// SPDX-License-Identifier: GPL-2.0
/*
 * ZynqMP DisplayPort Driver
 *
 * Copyright (C) 2017 - 2020 Xilinx, Inc.
 *
 * Authors:
 * - Hyun Woo Kwon <hyun.kwon@xilinx.com>
 * - Laurent Pinchart <laurent.pinchart@ideasonboard.com>
 */

#include <drm/drm_atomic_helper.h>
#include <drm/drm_connector.h>
#include <drm/drm_crtc.h>
#include <drm/drm_device.h>
#include <drm/drm_dp_helper.h>
#include <drm/drm_edid.h>
#include <drm/drm_encoder.h>
#include <drm/drm_managed.h>
#include <drm/drm_modes.h>
#include <drm/drm_of.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_simple_kms_helper.h>

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/phy/phy.h>
#include <linux/reset.h>

#include "zynqmp_disp.h"
#include "zynqmp_dp.h"
#include "zynqmp_dpsub.h"

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

/*
 * Some sink requires a delay after power on request
 */
static uint zynqmp_dp_power_on_delay_ms = 4;
module_param_named(power_on_delay_ms, zynqmp_dp_power_on_delay_ms, uint, 0444);
MODULE_PARM_DESC(power_on_delay_ms, "DP power on delay in msec (default: 4)");

/* Link configuration registers */
#define ZYNQMP_DP_LINK_BW_SET                           0x0
#define ZYNQMP_DP_LANE_COUNT_SET                        0x4
#define ZYNQMP_DP_ENHANCED_FRAME_EN                     0x8
#define ZYNQMP_DP_TRAINING_PATTERN_SET                  0xc
#define ZYNQMP_DP_SCRAMBLING_DISABLE                    0x14
#define ZYNQMP_DP_DOWNSPREAD_CTL                        0x18
#define ZYNQMP_DP_SOFTWARE_RESET                        0x1c
#define ZYNQMP_DP_SOFTWARE_RESET_STREAM1                BIT(0)
#define ZYNQMP_DP_SOFTWARE_RESET_STREAM2                BIT(1)
#define ZYNQMP_DP_SOFTWARE_RESET_STREAM3                BIT(2)
#define ZYNQMP_DP_SOFTWARE_RESET_STREAM4                BIT(3)
#define ZYNQMP_DP_SOFTWARE_RESET_AUX                    BIT(7)
#define ZYNQMP_DP_SOFTWARE_RESET_ALL                    (ZYNQMP_DP_SOFTWARE_RESET_STREAM1 | \
                                                         ZYNQMP_DP_SOFTWARE_RESET_STREAM2 | \
                                                         ZYNQMP_DP_SOFTWARE_RESET_STREAM3 | \
                                                         ZYNQMP_DP_SOFTWARE_RESET_STREAM4 | \
                                                         ZYNQMP_DP_SOFTWARE_RESET_AUX)

/* Core enable registers */
#define ZYNQMP_DP_TRANSMITTER_ENABLE                    0x80
#define ZYNQMP_DP_MAIN_STREAM_ENABLE                    0x84
#define ZYNQMP_DP_FORCE_SCRAMBLER_RESET                 0xc0
#define ZYNQMP_DP_VERSION                               0xf8
#define ZYNQMP_DP_VERSION_MAJOR_MASK                    GENMASK(31, 24)
#define ZYNQMP_DP_VERSION_MAJOR_SHIFT                   24
#define ZYNQMP_DP_VERSION_MINOR_MASK                    GENMASK(23, 16)
#define ZYNQMP_DP_VERSION_MINOR_SHIFT                   16
#define ZYNQMP_DP_VERSION_REVISION_MASK                 GENMASK(15, 12)
#define ZYNQMP_DP_VERSION_REVISION_SHIFT                12
#define ZYNQMP_DP_VERSION_PATCH_MASK                    GENMASK(11, 8)
#define ZYNQMP_DP_VERSION_PATCH_SHIFT                   8
#define ZYNQMP_DP_VERSION_INTERNAL_MASK                 GENMASK(7, 0)
#define ZYNQMP_DP_VERSION_INTERNAL_SHIFT                0

/* Core ID registers */
#define ZYNQMP_DP_CORE_ID                               0xfc
#define ZYNQMP_DP_CORE_ID_MAJOR_MASK                    GENMASK(31, 24)
#define ZYNQMP_DP_CORE_ID_MAJOR_SHIFT                   24
#define ZYNQMP_DP_CORE_ID_MINOR_MASK                    GENMASK(23, 16)
#define ZYNQMP_DP_CORE_ID_MINOR_SHIFT                   16
#define ZYNQMP_DP_CORE_ID_REVISION_MASK                 GENMASK(15, 8)
#define ZYNQMP_DP_CORE_ID_REVISION_SHIFT                8
#define ZYNQMP_DP_CORE_ID_DIRECTION                     GENMASK(1)

/* AUX channel interface registers */
#define ZYNQMP_DP_AUX_COMMAND                           0x100
#define ZYNQMP_DP_AUX_COMMAND_CMD_SHIFT                 8
#define ZYNQMP_DP_AUX_COMMAND_ADDRESS_ONLY              BIT(12)
#define ZYNQMP_DP_AUX_COMMAND_BYTES_SHIFT               0
#define ZYNQMP_DP_AUX_WRITE_FIFO                        0x104
#define ZYNQMP_DP_AUX_ADDRESS                           0x108
#define ZYNQMP_DP_AUX_CLK_DIVIDER                       0x10c
#define ZYNQMP_DP_AUX_CLK_DIVIDER_AUX_FILTER_SHIFT      8
#define ZYNQMP_DP_INTERRUPT_SIGNAL_STATE                0x130
#define ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_HPD            BIT(0)
#define ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REQUEST        BIT(1)
#define ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY          BIT(2)
#define ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY_TIMEOUT  BIT(3)
#define ZYNQMP_DP_AUX_REPLY_DATA                        0x134
#define ZYNQMP_DP_AUX_REPLY_CODE                        0x138
#define ZYNQMP_DP_AUX_REPLY_CODE_AUX_ACK                (0)
#define ZYNQMP_DP_AUX_REPLY_CODE_AUX_NACK               BIT(0)
#define ZYNQMP_DP_AUX_REPLY_CODE_AUX_DEFER              BIT(1)
#define ZYNQMP_DP_AUX_REPLY_CODE_I2C_ACK                (0)
#define ZYNQMP_DP_AUX_REPLY_CODE_I2C_NACK               BIT(2)
#define ZYNQMP_DP_AUX_REPLY_CODE_I2C_DEFER              BIT(3)
#define ZYNQMP_DP_AUX_REPLY_COUNT                       0x13c
#define ZYNQMP_DP_REPLY_DATA_COUNT                      0x148
#define ZYNQMP_DP_REPLY_DATA_COUNT_MASK                 0xff
#define ZYNQMP_DP_INT_STATUS                            0x3a0
#define ZYNQMP_DP_INT_MASK                              0x3a4
#define ZYNQMP_DP_INT_EN                                0x3a8
#define ZYNQMP_DP_INT_DS                                0x3ac
#define ZYNQMP_DP_INT_HPD_IRQ                           BIT(0)
#define ZYNQMP_DP_INT_HPD_EVENT                         BIT(1)
#define ZYNQMP_DP_INT_REPLY_RECEIVED                    BIT(2)
#define ZYNQMP_DP_INT_REPLY_TIMEOUT                     BIT(3)
#define ZYNQMP_DP_INT_HPD_PULSE_DET                     BIT(4)
#define ZYNQMP_DP_INT_EXT_PKT_TXD                       BIT(5)
#define ZYNQMP_DP_INT_LIV_ABUF_UNDRFLW                  BIT(12)
#define ZYNQMP_DP_INT_VBLANK_START                      BIT(13)
#define ZYNQMP_DP_INT_PIXEL1_MATCH                      BIT(14)
#define ZYNQMP_DP_INT_PIXEL0_MATCH                      BIT(15)
#define ZYNQMP_DP_INT_CHBUF_UNDERFLW_MASK               0x3f0000
#define ZYNQMP_DP_INT_CHBUF_OVERFLW_MASK                0xfc00000
#define ZYNQMP_DP_INT_CUST_TS_2                         BIT(28)
#define ZYNQMP_DP_INT_CUST_TS                           BIT(29)
#define ZYNQMP_DP_INT_EXT_VSYNC_TS                      BIT(30)
#define ZYNQMP_DP_INT_VSYNC_TS                          BIT(31)
#define ZYNQMP_DP_INT_ALL                               (ZYNQMP_DP_INT_HPD_IRQ | \
                                                         ZYNQMP_DP_INT_HPD_EVENT | \
                                                         ZYNQMP_DP_INT_CHBUF_UNDERFLW_MASK | \
                                                         ZYNQMP_DP_INT_CHBUF_OVERFLW_MASK)

/* Main stream attribute registers */
#define ZYNQMP_DP_MAIN_STREAM_HTOTAL                    0x180
#define ZYNQMP_DP_MAIN_STREAM_VTOTAL                    0x184
#define ZYNQMP_DP_MAIN_STREAM_POLARITY                  0x188
#define ZYNQMP_DP_MAIN_STREAM_POLARITY_HSYNC_SHIFT      0
#define ZYNQMP_DP_MAIN_STREAM_POLARITY_VSYNC_SHIFT      1
#define ZYNQMP_DP_MAIN_STREAM_HSWIDTH                   0x18c
#define ZYNQMP_DP_MAIN_STREAM_VSWIDTH                   0x190
#define ZYNQMP_DP_MAIN_STREAM_HRES                      0x194
#define ZYNQMP_DP_MAIN_STREAM_VRES                      0x198
#define ZYNQMP_DP_MAIN_STREAM_HSTART                    0x19c
#define ZYNQMP_DP_MAIN_STREAM_VSTART                    0x1a0
#define ZYNQMP_DP_MAIN_STREAM_MISC0                     0x1a4
#define ZYNQMP_DP_MAIN_STREAM_MISC0_SYNC_LOCK           BIT(0)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_RGB     (0 << 1)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_YCRCB_422       (5 << 1)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_YCRCB_444       (6 << 1)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_MASK    (7 << 1)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_DYNAMIC_RANGE       BIT(3)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_YCBCR_COLR          BIT(4)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_6               (0 << 5)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_8               (1 << 5)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_10              (2 << 5)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_12              (3 << 5)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_16              (4 << 5)
#define ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_MASK            (7 << 5)
#define ZYNQMP_DP_MAIN_STREAM_MISC1                     0x1a8
#define ZYNQMP_DP_MAIN_STREAM_MISC1_Y_ONLY_EN           BIT(7)
#define ZYNQMP_DP_MAIN_STREAM_M_VID                     0x1ac
#define ZYNQMP_DP_MSA_TRANSFER_UNIT_SIZE                0x1b0
#define ZYNQMP_DP_MSA_TRANSFER_UNIT_SIZE_TU_SIZE_DEF    64
#define ZYNQMP_DP_MAIN_STREAM_N_VID                     0x1b4
#define ZYNQMP_DP_USER_PIX_WIDTH                        0x1b8
#define ZYNQMP_DP_USER_DATA_COUNT_PER_LANE              0x1bc
#define ZYNQMP_DP_MIN_BYTES_PER_TU                      0x1c4
#define ZYNQMP_DP_FRAC_BYTES_PER_TU                     0x1c8
#define ZYNQMP_DP_INIT_WAIT                             0x1cc

/* PHY configuration and status registers */
#define ZYNQMP_DP_PHY_RESET                             0x200
#define ZYNQMP_DP_PHY_RESET_PHY_RESET                   BIT(0)
#define ZYNQMP_DP_PHY_RESET_GTTX_RESET                  BIT(1)
#define ZYNQMP_DP_PHY_RESET_PHY_PMA_RESET               BIT(8)
#define ZYNQMP_DP_PHY_RESET_PHY_PCS_RESET               BIT(9)
#define ZYNQMP_DP_PHY_RESET_ALL_RESET                   (ZYNQMP_DP_PHY_RESET_PHY_RESET | \
                                                         ZYNQMP_DP_PHY_RESET_GTTX_RESET | \
                                                         ZYNQMP_DP_PHY_RESET_PHY_PMA_RESET | \
                                                         ZYNQMP_DP_PHY_RESET_PHY_PCS_RESET)
#define ZYNQMP_DP_PHY_PREEMPHASIS_LANE_0                0x210
#define ZYNQMP_DP_PHY_PREEMPHASIS_LANE_1                0x214
#define ZYNQMP_DP_PHY_PREEMPHASIS_LANE_2                0x218
#define ZYNQMP_DP_PHY_PREEMPHASIS_LANE_3                0x21c
#define ZYNQMP_DP_PHY_VOLTAGE_DIFF_LANE_0               0x220
#define ZYNQMP_DP_PHY_VOLTAGE_DIFF_LANE_1               0x224
#define ZYNQMP_DP_PHY_VOLTAGE_DIFF_LANE_2               0x228
#define ZYNQMP_DP_PHY_VOLTAGE_DIFF_LANE_3               0x22c
#define ZYNQMP_DP_PHY_CLOCK_SELECT                      0x234
#define ZYNQMP_DP_PHY_CLOCK_SELECT_1_62G                0x1
#define ZYNQMP_DP_PHY_CLOCK_SELECT_2_70G                0x3
#define ZYNQMP_DP_PHY_CLOCK_SELECT_5_40G                0x5
#define ZYNQMP_DP_TX_PHY_POWER_DOWN                     0x238
#define ZYNQMP_DP_TX_PHY_POWER_DOWN_LANE_0              BIT(0)
#define ZYNQMP_DP_TX_PHY_POWER_DOWN_LANE_1              BIT(1)
#define ZYNQMP_DP_TX_PHY_POWER_DOWN_LANE_2              BIT(2)
#define ZYNQMP_DP_TX_PHY_POWER_DOWN_LANE_3              BIT(3)
#define ZYNQMP_DP_TX_PHY_POWER_DOWN_ALL                 0xf
#define ZYNQMP_DP_PHY_PRECURSOR_LANE_0                  0x23c
#define ZYNQMP_DP_PHY_PRECURSOR_LANE_1                  0x240
#define ZYNQMP_DP_PHY_PRECURSOR_LANE_2                  0x244
#define ZYNQMP_DP_PHY_PRECURSOR_LANE_3                  0x248
#define ZYNQMP_DP_PHY_POSTCURSOR_LANE_0                 0x24c
#define ZYNQMP_DP_PHY_POSTCURSOR_LANE_1                 0x250
#define ZYNQMP_DP_PHY_POSTCURSOR_LANE_2                 0x254
#define ZYNQMP_DP_PHY_POSTCURSOR_LANE_3                 0x258
#define ZYNQMP_DP_SUB_TX_PHY_PRECURSOR_LANE_0           0x24c
#define ZYNQMP_DP_SUB_TX_PHY_PRECURSOR_LANE_1           0x250
#define ZYNQMP_DP_PHY_STATUS                            0x280
#define ZYNQMP_DP_PHY_STATUS_PLL_LOCKED_SHIFT           4
#define ZYNQMP_DP_PHY_STATUS_FPGA_PLL_LOCKED            BIT(6)

/* Audio registers */
#define ZYNQMP_DP_TX_AUDIO_CONTROL                      0x300
#define ZYNQMP_DP_TX_AUDIO_CHANNELS                     0x304
#define ZYNQMP_DP_TX_AUDIO_INFO_DATA                    0x308
#define ZYNQMP_DP_TX_M_AUD                              0x328
#define ZYNQMP_DP_TX_N_AUD                              0x32c
#define ZYNQMP_DP_TX_AUDIO_EXT_DATA                     0x330

#define ZYNQMP_DP_MAX_LANES                             2
#define ZYNQMP_MAX_FREQ                                 3000000

#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_V1_2                                         0x12

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

/**
 * struct zynqmp_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
 * @fmt: format identifier string
 */
struct zynqmp_dp_mode {
        u8 bw_code;
        u8 lane_cnt;
        int pclock;
        const char *fmt;
};

/**
 * struct zynqmp_dp_config - Configuration of DisplayPort from DTS
 * @misc0: misc0 configuration (per DP v1.2 spec)
 * @misc1: misc1 configuration (per DP v1.2 spec)
 * @bpp: bits per pixel
 */
struct zynqmp_dp_config {
        u8 misc0;
        u8 misc1;
        u8 bpp;
};

/**
 * struct zynqmp_dp - Xilinx DisplayPort core
 * @encoder: the drm encoder structure
 * @connector: the drm connector structure
 * @dev: device structure
 * @dpsub: Display subsystem
 * @drm: DRM core
 * @iomem: device I/O memory for register access
 * @reset: reset controller
 * @irq: irq
 * @config: IP core configuration from DTS
 * @aux: aux channel
 * @phy: PHY handles for DP lanes
 * @num_lanes: number of enabled phy lanes
 * @hpd_work: hot plug detection worker
 * @status: connection status
 * @enabled: flag to indicate if the device is enabled
 * @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
 */
struct zynqmp_dp {
        struct drm_encoder encoder;
        struct drm_connector connector;
        struct device *dev;
        struct zynqmp_dpsub *dpsub;
        struct drm_device *drm;
        void __iomem *iomem;
        struct reset_control *reset;
        int irq;

        struct zynqmp_dp_config config;
        struct drm_dp_aux aux;
        struct phy *phy[ZYNQMP_DP_MAX_LANES];
        u8 num_lanes;
        struct delayed_work hpd_work;
        enum drm_connector_status status;
        bool enabled;

        u8 dpcd[DP_RECEIVER_CAP_SIZE];
        struct zynqmp_dp_link_config link_config;
        struct zynqmp_dp_mode mode;
        u8 train_set[ZYNQMP_DP_MAX_LANES];
};

static inline struct zynqmp_dp *encoder_to_dp(struct drm_encoder *encoder)
{
        return container_of(encoder, struct zynqmp_dp, encoder);
}

static inline struct zynqmp_dp *connector_to_dp(struct drm_connector *connector)
{
        return container_of(connector, struct zynqmp_dp, connector);
}

static void zynqmp_dp_write(struct zynqmp_dp *dp, int offset, u32 val)
{
        writel(val, dp->iomem + offset);
}

static u32 zynqmp_dp_read(struct zynqmp_dp *dp, int offset)
{
        return readl(dp->iomem + offset);
}

static void zynqmp_dp_clr(struct zynqmp_dp *dp, int offset, u32 clr)
{
        zynqmp_dp_write(dp, offset, zynqmp_dp_read(dp, offset) & ~clr);
}

static void zynqmp_dp_set(struct zynqmp_dp *dp, int offset, u32 set)
{
        zynqmp_dp_write(dp, offset, zynqmp_dp_read(dp, offset) | set);
}

/* -----------------------------------------------------------------------------
 * PHY Handling
 */

#define RST_TIMEOUT_MS                  1000

static int zynqmp_dp_reset(struct zynqmp_dp *dp, bool assert)
{
        unsigned long timeout;

        if (assert)
                reset_control_assert(dp->reset);
        else
                reset_control_deassert(dp->reset);

        /* Wait for the (de)assert to complete. */
        timeout = jiffies + msecs_to_jiffies(RST_TIMEOUT_MS);
        while (!time_after_eq(jiffies, timeout)) {
                bool status = !!reset_control_status(dp->reset);

                if (assert == status)
                        return 0;

                cpu_relax();
        }

        dev_err(dp->dev, "reset %s timeout\n", assert ? "assert" : "deassert");
        return -ETIMEDOUT;
}

/**
 * zynqmp_dp_phy_init - 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 zynqmp_dp_phy_init(struct zynqmp_dp *dp)
{
        int ret;
        int i;

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

        zynqmp_dp_clr(dp, ZYNQMP_DP_PHY_RESET, ZYNQMP_DP_PHY_RESET_ALL_RESET);

        /*
         * Power on lanes in reverse order as only lane 0 waits for the PLL to
         * lock.
         */
        for (i = dp->num_lanes - 1; i >= 0; i--) {
                ret = phy_power_on(dp->phy[i]);
                if (ret) {
                        dev_err(dp->dev, "failed to power on phy lane %d\n", i);
                        return ret;
                }
        }

        return 0;
}

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

        for (i = 0; i < dp->num_lanes; i++) {
                ret = phy_power_off(dp->phy[i]);
                if (ret)
                        dev_err(dp->dev, "failed to power off phy(%d) %d\n", i,
                                ret);
        }

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

/**
 * zynqmp_dp_phy_probe - Probe the PHYs
 * @dp: DisplayPort IP core structure
 *
 * Probe PHYs for all lanes. Less PHYs may be available than the number of
 * lanes, which is not considered an error as long as at least one PHY is
 * found. The caller can check dp->num_lanes to check how many PHYs were found.
 *
 * Return:
 * * 0                          - Success
 * * -ENXIO                     - No PHY found
 * * -EPROBE_DEFER              - Probe deferral requested
 * * Other negative value       - PHY retrieval failure
 */
static int zynqmp_dp_phy_probe(struct zynqmp_dp *dp)
{
        unsigned int i;

        for (i = 0; i < ZYNQMP_DP_MAX_LANES; i++) {
                char phy_name[16];
                struct phy *phy;

                snprintf(phy_name, sizeof(phy_name), "dp-phy%d", i);
                phy = devm_phy_get(dp->dev, phy_name);

                if (IS_ERR(phy)) {
                        switch (PTR_ERR(phy)) {
                        case -ENODEV:
                                if (dp->num_lanes)
                                        return 0;

                                dev_err(dp->dev, "no PHY found\n");
                                return -ENXIO;

                        case -EPROBE_DEFER:
                                return -EPROBE_DEFER;

                        default:
                                dev_err(dp->dev, "failed to get PHY lane %u\n",
                                        i);
                                return PTR_ERR(phy);
                        }
                }

                dp->phy[i] = phy;
                dp->num_lanes++;
        }

        return 0;
}

/**
 * zynqmp_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 zynqmp_dp_phy_ready(struct zynqmp_dp *dp)
{
        u32 i, reg, ready;

        ready = (1 << dp->num_lanes) - 1;

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

                if (i == 100) {
                        dev_err(dp->dev, "PHY isn't ready\n");
                        return -ENODEV;
                }

                usleep_range(1000, 1100);
        }

        return 0;
}

/* -----------------------------------------------------------------------------
 * DisplayPort Link Training
 */

/**
 * zynqmp_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 zynqmp_dp_max_rate(int link_rate, u8 lane_num, u8 bpp)
{
        return link_rate * lane_num * 8 / bpp;
}

/**
 * zynqmp_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 zynqmp_dp_mode_configure(struct zynqmp_dp *dp, int pclock,
                                    u8 current_bw)
{
        int max_rate = dp->link_config.max_rate;
        u8 bw_code;
        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;

        /* Downshift from current bandwidth */
        switch (current_bw) {
        case DP_LINK_BW_5_4:
                bw_code = DP_LINK_BW_2_7;
                break;
        case DP_LINK_BW_2_7:
                bw_code = DP_LINK_BW_1_62;
                break;
        case DP_LINK_BW_1_62:
                dev_err(dp->dev, "can't downshift. already lowest link rate\n");
                return -EINVAL;
        default:
                /* If not given, start with max supported */
                bw_code = max_link_rate_code;
                break;
        }

        for (lane_cnt = 1; lane_cnt <= max_lanes; lane_cnt <<= 1) {
                int bw;
                u32 rate;

                bw = drm_dp_bw_code_to_link_rate(bw_code);
                rate = zynqmp_dp_max_rate(bw, lane_cnt, bpp);
                if (pclock <= rate) {
                        dp->mode.bw_code = bw_code;
                        dp->mode.lane_cnt = lane_cnt;
                        dp->mode.pclock = pclock;
                        return dp->mode.bw_code;
                }
        }

        dev_err(dp->dev, "failed to configure link values\n");

        return -EINVAL;
}

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

        if (preemphasis >= DP_TRAIN_PRE_EMPH_LEVEL_2)
                preemphasis |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;

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

/**
 * zynqmp_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 zynqmp_dp_update_vs_emph(struct zynqmp_dp *dp)
{
        unsigned int i;
        int ret;

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

        for (i = 0; i < dp->mode.lane_cnt; i++) {
                u32 reg = ZYNQMP_DP_SUB_TX_PHY_PRECURSOR_LANE_0 + i * 4;
                union phy_configure_opts opts = { 0 };
                u8 train = dp->train_set[i];

                opts.dp.voltage[0] = (train & DP_TRAIN_VOLTAGE_SWING_MASK)
                                   >> DP_TRAIN_VOLTAGE_SWING_SHIFT;
                opts.dp.pre[0] = (train & DP_TRAIN_PRE_EMPHASIS_MASK)
                               >> DP_TRAIN_PRE_EMPHASIS_SHIFT;

                phy_configure(dp->phy[i], &opts);

                zynqmp_dp_write(dp, reg, 0x2);
        }

        return 0;
}

/**
 * zynqmp_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 zynqmp_dp_link_train_cr(struct zynqmp_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;

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

        /*
         * 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 = zynqmp_dp_update_vs_emph(dp);
                if (ret)
                        return ret;

                drm_dp_link_train_clock_recovery_delay(&dp->aux, 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;
                zynqmp_dp_adjust_train(dp, link_status);
        }

        if (!cr_done)
                return -EIO;

        return 0;
}

/**
 * zynqmp_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 zynqmp_dp_link_train_ce(struct zynqmp_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->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;

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

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

                drm_dp_link_train_channel_eq_delay(&dp->aux, 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;

                zynqmp_dp_adjust_train(dp, link_status);
        }

        if (!ce_done)
                return -EIO;

        return 0;
}

/**
 * zynqmp_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 zynqmp_dp_train(struct zynqmp_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;

        zynqmp_dp_write(dp, ZYNQMP_DP_LANE_COUNT_SET, lane_cnt);
        enhanced = drm_dp_enhanced_frame_cap(dp->dpcd);
        if (enhanced) {
                zynqmp_dp_write(dp, ZYNQMP_DP_ENHANCED_FRAME_EN, 1);
                aux_lane_cnt |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
        }

        if (dp->dpcd[3] & 0x1) {
                zynqmp_dp_write(dp, ZYNQMP_DP_DOWNSPREAD_CTL, 1);
                drm_dp_dpcd_writeb(&dp->aux, DP_DOWNSPREAD_CTRL,
                                   DP_SPREAD_AMP_0_5);
        } else {
                zynqmp_dp_write(dp, ZYNQMP_DP_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) {
                dev_err(dp->dev, "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) {
                dev_err(dp->dev, "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) {
                dev_err(dp->dev, "failed to set DP bandwidth\n");
                return ret;
        }

        zynqmp_dp_write(dp, ZYNQMP_DP_LINK_BW_SET, bw_code);
        switch (bw_code) {
        case DP_LINK_BW_1_62:
                reg = ZYNQMP_DP_PHY_CLOCK_SELECT_1_62G;
                break;
        case DP_LINK_BW_2_7:
                reg = ZYNQMP_DP_PHY_CLOCK_SELECT_2_70G;
                break;
        case DP_LINK_BW_5_4:
        default:
                reg = ZYNQMP_DP_PHY_CLOCK_SELECT_5_40G;
                break;
        }

        zynqmp_dp_write(dp, ZYNQMP_DP_PHY_CLOCK_SELECT, reg);
        ret = zynqmp_dp_phy_ready(dp);
        if (ret < 0)
                return ret;

        zynqmp_dp_write(dp, ZYNQMP_DP_SCRAMBLING_DISABLE, 1);
        memset(dp->train_set, 0, sizeof(dp->train_set));
        ret = zynqmp_dp_link_train_cr(dp);
        if (ret)
                return ret;

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

        ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
                                 DP_TRAINING_PATTERN_DISABLE);
        if (ret < 0) {
                dev_err(dp->dev, "failed to disable training pattern\n");
                return ret;
        }
        zynqmp_dp_write(dp, ZYNQMP_DP_TRAINING_PATTERN_SET,
                        DP_TRAINING_PATTERN_DISABLE);

        zynqmp_dp_write(dp, ZYNQMP_DP_SCRAMBLING_DISABLE, 0);

        return 0;
}

/**
 * zynqmp_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 zynqmp_dp_train_loop(struct zynqmp_dp *dp)
{
        struct zynqmp_dp_mode *mode = &dp->mode;
        u8 bw = mode->bw_code;
        int ret;

        do {
                if (dp->status == connector_status_disconnected ||
                    !dp->enabled)
                        return;

                ret = zynqmp_dp_train(dp);
                if (!ret)
                        return;

                ret = zynqmp_dp_mode_configure(dp, mode->pclock, bw);
                if (ret < 0)
                        goto err_out;

                bw = ret;
        } while (bw >= DP_LINK_BW_1_62);

err_out:
        dev_err(dp->dev, "failed to train the DP link\n");
}

/* -----------------------------------------------------------------------------
 * DisplayPort AUX
 */

#define AUX_READ_BIT    0x1

/**
 * zynqmp_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 zynqmp_dp_aux_cmd_submit(struct zynqmp_dp *dp, u32 cmd, u16 addr,
                                    u8 *buf, u8 bytes, u8 *reply)
{
        bool is_read = (cmd & AUX_READ_BIT) ? true : false;
        u32 reg, i;

        reg = zynqmp_dp_read(dp, ZYNQMP_DP_INTERRUPT_SIGNAL_STATE);
        if (reg & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REQUEST)
                return -EBUSY;

        zynqmp_dp_write(dp, ZYNQMP_DP_AUX_ADDRESS, addr);
        if (!is_read)
                for (i = 0; i < bytes; i++)
                        zynqmp_dp_write(dp, ZYNQMP_DP_AUX_WRITE_FIFO,
                                        buf[i]);

        reg = cmd << ZYNQMP_DP_AUX_COMMAND_CMD_SHIFT;
        if (!buf || !bytes)
                reg |= ZYNQMP_DP_AUX_COMMAND_ADDRESS_ONLY;
        else
                reg |= (bytes - 1) << ZYNQMP_DP_AUX_COMMAND_BYTES_SHIFT;
        zynqmp_dp_write(dp, ZYNQMP_DP_AUX_COMMAND, reg);

        /* Wait for reply to be delivered upto 2ms */
        for (i = 0; ; i++) {
                reg = zynqmp_dp_read(dp, ZYNQMP_DP_INTERRUPT_SIGNAL_STATE);
                if (reg & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_REPLY)
                        break;

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

                usleep_range(1000, 1100);
        }

        reg = zynqmp_dp_read(dp, ZYNQMP_DP_AUX_REPLY_CODE);
        if (reply)
                *reply = reg;

        if (is_read &&
            (reg == ZYNQMP_DP_AUX_REPLY_CODE_AUX_ACK ||
             reg == ZYNQMP_DP_AUX_REPLY_CODE_I2C_ACK)) {
                reg = zynqmp_dp_read(dp, ZYNQMP_DP_REPLY_DATA_COUNT);
                if ((reg & ZYNQMP_DP_REPLY_DATA_COUNT_MASK) != bytes)
                        return -EIO;

                for (i = 0; i < bytes; i++)
                        buf[i] = zynqmp_dp_read(dp, ZYNQMP_DP_AUX_REPLY_DATA);
        }

        return 0;
}

static ssize_t

zynqmp_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
{
        struct zynqmp_dp *dp = container_of(aux, struct zynqmp_dp, aux);
        int ret;
        unsigned int i, iter;

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

        for (i = 0; i < iter; i++) {
                ret = zynqmp_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;
                }

                if (dp->status == connector_status_disconnected) {
                        dev_dbg(dp->dev, "no connected aux device\n");
                        return -ENODEV;
                }

                usleep_range(400, 500);
        }

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

        return ret;
}

/**
 * zynqmp_dp_aux_init - Initialize and register the DP AUX
 * @dp: DisplayPort IP core structure
 *
 * Program the AUX clock divider and filter and register the DP AUX adapter.
 *
 * Return: 0 on success, error value otherwise
 */
static int zynqmp_dp_aux_init(struct zynqmp_dp *dp)
{
        unsigned long rate;
        unsigned int w;

        /*
         * The AUX_SIGNAL_WIDTH_FILTER is the number of APB clock cycles
         * corresponding to the AUX pulse. Allowable values are 8, 16, 24, 32,
         * 40 and 48. The AUX pulse width must be between 0.4µs and 0.6µs,
         * compute the w / 8 value corresponding to 0.4µs rounded up, and make
         * sure it stays below 0.6µs and within the allowable values.
         */
        rate = clk_get_rate(dp->dpsub->apb_clk);
        w = DIV_ROUND_UP(4 * rate, 1000 * 1000 * 10 * 8) * 8;
        if (w > 6 * rate / (1000 * 1000 * 10) || w > 48) {
                dev_err(dp->dev, "aclk frequency too high\n");
                return -EINVAL;
        }

        zynqmp_dp_write(dp, ZYNQMP_DP_AUX_CLK_DIVIDER,
                        (w << ZYNQMP_DP_AUX_CLK_DIVIDER_AUX_FILTER_SHIFT) |
                        (rate / (1000 * 1000)));

        dp->aux.name = "ZynqMP DP AUX";
        dp->aux.dev = dp->dev;
        dp->aux.drm_dev = dp->drm;
        dp->aux.transfer = zynqmp_dp_aux_transfer;

        return drm_dp_aux_register(&dp->aux);
}

/**
 * zynqmp_dp_aux_cleanup - Cleanup the DP AUX
 * @dp: DisplayPort IP core structure
 *
 * Unregister the DP AUX adapter.
 */
static void zynqmp_dp_aux_cleanup(struct zynqmp_dp *dp)
{
        drm_dp_aux_unregister(&dp->aux);
}

/* -----------------------------------------------------------------------------
 * DisplayPort Generic Support
 */

/**
 * zynqmp_dp_update_misc - Write the misc registers
 * @dp: DisplayPort IP core structure
 *
 * The misc register values are stored in the structure, and this
 * function applies the values into the registers.
 */
static void zynqmp_dp_update_misc(struct zynqmp_dp *dp)
{
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_MISC0, dp->config.misc0);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_MISC1, dp->config.misc1);
}

/**
 * zynqmp_dp_set_format - Set the input format
 * @dp: DisplayPort IP core structure
 * @format: input format
 * @bpc: bits per component
 *
 * Update misc register values based on input @format and @bpc.
 *
 * Return: 0 on success, or -EINVAL.
 */
static int zynqmp_dp_set_format(struct zynqmp_dp *dp,
                                enum zynqmp_dpsub_format format,
                                unsigned int bpc)
{
        static const struct drm_display_info *display;
        struct zynqmp_dp_config *config = &dp->config;
        unsigned int num_colors;

        config->misc0 &= ~ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_MASK;
        config->misc1 &= ~ZYNQMP_DP_MAIN_STREAM_MISC1_Y_ONLY_EN;

        switch (format) {
        case ZYNQMP_DPSUB_FORMAT_RGB:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_RGB;
                num_colors = 3;
                break;

        case ZYNQMP_DPSUB_FORMAT_YCRCB444:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_YCRCB_444;
                num_colors = 3;
                break;

        case ZYNQMP_DPSUB_FORMAT_YCRCB422:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_COMP_FORMAT_YCRCB_422;
                num_colors = 2;
                break;

        case ZYNQMP_DPSUB_FORMAT_YONLY:
                config->misc1 |= ZYNQMP_DP_MAIN_STREAM_MISC1_Y_ONLY_EN;
                num_colors = 1;
                break;

        default:
                dev_err(dp->dev, "Invalid colormetry in DT\n");
                return -EINVAL;
        }

        display = &dp->connector.display_info;
        if (display->bpc && bpc > display->bpc) {
                dev_warn(dp->dev,
                         "downgrading requested %ubpc to display limit %ubpc\n",
                         bpc, display->bpc);
                bpc = display->bpc;
        }

        config->misc0 &= ~ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_MASK;

        switch (bpc) {
        case 6:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_6;
                break;
        case 8:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_8;
                break;
        case 10:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_10;
                break;
        case 12:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_12;
                break;
        case 16:
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_16;
                break;
        default:
                dev_warn(dp->dev, "Not supported bpc (%u). fall back to 8bpc\n",
                         bpc);
                config->misc0 |= ZYNQMP_DP_MAIN_STREAM_MISC0_BPC_8;
                bpc = 8;
                break;
        }

        /* Update the current bpp based on the format. */
        config->bpp = bpc * num_colors;

        return 0;
}

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

        /* Use the max transfer unit size (default) */
        zynqmp_dp_write(dp, ZYNQMP_DP_MSA_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);
        zynqmp_dp_write(dp, ZYNQMP_DP_MIN_BYTES_PER_TU,
                        avg_bytes_per_tu / 1000);
        zynqmp_dp_write(dp, ZYNQMP_DP_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;

        zynqmp_dp_write(dp, ZYNQMP_DP_INIT_WAIT, init_wait);
}

/**
 * zynqmp_dp_encoder_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 zynqmp_dp_encoder_mode_set_stream(struct zynqmp_dp *dp,
                                              const struct drm_display_mode *mode)
{
        u8 lane_cnt = dp->mode.lane_cnt;
        u32 reg, wpl;
        unsigned int rate;

        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_HTOTAL, mode->htotal);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_VTOTAL, mode->vtotal);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_POLARITY,
                        (!!(mode->flags & DRM_MODE_FLAG_PVSYNC) <<
                         ZYNQMP_DP_MAIN_STREAM_POLARITY_VSYNC_SHIFT) |
                        (!!(mode->flags & DRM_MODE_FLAG_PHSYNC) <<
                         ZYNQMP_DP_MAIN_STREAM_POLARITY_HSYNC_SHIFT));
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_HSWIDTH,
                        mode->hsync_end - mode->hsync_start);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_VSWIDTH,
                        mode->vsync_end - mode->vsync_start);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_HRES, mode->hdisplay);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_VRES, mode->vdisplay);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_HSTART,
                        mode->htotal - mode->hsync_start);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_VSTART,
                        mode->vtotal - mode->vsync_start);

        /* In synchronous mode, set the diviers */
        if (dp->config.misc0 & ZYNQMP_DP_MAIN_STREAM_MISC0_SYNC_LOCK) {
                reg = drm_dp_bw_code_to_link_rate(dp->mode.bw_code);
                zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_N_VID, reg);
                zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_M_VID, mode->clock);
                rate = zynqmp_disp_get_audio_clk_rate(dp->dpsub->disp);
                if (rate) {
                        dev_dbg(dp->dev, "Audio rate: %d\n", rate / 512);
                        zynqmp_dp_write(dp, ZYNQMP_DP_TX_N_AUD, reg);
                        zynqmp_dp_write(dp, ZYNQMP_DP_TX_M_AUD, rate / 1000);
                }
        }

        /* Only 2 channel audio is supported now */
        if (zynqmp_disp_audio_enabled(dp->dpsub->disp))
                zynqmp_dp_write(dp, ZYNQMP_DP_TX_AUDIO_CHANNELS, 1);

        zynqmp_dp_write(dp, ZYNQMP_DP_USER_PIX_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;
        zynqmp_dp_write(dp, ZYNQMP_DP_USER_DATA_COUNT_PER_LANE, reg);
}

/* -----------------------------------------------------------------------------
 * DRM Connector
 */

static enum drm_connector_status
zynqmp_dp_connector_detect(struct drm_connector *connector, bool force)
{
        struct zynqmp_dp *dp = connector_to_dp(connector);
        struct zynqmp_dp_link_config *link_config = &dp->link_config;
        u32 state, i;
        int ret;

        /*
         * This is from heuristic. It takes some delay (ex, 100 ~ 500 msec) to
         * get the HPD signal with some monitors.
         */
        for (i = 0; i < 10; i++) {
                state = zynqmp_dp_read(dp, ZYNQMP_DP_INTERRUPT_SIGNAL_STATE);
                if (state & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_HPD)
                        break;
                msleep(100);
        }

        if (state & ZYNQMP_DP_INTERRUPT_SIGNAL_STATE_HPD) {
                ret = drm_dp_dpcd_read(&dp->aux, 0x0, dp->dpcd,
                                       sizeof(dp->dpcd));
                if (ret < 0) {
                        dev_dbg(dp->dev, "DPCD read failed");
                        goto disconnected;
                }

                link_config->max_rate = min_t(int,
                                              drm_dp_max_link_rate(dp->dpcd),
                                              DP_HIGH_BIT_RATE2);
                link_config->max_lanes = min_t(u8,
                                               drm_dp_max_lane_count(dp->dpcd),
                                               dp->num_lanes);

                dp->status = connector_status_connected;
                return connector_status_connected;
        }

disconnected:
        dp->status = connector_status_disconnected;
        return connector_status_disconnected;
}

static int zynqmp_dp_connector_get_modes(struct drm_connector *connector)
{
        struct zynqmp_dp *dp = connector_to_dp(connector);
        struct edid *edid;
        int ret;

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

        drm_connector_update_edid_property(connector, edid);
        ret = drm_add_edid_modes(connector, edid);
        kfree(edid);

        return ret;
}

static struct drm_encoder *
zynqmp_dp_connector_best_encoder(struct drm_connector *connector)
{
        struct zynqmp_dp *dp = connector_to_dp(connector);

        return &dp->encoder;
}

static int zynqmp_dp_connector_mode_valid(struct drm_connector *connector,
                                          struct drm_display_mode *mode)
{
        struct zynqmp_dp *dp = connector_to_dp(connector);
        u8 max_lanes = dp->link_config.max_lanes;
        u8 bpp = dp->config.bpp;
        int max_rate = dp->link_config.max_rate;
        int rate;

        if (mode->clock > ZYNQMP_MAX_FREQ) {
                dev_dbg(dp->dev, "filtered the mode, %s,for high pixel rate\n",
                        mode->name);
                drm_mode_debug_printmodeline(mode);
                return MODE_CLOCK_HIGH;
        }

        /* Check with link rate and lane count */
        rate = zynqmp_dp_max_rate(max_rate, max_lanes, bpp);
        if (mode->clock > rate) {
                dev_dbg(dp->dev, "filtered the mode, %s,for high pixel rate\n",
                        mode->name);
                drm_mode_debug_printmodeline(mode);
                return MODE_CLOCK_HIGH;
        }

        return MODE_OK;
}

static const struct drm_connector_funcs zynqmp_dp_connector_funcs = {
        .detect                 = zynqmp_dp_connector_detect,
        .fill_modes             = drm_helper_probe_single_connector_modes,
        .destroy                = drm_connector_cleanup,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
        .atomic_destroy_state   = drm_atomic_helper_connector_destroy_state,
        .reset                  = drm_atomic_helper_connector_reset,
};

static const struct drm_connector_helper_funcs
zynqmp_dp_connector_helper_funcs = {
        .get_modes      = zynqmp_dp_connector_get_modes,
        .best_encoder   = zynqmp_dp_connector_best_encoder,
        .mode_valid     = zynqmp_dp_connector_mode_valid,
};

/* -----------------------------------------------------------------------------
 * DRM Encoder
 */

static void zynqmp_dp_encoder_enable(struct drm_encoder *encoder)
{
        struct zynqmp_dp *dp = encoder_to_dp(encoder);
        unsigned int i;
        int ret = 0;

        pm_runtime_get_sync(dp->dev);
        dp->enabled = true;
        zynqmp_dp_update_misc(dp);
        if (zynqmp_disp_audio_enabled(dp->dpsub->disp))
                zynqmp_dp_write(dp, ZYNQMP_DP_TX_AUDIO_CONTROL, 1);
        zynqmp_dp_write(dp, ZYNQMP_DP_TX_PHY_POWER_DOWN, 0);
        if (dp->status == connector_status_connected) {
                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);
                }
                /* Some monitors take time to wake up properly */
                msleep(zynqmp_dp_power_on_delay_ms);
        }
        if (ret != 1)
                dev_dbg(dp->dev, "DP aux failed\n");
        else
                zynqmp_dp_train_loop(dp);
        zynqmp_dp_write(dp, ZYNQMP_DP_SOFTWARE_RESET,
                        ZYNQMP_DP_SOFTWARE_RESET_ALL);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_ENABLE, 1);
}

static void zynqmp_dp_encoder_disable(struct drm_encoder *encoder)
{
        struct zynqmp_dp *dp = encoder_to_dp(encoder);

        dp->enabled = false;
        cancel_delayed_work(&dp->hpd_work);
        zynqmp_dp_write(dp, ZYNQMP_DP_MAIN_STREAM_ENABLE, 0);
        drm_dp_dpcd_writeb(&dp->aux, DP_SET_POWER, DP_SET_POWER_D3);
        zynqmp_dp_write(dp, ZYNQMP_DP_TX_PHY_POWER_DOWN,
                        ZYNQMP_DP_TX_PHY_POWER_DOWN_ALL);
        if (zynqmp_disp_audio_enabled(dp->dpsub->disp))
                zynqmp_dp_write(dp, ZYNQMP_DP_TX_AUDIO_CONTROL, 0);
        pm_runtime_put_sync(dp->dev);
}

static void
zynqmp_dp_encoder_atomic_mode_set(struct drm_encoder *encoder,
                                  struct drm_crtc_state *crtc_state,
                                  struct drm_connector_state *connector_state)
{
        struct zynqmp_dp *dp = encoder_to_dp(encoder);
        struct drm_display_mode *mode = &crtc_state->mode;
        struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
        u8 max_lanes = dp->link_config.max_lanes;
        u8 bpp = dp->config.bpp;
        int rate, max_rate = dp->link_config.max_rate;
        int ret;

        zynqmp_dp_set_format(dp, ZYNQMP_DPSUB_FORMAT_RGB, 8);

        /* Check again as bpp or format might have been chagned */
        rate = zynqmp_dp_max_rate(max_rate, max_lanes, bpp);
        if (mode->clock > rate) {
                dev_err(dp->dev, "the mode, %s,has too high pixel rate\n",
                        mode->name);
                drm_mode_debug_printmodeline(mode);
        }

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

        zynqmp_dp_encoder_mode_set_transfer_unit(dp, adjusted_mode);
        zynqmp_dp_encoder_mode_set_stream(dp, adjusted_mode);
}

#define ZYNQMP_DP_MIN_H_BACKPORCH       20

static int
zynqmp_dp_encoder_atomic_check(struct drm_encoder *encoder,
                               struct drm_crtc_state *crtc_state,
                               struct drm_connector_state *conn_state)
{
        struct drm_display_mode *mode = &crtc_state->mode;
        struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
        int diff = mode->htotal - mode->hsync_end;

        /*
         * ZynqMP DP requires horizontal backporch to be greater than 12.
         * This limitation may not be compatible with the sink device.
         */
        if (diff < ZYNQMP_DP_MIN_H_BACKPORCH) {
                int vrefresh = (adjusted_mode->clock * 1000) /
                               (adjusted_mode->vtotal * adjusted_mode->htotal);

                dev_dbg(encoder->dev->dev, "hbackporch adjusted: %d to %d",
                        diff, ZYNQMP_DP_MIN_H_BACKPORCH - diff);
                diff = ZYNQMP_DP_MIN_H_BACKPORCH - diff;
                adjusted_mode->htotal += diff;
                adjusted_mode->clock = adjusted_mode->vtotal *
                                       adjusted_mode->htotal * vrefresh / 1000;
        }

        return 0;
}

static const struct drm_encoder_helper_funcs zynqmp_dp_encoder_helper_funcs = {
        .enable                 = zynqmp_dp_encoder_enable,
        .disable                = zynqmp_dp_encoder_disable,
        .atomic_mode_set        = zynqmp_dp_encoder_atomic_mode_set,
        .atomic_check           = zynqmp_dp_encoder_atomic_check,
};

/* -----------------------------------------------------------------------------
 * Interrupt Handling
 */

/**
 * zynqmp_dp_enable_vblank - Enable vblank
 * @dp: DisplayPort IP core structure
 *
 * Enable vblank interrupt
 */
void zynqmp_dp_enable_vblank(struct zynqmp_dp *dp)
{
        zynqmp_dp_write(dp, ZYNQMP_DP_INT_EN, ZYNQMP_DP_INT_VBLANK_START);
}

/**
 * zynqmp_dp_disable_vblank - Disable vblank
 * @dp: DisplayPort IP core structure
 *
 * Disable vblank interrupt
 */
void zynqmp_dp_disable_vblank(struct zynqmp_dp *dp)
{
        zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, ZYNQMP_DP_INT_VBLANK_START);
}

static void zynqmp_dp_hpd_work_func(struct work_struct *work)
{
        struct zynqmp_dp *dp;

        dp = container_of(work, struct zynqmp_dp, hpd_work.work);

        if (dp->drm)
                drm_helper_hpd_irq_event(dp->drm);
}

static irqreturn_t zynqmp_dp_irq_handler(int irq, void *data)
{
        struct zynqmp_dp *dp = (struct zynqmp_dp *)data;
        u32 status, mask;

        status = zynqmp_dp_read(dp, ZYNQMP_DP_INT_STATUS);
        mask = zynqmp_dp_read(dp, ZYNQMP_DP_INT_MASK);
        if (!(status & ~mask))
                return IRQ_NONE;

        /* dbg for diagnostic, but not much that the driver can do */
        if (status & ZYNQMP_DP_INT_CHBUF_UNDERFLW_MASK)
                dev_dbg_ratelimited(dp->dev, "underflow interrupt\n");
        if (status & ZYNQMP_DP_INT_CHBUF_OVERFLW_MASK)
                dev_dbg_ratelimited(dp->dev, "overflow interrupt\n");

        zynqmp_dp_write(dp, ZYNQMP_DP_INT_STATUS, status);

        if (status & ZYNQMP_DP_INT_VBLANK_START)
                zynqmp_disp_handle_vblank(dp->dpsub->disp);

        if (status & ZYNQMP_DP_INT_HPD_EVENT)
                schedule_delayed_work(&dp->hpd_work, 0);

        if (status & ZYNQMP_DP_INT_HPD_IRQ) {
                int ret;
                u8 status[DP_LINK_STATUS_SIZE + 2];

                ret = drm_dp_dpcd_read(&dp->aux, DP_SINK_COUNT, status,
                                       DP_LINK_STATUS_SIZE + 2);
                if (ret < 0)
                        goto handled;

                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)) {
                        zynqmp_dp_train_loop(dp);
                }
        }

handled:
        return IRQ_HANDLED;
}

/* -----------------------------------------------------------------------------
 * Initialization & Cleanup
 */

int zynqmp_dp_drm_init(struct zynqmp_dpsub *dpsub)
{
        struct zynqmp_dp *dp = dpsub->dp;
        struct drm_encoder *encoder = &dp->encoder;
        struct drm_connector *connector = &dp->connector;
        int ret;

        dp->config.misc0 &= ~ZYNQMP_DP_MAIN_STREAM_MISC0_SYNC_LOCK;
        zynqmp_dp_set_format(dp, ZYNQMP_DPSUB_FORMAT_RGB, 8);

        /* Create the DRM encoder and connector. */
        encoder->possible_crtcs |= zynqmp_disp_get_crtc_mask(dpsub->disp);
        drm_simple_encoder_init(dp->drm, encoder, DRM_MODE_ENCODER_TMDS);
        drm_encoder_helper_add(encoder, &zynqmp_dp_encoder_helper_funcs);

        connector->polled = DRM_CONNECTOR_POLL_HPD;
        ret = drm_connector_init(encoder->dev, connector,
                                 &zynqmp_dp_connector_funcs,
                                 DRM_MODE_CONNECTOR_DisplayPort);
        if (ret) {
                dev_err(dp->dev, "failed to create the DRM connector\n");
                return ret;
        }

        drm_connector_helper_add(connector, &zynqmp_dp_connector_helper_funcs);
        drm_connector_register(connector);
        drm_connector_attach_encoder(connector, encoder);

        /* Initialize and register the AUX adapter. */
        ret = zynqmp_dp_aux_init(dp);
        if (ret) {
                dev_err(dp->dev, "failed to initialize DP aux\n");
                return ret;
        }

        /* Now that initialisation is complete, enable interrupts. */
        zynqmp_dp_write(dp, ZYNQMP_DP_INT_EN, ZYNQMP_DP_INT_ALL);

        return 0;
}

int zynqmp_dp_probe(struct zynqmp_dpsub *dpsub, struct drm_device *drm)
{
        struct platform_device *pdev = to_platform_device(dpsub->dev);
        struct zynqmp_dp *dp;
        struct resource *res;
        int ret;

        dp = drmm_kzalloc(drm, sizeof(*dp), GFP_KERNEL);
        if (!dp)
                return -ENOMEM;

        dp->dev = &pdev->dev;
        dp->dpsub = dpsub;
        dp->status = connector_status_disconnected;
        dp->drm = drm;

        INIT_DELAYED_WORK(&dp->hpd_work, zynqmp_dp_hpd_work_func);

        dpsub->dp = dp;

        /* Acquire all resources (IOMEM, IRQ and PHYs). */
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dp");
        dp->iomem = devm_ioremap_resource(dp->dev, res);
        if (IS_ERR(dp->iomem))
                return PTR_ERR(dp->iomem);

        dp->irq = platform_get_irq(pdev, 0);
        if (dp->irq < 0)
                return dp->irq;

        dp->reset = devm_reset_control_get(dp->dev, NULL);
        if (IS_ERR(dp->reset)) {
                if (PTR_ERR(dp->reset) != -EPROBE_DEFER)
                        dev_err(dp->dev, "failed to get reset: %ld\n",
                                PTR_ERR(dp->reset));
                return PTR_ERR(dp->reset);
        }

        ret = zynqmp_dp_reset(dp, false);
        if (ret < 0)
                return ret;

        ret = zynqmp_dp_phy_probe(dp);
        if (ret)
                goto err_reset;

        /* Initialize the hardware. */
        zynqmp_dp_write(dp, ZYNQMP_DP_TX_PHY_POWER_DOWN,
                        ZYNQMP_DP_TX_PHY_POWER_DOWN_ALL);
        zynqmp_dp_set(dp, ZYNQMP_DP_PHY_RESET, ZYNQMP_DP_PHY_RESET_ALL_RESET);
        zynqmp_dp_write(dp, ZYNQMP_DP_FORCE_SCRAMBLER_RESET, 1);
        zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 0);
        zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, 0xffffffff);

        ret = zynqmp_dp_phy_init(dp);
        if (ret)
                goto err_reset;

        zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 1);

        /*
         * Now that the hardware is initialized and won't generate spurious
         * interrupts, request the IRQ.
         */
        ret = devm_request_threaded_irq(dp->dev, dp->irq, NULL,
                                        zynqmp_dp_irq_handler, IRQF_ONESHOT,
                                        dev_name(dp->dev), dp);
        if (ret < 0)
                goto err_phy_exit;

        dev_dbg(dp->dev, "ZynqMP DisplayPort Tx probed with %u lanes\n",
                dp->num_lanes);

        return 0;

err_phy_exit:
        zynqmp_dp_phy_exit(dp);
err_reset:
        zynqmp_dp_reset(dp, true);

        return ret;
}

void zynqmp_dp_remove(struct zynqmp_dpsub *dpsub)
{
        struct zynqmp_dp *dp = dpsub->dp;

        zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, ZYNQMP_DP_INT_ALL);
        disable_irq(dp->irq);

        cancel_delayed_work_sync(&dp->hpd_work);
        zynqmp_dp_aux_cleanup(dp);

        zynqmp_dp_write(dp, ZYNQMP_DP_TRANSMITTER_ENABLE, 0);
        zynqmp_dp_write(dp, ZYNQMP_DP_INT_DS, 0xffffffff);

        zynqmp_dp_phy_exit(dp);
        zynqmp_dp_reset(dp, true);
}