_tx->max_link_rate : rx_max_link_rate;
+	if (!is_link_rate_valid(dev, rx_max_link_rate))
+		return -EINVAL;
+
+	dp_tx->link_config.max_lane_count =
+		(rx_max_lane_count > dp_tx->max_lane_count) ?
+		dp_tx->max_lane_count : rx_max_lane_count;
+	if (!is_lane_count_valid(dev, rx_max_lane_count))
+		return -EINVAL;
+
+	dp_tx->link_config.support_enhanced_framing_mode =
+		dp_tx->dpcd_rx_caps[DPCD_MAX_LANE_COUNT] &
+		DPCD_ENHANCED_FRAME_SUPPORT_MASK;
+
+	return 0;
+}
+
+/**
+ * enable_main_link() - Switch on main link for a device
+ * @dev: The LogiCore DP TX device in question
+ */
+static void enable_main_link(struct udevice *dev)
+{
+	/* reset the scrambler. */
+	set_reg(dev, REG_FORCE_SCRAMBLER_RESET, 0x1);
+
+	/* enable the main stream. */
+	set_reg(dev, REG_ENABLE_MAIN_STREAM, 0x1);
+}
+
+/**
+ * disable_main_link() - Switch off main link for a device
+ * @dev: The LogiCore DP TX device in question
+ */
+static void disable_main_link(struct udevice *dev)
+{
+	/* reset the scrambler. */
+	set_reg(dev, REG_FORCE_SCRAMBLER_RESET, 0x1);
+
+	/* Disable the main stream. */
+	set_reg(dev, REG_ENABLE_MAIN_STREAM, 0x0);
+}
+
+/**
+ * reset_dp_phy() - Reset a device
+ * @dev:   The LogiCore DP TX device in question
+ * @reset: Bit mask determining which bits in the device's config register
+ *	   should be set for the reset
+ */
+static void reset_dp_phy(struct udevice *dev, u32 reset)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u32 val;
+
+	set_reg(dev, REG_ENABLE, 0x0);
+
+	val = get_reg(dev, REG_PHY_CONFIG);
+
+	/* Apply reset. */
+	set_reg(dev, REG_PHY_CONFIG, val | reset);
+
+	/* Remove reset. */
+	set_reg(dev, REG_PHY_CONFIG, val);
+
+	/* Wait for the PHY to be ready. */
+	wait_phy_ready(dev, phy_status_lanes_ready_mask(dp_tx->max_lane_count));
+
+	set_reg(dev, REG_ENABLE, 0x1);
+}
+
+/**
+ * set_enhanced_frame_mode() - Enable/Disable enhanced frame mode
+ * @dev:    The LogiCore DP TX device in question
+ * @enable: Flag to determine whether to enable (1) or disable (0) the enhanced
+ *	    frame mode
+ *
+ * Enable or disable the enhanced framing symbol sequence for
+ * both the DisplayPort TX core and the RX device.
+ *
+ * Return: 0 if enabling/disabling the enhanced frame mode was successful, -ve
+ *	   on error
+ */
+static int set_enhanced_frame_mode(struct udevice *dev, u8 enable)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u8 val;
+
+	if (!is_connected(dev))
+		return -ENODEV;
+
+	if (dp_tx->link_config.support_enhanced_framing_mode)
+		dp_tx->link_config.enhanced_framing_mode = enable;
+	else
+		dp_tx->link_config.enhanced_framing_mode = false;
+
+	/* Write enhanced frame mode enable to the DisplayPort TX core. */
+	set_reg(dev, REG_ENHANCED_FRAME_EN,
+		dp_tx->link_config.enhanced_framing_mode);
+
+	/* Write enhanced frame mode enable to the RX device. */
+	status = aux_read(dev, DPCD_LANE_COUNT_SET, 0x1, &val);
+	if (status)
+		return -EIO;
+
+	if (dp_tx->link_config.enhanced_framing_mode)
+		val |= DPCD_ENHANCED_FRAME_EN_MASK;
+	else
+		val &= ~DPCD_ENHANCED_FRAME_EN_MASK;
+
+	status = aux_write(dev, DPCD_LANE_COUNT_SET, 0x1, &val);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * set_lane_count() - Set the lane count
+ * @dev:        The LogiCore DP TX device in question
+ * @lane_count: Lane count to set
+ *
+ * Set the number of lanes to be used by the main link for both
+ * the DisplayPort TX core and the RX device.
+ *
+ * Return: 0 if setting the lane count was successful, -ve on error
+ */
+static int set_lane_count(struct udevice *dev, u8 lane_count)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u8 val;
+
+	if (!is_connected(dev))
+		return -ENODEV;
+
+	printf("       set lane count to %u\n", lane_count);
+
+	dp_tx->link_config.lane_count = lane_count;
+
+	/* Write the new lane count to the DisplayPort TX core. */
+	set_reg(dev, REG_LANE_COUNT_SET, dp_tx->link_config.lane_count);
+
+	/* Write the new lane count to the RX device. */
+	status = aux_read(dev, DPCD_LANE_COUNT_SET, 0x1, &val);
+	if (status)
+		return -EIO;
+	val &= ~DPCD_LANE_COUNT_SET_MASK;
+	val |= dp_tx->link_config.lane_count;
+
+	status = aux_write(dev, DPCD_LANE_COUNT_SET, 0x1, &val);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * set_clk_speed() - Set DP phy clock speed
+ * @dev:   The LogiCore DP TX device in question
+ * @speed: The clock frquency to set (one of PHY_CLOCK_SELECT_*)
+ *
+ * Set the clock frequency for the DisplayPort PHY corresponding to a desired
+ * data rate.
+ *
+ * Return: 0 if setting the DP phy clock speed was successful, -ve on error
+ */
+static int set_clk_speed(struct udevice *dev, u32 speed)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u32 val;
+	u32 mask;
+
+	/* Disable the DisplayPort TX core first. */
+	val = get_reg(dev, REG_ENABLE);
+	set_reg(dev, REG_ENABLE, 0x0);
+
+	/* Change speed of the feedback clock. */
+	set_reg(dev, REG_PHY_CLOCK_SELECT, speed);
+
+	/* Re-enable the DisplayPort TX core if it was previously enabled. */
+	if (val)
+		set_reg(dev, REG_ENABLE, 0x1);
+
+	/* Wait until the PHY is ready. */
+	mask = phy_status_lanes_ready_mask(dp_tx->max_lane_count);
+	status = wait_phy_ready(dev, mask);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * set_link_rate() - Set the link rate
+ * @dev:       The LogiCore DP TX device in question
+ * @link_rate: The link rate to set (one of LINK_BW_SET_*)
+ *
+ * Set the data rate to be used by the main link for both the DisplayPort TX
+ * core and the RX device.
+ *
+ * Return: 0 if setting the link rate was successful, -ve on error
+ */
+static int set_link_rate(struct udevice *dev, u8 link_rate)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+
+	/* Write a corresponding clock frequency to the DisplayPort TX core. */
+	switch (link_rate) {
+	case LINK_BW_SET_162GBPS:
+		printf("       set link rate to 1.62 Gb/s\n");
+		status = set_clk_speed(dev, PHY_CLOCK_SELECT_162GBPS);
+		break;
+	case LINK_BW_SET_270GBPS:
+		printf("       set link rate to 2.70 Gb/s\n");
+		status = set_clk_speed(dev, PHY_CLOCK_SELECT_270GBPS);
+		break;
+	case LINK_BW_SET_540GBPS:
+		printf("       set link rate to 5.40 Gb/s\n");
+		status = set_clk_speed(dev, PHY_CLOCK_SELECT_540GBPS);
+		break;
+	default:
+		return -EINVAL;
+	}
+	if (status)
+		return -EIO;
+
+	dp_tx->link_config.link_rate = link_rate;
+
+	/* Write new link rate to the DisplayPort TX core. */
+	set_reg(dev, REG_LINK_BW_SET, dp_tx->link_config.link_rate);
+
+	/* Write new link rate to the RX device. */
+	status = aux_write(dev, DPCD_LINK_BW_SET, 1,
+			   &dp_tx->link_config.link_rate);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/* Link training */
+
+/**
+ * get_training_delay() - Get training delay
+ * @dev:            The LogiCore DP TX device in question
+ * @training_state: The training state for which the required training delay
+ *		    should be queried
+ *
+ * Determine what the RX device's required training delay is for
+ * link training.
+ *
+ * Return: The training delay in us
+ */
+static int get_training_delay(struct udevice *dev, int training_state)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u16 delay;
+
+	switch (dp_tx->dpcd_rx_caps[DPCD_TRAIN_AUX_RD_INTERVAL]) {
+	case DPCD_TRAIN_AUX_RD_INT_100_400US:
+		if (training_state == TS_CLOCK_RECOVERY)
+			/* delay for the clock recovery phase. */
+			delay = 100;
+		else
+			/* delay for the channel equalization phase. */
+			delay = 400;
+		break;
+	case DPCD_TRAIN_AUX_RD_INT_4MS:
+		delay = 4000;
+		break;
+	case DPCD_TRAIN_AUX_RD_INT_8MS:
+		delay = 8000;
+		break;
+	case DPCD_TRAIN_AUX_RD_INT_12MS:
+		delay = 12000;
+		break;
+	case DPCD_TRAIN_AUX_RD_INT_16MS:
+		delay = 16000;
+		break;
+	default:
+		/* Default to 20 ms. */
+		delay = 20000;
+		break;
+	}
+
+	return delay;
+}
+
+/**
+ * set_vswing_preemp() - Build AUX data to set voltage swing and pre-emphasis
+ * @dev:      The LogiCore DP TX device in question
+ * @aux_data: Buffer to receive the built AUX data
+ *
+ * Build AUX data to set current voltage swing and pre-emphasis level settings;
+ * the necessary data is taken from the link_config structure.
+ */
+static void set_vswing_preemp(struct udevice *dev, u8 *aux_data)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u8 data;
+	u8 vs_level_rx = dp_tx->link_config.vs_level;
+	u8 pe_level_rx = dp_tx->link_config.pe_level;
+
+	/* Set up the data buffer for writing to the RX device. */
+	data = (pe_level_rx << DPCD_TRAINING_LANEX_SET_PE_SHIFT) | vs_level_rx;
+	/* The maximum voltage swing has been reached. */
+	if (vs_level_rx == MAXIMUM_VS_LEVEL)
+		data |= DPCD_TRAINING_LANEX_SET_MAX_VS_MASK;
+
+	/* The maximum pre-emphasis level has been reached. */
+	if (pe_level_rx == MAXIMUM_PE_LEVEL)
+		data |= DPCD_TRAINING_LANEX_SET_MAX_PE_MASK;
+	memset(aux_data, data, 4);
+}
+
+/**
+ * adj_vswing_preemp() - Adjust voltage swing and pre-emphasis
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Set new voltage swing and pre-emphasis levels using the
+ * adjustment requests obtained from the RX device.
+ *
+ * Return: 0 if voltage swing and pre-emphasis could be adjusted successfully,
+ *	   -ve on error
+ */
+static int adj_vswing_preemp(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u8 index;
+	u8 vs_level_adj_req[4];
+	u8 pe_level_adj_req[4];
+	u8 aux_data[4];
+	u8 *ajd_reqs = &dp_tx->lane_status_ajd_reqs[4];
+
+	/*
+	 * Analyze the adjustment requests for changes in voltage swing and
+	 * pre-emphasis levels.
+	 */
+	vs_level_adj_req[0] = ajd_reqs[0] & DPCD_ADJ_REQ_LANE_0_2_VS_MASK;
+	vs_level_adj_req[1] = (ajd_reqs[0] & DPCD_ADJ_REQ_LANE_1_3_VS_MASK) >>
+			      DPCD_ADJ_REQ_LANE_1_3_VS_SHIFT;
+	vs_level_adj_req[2] = ajd_reqs[1] & DPCD_ADJ_REQ_LANE_0_2_VS_MASK;
+	vs_level_adj_req[3] = (ajd_reqs[1] & DPCD_ADJ_REQ_LANE_1_3_VS_MASK) >>
+			      DPCD_ADJ_REQ_LANE_1_3_VS_SHIFT;
+	pe_level_adj_req[0] = (ajd_reqs[0] & DPCD_ADJ_REQ_LANE_0_2_PE_MASK) >>
+			      DPCD_ADJ_REQ_LANE_0_2_PE_SHIFT;
+	pe_level_adj_req[1] = (ajd_reqs[0] & DPCD_ADJ_REQ_LANE_1_3_PE_MASK) >>
+			      DPCD_ADJ_REQ_LANE_1_3_PE_SHIFT;
+	pe_level_adj_req[2] = (ajd_reqs[1] & DPCD_ADJ_REQ_LANE_0_2_PE_MASK) >>
+			      DPCD_ADJ_REQ_LANE_0_2_PE_SHIFT;
+	pe_level_adj_req[3] = (ajd_reqs[1] & DPCD_ADJ_REQ_LANE_1_3_PE_MASK) >>
+			      DPCD_ADJ_REQ_LANE_1_3_PE_SHIFT;
+
+	/*
+	 * Change the drive settings to match the adjustment requests. Use the
+	 * greatest level requested.
+	 */
+	dp_tx->link_config.vs_level = 0;
+	dp_tx->link_config.pe_level = 0;
+	for (index = 0; index < dp_tx->link_config.lane_count; index++) {
+		if (vs_level_adj_req[index] > dp_tx->link_config.vs_level)
+			dp_tx->link_config.vs_level = vs_level_adj_req[index];
+		if (pe_level_adj_req[index] > dp_tx->link_config.pe_level)
+			dp_tx->link_config.pe_level = pe_level_adj_req[index];
+	}
+
+	/*
+	 * Verify that the voltage swing and pre-emphasis combination is
+	 * allowed. Some combinations will result in a differential peak-to-peak
+	 * voltage that is outside the permissible range. See the VESA
+	 * DisplayPort v1.2 Specification, section 3.1.5.2.
+	 * The valid combinations are:
+	 *      PE=0    PE=1    PE=2    PE=3
+	 * VS=0 valid   valid   valid   valid
+	 * VS=1 valid   valid   valid
+	 * VS=2 valid   valid
+	 * VS=3 valid
+	 *
+	 * NOTE:
+	 * Xilinix dp_v3_1 driver seems to have an off by one error when
+	 * limiting pe_level which is fixed here.
+	 */
+	if (dp_tx->link_config.pe_level > (3 - dp_tx->link_config.vs_level))
+		dp_tx->link_config.pe_level = 3 - dp_tx->link_config.vs_level;
+
+	/*
+	 * Make the adjustments to both the DisplayPort TX core and the RX
+	 * device.
+	 */
+	set_vswing_preemp(dev, aux_data);
+	/*
+	 * Write the voltage swing and pre-emphasis levels for each lane to the
+	 * RX device.
+	 */
+	status = aux_write(dev, DPCD_TRAINING_LANE0_SET, 4, aux_data);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * get_lane_status_adj_reqs() - Read lane status and adjustment requests
+ *				information from the device
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Do a burst AUX read from the RX device over the AUX channel. The contents of
+ * the status registers will be stored for later use by check_clock_recovery,
+ * check_channel_equalization, and adj_vswing_preemp.
+ *
+ * Return: 0 if the status information were read successfully, -ve on error
+ */
+static int get_lane_status_adj_reqs(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+
+	/*
+	 * Read and store 4 bytes of lane status and 2 bytes of adjustment
+	 * requests.
+	 */
+	status = aux_read(dev, DPCD_STATUS_LANE_0_1, 6,
+			  dp_tx->lane_status_ajd_reqs);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * check_clock_recovery() - Check clock recovery success
+ * @dev:        The LogiCore DP TX device in question
+ * @lane_count: The number of lanes for which to check clock recovery success
+ *
+ * Check if the RX device's DisplayPort Configuration data (DPCD) indicates
+ * that the clock recovery sequence during link training was successful - the
+ * RX device's link clock and data recovery unit has realized and maintained
+ * the frequency lock for all lanes currently in use.
+ *
+ * Return: 0 if clock recovery was successful on all lanes in question, -ve if
+ *	   not
+ */
+static int check_clock_recovery(struct udevice *dev, u8 lane_count)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u8 *lane_status = dp_tx->lane_status_ajd_reqs;
+
+	/* Check that all LANEx_CR_DONE bits are set. */
+	switch (lane_count) {
+	case LANE_COUNT_SET_4:
+		if (!(lane_status[1] & DPCD_STATUS_LANE_3_CR_DONE_MASK))
+			goto out_fail;
+		if (!(lane_status[1] & DPCD_STATUS_LANE_2_CR_DONE_MASK))
+			goto out_fail;
+	/* Drop through and check lane 1. */
+	case LANE_COUNT_SET_2:
+		if (!(lane_status[0] & DPCD_STATUS_LANE_1_CR_DONE_MASK))
+			goto out_fail;
+	/* Drop through and check lane 0. */
+	case LANE_COUNT_SET_1:
+		if (!(lane_status[0] & DPCD_STATUS_LANE_0_CR_DONE_MASK))
+			goto out_fail;
+	default:
+		/* All (lane_count) lanes have achieved clock recovery. */
+		break;
+	}
+
+	return 0;
+
+out_fail:
+	return -EIO;
+}
+
+/**
+ * check_channel_equalization() - Check channel equalization success
+ * @dev:        The LogiCore DP TX device in question
+ * @lane_count: The number of lanes for which to check channel equalization
+ *		success
+ *
+ * Check if the RX device's DisplayPort Configuration data (DPCD) indicates
+ * that the channel equalization sequence during link training was successful -
+ * the RX device has achieved channel equalization, symbol lock, and interlane
+ * alignment for all lanes currently in use.
+ *
+ * Return: 0 if channel equalization was successful on all lanes in question,
+ *	   -ve if not
+ */
+static int check_channel_equalization(struct udevice *dev, u8 lane_count)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u8 *lane_status = dp_tx->lane_status_ajd_reqs;
+
+	/* Check that all LANEx_CHANNEL_EQ_DONE bits are set. */
+	switch (lane_count) {
+	case LANE_COUNT_SET_4:
+		if (!(lane_status[1] & DPCD_STATUS_LANE_3_CE_DONE_MASK))
+			goto out_fail;
+		if (!(lane_status[1] & DPCD_STATUS_LANE_2_CE_DONE_MASK))
+			goto out_fail;
+	/* Drop through and check lane 1. */
+	case LANE_COUNT_SET_2:
+		if (!(lane_status[0] & DPCD_STATUS_LANE_1_CE_DONE_MASK))
+			goto out_fail;
+	/* Drop through and check lane 0. */
+	case LANE_COUNT_SET_1:
+		if (!(lane_status[0] & DPCD_STATUS_LANE_0_CE_DONE_MASK))
+			goto out_fail;
+	default:
+		/* All (lane_count) lanes have achieved channel equalization. */
+		break;
+	}
+
+	/* Check that all LANEx_SYMBOL_LOCKED bits are set. */
+	switch (lane_count) {
+	case LANE_COUNT_SET_4:
+		if (!(lane_status[1] & DPCD_STATUS_LANE_3_SL_DONE_MASK))
+			goto out_fail;
+		if (!(lane_status[1] & DPCD_STATUS_LANE_2_SL_DONE_MASK))
+			goto out_fail;
+	/* Drop through and check lane 1. */
+	case LANE_COUNT_SET_2:
+		if (!(lane_status[0] & DPCD_STATUS_LANE_1_SL_DONE_MASK))
+			goto out_fail;
+	/* Drop through and check lane 0. */
+	case LANE_COUNT_SET_1:
+		if (!(lane_status[0] & DPCD_STATUS_LANE_0_SL_DONE_MASK))
+			goto out_fail;
+	default:
+		/* All (lane_count) lanes have achieved symbol lock. */
+		break;
+	}
+
+	/* Check that interlane alignment is done. */
+	if (!(lane_status[2] & DPCD_LANE_ALIGN_STATUS_UPDATED_IA_DONE_MASK))
+		goto out_fail;
+
+	return 0;
+
+out_fail:
+	return -EIO;
+}
+
+/**
+ * set_training_pattern() - Set training pattern for link training
+ * @dev:     The LogiCore DP TX device in question
+ * @pattern: The training pattern to set
+ *
+ * Set the training pattern to be used during link training for both the
+ * DisplayPort TX core and the RX device.
+ *
+ * Return: 0 if the training pattern could be set successfully, -ve if not
+ */
+static int set_training_pattern(struct udevice *dev, u32 pattern)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u8 aux_data[5];
+
+	/* Write to the DisplayPort TX core. */
+	set_reg(dev, REG_TRAINING_PATTERN_SET, pattern);
+
+	aux_data[0] = pattern;
+
+	/* Write scrambler disable to the DisplayPort TX core. */
+	switch (pattern) {
+	case TRAINING_PATTERN_SET_OFF:
+		set_reg(dev, REG_SCRAMBLING_DISABLE, 0);
+		dp_tx->link_config.scrambler_en = 1;
+		break;
+	case TRAINING_PATTERN_SET_TP1:
+	case TRAINING_PATTERN_SET_TP2:
+	case TRAINING_PATTERN_SET_TP3:
+		aux_data[0] |= DPCD_TP_SET_SCRAMB_DIS_MASK;
+		set_reg(dev, REG_SCRAMBLING_DISABLE, 1);
+		dp_tx->link_config.scrambler_en = 0;
+		break;
+	default:
+		break;
+	}
+
+	/*
+	 * Make the adjustments to both the DisplayPort TX core and the RX
+	 * device.
+	 */
+	set_vswing_preemp(dev, &aux_data[1]);
+	/*
+	 * Write the voltage swing and pre-emphasis levels for each lane to the
+	 * RX device.
+	 */
+	if  (pattern == TRAINING_PATTERN_SET_OFF)
+		status = aux_write(dev, DPCD_TP_SET, 1, aux_data);
+	else
+		status = aux_write(dev, DPCD_TP_SET, 5, aux_data);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/**
+ * training_state_clock_recovery() - Run clock recovery part of link training
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Run the clock recovery sequence as part of link training. The
+ * sequence is as follows:
+ *
+ *	0) Start signaling at the minimum voltage swing, pre-emphasis, and
+ *	   post- cursor levels.
+ *	1) Transmit training pattern 1 over the main link with symbol
+ *	   scrambling disabled.
+ *	2) The clock recovery loop. If clock recovery is unsuccessful after
+ *	   MaxIterations loop iterations, return.
+ *	2a) Wait for at least the period of time specified in the RX device's
+ *	    DisplayPort Configuration data (DPCD) register,
+ *	    TRAINING_AUX_RD_INTERVAL.
+ *	2b) Check if all lanes have achieved clock recovery lock. If so,
+ *	    return.
+ *	2c) Check if the same voltage swing level has been used 5 consecutive
+ *	    times or if the maximum level has been reached. If so, return.
+ *	2d) Adjust the voltage swing, pre-emphasis, and post-cursor levels as
+ *	    requested by the RX device.
+ *	2e) Loop back to 2a.
+ *
+ * For a more detailed description of the clock recovery sequence, see section
+ * 3.5.1.2.1 of the DisplayPort 1.2a specification document.
+ *
+ * Return: The next state machine state to advance to
+ */
+static unsigned int training_state_clock_recovery(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u32 delay_us;
+	u8 prev_vs_level = 0;
+	u8 same_vs_level_count = 0;
+
+	/*
+	 * Obtain the required delay for clock recovery as specified by the
+	 * RX device.
+	 */
+	delay_us = get_training_delay(dev, TS_CLOCK_RECOVERY);
+
+	/* Start CRLock. */
+
+	/* Transmit training pattern 1. */
+	/* Disable the scrambler. */
+	/* Start from minimal voltage swing and pre-emphasis levels. */
+	dp_tx->link_config.vs_level = 0;
+	dp_tx->link_config.pe_level = 0;
+	status = set_training_pattern(dev, TRAINING_PATTERN_SET_TP1);
+	if (status)
+		return TS_FAILURE;
+
+	while (1) {
+		/* Wait delay specified in TRAINING_AUX_RD_INTERVAL. */
+		udelay(delay_us);
+
+		/* Get lane and adjustment requests. */
+		status = get_lane_status_adj_reqs(dev);
+		if (status)
+			return TS_FAILURE;
+
+		/*
+		 * Check if all lanes have realized and maintained the frequency
+		 * lock and get adjustment requests.
+		 */
+		status = check_clock_recovery(dev,
+					      dp_tx->link_config.lane_count);
+		if (!status)
+			return TS_CHANNEL_EQUALIZATION;
+
+		/*
+		 * Check if the same voltage swing for each lane has been used 5
+		 * consecutive times.
+		 */
+		if (prev_vs_level == dp_tx->link_config.vs_level) {
+			same_vs_level_count++;
+		} else {
+			same_vs_level_count = 0;
+			prev_vs_level = dp_tx->link_config.vs_level;
+		}
+		if (same_vs_level_count >= 5)
+			break;
+
+		/* Only try maximum voltage swing once. */
+		if (dp_tx->link_config.vs_level == MAXIMUM_VS_LEVEL)
+			break;
+
+		/* Adjust the drive settings as requested by the RX device. */
+		status = adj_vswing_preemp(dev);
+		if (status)
+			/* The AUX write failed. */
+			return TS_FAILURE;
+	}
+
+	return TS_ADJUST_LINK_RATE;
+}
+
+/**
+ * training_state_channel_equalization() - Run channel equalization part of
+ *					   link training
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Run the channel equalization sequence as part of link
+ * training. The sequence is as follows:
+ *
+ *	0) Start signaling with the same drive settings used at the end of the
+ *	   clock recovery sequence.
+ *	1) Transmit training pattern 2 (or 3) over the main link with symbol
+ *	   scrambling disabled.
+ *	2) The channel equalization loop. If channel equalization is
+ *	   unsuccessful after 5 loop iterations, return.
+ *	2a) Wait for at least the period of time specified in the RX device's
+ *	    DisplayPort Configuration data (DPCD) register,
+ *	    TRAINING_AUX_RD_INTERVAL.
+ *	2b) Check if all lanes have achieved channel equalization, symbol lock,
+ *	    and interlane alignment. If so, return.
+ *	2c) Check if the same voltage swing level has been used 5 consecutive
+ *	    times or if the maximum level has been reached. If so, return.
+ *	2d) Adjust the voltage swing, pre-emphasis, and post-cursor levels as
+ *	    requested by the RX device.
+ *	2e) Loop back to 2a.
+ *
+ * For a more detailed description of the channel equalization sequence, see
+ * section 3.5.1.2.2 of the DisplayPort 1.2a specification document.
+ *
+ * Return: The next state machine state to advance to
+ */
+static int training_state_channel_equalization(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	u32 delay_us;
+	u32 iteration_count = 0;
+
+	/*
+	 * Obtain the required delay for channel equalization as specified by
+	 * the RX device.
+	 */
+	delay_us = get_training_delay(dev, TS_CHANNEL_EQUALIZATION);
+
+	/* Start channel equalization. */
+
+	/* Write the current drive settings. */
+	/* Transmit training pattern 2/3. */
+	if (dp_tx->dpcd_rx_caps[DPCD_MAX_LANE_COUNT] & DPCD_TPS3_SUPPORT_MASK)
+		status = set_training_pattern(dev, TRAINING_PATTERN_SET_TP3);
+	else
+		status = set_training_pattern(dev, TRAINING_PATTERN_SET_TP2);
+
+	if (status)
+		return TS_FAILURE;
+
+	while (iteration_count < 5) {
+		/* Wait delay specified in TRAINING_AUX_RD_INTERVAL. */
+		udelay(delay_us);
+
+		/* Get lane and adjustment requests. */
+		status = get_lane_status_adj_reqs(dev);
+		if (status)
+			/* The AUX read failed. */
+			return TS_FAILURE;
+
+		/* Check that all lanes still have their clocks locked. */
+		status = check_clock_recovery(dev,
+					      dp_tx->link_config.lane_count);
+		if (status)
+			break;
+
+		/*
+		 * Check if all lanes have accomplished channel equalization,
+		 * symbol lock, and interlane alignment.
+		 */
+		status =
+		    check_channel_equalization(dev,
+					       dp_tx->link_config.lane_count);
+		if (!status)
+			return TS_SUCCESS;
+
+		/* Adjust the drive settings as requested by the RX device. */
+		status = adj_vswing_preemp(dev);
+		if (status)
+			/* The AUX write failed. */
+			return TS_FAILURE;
+
+		iteration_count++;
+	}
+
+	/*
+	 * Tried 5 times with no success. Try a reduced bitrate first, then
+	 * reduce the number of lanes.
+	 */
+	return TS_ADJUST_LINK_RATE;
+}
+
+/**
+ * training_state_adjust_link_rate() - Downshift data rate and/or lane count
+ * @dev: The LogiCore DP TX device in question
+ *
+ * This function is reached if either the clock recovery or the channel
+ * equalization process failed during training. As a result, the data rate will
+ * be downshifted, and training will be re-attempted (starting with clock
+ * recovery) at the reduced data rate. If the data rate is already at 1.62
+ * Gbps, a downshift in lane count will be attempted.
+ *
+ * Return: The next state machine state to advance to
+ */
+static int training_state_adjust_link_rate(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+
+	switch (dp_tx->link_config.link_rate) {
+	case LINK_BW_SET_540GBPS:
+		status = set_link_rate(dev, LINK_BW_SET_270GBPS);
+		if (status) {
+			status = TS_FAILURE;
+			break;
+		}
+		status = TS_CLOCK_RECOVERY;
+		break;
+	case LINK_BW_SET_270GBPS:
+		status = set_link_rate(dev, LINK_BW_SET_162GBPS);
+		if (status) {
+			status = TS_FAILURE;
+			break;
+		}
+		status = TS_CLOCK_RECOVERY;
+		break;
+	default:
+		/*
+		 * Already at the lowest link rate. Try reducing the lane
+		 * count next.
+		 */
+		status = TS_ADJUST_LANE_COUNT;
+		break;
+	}
+
+	return status;
+}
+
+/**
+ * trainig_state_adjust_lane_count - Downshift lane count
+ * @dev: The LogiCore DP TX device in question
+ *
+ * This function is reached if either the clock recovery or the channel
+ * equalization process failed during training, and a minimal data rate of 1.62
+ * Gbps was being used. As a result, the number of lanes in use will be
+ * reduced, and training will be re-attempted (starting with clock recovery) at
+ * this lower lane count.
+ *
+ * Return: The next state machine state to advance to
+ */
+static int trainig_state_adjust_lane_count(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+
+	switch (dp_tx->link_config.lane_count) {
+	case LANE_COUNT_SET_4:
+		status = set_lane_count(dev, LANE_COUNT_SET_2);
+		if (status) {
+			status = TS_FAILURE;
+			break;
+		}
+
+		status = set_link_rate(dev, dp_tx->link_config.max_link_rate);
+		if (status) {
+			status = TS_FAILURE;
+			break;
+		}
+		status = TS_CLOCK_RECOVERY;
+		break;
+	case LANE_COUNT_SET_2:
+		status = set_lane_count(dev, LANE_COUNT_SET_1);
+		if (status) {
+			status = TS_FAILURE;
+			break;
+		}
+
+		status = set_link_rate(dev, dp_tx->link_config.max_link_rate);
+		if (status) {
+			status = TS_FAILURE;
+			break;
+		}
+		status = TS_CLOCK_RECOVERY;
+		break;
+	default:
+		/*
+		 * Already at the lowest lane count. Training has failed at the
+		 * lowest lane count and link rate.
+		 */
+		status = TS_FAILURE;
+		break;
+	}
+
+	return status;
+}
+
+/**
+ * check_link_status() - Check status of link
+ * @dev:        The LogiCore DP TX device in question
+ * @lane_count: The lane count to use for the check
+ *
+ * Check if the receiver's DisplayPort Configuration data (DPCD) indicates the
+ * receiver has achieved and maintained clock recovery, channel equalization,
+ * symbol lock, and interlane alignment for all lanes currently in use.
+ *
+ * Return: 0 if the link status is OK, -ve if a error occurred during checking
+ */
+static int check_link_status(struct udevice *dev, u8 lane_count)
+{
+	u8 retry_count = 0;
+
+	if (!is_connected(dev))
+		return -ENODEV;
+
+	/* Retrieve AUX info. */
+	do {
+		int status;
+
+		/* Get lane and adjustment requests. */
+		status = get_lane_status_adj_reqs(dev);
+		if (status)
+			return -EIO;
+
+		/* Check if the link needs training. */
+		if ((check_clock_recovery(dev, lane_count) == 0) &&
+		    (check_channel_equalization(dev, lane_count) == 0))
+			return 0;
+
+		retry_count++;
+	} while (retry_count < 5); /* Retry up to 5 times. */
+
+	return -EIO;
+}
+
+/**
+ * run_training() - Run link training
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Run the link training process. It is implemented as a state machine, with
+ * each state returning the next state. First, the clock recovery sequence will
+ * be run; if successful, the channel equalization sequence will run. If either
+ * the clock recovery or channel equalization sequence failed, the link rate or
+ * the number of lanes used will be reduced and training will be re-attempted.
+ * If training fails at the minimal data rate, 1.62 Gbps with a single lane,
+ * training will no longer re-attempt and fail.
+ *
+ * ### Here be dragons ###
+ * There are undocumented timeout constraints in the link training process. In
+ * DP v1.2a spec, Chapter 3.5.1.2.2 a 10ms limit for the complete training
+ * process is mentioned. Which individual timeouts are derived and implemented
+ * by sink manufacturers is unknown. So each step should be as short as
+ * possible and link training should start as soon as possible after HPD.
+ *
+ * Return: 0 if the training sequence ran successfully, -ve if a error occurred
+ *	   or the training failed
+ */
+static int run_training(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	int training_state = TS_CLOCK_RECOVERY;
+
+	while (1) {
+		switch (training_state) {
+		case TS_CLOCK_RECOVERY:
+			training_state =
+				training_state_clock_recovery(dev);
+			break;
+		case TS_CHANNEL_EQUALIZATION:
+			training_state =
+				training_state_channel_equalization(dev);
+			break;
+		case TS_ADJUST_LINK_RATE:
+			training_state =
+				training_state_adjust_link_rate(dev);
+			break;
+		case TS_ADJUST_LANE_COUNT:
+			training_state =
+				trainig_state_adjust_lane_count(dev);
+			break;
+		default:
+			break;
+		}
+
+		if (training_state == TS_SUCCESS)
+			break;
+		else if (training_state == TS_FAILURE)
+			return -EIO;
+
+		if (training_state == TS_ADJUST_LINK_RATE ||
+		    training_state == TS_ADJUST_LANE_COUNT) {
+			if (!dp_tx->train_adaptive)
+				return -EIO;
+
+			status = set_training_pattern(dev,
+						      TRAINING_PATTERN_SET_OFF);
+			if (status)
+				return -EIO;
+		}
+	}
+
+	/* Final status check. */
+	status = check_link_status(dev, dp_tx->link_config.lane_count);
+	if (status)
+		return -EIO;
+
+	return 0;
+}
+
+/* Link policy maker */
+
+/**
+ * cfg_main_link_max() - Determine best common capabilities
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Determine the common capabilities between the DisplayPort TX core and the RX
+ * device.
+ *
+ * Return: 0 if the determination succeeded, -ve on error
+ */
+static int cfg_main_link_max(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+
+	if (!is_connected(dev))
+		return -ENODEV;
+
+	/*
+	 * Configure the main link to the maximum common link rate between the
+	 * DisplayPort TX core and the RX device.
+	 */
+	status = set_link_rate(dev, dp_tx->link_config.max_link_rate);
+	if (status)
+		return status;
+
+	/*
+	 * Configure the main link to the maximum common lane count between the
+	 * DisplayPort TX core and the RX device.
+	 */
+	status = set_lane_count(dev, dp_tx->link_config.max_lane_count);
+	if (status)
+		return status;
+
+	return 0;
+}
+
+/**
+ * establish_link() - Establish a link
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Check if the link needs training and run the training sequence if training
+ * is required.
+ *
+ * Return: 0 if the link was established successfully, -ve on error
+ */
+static int establish_link(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int status;
+	int status2;
+	u32 mask;
+
+	reset_dp_phy(dev, PHY_CONFIG_PHY_RESET_MASK);
+
+	/* Disable main link during training. */
+	disable_main_link(dev);
+
+	/* Wait for the PHY to be ready. */
+	mask = phy_status_lanes_ready_mask(dp_tx->max_lane_count);
+	status = wait_phy_ready(dev, mask);
+	if (status)
+		return -EIO;
+
+	/* Train main link. */
+	status = run_training(dev);
+
+	/* Turn off the training pattern and enable scrambler. */
+	status2 = set_training_pattern(dev, TRAINING_PATTERN_SET_OFF);
+	if (status || status2)
+		return -EIO;
+
+	return 0;
+}
+
+/*
+ * Stream policy maker
+ */
+
+/**
+ * cfg_msa_recalculate() - Calculate MSA parameters
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Calculate the following Main Stream Attributes (MSA):
+ * - Transfer unit size
+ * - User pixel width
+ * - Horizontal total clock
+ * - Vertical total clock
+ * - misc_0
+ * - misc_1
+ * - Data per lane
+ * - Average number of bytes per transfer unit
+ * - Number of initial wait cycles
+ *
+ * These values are derived from:
+ * - Bits per color
+ * - Horizontal resolution
+ * - Vertical resolution
+ * - Horizontal blank start
+ * - Vertical blank start
+ * - Pixel clock (in KHz)
+ * - Horizontal sync polarity
+ * - Vertical sync polarity
+ * - Horizontal sync pulse width
+ * - Vertical sync pulse width
+ */
+static void cfg_msa_recalculate(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u32 video_bw;
+	u32 link_bw;
+	u32 words_per_line;
+	u8 bits_per_pixel;
+	struct main_stream_attributes *msa_config;
+	struct link_config *link_config;
+
+	msa_config = &dp_tx->main_stream_attributes;
+	link_config = &dp_tx->link_config;
+
+	/*
+	 * Set the user pixel width to handle clocks that exceed the
+	 * capabilities of the DisplayPort TX core.
+	 */
+	if (msa_config->override_user_pixel_width == 0) {
+		if (msa_config->pixel_clock_hz > 300000000 &&
+		    link_config->lane_count == LANE_COUNT_SET_4) {
+			msa_config->user_pixel_width = 4;
+		} /*
+		   * Xilinx driver used 75 MHz as a limit here, 150 MHZ should
+		   * be more sane
+		   */
+		else if ((msa_config->pixel_clock_hz > 150000000) &&
+			 (link_config->lane_count != LANE_COUNT_SET_1)) {
+			msa_config->user_pixel_width = 2;
+		} else {
+			msa_config->user_pixel_width = 1;
+		}
+	}
+
+	/* Compute the rest of the MSA values. */
+	msa_config->n_vid = 27 * 1000 * link_config->link_rate;
+
+	/* Miscellaneous attributes. */
+	if (msa_config->bits_per_color == 6)
+		msa_config->misc_0 = MAIN_STREAMX_MISC0_BDC_6BPC;
+	else if (msa_config->bits_per_color == 8)
+		msa_config->misc_0 = MAIN_STREAMX_MISC0_BDC_8BPC;
+	else if (msa_config->bits_per_color == 10)
+		msa_config->misc_0 = MAIN_STREAMX_MISC0_BDC_10BPC;
+	else if (msa_config->bits_per_color == 12)
+		msa_config->misc_0 = MAIN_STREAMX_MISC0_BDC_12BPC;
+	else if (msa_config->bits_per_color == 16)
+		msa_config->misc_0 = MAIN_STREAMX_MISC0_BDC_16BPC;
+
+	msa_config->misc_0 = (msa_config->misc_0 <<
+			      MAIN_STREAMX_MISC0_BDC_SHIFT) |
+			     (msa_config->y_cb_cr_colorimetry <<
+			      MAIN_STREAMX_MISC0_YCBCR_COLORIMETRY_SHIFT) |
+			     (msa_config->dynamic_range <<
+			      MAIN_STREAMX_MISC0_DYNAMIC_RANGE_SHIFT) |
+			     (msa_config->component_format <<
+			      MAIN_STREAMX_MISC0_COMPONENT_FORMAT_SHIFT) |
+			     (msa_config->synchronous_clock_mode);
+
+	msa_config->misc_1 = 0;
+
+	/*
+	 * Determine the number of bits per pixel for the specified color
+	 * component format.
+	 */
+	if (msa_config->component_format ==
+	    MAIN_STREAMX_MISC0_COMPONENT_FORMAT_YCBCR422)
+		/* YCbCr422 color component format. */
+		bits_per_pixel = msa_config->bits_per_color * 2;
+	else
+		/* RGB or YCbCr 4:4:4 color component format. */
+		bits_per_pixel = msa_config->bits_per_color * 3;
+
+	/* Calculate the data per lane. */
+	words_per_line = (msa_config->h_active * bits_per_pixel);
+	if (words_per_line % 16)
+		words_per_line += 16;
+	words_per_line /= 16;
+
+	msa_config->data_per_lane = words_per_line - link_config->lane_count;
+	if (words_per_line % link_config->lane_count)
+		msa_config->data_per_lane += (words_per_line %
+					      link_config->lane_count);
+
+	/*
+	 * Allocate a fixed size for single-stream transport (SST)
+	 * operation.
+	 */
+	msa_config->transfer_unit_size = 64;
+
+	/*
+	 * Calculate the average number of bytes per transfer unit.
+	 * Note: Both the integer and the fractional part is stored in
+	 * avg_bytes_per_tu.
+	 */
+	video_bw = ((msa_config->pixel_clock_hz / 1000) * bits_per_pixel) / 8;
+	link_bw = (link_config->lane_count * link_config->link_rate * 27);
+	msa_config->avg_bytes_per_tu = (video_bw *
+					msa_config->transfer_unit_size) /
+					link_bw;
+
+	/*
+	 * The number of initial wait cycles at the start of a new line
+	 * by the framing logic. This allows enough data to be buffered
+	 * in the input FIFO before video is sent.
+	 */
+	if ((msa_config->avg_bytes_per_tu / 1000) <= 4)
+		msa_config->init_wait = 64;
+	else
+		msa_config->init_wait = msa_config->transfer_unit_size -
+					(msa_config->avg_bytes_per_tu / 1000);
+}
+
+/**
+ * set_line_reset() - Enable/Disable end-of-line-reset
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Disable/enable the end-of-line-reset to the internal video pipe in case of
+ * reduced blanking as required.
+ */
+static void set_line_reset(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	u32 reg_val;
+	u16 h_blank;
+	u16 h_reduced_blank;
+	struct main_stream_attributes *msa_config =
+		&dp_tx->main_stream_attributes;
+
+	h_blank = msa_config->h_total - msa_config->h_active;
+	/* Reduced blanking starts at ceil(0.2 * HTotal). */
+	h_reduced_blank = 2 * msa_config->h_total;
+	if (h_reduced_blank % 10)
+		h_reduced_blank += 10;
+	h_reduced_blank /= 10;
+
+	/* CVT spec. states h_blank is either 80 or 160 for reduced blanking. */
+	reg_val = get_reg(dev, REG_LINE_RESET_DISABLE);
+	if (h_blank < h_reduced_blank &&
+	    (h_blank == 80 || h_blank == 160)) {
+		reg_val |= LINE_RESET_DISABLE_MASK;
+	} else {
+		reg_val &= ~LINE_RESET_DISABLE_MASK;
+	}
+	set_reg(dev, REG_LINE_RESET_DISABLE, reg_val);
+}
+
+/**
+ * clear_msa_values() - Clear MSA values
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Clear the main stream attributes registers of the DisplayPort TX core.
+ */
+static void clear_msa_values(struct udevice *dev)
+{
+	set_reg(dev, REG_MAIN_STREAM_HTOTAL, 0);
+	set_reg(dev, REG_MAIN_STREAM_VTOTAL, 0);
+	set_reg(dev, REG_MAIN_STREAM_POLARITY, 0);
+	set_reg(dev, REG_MAIN_STREAM_HSWIDTH, 0);
+	set_reg(dev, REG_MAIN_STREAM_VSWIDTH, 0);
+	set_reg(dev, REG_MAIN_STREAM_HRES, 0);
+	set_reg(dev, REG_MAIN_STREAM_VRES, 0);
+	set_reg(dev, REG_MAIN_STREAM_HSTART, 0);
+	set_reg(dev, REG_MAIN_STREAM_VSTART, 0);
+	set_reg(dev, REG_MAIN_STREAM_MISC0, 0);
+	set_reg(dev, REG_MAIN_STREAM_MISC1, 0);
+	set_reg(dev, REG_USER_PIXEL_WIDTH, 0);
+	set_reg(dev, REG_USER_DATA_COUNT_PER_LANE, 0);
+	set_reg(dev, REG_M_VID, 0);
+	set_reg(dev, REG_N_VID, 0);
+
+	set_reg(dev, REG_STREAM1, 0);
+	set_reg(dev, REG_TU_SIZE, 0);
+	set_reg(dev, REG_MIN_BYTES_PER_TU, 0);
+	set_reg(dev, REG_FRAC_BYTES_PER_TU, 0);
+	set_reg(dev, REG_INIT_WAIT, 0);
+}
+
+/**
+ * set_msa_values() - Set MSA values
+ * @dev: The LogiCore DP TX device in question
+ *
+ * Set the main stream attributes registers of the DisplayPort TX
+ * core with the values specified in the main stream attributes configuration
+ * structure.
+ */
+static void set_msa_values(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	struct main_stream_attributes *msa_config =
+		&dp_tx->main_stream_attributes;
+
+	printf("       set MSA %u x %u\n", msa_config->h_active,
+	       msa_config->v_active);
+
+	set_reg(dev, REG_MAIN_STREAM_HTOTAL, msa_config->h_total);
+	set_reg(dev, REG_MAIN_STREAM_VTOTAL, msa_config->v_total);
+	set_reg(dev, REG_MAIN_STREAM_POLARITY,
+		msa_config->h_sync_polarity |
+		(msa_config->v_sync_polarity <<
+		 MAIN_STREAMX_POLARITY_VSYNC_POL_SHIFT));
+	set_reg(dev, REG_MAIN_STREAM_HSWIDTH, msa_config->h_sync_width);
+	set_reg(dev, REG_MAIN_STREAM_VSWIDTH, msa_config->v_sync_width);
+	set_reg(dev, REG_MAIN_STREAM_HRES, msa_config->h_active);
+	set_reg(dev, REG_MAIN_STREAM_VRES, msa_config->v_active);
+	set_reg(dev, REG_MAIN_STREAM_HSTART, msa_config->h_start);
+	set_reg(dev, REG_MAIN_STREAM_VSTART, msa_config->v_start);
+	set_reg(dev, REG_MAIN_STREAM_MISC0, msa_config->misc_0);
+	set_reg(dev, REG_MAIN_STREAM_MISC1, msa_config->misc_1);
+	set_reg(dev, REG_USER_PIXEL_WIDTH, msa_config->user_pixel_width);
+
+	set_reg(dev, REG_M_VID, msa_config->pixel_clock_hz / 1000);
+	set_reg(dev, REG_N_VID, msa_config->n_vid);
+	set_reg(dev, REG_USER_DATA_COUNT_PER_LANE, msa_config->data_per_lane);
+
+	set_line_reset(dev);
+
+	set_reg(dev, REG_TU_SIZE, msa_config->transfer_unit_size);
+	set_reg(dev, REG_MIN_BYTES_PER_TU, msa_config->avg_bytes_per_tu / 1000);
+	set_reg(dev, REG_FRAC_BYTES_PER_TU,
+		(msa_config->avg_bytes_per_tu % 1000) * 1024 / 1000);
+	set_reg(dev, REG_INIT_WAIT, msa_config->init_wait);
+}
+
+/*
+ * external API
+ */
+
+/**
+ * logicore_dp_tx_set_msa() - Set given MSA values on device
+ * @dev: The LogiCore DP TX device in question
+ * @msa: The MSA values to set for the device
+ */
+static void logicore_dp_tx_set_msa(struct udevice *dev,
+				   struct logicore_dp_tx_msa *msa)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+
+	memset(&dp_tx->main_stream_attributes, 0,
+	       sizeof(struct main_stream_attributes));
+
+	dp_tx->main_stream_attributes.pixel_clock_hz = msa->pixel_clock_hz;
+	dp_tx->main_stream_attributes.bits_per_color = msa->bits_per_color;
+	dp_tx->main_stream_attributes.h_active = msa->h_active;
+	dp_tx->main_stream_attributes.h_start = msa->h_start;
+	dp_tx->main_stream_attributes.h_sync_polarity = msa->h_sync_polarity;
+	dp_tx->main_stream_attributes.h_sync_width = msa->h_sync_width;
+	dp_tx->main_stream_attributes.h_total = msa->h_total;
+	dp_tx->main_stream_attributes.v_active = msa->v_active;
+	dp_tx->main_stream_attributes.v_start = msa->v_start;
+	dp_tx->main_stream_attributes.v_sync_polarity = msa->v_sync_polarity;
+	dp_tx->main_stream_attributes.v_sync_width = msa->v_sync_width;
+	dp_tx->main_stream_attributes.v_total = msa->v_total;
+	dp_tx->main_stream_attributes.override_user_pixel_width =
+		msa->override_user_pixel_width;
+	dp_tx->main_stream_attributes.user_pixel_width = msa->user_pixel_width;
+	dp_tx->main_stream_attributes.synchronous_clock_mode = 0;
+}
+
+/**
+ * logicore_dp_tx_video_enable() - Enable video output
+ * @dev: The LogiCore DP TX device in question
+ * @msa: The MSA values to set for the device
+ *
+ * Return: 0 if the video was enabled successfully, -ve on error
+ */
+static int logicore_dp_tx_video_enable(struct udevice *dev,
+				       struct logicore_dp_tx_msa *msa)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+	int res;
+	u8 power = 0x01;
+
+	if (!is_connected(dev)) {
+		printf("       no DP sink connected\n");
+		return -EIO;
+	}
+
+	initialize(dev);
+
+	disable_main_link(dev);
+
+	logicore_dp_tx_set_msa(dev, msa);
+
+	get_rx_capabilities(dev);
+
+	printf("       DP sink connected\n");
+	aux_write(dev, DPCD_SET_POWER_DP_PWR_VOLTAGE, 1, &power);
+	set_enhanced_frame_mode(dev, true);
+	cfg_main_link_max(dev);
+	res = establish_link(dev);
+	printf("       establish_link: %s, vs: %d, pe: %d\n",
+	       res ? "failed" : "ok", dp_tx->link_config.vs_level,
+	       dp_tx->link_config.pe_level);
+
+	cfg_msa_recalculate(dev);
+
+	clear_msa_values(dev);
+	set_msa_values(dev);
+
+	enable_main_link(dev);
+
+	return 0;
+}
+
+/*
+ * Driver functions
+ */
+
+static int logicore_dp_tx_enable(struct udevice *dev, int panel_bpp,
+				 const struct display_timing *timing)
+{
+	struct clk pixclock;
+	struct logicore_dp_tx_msa *msa;
+	struct logicore_dp_tx_msa mode_640_480_60 = {
+		.pixel_clock_hz = 25175000,
+		.bits_per_color = 8,
+		.h_active = 640,
+		.h_start = 144,
+		.h_sync_polarity = false,
+		.h_sync_width = 96,
+		.h_total = 800,
+		.v_active = 480,
+		.v_start = 35,
+		.v_sync_polarity = false,
+		.v_sync_width = 2,
+		.v_total = 525,
+		.override_user_pixel_width = false,
+		.user_pixel_width = 0,
+	};
+
+	struct logicore_dp_tx_msa mode_720_400_70 = {
+		.pixel_clock_hz = 28300000,
+		.bits_per_color = 8,
+		.h_active = 720,
+		.h_start = 162,
+		.h_sync_polarity = false,
+		.h_sync_width = 108,
+		.h_total = 900,
+		.v_active = 400,
+		.v_start = 37,
+		.v_sync_polarity = true,
+		.v_sync_width = 2,
+		.v_total = 449,
+		.override_user_pixel_width = false,
+		.user_pixel_width = 0,
+	};
+
+	struct logicore_dp_tx_msa mode_1024_768_60 = {
+		.pixel_clock_hz = 65000000,
+		.bits_per_color = 8,
+		.h_active = 1024,
+		.h_start = 296,
+		.h_sync_polarity = false,
+		.h_sync_width = 136,
+		.h_total = 1344,
+		.v_active = 768,
+		.v_start = 35,
+		.v_sync_polarity = false,
+		.v_sync_width = 2,
+		.v_total = 806,
+		.override_user_pixel_width = false,
+		.user_pixel_width = 0,
+	};
+
+	if (timing->hactive.typ == 1024 && timing->vactive.typ == 768)
+		msa = &mode_1024_768_60;
+	else if (timing->hactive.typ == 720 && timing->vactive.typ == 400)
+		msa = &mode_720_400_70;
+	else
+		msa = &mode_640_480_60;
+
+	if (clk_get_by_index(dev, 0, &pixclock)) {
+		printf("%s: Could not get pixelclock\n", dev->name);
+		return -1;
+	}
+	clk_set_rate(&pixclock, msa->pixel_clock_hz);
+
+	return logicore_dp_tx_video_enable(dev, msa);
+}
+
+static int logicore_dp_tx_probe(struct udevice *dev)
+{
+	struct dp_tx *dp_tx = dev_get_priv(dev);
+
+	dp_tx->s_axi_clk = S_AXI_CLK_DEFAULT;
+	dp_tx->train_adaptive = false;
+	dp_tx->max_link_rate = DPCD_MAX_LINK_RATE_540GBPS;
+	dp_tx->max_lane_count = DPCD_MAX_LANE_COUNT_4;
+
+	dp_tx->base = dev_read_u32_default(dev, "reg", -1);
+
+	return 0;
+}
+
+static const struct dm_display_ops logicore_dp_tx_ops = {
+	.enable = logicore_dp_tx_enable,
+};
+
+static const struct udevice_id logicore_dp_tx_ids[] = {
+	{ .compatible = "gdsys,logicore_dp_tx" },
+	{ /* sentinel */ }
+};
+
+U_BOOT_DRIVER(logicore_dp_tx) = {
+	.name			= "logicore_dp_tx",
+	.id			= UCLASS_DISPLAY,
+	.of_match		= logicore_dp_tx_ids,
+	.probe			= logicore_dp_tx_probe,
+	.priv_auto_alloc_size	= sizeof(struct dp_tx),
+	.ops			= &logicore_dp_tx_ops,
+};