// SPDX-License-Identifier: GPL-2.0-only
/*
 * Alt-mode implementation on ChromeOS EC.
 *
 * Copyright 2024 Google LLC
 * Author: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
 */
#include "cros_ec_typec.h"

#include <linux/mutex.h>
#include <linux/workqueue.h>
#include <linux/usb/typec_dp.h>
#include <linux/usb/typec_tbt.h>
#include <linux/usb/pd_vdo.h>

#include "cros_typec_altmode.h"

struct cros_typec_altmode_data {
        struct work_struct work;
        struct cros_typec_port *port;
        struct typec_altmode *alt;
        bool ap_mode_entry;

        struct mutex lock;
        u32 header;
        u32 *vdo_data;
        u8 vdo_size;

        u16 sid;
        u8 mode;
};

struct cros_typec_dp_data {
        struct cros_typec_altmode_data adata;
        struct typec_displayport_data data;
        bool configured;
        bool pending_status_update;
};

static void cros_typec_altmode_work(struct work_struct *work)
{
        struct cros_typec_altmode_data *data =
                container_of(work, struct cros_typec_altmode_data, work);

        mutex_lock(&data->lock);

        if (typec_altmode_vdm(data->alt, data->header, data->vdo_data,
                              data->vdo_size))
                dev_err(&data->alt->dev, "VDM 0x%x failed\n", data->header);

        data->header = 0;
        data->vdo_data = NULL;
        data->vdo_size = 0;

        mutex_unlock(&data->lock);
}

static int cros_typec_altmode_enter(struct typec_altmode *alt, u32 *vdo)
{
        struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);
        struct ec_params_typec_control req = {
                .port = adata->port->port_num,
                .command = TYPEC_CONTROL_COMMAND_ENTER_MODE,
        };
        int svdm_version;
        int ret;

        if (!adata->ap_mode_entry) {
                dev_warn(&alt->dev,
                         "EC does not support AP driven mode entry\n");
                return -EOPNOTSUPP;
        }

        if (adata->sid == USB_TYPEC_DP_SID)
                req.mode_to_enter = CROS_EC_ALTMODE_DP;
        else if (adata->sid == USB_TYPEC_TBT_SID)
                req.mode_to_enter = CROS_EC_ALTMODE_TBT;
        else
                return -EOPNOTSUPP;

        ret = cros_ec_cmd(adata->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
                          &req, sizeof(req), NULL, 0);
        if (ret < 0)
                return ret;

        svdm_version = typec_altmode_get_svdm_version(alt);
        if (svdm_version < 0)
                return svdm_version;

        mutex_lock(&adata->lock);

        adata->header = VDO(adata->sid, 1, svdm_version, CMD_ENTER_MODE);
        adata->header |= VDO_OPOS(adata->mode);
        adata->header |= VDO_CMDT(CMDT_RSP_ACK);
        adata->vdo_data = NULL;
        adata->vdo_size = 1;
        schedule_work(&adata->work);

        mutex_unlock(&adata->lock);
        return ret;
}

static int cros_typec_altmode_exit(struct typec_altmode *alt)
{
        struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);
        struct ec_params_typec_control req = {
                .port = adata->port->port_num,
                .command = TYPEC_CONTROL_COMMAND_EXIT_MODES,
        };
        int svdm_version;
        int ret;

        if (!adata->ap_mode_entry) {
                dev_warn(&alt->dev,
                         "EC does not support AP driven mode exit\n");
                return -EOPNOTSUPP;
        }

        ret = cros_ec_cmd(adata->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
                          &req, sizeof(req), NULL, 0);

        if (ret < 0)
                return ret;

        svdm_version = typec_altmode_get_svdm_version(alt);
        if (svdm_version < 0)
                return svdm_version;

        mutex_lock(&adata->lock);

        adata->header = VDO(adata->sid, 1, svdm_version, CMD_EXIT_MODE);
        adata->header |= VDO_OPOS(adata->mode);
        adata->header |= VDO_CMDT(CMDT_RSP_ACK);
        adata->vdo_data = NULL;
        adata->vdo_size = 1;
        schedule_work(&adata->work);

        mutex_unlock(&adata->lock);
        return ret;
}

static int cros_typec_displayport_vdm(struct typec_altmode *alt, u32 header,
                                      const u32 *data, int count)
{
        struct cros_typec_dp_data *dp_data = typec_altmode_get_drvdata(alt);
        struct cros_typec_altmode_data *adata = &dp_data->adata;


        int cmd_type = PD_VDO_CMDT(header);
        int cmd = PD_VDO_CMD(header);
        int svdm_version;

        svdm_version = typec_altmode_get_svdm_version(alt);
        if (svdm_version < 0)
                return svdm_version;

        mutex_lock(&adata->lock);

        switch (cmd_type) {
        case CMDT_INIT:
                if (PD_VDO_SVDM_VER(header) < svdm_version) {
                        typec_partner_set_svdm_version(adata->port->partner,
                                                       PD_VDO_SVDM_VER(header));
                        svdm_version = PD_VDO_SVDM_VER(header);
                }

                adata->header = VDO(adata->sid, 1, svdm_version, cmd);
                adata->header |= VDO_OPOS(adata->mode);

                /*
                 * DP_CMD_CONFIGURE: We can't actually do anything with the
                 * provided VDO yet so just send back an ACK.
                 *
                 * DP_CMD_STATUS_UPDATE: We wait for Mux changes to send
                 * DPStatus Acks.
                 */
                switch (cmd) {
                case DP_CMD_CONFIGURE:
                        dp_data->data.conf = *data;
                        adata->header |= VDO_CMDT(CMDT_RSP_ACK);
                        dp_data->configured = true;
                        schedule_work(&adata->work);
                        break;
                case DP_CMD_STATUS_UPDATE:
                        dp_data->pending_status_update = true;
                        break;
                default:
                        adata->header |= VDO_CMDT(CMDT_RSP_ACK);
                        schedule_work(&adata->work);
                        break;
                }

                break;
        default:
                break;
        }

        mutex_unlock(&adata->lock);
        return 0;
}

static int cros_typec_thunderbolt_vdm(struct typec_altmode *alt, u32 header,
                                      const u32 *data, int count)
{
        struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);

        int cmd_type = PD_VDO_CMDT(header);
        int cmd = PD_VDO_CMD(header);
        int svdm_version;

        svdm_version = typec_altmode_get_svdm_version(alt);
        if (svdm_version < 0)
                return svdm_version;

        mutex_lock(&adata->lock);

        switch (cmd_type) {
        case CMDT_INIT:
                if (PD_VDO_SVDM_VER(header) < svdm_version) {
                        typec_partner_set_svdm_version(adata->port->partner,
                                                       PD_VDO_SVDM_VER(header));
                        svdm_version = PD_VDO_SVDM_VER(header);
                }

                adata->header = VDO(adata->sid, 1, svdm_version, cmd);
                adata->header |= VDO_OPOS(adata->mode);

                switch (cmd) {
                case CMD_ENTER_MODE:
                        /* Don't respond to the enter mode vdm because it
                         * triggers mux configuration. This is handled directly
                         * by the cros_ec_typec driver so the Thunderbolt driver
                         * doesn't need to be involved.
                         */
                        break;
                default:
                        adata->header |= VDO_CMDT(CMDT_RSP_ACK);
                        schedule_work(&adata->work);
                        break;
                }

                break;
        default:
                break;
        }

        mutex_unlock(&adata->lock);
        return 0;
}


static int cros_typec_altmode_vdm(struct typec_altmode *alt, u32 header,
                                      const u32 *data, int count)
{
        struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);

        if (!adata->ap_mode_entry)
                return -EOPNOTSUPP;

        if (adata->sid == USB_TYPEC_DP_SID)
                return cros_typec_displayport_vdm(alt, header, data, count);

        if (adata->sid == USB_TYPEC_TBT_SID)
                return cros_typec_thunderbolt_vdm(alt, header, data, count);

        return -EINVAL;
}

static const struct typec_altmode_ops cros_typec_altmode_ops = {
        .enter = cros_typec_altmode_enter,
        .exit = cros_typec_altmode_exit,
        .vdm = cros_typec_altmode_vdm,
};

#if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
int cros_typec_displayport_status_update(struct typec_altmode *altmode,
                                         struct typec_displayport_data *data)
{
        struct cros_typec_dp_data *dp_data =
                typec_altmode_get_drvdata(altmode);
        struct cros_typec_altmode_data *adata = &dp_data->adata;

        if (!dp_data->pending_status_update) {
                dev_dbg(&altmode->dev,
                        "Got DPStatus without a pending request\n");
                return 0;
        }

        if (dp_data->configured && dp_data->data.conf != data->conf)
                dev_dbg(&altmode->dev,
                        "DP Conf doesn't match. Requested 0x%04x, Actual 0x%04x\n",
                        dp_data->data.conf, data->conf);

        mutex_lock(&adata->lock);

        dp_data->data = *data;
        dp_data->pending_status_update = false;
        adata->header |= VDO_CMDT(CMDT_RSP_ACK);
        adata->vdo_data = &dp_data->data.status;
        adata->vdo_size = 2;
        schedule_work(&adata->work);

        mutex_unlock(&adata->lock);

        return 0;
}

struct typec_altmode *
cros_typec_register_displayport(struct cros_typec_port *port,
                                struct typec_altmode_desc *desc,
                                bool ap_mode_entry)
{
        struct typec_altmode *alt;
        struct cros_typec_dp_data *dp_data;
        struct cros_typec_altmode_data *adata;

        alt = typec_port_register_altmode(port->port, desc);
        if (IS_ERR(alt))
                return alt;

        dp_data = devm_kzalloc(&alt->dev, sizeof(*dp_data), GFP_KERNEL);
        if (!dp_data) {
                typec_unregister_altmode(alt);
                return ERR_PTR(-ENOMEM);
        }

        adata = &dp_data->adata;
        INIT_WORK(&adata->work, cros_typec_altmode_work);
        mutex_init(&adata->lock);
        adata->alt = alt;
        adata->port = port;
        adata->ap_mode_entry = ap_mode_entry;
        adata->sid = desc->svid;
        adata->mode = desc->mode;

        typec_altmode_set_ops(alt, &cros_typec_altmode_ops);
        typec_altmode_set_drvdata(alt, adata);

        return alt;
}
#endif

#if IS_ENABLED(CONFIG_TYPEC_TBT_ALTMODE)
struct typec_altmode *
cros_typec_register_thunderbolt(struct cros_typec_port *port,
                                struct typec_altmode_desc *desc)
{
        struct typec_altmode *alt;
        struct cros_typec_altmode_data *adata;

        alt = typec_port_register_altmode(port->port, desc);
        if (IS_ERR(alt))
                return alt;

        adata = devm_kzalloc(&alt->dev, sizeof(*adata), GFP_KERNEL);
        if (!adata) {
                typec_unregister_altmode(alt);
                return ERR_PTR(-ENOMEM);
        }

        INIT_WORK(&adata->work, cros_typec_altmode_work);
        adata->alt = alt;
        adata->port = port;
        adata->ap_mode_entry = true;
        adata->sid = desc->svid;
        adata->mode = desc->mode;

        typec_altmode_set_ops(alt, &cros_typec_altmode_ops);
        typec_altmode_set_drvdata(alt, adata);

        return alt;
}
#endif