// SPDX-License-Identifier: GPL-2.0
/*
 * System Control and Management Interface (SCMI) System Power Protocol
 *
 * Copyright (C) 2020-2022 ARM Ltd.
 */

#define pr_fmt(fmt) "SCMI Notifications SYSTEM - " fmt

#include <linux/module.h>
#include <linux/scmi_protocol.h>

#include "protocols.h"
#include "notify.h"

/* Updated only after ALL the mandatory features for that version are merged */
#define SCMI_PROTOCOL_SUPPORTED_VERSION         0x20001

#define SCMI_SYSTEM_NUM_SOURCES         1

enum scmi_system_protocol_cmd {
        SYSTEM_POWER_STATE_NOTIFY = 0x5,
};

struct scmi_system_power_state_notify {
        __le32 notify_enable;
};

struct scmi_system_power_state_notifier_payld {
        __le32 agent_id;
        __le32 flags;
        __le32 system_state;
        __le32 timeout;
};

struct scmi_system_info {
        bool graceful_timeout_supported;
        bool power_state_notify_cmd;
};

static bool scmi_system_notify_supported(const struct scmi_protocol_handle *ph,
                                         u8 evt_id, u32 src_id)
{
        struct scmi_system_info *pinfo = ph->get_priv(ph);

        if (evt_id != SCMI_EVENT_SYSTEM_POWER_STATE_NOTIFIER)
                return false;

        return pinfo->power_state_notify_cmd;
}

static int scmi_system_request_notify(const struct scmi_protocol_handle *ph,
                                      bool enable)
{
        int ret;
        struct scmi_xfer *t;
        struct scmi_system_power_state_notify *notify;

        ret = ph->xops->xfer_get_init(ph, SYSTEM_POWER_STATE_NOTIFY,
                                      sizeof(*notify), 0, &t);
        if (ret)
                return ret;

        notify = t->tx.buf;
        notify->notify_enable = enable ? cpu_to_le32(BIT(0)) : 0;

        ret = ph->xops->do_xfer(ph, t);

        ph->xops->xfer_put(ph, t);
        return ret;
}

static int scmi_system_set_notify_enabled(const struct scmi_protocol_handle *ph,
                                          u8 evt_id, u32 src_id, bool enable)
{
        int ret;

        ret = scmi_system_request_notify(ph, enable);
        if (ret)
                pr_debug("FAIL_ENABLE - evt[%X] - ret:%d\n", evt_id, ret);

        return ret;
}

static void *
scmi_system_fill_custom_report(const struct scmi_protocol_handle *ph,
                               u8 evt_id, ktime_t timestamp,
                               const void *payld, size_t payld_sz,
                               void *report, u32 *src_id)
{
        size_t expected_sz;
        const struct scmi_system_power_state_notifier_payld *p = payld;
        struct scmi_system_power_state_notifier_report *r = report;
        struct scmi_system_info *pinfo = ph->get_priv(ph);

        expected_sz = pinfo->graceful_timeout_supported ?
                        sizeof(*p) : sizeof(*p) - sizeof(__le32);
        if (evt_id != SCMI_EVENT_SYSTEM_POWER_STATE_NOTIFIER ||
            payld_sz != expected_sz)
                return NULL;

        r->timestamp = timestamp;
        r->agent_id = le32_to_cpu(p->agent_id);
        r->flags = le32_to_cpu(p->flags);
        r->system_state = le32_to_cpu(p->system_state);
        if (pinfo->graceful_timeout_supported &&
            r->system_state == SCMI_SYSTEM_SHUTDOWN &&
            SCMI_SYSPOWER_IS_REQUEST_GRACEFUL(r->flags))
                r->timeout = le32_to_cpu(p->timeout);
        else
                r->timeout = 0x00;
        *src_id = 0;

        return r;
}

static const struct scmi_event system_events[] = {
        {
                .id = SCMI_EVENT_SYSTEM_POWER_STATE_NOTIFIER,
                .max_payld_sz =
                        sizeof(struct scmi_system_power_state_notifier_payld),
                .max_report_sz =
                        sizeof(struct scmi_system_power_state_notifier_report),
        },
};

static const struct scmi_event_ops system_event_ops = {
        .is_notify_supported = scmi_system_notify_supported,
        .set_notify_enabled = scmi_system_set_notify_enabled,
        .fill_custom_report = scmi_system_fill_custom_report,
};

static const struct scmi_protocol_events system_protocol_events = {
        .queue_sz = SCMI_PROTO_QUEUE_SZ,
        .ops = &system_event_ops,
        .evts = system_events,
        .num_events = ARRAY_SIZE(system_events),
        .num_sources = SCMI_SYSTEM_NUM_SOURCES,
};

static int scmi_system_protocol_init(const struct scmi_protocol_handle *ph)
{
        struct scmi_system_info *pinfo;

        dev_dbg(ph->dev, "System Power Version %d.%d\n",
                PROTOCOL_REV_MAJOR(ph->version), PROTOCOL_REV_MINOR(ph->version));

        pinfo = devm_kzalloc(ph->dev, sizeof(*pinfo), GFP_KERNEL);
        if (!pinfo)
                return -ENOMEM;

        if (PROTOCOL_REV_MAJOR(ph->version) >= 0x2)
                pinfo->graceful_timeout_supported = true;

        if (!ph->hops->protocol_msg_check(ph, SYSTEM_POWER_STATE_NOTIFY, NULL))
                pinfo->power_state_notify_cmd = true;

        return ph->set_priv(ph, pinfo);
}

static const struct scmi_protocol scmi_system = {
        .id = SCMI_PROTOCOL_SYSTEM,
        .owner = THIS_MODULE,
        .instance_init = &scmi_system_protocol_init,
        .ops = NULL,
        .events = &system_protocol_events,
        .supported_version = SCMI_PROTOCOL_SUPPORTED_VERSION,
};

DEFINE_SCMI_PROTOCOL_REGISTER_UNREGISTER(system, scmi_system)