// SPDX-License-Identifier: GPL-2.0-only
/*
 * ChromeOS EC multi-function device
 *
 * Copyright (C) 2012 Google, Inc
 *
 * The ChromeOS EC multi function device is used to mux all the requests
 * to the EC device for its multiple features: keyboard controller,
 * battery charging and regulator control, firmware update.
 */

#include <linux/cleanup.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/platform_data/cros_ec_commands.h>
#include <linux/platform_data/cros_ec_proto.h>
#include <linux/slab.h>
#include <linux/suspend.h>

#include "cros_ec.h"

static struct cros_ec_platform ec_p = {
        .ec_name = CROS_EC_DEV_NAME,
        .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_EC_INDEX),
};

static struct cros_ec_platform pd_p = {
        .ec_name = CROS_EC_DEV_PD_NAME,
        .cmd_offset = EC_CMD_PASSTHRU_OFFSET(CROS_EC_DEV_PD_INDEX),
};

static void cros_ec_device_free(void *data)
{
        struct cros_ec_device *ec_dev = data;

        mutex_destroy(&ec_dev->lock);
        lockdep_unregister_key(&ec_dev->lockdep_key);
}

struct cros_ec_device *cros_ec_device_alloc(struct device *dev)
{
        struct cros_ec_device *ec_dev;

        ec_dev = devm_kzalloc(dev, sizeof(*ec_dev), GFP_KERNEL);
        if (!ec_dev)
                return NULL;

        ec_dev->din_size = sizeof(struct ec_host_response) +
                           sizeof(struct ec_response_get_protocol_info) +
                           EC_MAX_RESPONSE_OVERHEAD;
        ec_dev->dout_size = sizeof(struct ec_host_request) +
                            sizeof(struct ec_params_rwsig_action) +
                            EC_MAX_REQUEST_OVERHEAD;

        ec_dev->din = devm_kzalloc(dev, ec_dev->din_size, GFP_KERNEL);
        if (!ec_dev->din)
                return NULL;

        ec_dev->dout = devm_kzalloc(dev, ec_dev->dout_size, GFP_KERNEL);
        if (!ec_dev->dout)
                return NULL;

        ec_dev->dev = dev;
        ec_dev->max_response = sizeof(struct ec_response_get_protocol_info);
        ec_dev->max_request = sizeof(struct ec_params_rwsig_action);
        ec_dev->suspend_timeout_ms = EC_HOST_SLEEP_TIMEOUT_DEFAULT;

        BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->event_notifier);
        BLOCKING_INIT_NOTIFIER_HEAD(&ec_dev->panic_notifier);

        lockdep_register_key(&ec_dev->lockdep_key);
        mutex_init(&ec_dev->lock);
        lockdep_set_class(&ec_dev->lock, &ec_dev->lockdep_key);

        if (devm_add_action_or_reset(dev, cros_ec_device_free, ec_dev))
                return NULL;

        return ec_dev;
}
EXPORT_SYMBOL(cros_ec_device_alloc);

/**
 * cros_ec_irq_handler() - top half part of the interrupt handler
 * @irq: IRQ id
 * @data: (ec_dev) Device with events to process.
 *
 * Return: Wakeup the bottom half
 */
static irqreturn_t cros_ec_irq_handler(int irq, void *data)
{
        struct cros_ec_device *ec_dev = data;

        ec_dev->last_event_time = cros_ec_get_time_ns();

        return IRQ_WAKE_THREAD;
}

/**
 * cros_ec_handle_event() - process and forward pending events on EC
 * @ec_dev: Device with events to process.
 *
 * Call this function in a loop when the kernel is notified that the EC has
 * pending events.
 *
 * Return: true if more events are still pending and this function should be
 * called again.
 */
static bool cros_ec_handle_event(struct cros_ec_device *ec_dev)
{
        bool wake_event;
        bool ec_has_more_events;
        int ret;

        ret = cros_ec_get_next_event(ec_dev, &wake_event, &ec_has_more_events);

        /*
         * Signal only if wake host events or any interrupt if
         * cros_ec_get_next_event() returned an error (default value for
         * wake_event is true)
         */
        if (wake_event && device_may_wakeup(ec_dev->dev))
                pm_wakeup_event(ec_dev->dev, 0);

        if (ret > 0)
                blocking_notifier_call_chain(&ec_dev->event_notifier,
                                             0, ec_dev);

        return ec_has_more_events;
}

/**
 * cros_ec_irq_thread() - bottom half part of the interrupt handler
 * @irq: IRQ id
 * @data: (ec_dev) Device with events to process.
 *
 * Return: Interrupt handled.
 */
irqreturn_t cros_ec_irq_thread(int irq, void *data)
{
        struct cros_ec_device *ec_dev = data;
        bool ec_has_more_events;

        do {
                ec_has_more_events = cros_ec_handle_event(ec_dev);
        } while (ec_has_more_events);

        return IRQ_HANDLED;
}
EXPORT_SYMBOL(cros_ec_irq_thread);

static int cros_ec_sleep_event(struct cros_ec_device *ec_dev, u8 sleep_event)
{
        int ret;
        TRAILING_OVERLAP(struct cros_ec_command, msg, data,
                union {
                        struct ec_params_host_sleep_event req0;
                        struct ec_params_host_sleep_event_v1 req1;
                        struct ec_response_host_sleep_event_v1 resp1;
                } u;
        ) __packed buf;

        memset(&buf, 0, sizeof(buf));

        if (ec_dev->host_sleep_v1) {
                buf.u.req1.sleep_event = sleep_event;
                buf.u.req1.suspend_params.sleep_timeout_ms =
                                ec_dev->suspend_timeout_ms;

                buf.msg.outsize = sizeof(buf.u.req1);
                if ((sleep_event == HOST_SLEEP_EVENT_S3_RESUME) ||
                    (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME))
                        buf.msg.insize = sizeof(buf.u.resp1);

                buf.msg.version = 1;

        } else {
                buf.u.req0.sleep_event = sleep_event;
                buf.msg.outsize = sizeof(buf.u.req0);
        }

        buf.msg.command = EC_CMD_HOST_SLEEP_EVENT;

        ret = cros_ec_cmd_xfer_status(ec_dev, &buf.msg);
        /* Report failure to transition to system wide suspend with a warning. */
        if (ret >= 0 && ec_dev->host_sleep_v1 &&
            (sleep_event == HOST_SLEEP_EVENT_S0IX_RESUME ||
             sleep_event == HOST_SLEEP_EVENT_S3_RESUME)) {
                ec_dev->last_resume_result =
                        buf.u.resp1.resume_response.sleep_transitions;

                WARN_ONCE(buf.u.resp1.resume_response.sleep_transitions &
                          EC_HOST_RESUME_SLEEP_TIMEOUT,
                          "EC detected sleep transition timeout. Total sleep transitions: %d",
                          buf.u.resp1.resume_response.sleep_transitions &
                          EC_HOST_RESUME_SLEEP_TRANSITIONS_MASK);
        }

        return ret;
}

static int cros_ec_ready_event(struct notifier_block *nb,
                               unsigned long queued_during_suspend,
                               void *_notify)
{
        struct cros_ec_device *ec_dev = container_of(nb, struct cros_ec_device,
                                                     notifier_ready);
        u32 host_event = cros_ec_get_host_event(ec_dev);

        if (host_event & EC_HOST_EVENT_MASK(EC_HOST_EVENT_INTERFACE_READY)) {
                mutex_lock(&ec_dev->lock);
                cros_ec_query_all(ec_dev);
                mutex_unlock(&ec_dev->lock);
                return NOTIFY_OK;
        }

        return NOTIFY_DONE;
}

/**
 * cros_ec_register() - Register a new ChromeOS EC, using the provided info.
 * @ec_dev: Device to register.
 *
 * Before calling this, allocate a pointer to a new device and then fill
 * in all the fields up to the --private-- marker.
 *
 * Return: 0 on success or negative error code.
 */
int cros_ec_register(struct cros_ec_device *ec_dev)
{
        struct device *dev = ec_dev->dev;
        int err;

        /* Send RWSIG continue to jump to RW for devices using RWSIG. */
        err = cros_ec_rwsig_continue(ec_dev);
        if (err)
                dev_info(dev, "Failed to continue RWSIG: %d\n", err);

        err = cros_ec_query_all(ec_dev);
        if (err) {
                dev_err(dev, "Cannot identify the EC: error %d\n", err);
                goto exit;
        }

        if (ec_dev->irq > 0) {
                err = devm_request_threaded_irq(dev, ec_dev->irq,
                                                cros_ec_irq_handler,
                                                cros_ec_irq_thread,
                                                IRQF_TRIGGER_LOW | IRQF_ONESHOT,
                                                "chromeos-ec", ec_dev);
                if (err) {
                        dev_err(dev, "Failed to request IRQ %d: %d\n",
                                ec_dev->irq, err);
                        goto exit;
                }
        }

        /* Register a platform device for the main EC instance */
        ec_dev->ec = platform_device_register_data(ec_dev->dev, "cros-ec-dev",
                                        PLATFORM_DEVID_AUTO, &ec_p,
                                        sizeof(struct cros_ec_platform));
        if (IS_ERR(ec_dev->ec)) {
                dev_err(ec_dev->dev,
                        "Failed to create CrOS EC platform device\n");
                err = PTR_ERR(ec_dev->ec);
                goto exit;
        }

        if (ec_dev->max_passthru) {
                /*
                 * Register a platform device for the PD behind the main EC.
                 * We make the following assumptions:
                 * - behind an EC, we have a pd
                 * - only one device added.
                 * - the EC is responsive at init time (it is not true for a
                 *   sensor hub).
                 */
                ec_dev->pd = platform_device_register_data(ec_dev->dev,
                                        "cros-ec-dev",
                                        PLATFORM_DEVID_AUTO, &pd_p,
                                        sizeof(struct cros_ec_platform));
                if (IS_ERR(ec_dev->pd)) {
                        dev_err(ec_dev->dev,
                                "Failed to create CrOS PD platform device\n");
                        err = PTR_ERR(ec_dev->pd);
                        goto exit;
                }
        }

        if (IS_ENABLED(CONFIG_OF) && dev->of_node) {
                err = devm_of_platform_populate(dev);
                if (err) {
                        dev_err(dev, "Failed to register sub-devices\n");
                        goto exit;
                }
        }

        /*
         * Clear sleep event - this will fail harmlessly on platforms that
         * don't implement the sleep event host command.
         */
        err = cros_ec_sleep_event(ec_dev, 0);
        if (err < 0)
                dev_dbg(ec_dev->dev, "Error %d clearing sleep event to ec\n",
                        err);

        if (ec_dev->mkbp_event_supported) {
                /*
                 * Register the notifier for EC_HOST_EVENT_INTERFACE_READY
                 * event.
                 */
                ec_dev->notifier_ready.notifier_call = cros_ec_ready_event;
                err = blocking_notifier_chain_register(&ec_dev->event_notifier,
                                                      &ec_dev->notifier_ready);
                if (err)
                        goto exit;
        }

        scoped_guard(mutex, &ec_dev->lock)
                ec_dev->registered = true;

        dev_info(dev, "Chrome EC device registered\n");

        /*
         * Unlock EC that may be waiting for AP to process MKBP events.
         * If the AP takes to long to answer, the EC would stop sending events.
         */
        if (ec_dev->mkbp_event_supported)
                cros_ec_irq_thread(0, ec_dev);

        return 0;
exit:
        platform_device_unregister(ec_dev->ec);
        platform_device_unregister(ec_dev->pd);
        return err;
}
EXPORT_SYMBOL(cros_ec_register);

/**
 * cros_ec_unregister() - Remove a ChromeOS EC.
 * @ec_dev: Device to unregister.
 *
 * Call this to deregister a ChromeOS EC, then clean up any private data.
 *
 * Return: 0 on success or negative error code.
 */
void cros_ec_unregister(struct cros_ec_device *ec_dev)
{
        scoped_guard(mutex, &ec_dev->lock)
                ec_dev->registered = false;

        if (ec_dev->mkbp_event_supported)
                blocking_notifier_chain_unregister(&ec_dev->event_notifier,
                                                   &ec_dev->notifier_ready);
        platform_device_unregister(ec_dev->pd);
        platform_device_unregister(ec_dev->ec);
}
EXPORT_SYMBOL(cros_ec_unregister);

#ifdef CONFIG_PM_SLEEP
static void cros_ec_send_suspend_event(struct cros_ec_device *ec_dev)
{
        int ret;
        u8 sleep_event;

        sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
                      HOST_SLEEP_EVENT_S3_SUSPEND :
                      HOST_SLEEP_EVENT_S0IX_SUSPEND;

        ret = cros_ec_sleep_event(ec_dev, sleep_event);
        if (ret < 0)
                dev_dbg(ec_dev->dev, "Error %d sending suspend event to ec\n",
                        ret);
}

/**
 * cros_ec_suspend_prepare() - Handle a suspend prepare operation for the ChromeOS EC device.
 * @ec_dev: Device to suspend.
 *
 * This can be called by drivers to handle a suspend prepare stage of suspend.
 *
 * Return: 0 always.
 */
int cros_ec_suspend_prepare(struct cros_ec_device *ec_dev)
{
        cros_ec_send_suspend_event(ec_dev);
        return 0;
}
EXPORT_SYMBOL(cros_ec_suspend_prepare);

static void cros_ec_disable_irq(struct cros_ec_device *ec_dev)
{
        struct device *dev = ec_dev->dev;
        if (device_may_wakeup(dev))
                ec_dev->wake_enabled = !enable_irq_wake(ec_dev->irq);
        else
                ec_dev->wake_enabled = false;

        disable_irq(ec_dev->irq);
        ec_dev->suspended = true;
}

/**
 * cros_ec_suspend_late() - Handle a suspend late operation for the ChromeOS EC device.
 * @ec_dev: Device to suspend.
 *
 * This can be called by drivers to handle a suspend late stage of suspend.
 *
 * Return: 0 always.
 */
int cros_ec_suspend_late(struct cros_ec_device *ec_dev)
{
        cros_ec_disable_irq(ec_dev);
        return 0;
}
EXPORT_SYMBOL(cros_ec_suspend_late);

/**
 * cros_ec_suspend() - Handle a suspend operation for the ChromeOS EC device.
 * @ec_dev: Device to suspend.
 *
 * This can be called by drivers to handle a suspend event.
 *
 * Return: 0 always.
 */
int cros_ec_suspend(struct cros_ec_device *ec_dev)
{
        cros_ec_suspend_prepare(ec_dev);
        cros_ec_suspend_late(ec_dev);
        return 0;
}
EXPORT_SYMBOL(cros_ec_suspend);

static void cros_ec_report_events_during_suspend(struct cros_ec_device *ec_dev)
{
        bool wake_event;

        while (ec_dev->mkbp_event_supported &&
               cros_ec_get_next_event(ec_dev, &wake_event, NULL) > 0) {
                blocking_notifier_call_chain(&ec_dev->event_notifier,
                                             1, ec_dev);

                if (wake_event && device_may_wakeup(ec_dev->dev))
                        pm_wakeup_event(ec_dev->dev, 0);
        }
}

static void cros_ec_send_resume_event(struct cros_ec_device *ec_dev)
{
        int ret;
        u8 sleep_event;

        sleep_event = (!IS_ENABLED(CONFIG_ACPI) || pm_suspend_via_firmware()) ?
                      HOST_SLEEP_EVENT_S3_RESUME :
                      HOST_SLEEP_EVENT_S0IX_RESUME;

        ret = cros_ec_sleep_event(ec_dev, sleep_event);
        if (ret < 0)
                dev_dbg(ec_dev->dev, "Error %d sending resume event to ec\n",
                        ret);
}

/**
 * cros_ec_resume_complete() - Handle a resume complete operation for the ChromeOS EC device.
 * @ec_dev: Device to resume.
 *
 * This can be called by drivers to handle a resume complete stage of resume.
 */
void cros_ec_resume_complete(struct cros_ec_device *ec_dev)
{
        cros_ec_send_resume_event(ec_dev);

        /*
         * Let the mfd devices know about events that occur during
         * suspend. This way the clients know what to do with them.
         */
        cros_ec_report_events_during_suspend(ec_dev);
}
EXPORT_SYMBOL(cros_ec_resume_complete);

static void cros_ec_enable_irq(struct cros_ec_device *ec_dev)
{
        ec_dev->suspended = false;
        enable_irq(ec_dev->irq);

        if (ec_dev->wake_enabled)
                disable_irq_wake(ec_dev->irq);
}

/**
 * cros_ec_resume_early() - Handle a resume early operation for the ChromeOS EC device.
 * @ec_dev: Device to resume.
 *
 * This can be called by drivers to handle a resume early stage of resume.
 *
 * Return: 0 always.
 */
int cros_ec_resume_early(struct cros_ec_device *ec_dev)
{
        cros_ec_enable_irq(ec_dev);
        return 0;
}
EXPORT_SYMBOL(cros_ec_resume_early);

/**
 * cros_ec_resume() - Handle a resume operation for the ChromeOS EC device.
 * @ec_dev: Device to resume.
 *
 * This can be called by drivers to handle a resume event.
 *
 * Return: 0 always.
 */
int cros_ec_resume(struct cros_ec_device *ec_dev)
{
        cros_ec_resume_early(ec_dev);
        cros_ec_resume_complete(ec_dev);
        return 0;
}
EXPORT_SYMBOL(cros_ec_resume);

#endif

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("ChromeOS EC core driver");