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Date: Fri, 16 Sep 2016 16:21:37 +0200
From: Greg KH <gregkh@...uxfoundation.org>
To: Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org
Cc: Johan Hovold <johan@...oldconsulting.com>,
Rui Miguel Silva <rmfrfs@...il.com>,
Laurent Pinchart <laurent.pinchart@...asonboard.com>,
Sandeep Patil <sspatil@...gle.com>,
Matt Porter <mporter@...nel.crashing.org>,
John Stultz <john.stultz@...aro.org>,
Rob Herring <robh@...nel.org>,
Viresh Kumar <viresh.kumar@...aro.org>,
Alex Elder <elder@...aro.org>, David Lin <dtwlin@...gle.com>,
Bryan O'Donoghue <pure.logic@...us-software.ie>,
Vaibhav Agarwal <vaibhav.agarwal@...aro.org>,
Mark Greer <mgreer@...malcreek.com>
Subject: [patch 28/32] greybus: bridged phy uart driver
This driver implements the Greybus bridged phy tty/uart class protocol.
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
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");
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