// SPDX-License-Identifier: GPL-2.0
/*
 * Cadence MHDP8546 DP bridge driver.
 *
 * Copyright (C) 2020 Cadence Design Systems, Inc.
 *
 */

#include <linux/io.h>
#include <linux/iopoll.h>

#include <linux/unaligned.h>

#include <drm/display/drm_hdcp_helper.h>

#include "cdns-mhdp8546-hdcp.h"

static int cdns_mhdp_secure_mailbox_read(struct cdns_mhdp_device *mhdp)
{
        int ret, empty;

        WARN_ON(!mutex_is_locked(&mhdp->mbox_mutex));

        ret = readx_poll_timeout(readl, mhdp->sapb_regs + CDNS_MAILBOX_EMPTY,
                                 empty, !empty, MAILBOX_RETRY_US,
                                 MAILBOX_TIMEOUT_US);
        if (ret < 0)
                return ret;

        return readl(mhdp->sapb_regs + CDNS_MAILBOX_RX_DATA) & 0xff;
}

static int cdns_mhdp_secure_mailbox_write(struct cdns_mhdp_device *mhdp,
                                          u8 val)
{
        int ret, full;

        WARN_ON(!mutex_is_locked(&mhdp->mbox_mutex));

        ret = readx_poll_timeout(readl, mhdp->sapb_regs + CDNS_MAILBOX_FULL,
                                 full, !full, MAILBOX_RETRY_US,
                                 MAILBOX_TIMEOUT_US);
        if (ret < 0)
                return ret;

        writel(val, mhdp->sapb_regs + CDNS_MAILBOX_TX_DATA);

        return 0;
}

static int cdns_mhdp_secure_mailbox_recv_header(struct cdns_mhdp_device *mhdp,
                                                u8 module_id,
                                                u8 opcode,
                                                u16 req_size)
{
        u32 mbox_size, i;
        u8 header[4];
        int ret;

        /* read the header of the message */
        for (i = 0; i < sizeof(header); i++) {
                ret = cdns_mhdp_secure_mailbox_read(mhdp);
                if (ret < 0)
                        return ret;

                header[i] = ret;
        }

        mbox_size = get_unaligned_be16(header + 2);

        if (opcode != header[0] || module_id != header[1] ||
            (opcode != HDCP_TRAN_IS_REC_ID_VALID && req_size != mbox_size)) {
                for (i = 0; i < mbox_size; i++)
                        if (cdns_mhdp_secure_mailbox_read(mhdp) < 0)
                                break;
                return -EINVAL;
        }

        return 0;
}

static int cdns_mhdp_secure_mailbox_recv_data(struct cdns_mhdp_device *mhdp,
                                              u8 *buff, u16 buff_size)
{
        int ret;
        u32 i;

        for (i = 0; i < buff_size; i++) {
                ret = cdns_mhdp_secure_mailbox_read(mhdp);
                if (ret < 0)
                        return ret;

                buff[i] = ret;
        }

        return 0;
}

static int cdns_mhdp_secure_mailbox_send(struct cdns_mhdp_device *mhdp,
                                         u8 module_id,
                                         u8 opcode,
                                         u16 size,
                                         u8 *message)
{
        u8 header[4];
        int ret;
        u32 i;

        header[0] = opcode;
        header[1] = module_id;
        put_unaligned_be16(size, header + 2);

        for (i = 0; i < sizeof(header); i++) {
                ret = cdns_mhdp_secure_mailbox_write(mhdp, header[i]);
                if (ret)
                        return ret;
        }

        for (i = 0; i < size; i++) {
                ret = cdns_mhdp_secure_mailbox_write(mhdp, message[i]);
                if (ret)
                        return ret;
        }

        return 0;
}

static int cdns_mhdp_hdcp_get_status(struct cdns_mhdp_device *mhdp,
                                     u16 *hdcp_port_status)
{
        u8 hdcp_status[HDCP_STATUS_SIZE];
        int ret;

        mutex_lock(&mhdp->mbox_mutex);
        ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
                                            HDCP_TRAN_STATUS_CHANGE, 0, NULL);
        if (ret)
                goto err_get_hdcp_status;

        ret = cdns_mhdp_secure_mailbox_recv_header(mhdp, MB_MODULE_ID_HDCP_TX,
                                                   HDCP_TRAN_STATUS_CHANGE,
                                                   sizeof(hdcp_status));
        if (ret)
                goto err_get_hdcp_status;

        ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, hdcp_status,
                                                 sizeof(hdcp_status));
        if (ret)
                goto err_get_hdcp_status;

        *hdcp_port_status = ((u16)(hdcp_status[0] << 8) | hdcp_status[1]);

err_get_hdcp_status:
        mutex_unlock(&mhdp->mbox_mutex);

        return ret;
}

static u8 cdns_mhdp_hdcp_handle_status(struct cdns_mhdp_device *mhdp,
                                       u16 status)
{
        u8 err = GET_HDCP_PORT_STS_LAST_ERR(status);

        if (err)
                dev_dbg(mhdp->dev, "HDCP Error = %d", err);

        return err;
}

static int cdns_mhdp_hdcp_rx_id_valid_response(struct cdns_mhdp_device *mhdp,
                                               u8 valid)
{
        int ret;

        mutex_lock(&mhdp->mbox_mutex);
        ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
                                            HDCP_TRAN_RESPOND_RECEIVER_ID_VALID,
                                            1, &valid);
        mutex_unlock(&mhdp->mbox_mutex);

        return ret;
}

static int cdns_mhdp_hdcp_rx_id_valid(struct cdns_mhdp_device *mhdp,
                                      u8 *recv_num, u8 *hdcp_rx_id)
{
        u8 rec_id_hdr[2];
        u8 status;
        int ret;

        mutex_lock(&mhdp->mbox_mutex);
        ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
                                            HDCP_TRAN_IS_REC_ID_VALID, 0, NULL);
        if (ret)
                goto err_rx_id_valid;

        ret = cdns_mhdp_secure_mailbox_recv_header(mhdp, MB_MODULE_ID_HDCP_TX,
                                                   HDCP_TRAN_IS_REC_ID_VALID,
                                                   sizeof(status));
        if (ret)
                goto err_rx_id_valid;

        ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, rec_id_hdr, 2);
        if (ret)
                goto err_rx_id_valid;

        *recv_num = rec_id_hdr[0];

        ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, hdcp_rx_id, 5 * *recv_num);

err_rx_id_valid:
        mutex_unlock(&mhdp->mbox_mutex);

        return ret;
}

static int cdns_mhdp_hdcp_km_stored_resp(struct cdns_mhdp_device *mhdp,
                                         u32 size, u8 *km)
{
        int ret;

        mutex_lock(&mhdp->mbox_mutex);
        ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
                                            HDCP2X_TX_RESPOND_KM, size, km);
        mutex_unlock(&mhdp->mbox_mutex);

        return ret;
}

static int cdns_mhdp_hdcp_tx_is_km_stored(struct cdns_mhdp_device *mhdp,
                                          u8 *resp, u32 size)
{
        int ret;

        mutex_lock(&mhdp->mbox_mutex);
        ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
                                            HDCP2X_TX_IS_KM_STORED, 0, NULL);
        if (ret)
                goto err_is_km_stored;

        ret = cdns_mhdp_secure_mailbox_recv_header(mhdp, MB_MODULE_ID_HDCP_TX,
                                                   HDCP2X_TX_IS_KM_STORED,
                                                   size);
        if (ret)
                goto err_is_km_stored;

        ret = cdns_mhdp_secure_mailbox_recv_data(mhdp, resp, size);
err_is_km_stored:
        mutex_unlock(&mhdp->mbox_mutex);

        return ret;
}

static int cdns_mhdp_hdcp_tx_config(struct cdns_mhdp_device *mhdp,
                                    u8 hdcp_cfg)
{
        int ret;

        mutex_lock(&mhdp->mbox_mutex);
        ret = cdns_mhdp_secure_mailbox_send(mhdp, MB_MODULE_ID_HDCP_TX,
                                            HDCP_TRAN_CONFIGURATION, 1, &hdcp_cfg);
        mutex_unlock(&mhdp->mbox_mutex);

        return ret;
}

static int cdns_mhdp_hdcp_set_config(struct cdns_mhdp_device *mhdp,
                                     u8 hdcp_config, bool enable)
{
        u16 hdcp_port_status;
        u32 ret_event;
        u8 hdcp_cfg;
        int ret;

        hdcp_cfg = hdcp_config | (enable ? 0x04 : 0) |
                   (HDCP_CONTENT_TYPE_0 << 3);
        cdns_mhdp_hdcp_tx_config(mhdp, hdcp_cfg);
        ret_event = cdns_mhdp_wait_for_sw_event(mhdp, CDNS_HDCP_TX_STATUS);
        if (!ret_event)
                return -1;

        ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
        if (ret || cdns_mhdp_hdcp_handle_status(mhdp, hdcp_port_status))
                return -1;

        return 0;
}

static int cdns_mhdp_hdcp_auth_check(struct cdns_mhdp_device *mhdp)
{
        u16 hdcp_port_status;
        u32 ret_event;
        int ret;

        ret_event = cdns_mhdp_wait_for_sw_event(mhdp, CDNS_HDCP_TX_STATUS);
        if (!ret_event)
                return -1;

        ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
        if (ret || cdns_mhdp_hdcp_handle_status(mhdp, hdcp_port_status))
                return -1;

        if (hdcp_port_status & 1) {
                dev_dbg(mhdp->dev, "Authentication completed successfully!\n");
                return 0;
        }

        dev_dbg(mhdp->dev, "Authentication failed\n");

        return -1;
}

static int cdns_mhdp_hdcp_check_receviers(struct cdns_mhdp_device *mhdp)
{
        u8 hdcp_rec_id[HDCP_MAX_RECEIVERS][HDCP_RECEIVER_ID_SIZE_BYTES];
        u8 hdcp_num_rec;
        u32 ret_event;

        ret_event = cdns_mhdp_wait_for_sw_event(mhdp,
                                                CDNS_HDCP_TX_IS_RCVR_ID_VALID);
        if (!ret_event)
                return -1;

        hdcp_num_rec = 0;
        memset(&hdcp_rec_id, 0, sizeof(hdcp_rec_id));
        cdns_mhdp_hdcp_rx_id_valid(mhdp, &hdcp_num_rec, (u8 *)hdcp_rec_id);
        cdns_mhdp_hdcp_rx_id_valid_response(mhdp, 1);

        return 0;
}

static int cdns_mhdp_hdcp_auth_22(struct cdns_mhdp_device *mhdp)
{
        u8 resp[HDCP_STATUS_SIZE];
        u16 hdcp_port_status;
        u32 ret_event;
        int ret;

        dev_dbg(mhdp->dev, "HDCP: Start 2.2 Authentication\n");
        ret_event = cdns_mhdp_wait_for_sw_event(mhdp,
                                                CDNS_HDCP2_TX_IS_KM_STORED);
        if (!ret_event)
                return -1;

        if (ret_event & CDNS_HDCP_TX_STATUS) {
                mhdp->sw_events &= ~CDNS_HDCP_TX_STATUS;
                ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
                if (ret || cdns_mhdp_hdcp_handle_status(mhdp, hdcp_port_status))
                        return -1;
        }

        cdns_mhdp_hdcp_tx_is_km_stored(mhdp, resp, sizeof(resp));
        cdns_mhdp_hdcp_km_stored_resp(mhdp, 0, NULL);

        if (cdns_mhdp_hdcp_check_receviers(mhdp))
                return -1;

        return 0;
}

static inline int cdns_mhdp_hdcp_auth_14(struct cdns_mhdp_device *mhdp)
{
        dev_dbg(mhdp->dev, "HDCP: Starting 1.4 Authentication\n");
        return cdns_mhdp_hdcp_check_receviers(mhdp);
}

static int cdns_mhdp_hdcp_auth(struct cdns_mhdp_device *mhdp,
                               u8 hdcp_config)
{
        int ret;

        ret = cdns_mhdp_hdcp_set_config(mhdp, hdcp_config, true);
        if (ret)
                goto auth_failed;

        if (hdcp_config == HDCP_TX_1)
                ret = cdns_mhdp_hdcp_auth_14(mhdp);
        else
                ret = cdns_mhdp_hdcp_auth_22(mhdp);

        if (ret)
                goto auth_failed;

        ret = cdns_mhdp_hdcp_auth_check(mhdp);
        if (ret)
                ret = cdns_mhdp_hdcp_auth_check(mhdp);

auth_failed:
        return ret;
}

static int _cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
{
        int ret;

        dev_dbg(mhdp->dev, "[%s:%d] HDCP is being disabled...\n",
                mhdp->connector.name, mhdp->connector.base.id);

        ret = cdns_mhdp_hdcp_set_config(mhdp, 0, false);

        return ret;
}

static int _cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type)
{
        int ret = -EINVAL;
        int tries = 3;
        u32 i;

        for (i = 0; i < tries; i++) {
                if (content_type == DRM_MODE_HDCP_CONTENT_TYPE0 ||
                    content_type == DRM_MODE_HDCP_CONTENT_TYPE1) {
                        ret = cdns_mhdp_hdcp_auth(mhdp, HDCP_TX_2);
                        if (!ret)
                                return 0;
                        _cdns_mhdp_hdcp_disable(mhdp);
                }

                if (content_type == DRM_MODE_HDCP_CONTENT_TYPE0) {
                        ret = cdns_mhdp_hdcp_auth(mhdp, HDCP_TX_1);
                        if (!ret)
                                return 0;
                        _cdns_mhdp_hdcp_disable(mhdp);
                }
        }

        dev_err(mhdp->dev, "HDCP authentication failed (%d tries/%d)\n",
                tries, ret);

        return ret;
}

static int cdns_mhdp_hdcp_check_link(struct cdns_mhdp_device *mhdp)
{
        u16 hdcp_port_status;
        int ret = 0;

        mutex_lock(&mhdp->hdcp.mutex);
        if (mhdp->hdcp.value == DRM_MODE_CONTENT_PROTECTION_UNDESIRED)
                goto out;

        ret = cdns_mhdp_hdcp_get_status(mhdp, &hdcp_port_status);
        if (!ret && hdcp_port_status & HDCP_PORT_STS_AUTH)
                goto out;

        dev_err(mhdp->dev,
                "[%s:%d] HDCP link failed, retrying authentication\n",
                mhdp->connector.name, mhdp->connector.base.id);

        ret = _cdns_mhdp_hdcp_disable(mhdp);
        if (ret) {
                mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
                schedule_work(&mhdp->hdcp.prop_work);
                goto out;
        }

        ret = _cdns_mhdp_hdcp_enable(mhdp, mhdp->hdcp.hdcp_content_type);
        if (ret) {
                mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_DESIRED;
                schedule_work(&mhdp->hdcp.prop_work);
        }
out:
        mutex_unlock(&mhdp->hdcp.mutex);
        return ret;
}

static void cdns_mhdp_hdcp_check_work(struct work_struct *work)
{
        struct delayed_work *d_work = to_delayed_work(work);
        struct cdns_mhdp_hdcp *hdcp = container_of(d_work,
                                                   struct cdns_mhdp_hdcp,
                                                   check_work);
        struct cdns_mhdp_device *mhdp = container_of(hdcp,
                                                     struct cdns_mhdp_device,
                                                     hdcp);

        if (!cdns_mhdp_hdcp_check_link(mhdp))
                schedule_delayed_work(&hdcp->check_work,
                                      DRM_HDCP_CHECK_PERIOD_MS);
}

static void cdns_mhdp_hdcp_prop_work(struct work_struct *work)
{
        struct cdns_mhdp_hdcp *hdcp = container_of(work,
                                                   struct cdns_mhdp_hdcp,
                                                   prop_work);
        struct cdns_mhdp_device *mhdp = container_of(hdcp,
                                                     struct cdns_mhdp_device,
                                                     hdcp);
        struct drm_device *dev = mhdp->connector.dev;
        struct drm_connector_state *state;

        drm_modeset_lock(&dev->mode_config.connection_mutex, NULL);
        mutex_lock(&mhdp->hdcp.mutex);
        if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
                state = mhdp->connector.state;
                state->content_protection = mhdp->hdcp.value;
        }
        mutex_unlock(&mhdp->hdcp.mutex);
        drm_modeset_unlock(&dev->mode_config.connection_mutex);
}

int cdns_mhdp_hdcp_enable(struct cdns_mhdp_device *mhdp, u8 content_type)
{
        int ret;

        mutex_lock(&mhdp->hdcp.mutex);
        ret = _cdns_mhdp_hdcp_enable(mhdp, content_type);
        if (ret)
                goto out;

        mhdp->hdcp.hdcp_content_type = content_type;
        mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_ENABLED;
        schedule_work(&mhdp->hdcp.prop_work);
        schedule_delayed_work(&mhdp->hdcp.check_work,
                              DRM_HDCP_CHECK_PERIOD_MS);
out:
        mutex_unlock(&mhdp->hdcp.mutex);
        return ret;
}

int cdns_mhdp_hdcp_disable(struct cdns_mhdp_device *mhdp)
{
        int ret = 0;

        mutex_lock(&mhdp->hdcp.mutex);
        if (mhdp->hdcp.value != DRM_MODE_CONTENT_PROTECTION_UNDESIRED) {
                mhdp->hdcp.value = DRM_MODE_CONTENT_PROTECTION_UNDESIRED;
                schedule_work(&mhdp->hdcp.prop_work);
                ret = _cdns_mhdp_hdcp_disable(mhdp);
        }
        mutex_unlock(&mhdp->hdcp.mutex);
        cancel_delayed_work_sync(&mhdp->hdcp.check_work);

        return ret;
}

void cdns_mhdp_hdcp_init(struct cdns_mhdp_device *mhdp)
{
        INIT_DELAYED_WORK(&mhdp->hdcp.check_work, cdns_mhdp_hdcp_check_work);
        INIT_WORK(&mhdp->hdcp.prop_work, cdns_mhdp_hdcp_prop_work);
        mutex_init(&mhdp->hdcp.mutex);
}