/*
 *  User Mode Init manager - For TI shared transport
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that 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.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program;if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <string.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <termios.h>
#include <poll.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/utsname.h>

#include "uim.h"

/* Maintains the exit state of UIM*/
static int exiting;

/* UART configuration parameters*/
int uart_flow_control;
int cust_baud_rate;
char uart_dev_name[15];
unsigned int uart_baud_rate;
struct termios ti;
int line_discipline;

/* File descriptor for the UART device*/
int dev_fd;

/* Maintains the state of N_TI_WL line discipline installation*/
unsigned char st_state = INSTALL_N_TI_WL;
unsigned char prev_st_state = UNINSTALL_N_TI_WL;

struct rfkill_event {
uint32_t idx;
uint8_t  type;
uint8_t  op;
uint8_t  soft, hard;
} __packed;
struct rfkill_event rf_event;
int 	rfkill_idx;

/*****************************************************************************/
#ifdef UIM_DEBUG
/*  Function to Read the firmware version
 *  module into the system. Currently used for
 *  debugging purpose, whenever the baud rate is changed
 */
void read_firmware_version()
{
	int index = 0;
	char resp_buffer[20] = { 0 };
	unsigned char buffer[] = { 0x01, 0x01, 0x10, 0x00 };

	UIM_START_FUNC();
	UIM_VER(" wrote %d bytes", (int)write(dev_fd, buffer, 4));
	UIM_VER(" reading %d bytes", (int)read(dev_fd, resp_buffer, 15));

	for (index = 0; index < 15; index++)
		UIM_VER(" %x ", resp_buffer[index]);

	printf("\n");
}
#endif

/*****************************************************************************/
/* Function to read the HCI event from the given file descriptor
 *
 * This will parse the response received and returns error
 * if the required response is not received
 */
int read_hci_event(int fd, unsigned char *buf, int size)
{
	int remain, rd;
	int count = 0;
	int reading = 1;
	int rd_retry_count = 0;
	struct timespec tm = {0, 50*1000*1000};

	UIM_START_FUNC();

	UIM_VER(" read_hci_event");
	if (size <= 0)
		return -1;

	/* The first byte identifies the packet type. For HCI event packets, it
	 * should be 0x04, so we read until we get to the 0x04. */
	while (reading) {
		rd = read(fd, buf, 1);
		if (rd <= 0 && rd_retry_count++ < 4) {
			nanosleep(&tm, NULL);
			continue;
		} else if (rd_retry_count >= 4) {
			return -1;
		}

		if (buf[0] == RESP_PREFIX)
			break;

	}
	count++;

	/* The next two bytes are the event code and parameter total length. */
	while (count < 3) {
		rd = read(fd, buf + count, 3 - count);
		if (rd <= 0)
			return -1;
		count += rd;
	}

	/* Now we read the parameters. */
	if (buf[2] < (size - 3))
		remain = buf[2];
	else
		remain = size - 3;

	while ((count - 3) < remain) {
		rd = read(fd, buf + count, remain - (count - 3));
		if (rd <= 0)
			return -1;
		count += rd;
	}

	return count;
}

/* Function to read the Command complete event
 *
 * This will read the response for the change speed
 * command that was sent to configure the UART speed
 * with the custom baud rate
 */
static int read_command_complete(int fd, unsigned short opcode)
{
	struct command_complete_t resp;

	UIM_START_FUNC();

	UIM_VER(" Command complete started");
	if (read_hci_event(fd, (unsigned char *)&resp, sizeof(resp)) < 0) {
		UIM_ERR(" Invalid response");
		return -1;
	}

	/* Response should be an event packet */
	if (resp.uart_prefix != HCI_EVENT_PKT) {
		UIM_ERR
			(" Error in response: not an event packet, but 0x%02x!",
			 resp.uart_prefix);
		return -1;
	}

	/* Response should be a command complete event */
	if (resp.hci_hdr.evt != EVT_CMD_COMPLETE) {
		/* event must be event-complete */
		UIM_ERR
			(" Error in response: not a cmd-complete event,but 0x%02x!",
			 resp.hci_hdr.evt);
		return -1;
	}

	if (resp.hci_hdr.plen < 4) {
		/* plen >= 4 for EVT_CMD_COMPLETE */
		UIM_ERR(" Error in response: plen is not >= 4, but 0x%02x!",
				resp.hci_hdr.plen);
		return -1;
	}

	if (resp.cmd_complete.opcode != (unsigned short)opcode) {
		UIM_ERR(" Error in response: opcode is 0x%04x, not 0x%04x!",
				resp.cmd_complete.opcode, opcode);
		return -1;
	}

	UIM_DBG(" Command complete done");
	return resp.status == 0 ? 0 : -1;
}

/* Function to set the default baud rate
 *
 * The default baud rate of 115200 is set to the UART from the host side
 * by making a call to this function.This function is also called before
 * making a call to set the custom baud rate
 */
static int set_baud_rate()
{
	UIM_START_FUNC();

	tcflush(dev_fd, TCIOFLUSH);

	/* Get the attributes of UART */
	if (tcgetattr(dev_fd, &ti) < 0) {
		UIM_ERR(" Can't get port settings");
		return -1;
	}

	/* Change the UART attributes before
	 * setting the default baud rate*/
	cfmakeraw(&ti);

	ti.c_cflag |= 1;
	ti.c_cflag |= CRTSCTS;

	/* Set the attributes of UART after making
	 * the above changes
	 */
	tcsetattr(dev_fd, TCSANOW, &ti);

	/* Set the actual default baud rate */
	cfsetospeed(&ti, B115200);
	cfsetispeed(&ti, B115200);
	tcsetattr(dev_fd, TCSANOW, &ti);

	tcflush(dev_fd, TCIOFLUSH);
	UIM_DBG(" set_baud_rate() done");

	return 0;
}

/* Function to set the UART custom baud rate.
 *
 * The UART baud rate has already been
 * set to default value 115200 before calling this function.
 * The baud rate is then changed to custom baud rate by this function*/
static int set_custom_baud_rate()
{
	UIM_START_FUNC();

	struct termios2 ti2;

	UIM_VER(" Changing baud rate to %u, flow control to %u",
			cust_baud_rate, uart_flow_control);

	/* Flush non-transmitted output data,
	 * non-read input data or both*/
	tcflush(dev_fd, TCIOFLUSH);

	/*Set the UART flow control */
	if (uart_flow_control)
		ti.c_cflag |= CRTSCTS;
	else
		ti.c_cflag &= ~CRTSCTS;

	/*
	 * Set the parameters associated with the UART
	 * The change will occur immediately by using TCSANOW
	 */
	if (tcsetattr(dev_fd, TCSANOW, &ti) < 0) {
		UIM_ERR(" Can't set port settings");
		return -1;
	}

	tcflush(dev_fd, TCIOFLUSH);

	/*Set the actual baud rate */
	ioctl(dev_fd, TCGETS2, &ti2);
	ti2.c_cflag &= ~CBAUD;
	ti2.c_cflag |= BOTHER;
	ti2.c_ospeed = cust_baud_rate;
	ioctl(dev_fd, TCSETS2, &ti2);

	UIM_DBG(" set_custom_baud_rate() done");
	return 0;
}

/*
 * After receiving the indication from rfkill subsystem, configure the
 * baud rate, flow control and Install the N_TI_WL line discipline
 */
int st_uart_config()
{
	int ldisc, len;
	struct uim_speed_change_cmd cmd;

	UIM_START_FUNC();

	/* Install the line discipline when the rfkill signal is received by UIM.
	 * Whenever the first protocol tries to register with the ST core, the
	 * ST KIM will inform the UIM through rfkill subsystem to install the N_TI_WL
	 * line discipline and do the host side UART configurations.
	 *
	 * On failure, ST KIM's line discipline installation times out, and the
	 * relevant protocol register fails
	 */
	if (st_state == INSTALL_N_TI_WL) {
		UIM_VER(" signal received, opening %s", uart_dev_name);
		dev_fd = open(uart_dev_name, O_RDWR);
		if (dev_fd < 0) {
			UIM_ERR(" Can't open %s", uart_dev_name);
			return -1;
		}
		/*
		 * Set only the default baud rate.
		 * This will set the baud rate to default 115200
		 */
		if (set_baud_rate() < 0) {
			UIM_ERR(" set_baudrate() failed");
			close(dev_fd);
			return -1;
		}

		fcntl(dev_fd, F_SETFL,fcntl(dev_fd, F_GETFL) | O_NONBLOCK);
		/* Set only thecustom baud rate */
		if (cust_baud_rate) {

			/* Forming the packet for Change speed command */
			cmd.uart_prefix = HCI_COMMAND_PKT;
			cmd.hci_hdr.opcode = HCI_HDR_OPCODE;
			cmd.hci_hdr.plen = sizeof(unsigned long);
			cmd.speed = cust_baud_rate;

			/* Writing the change speed command to the UART
			 * This will change the UART speed at the controller
			 * side
			 */
			UIM_VER(" Setting speed to %d", cust_baud_rate);
			len = write(dev_fd, &cmd, sizeof(cmd));
			if (len < 0) {
				UIM_ERR(" Failed to write speed-set command");
				close(dev_fd);
				return -1;
			}

			/* Read the response for the Change speed command */
			if (read_command_complete(dev_fd, HCI_HDR_OPCODE) < 0) {
				close(dev_fd);
				return -1;
			}

			UIM_VER(" Speed changed to %d", cust_baud_rate);

			/* Set the actual custom baud rate at the host side */
			if (set_custom_baud_rate() < 0) {
				UIM_ERR(" set_custom_baud_rate() failed");
				close(dev_fd);

				return -1;
			}
#ifdef UIM_DEBUG
			read_firmware_version();
#endif
		}

		/* After the UART speed has been changed, the IOCTL is
		 * is called to set the line discipline to N_TI_WL
		 */
		ldisc = line_discipline;
		if (ioctl(dev_fd, TIOCSETD, &ldisc) < 0) {
			UIM_ERR(" Can't set line discipline");
			close(dev_fd);
			return -1;
		}

		UIM_DBG(" Installed N_TI_WL Line displine");
	} else {
		/* UNINSTALL_N_TI_WL - When the Signal is received from KIM */
		/* closing UART fd */
		UIM_DBG(" Uninstalled N_TI_WL Line displine");
		close(dev_fd);
	}
	prev_st_state = st_state;
	return 0;
}
int remove_modules()
{
	int err = 0;

	UIM_VER(" Removing bt_drv ");
	if (system("rmmod bt_drv") != 0) {
		UIM_ERR(" Error removing bt_drv module");
		err = -1;
	} else {
		UIM_DBG(" Removed bt_drv module");
	}

	/*Remove the Shared Transport */
	UIM_VER(" Removing st_drv ");

	if (system("rmmod st_drv") != 0) {
		UIM_ERR(" Error removing st_drv module");
		err = -1;
	} else {
		UIM_DBG(" Removed st_drv module ");
	}

	return err;
}

int change_rfkill_perms(void)
{
	int fd, id, sz;
	char path[64];
	char buf[16];
	for (id = 0; id < 50; id++) {
		snprintf(path, sizeof(path),
			"/sys/class/rfkill/rfkill%d/type", id);
		fd = open(path, O_RDONLY);
		if (fd < 0) {
			UIM_DBG("open(%s) failed: %s (%d)\n",
				path, strerror(errno), errno);
			continue;
		}
		sz = read(fd, &buf, sizeof(buf));
		close(fd);
		if (sz >= 9 && memcmp(buf, "bluetooth", 9) == 0) {
			UIM_DBG("found bluetooth rfkill entry @ %d\n", id);
			rfkill_idx = id;
			break;
		}
	}
	if (id == 50)
		return -1;

	sz = chmod(path, 0660);
	if (sz < 0) {
		UIM_ERR("change mode failed for %s (%d)\n", path, errno);
		return -1;
	}
	UIM_DBG("changed permissions for %s(%d) \n", path, sz);
	/* end of change_perms */

	return 0;
}
/*****************************************************************************/
int main(int argc, char *argv[])
{
	int st_fd, err;
	char buf[20] = { 0 };
	struct sigaction sa;
	struct stat file_stat;
	struct utsname name;

	struct pollfd p;
	sigset_t sigs;

	UIM_START_FUNC();
	err = 0;

	/* Parse the user input */
	if (argc == 5) {
		strcpy(uart_dev_name, argv[1]);
		uart_baud_rate = atoi(argv[2]);
		uart_flow_control = atoi(argv[3]);
		line_discipline = atoi(argv[4]);

		/* Depending upon the baud rate value, differentiate
		 * the custom baud rate and default baud rate
		 */
		switch (uart_baud_rate) {
			case 115200:
				UIM_VER(" Baudrate 115200");
				break;
			case 9600:
			case 19200:
			case 38400:
			case 57600:
			case 230400:
			case 460800:
			case 500000:
			case 576000:
			case 921600:
			case 1000000:
			case 1152000:
			case 1500000:
			case 2000000:
			case 2500000:
			case 3000000:
			case 3500000:
			case 3686400:
			case 4000000:
				cust_baud_rate = uart_baud_rate;
				UIM_VER(" Baudrate %d", cust_baud_rate);
				break;
			default:
				UIM_ERR(" Inavalid Baud Rate");
				break;
		}
	} else {
		UIM_ERR(" Invalid arguements");
		UIM_ERR(" Usage: uim [Uart device] [Baud rate] [Flow control] [Line discipline]");
		return -1;
	}

	if (uname (&name) == -1) {
	   UIM_ERR("cannot get kernel release name");
	   return -1;
	}

	st_fd = open("/dev/rfkill", O_RDONLY);

	p.fd = st_fd;
	p.events = POLLERR | POLLHUP | POLLOUT | POLLIN;

	sigfillset(&sigs);
	sigdelset(&sigs, SIGCHLD);
	sigdelset(&sigs, SIGPIPE);
	sigdelset(&sigs, SIGTERM);
	sigdelset(&sigs, SIGINT);
	sigdelset(&sigs, SIGHUP);

RE_POLL:
	while (!exiting) {
		p.revents = 0;
		err = ppoll(&p, 1, NULL, &sigs);
		if (err < 0 && errno == EINTR)
			continue;
		if (err)
			break;
	}
	if (!exiting) {
		err = read(st_fd, &rf_event, sizeof(rf_event));
		UIM_DBG("rf_event: idx %d, type %d, op %d, hard %d, soft %d with rfkill_idx=%d and state:%d\n", rf_event.idx,
			rf_event.type, rf_event.op , rf_event.hard,
			rf_event.soft, rfkill_idx, st_state);
		if ((rf_event.op == 2) /*&&
			(rf_event.idx == rfkill_idx)*/) {
			if (rf_event.hard == 1) {
				st_state = UNINSTALL_N_TI_WL;
				UIM_DBG("UNINSTALL_N_TI_WL");
			} else {
				st_state = INSTALL_N_TI_WL;
				UIM_DBG("INSTALL_N_TI_WL");
			}
			if (prev_st_state != st_state)
				st_uart_config();
		}
		goto RE_POLL;
	}

	if (remove_modules() < 0) {
		UIM_ERR(" Error removing modules ");
		close(st_fd);
		return -1;
	}

	close(st_fd);
	return 0;
}