/*
 * imx_mcc_tty.c - pty demo driver used to test imx mcc
 * posix pty interface.
 *
 * Copyright (C) 2014 Freescale Semiconductor, Inc.
 */

/*
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/mcc_common.h>
#include <linux/mcc_api.h>

/**
 * struct mcctty_port - Wrapper struct for imx mcc pty port.
 * @port:		TTY port data
 * @rx_lock:		Lock for rx_buf.
 * @rx_buf:		Read buffer
 */
struct mcctty_port {
	struct delayed_work	read;
	struct tty_port		port;
	spinlock_t		rx_lock;
	char			*rx_buf;
};

static struct mcctty_port mcc_tty_port;

enum {
	MCC_NODE_A9 = 0,
	MCC_NODE_M4 = 0,

	MCC_A9_PORT = 1,
	MCC_M4_PORT = 2,
};

/* mcc tty/pingpong demo */
static MCC_ENDPOINT mcc_endpoint_a9_pingpong = {0, MCC_NODE_A9, MCC_A9_PORT};
static MCC_ENDPOINT mcc_endpoint_m4_pingpong = {1, MCC_NODE_M4, MCC_M4_PORT};
struct mcc_pp_msg {
	unsigned int data;
};

static void mcctty_delay_work(struct work_struct *work)
{
	struct mcctty_port *cport = &mcc_tty_port;
	int ret, space;
	unsigned char *cbuf;
	struct mcc_pp_msg pp_msg;
	MCC_MEM_SIZE num_of_received_bytes;
	MCC_INFO_STRUCT mcc_info;

	/* start mcc tty recv here */
	ret = mcc_initialize(MCC_NODE_A9);
	if (ret)
		pr_err("failed to initialize mcc.\n");

	ret = mcc_get_info(MCC_NODE_A9, &mcc_info);
	if (ret)
		pr_err("failed to get mcc info.\n");
	pr_info("\nA9 mcc prepares run, MCC version is %s\n",
			mcc_info.version_string);

	pr_info("imx mcc tty/pingpong demo begin.\n");
	ret = mcc_create_endpoint(&mcc_endpoint_a9_pingpong,
			MCC_A9_PORT);
	if (ret)
		pr_err("failed to create a9 mcc ep.\n");

	while (1) {
		ret = mcc_recv_copy(&mcc_endpoint_a9_pingpong, &pp_msg,
				sizeof(struct mcc_pp_msg),
				&num_of_received_bytes, 0xffffffff);

		if (MCC_SUCCESS != ret) {
			pr_err("A9 Main task receive error: %d\n", ret);
		} else {
			/* flush the recv-ed data to tty node */
			spin_lock_bh(&cport->rx_lock);
			space = tty_prepare_flip_string(&cport->port, &cbuf,
							num_of_received_bytes);
			if ((space <= 0) || (cport->rx_buf == NULL))
				goto pp_unlock;

			memcpy(cport->rx_buf, &pp_msg.data,
					num_of_received_bytes);
			memcpy(cbuf, cport->rx_buf, space);
			tty_flip_buffer_push(&cport->port);
pp_unlock:
			spin_unlock_bh(&cport->rx_lock);
		}
	}
}

static struct tty_port_operations  mcctty_port_ops = { };

static int mcctty_install(struct tty_driver *driver, struct tty_struct *tty)
{
	return tty_port_install(&mcc_tty_port.port, driver, tty);
}

static int mcctty_open(struct tty_struct *tty, struct file *filp)
{
	return tty_port_open(tty->port, tty, filp);
}

static void mcctty_close(struct tty_struct *tty, struct file *filp)
{
	return tty_port_close(tty->port, tty, filp);
}

static int mcctty_write(struct tty_struct *tty, const unsigned char *buf,
			 int total)
{
	int i, ret = 0;
	struct mcc_pp_msg pp_msg;

	if (NULL == buf)
		return 0;

	for (i = 0; i < total; i++) {
		pp_msg.data = (unsigned int)buf[i];

		/*
		 * wait until the remote endpoint is created by
		 * the other core
		 */
		ret = mcc_send(&mcc_endpoint_m4_pingpong, &pp_msg,
				sizeof(struct mcc_pp_msg),
				0xffffffff);

		while (MCC_ERR_ENDPOINT == ret) {
			pr_err("\n send err ret %d, re-send\n", ret);
			ret = mcc_send(&mcc_endpoint_m4_pingpong, &pp_msg,
					sizeof(struct mcc_pp_msg),
					0xffffffff);
			msleep(5000);
		}
	}

	return total;
}

static int mcctty_write_room(struct tty_struct *tty)
{
	int room;

	/* report the space in the mcc buffer */
	room = MCC_ATTR_BUFFER_SIZE_IN_BYTES;

	return room;
}

static const struct tty_operations imxmcctty_ops = {
	.install		= mcctty_install,
	.open			= mcctty_open,
	.close			= mcctty_close,
	.write			= mcctty_write,
	.write_room		= mcctty_write_room,
};

static struct tty_driver *mcctty_driver;

static int __init imxmcctty_init(void)
{
	int ret;
	struct mcctty_port *cport = &mcc_tty_port;

	mcctty_driver = tty_alloc_driver(1,
			TTY_DRIVER_RESET_TERMIOS |
			TTY_DRIVER_UNNUMBERED_NODE);
	if (IS_ERR(mcctty_driver))
		return PTR_ERR(mcctty_driver);

	mcctty_driver->driver_name = "mcc_tty";
	mcctty_driver->name = "ttyMCC";
	mcctty_driver->major = TTYAUX_MAJOR;
	mcctty_driver->minor_start = 3;
	mcctty_driver->type = TTY_DRIVER_TYPE_PTY;
	mcctty_driver->init_termios = tty_std_termios;
	mcctty_driver->init_termios.c_cflag |= CLOCAL;

	tty_set_operations(mcctty_driver, &imxmcctty_ops);

	tty_port_init(&cport->port);
	cport->port.ops = &mcctty_port_ops;
	spin_lock_init(&cport->rx_lock);

	ret = tty_register_driver(mcctty_driver);
	if (ret < 0) {
		pr_err("Couldn't install mcc tty driver: err %d\n", ret);
		goto error;
	} else
		pr_info("Install mcc tty driver!\n");

	/* Allocate the buffer we use for reading data */
	cport->rx_buf = kzalloc(MCC_ATTR_BUFFER_SIZE_IN_BYTES,
			GFP_KERNEL);
	if (!cport->rx_buf) {
		ret = -ENOMEM;
		goto error;
	}

	INIT_DELAYED_WORK(&cport->read, mcctty_delay_work);
	schedule_delayed_work(&cport->read, HZ/100);
	return 0;

error:
	tty_unregister_driver(mcctty_driver);
	put_tty_driver(mcctty_driver);
	tty_port_destroy(&cport->port);
	mcctty_driver = NULL;

	return ret;
}

static void imxmcctty_exit(void)
{
	int ret = 0;
	struct mcctty_port *cport = &mcc_tty_port;

	/* stop reading, null the read buffer. */
	kfree(cport->rx_buf);
	cport->rx_buf = NULL;

	/* destory the mcc tty endpoint here */
	ret = mcc_destroy_endpoint(&mcc_endpoint_a9_pingpong);
	if (ret)
		pr_err("failed to destory a9 mcc ep.\n");
	else
		pr_info("destory a9 mcc ep.\n");

	tty_unregister_driver(mcctty_driver);
	tty_port_destroy(&cport->port);
	put_tty_driver(mcctty_driver);
}

module_init(imxmcctty_init);
module_exit(imxmcctty_exit);