// SPDX-License-Identifier: GPL-2.0
/*
 * Xilinx Zynq MPSoC Power Management
 *
 *  Copyright (C) 2014-2019 Xilinx, Inc.
 *
 *  Davorin Mista <davorin.mista@aggios.com>
 *  Jolly Shah <jollys@xilinx.com>
 *  Rajan Vaja <rajan.vaja@xilinx.com>
 */

#include <linux/mailbox_client.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reboot.h>
#include <linux/suspend.h>

#include <linux/firmware/xlnx-zynqmp.h>
#include <linux/firmware/xlnx-event-manager.h>
#include <linux/mailbox/zynqmp-ipi-message.h>

/**
 * struct zynqmp_pm_work_struct - Wrapper for struct work_struct
 * @callback_work:      Work structure
 * @args:               Callback arguments
 */
struct zynqmp_pm_work_struct {
        struct work_struct callback_work;
        u32 args[CB_ARG_CNT];
};

/**
 * struct zynqmp_pm_event_info - event related information
 * @cb_fun:     Function pointer to store the callback function.
 * @cb_type:    Type of callback from pm_api_cb_id,
 *                      PM_NOTIFY_CB - for Error Events,
 *                      PM_INIT_SUSPEND_CB - for suspend callback.
 * @node_id:    Node-Id related to event.
 * @event:      Event Mask for the Error Event.
 * @wake:       Flag specifying whether the subsystem should be woken upon
 *              event notification.
 */
struct zynqmp_pm_event_info {
        event_cb_func_t cb_fun;
        enum pm_api_cb_id cb_type;
        u32 node_id;
        u32 event;
        bool wake;
};

static struct zynqmp_pm_work_struct *zynqmp_pm_init_suspend_work, *zynqmp_pm_init_restart_work;
static struct mbox_chan *rx_chan;

enum pm_suspend_mode {
        PM_SUSPEND_MODE_FIRST = 0,
        PM_SUSPEND_MODE_STD = PM_SUSPEND_MODE_FIRST,
        PM_SUSPEND_MODE_POWER_OFF,
};

#define PM_SUSPEND_MODE_FIRST   PM_SUSPEND_MODE_STD

static const char *const suspend_modes[] = {
        [PM_SUSPEND_MODE_STD] = "standard",
        [PM_SUSPEND_MODE_POWER_OFF] = "power-off",
};

static enum pm_suspend_mode suspend_mode = PM_SUSPEND_MODE_STD;

static void zynqmp_pm_get_callback_data(u32 *buf)
{
        zynqmp_pm_invoke_fn(GET_CALLBACK_DATA, buf, 0);
}

static void subsystem_restart_event_callback(const u32 *payload, void *data)
{
        /* First element is callback API ID, others are callback arguments */
        if (work_pending(&zynqmp_pm_init_restart_work->callback_work))
                return;

        /* Copy callback arguments into work's structure */
        memcpy(zynqmp_pm_init_restart_work->args, &payload[0],
               sizeof(zynqmp_pm_init_restart_work->args));

        queue_work(system_dfl_wq, &zynqmp_pm_init_restart_work->callback_work);
}

static void suspend_event_callback(const u32 *payload, void *data)
{
        /* First element is callback API ID, others are callback arguments */
        if (work_pending(&zynqmp_pm_init_suspend_work->callback_work))
                return;

        /* Copy callback arguments into work's structure */
        memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
               sizeof(zynqmp_pm_init_suspend_work->args));

        queue_work(system_dfl_wq, &zynqmp_pm_init_suspend_work->callback_work);
}

static irqreturn_t zynqmp_pm_isr(int irq, void *data)
{
        u32 payload[CB_PAYLOAD_SIZE];

        zynqmp_pm_get_callback_data(payload);

        /* First element is callback API ID, others are callback arguments */
        if (payload[0] == PM_INIT_SUSPEND_CB) {
                switch (payload[1]) {
                case SUSPEND_SYSTEM_SHUTDOWN:
                        orderly_poweroff(true);
                        break;
                case SUSPEND_POWER_REQUEST:
                        pm_suspend(PM_SUSPEND_MEM);
                        break;
                default:
                        pr_err("%s Unsupported InitSuspendCb reason code %d\n",
                               __func__, payload[1]);
                }
        } else {
                pr_err("%s() Unsupported Callback %d\n", __func__, payload[0]);
        }

        return IRQ_HANDLED;
}

static void ipi_receive_callback(struct mbox_client *cl, void *data)
{
        struct zynqmp_ipi_message *msg = (struct zynqmp_ipi_message *)data;
        u32 payload[CB_PAYLOAD_SIZE];
        int ret;

        memcpy(payload, msg->data, sizeof(msg->len));
        /* First element is callback API ID, others are callback arguments */
        if (payload[0] == PM_INIT_SUSPEND_CB) {
                if (work_pending(&zynqmp_pm_init_suspend_work->callback_work))
                        return;

                /* Copy callback arguments into work's structure */
                memcpy(zynqmp_pm_init_suspend_work->args, &payload[1],
                       sizeof(zynqmp_pm_init_suspend_work->args));

                queue_work(system_dfl_wq,
                           &zynqmp_pm_init_suspend_work->callback_work);

                /* Send NULL message to mbox controller to ack the message */
                ret = mbox_send_message(rx_chan, NULL);
                if (ret)
                        pr_err("IPI ack failed. Error %d\n", ret);
        }
}

/**
 * zynqmp_pm_subsystem_restart_work_fn - Initiate Subsystem restart
 * @work:       Pointer to work_struct
 *
 * Bottom-half of PM callback IRQ handler.
 */
static void zynqmp_pm_subsystem_restart_work_fn(struct work_struct *work)
{
        int ret;
        struct zynqmp_pm_work_struct *pm_work = container_of(work, struct zynqmp_pm_work_struct,
                                                             callback_work);

        /* First element is callback API ID, others are callback arguments */
        if (pm_work->args[0] == PM_NOTIFY_CB) {
                if (pm_work->args[2] == EVENT_SUBSYSTEM_RESTART) {
                        ret = zynqmp_pm_system_shutdown(ZYNQMP_PM_SHUTDOWN_TYPE_SETSCOPE_ONLY,
                                                        ZYNQMP_PM_SHUTDOWN_SUBTYPE_SUBSYSTEM);
                        if (ret) {
                                pr_err("unable to set shutdown scope\n");
                                return;
                        }

                        kernel_restart(NULL);
                } else {
                        pr_err("%s Unsupported Event - %d\n", __func__, pm_work->args[2]);
                }
        } else {
                pr_err("%s() Unsupported Callback %d\n", __func__, pm_work->args[0]);
        }
}

/**
 * zynqmp_pm_init_suspend_work_fn - Initialize suspend
 * @work:       Pointer to work_struct
 *
 * Bottom-half of PM callback IRQ handler.
 */
static void zynqmp_pm_init_suspend_work_fn(struct work_struct *work)
{
        struct zynqmp_pm_work_struct *pm_work =
                container_of(work, struct zynqmp_pm_work_struct, callback_work);

        if (pm_work->args[0] == SUSPEND_SYSTEM_SHUTDOWN) {
                orderly_poweroff(true);
        } else if (pm_work->args[0] == SUSPEND_POWER_REQUEST) {
                pm_suspend(PM_SUSPEND_MEM);
        } else {
                pr_err("%s Unsupported InitSuspendCb reason code %d.\n",
                       __func__, pm_work->args[0]);
        }
}

static ssize_t suspend_mode_show(struct device *dev,
                                 struct device_attribute *attr, char *buf)
{
        char *s = buf;
        int md;

        for (md = PM_SUSPEND_MODE_FIRST; md < ARRAY_SIZE(suspend_modes); md++)
                if (suspend_modes[md]) {
                        if (md == suspend_mode)
                                s += sprintf(s, "[%s] ", suspend_modes[md]);
                        else
                                s += sprintf(s, "%s ", suspend_modes[md]);
                }

        /* Convert last space to newline */
        if (s != buf)
                *(s - 1) = '\n';
        return (s - buf);
}

static ssize_t suspend_mode_store(struct device *dev,
                                  struct device_attribute *attr,
                                  const char *buf, size_t count)
{
        int md, ret = -EINVAL;

        for (md = PM_SUSPEND_MODE_FIRST; md < ARRAY_SIZE(suspend_modes); md++)
                if (suspend_modes[md] &&
                    sysfs_streq(suspend_modes[md], buf)) {
                        ret = 0;
                        break;
                }

        if (!ret && md != suspend_mode) {
                ret = zynqmp_pm_set_suspend_mode(md);
                if (likely(!ret))
                        suspend_mode = md;
        }

        return ret ? ret : count;
}

static DEVICE_ATTR_RW(suspend_mode);

static void unregister_event(struct device *dev, void *res)
{
        struct zynqmp_pm_event_info *event_info = res;

        xlnx_unregister_event(event_info->cb_type, event_info->node_id,
                              event_info->event, event_info->cb_fun, NULL);
}

static int register_event(struct device *dev, const enum pm_api_cb_id cb_type, const u32 node_id,
                          const u32 event, const bool wake, event_cb_func_t cb_fun)
{
        int ret;
        struct zynqmp_pm_event_info *event_info;

        event_info = devres_alloc(unregister_event, sizeof(struct zynqmp_pm_event_info),
                                  GFP_KERNEL);
        if (!event_info)
                return -ENOMEM;

        event_info->cb_type = cb_type;
        event_info->node_id = node_id;
        event_info->event = event;
        event_info->wake = wake;
        event_info->cb_fun = cb_fun;

        ret = xlnx_register_event(event_info->cb_type, event_info->node_id,
                                  event_info->event, event_info->wake, event_info->cb_fun, NULL);
        if (ret) {
                devres_free(event_info);
                return ret;
        }

        devres_add(dev, event_info);
        return 0;
}

static int zynqmp_pm_probe(struct platform_device *pdev)
{
        int ret, irq;
        u32 pm_api_version, pm_family_code, node_id;
        struct mbox_client *client;

        ret = zynqmp_pm_get_api_version(&pm_api_version);
        if (ret)
                return ret;

        /* Check PM API version number */
        if (pm_api_version < ZYNQMP_PM_VERSION)
                return -ENODEV;

        /*
         * First try to use Xilinx Event Manager by registering suspend_event_callback
         * for suspend/shutdown event.
         * If xlnx_register_event() returns -EACCES (Xilinx Event Manager
         * is not available to use) or -ENODEV(Xilinx Event Manager not compiled),
         * then use ipi-mailbox or interrupt method.
         */
        ret = register_event(&pdev->dev, PM_INIT_SUSPEND_CB, 0, 0, false,
                             suspend_event_callback);
        if (!ret) {
                zynqmp_pm_init_suspend_work = devm_kzalloc(&pdev->dev,
                                                           sizeof(struct zynqmp_pm_work_struct),
                                                           GFP_KERNEL);
                if (!zynqmp_pm_init_suspend_work)
                        return -ENOMEM;

                INIT_WORK(&zynqmp_pm_init_suspend_work->callback_work,
                          zynqmp_pm_init_suspend_work_fn);

                ret = zynqmp_pm_get_family_info(&pm_family_code);
                if (ret < 0)
                        return ret;

                if (pm_family_code == PM_VERSAL_NET_FAMILY_CODE)
                        node_id = PM_DEV_ACPU_0_0;
                else if (pm_family_code == PM_VERSAL_FAMILY_CODE)
                        node_id = PM_DEV_ACPU_0;
                else
                        return -ENODEV;

                ret = register_event(&pdev->dev, PM_NOTIFY_CB, node_id, EVENT_SUBSYSTEM_RESTART,
                                     false, subsystem_restart_event_callback);
                if (ret) {
                        dev_err(&pdev->dev, "Failed to Register with Xilinx Event manager %d\n",
                                ret);
                        return ret;
                }

                zynqmp_pm_init_restart_work = devm_kzalloc(&pdev->dev,
                                                           sizeof(struct zynqmp_pm_work_struct),
                                                           GFP_KERNEL);
                if (!zynqmp_pm_init_restart_work)
                        return -ENOMEM;

                INIT_WORK(&zynqmp_pm_init_restart_work->callback_work,
                          zynqmp_pm_subsystem_restart_work_fn);
        } else if (ret != -EACCES && ret != -ENODEV) {
                dev_err(&pdev->dev, "Failed to Register with Xilinx Event manager %d\n", ret);
                return ret;
        } else if (of_property_present(pdev->dev.of_node, "mboxes")) {
                zynqmp_pm_init_suspend_work =
                        devm_kzalloc(&pdev->dev,
                                     sizeof(struct zynqmp_pm_work_struct),
                                     GFP_KERNEL);
                if (!zynqmp_pm_init_suspend_work)
                        return -ENOMEM;

                INIT_WORK(&zynqmp_pm_init_suspend_work->callback_work,
                          zynqmp_pm_init_suspend_work_fn);
                client = devm_kzalloc(&pdev->dev, sizeof(*client), GFP_KERNEL);
                if (!client)
                        return -ENOMEM;

                client->dev = &pdev->dev;
                client->rx_callback = ipi_receive_callback;

                rx_chan = mbox_request_channel_byname(client, "rx");
                if (IS_ERR(rx_chan)) {
                        dev_err(&pdev->dev, "Failed to request rx channel\n");
                        return PTR_ERR(rx_chan);
                }
        } else if (of_property_present(pdev->dev.of_node, "interrupts")) {
                irq = platform_get_irq(pdev, 0);
                if (irq < 0)
                        return irq;

                ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
                                                zynqmp_pm_isr,
                                                IRQF_NO_SUSPEND | IRQF_ONESHOT,
                                                dev_name(&pdev->dev),
                                                &pdev->dev);
                if (ret) {
                        dev_err(&pdev->dev, "devm_request_threaded_irq '%d' failed with %d\n",
                                irq, ret);
                        return ret;
                }
        } else {
                dev_err(&pdev->dev, "Required property not found in DT node\n");
                return -ENOENT;
        }

        ret = sysfs_create_file(&pdev->dev.kobj, &dev_attr_suspend_mode.attr);
        if (ret)
                return ret;

        return 0;
}

static void zynqmp_pm_remove(struct platform_device *pdev)
{
        sysfs_remove_file(&pdev->dev.kobj, &dev_attr_suspend_mode.attr);

        if (!rx_chan)
                mbox_free_channel(rx_chan);
}

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

static struct platform_driver zynqmp_pm_platform_driver = {
        .probe = zynqmp_pm_probe,
        .remove = zynqmp_pm_remove,
        .driver = {
                .name = "zynqmp_power",
                .of_match_table = pm_of_match,
        },
};
module_platform_driver(zynqmp_pm_platform_driver);