/*
 * Xilinx DRM DisplayPort encoder driver for Xilinx
 *
 *  Copyright (C) 2014 Xilinx, Inc.
 *
 *  Author: Hyun Woo Kwon <hyunk@xilinx.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_dp_helper.h>
#include <drm/drm_encoder_slave.h>

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/phy/phy.h>
#include <linux/phy/phy-zynqmp.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>

#include "xilinx_drm_dp_sub.h"
#include "xilinx_drm_drv.h"

static uint xilinx_drm_dp_aux_timeout_ms = 50;
module_param_named(aux_timeout_ms, xilinx_drm_dp_aux_timeout_ms, uint, 0444);
MODULE_PARM_DESC(aux_timeout_ms,
                 "DP aux timeout value in msec (default: 50)");

/* Link configuration registers */
#define XILINX_DP_TX_LINK_BW_SET                        0x0
#define XILINX_DP_TX_LANE_CNT_SET                       0x4
#define XILINX_DP_TX_ENHANCED_FRAME_EN                  0x8
#define XILINX_DP_TX_TRAINING_PATTERN_SET               0xc
#define XILINX_DP_TX_SCRAMBLING_DISABLE                 0x14
#define XILINX_DP_TX_DOWNSPREAD_CTL                     0x18
#define XILINX_DP_TX_SW_RESET                           0x1c
#define XILINX_DP_TX_SW_RESET_STREAM1                   (1 << 0)
#define XILINX_DP_TX_SW_RESET_STREAM2                   (1 << 1)
#define XILINX_DP_TX_SW_RESET_STREAM3                   (1 << 2)
#define XILINX_DP_TX_SW_RESET_STREAM4                   (1 << 3)
#define XILINX_DP_TX_SW_RESET_AUX                       (1 << 7)
#define XILINX_DP_TX_SW_RESET_ALL                       (XILINX_DP_TX_SW_RESET_STREAM1 | \
                                                         XILINX_DP_TX_SW_RESET_STREAM2 | \
                                                         XILINX_DP_TX_SW_RESET_STREAM3 | \
                                                         XILINX_DP_TX_SW_RESET_STREAM4 | \
                                                         XILINX_DP_TX_SW_RESET_AUX)

/* Core enable registers */
#define XILINX_DP_TX_ENABLE                             0x80
#define XILINX_DP_TX_ENABLE_MAIN_STREAM                 0x84
#define XILINX_DP_TX_FORCE_SCRAMBLER_RESET              0xc0
#define XILINX_DP_TX_VERSION                            0xf8
#define XILINX_DP_TX_VERSION_MAJOR_MASK                 (0xff << 24)
#define XILINX_DP_TX_VERSION_MAJOR_SHIFT                24
#define XILINX_DP_TX_VERSION_MINOR_MASK                 (0xff << 16)
#define XILINX_DP_TX_VERSION_MINOR_SHIFT                16
#define XILINX_DP_TX_VERSION_REVISION_MASK              (0xf << 12)
#define XILINX_DP_TX_VERSION_REVISION_SHIFT             12
#define XILINX_DP_TX_VERSION_PATCH_MASK                 (0xf << 8)
#define XILINX_DP_TX_VERSION_PATCH_SHIFT                8
#define XILINX_DP_TX_VERSION_INTERNAL_MASK              (0xff << 0)
#define XILINX_DP_TX_VERSION_INTERNAL_SHIFT             0

/* Core ID registers */
#define XILINX_DP_TX_CORE_ID                            0xfc
#define XILINX_DP_TX_CORE_ID_MAJOR_MASK                 (0xff << 24)
#define XILINX_DP_TX_CORE_ID_MAJOR_SHIFT                24
#define XILINX_DP_TX_CORE_ID_MINOR_MASK                 (0xff << 16)
#define XILINX_DP_TX_CORE_ID_MINOR_SHIFT                16
#define XILINX_DP_TX_CORE_ID_REVISION_MASK              (0xff << 8)
#define XILINX_DP_TX_CORE_ID_REVISION_SHIFT             8
#define XILINX_DP_TX_CORE_ID_DIRECTION                  (1 << 0)

/* AUX channel interface registers */
#define XILINX_DP_TX_AUX_COMMAND                        0x100
#define XILINX_DP_TX_AUX_COMMAND_CMD_SHIFT              8
#define XILINX_DP_TX_AUX_COMMAND_ADDRESS_ONLY           BIT(12)
#define XILINX_DP_TX_AUX_COMMAND_BYTES_SHIFT            0
#define XILINX_DP_TX_AUX_WRITE_FIFO                     0x104
#define XILINX_DP_TX_AUX_ADDRESS                        0x108
#define XILINX_DP_TX_CLK_DIVIDER                        0x10c
#define XILINX_DP_TX_CLK_DIVIDER_MHZ                    1000000
#define XILINX_DP_TX_CLK_DIVIDER_AUX_FILTER_SHIFT       8
#define XILINX_DP_TX_INTR_SIGNAL_STATE                  0x130
#define XILINX_DP_TX_INTR_SIGNAL_STATE_HPD              (1 << 0)
#define XILINX_DP_TX_INTR_SIGNAL_STATE_REQUEST          (1 << 1)
#define XILINX_DP_TX_INTR_SIGNAL_STATE_REPLY            (1 << 2)
#define XILINX_DP_TX_INTR_SIGNAL_STATE_REPLY_TIMEOUT    (1 << 3)
#define XILINX_DP_TX_AUX_REPLY_DATA                     0x134
#define XILINX_DP_TX_AUX_REPLY_CODE                     0x138
#define XILINX_DP_TX_AUX_REPLY_CODE_AUX_ACK             (0)
#define XILINX_DP_TX_AUX_REPLY_CODE_AUX_NACK            (1 << 0)
#define XILINX_DP_TX_AUX_REPLY_CODE_AUX_DEFER           (1 << 1)
#define XILINX_DP_TX_AUX_REPLY_CODE_I2C_ACK             (0)
#define XILINX_DP_TX_AUX_REPLY_CODE_I2C_NACK            (1 << 2)
#define XILINX_DP_TX_AUX_REPLY_CODE_I2C_DEFER           (1 << 3)
#define XILINX_DP_TX_AUX_REPLY_CNT                      0x13c
#define XILINX_DP_TX_AUX_REPLY_CNT_MASK                 0xff
#define XILINX_DP_TX_INTR_STATUS                        0x140
#define XILINX_DP_TX_INTR_MASK                          0x144
#define XILINX_DP_TX_INTR_HPD_IRQ                       (1 << 0)
#define XILINX_DP_TX_INTR_HPD_EVENT                     (1 << 1)
#define XILINX_DP_TX_INTR_REPLY_RECV                    (1 << 2)
#define XILINX_DP_TX_INTR_REPLY_TIMEOUT                 (1 << 3)
#define XILINX_DP_TX_INTR_HPD_PULSE                     (1 << 4)
#define XILINX_DP_TX_INTR_EXT_PKT_TXD                   (1 << 5)
#define XILINX_DP_TX_INTR_LIV_ABUF_UNDRFLW              (1 << 12)
#define XILINX_DP_TX_INTR_VBLANK_START                  (1 << 13)
#define XILINX_DP_TX_INTR_PIXEL0_MATCH                  (1 << 14)
#define XILINX_DP_TX_INTR_PIXEL1_MATCH                  (1 << 15)
#define XILINX_DP_TX_INTR_CHBUF_UNDERFLW_MASK           0x3f0000
#define XILINX_DP_TX_INTR_CHBUF_OVERFLW_MASK            0xfc00000
#define XILINX_DP_TX_INTR_CUST_TS_2                     (1 << 28)
#define XILINX_DP_TX_INTR_CUST_TS                       (1 << 29)
#define XILINX_DP_TX_INTR_EXT_VSYNC_TS                  (1 << 30)
#define XILINX_DP_TX_INTR_VSYNC_TS                      (1 << 31)
#define XILINX_DP_TX_INTR_ALL                           (XILINX_DP_TX_INTR_HPD_IRQ | \
                                                         XILINX_DP_TX_INTR_HPD_EVENT | \
                                                         XILINX_DP_TX_INTR_REPLY_RECV | \
                                                         XILINX_DP_TX_INTR_REPLY_TIMEOUT | \
                                                         XILINX_DP_TX_INTR_HPD_PULSE | \
                                                         XILINX_DP_TX_INTR_EXT_PKT_TXD | \
                                                         XILINX_DP_TX_INTR_LIV_ABUF_UNDRFLW | \
                                                         XILINX_DP_TX_INTR_VBLANK_START | \
                                                         XILINX_DP_TX_INTR_CHBUF_UNDERFLW_MASK | \
                                                         XILINX_DP_TX_INTR_CHBUF_OVERFLW_MASK)
#define XILINX_DP_TX_REPLY_DATA_CNT                     0x148
#define XILINX_DP_SUB_TX_INTR_STATUS                    0x3a0
#define XILINX_DP_SUB_TX_INTR_MASK                      0x3a4
#define XILINX_DP_SUB_TX_INTR_EN                        0x3a8
#define XILINX_DP_SUB_TX_INTR_DS                        0x3ac

/* Main stream attribute registers */
#define XILINX_DP_TX_MAIN_STREAM_HTOTAL                 0x180
#define XILINX_DP_TX_MAIN_STREAM_VTOTAL                 0x184
#define XILINX_DP_TX_MAIN_STREAM_POLARITY               0x188
#define XILINX_DP_TX_MAIN_STREAM_POLARITY_HSYNC_SHIFT   0
#define XILINX_DP_TX_MAIN_STREAM_POLARITY_VSYNC_SHIFT   1
#define XILINX_DP_TX_MAIN_STREAM_HSWIDTH                0x18c
#define XILINX_DP_TX_MAIN_STREAM_VSWIDTH                0x190
#define XILINX_DP_TX_MAIN_STREAM_HRES                   0x194
#define XILINX_DP_TX_MAIN_STREAM_VRES                   0x198
#define XILINX_DP_TX_MAIN_STREAM_HSTART                 0x19c
#define XILINX_DP_TX_MAIN_STREAM_VSTART                 0x1a0
#define XILINX_DP_TX_MAIN_STREAM_MISC0                  0x1a4
#define XILINX_DP_TX_MAIN_STREAM_MISC0_SYNC             (1 << 0)
#define XILINX_DP_TX_MAIN_STREAM_MISC0_FORMAT_SHIFT     1
#define XILINX_DP_TX_MAIN_STREAM_MISC0_DYNAMIC_RANGE    (1 << 3)
#define XILINX_DP_TX_MAIN_STREAM_MISC0_YCBCR_COLRIMETRY (1 << 4)
#define XILINX_DP_TX_MAIN_STREAM_MISC0_BPC_SHIFT        5
#define XILINX_DP_TX_MAIN_STREAM_MISC1                  0x1a8
#define XILINX_DP_TX_MAIN_STREAM_MISC0_INTERLACED_VERT  (1 << 0)
#define XILINX_DP_TX_MAIN_STREAM_MISC0_STEREO_VID_SHIFT 1
#define XILINX_DP_TX_M_VID                              0x1ac
#define XILINX_DP_TX_TRANSFER_UNIT_SIZE                 0x1b0
#define XILINX_DP_TX_DEF_TRANSFER_UNIT_SIZE             64
#define XILINX_DP_TX_N_VID                              0x1b4
#define XILINX_DP_TX_USER_PIXEL_WIDTH                   0x1b8
#define XILINX_DP_TX_USER_DATA_CNT_PER_LANE             0x1bc
#define XILINX_DP_TX_MIN_BYTES_PER_TU                   0x1c4
#define XILINX_DP_TX_FRAC_BYTES_PER_TU                  0x1c8
#define XILINX_DP_TX_INIT_WAIT                          0x1cc

/* PHY configuration and status registers */
#define XILINX_DP_TX_PHY_CONFIG                         0x200
#define XILINX_DP_TX_PHY_CONFIG_PHY_RESET               (1 << 0)
#define XILINX_DP_TX_PHY_CONFIG_GTTX_RESET              (1 << 1)
#define XILINX_DP_TX_PHY_CONFIG_PHY_PMA_RESET           (1 << 8)
#define XILINX_DP_TX_PHY_CONFIG_PHY_PCS_RESET           (1 << 9)
#define XILINX_DP_TX_PHY_CONFIG_ALL_RESET               (XILINX_DP_TX_PHY_CONFIG_PHY_RESET | \
                                                         XILINX_DP_TX_PHY_CONFIG_GTTX_RESET | \
                                                         XILINX_DP_TX_PHY_CONFIG_PHY_PMA_RESET | \
                                                         XILINX_DP_TX_PHY_CONFIG_PHY_PCS_RESET)
#define XILINX_DP_TX_PHY_PREEMPHASIS_LANE_0             0x210
#define XILINX_DP_TX_PHY_PREEMPHASIS_LANE_1             0x214
#define XILINX_DP_TX_PHY_PREEMPHASIS_LANE_2             0x218
#define XILINX_DP_TX_PHY_PREEMPHASIS_LANE_3             0x21c
#define XILINX_DP_TX_PHY_VOLTAGE_DIFF_LANE_0            0x220
#define XILINX_DP_TX_PHY_VOLTAGE_DIFF_LANE_1            0x224
#define XILINX_DP_TX_PHY_VOLTAGE_DIFF_LANE_2            0x228
#define XILINX_DP_TX_PHY_VOLTAGE_DIFF_LANE_3            0x22c
#define XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING         0x234
#define XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING_162     0x1
#define XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING_270     0x3
#define XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING_540     0x5
#define XILINX_DP_TX_PHY_POWER_DOWN                     0x238
#define XILINX_DP_TX_PHY_POWER_DOWN_LANE_0              (1 << 0)
#define XILINX_DP_TX_PHY_POWER_DOWN_LANE_1              (1 << 1)
#define XILINX_DP_TX_PHY_POWER_DOWN_LANE_2              (1 << 2)
#define XILINX_DP_TX_PHY_POWER_DOWN_LANE_3              (1 << 3)
#define XILINX_DP_TX_PHY_POWER_DOWN_ALL                 0xf
#define XILINX_DP_TX_PHY_PRECURSOR_LANE_0               0x23c
#define XILINX_DP_TX_PHY_PRECURSOR_LANE_1               0x240
#define XILINX_DP_TX_PHY_PRECURSOR_LANE_2               0x244
#define XILINX_DP_TX_PHY_PRECURSOR_LANE_3               0x248
#define XILINX_DP_TX_PHY_POSTCURSOR_LANE_0              0x24c
#define XILINX_DP_TX_PHY_POSTCURSOR_LANE_1              0x250
#define XILINX_DP_TX_PHY_POSTCURSOR_LANE_2              0x254
#define XILINX_DP_TX_PHY_POSTCURSOR_LANE_3              0x258
#define XILINX_DP_SUB_TX_PHY_PRECURSOR_LANE_0           0x24c
#define XILINX_DP_SUB_TX_PHY_PRECURSOR_LANE_1           0x250
#define XILINX_DP_TX_PHY_STATUS                         0x280
#define XILINX_DP_TX_PHY_STATUS_PLL_LOCKED_SHIFT        4
#define XILINX_DP_TX_PHY_STATUS_FPGA_PLL_LOCKED         (1 << 6)

/* Audio registers */
#define XILINX_DP_TX_AUDIO_CONTROL                      0x300
#define XILINX_DP_TX_AUDIO_CHANNELS                     0x304
#define XILINX_DP_TX_AUDIO_INFO_DATA                    0x308
#define XILINX_DP_TX_AUDIO_M_AUD                        0x328
#define XILINX_DP_TX_AUDIO_N_AUD                        0x32c
#define XILINX_DP_TX_AUDIO_EXT_DATA                     0x330

#define XILINX_DP_MISC0_RGB                             (0)
#define XILINX_DP_MISC0_YCRCB_422                       (5 << 1)
#define XILINX_DP_MISC0_YCRCB_444                       (6 << 1)
#define XILINX_DP_MISC0_BPC_6                           (0 << 5)
#define XILINX_DP_MISC0_BPC_8                           (1 << 5)
#define XILINX_DP_MISC0_BPC_10                          (2 << 5)
#define XILINX_DP_MISC0_BPC_12                          (3 << 5)
#define XILINX_DP_MISC0_BPC_16                          (4 << 5)
#define XILINX_DP_MISC1_Y_ONLY                          (1 << 7)

#define DP_REDUCED_BIT_RATE                             162000
#define DP_HIGH_BIT_RATE                                270000
#define DP_HIGH_BIT_RATE2                               540000
#define DP_MAX_TRAINING_TRIES                           5
#define DP_MAX_LANES                                    4

enum dp_version {
        DP_V1_1A = 0x11,
        DP_V1_2 = 0x12
};

/**
 * struct xilinx_drm_dp_link_config - Common link config between source and sink
 * @max_rate: maximum link rate
 * @max_lanes: maximum number of lanes
 */
struct xilinx_drm_dp_link_config {
        int max_rate;
        u8 max_lanes;
};

/**
 * struct xilinx_drm_dp_mode - Configured mode of DisplayPort
 * @bw_code: code for bandwidth(link rate)
 * @lane_cnt: number of lanes
 * @pclock: pixel clock frequency of current mode
 */
struct xilinx_drm_dp_mode {
        u8 bw_code;
        u8 lane_cnt;
        int pclock;
};

/**
 * struct xilinx_drm_dp_config - Configuration of DisplayPort from DTS
 * @dp_version: DisplayPort protocol version
 * @max_lanes: max number of lanes
 * @max_link_rate: max link rate
 * @max_bpc: maximum bits-per-color
 * @max_pclock: maximum pixel clock rate
 * @enable_yonly: enable yonly color space logic
 * @enable_ycrcb: enable ycrcb color space logic
 * @misc0: misc0 configuration (per DP v1.2 spec)
 * @misc1: misc1 configuration (per DP v1.2 spec)
 * @bpp: bits per pixel
 */
struct xilinx_drm_dp_config {
        enum dp_version dp_version;
        u32 max_lanes;
        u32 max_link_rate;
        u32 max_bpc;
        u32 max_pclock;
        bool enable_yonly;
        bool enable_ycrcb;

        u8 misc0;
        u8 misc1;
        u8 bpp;
};

/**
 * struct xilinx_drm_dp - Xilinx DisplayPort core
 * @encoder: pointer to the drm encoder structure
 * @dev: device structure
 * @iomem: device I/O memory for register access
 * @config: IP core configuration from DTS
 * @aux: aux channel
 * @dp_sub: DisplayPort subsystem
 * @phy: PHY handles for DP lanes
 * @aclk: clock source device for internal axi4-lite clock
 * @aud_clk: clock source device for audio clock
 * @dpms: current dpms state
 * @dpcd: DP configuration data from currently connected sink device
 * @link_config: common link configuration between IP core and sink device
 * @mode: current mode between IP core and sink device
 * @train_set: set of training data
 * @suspend: flag to set when going in suspend mode
 */
struct xilinx_drm_dp {
        struct drm_encoder *encoder;
        struct device *dev;
        void __iomem *iomem;

        struct xilinx_drm_dp_config config;
        struct drm_dp_aux aux;
        struct xilinx_drm_dp_sub *dp_sub;
        struct phy *phy[DP_MAX_LANES];
        struct clk *aclk;
        struct clk *aud_clk;

        int dpms;
        u8 dpcd[DP_RECEIVER_CAP_SIZE];
        struct xilinx_drm_dp_link_config link_config;
        struct xilinx_drm_dp_mode mode;
        u8 train_set[DP_MAX_LANES];
        bool suspend;
};

static inline struct xilinx_drm_dp *to_dp(struct drm_encoder *encoder)
{
        return to_encoder_slave(encoder)->slave_priv;
}

#define AUX_READ_BIT    0x1

/**
 * xilinx_drm_dp_aux_cmd_submit - Submit aux command
 * @dp: DisplayPort IP core structure
 * @cmd: aux command
 * @addr: aux address
 * @buf: buffer for command data
 * @bytes: number of bytes for @buf
 * @reply: reply code to be returned
 *
 * Submit an aux command. All aux related commands, native or i2c aux
 * read/write, are submitted through this function. The function is mapped to
 * the transfer function of struct drm_dp_aux. This function involves in
 * multiple register reads/writes, thus synchronization is needed, and it is
 * done by drm_dp_helper using @hw_mutex. The calling thread goes into sleep
 * if there's no immediate reply to the command submission. The reply code is
 * returned at @reply if @reply != NULL.
 *
 * Return: 0 if the command is submitted properly, or corresponding error code:
 * -EBUSY when there is any request already being processed
 * -ETIMEDOUT when receiving reply is timed out
 * -EIO when received bytes are less than requested
 */
static int xilinx_drm_dp_aux_cmd_submit(struct xilinx_drm_dp *dp, u32 cmd,
                                        u16 addr, u8 *buf, u8 bytes, u8 *reply)
{
        bool is_read = (cmd & AUX_READ_BIT) ? true : false;
        void __iomem *iomem = dp->iomem;
        u32 reg, i;

        reg = xilinx_drm_readl(iomem, XILINX_DP_TX_INTR_SIGNAL_STATE);
        if (reg & XILINX_DP_TX_INTR_SIGNAL_STATE_REQUEST)
                return -EBUSY;

        xilinx_drm_writel(iomem, XILINX_DP_TX_AUX_ADDRESS, addr);

        if (!is_read)
                for (i = 0; i < bytes; i++)
                        xilinx_drm_writel(iomem, XILINX_DP_TX_AUX_WRITE_FIFO,
                                          buf[i]);

        reg = cmd << XILINX_DP_TX_AUX_COMMAND_CMD_SHIFT;
        if (!buf || !bytes)
                reg |= XILINX_DP_TX_AUX_COMMAND_ADDRESS_ONLY;
        else
                reg |= (bytes - 1) << XILINX_DP_TX_AUX_COMMAND_BYTES_SHIFT;
        xilinx_drm_writel(iomem, XILINX_DP_TX_AUX_COMMAND, reg);

        /* Wait for reply to be delivered upto 2ms */
        for (i = 0; ; i++) {
                reg = xilinx_drm_readl(iomem, XILINX_DP_TX_INTR_SIGNAL_STATE);

                if (reg & XILINX_DP_TX_INTR_SIGNAL_STATE_REPLY)
                        break;

                if (reg & XILINX_DP_TX_INTR_SIGNAL_STATE_REPLY_TIMEOUT ||
                    i == 2)
                        return -ETIMEDOUT;

                usleep_range(1000, 1100);
        }

        reg = xilinx_drm_readl(iomem, XILINX_DP_TX_AUX_REPLY_CODE);
        if (reply)
                *reply = reg;

        if (is_read &&
            (reg == XILINX_DP_TX_AUX_REPLY_CODE_AUX_ACK ||
             reg == XILINX_DP_TX_AUX_REPLY_CODE_I2C_ACK)) {
                reg = xilinx_drm_readl(iomem, XILINX_DP_TX_REPLY_DATA_CNT);
                if ((reg & XILINX_DP_TX_AUX_REPLY_CNT_MASK) != bytes)
                        return -EIO;

                for (i = 0; i < bytes; i++)
                        buf[i] = xilinx_drm_readl(iomem,
                                                  XILINX_DP_TX_AUX_REPLY_DATA);
        }

        return 0;
}

/**
 * xilinx_drm_dp_phy_ready - Check if PHY is ready
 * @dp: DisplayPort IP core structure
 *
 * Check if PHY is ready. If PHY is not ready, wait 1ms to check for 100 times.
 * This amount of delay was suggested by IP designer.
 *
 * Return: 0 if PHY is ready, or -ENODEV if PHY is not ready.
 */
static int xilinx_drm_dp_phy_ready(struct xilinx_drm_dp *dp)
{
        u32 i, reg, ready, lane;

        lane = dp->config.max_lanes;
        ready = (1 << lane) - 1;
        if (!dp->dp_sub)
                ready |= XILINX_DP_TX_PHY_STATUS_FPGA_PLL_LOCKED;

        /* Wait for 100 * 1ms. This should be enough time for PHY to be ready */
        for (i = 0; ; i++) {
                reg = xilinx_drm_readl(dp->iomem, XILINX_DP_TX_PHY_STATUS);
                if ((reg & ready) == ready)
                        return 0;

                if (i == 100) {
                        DRM_ERROR("PHY isn't ready\n");
                        return -ENODEV;
                }

                usleep_range(1000, 1100);
        }

        return 0;
}

/**
 * xilinx_drm_dp_max_rate - Calculate and return available max pixel clock
 * @link_rate: link rate (Kilo-bytes / sec)
 * @lane_num: number of lanes
 * @bpp: bits per pixel
 *
 * Return: max pixel clock (KHz) supported by current link config.
 */
static inline int xilinx_drm_dp_max_rate(int link_rate, u8 lane_num, u8 bpp)
{
        return link_rate * lane_num * 8 / bpp;
}

/**
 * xilinx_drm_dp_mode_configure - Configure the link values
 * @dp: DisplayPort IP core structure
 * @pclock: pixel clock for requested display mode
 * @current_bw: current link rate
 *
 * Find the link configuration values, rate and lane count for requested pixel
 * clock @pclock. The @pclock is stored in the mode to be used in other
 * functions later. The returned rate is downshifted from the current rate
 * @current_bw.
 *
 * Return: Current link rate code, or -EINVAL.
 */
static int xilinx_drm_dp_mode_configure(struct xilinx_drm_dp *dp, int pclock,
                                        u8 current_bw)
{
        int max_rate = dp->link_config.max_rate;
        u8 bws[3] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7, DP_LINK_BW_5_4 };
        u8 max_lanes = dp->link_config.max_lanes;
        u8 max_link_rate_code = drm_dp_link_rate_to_bw_code(max_rate);
        u8 bpp = dp->config.bpp;
        u8 lane_cnt;
        s8 clock, i;

        for (i = ARRAY_SIZE(bws) - 1; i >= 0; i--) {
                if (current_bw && bws[i] >= current_bw)
                        continue;

                if (bws[i] <= max_link_rate_code)
                        break;
        }

        for (lane_cnt = 1; lane_cnt <= max_lanes; lane_cnt <<= 1) {
                for (clock = i; clock >= 0; clock--) {
                        int bw;
                        u32 rate;

                        bw = drm_dp_bw_code_to_link_rate(bws[clock]);
                        rate = xilinx_drm_dp_max_rate(bw, lane_cnt, bpp);
                        if (pclock <= rate) {
                                dp->mode.bw_code = bws[clock];
                                dp->mode.lane_cnt = lane_cnt;
                                dp->mode.pclock = pclock;
                                return bws[clock];
                        }
                }
        }

        DRM_ERROR("failed to configure link values\n");

        return -EINVAL;
}

/**
 * xilinx_drm_dp_adjust_train - Adjust train values
 * @dp: DisplayPort IP core structure
 * @link_status: link status from sink which contains requested training values
 */
static void xilinx_drm_dp_adjust_train(struct xilinx_drm_dp *dp,
                                       u8 link_status[DP_LINK_STATUS_SIZE])
{
        u8 *train_set = dp->train_set;
        u8 voltage = 0, preemphasis = 0;
        u8 max_preemphasis;
        u8 i;

        for (i = 0; i < dp->mode.lane_cnt; i++) {
                u8 v = drm_dp_get_adjust_request_voltage(link_status, i);
                u8 p = drm_dp_get_adjust_request_pre_emphasis(link_status, i);

                if (v > voltage)
                        voltage = v;

                if (p > preemphasis)
                        preemphasis = p;
        }

        if (voltage >= DP_TRAIN_VOLTAGE_SWING_LEVEL_3)
                voltage |= DP_TRAIN_MAX_SWING_REACHED;

        max_preemphasis = (dp->dp_sub) ? DP_TRAIN_PRE_EMPH_LEVEL_2 :
                                         DP_TRAIN_PRE_EMPH_LEVEL_3;

        if (preemphasis >= max_preemphasis)
                preemphasis |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;

        for (i = 0; i < dp->mode.lane_cnt; i++)
                train_set[i] = voltage | preemphasis;
}

/**
 * xilinx_drm_dp_update_vs_emph - Update the training values
 * @dp: DisplayPort IP core structure
 *
 * Update the training values based on the request from sink. The mapped values
 * are predefined, and values(vs, pe, pc) are from the device manual.
 *
 * Return: 0 if vs and emph are updated successfully, or the error code returned
 * by drm_dp_dpcd_write().
 */
static int xilinx_drm_dp_update_vs_emph(struct xilinx_drm_dp *dp)
{
        u8 *train_set = dp->train_set;
        u8 i, v_level, p_level;
        int ret;
        static u8 vs[4][4] = { { 0x2a, 0x27, 0x24, 0x20 },
                               { 0x27, 0x23, 0x20, 0xff },
                               { 0x24, 0x20, 0xff, 0xff },
                               { 0xff, 0xff, 0xff, 0xff } };
        static u8 pe[4][4] = { { 0x2, 0x2, 0x2, 0x2 },
                               { 0x1, 0x1, 0x1, 0xff },
                               { 0x0, 0x0, 0xff, 0xff },
                               { 0xff, 0xff, 0xff, 0xff } };

        ret = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET, train_set,
                                dp->mode.lane_cnt);
        if (ret < 0)
                return ret;

        for (i = 0; i < dp->mode.lane_cnt; i++) {
                v_level = (train_set[i] & DP_TRAIN_VOLTAGE_SWING_MASK) >>
                          DP_TRAIN_VOLTAGE_SWING_SHIFT;
                p_level = (train_set[i] & DP_TRAIN_PRE_EMPHASIS_MASK) >>
                          DP_TRAIN_PRE_EMPHASIS_SHIFT;

                if (dp->phy[i]) {
                        u32 reg = XILINX_DP_SUB_TX_PHY_PRECURSOR_LANE_0 + i * 4;

                        xpsgtr_margining_factor(dp->phy[i], p_level, v_level);
                        xpsgtr_override_deemph(dp->phy[i], p_level, v_level);
                        xilinx_drm_writel(dp->iomem, reg, 0x2);
                } else {
                        u32 reg;

                        reg = XILINX_DP_TX_PHY_VOLTAGE_DIFF_LANE_0 + i + 4;
                        xilinx_drm_writel(dp->iomem, reg, vs[p_level][v_level]);
                        reg = XILINX_DP_TX_PHY_PRECURSOR_LANE_0 + i + 4;
                        xilinx_drm_writel(dp->iomem, reg, pe[p_level][v_level]);
                        reg = XILINX_DP_TX_PHY_POSTCURSOR_LANE_0 + i + 4;
                        xilinx_drm_writel(dp->iomem, reg, 0);
                }
        }

        return 0;
}

/**
 * xilinx_drm_dp_link_train_cr - Train clock recovery
 * @dp: DisplayPort IP core structure
 *
 * Return: 0 if clock recovery train is done successfully, or corresponding
 * error code.
 */
static int xilinx_drm_dp_link_train_cr(struct xilinx_drm_dp *dp)
{
        u8 link_status[DP_LINK_STATUS_SIZE];
        u8 lane_cnt = dp->mode.lane_cnt;
        u8 vs = 0, tries = 0;
        u16 max_tries, i;
        bool cr_done;
        int ret;

        ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
                                 DP_TRAINING_PATTERN_1 |
                                 DP_LINK_SCRAMBLING_DISABLE);
        if (ret < 0)
                return ret;

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_TRAINING_PATTERN_SET,
                          DP_TRAINING_PATTERN_1);

        /* 256 loops should be maximum iterations for 4 lanes and 4 values.
         * So, This loop should exit before 512 iterations */
        for (max_tries = 0; max_tries < 512; max_tries++) {
                ret = xilinx_drm_dp_update_vs_emph(dp);
                if (ret)
                        return ret;

                drm_dp_link_train_clock_recovery_delay(dp->dpcd);

                ret = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
                if (ret < 0)
                        return ret;

                cr_done = drm_dp_clock_recovery_ok(link_status, lane_cnt);
                if (cr_done)
                        break;

                for (i = 0; i < lane_cnt; i++)
                        if (!(dp->train_set[i] & DP_TRAIN_MAX_SWING_REACHED))
                                break;

                if (i == lane_cnt)
                        break;

                if ((dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == vs)
                        tries++;
                else
                        tries = 0;

                if (tries == DP_MAX_TRAINING_TRIES)
                        break;

                vs = dp->train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;

                xilinx_drm_dp_adjust_train(dp, link_status);
        }

        if (!cr_done)
                return -EIO;

        return 0;
}

/**
 * xilinx_drm_dp_link_train_ce - Train channel equalization
 * @dp: DisplayPort IP core structure
 *
 * Return: 0 if channel equalization train is done successfully, or
 * corresponding error code.
 */
static int xilinx_drm_dp_link_train_ce(struct xilinx_drm_dp *dp)
{
        u8 link_status[DP_LINK_STATUS_SIZE];
        u8 lane_cnt = dp->mode.lane_cnt;
        u32 pat, tries;
        int ret;
        bool ce_done;

        if (dp->config.dp_version == DP_V1_2 &&
            dp->dpcd[DP_DPCD_REV] >= DP_V1_2 &&
            dp->dpcd[DP_MAX_LANE_COUNT] & DP_TPS3_SUPPORTED)
                pat = DP_TRAINING_PATTERN_3;
        else
                pat = DP_TRAINING_PATTERN_2;

        ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
                                 pat | DP_LINK_SCRAMBLING_DISABLE);
        if (ret < 0)
                return ret;

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_TRAINING_PATTERN_SET, pat);

        for (tries = 0; tries < DP_MAX_TRAINING_TRIES; tries++) {
                ret = xilinx_drm_dp_update_vs_emph(dp);
                if (ret)
                        return ret;

                drm_dp_link_train_channel_eq_delay(dp->dpcd);

                ret = drm_dp_dpcd_read_link_status(&dp->aux, link_status);
                if (ret < 0)
                        return ret;

                ce_done = drm_dp_channel_eq_ok(link_status, lane_cnt);
                if (ce_done)
                        break;

                xilinx_drm_dp_adjust_train(dp, link_status);
        }

        if (!ce_done)
                return -EIO;

        return 0;
}

/**
 * xilinx_drm_dp_link_train - Train the link
 * @dp: DisplayPort IP core structure
 *
 * Return: 0 if all trains are done successfully, or corresponding error code.
 */
static int xilinx_drm_dp_train(struct xilinx_drm_dp *dp)
{
        u32 reg;
        u8 bw_code = dp->mode.bw_code;
        u8 lane_cnt = dp->mode.lane_cnt;
        u8 aux_lane_cnt = lane_cnt;
        bool enhanced;
        int ret;

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_LANE_CNT_SET, lane_cnt);

        enhanced = drm_dp_enhanced_frame_cap(dp->dpcd);
        if (enhanced) {
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_ENHANCED_FRAME_EN, 1);
                aux_lane_cnt |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
        }

        if (dp->dpcd[3] & 0x1) {
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_DOWNSPREAD_CTL, 1);
                drm_dp_dpcd_writeb(&dp->aux, DP_DOWNSPREAD_CTRL,
                                   DP_SPREAD_AMP_0_5);
        } else {
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_DOWNSPREAD_CTL, 0);
                drm_dp_dpcd_writeb(&dp->aux, DP_DOWNSPREAD_CTRL, 0);
        }

        ret = drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET, aux_lane_cnt);
        if (ret < 0) {
                DRM_ERROR("failed to set lane count\n");
                return ret;
        }

        ret = drm_dp_dpcd_writeb(&dp->aux, DP_MAIN_LINK_CHANNEL_CODING_SET,
                                 DP_SET_ANSI_8B10B);
        if (ret < 0) {
                DRM_ERROR("failed to set ANSI 8B/10B encoding\n");
                return ret;
        }

        ret = drm_dp_dpcd_writeb(&dp->aux, DP_LINK_BW_SET, bw_code);
        if (ret < 0) {
                DRM_ERROR("failed to set DP bandwidth\n");
                return ret;
        }

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_LINK_BW_SET, bw_code);

        switch (bw_code) {
        case DP_LINK_BW_1_62:
                reg = XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING_162;
                break;
        case DP_LINK_BW_2_7:
                reg = XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING_270;
                break;
        case DP_LINK_BW_5_4:
        default:
                reg = XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING_540;
                break;
        }

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_PHY_CLOCK_FEEDBACK_SETTING,
                          reg);
        ret = xilinx_drm_dp_phy_ready(dp);
        if (ret < 0)
                return ret;

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_SCRAMBLING_DISABLE, 1);

        memset(dp->train_set, 0, 4);

        ret = xilinx_drm_dp_link_train_cr(dp);
        if (ret)
                return ret;

        ret = xilinx_drm_dp_link_train_ce(dp);
        if (ret)
                return ret;

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_TRAINING_PATTERN_SET,
                          DP_TRAINING_PATTERN_DISABLE);
        ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
                                 DP_TRAINING_PATTERN_DISABLE);
        if (ret < 0) {
                DRM_ERROR("failed to disable training pattern\n");
                return ret;
        }

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_SCRAMBLING_DISABLE, 0);

        return 0;
}

/**
 * xilinx_drm_dp_train_loop - Downshift the link rate during training
 * @dp: DisplayPort IP core structure
 *
 * Train the link by downshifting the link rate if training is not successful.
 */
static void xilinx_drm_dp_train_loop(struct xilinx_drm_dp *dp)
{
        struct xilinx_drm_dp_mode *mode = &dp->mode;
        u8 bw = mode->bw_code;
        int ret;

        do {
                ret = xilinx_drm_dp_train(dp);
                if (!ret)
                        return;

                ret = xilinx_drm_dp_mode_configure(dp, mode->pclock, bw);
                if (ret < 0)
                        return;
                bw = ret;
        } while (bw >= DP_LINK_BW_1_62);

        DRM_ERROR("failed to train the DP link\n");
}

/**
 * xilinx_drm_dp_init_aux - Initialize the DP aux
 * @dp: DisplayPort IP core structure
 *
 * Initialize the DP aux. The aux clock is derived from the axi clock, so
 * this function gets the axi clock frequency and calculates the filter
 * value. Additionally, the interrupts and transmitter are enabled.
 *
 * Return: 0 on success, error value otherwise
 */
static int xilinx_drm_dp_init_aux(struct xilinx_drm_dp *dp)
{
        int clock_rate;
        u32 reg, w;

        clock_rate = clk_get_rate(dp->aclk);
        if (clock_rate < XILINX_DP_TX_CLK_DIVIDER_MHZ) {
                DRM_ERROR("aclk should be higher than 1MHz\n");
                return -EINVAL;
        }

        /* Allowable values for this register are: 8, 16, 24, 32, 40, 48 */
        for (w = 8; w <= 48; w += 8) {
                /* AUX pulse width should be between 0.4 to 0.6 usec */
                if (w >= (4 * clock_rate / 10000000) &&
                    w <= (6 * clock_rate / 10000000))
                        break;
        }

        if (w > 48) {
                DRM_ERROR("aclk frequency too high\n");
                return -EINVAL;
        }
        reg = w << XILINX_DP_TX_CLK_DIVIDER_AUX_FILTER_SHIFT;

        reg |= clock_rate / XILINX_DP_TX_CLK_DIVIDER_MHZ;
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_CLK_DIVIDER, reg);

        if (dp->dp_sub)
                xilinx_drm_writel(dp->iomem, XILINX_DP_SUB_TX_INTR_EN,
                                  XILINX_DP_TX_INTR_ALL);
        else
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_INTR_MASK,
                                  ~XILINX_DP_TX_INTR_ALL);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_ENABLE, 1);

        return 0;
}

/**
 * xilinx_drm_dp_init_phy - Initialize the phy
 * @dp: DisplayPort IP core structure
 *
 * Initialize the phy.
 *
 * Return: 0 if the phy instances are initialized correctly, or the error code
 * returned from the callee functions.
 */
static int xilinx_drm_dp_init_phy(struct xilinx_drm_dp *dp)
{
        unsigned int i;
        int ret;

        for (i = 0; i < dp->config.max_lanes; i++) {
                ret = phy_init(dp->phy[i]);
                if (ret) {
                        dev_err(dp->dev, "failed to init phy lane %d\n", i);
                        return ret;
                }
        }

        if (dp->dp_sub)
                xilinx_drm_writel(dp->iomem, XILINX_DP_SUB_TX_INTR_DS,
                                  XILINX_DP_TX_INTR_ALL);
        else
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_INTR_MASK,
                                  XILINX_DP_TX_INTR_ALL);

        xilinx_drm_clr(dp->iomem, XILINX_DP_TX_PHY_CONFIG,
                       XILINX_DP_TX_PHY_CONFIG_ALL_RESET);

        /* Wait for PLL to be locked for the primary (1st) */
        if (dp->phy[0]) {
                ret = xpsgtr_wait_pll_lock(dp->phy[0]);
                if (ret) {
                        dev_err(dp->dev, "failed to lock pll\n");
                        return ret;
                }
        }

        return 0;
}

/**
 * xilinx_drm_dp_exit_phy - Exit the phy
 * @dp: DisplayPort IP core structure
 *
 * Exit the phy.
 */
static void xilinx_drm_dp_exit_phy(struct xilinx_drm_dp *dp)
{
        unsigned int i;
        int ret;

        for (i = 0; i < dp->config.max_lanes; i++) {
                ret = phy_exit(dp->phy[i]);
                if (ret) {
                        dev_err(dp->dev,
                                "failed to exit phy (%d) %d\n", i, ret);
                }
        }
}

static void xilinx_drm_dp_dpms(struct drm_encoder *encoder, int dpms)
{
        struct xilinx_drm_dp *dp = to_dp(encoder);
        void __iomem *iomem = dp->iomem;
        unsigned int i;
        int ret;

        if (dp->dpms == dpms)
                return;

        dp->dpms = dpms;

        switch (dpms) {
        case DRM_MODE_DPMS_ON:
                pm_runtime_get_sync(dp->dev);

                if (dp->suspend) {
                        xilinx_drm_dp_init_phy(dp);
                        xilinx_drm_dp_init_aux(dp);
                        dp->suspend = false;
                }

                if (dp->aud_clk)
                        xilinx_drm_writel(iomem, XILINX_DP_TX_AUDIO_CONTROL, 1);
                xilinx_drm_writel(iomem, XILINX_DP_TX_PHY_POWER_DOWN, 0);

                for (i = 0; i < 3; i++) {

                        ret = drm_dp_dpcd_writeb(&dp->aux, DP_SET_POWER,
                                                 DP_SET_POWER_D0);
                        if (ret == 1)
                                break;
                        usleep_range(300, 500);
                }
                xilinx_drm_dp_train_loop(dp);
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_SW_RESET,
                                  XILINX_DP_TX_SW_RESET_ALL);
                xilinx_drm_writel(iomem, XILINX_DP_TX_ENABLE_MAIN_STREAM, 1);

                return;
        case DRM_MODE_DPMS_SUSPEND:
                dp->suspend = true;
                xilinx_drm_dp_exit_phy(dp);
        default:
                xilinx_drm_writel(iomem, XILINX_DP_TX_ENABLE_MAIN_STREAM, 0);
                drm_dp_dpcd_writeb(&dp->aux, DP_SET_POWER, DP_SET_POWER_D3);
                xilinx_drm_writel(iomem, XILINX_DP_TX_PHY_POWER_DOWN,
                                  XILINX_DP_TX_PHY_POWER_DOWN_ALL);
                if (dp->aud_clk)
                        xilinx_drm_writel(iomem, XILINX_DP_TX_AUDIO_CONTROL, 0);

                pm_runtime_put_sync(dp->dev);

                return;
        }
}

static void xilinx_drm_dp_save(struct drm_encoder *encoder)
{
        /* no op */
}

static void xilinx_drm_dp_restore(struct drm_encoder *encoder)
{
        /* no op */
}

#define XILINX_DP_SUB_TX_MIN_H_BACKPORCH        20

static bool xilinx_drm_dp_mode_fixup(struct drm_encoder *encoder,
                                     const struct drm_display_mode *mode,
                                     struct drm_display_mode *adjusted_mode)
{
        struct xilinx_drm_dp *dp = to_dp(encoder);
        int diff = mode->htotal - mode->hsync_end;

        /*
         * ZynqMP DP requires horizontal backporch to be greater than 12.
         * This limitation may conflict with the sink device.
         */
        if (dp->dp_sub && diff < XILINX_DP_SUB_TX_MIN_H_BACKPORCH) {
                int vrefresh = (adjusted_mode->clock * 1000) /
                               (adjusted_mode->vtotal * adjusted_mode->htotal);

                diff = XILINX_DP_SUB_TX_MIN_H_BACKPORCH - diff;
                adjusted_mode->htotal += diff;
                adjusted_mode->clock = adjusted_mode->vtotal *
                                       adjusted_mode->htotal * vrefresh / 1000;
        }

        return true;
}

static int xilinx_drm_dp_mode_valid(struct drm_encoder *encoder,
                                    struct drm_display_mode *mode)
{
        struct xilinx_drm_dp *dp = to_dp(encoder);
        u8 max_lanes = dp->link_config.max_lanes;
        u8 bpp = dp->config.bpp;
        u32 max_pclock = dp->config.max_pclock;
        int max_rate = dp->link_config.max_rate;
        int rate;

        if (max_pclock && mode->clock > max_pclock)
                return MODE_CLOCK_HIGH;

        rate = xilinx_drm_dp_max_rate(max_rate, max_lanes, bpp);
        if (mode->clock > rate)
                return MODE_CLOCK_HIGH;

        return MODE_OK;
}

/**
 * xilinx_drm_dp_mode_set_transfer_unit - Set the transfer unit values
 * @dp: DisplayPort IP core structure
 * @mode: requested display mode
 *
 * Set the transfer unit, and caculate all transfer unit size related values.
 * Calculation is based on DP and IP core specification.
 */
static void xilinx_drm_dp_mode_set_transfer_unit(struct xilinx_drm_dp *dp,
                                                 struct drm_display_mode *mode)
{
        u32 tu = XILINX_DP_TX_DEF_TRANSFER_UNIT_SIZE;
        u32 bw, vid_kbytes, avg_bytes_per_tu, init_wait;

        /* Use the max transfer unit size (default) */
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_TRANSFER_UNIT_SIZE, tu);

        vid_kbytes = mode->clock * (dp->config.bpp / 8);
        bw = drm_dp_bw_code_to_link_rate(dp->mode.bw_code);
        avg_bytes_per_tu = vid_kbytes * tu / (dp->mode.lane_cnt * bw / 1000);

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MIN_BYTES_PER_TU,
                          avg_bytes_per_tu / 1000);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_FRAC_BYTES_PER_TU,
                          avg_bytes_per_tu % 1000);

        /* Configure the initial wait cycle based on transfer unit size */
        if (tu < (avg_bytes_per_tu / 1000))
                init_wait = 0;
        else if ((avg_bytes_per_tu / 1000) <= 4)
                init_wait = tu;
        else
                init_wait = tu - avg_bytes_per_tu / 1000;

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_INIT_WAIT, init_wait);
}

/**
 * xilinx_drm_dp_mode_set_stream - Configure the main stream
 * @dp: DisplayPort IP core structure
 * @mode: requested display mode
 *
 * Configure the main stream based on the requested mode @mode. Calculation is
 * based on IP core specification.
 */
static void xilinx_drm_dp_mode_set_stream(struct xilinx_drm_dp *dp,
                                          struct drm_display_mode *mode)
{
        u8 lane_cnt = dp->mode.lane_cnt;
        u32 reg, wpl;

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_HTOTAL,
                          mode->htotal);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_VTOTAL,
                          mode->vtotal);

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_POLARITY,
                          (!!(mode->flags & DRM_MODE_FLAG_PVSYNC) <<
                           XILINX_DP_TX_MAIN_STREAM_POLARITY_VSYNC_SHIFT) |
                          (!!(mode->flags & DRM_MODE_FLAG_PHSYNC) <<
                           XILINX_DP_TX_MAIN_STREAM_POLARITY_HSYNC_SHIFT));

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_HSWIDTH,
                          mode->hsync_end - mode->hsync_start);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_VSWIDTH,
                          mode->vsync_end - mode->vsync_start);

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_HRES,
                          mode->hdisplay);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_VRES,
                          mode->vdisplay);

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_HSTART,
                          mode->htotal - mode->hsync_start);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_VSTART,
                          mode->vtotal - mode->vsync_start);

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_MISC0,
                          dp->config.misc0);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_MAIN_STREAM_MISC1,
                          dp->config.misc1);

        /* In synchronous mode, set the diviers */
        if (dp->config.misc0 & XILINX_DP_TX_MAIN_STREAM_MISC0_SYNC) {
                reg = drm_dp_bw_code_to_link_rate(dp->mode.bw_code);
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_N_VID, reg);
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_M_VID, mode->clock);
                if (dp->aud_clk) {
                        int aud_rate = clk_get_rate(dp->aud_clk) / 512;

                        if (aud_rate != 44100 && aud_rate != 48000)
                                dev_dbg(dp->dev, "Audio rate: %d\n", aud_rate);

                        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_AUDIO_N_AUD,
                                          reg);
                        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_AUDIO_M_AUD,
                                          aud_rate);
                }
        }

        /* Only 2 channel is supported now */
        if (dp->aud_clk)
                xilinx_drm_writel(dp->iomem, XILINX_DP_TX_AUDIO_CHANNELS, 1);

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_USER_PIXEL_WIDTH, 1);

        /* Translate to the native 16 bit datapath based on IP core spec */
        wpl = (mode->hdisplay * dp->config.bpp + 15) / 16;
        reg = wpl + wpl % lane_cnt - lane_cnt;
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_USER_DATA_CNT_PER_LANE, reg);
}


static void xilinx_drm_dp_mode_set(struct drm_encoder *encoder,
                                   struct drm_display_mode *mode,
                                   struct drm_display_mode *adjusted_mode)
{
        struct xilinx_drm_dp *dp = to_dp(encoder);
        int ret;

        ret = xilinx_drm_dp_mode_configure(dp, adjusted_mode->clock, 0);
        if (ret < 0)
                return;

        xilinx_drm_dp_mode_set_stream(dp, adjusted_mode);
        xilinx_drm_dp_mode_set_transfer_unit(dp, adjusted_mode);
}

static enum drm_connector_status
xilinx_drm_dp_detect(struct drm_encoder *encoder,
                     struct drm_connector *connector)
{
        struct xilinx_drm_dp *dp = to_dp(encoder);
        struct xilinx_drm_dp_link_config *link_config = &dp->link_config;
        u32 state;
        int ret;

        state = xilinx_drm_readl(dp->iomem, XILINX_DP_TX_INTR_SIGNAL_STATE);
        if (state & XILINX_DP_TX_INTR_SIGNAL_STATE_HPD) {
                ret = drm_dp_dpcd_read(&dp->aux, 0x0, dp->dpcd,
                                       sizeof(dp->dpcd));
                if (ret < 0)
                        return connector_status_disconnected;

                link_config->max_rate = min_t(int,
                                              drm_dp_max_link_rate(dp->dpcd),
                                              dp->config.max_link_rate);
                link_config->max_lanes = min_t(u8,
                                               drm_dp_max_lane_count(dp->dpcd),
                                               dp->config.max_lanes);

                return connector_status_connected;
        }

        return connector_status_disconnected;
}

static int xilinx_drm_dp_get_modes(struct drm_encoder *encoder,
                                   struct drm_connector *connector)
{
        struct xilinx_drm_dp *dp = to_dp(encoder);
        struct edid *edid;
        int ret;

        edid = drm_get_edid(connector, &dp->aux.ddc);
        if (!edid)
                return 0;

        drm_mode_connector_update_edid_property(connector, edid);
        ret = drm_add_edid_modes(connector, edid);

        kfree(edid);

        return ret;
}

static struct drm_encoder_slave_funcs xilinx_drm_dp_encoder_funcs = {
        .dpms                   = xilinx_drm_dp_dpms,
        .save                   = xilinx_drm_dp_save,
        .restore                = xilinx_drm_dp_restore,
        .mode_fixup             = xilinx_drm_dp_mode_fixup,
        .mode_valid             = xilinx_drm_dp_mode_valid,
        .mode_set               = xilinx_drm_dp_mode_set,
        .detect                 = xilinx_drm_dp_detect,
        .get_modes              = xilinx_drm_dp_get_modes,
};

static int xilinx_drm_dp_encoder_init(struct platform_device *pdev,
                                      struct drm_device *dev,
                                      struct drm_encoder_slave *encoder)
{
        struct xilinx_drm_dp *dp = platform_get_drvdata(pdev);

        encoder->slave_priv = dp;
        encoder->slave_funcs = &xilinx_drm_dp_encoder_funcs;

        dp->encoder = &encoder->base;

        return xilinx_drm_dp_init_aux(dp);
}

static irqreturn_t xilinx_drm_dp_irq_handler(int irq, void *data)
{
        struct xilinx_drm_dp *dp = (struct xilinx_drm_dp *)data;
        u32 reg, status;

        reg = dp->dp_sub ?
              XILINX_DP_SUB_TX_INTR_STATUS : XILINX_DP_TX_INTR_STATUS;
        status = xilinx_drm_readl(dp->iomem, reg);
        if (!status)
                return IRQ_NONE;

        if (status & XILINX_DP_TX_INTR_CHBUF_UNDERFLW_MASK)
                dev_dbg(dp->dev, "underflow interrupt\n");
        if (status & XILINX_DP_TX_INTR_CHBUF_OVERFLW_MASK)
                dev_dbg(dp->dev, "overflow interrupt\n");

        xilinx_drm_writel(dp->iomem, reg, status);

        if (status & XILINX_DP_TX_INTR_VBLANK_START)
                xilinx_drm_dp_sub_handle_vblank(dp->dp_sub);

        if (status & XILINX_DP_TX_INTR_HPD_EVENT)
                drm_helper_hpd_irq_event(dp->encoder->dev);

        if (status & XILINX_DP_TX_INTR_HPD_IRQ) {
                u8 status[DP_LINK_STATUS_SIZE + 2];

                drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
                                 DP_LINK_STATUS_SIZE + 2);

                if (status[4] & DP_LINK_STATUS_UPDATED ||
                    !drm_dp_clock_recovery_ok(&status[2], dp->mode.lane_cnt) ||
                    !drm_dp_channel_eq_ok(&status[2], dp->mode.lane_cnt))
                        xilinx_drm_dp_train_loop(dp);
        }

        return IRQ_HANDLED;
}

static ssize_t
xilinx_drm_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
{
        struct xilinx_drm_dp *dp = container_of(aux, struct xilinx_drm_dp, aux);
        int ret;
        unsigned int i, iter;

        /* Number of loops = timeout in msec / aux delay (400 usec) */
        iter = xilinx_drm_dp_aux_timeout_ms * 1000 / 400;
        iter = iter ? iter : 1;

        for (i = 0; i < iter; i++) {
                ret = xilinx_drm_dp_aux_cmd_submit(dp, msg->request,
                                                   msg->address, msg->buffer,
                                                   msg->size, &msg->reply);
                if (!ret) {
                        dev_dbg(dp->dev, "aux %d retries\n", i);
                        return msg->size;
                }

                usleep_range(400, 500);
        }

        dev_dbg(dp->dev, "failed to do aux transfer (%d)\n", ret);

        return ret;
}

static int xilinx_drm_dp_parse_of(struct xilinx_drm_dp *dp)
{
        struct device_node *node = dp->dev->of_node;
        struct xilinx_drm_dp_config *config = &dp->config;
        const char *string;
        u32 num_colors, bpc;
        bool sync;
        int ret;

        ret = of_property_read_string(node, "xlnx,dp-version", &string);
        if (ret < 0) {
                dev_err(dp->dev, "No DP version in DT\n");
                return ret;
        }

        if (strcmp(string, "v1.1a") == 0) {
                config->dp_version = DP_V1_1A;
        } else if (strcmp(string, "v1.2") == 0) {
                config->dp_version = DP_V1_2;
        } else {
                dev_err(dp->dev, "Invalid DP version in DT\n");
                return -EINVAL;
        }

        ret = of_property_read_u32(node, "xlnx,max-lanes", &config->max_lanes);
        if (ret < 0) {
                dev_err(dp->dev, "No lane count in DT\n");
                return ret;
        }

        if (config->max_lanes != 1 && config->max_lanes != 2 &&
            config->max_lanes != 4) {
                dev_err(dp->dev, "Invalid max lanes in DT\n");
                return -EINVAL;
        }

        ret = of_property_read_u32(node, "xlnx,max-link-rate",
                                   &config->max_link_rate);
        if (ret < 0) {
                dev_err(dp->dev, "No link rate in DT\n");
                return ret;
        }

        if (config->max_link_rate != DP_REDUCED_BIT_RATE &&
            config->max_link_rate != DP_HIGH_BIT_RATE &&
            config->max_link_rate != DP_HIGH_BIT_RATE2) {
                dev_err(dp->dev, "Invalid link rate in DT\n");
                return -EINVAL;
        }

        config->enable_yonly = of_property_read_bool(node, "xlnx,enable-yonly");
        config->enable_ycrcb = of_property_read_bool(node, "xlnx,enable-ycrcb");

        sync = of_property_read_bool(node, "xlnx,sync");
        if (sync)
                config->misc0 |= XILINX_DP_TX_MAIN_STREAM_MISC0_SYNC;

        ret = of_property_read_string(node, "xlnx,colormetry", &string);
        if (ret < 0) {
                dev_err(dp->dev, "No colormetry in DT\n");
                return ret;
        }

        if (strcmp(string, "rgb") == 0) {
                config->misc0 |= XILINX_DP_MISC0_RGB;
                num_colors = 3;
        } else if (config->enable_ycrcb && strcmp(string, "ycrcb422") == 0) {
                config->misc0 |= XILINX_DP_MISC0_YCRCB_422;
                num_colors = 2;
        } else if (config->enable_ycrcb && strcmp(string, "ycrcb444") == 0) {
                config->misc0 |= XILINX_DP_MISC0_YCRCB_444;
                num_colors = 3;
        } else if (config->enable_yonly && strcmp(string, "yonly") == 0) {
                config->misc1 |= XILINX_DP_MISC1_Y_ONLY;
                num_colors = 1;
        } else {
                dev_err(dp->dev, "Invalid colormetry in DT\n");
                return -EINVAL;
        }

        ret = of_property_read_u32(node, "xlnx,max-bpc", &config->max_bpc);
        if (ret < 0) {
                dev_err(dp->dev, "No max bpc in DT\n");
                return ret;
        }

        if (config->max_bpc != 8 && config->max_bpc != 10 &&
            config->max_bpc != 12 && config->max_bpc != 16) {
                dev_err(dp->dev, "Invalid max bpc in DT\n");
                return -EINVAL;
        }

        ret = of_property_read_u32(node, "xlnx,bpc", &bpc);
        if (ret < 0) {
                dev_err(dp->dev, "No color depth(bpc) in DT\n");
                return ret;
        }

        if (bpc > config->max_bpc) {
                dev_err(dp->dev, "Invalid color depth(bpc) in DT\n");
                return -EINVAL;
        }

        switch (bpc) {
        case 6:
                config->misc0 |= XILINX_DP_MISC0_BPC_6;
                break;
        case 8:
                config->misc0 |= XILINX_DP_MISC0_BPC_8;
                break;
        case 10:
                config->misc0 |= XILINX_DP_MISC0_BPC_10;
                break;
        case 12:
                config->misc0 |= XILINX_DP_MISC0_BPC_12;
                break;
        case 16:
                config->misc0 |= XILINX_DP_MISC0_BPC_16;
                break;
        default:
                dev_err(dp->dev, "Not supported color depth in DT\n");
                return -EINVAL;
        }

        config->bpp = num_colors * bpc;

        of_property_read_u32(node, "xlnx,max-pclock-frequency",
                             &config->max_pclock);

        return 0;
}

static int xilinx_drm_dp_probe(struct platform_device *pdev)
{
        struct xilinx_drm_dp *dp;
        struct resource *res;
        u32 version, i;
        int irq, ret;

        dp = devm_kzalloc(&pdev->dev, sizeof(*dp), GFP_KERNEL);
        if (!dp)
                return -ENOMEM;

        dp->dpms = DRM_MODE_DPMS_OFF;
        dp->dev = &pdev->dev;

        ret = xilinx_drm_dp_parse_of(dp);
        if (ret < 0)
                return ret;

        dp->aclk = devm_clk_get(dp->dev, "aclk");
        if (IS_ERR(dp->aclk))
                return PTR_ERR(dp->aclk);

        ret = clk_prepare_enable(dp->aclk);
        if (ret) {
                dev_err(dp->dev, "failed to enable the aclk\n");
                return ret;
        }

        dp->aud_clk = devm_clk_get(dp->dev, "aud_clk");
        if (IS_ERR(dp->aud_clk)) {
                ret = PTR_ERR(dp->aud_clk);
                if (ret == -EPROBE_DEFER)
                        goto error_aclk;
                dp->aud_clk = NULL;
                dev_dbg(dp->dev, "failed to get the aud_clk:\n");
        } else {
                ret = clk_prepare_enable(dp->aud_clk);
                if (ret) {
                        dev_err(dp->dev, "failed to enable aud_clk\n");
                        goto error_aclk;
                }
        }

        dp->dp_sub = xilinx_drm_dp_sub_of_get(pdev->dev.of_node);
        if (IS_ERR(dp->dp_sub)) {
                ret = PTR_ERR(dp->dp_sub);
                goto error_aud_clk;
        }

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        dp->iomem = devm_ioremap_resource(dp->dev, res);
        if (IS_ERR(dp->iomem)) {
                ret = PTR_ERR(dp->iomem);
                goto error_dp_sub;
        }

        platform_set_drvdata(pdev, dp);

        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_PHY_POWER_DOWN,
                          XILINX_DP_TX_PHY_POWER_DOWN_ALL);
        xilinx_drm_set(dp->iomem, XILINX_DP_TX_PHY_CONFIG,
                       XILINX_DP_TX_PHY_CONFIG_ALL_RESET);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_FORCE_SCRAMBLER_RESET, 1);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_ENABLE, 0);

        if (dp->dp_sub) {
                for (i = 0; i < dp->config.max_lanes; i++) {
                        char phy_name[16];

                        snprintf(phy_name, sizeof(phy_name), "dp-phy%d", i);
                        dp->phy[i] = devm_phy_get(dp->dev, phy_name);
                        if (IS_ERR(dp->phy[i])) {
                                dev_err(dp->dev, "failed to get phy lane\n");
                                ret = PTR_ERR(dp->phy[i]);
                                dp->phy[i] = NULL;
                                goto error_dp_sub;
                        }
                }
        }

        ret = xilinx_drm_dp_init_phy(dp);
        if (ret)
                goto error_phy;

        dp->aux.name = "Xilinx DP AUX";
        dp->aux.dev = dp->dev;
        dp->aux.transfer = xilinx_drm_dp_aux_transfer;
        ret = drm_dp_aux_register(&dp->aux);
        if (ret < 0) {
                dev_err(dp->dev, "failed to initialize DP aux\n");
                goto error;
        }

        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                ret = irq;
                goto error;
        }

        ret = devm_request_threaded_irq(dp->dev, irq, NULL,
                                        xilinx_drm_dp_irq_handler, IRQF_ONESHOT,
                                        dev_name(dp->dev), dp);
        if (ret < 0)
                goto error;

        version = xilinx_drm_readl(dp->iomem, XILINX_DP_TX_VERSION);

        dev_info(dp->dev, "device found, version %u.%02x%x\n",
                 ((version & XILINX_DP_TX_VERSION_MAJOR_MASK) >>
                  XILINX_DP_TX_VERSION_MAJOR_SHIFT),
                 ((version & XILINX_DP_TX_VERSION_MINOR_MASK) >>
                  XILINX_DP_TX_VERSION_MINOR_SHIFT),
                 ((version & XILINX_DP_TX_VERSION_REVISION_MASK) >>
                  XILINX_DP_TX_VERSION_REVISION_SHIFT));

        version = xilinx_drm_readl(dp->iomem, XILINX_DP_TX_CORE_ID);
        if (version & XILINX_DP_TX_CORE_ID_DIRECTION) {
                dev_err(dp->dev, "Receiver is not supported\n");
                ret = -ENODEV;
                goto error;
        }

        dev_info(dp->dev, "Display Port, version %u.%02x%02x (tx)\n",
                 ((version & XILINX_DP_TX_CORE_ID_MAJOR_MASK) >>
                  XILINX_DP_TX_CORE_ID_MAJOR_SHIFT),
                 ((version & XILINX_DP_TX_CORE_ID_MINOR_MASK) >>
                  XILINX_DP_TX_CORE_ID_MINOR_SHIFT),
                 ((version & XILINX_DP_TX_CORE_ID_REVISION_MASK) >>
                  XILINX_DP_TX_CORE_ID_REVISION_SHIFT));

        pm_runtime_enable(dp->dev);

        return 0;

error:
        drm_dp_aux_unregister(&dp->aux);
error_dp_sub:
        xilinx_drm_dp_sub_put(dp->dp_sub);
error_phy:
        xilinx_drm_dp_exit_phy(dp);
error_aud_clk:
        if (dp->aud_clk)
                clk_disable_unprepare(dp->aud_clk);
error_aclk:
        clk_disable_unprepare(dp->aclk);
        return ret;
}

static int xilinx_drm_dp_remove(struct platform_device *pdev)
{
        struct xilinx_drm_dp *dp = platform_get_drvdata(pdev);

        pm_runtime_disable(dp->dev);
        xilinx_drm_writel(dp->iomem, XILINX_DP_TX_ENABLE, 0);

        drm_dp_aux_unregister(&dp->aux);
        xilinx_drm_dp_exit_phy(dp);
        xilinx_drm_dp_sub_put(dp->dp_sub);

        if (dp->aud_clk)
                clk_disable_unprepare(dp->aud_clk);
        clk_disable_unprepare(dp->aclk);

        return 0;
}

static const struct of_device_id xilinx_drm_dp_of_match[] = {
        { .compatible = "xlnx,v-dp", },
        { /* end of table */ },
};
MODULE_DEVICE_TABLE(of, xilinx_drm_dp_of_match);

static struct drm_platform_encoder_driver xilinx_drm_dp_driver = {
        .platform_driver = {
                .probe                  = xilinx_drm_dp_probe,
                .remove                 = xilinx_drm_dp_remove,
                .driver                 = {
                        .owner          = THIS_MODULE,
                        .name           = "xilinx-drm-dp",
                        .of_match_table = xilinx_drm_dp_of_match,
                },
        },

        .encoder_init = xilinx_drm_dp_encoder_init,
};

static int __init xilinx_drm_dp_init(void)
{
        return platform_driver_register(&xilinx_drm_dp_driver.platform_driver);
}

static void __exit xilinx_drm_dp_exit(void)
{
        platform_driver_unregister(&xilinx_drm_dp_driver.platform_driver);
}

module_init(xilinx_drm_dp_init);
module_exit(xilinx_drm_dp_exit);

MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Xilinx DRM KMS DiplayPort Driver");
MODULE_LICENSE("GPL v2");