wd.c

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/*
 *
 * Intel Management Engine Interface (Intel MEI) Linux driver
 * Copyright (c) 2003-2012, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/device.h>
#include <linux/pci.h>
#include <linux/sched.h>
#include <linux/watchdog.h>

#include "mei_dev.h"
#include "hw.h"
#include "interface.h"
#include <linux/mei.h>

static const u8 mei_start_wd_params[] = { 0x02, 0x12, 0x13, 0x10 };
static const u8 mei_stop_wd_params[] = { 0x02, 0x02, 0x14, 0x10 };

const u8 mei_wd_state_independence_msg[3][4] = {
    {0x05, 0x02, 0x51, 0x10},
    {0x05, 0x02, 0x52, 0x10},
    {0x07, 0x02, 0x01, 0x10}
};

/*
 * AMT Watchdog Device
 */
#define INTEL_AMT_WATCHDOG_ID "INTCAMT"

/* UUIDs for AMT F/W clients */
const uuid_le mei_wd_guid = UUID_LE(0x05B79A6F, 0x4628, 0x4D7F, 0x89,
                        0x9D, 0xA9, 0x15, 0x14, 0xCB,
                        0x32, 0xAB);

static void mei_wd_set_start_timeout(struct mei_device *dev, u16 timeout)
{
    dev_dbg(&dev->pdev->dev, "wd: set timeout=%d.\n", timeout);
    memcpy(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE);
    memcpy(dev->wd_data + MEI_WD_HDR_SIZE, &timeout, sizeof(u16));
}

int mei_wd_host_init(struct mei_device *dev)
{
    mei_cl_init(&dev->wd_cl, dev);

    /* look for WD client and connect to it */
    dev->wd_cl.state = MEI_FILE_DISCONNECTED;
    dev->wd_timeout = MEI_WD_DEFAULT_TIMEOUT;
    dev->wd_state = MEI_WD_IDLE;

    /* find ME WD client */
    mei_me_cl_update_filext(dev, &dev->wd_cl,
                &mei_wd_guid, MEI_WD_HOST_CLIENT_ID);

    dev_dbg(&dev->pdev->dev, "wd: check client\n");
    if (MEI_FILE_CONNECTING != dev->wd_cl.state) {
        dev_info(&dev->pdev->dev, "wd: failed to find the client\n");
        return -ENOENT;
    }

    if (mei_connect(dev, &dev->wd_cl)) {
        dev_err(&dev->pdev->dev, "wd: failed to connect to the client\n");
        dev->wd_cl.state = MEI_FILE_DISCONNECTED;
        dev->wd_cl.host_client_id = 0;
        return -EIO;
    }
    dev->wd_cl.timer_count = CONNECT_TIMEOUT;

    return 0;
}

int mei_wd_send(struct mei_device *dev)
{
    struct mei_msg_hdr *mei_hdr;

    mei_hdr = (struct mei_msg_hdr *) &dev->wr_msg_buf[0];
    mei_hdr->host_addr = dev->wd_cl.host_client_id;
    mei_hdr->me_addr = dev->wd_cl.me_client_id;
    mei_hdr->msg_complete = 1;
    mei_hdr->reserved = 0;

    if (!memcmp(dev->wd_data, mei_start_wd_params, MEI_WD_HDR_SIZE))
        mei_hdr->length = MEI_WD_START_MSG_SIZE;
    else if (!memcmp(dev->wd_data, mei_stop_wd_params, MEI_WD_HDR_SIZE))
        mei_hdr->length = MEI_WD_STOP_MSG_SIZE;
    else
        return -EINVAL;

    return mei_write_message(dev, mei_hdr, dev->wd_data, mei_hdr->length);
}

int mei_wd_stop(struct mei_device *dev)
{
    int ret;

    if (dev->wd_cl.state != MEI_FILE_CONNECTED ||
        dev->wd_state != MEI_WD_RUNNING)
        return 0;

    memcpy(dev->wd_data, mei_stop_wd_params, MEI_WD_STOP_MSG_SIZE);

    dev->wd_state = MEI_WD_STOPPING;

    ret = mei_flow_ctrl_creds(dev, &dev->wd_cl);
    if (ret < 0)
        goto out;

    if (ret && dev->mei_host_buffer_is_empty) {
        ret = 0;
        dev->mei_host_buffer_is_empty = false;

        if (!mei_wd_send(dev)) {
            ret = mei_flow_ctrl_reduce(dev, &dev->wd_cl);
            if (ret)
                goto out;
        } else {
            dev_err(&dev->pdev->dev, "wd: send stop failed\n");
        }

        dev->wd_pending = false;
    } else {
        dev->wd_pending = true;
    }

    mutex_unlock(&dev->device_lock);

    ret = wait_event_interruptible_timeout(dev->wait_stop_wd,
                    dev->wd_state == MEI_WD_IDLE,
                    msecs_to_jiffies(MEI_WD_STOP_TIMEOUT));
    mutex_lock(&dev->device_lock);
    if (dev->wd_state == MEI_WD_IDLE) {
        dev_dbg(&dev->pdev->dev, "wd: stop completed ret=%d.\n", ret);
        ret = 0;
    } else {
        if (!ret)
            ret = -ETIMEDOUT;
        dev_warn(&dev->pdev->dev,
            "wd: stop failed to complete ret=%d.\n", ret);
    }

out:
    return ret;
}

/*
 * mei_wd_ops_start - wd start command from the watchdog core.
 *
 * @wd_dev - watchdog device struct
 *
 * returns 0 if success, negative errno code for failure
 */
static int mei_wd_ops_start(struct watchdog_device *wd_dev)
{
    int err = -ENODEV;
    struct mei_device *dev;

    dev = watchdog_get_drvdata(wd_dev);
    if (!dev)
        return -ENODEV;

    mutex_lock(&dev->device_lock);

    if (dev->dev_state != MEI_DEV_ENABLED) {
        dev_dbg(&dev->pdev->dev,
            "wd: dev_state != MEI_DEV_ENABLED  dev_state = %s\n",
            mei_dev_state_str(dev->dev_state));
        goto end_unlock;
    }

    if (dev->wd_cl.state != MEI_FILE_CONNECTED) {
        dev_dbg(&dev->pdev->dev,
            "MEI Driver is not connected to Watchdog Client\n");
        goto end_unlock;
    }

    mei_wd_set_start_timeout(dev, dev->wd_timeout);

    err = 0;
end_unlock:
    mutex_unlock(&dev->device_lock);
    return err;
}

/*
 * mei_wd_ops_stop -  wd stop command from the watchdog core.
 *
 * @wd_dev - watchdog device struct
 *
 * returns 0 if success, negative errno code for failure
 */
static int mei_wd_ops_stop(struct watchdog_device *wd_dev)
{
    struct mei_device *dev;

    dev = watchdog_get_drvdata(wd_dev);
    if (!dev)
        return -ENODEV;

    mutex_lock(&dev->device_lock);
    mei_wd_stop(dev);
    mutex_unlock(&dev->device_lock);

    return 0;
}

/*
 * mei_wd_ops_ping - wd ping command from the watchdog core.
 *
 * @wd_dev - watchdog device struct
 *
 * returns 0 if success, negative errno code for failure
 */
static int mei_wd_ops_ping(struct watchdog_device *wd_dev)
{
    int ret = 0;
    struct mei_device *dev;

    dev = watchdog_get_drvdata(wd_dev);
    if (!dev)
        return -ENODEV;

    mutex_lock(&dev->device_lock);

    if (dev->wd_cl.state != MEI_FILE_CONNECTED) {
        dev_err(&dev->pdev->dev, "wd: not connected.\n");
        ret = -ENODEV;
        goto end;
    }

    dev->wd_state = MEI_WD_RUNNING;

    /* Check if we can send the ping to HW*/
    if (dev->mei_host_buffer_is_empty &&
        mei_flow_ctrl_creds(dev, &dev->wd_cl) > 0) {

        dev->mei_host_buffer_is_empty = false;
        dev_dbg(&dev->pdev->dev, "wd: sending ping\n");

        if (mei_wd_send(dev)) {
            dev_err(&dev->pdev->dev, "wd: send failed.\n");
            ret = -EIO;
            goto end;
        }

        if (mei_flow_ctrl_reduce(dev, &dev->wd_cl)) {
            dev_err(&dev->pdev->dev,
                "wd: mei_flow_ctrl_reduce() failed.\n");
            ret = -EIO;
            goto end;
        }

    } else {
        dev->wd_pending = true;
    }

end:
    mutex_unlock(&dev->device_lock);
    return ret;
}

/*
 * mei_wd_ops_set_timeout - wd set timeout command from the watchdog core.
 *
 * @wd_dev - watchdog device struct
 * @timeout - timeout value to set
 *
 * returns 0 if success, negative errno code for failure
 */
static int mei_wd_ops_set_timeout(struct watchdog_device *wd_dev, unsigned int timeout)
{
    struct mei_device *dev;

    dev = watchdog_get_drvdata(wd_dev);
    if (!dev)
        return -ENODEV;

    /* Check Timeout value */
    if (timeout < MEI_WD_MIN_TIMEOUT || timeout > MEI_WD_MAX_TIMEOUT)
        return -EINVAL;

    mutex_lock(&dev->device_lock);

    dev->wd_timeout = timeout;
    wd_dev->timeout = timeout;
    mei_wd_set_start_timeout(dev, dev->wd_timeout);

    mutex_unlock(&dev->device_lock);

    return 0;
}

/*
 * Watchdog Device structs
 */
static const struct watchdog_ops wd_ops = {
        .owner = THIS_MODULE,
        .start = mei_wd_ops_start,
        .stop = mei_wd_ops_stop,
        .ping = mei_wd_ops_ping,
        .set_timeout = mei_wd_ops_set_timeout,
};
static const struct watchdog_info wd_info = {
        .identity = INTEL_AMT_WATCHDOG_ID,
        .options = WDIOF_KEEPALIVEPING |
               WDIOF_SETTIMEOUT |
               WDIOF_ALARMONLY,
};

static struct watchdog_device amt_wd_dev = {
        .info = &wd_info,
        .ops = &wd_ops,
        .timeout = MEI_WD_DEFAULT_TIMEOUT,
        .min_timeout = MEI_WD_MIN_TIMEOUT,
        .max_timeout = MEI_WD_MAX_TIMEOUT,
};


void mei_watchdog_register(struct mei_device *dev)
{
    if (watchdog_register_device(&amt_wd_dev)) {
        dev_err(&dev->pdev->dev,
            "wd: unable to register watchdog device.\n");
        dev->wd_interface_reg = false;
        return;
    }

    dev_dbg(&dev->pdev->dev,
        "wd: successfully register watchdog interface.\n");
    dev->wd_interface_reg = true;
    watchdog_set_drvdata(&amt_wd_dev, dev);
}

void mei_watchdog_unregister(struct mei_device *dev)
{
    if (!dev->wd_interface_reg)
        return;

    watchdog_set_drvdata(&amt_wd_dev, NULL);
    watchdog_unregister_device(&amt_wd_dev);
    dev->wd_interface_reg = false;
}