/*
 *
 * 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/pci.h>
#include <linux/sched.h>
#include <linux/wait.h>
#include <linux/delay.h>

#include <linux/mei.h>

#include "mei_dev.h"
#include "hbm.h"
#include "interface.h"


/**
 * mei_io_list_flush - removes list entry belonging to cl.
 *
 * @list:  An instance of our list structure
 * @cl: host client
 */
void mei_io_list_flush(struct mei_cl_cb *list, struct mei_cl *cl)
{
	struct mei_cl_cb *cb;
	struct mei_cl_cb *next;

	list_for_each_entry_safe(cb, next, &list->list, list) {
		if (cb->cl && mei_cl_cmp_id(cl, cb->cl))
			list_del(&cb->list);
	}
}

/**
 * mei_io_cb_free - free mei_cb_private related memory
 *
 * @cb: mei callback struct
 */
void mei_io_cb_free(struct mei_cl_cb *cb)
{
	if (cb == NULL)
		return;

	kfree(cb->request_buffer.data);
	kfree(cb->response_buffer.data);
	kfree(cb);
}

/**
 * mei_io_cb_init - allocate and initialize io callback
 *
 * @cl - mei client
 * @file: pointer to file structure
 *
 * returns mei_cl_cb pointer or NULL;
 */
struct mei_cl_cb *mei_io_cb_init(struct mei_cl *cl, struct file *fp)
{
	struct mei_cl_cb *cb;

	cb = kzalloc(sizeof(struct mei_cl_cb), GFP_KERNEL);
	if (!cb)
		return NULL;

	mei_io_list_init(cb);

	cb->file_object = fp;
	cb->cl = cl;
	cb->buf_idx = 0;
	return cb;
}

/**
 * mei_io_cb_alloc_req_buf - allocate request buffer
 *
 * @cb -  io callback structure
 * @size: size of the buffer
 *
 * returns 0 on success
 *         -EINVAL if cb is NULL
 *         -ENOMEM if allocation failed
 */
int mei_io_cb_alloc_req_buf(struct mei_cl_cb *cb, size_t length)
{
	if (!cb)
		return -EINVAL;

	if (length == 0)
		return 0;

	cb->request_buffer.data = kmalloc(length, GFP_KERNEL);
	if (!cb->request_buffer.data)
		return -ENOMEM;
	cb->request_buffer.size = length;
	return 0;
}
/**
 * mei_io_cb_alloc_req_buf - allocate respose buffer
 *
 * @cb -  io callback structure
 * @size: size of the buffer
 *
 * returns 0 on success
 *         -EINVAL if cb is NULL
 *         -ENOMEM if allocation failed
 */
int mei_io_cb_alloc_resp_buf(struct mei_cl_cb *cb, size_t length)
{
	if (!cb)
		return -EINVAL;

	if (length == 0)
		return 0;

	cb->response_buffer.data = kmalloc(length, GFP_KERNEL);
	if (!cb->response_buffer.data)
		return -ENOMEM;
	cb->response_buffer.size = length;
	return 0;
}



/**
 * mei_cl_flush_queues - flushes queue lists belonging to cl.
 *
 * @dev: the device structure
 * @cl: host client
 */
int mei_cl_flush_queues(struct mei_cl *cl)
{
	if (!cl || !cl->dev)
		return -EINVAL;

	dev_dbg(&cl->dev->pdev->dev, "remove list entry belonging to cl\n");
	mei_io_list_flush(&cl->dev->read_list, cl);
	mei_io_list_flush(&cl->dev->write_list, cl);
	mei_io_list_flush(&cl->dev->write_waiting_list, cl);
	mei_io_list_flush(&cl->dev->ctrl_wr_list, cl);
	mei_io_list_flush(&cl->dev->ctrl_rd_list, cl);
	mei_io_list_flush(&cl->dev->amthif_cmd_list, cl);
	mei_io_list_flush(&cl->dev->amthif_rd_complete_list, cl);
	return 0;
}

/**
 * mei_me_cl_by_uuid - locate index of me client
 *
 * @dev: mei device
 * returns me client index or -ENOENT if not found
 */
int mei_me_cl_by_uuid(const struct mei_device *dev, const uuid_le *uuid)
{
	int i, res = -ENOENT;

	for (i = 0; i < dev->me_clients_num; ++i)
		if (uuid_le_cmp(*uuid,
				dev->me_clients[i].props.protocol_name) == 0) {
			res = i;
			break;
		}

	return res;
}


/**
 * mei_me_cl_by_id return index to me_clients for client_id
 *
 * @dev: the device structure
 * @client_id: me client id
 *
 * Locking: called under "dev->device_lock" lock
 *
 * returns index on success, -ENOENT on failure.
 */

int mei_me_cl_by_id(struct mei_device *dev, u8 client_id)
{
	int i;
	for (i = 0; i < dev->me_clients_num; i++)
		if (dev->me_clients[i].client_id == client_id)
			break;
	if (WARN_ON(dev->me_clients[i].client_id != client_id))
		return -ENOENT;

	if (i == dev->me_clients_num)
		return -ENOENT;

	return i;
}

/**
 * mei_cl_init - initializes intialize cl.
 *
 * @cl: host client to be initialized
 * @dev: mei device
 */
void mei_cl_init(struct mei_cl *cl, struct mei_device *dev)
{
	memset(cl, 0, sizeof(struct mei_cl));
	init_waitqueue_head(&cl->wait);
	init_waitqueue_head(&cl->rx_wait);
	init_waitqueue_head(&cl->tx_wait);
	INIT_LIST_HEAD(&cl->link);
	cl->reading_state = MEI_IDLE;
	cl->writing_state = MEI_IDLE;
	cl->dev = dev;
}

/**
 * mei_cl_allocate - allocates cl  structure and sets it up.
 *
 * @dev: mei device
 * returns  The allocated file or NULL on failure
 */
struct mei_cl *mei_cl_allocate(struct mei_device *dev)
{
	struct mei_cl *cl;

	cl = kmalloc(sizeof(struct mei_cl), GFP_KERNEL);
	if (!cl)
		return NULL;

	mei_cl_init(cl, dev);

	return cl;
}


/**
 * mei_me_cl_link - create link between host and me clinet and add
 *   me_cl to the list
 *
 * @dev: the device structure
 * @cl: link between me and host client assocated with opened file descriptor
 * @uuid: uuid of ME client
 * @client_id: id of the host client
 *
 * returns ME client index if ME client
 *	-EINVAL on incorrect values
 *	-ENONET if client not found
 */
int mei_me_cl_link(struct mei_device *dev, struct mei_cl *cl,
			const uuid_le *uuid, u8 host_cl_id)
{
	int i;

	if (!dev || !cl || !uuid)
		return -EINVAL;

	/* check for valid client id */
	i = mei_me_cl_by_uuid(dev, uuid);
	if (i >= 0) {
		cl->me_client_id = dev->me_clients[i].client_id;
		cl->state = MEI_FILE_CONNECTING;
		cl->host_client_id = host_cl_id;

		list_add_tail(&cl->link, &dev->file_list);
		return (u8)i;
	}

	return -ENOENT;
}
/**
 * mei_me_cl_unlink - remove me_cl from the list
 *
 * @dev: the device structure
 * @host_client_id: host client id to be removed
 */
void mei_me_cl_unlink(struct mei_device *dev, struct mei_cl *cl)
{
	struct mei_cl *pos, *next;
	list_for_each_entry_safe(pos, next, &dev->file_list, link) {
		if (cl->host_client_id == pos->host_client_id) {
			dev_dbg(&dev->pdev->dev, "remove host client = %d, ME client = %d\n",
					pos->host_client_id, pos->me_client_id);
			list_del_init(&pos->link);
			break;
		}
	}
}


void mei_host_client_init(struct work_struct *work)
{
	struct mei_device *dev = container_of(work,
					      struct mei_device, init_work);
	struct mei_client_properties *client_props;
	int i;

	mutex_lock(&dev->device_lock);

	bitmap_zero(dev->host_clients_map, MEI_CLIENTS_MAX);
	dev->open_handle_count = 0;

	/*
	 * Reserving the first three client IDs
	 * 0: Reserved for MEI Bus Message communications
	 * 1: Reserved for Watchdog
	 * 2: Reserved for AMTHI
	 */
	bitmap_set(dev->host_clients_map, 0, 3);

	for (i = 0; i < dev->me_clients_num; i++) {
		client_props = &dev->me_clients[i].props;

		if (!uuid_le_cmp(client_props->protocol_name, mei_amthi_guid))
			mei_amthif_host_init(dev);
		else if (!uuid_le_cmp(client_props->protocol_name, mei_wd_guid))
			mei_wd_host_init(dev);
	}

	dev->dev_state = MEI_DEV_ENABLED;

	mutex_unlock(&dev->device_lock);
}


/**
 * mei_disconnect_host_client - sends disconnect message to fw from host client.
 *
 * @dev: the device structure
 * @cl: private data of the file object
 *
 * Locking: called under "dev->device_lock" lock
 *
 * returns 0 on success, <0 on failure.
 */
int mei_disconnect_host_client(struct mei_device *dev, struct mei_cl *cl)
{
	struct mei_cl_cb *cb;
	int rets, err;

	if (!dev || !cl)
		return -ENODEV;

	if (cl->state != MEI_FILE_DISCONNECTING)
		return 0;

	cb = mei_io_cb_init(cl, NULL);
	if (!cb)
		return -ENOMEM;

	cb->fop_type = MEI_FOP_CLOSE;
	if (dev->mei_host_buffer_is_empty) {
		dev->mei_host_buffer_is_empty = false;
		if (mei_hbm_cl_disconnect_req(dev, cl)) {
			rets = -ENODEV;
			dev_err(&dev->pdev->dev, "failed to disconnect.\n");
			goto free;
		}
		mdelay(10); /* Wait for hardware disconnection ready */
		list_add_tail(&cb->list, &dev->ctrl_rd_list.list);
	} else {
		dev_dbg(&dev->pdev->dev, "add disconnect cb to control write list\n");
		list_add_tail(&cb->list, &dev->ctrl_wr_list.list);

	}
	mutex_unlock(&dev->device_lock);

	err = wait_event_timeout(dev->wait_recvd_msg,
			MEI_FILE_DISCONNECTED == cl->state,
			mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT));

	mutex_lock(&dev->device_lock);
	if (MEI_FILE_DISCONNECTED == cl->state) {
		rets = 0;
		dev_dbg(&dev->pdev->dev, "successfully disconnected from FW client.\n");
	} else {
		rets = -ENODEV;
		if (MEI_FILE_DISCONNECTED != cl->state)
			dev_dbg(&dev->pdev->dev, "wrong status client disconnect.\n");

		if (err)
			dev_dbg(&dev->pdev->dev,
					"wait failed disconnect err=%08x\n",
					err);

		dev_dbg(&dev->pdev->dev, "failed to disconnect from FW client.\n");
	}

	mei_io_list_flush(&dev->ctrl_rd_list, cl);
	mei_io_list_flush(&dev->ctrl_wr_list, cl);
free:
	mei_io_cb_free(cb);
	return rets;
}


/**
 * mei_other_client_is_connecting - checks if other
 *    client with the same client id is connected.
 *
 * @dev: the device structure
 * @cl: private data of the file object
 *
 * returns 1 if other client is connected, 0 - otherwise.
 */
int mei_other_client_is_connecting(struct mei_device *dev,
				struct mei_cl *cl)
{
	struct mei_cl *cl_pos = NULL;
	struct mei_cl *cl_next = NULL;

	list_for_each_entry_safe(cl_pos, cl_next, &dev->file_list, link) {
		if ((cl_pos->state == MEI_FILE_CONNECTING) &&
			(cl_pos != cl) &&
			cl->me_client_id == cl_pos->me_client_id)
			return 1;

	}
	return 0;
}

/**
 * mei_flow_ctrl_creds - checks flow_control credentials.
 *
 * @dev: the device structure
 * @cl: private data of the file object
 *
 * returns 1 if mei_flow_ctrl_creds >0, 0 - otherwise.
 *	-ENOENT if mei_cl is not present
 *	-EINVAL if single_recv_buf == 0
 */
int mei_flow_ctrl_creds(struct mei_device *dev, struct mei_cl *cl)
{
	int i;

	if (!dev->me_clients_num)
		return 0;

	if (cl->mei_flow_ctrl_creds > 0)
		return 1;

	for (i = 0; i < dev->me_clients_num; i++) {
		struct mei_me_client  *me_cl = &dev->me_clients[i];
		if (me_cl->client_id == cl->me_client_id) {
			if (me_cl->mei_flow_ctrl_creds) {
				if (WARN_ON(me_cl->props.single_recv_buf == 0))
					return -EINVAL;
				return 1;
			} else {
				return 0;
			}
		}
	}
	return -ENOENT;
}

/**
 * mei_flow_ctrl_reduce - reduces flow_control.
 *
 * @dev: the device structure
 * @cl: private data of the file object
 * @returns
 *	0 on success
 *	-ENOENT when me client is not found
 *	-EINVAL when ctrl credits are <= 0
 */
int mei_flow_ctrl_reduce(struct mei_device *dev, struct mei_cl *cl)
{
	int i;

	if (!dev->me_clients_num)
		return -ENOENT;

	for (i = 0; i < dev->me_clients_num; i++) {
		struct mei_me_client  *me_cl = &dev->me_clients[i];
		if (me_cl->client_id == cl->me_client_id) {
			if (me_cl->props.single_recv_buf != 0) {
				if (WARN_ON(me_cl->mei_flow_ctrl_creds <= 0))
					return -EINVAL;
				dev->me_clients[i].mei_flow_ctrl_creds--;
			} else {
				if (WARN_ON(cl->mei_flow_ctrl_creds <= 0))
					return -EINVAL;
				cl->mei_flow_ctrl_creds--;
			}
			return 0;
		}
	}
	return -ENOENT;
}



/**
 * mei_ioctl_connect_client - the connect to fw client IOCTL function
 *
 * @dev: the device structure
 * @data: IOCTL connect data, input and output parameters
 * @file: private data of the file object
 *
 * Locking: called under "dev->device_lock" lock
 *
 * returns 0 on success, <0 on failure.
 */
int mei_ioctl_connect_client(struct file *file,
			struct mei_connect_client_data *data)
{
	struct mei_device *dev;
	struct mei_cl_cb *cb;
	struct mei_client *client;
	struct mei_cl *cl;
	long timeout = mei_secs_to_jiffies(MEI_CL_CONNECT_TIMEOUT);
	int i;
	int err;
	int rets;

	cl = file->private_data;
	if (WARN_ON(!cl || !cl->dev))
		return -ENODEV;

	dev = cl->dev;

	dev_dbg(&dev->pdev->dev, "mei_ioctl_connect_client() Entry\n");

	/* buffered ioctl cb */
	cb = mei_io_cb_init(cl, file);
	if (!cb) {
		rets = -ENOMEM;
		goto end;
	}

	cb->fop_type = MEI_FOP_IOCTL;

	if (dev->dev_state != MEI_DEV_ENABLED) {
		rets = -ENODEV;
		goto end;
	}
	if (cl->state != MEI_FILE_INITIALIZING &&
	    cl->state != MEI_FILE_DISCONNECTED) {
		rets = -EBUSY;
		goto end;
	}

	/* find ME client we're trying to connect to */
	i = mei_me_cl_by_uuid(dev, &data->in_client_uuid);
	if (i >= 0 && !dev->me_clients[i].props.fixed_address) {
		cl->me_client_id = dev->me_clients[i].client_id;
		cl->state = MEI_FILE_CONNECTING;
	}

	dev_dbg(&dev->pdev->dev, "Connect to FW Client ID = %d\n",
			cl->me_client_id);
	dev_dbg(&dev->pdev->dev, "FW Client - Protocol Version = %d\n",
			dev->me_clients[i].props.protocol_version);
	dev_dbg(&dev->pdev->dev, "FW Client - Max Msg Len = %d\n",
			dev->me_clients[i].props.max_msg_length);

	/* if we're connecting to amthi client then we will use the
	 * existing connection
	 */
	if (uuid_le_cmp(data->in_client_uuid, mei_amthi_guid) == 0) {
		dev_dbg(&dev->pdev->dev, "FW Client is amthi\n");
		if (dev->iamthif_cl.state != MEI_FILE_CONNECTED) {
			rets = -ENODEV;
			goto end;
		}
		clear_bit(cl->host_client_id, dev->host_clients_map);
		mei_me_cl_unlink(dev, cl);

		kfree(cl);
		cl = NULL;
		file->private_data = &dev->iamthif_cl;

		client = &data->out_client_properties;
		client->max_msg_length =
			dev->me_clients[i].props.max_msg_length;
		client->protocol_version =
			dev->me_clients[i].props.protocol_version;
		rets = dev->iamthif_cl.status;

		goto end;
	}

	if (cl->state != MEI_FILE_CONNECTING) {
		rets = -ENODEV;
		goto end;
	}


	/* prepare the output buffer */
	client = &data->out_client_properties;
	client->max_msg_length = dev->me_clients[i].props.max_msg_length;
	client->protocol_version = dev->me_clients[i].props.protocol_version;
	dev_dbg(&dev->pdev->dev, "Can connect?\n");
	if (dev->mei_host_buffer_is_empty
	    && !mei_other_client_is_connecting(dev, cl)) {
		dev_dbg(&dev->pdev->dev, "Sending Connect Message\n");
		dev->mei_host_buffer_is_empty = false;
		if (mei_hbm_cl_connect_req(dev, cl)) {
			dev_dbg(&dev->pdev->dev, "Sending connect message - failed\n");
			rets = -ENODEV;
			goto end;
		} else {
			dev_dbg(&dev->pdev->dev, "Sending connect message - succeeded\n");
			cl->timer_count = MEI_CONNECT_TIMEOUT;
			list_add_tail(&cb->list, &dev->ctrl_rd_list.list);
		}


	} else {
		dev_dbg(&dev->pdev->dev, "Queuing the connect request due to device busy\n");
		dev_dbg(&dev->pdev->dev, "add connect cb to control write list.\n");
		list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
	}
	mutex_unlock(&dev->device_lock);
	err = wait_event_timeout(dev->wait_recvd_msg,
			(MEI_FILE_CONNECTED == cl->state ||
			 MEI_FILE_DISCONNECTED == cl->state), timeout);

	mutex_lock(&dev->device_lock);
	if (MEI_FILE_CONNECTED == cl->state) {
		dev_dbg(&dev->pdev->dev, "successfully connected to FW client.\n");
		rets = cl->status;
		goto end;
	} else {
		dev_dbg(&dev->pdev->dev, "failed to connect to FW client.cl->state = %d.\n",
		    cl->state);
		if (!err) {
			dev_dbg(&dev->pdev->dev,
				"wait_event_interruptible_timeout failed on client"
				" connect message fw response message.\n");
		}
		rets = -EFAULT;

		mei_io_list_flush(&dev->ctrl_rd_list, cl);
		mei_io_list_flush(&dev->ctrl_wr_list, cl);
		goto end;
	}
	rets = 0;
end:
	dev_dbg(&dev->pdev->dev, "free connect cb memory.");
	mei_io_cb_free(cb);
	return rets;
}

/**
 * mei_start_read - the start read client message function.
 *
 * @dev: the device structure
 * @if_num:  minor number
 * @cl: private data of the file object
 *
 * returns 0 on success, <0 on failure.
 */
int mei_start_read(struct mei_device *dev, struct mei_cl *cl)
{
	struct mei_cl_cb *cb;
	int rets;
	int i;

	if (cl->state != MEI_FILE_CONNECTED)
		return -ENODEV;

	if (dev->dev_state != MEI_DEV_ENABLED)
		return -ENODEV;

	if (cl->read_pending || cl->read_cb) {
		dev_dbg(&dev->pdev->dev, "read is pending.\n");
		return -EBUSY;
	}
	i = mei_me_cl_by_id(dev, cl->me_client_id);
	if (i < 0) {
		dev_err(&dev->pdev->dev, "no such me client %d\n",
			cl->me_client_id);
		return  -ENODEV;
	}

	cb = mei_io_cb_init(cl, NULL);
	if (!cb)
		return -ENOMEM;

	rets = mei_io_cb_alloc_resp_buf(cb,
			dev->me_clients[i].props.max_msg_length);
	if (rets)
		goto err;

	cb->fop_type = MEI_FOP_READ;
	cl->read_cb = cb;
	if (dev->mei_host_buffer_is_empty) {
		dev->mei_host_buffer_is_empty = false;
		if (mei_hbm_cl_flow_control_req(dev, cl)) {
			rets = -ENODEV;
			goto err;
		}
		list_add_tail(&cb->list, &dev->read_list.list);
	} else {
		list_add_tail(&cb->list, &dev->ctrl_wr_list.list);
	}
	return rets;
err:
	mei_io_cb_free(cb);
	return rets;
}