1 files changed, 1082 insertions, 0 deletions
diff --git a/greybus_uart.patch b/greybus_uart.patch
new file mode 100644
index 00000000000000..6cbecc463c130e
--- /dev/null
+++ b/greybus_uart.patch
@@ -0,0 +1,1082 @@
+---
+ drivers/greybus/uart.c | 1075 +++++++++++++++++++++++++++++++++++++++++++++++++
+ 1 file changed, 1075 insertions(+)
+
+--- /dev/null
++++ b/drivers/greybus/uart.c
+@@ -0,0 +1,1075 @@
++/*
++ * UART driver for the Greybus "generic" UART module.
++ *
++ * Copyright 2014 Google Inc.
++ * Copyright 2014 Linaro Ltd.
++ *
++ * Released under the GPLv2 only.
++ *
++ * Heavily based on drivers/usb/class/cdc-acm.c and
++ * drivers/usb/serial/usb-serial.c.
++ */
++#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
++
++#include <linux/kernel.h>
++#include <linux/errno.h>
++#include <linux/module.h>
++#include <linux/sched.h>
++#include <linux/wait.h>
++#include <linux/slab.h>
++#include <linux/uaccess.h>
++#include <linux/mutex.h>
++#include <linux/tty.h>
++#include <linux/serial.h>
++#include <linux/tty_driver.h>
++#include <linux/tty_flip.h>
++#include <linux/serial.h>
++#include <linux/idr.h>
++#include <linux/fs.h>
++#include <linux/kdev_t.h>
++#include <linux/kfifo.h>
++#include <linux/workqueue.h>
++#include <linux/completion.h>
++
++#include "greybus.h"
++#include "gbphy.h"
++
++#define GB_NUM_MINORS	16	/* 16 is is more than enough */
++#define GB_NAME		"ttyGB"
++
++#define GB_UART_WRITE_FIFO_SIZE		PAGE_SIZE
++#define GB_UART_WRITE_ROOM_MARGIN	1	/* leave some space in fifo */
++#define GB_UART_FIRMWARE_CREDITS	4096
++#define GB_UART_CREDIT_WAIT_TIMEOUT_MSEC	10000
++
++struct gb_tty_line_coding {
++	__le32	rate;
++	__u8	format;
++	__u8	parity;
++	__u8	data_bits;
++	__u8	flow_control;
++};
++
++struct gb_tty {
++	struct gbphy_device *gbphy_dev;
++	struct tty_port port;
++	void *buffer;
++	size_t buffer_payload_max;
++	struct gb_connection *connection;
++	u16 cport_id;
++	unsigned int minor;
++	unsigned char clocal;
++	bool disconnected;
++	spinlock_t read_lock;
++	spinlock_t write_lock;
++	struct async_icount iocount;
++	struct async_icount oldcount;
++	wait_queue_head_t wioctl;
++	struct mutex mutex;
++	u8 ctrlin;	/* input control lines */
++	u8 ctrlout;	/* output control lines */
++	struct gb_tty_line_coding line_coding;
++	struct work_struct tx_work;
++	struct kfifo write_fifo;
++	bool close_pending;
++	unsigned int credits;
++	struct completion credits_complete;
++};
++
++static struct tty_driver *gb_tty_driver;
++static DEFINE_IDR(tty_minors);
++static DEFINE_MUTEX(table_lock);
++
++static int gb_uart_receive_data_handler(struct gb_operation *op)
++{
++	struct gb_connection *connection = op->connection;
++	struct gb_tty *gb_tty = gb_connection_get_data(connection);
++	struct tty_port *port = &gb_tty->port;
++	struct gb_message *request = op->request;
++	struct gb_uart_recv_data_request *receive_data;
++	u16 recv_data_size;
++	int count;
++	unsigned long tty_flags = TTY_NORMAL;
++
++	if (request->payload_size < sizeof(*receive_data)) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++				"short receive-data request received (%zu < %zu)\n",
++				request->payload_size, sizeof(*receive_data));
++		return -EINVAL;
++	}
++
++	receive_data = op->request->payload;
++	recv_data_size = le16_to_cpu(receive_data->size);
++
++	if (recv_data_size != request->payload_size - sizeof(*receive_data)) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++				"malformed receive-data request received (%u != %zu)\n",
++				recv_data_size,
++				request->payload_size - sizeof(*receive_data));
++		return -EINVAL;
++	}
++
++	if (!recv_data_size)
++		return -EINVAL;
++
++	if (receive_data->flags) {
++		if (receive_data->flags & GB_UART_RECV_FLAG_BREAK)
++			tty_flags = TTY_BREAK;
++		else if (receive_data->flags & GB_UART_RECV_FLAG_PARITY)
++			tty_flags = TTY_PARITY;
++		else if (receive_data->flags & GB_UART_RECV_FLAG_FRAMING)
++			tty_flags = TTY_FRAME;
++
++		/* overrun is special, not associated with a char */
++		if (receive_data->flags & GB_UART_RECV_FLAG_OVERRUN)
++			tty_insert_flip_char(port, 0, TTY_OVERRUN);
++	}
++	count = tty_insert_flip_string_fixed_flag(port, receive_data->data,
++						  tty_flags, recv_data_size);
++	if (count != recv_data_size) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++			"UART: RX 0x%08x bytes only wrote 0x%08x\n",
++			recv_data_size, count);
++	}
++	if (count)
++		tty_flip_buffer_push(port);
++	return 0;
++}
++
++static int gb_uart_serial_state_handler(struct gb_operation *op)
++{
++	struct gb_connection *connection = op->connection;
++	struct gb_tty *gb_tty = gb_connection_get_data(connection);
++	struct gb_message *request = op->request;
++	struct gb_uart_serial_state_request *serial_state;
++
++	if (request->payload_size < sizeof(*serial_state)) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++				"short serial-state event received (%zu < %zu)\n",
++				request->payload_size, sizeof(*serial_state));
++		return -EINVAL;
++	}
++
++	serial_state = request->payload;
++	gb_tty->ctrlin = serial_state->control;
++
++	return 0;
++}
++
++static int gb_uart_receive_credits_handler(struct gb_operation *op)
++{
++	struct gb_connection *connection = op->connection;
++	struct gb_tty *gb_tty = gb_connection_get_data(connection);
++	struct gb_message *request = op->request;
++	struct gb_uart_receive_credits_request *credit_request;
++	unsigned long flags;
++	unsigned int incoming_credits;
++	int ret = 0;
++
++	if (request->payload_size < sizeof(*credit_request)) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++				"short receive_credits event received (%zu < %zu)\n",
++				request->payload_size,
++				sizeof(*credit_request));
++		return -EINVAL;
++	}
++
++	credit_request = request->payload;
++	incoming_credits = le16_to_cpu(credit_request->count);
++
++	spin_lock_irqsave(&gb_tty->write_lock, flags);
++	gb_tty->credits += incoming_credits;
++	if (gb_tty->credits > GB_UART_FIRMWARE_CREDITS) {
++		gb_tty->credits -= incoming_credits;
++		ret = -EINVAL;
++	}
++	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++
++	if (ret) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++			"invalid number of incoming credits: %d\n",
++			incoming_credits);
++		return ret;
++	}
++
++	if (!gb_tty->close_pending)
++		schedule_work(&gb_tty->tx_work);
++
++	/*
++	 * the port the tty layer may be waiting for credits
++	 */
++	tty_port_tty_wakeup(&gb_tty->port);
++
++	if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
++		complete(&gb_tty->credits_complete);
++
++	return ret;
++}
++
++static int gb_uart_request_handler(struct gb_operation *op)
++{
++	struct gb_connection *connection = op->connection;
++	struct gb_tty *gb_tty = gb_connection_get_data(connection);
++	int type = op->type;
++	int ret;
++
++	switch (type) {
++	case GB_UART_TYPE_RECEIVE_DATA:
++		ret = gb_uart_receive_data_handler(op);
++		break;
++	case GB_UART_TYPE_SERIAL_STATE:
++		ret = gb_uart_serial_state_handler(op);
++		break;
++	case GB_UART_TYPE_RECEIVE_CREDITS:
++		ret = gb_uart_receive_credits_handler(op);
++		break;
++	default:
++		dev_err(&gb_tty->gbphy_dev->dev,
++			"unsupported unsolicited request: 0x%02x\n", type);
++		ret = -EINVAL;
++	}
++
++	return ret;
++}
++
++static void  gb_uart_tx_write_work(struct work_struct *work)
++{
++	struct gb_uart_send_data_request *request;
++	struct gb_tty *gb_tty;
++	unsigned long flags;
++	unsigned int send_size;
++	int ret;
++
++	gb_tty = container_of(work, struct gb_tty, tx_work);
++	request = gb_tty->buffer;
++
++	while (1) {
++		if (gb_tty->close_pending)
++			break;
++
++		spin_lock_irqsave(&gb_tty->write_lock, flags);
++		send_size = gb_tty->buffer_payload_max;
++		if (send_size > gb_tty->credits)
++			send_size = gb_tty->credits;
++
++		send_size = kfifo_out_peek(&gb_tty->write_fifo,
++					&request->data[0],
++					send_size);
++		if (!send_size) {
++			spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++			break;
++		}
++
++		gb_tty->credits -= send_size;
++		spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++
++		request->size = cpu_to_le16(send_size);
++		ret = gb_operation_sync(gb_tty->connection,
++					GB_UART_TYPE_SEND_DATA,
++					request, sizeof(*request) + send_size,
++					NULL, 0);
++		if (ret) {
++			dev_err(&gb_tty->gbphy_dev->dev,
++				"send data error: %d\n", ret);
++			spin_lock_irqsave(&gb_tty->write_lock, flags);
++			gb_tty->credits += send_size;
++			spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++			if (!gb_tty->close_pending)
++				schedule_work(work);
++			return;
++		}
++
++		spin_lock_irqsave(&gb_tty->write_lock, flags);
++		ret = kfifo_out(&gb_tty->write_fifo, &request->data[0],
++				send_size);
++		spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++
++		tty_port_tty_wakeup(&gb_tty->port);
++	}
++}
++
++static int send_line_coding(struct gb_tty *tty)
++{
++	struct gb_uart_set_line_coding_request request;
++
++	memcpy(&request, &tty->line_coding,
++	       sizeof(tty->line_coding));
++	return gb_operation_sync(tty->connection, GB_UART_TYPE_SET_LINE_CODING,
++				 &request, sizeof(request), NULL, 0);
++}
++
++static int send_control(struct gb_tty *gb_tty, u8 control)
++{
++	struct gb_uart_set_control_line_state_request request;
++
++	request.control = control;
++	return gb_operation_sync(gb_tty->connection,
++				 GB_UART_TYPE_SET_CONTROL_LINE_STATE,
++				 &request, sizeof(request), NULL, 0);
++}
++
++static int send_break(struct gb_tty *gb_tty, u8 state)
++{
++	struct gb_uart_set_break_request request;
++
++	if ((state != 0) && (state != 1)) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++			"invalid break state of %d\n", state);
++		return -EINVAL;
++	}
++
++	request.state = state;
++	return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_SEND_BREAK,
++				 &request, sizeof(request), NULL, 0);
++}
++
++static int gb_uart_wait_for_all_credits(struct gb_tty *gb_tty)
++{
++	int ret;
++
++	if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
++		return 0;
++
++	ret = wait_for_completion_timeout(&gb_tty->credits_complete,
++			msecs_to_jiffies(GB_UART_CREDIT_WAIT_TIMEOUT_MSEC));
++	if (!ret) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++			"time out waiting for credits\n");
++		return -ETIMEDOUT;
++	}
++
++	return 0;
++}
++
++static int gb_uart_flush(struct gb_tty *gb_tty, u8 flags)
++{
++	struct gb_uart_serial_flush_request request;
++
++	request.flags = flags;
++	return gb_operation_sync(gb_tty->connection, GB_UART_TYPE_FLUSH_FIFOS,
++				 &request, sizeof(request), NULL, 0);
++}
++
++static struct gb_tty *get_gb_by_minor(unsigned minor)
++{
++	struct gb_tty *gb_tty;
++
++	mutex_lock(&table_lock);
++	gb_tty = idr_find(&tty_minors, minor);
++	if (gb_tty) {
++		mutex_lock(&gb_tty->mutex);
++		if (gb_tty->disconnected) {
++			mutex_unlock(&gb_tty->mutex);
++			gb_tty = NULL;
++		} else {
++			tty_port_get(&gb_tty->port);
++			mutex_unlock(&gb_tty->mutex);
++		}
++	}
++	mutex_unlock(&table_lock);
++	return gb_tty;
++}
++
++static int alloc_minor(struct gb_tty *gb_tty)
++{
++	int minor;
++
++	mutex_lock(&table_lock);
++	minor = idr_alloc(&tty_minors, gb_tty, 0, GB_NUM_MINORS, GFP_KERNEL);
++	mutex_unlock(&table_lock);
++	if (minor >= 0)
++		gb_tty->minor = minor;
++	return minor;
++}
++
++static void release_minor(struct gb_tty *gb_tty)
++{
++	int minor = gb_tty->minor;
++
++	gb_tty->minor = 0;	/* Maybe should use an invalid value instead */
++	mutex_lock(&table_lock);
++	idr_remove(&tty_minors, minor);
++	mutex_unlock(&table_lock);
++}
++
++static int gb_tty_install(struct tty_driver *driver, struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty;
++	int retval;
++
++	gb_tty = get_gb_by_minor(tty->index);
++	if (!gb_tty)
++		return -ENODEV;
++
++	retval = tty_standard_install(driver, tty);
++	if (retval)
++		goto error;
++
++	tty->driver_data = gb_tty;
++	return 0;
++error:
++	tty_port_put(&gb_tty->port);
++	return retval;
++}
++
++static int gb_tty_open(struct tty_struct *tty, struct file *file)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	return tty_port_open(&gb_tty->port, tty, file);
++}
++
++static void gb_tty_close(struct tty_struct *tty, struct file *file)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	tty_port_close(&gb_tty->port, tty, file);
++}
++
++static void gb_tty_cleanup(struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	tty_port_put(&gb_tty->port);
++}
++
++static void gb_tty_hangup(struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	tty_port_hangup(&gb_tty->port);
++}
++
++static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
++			int count)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	count =  kfifo_in_spinlocked(&gb_tty->write_fifo, buf, count,
++					&gb_tty->write_lock);
++	if (count && !gb_tty->close_pending)
++		schedule_work(&gb_tty->tx_work);
++
++	return count;
++}
++
++static int gb_tty_write_room(struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++	unsigned long flags;
++	int room;
++
++	spin_lock_irqsave(&gb_tty->write_lock, flags);
++	room = kfifo_avail(&gb_tty->write_fifo);
++	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++
++	room -= GB_UART_WRITE_ROOM_MARGIN;
++	if (room < 0)
++		return 0;
++
++	return room;
++}
++
++static int gb_tty_chars_in_buffer(struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++	unsigned long flags;
++	int chars;
++
++	spin_lock_irqsave(&gb_tty->write_lock, flags);
++	chars = kfifo_len(&gb_tty->write_fifo);
++	if (gb_tty->credits < GB_UART_FIRMWARE_CREDITS)
++		chars += GB_UART_FIRMWARE_CREDITS - gb_tty->credits;
++	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++
++	return chars;
++}
++
++static int gb_tty_break_ctl(struct tty_struct *tty, int state)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	return send_break(gb_tty, state ? 1 : 0);
++}
++
++static void gb_tty_set_termios(struct tty_struct *tty,
++			       struct ktermios *termios_old)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++	struct ktermios *termios = &tty->termios;
++	struct gb_tty_line_coding newline;
++	u8 newctrl = gb_tty->ctrlout;
++
++	newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
++	newline.format = termios->c_cflag & CSTOPB ?
++				GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
++	newline.parity = termios->c_cflag & PARENB ?
++				(termios->c_cflag & PARODD ? 1 : 2) +
++				(termios->c_cflag & CMSPAR ? 2 : 0) : 0;
++
++	switch (termios->c_cflag & CSIZE) {
++	case CS5:
++		newline.data_bits = 5;
++		break;
++	case CS6:
++		newline.data_bits = 6;
++		break;
++	case CS7:
++		newline.data_bits = 7;
++		break;
++	case CS8:
++	default:
++		newline.data_bits = 8;
++		break;
++	}
++
++	/* FIXME: needs to clear unsupported bits in the termios */
++	gb_tty->clocal = ((termios->c_cflag & CLOCAL) != 0);
++
++	if (C_BAUD(tty) == B0) {
++		newline.rate = gb_tty->line_coding.rate;
++		newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
++	} else if (termios_old && (termios_old->c_cflag & CBAUD) == B0) {
++		newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
++	}
++
++	if (newctrl != gb_tty->ctrlout) {
++		gb_tty->ctrlout = newctrl;
++		send_control(gb_tty, newctrl);
++	}
++
++	if (C_CRTSCTS(tty) && C_BAUD(tty) != B0)
++		newline.flow_control |= GB_SERIAL_AUTO_RTSCTS_EN;
++	else
++		newline.flow_control &= ~GB_SERIAL_AUTO_RTSCTS_EN;
++
++	if (memcmp(&gb_tty->line_coding, &newline, sizeof(newline))) {
++		memcpy(&gb_tty->line_coding, &newline, sizeof(newline));
++		send_line_coding(gb_tty);
++	}
++}
++
++static int gb_tty_tiocmget(struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	return (gb_tty->ctrlout & GB_UART_CTRL_DTR ? TIOCM_DTR : 0) |
++	       (gb_tty->ctrlout & GB_UART_CTRL_RTS ? TIOCM_RTS : 0) |
++	       (gb_tty->ctrlin  & GB_UART_CTRL_DSR ? TIOCM_DSR : 0) |
++	       (gb_tty->ctrlin  & GB_UART_CTRL_RI  ? TIOCM_RI  : 0) |
++	       (gb_tty->ctrlin  & GB_UART_CTRL_DCD ? TIOCM_CD  : 0) |
++	       TIOCM_CTS;
++}
++
++static int gb_tty_tiocmset(struct tty_struct *tty, unsigned int set,
++			   unsigned int clear)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++	u8 newctrl = gb_tty->ctrlout;
++
++	set = (set & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
++	      (set & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
++	clear = (clear & TIOCM_DTR ? GB_UART_CTRL_DTR : 0) |
++		(clear & TIOCM_RTS ? GB_UART_CTRL_RTS : 0);
++
++	newctrl = (newctrl & ~clear) | set;
++	if (gb_tty->ctrlout == newctrl)
++		return 0;
++
++	gb_tty->ctrlout = newctrl;
++	return send_control(gb_tty, newctrl);
++}
++
++static void gb_tty_throttle(struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++	unsigned char stop_char;
++	int retval;
++
++	if (I_IXOFF(tty)) {
++		stop_char = STOP_CHAR(tty);
++		retval = gb_tty_write(tty, &stop_char, 1);
++		if (retval <= 0)
++			return;
++	}
++
++	if (tty->termios.c_cflag & CRTSCTS) {
++		gb_tty->ctrlout &= ~GB_UART_CTRL_RTS;
++		retval = send_control(gb_tty, gb_tty->ctrlout);
++	}
++}
++
++static void gb_tty_unthrottle(struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++	unsigned char start_char;
++	int retval;
++
++	if (I_IXOFF(tty)) {
++		start_char = START_CHAR(tty);
++		retval = gb_tty_write(tty, &start_char, 1);
++		if (retval <= 0)
++			return;
++	}
++
++	if (tty->termios.c_cflag & CRTSCTS) {
++		gb_tty->ctrlout |= GB_UART_CTRL_RTS;
++		retval = send_control(gb_tty, gb_tty->ctrlout);
++	}
++}
++
++static int get_serial_info(struct gb_tty *gb_tty,
++			   struct serial_struct __user *info)
++{
++	struct serial_struct tmp;
++
++	if (!info)
++		return -EINVAL;
++
++	memset(&tmp, 0, sizeof(tmp));
++	tmp.flags = ASYNC_LOW_LATENCY | ASYNC_SKIP_TEST;
++	tmp.type = PORT_16550A;
++	tmp.line = gb_tty->minor;
++	tmp.xmit_fifo_size = 16;
++	tmp.baud_base = 9600;
++	tmp.close_delay = gb_tty->port.close_delay / 10;
++	tmp.closing_wait = gb_tty->port.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
++				ASYNC_CLOSING_WAIT_NONE : gb_tty->port.closing_wait / 10;
++
++	if (copy_to_user(info, &tmp, sizeof(tmp)))
++		return -EFAULT;
++	return 0;
++}
++
++static int set_serial_info(struct gb_tty *gb_tty,
++			   struct serial_struct __user *newinfo)
++{
++	struct serial_struct new_serial;
++	unsigned int closing_wait;
++	unsigned int close_delay;
++	int retval = 0;
++
++	if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
++		return -EFAULT;
++
++	close_delay = new_serial.close_delay * 10;
++	closing_wait = new_serial.closing_wait == ASYNC_CLOSING_WAIT_NONE ?
++			ASYNC_CLOSING_WAIT_NONE : new_serial.closing_wait * 10;
++
++	mutex_lock(&gb_tty->port.mutex);
++	if (!capable(CAP_SYS_ADMIN)) {
++		if ((close_delay != gb_tty->port.close_delay) ||
++		    (closing_wait != gb_tty->port.closing_wait))
++			retval = -EPERM;
++		else
++			retval = -EOPNOTSUPP;
++	} else {
++		gb_tty->port.close_delay = close_delay;
++		gb_tty->port.closing_wait = closing_wait;
++	}
++	mutex_unlock(&gb_tty->port.mutex);
++	return retval;
++}
++
++static int wait_serial_change(struct gb_tty *gb_tty, unsigned long arg)
++{
++	int retval = 0;
++	DECLARE_WAITQUEUE(wait, current);
++	struct async_icount old;
++	struct async_icount new;
++
++	if (!(arg & (TIOCM_DSR | TIOCM_RI | TIOCM_CD)))
++		return -EINVAL;
++
++	do {
++		spin_lock_irq(&gb_tty->read_lock);
++		old = gb_tty->oldcount;
++		new = gb_tty->iocount;
++		gb_tty->oldcount = new;
++		spin_unlock_irq(&gb_tty->read_lock);
++
++		if ((arg & TIOCM_DSR) && (old.dsr != new.dsr))
++			break;
++		if ((arg & TIOCM_CD) && (old.dcd != new.dcd))
++			break;
++		if ((arg & TIOCM_RI) && (old.rng != new.rng))
++			break;
++
++		add_wait_queue(&gb_tty->wioctl, &wait);
++		set_current_state(TASK_INTERRUPTIBLE);
++		schedule();
++		remove_wait_queue(&gb_tty->wioctl, &wait);
++		if (gb_tty->disconnected) {
++			if (arg & TIOCM_CD)
++				break;
++			retval = -ENODEV;
++		} else if (signal_pending(current)) {
++			retval = -ERESTARTSYS;
++		}
++	} while (!retval);
++
++	return retval;
++}
++
++static int get_serial_usage(struct gb_tty *gb_tty,
++			    struct serial_icounter_struct __user *count)
++{
++	struct serial_icounter_struct icount;
++	int retval = 0;
++
++	memset(&icount, 0, sizeof(icount));
++	icount.dsr = gb_tty->iocount.dsr;
++	icount.rng = gb_tty->iocount.rng;
++	icount.dcd = gb_tty->iocount.dcd;
++	icount.frame = gb_tty->iocount.frame;
++	icount.overrun = gb_tty->iocount.overrun;
++	icount.parity = gb_tty->iocount.parity;
++	icount.brk = gb_tty->iocount.brk;
++
++	if (copy_to_user(count, &icount, sizeof(icount)) > 0)
++		retval = -EFAULT;
++
++	return retval;
++}
++
++static int gb_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
++			unsigned long arg)
++{
++	struct gb_tty *gb_tty = tty->driver_data;
++
++	switch (cmd) {
++	case TIOCGSERIAL:
++		return get_serial_info(gb_tty,
++				       (struct serial_struct __user *)arg);
++	case TIOCSSERIAL:
++		return set_serial_info(gb_tty,
++				       (struct serial_struct __user *)arg);
++	case TIOCMIWAIT:
++		return wait_serial_change(gb_tty, arg);
++	case TIOCGICOUNT:
++		return get_serial_usage(gb_tty,
++					(struct serial_icounter_struct __user *)arg);
++	}
++
++	return -ENOIOCTLCMD;
++}
++
++static void gb_tty_dtr_rts(struct tty_port *port, int on)
++{
++	struct gb_tty *gb_tty;
++	u8 newctrl;
++
++	gb_tty = container_of(port, struct gb_tty, port);
++	newctrl = gb_tty->ctrlout;
++
++	if (on)
++		newctrl |= (GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
++	else
++		newctrl &= ~(GB_UART_CTRL_DTR | GB_UART_CTRL_RTS);
++
++	gb_tty->ctrlout = newctrl;
++	send_control(gb_tty, newctrl);
++}
++
++static int gb_tty_port_activate(struct tty_port *port,
++				struct tty_struct *tty)
++{
++	struct gb_tty *gb_tty;
++
++	gb_tty = container_of(port, struct gb_tty, port);
++
++	return gbphy_runtime_get_sync(gb_tty->gbphy_dev);
++}
++
++static void gb_tty_port_shutdown(struct tty_port *port)
++{
++	struct gb_tty *gb_tty;
++	unsigned long flags;
++	int ret;
++
++	gb_tty = container_of(port, struct gb_tty, port);
++
++	gb_tty->close_pending = true;
++
++	cancel_work_sync(&gb_tty->tx_work);
++
++	spin_lock_irqsave(&gb_tty->write_lock, flags);
++	kfifo_reset_out(&gb_tty->write_fifo);
++	spin_unlock_irqrestore(&gb_tty->write_lock, flags);
++
++	if (gb_tty->credits == GB_UART_FIRMWARE_CREDITS)
++		goto out;
++
++	ret = gb_uart_flush(gb_tty, GB_SERIAL_FLAG_FLUSH_TRANSMITTER);
++	if (ret) {
++		dev_err(&gb_tty->gbphy_dev->dev,
++			"error flushing transmitter: %d\n", ret);
++	}
++
++	gb_uart_wait_for_all_credits(gb_tty);
++
++out:
++	gb_tty->close_pending = false;
++
++	gbphy_runtime_put_autosuspend(gb_tty->gbphy_dev);
++}
++
++static const struct tty_operations gb_ops = {
++	.install =		gb_tty_install,
++	.open =			gb_tty_open,
++	.close =		gb_tty_close,
++	.cleanup =		gb_tty_cleanup,
++	.hangup =		gb_tty_hangup,
++	.write =		gb_tty_write,
++	.write_room =		gb_tty_write_room,
++	.ioctl =		gb_tty_ioctl,
++	.throttle =		gb_tty_throttle,
++	.unthrottle =		gb_tty_unthrottle,
++	.chars_in_buffer =	gb_tty_chars_in_buffer,
++	.break_ctl =		gb_tty_break_ctl,
++	.set_termios =		gb_tty_set_termios,
++	.tiocmget =		gb_tty_tiocmget,
++	.tiocmset =		gb_tty_tiocmset,
++};
++
++static struct tty_port_operations gb_port_ops = {
++	.dtr_rts =		gb_tty_dtr_rts,
++	.activate =		gb_tty_port_activate,
++	.shutdown =		gb_tty_port_shutdown,
++};
++
++static int gb_uart_probe(struct gbphy_device *gbphy_dev,
++			 const struct gbphy_device_id *id)
++{
++	struct gb_connection *connection;
++	size_t max_payload;
++	struct gb_tty *gb_tty;
++	struct device *tty_dev;
++	int retval;
++	int minor;
++
++	gb_tty = kzalloc(sizeof(*gb_tty), GFP_KERNEL);
++	if (!gb_tty)
++		return -ENOMEM;
++
++	connection = gb_connection_create(gbphy_dev->bundle,
++					  le16_to_cpu(gbphy_dev->cport_desc->id),
++					  gb_uart_request_handler);
++	if (IS_ERR(connection)) {
++		retval = PTR_ERR(connection);
++		goto exit_tty_free;
++	}
++
++	max_payload = gb_operation_get_payload_size_max(connection);
++	if (max_payload < sizeof(struct gb_uart_send_data_request)) {
++		retval = -EINVAL;
++		goto exit_connection_destroy;
++	}
++
++	gb_tty->buffer_payload_max = max_payload -
++			sizeof(struct gb_uart_send_data_request);
++
++	gb_tty->buffer = kzalloc(gb_tty->buffer_payload_max, GFP_KERNEL);
++	if (!gb_tty->buffer) {
++		retval = -ENOMEM;
++		goto exit_connection_destroy;
++	}
++
++	INIT_WORK(&gb_tty->tx_work, gb_uart_tx_write_work);
++
++	retval = kfifo_alloc(&gb_tty->write_fifo, GB_UART_WRITE_FIFO_SIZE,
++				GFP_KERNEL);
++	if (retval)
++		goto exit_buf_free;
++
++	gb_tty->credits = GB_UART_FIRMWARE_CREDITS;
++	init_completion(&gb_tty->credits_complete);
++
++	minor = alloc_minor(gb_tty);
++	if (minor < 0) {
++		if (minor == -ENOSPC) {
++			dev_err(&connection->bundle->dev,
++				"no more free minor numbers\n");
++			retval = -ENODEV;
++		} else {
++			retval = minor;
++		}
++		goto exit_kfifo_free;
++	}
++
++	gb_tty->minor = minor;
++	spin_lock_init(&gb_tty->write_lock);
++	spin_lock_init(&gb_tty->read_lock);
++	init_waitqueue_head(&gb_tty->wioctl);
++	mutex_init(&gb_tty->mutex);
++
++	tty_port_init(&gb_tty->port);
++	gb_tty->port.ops = &gb_port_ops;
++
++	gb_tty->connection = connection;
++	gb_tty->gbphy_dev = gbphy_dev;
++	gb_connection_set_data(connection, gb_tty);
++	gb_gbphy_set_data(gbphy_dev, gb_tty);
++
++	retval = gb_connection_enable_tx(connection);
++	if (retval)
++		goto exit_release_minor;
++
++	send_control(gb_tty, gb_tty->ctrlout);
++
++	/* initialize the uart to be 9600n81 */
++	gb_tty->line_coding.rate = cpu_to_le32(9600);
++	gb_tty->line_coding.format = GB_SERIAL_1_STOP_BITS;
++	gb_tty->line_coding.parity = GB_SERIAL_NO_PARITY;
++	gb_tty->line_coding.data_bits = 8;
++	send_line_coding(gb_tty);
++
++	retval = gb_connection_enable(connection);
++	if (retval)
++		goto exit_connection_disable;
++
++	tty_dev = tty_port_register_device(&gb_tty->port, gb_tty_driver, minor,
++					   &gbphy_dev->dev);
++	if (IS_ERR(tty_dev)) {
++		retval = PTR_ERR(tty_dev);
++		goto exit_connection_disable;
++	}
++
++	gbphy_runtime_put_autosuspend(gbphy_dev);
++	return 0;
++
++exit_connection_disable:
++	gb_connection_disable(connection);
++exit_release_minor:
++	release_minor(gb_tty);
++exit_kfifo_free:
++	kfifo_free(&gb_tty->write_fifo);
++exit_buf_free:
++	kfree(gb_tty->buffer);
++exit_connection_destroy:
++	gb_connection_destroy(connection);
++exit_tty_free:
++	kfree(gb_tty);
++
++	return retval;
++}
++
++static void gb_uart_remove(struct gbphy_device *gbphy_dev)
++{
++	struct gb_tty *gb_tty = gb_gbphy_get_data(gbphy_dev);
++	struct gb_connection *connection = gb_tty->connection;
++	struct tty_struct *tty;
++	int ret;
++
++	ret = gbphy_runtime_get_sync(gbphy_dev);
++	if (ret)
++		gbphy_runtime_get_noresume(gbphy_dev);
++
++	mutex_lock(&gb_tty->mutex);
++	gb_tty->disconnected = true;
++
++	wake_up_all(&gb_tty->wioctl);
++	mutex_unlock(&gb_tty->mutex);
++
++	tty = tty_port_tty_get(&gb_tty->port);
++	if (tty) {
++		tty_vhangup(tty);
++		tty_kref_put(tty);
++	}
++
++	gb_connection_disable_rx(connection);
++	tty_unregister_device(gb_tty_driver, gb_tty->minor);
++
++	/* FIXME - free transmit / receive buffers */
++
++	gb_connection_disable(connection);
++	tty_port_destroy(&gb_tty->port);
++	gb_connection_destroy(connection);
++	release_minor(gb_tty);
++	kfifo_free(&gb_tty->write_fifo);
++	kfree(gb_tty->buffer);
++	kfree(gb_tty);
++}
++
++static int gb_tty_init(void)
++{
++	int retval = 0;
++
++	gb_tty_driver = tty_alloc_driver(GB_NUM_MINORS, 0);
++	if (IS_ERR(gb_tty_driver)) {
++		pr_err("Can not allocate tty driver\n");
++		retval = -ENOMEM;
++		goto fail_unregister_dev;
++	}
++
++	gb_tty_driver->driver_name = "gb";
++	gb_tty_driver->name = GB_NAME;
++	gb_tty_driver->major = 0;
++	gb_tty_driver->minor_start = 0;
++	gb_tty_driver->type = TTY_DRIVER_TYPE_SERIAL;
++	gb_tty_driver->subtype = SERIAL_TYPE_NORMAL;
++	gb_tty_driver->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
++	gb_tty_driver->init_termios = tty_std_termios;
++	gb_tty_driver->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
++	tty_set_operations(gb_tty_driver, &gb_ops);
++
++	retval = tty_register_driver(gb_tty_driver);
++	if (retval) {
++		pr_err("Can not register tty driver: %d\n", retval);
++		goto fail_put_gb_tty;
++	}
++
++	return 0;
++
++fail_put_gb_tty:
++	put_tty_driver(gb_tty_driver);
++fail_unregister_dev:
++	return retval;
++}
++
++static void gb_tty_exit(void)
++{
++	tty_unregister_driver(gb_tty_driver);
++	put_tty_driver(gb_tty_driver);
++	idr_destroy(&tty_minors);
++}
++
++static const struct gbphy_device_id gb_uart_id_table[] = {
++	{ GBPHY_PROTOCOL(GREYBUS_PROTOCOL_UART) },
++	{ },
++};
++MODULE_DEVICE_TABLE(gbphy, gb_uart_id_table);
++
++static struct gbphy_driver uart_driver = {
++	.name		= "uart",
++	.probe		= gb_uart_probe,
++	.remove		= gb_uart_remove,
++	.id_table	= gb_uart_id_table,
++};
++
++static int gb_uart_driver_init(void)
++{
++	int ret;
++
++	ret = gb_tty_init();
++	if (ret)
++		return ret;
++
++	ret = gb_gbphy_register(&uart_driver);
++	if (ret) {
++		gb_tty_exit();
++		return ret;
++	}
++
++	return 0;
++}
++module_init(gb_uart_driver_init);
++
++static void gb_uart_driver_exit(void)
++{
++	gb_gbphy_deregister(&uart_driver);
++	gb_tty_exit();
++}
++
++module_exit(gb_uart_driver_exit);
++MODULE_LICENSE("GPL v2");