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linux/drivers/usb/serial/ssu100.c
Johan Hovold 01fd45f676 USB: serial: add generic support for TIOCSSERIAL 
TIOCSSERIAL is a horrid, underspecified, legacy interface which for most
serial devices is only useful for setting the close_delay and
closing_wait parameters.

The closing_wait parameter determines how long to wait for the transfer
buffers to drain during close and the default timeout of 30 seconds may
not be sufficient at low line speeds. In other cases, when for example
flow is stopped, the default timeout may instead be too long.

Add generic support for TIOCSSERIAL and TIOCGSERIAL with handling of the
three common parameters close_delay, closing_wait and line for the
benefit of all USB serial drivers while still allowing drivers to
implement further functionality through the existing callbacks.

This currently includes a few drivers that report their base baud clock
rate even if that is really only of interest when setting custom
divisors through the deprecated ASYNC_SPD_CUST interface; an interface
which only the FTDI driver actually implements.

Some drivers have also been reporting back a fake UART type, something
which should no longer be needed and will be dropped by a follow-on
patch.

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Johan Hovold <johan@kernel.org>
2021-04-08 09:46:02 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* usb-serial driver for Quatech SSU-100
*
* based on ftdi_sio.c and the original serqt_usb.c from Quatech
*
*/
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_driver.h>
#include <linux/tty_flip.h>
#include <linux/module.h>
#include <linux/serial.h>
#include <linux/usb.h>
#include <linux/usb/serial.h>
#include <linux/serial_reg.h>
#include <linux/uaccess.h>
#define QT_OPEN_CLOSE_CHANNEL 0xca
#define QT_SET_GET_DEVICE 0xc2
#define QT_SET_GET_REGISTER 0xc0
#define QT_GET_SET_PREBUF_TRIG_LVL 0xcc
#define QT_SET_ATF 0xcd
#define QT_GET_SET_UART 0xc1
#define QT_TRANSFER_IN 0xc0
#define QT_HW_FLOW_CONTROL_MASK 0xc5
#define QT_SW_FLOW_CONTROL_MASK 0xc6
#define SERIAL_MSR_MASK 0xf0
#define SERIAL_CRTSCTS ((UART_MCR_RTS << 8) | UART_MSR_CTS)
#define SERIAL_EVEN_PARITY (UART_LCR_PARITY | UART_LCR_EPAR)
#define MAX_BAUD_RATE 460800
#define ATC_DISABLED 0x00
#define DUPMODE_BITS 0xc0
#define RR_BITS 0x03
#define LOOPMODE_BITS 0x41
#define RS232_MODE 0x00
#define RTSCTS_TO_CONNECTOR 0x40
#define CLKS_X4 0x02
#define FULLPWRBIT 0x00000080
#define NEXT_BOARD_POWER_BIT 0x00000004
#define DRIVER_DESC "Quatech SSU-100 USB to Serial Driver"
#define USB_VENDOR_ID_QUATECH 0x061d /* Quatech VID */
#define QUATECH_SSU100 0xC020 /* SSU100 */
static const struct usb_device_id id_table[] = {
{USB_DEVICE(USB_VENDOR_ID_QUATECH, QUATECH_SSU100)},
{} /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, id_table);
struct ssu100_port_private {
spinlock_t status_lock;
u8 shadowLSR;
u8 shadowMSR;
};
static inline int ssu100_control_msg(struct usb_device *dev,
u8 request, u16 data, u16 index)
{
return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
request, 0x40, data, index,
NULL, 0, 300);
}
static inline int ssu100_setdevice(struct usb_device *dev, u8 *data)
{
u16 x = ((u16)(data[1] << 8) | (u16)(data[0]));
return ssu100_control_msg(dev, QT_SET_GET_DEVICE, x, 0);
}
static inline int ssu100_getdevice(struct usb_device *dev, u8 *data)
{
int ret;
ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
QT_SET_GET_DEVICE, 0xc0, 0, 0,
data, 3, 300);
if (ret < 3) {
if (ret >= 0)
ret = -EIO;
}
return ret;
}
static inline int ssu100_getregister(struct usb_device *dev,
unsigned short uart,
unsigned short reg,
u8 *data)
{
int ret;
ret = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
QT_SET_GET_REGISTER, 0xc0, reg,
uart, data, sizeof(*data), 300);
if (ret < (int)sizeof(*data)) {
if (ret >= 0)
ret = -EIO;
}
return ret;
}
static inline int ssu100_setregister(struct usb_device *dev,
unsigned short uart,
unsigned short reg,
u16 data)
{
u16 value = (data << 8) | reg;
return usb_control_msg(dev, usb_sndctrlpipe(dev, 0),
QT_SET_GET_REGISTER, 0x40, value, uart,
NULL, 0, 300);
}
#define set_mctrl(dev, set) update_mctrl((dev), (set), 0)
#define clear_mctrl(dev, clear) update_mctrl((dev), 0, (clear))
/* these do not deal with device that have more than 1 port */
static inline int update_mctrl(struct usb_device *dev, unsigned int set,
unsigned int clear)
{
unsigned urb_value;
int result;
if (((set | clear) & (TIOCM_DTR | TIOCM_RTS)) == 0) {
dev_dbg(&dev->dev, "%s - DTR|RTS not being set|cleared\n", __func__);
return 0; /* no change */
}
clear &= ~set; /* 'set' takes precedence over 'clear' */
urb_value = 0;
if (set & TIOCM_DTR)
urb_value |= UART_MCR_DTR;
if (set & TIOCM_RTS)
urb_value |= UART_MCR_RTS;
result = ssu100_setregister(dev, 0, UART_MCR, urb_value);
if (result < 0)
dev_dbg(&dev->dev, "%s Error from MODEM_CTRL urb\n", __func__);
return result;
}
static int ssu100_initdevice(struct usb_device *dev)
{
u8 *data;
int result = 0;
data = kzalloc(3, GFP_KERNEL);
if (!data)
return -ENOMEM;
result = ssu100_getdevice(dev, data);
if (result < 0) {
dev_dbg(&dev->dev, "%s - get_device failed %i\n", __func__, result);
goto out;
}
data[1] &= ~FULLPWRBIT;
result = ssu100_setdevice(dev, data);
if (result < 0) {
dev_dbg(&dev->dev, "%s - setdevice failed %i\n", __func__, result);
goto out;
}
result = ssu100_control_msg(dev, QT_GET_SET_PREBUF_TRIG_LVL, 128, 0);
if (result < 0) {
dev_dbg(&dev->dev, "%s - set prebuffer level failed %i\n", __func__, result);
goto out;
}
result = ssu100_control_msg(dev, QT_SET_ATF, ATC_DISABLED, 0);
if (result < 0) {
dev_dbg(&dev->dev, "%s - set ATFprebuffer level failed %i\n", __func__, result);
goto out;
}
result = ssu100_getdevice(dev, data);
if (result < 0) {
dev_dbg(&dev->dev, "%s - get_device failed %i\n", __func__, result);
goto out;
}
data[0] &= ~(RR_BITS | DUPMODE_BITS);
data[0] |= CLKS_X4;
data[1] &= ~(LOOPMODE_BITS);
data[1] |= RS232_MODE;
result = ssu100_setdevice(dev, data);
if (result < 0) {
dev_dbg(&dev->dev, "%s - setdevice failed %i\n", __func__, result);
goto out;
}
out: kfree(data);
return result;
}
static void ssu100_set_termios(struct tty_struct *tty,
struct usb_serial_port *port,
struct ktermios *old_termios)
{
struct usb_device *dev = port->serial->dev;
struct ktermios *termios = &tty->termios;
u16 baud, divisor, remainder;
unsigned int cflag = termios->c_cflag;
u16 urb_value = 0; /* will hold the new flags */
int result;
if (cflag & PARENB) {
if (cflag & PARODD)
urb_value |= UART_LCR_PARITY;
else
urb_value |= SERIAL_EVEN_PARITY;
}
switch (cflag & CSIZE) {
case CS5:
urb_value |= UART_LCR_WLEN5;
break;
case CS6:
urb_value |= UART_LCR_WLEN6;
break;
case CS7:
urb_value |= UART_LCR_WLEN7;
break;
default:
case CS8:
urb_value |= UART_LCR_WLEN8;
break;
}
baud = tty_get_baud_rate(tty);
if (!baud)
baud = 9600;
dev_dbg(&port->dev, "%s - got baud = %d\n", __func__, baud);
divisor = MAX_BAUD_RATE / baud;
remainder = MAX_BAUD_RATE % baud;
if (((remainder * 2) >= baud) && (baud != 110))
divisor++;
urb_value = urb_value << 8;
result = ssu100_control_msg(dev, QT_GET_SET_UART, divisor, urb_value);
if (result < 0)
dev_dbg(&port->dev, "%s - set uart failed\n", __func__);
if (cflag & CRTSCTS)
result = ssu100_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
SERIAL_CRTSCTS, 0);
else
result = ssu100_control_msg(dev, QT_HW_FLOW_CONTROL_MASK,
0, 0);
if (result < 0)
dev_dbg(&port->dev, "%s - set HW flow control failed\n", __func__);
if (I_IXOFF(tty) || I_IXON(tty)) {
u16 x = ((u16)(START_CHAR(tty) << 8) | (u16)(STOP_CHAR(tty)));
result = ssu100_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
x, 0);
} else
result = ssu100_control_msg(dev, QT_SW_FLOW_CONTROL_MASK,
0, 0);
if (result < 0)
dev_dbg(&port->dev, "%s - set SW flow control failed\n", __func__);
}
static int ssu100_open(struct tty_struct *tty, struct usb_serial_port *port)
{
struct usb_device *dev = port->serial->dev;
struct ssu100_port_private *priv = usb_get_serial_port_data(port);
u8 *data;
int result;
unsigned long flags;
data = kzalloc(2, GFP_KERNEL);
if (!data)
return -ENOMEM;
result = usb_control_msg(dev, usb_rcvctrlpipe(dev, 0),
QT_OPEN_CLOSE_CHANNEL,
QT_TRANSFER_IN, 0x01,
0, data, 2, 300);
if (result < 2) {
dev_dbg(&port->dev, "%s - open failed %i\n", __func__, result);
if (result >= 0)
result = -EIO;
kfree(data);
return result;
}
spin_lock_irqsave(&priv->status_lock, flags);
priv->shadowLSR = data[0];
priv->shadowMSR = data[1];
spin_unlock_irqrestore(&priv->status_lock, flags);
kfree(data);
/* set to 9600 */
result = ssu100_control_msg(dev, QT_GET_SET_UART, 0x30, 0x0300);
if (result < 0)
dev_dbg(&port->dev, "%s - set uart failed\n", __func__);
if (tty)
ssu100_set_termios(tty, port, &tty->termios);
return usb_serial_generic_open(tty, port);
}
static int ssu100_attach(struct usb_serial *serial)
{
return ssu100_initdevice(serial->dev);
}
static int ssu100_port_probe(struct usb_serial_port *port)
{
struct ssu100_port_private *priv;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
spin_lock_init(&priv->status_lock);
usb_set_serial_port_data(port, priv);
return 0;
}
static void ssu100_port_remove(struct usb_serial_port *port)
{
struct ssu100_port_private *priv;
priv = usb_get_serial_port_data(port);
kfree(priv);
}
static int ssu100_tiocmget(struct tty_struct *tty)
{
struct usb_serial_port *port = tty->driver_data;
struct usb_device *dev = port->serial->dev;
u8 *d;
int r;
d = kzalloc(2, GFP_KERNEL);
if (!d)
return -ENOMEM;
r = ssu100_getregister(dev, 0, UART_MCR, d);
if (r < 0)
goto mget_out;
r = ssu100_getregister(dev, 0, UART_MSR, d+1);
if (r < 0)
goto mget_out;
r = (d[0] & UART_MCR_DTR ? TIOCM_DTR : 0) |
(d[0] & UART_MCR_RTS ? TIOCM_RTS : 0) |
(d[1] & UART_MSR_CTS ? TIOCM_CTS : 0) |
(d[1] & UART_MSR_DCD ? TIOCM_CAR : 0) |
(d[1] & UART_MSR_RI ? TIOCM_RI : 0) |
(d[1] & UART_MSR_DSR ? TIOCM_DSR : 0);
mget_out:
kfree(d);
return r;
}
static int ssu100_tiocmset(struct tty_struct *tty,
unsigned int set, unsigned int clear)
{
struct usb_serial_port *port = tty->driver_data;
struct usb_device *dev = port->serial->dev;
return update_mctrl(dev, set, clear);
}
static void ssu100_dtr_rts(struct usb_serial_port *port, int on)
{
struct usb_device *dev = port->serial->dev;
/* Disable flow control */
if (!on) {
if (ssu100_setregister(dev, 0, UART_MCR, 0) < 0)
dev_err(&port->dev, "error from flowcontrol urb\n");
}
/* drop RTS and DTR */
if (on)
set_mctrl(dev, TIOCM_DTR | TIOCM_RTS);
else
clear_mctrl(dev, TIOCM_DTR | TIOCM_RTS);
}
static void ssu100_update_msr(struct usb_serial_port *port, u8 msr)
{
struct ssu100_port_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
spin_lock_irqsave(&priv->status_lock, flags);
priv->shadowMSR = msr;
spin_unlock_irqrestore(&priv->status_lock, flags);
if (msr & UART_MSR_ANY_DELTA) {
/* update input line counters */
if (msr & UART_MSR_DCTS)
port->icount.cts++;
if (msr & UART_MSR_DDSR)
port->icount.dsr++;
if (msr & UART_MSR_DDCD)
port->icount.dcd++;
if (msr & UART_MSR_TERI)
port->icount.rng++;
wake_up_interruptible(&port->port.delta_msr_wait);
}
}
static void ssu100_update_lsr(struct usb_serial_port *port, u8 lsr,
char *tty_flag)
{
struct ssu100_port_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
spin_lock_irqsave(&priv->status_lock, flags);
priv->shadowLSR = lsr;
spin_unlock_irqrestore(&priv->status_lock, flags);
*tty_flag = TTY_NORMAL;
if (lsr & UART_LSR_BRK_ERROR_BITS) {
/* we always want to update icount, but we only want to
* update tty_flag for one case */
if (lsr & UART_LSR_BI) {
port->icount.brk++;
*tty_flag = TTY_BREAK;
usb_serial_handle_break(port);
}
if (lsr & UART_LSR_PE) {
port->icount.parity++;
if (*tty_flag == TTY_NORMAL)
*tty_flag = TTY_PARITY;
}
if (lsr & UART_LSR_FE) {
port->icount.frame++;
if (*tty_flag == TTY_NORMAL)
*tty_flag = TTY_FRAME;
}
if (lsr & UART_LSR_OE) {
port->icount.overrun++;
tty_insert_flip_char(&port->port, 0, TTY_OVERRUN);
}
}
}
static void ssu100_process_read_urb(struct urb *urb)
{
struct usb_serial_port *port = urb->context;
char *packet = urb->transfer_buffer;
char flag = TTY_NORMAL;
u32 len = urb->actual_length;
int i;
char *ch;
if ((len >= 4) &&
(packet[0] == 0x1b) && (packet[1] == 0x1b) &&
((packet[2] == 0x00) || (packet[2] == 0x01))) {
if (packet[2] == 0x00)
ssu100_update_lsr(port, packet[3], &flag);
if (packet[2] == 0x01)
ssu100_update_msr(port, packet[3]);
len -= 4;
ch = packet + 4;
} else
ch = packet;
if (!len)
return; /* status only */
if (port->sysrq) {
for (i = 0; i < len; i++, ch++) {
if (!usb_serial_handle_sysrq_char(port, *ch))
tty_insert_flip_char(&port->port, *ch, flag);
}
} else {
tty_insert_flip_string_fixed_flag(&port->port, ch, flag, len);
}
tty_flip_buffer_push(&port->port);
}
static struct usb_serial_driver ssu100_device = {
.driver = {
.owner = THIS_MODULE,
.name = "ssu100",
},
.description = DRIVER_DESC,
.id_table = id_table,
.num_ports = 1,
.open = ssu100_open,
.attach = ssu100_attach,
.port_probe = ssu100_port_probe,
.port_remove = ssu100_port_remove,
.dtr_rts = ssu100_dtr_rts,
.process_read_urb = ssu100_process_read_urb,
.tiocmget = ssu100_tiocmget,
.tiocmset = ssu100_tiocmset,
.tiocmiwait = usb_serial_generic_tiocmiwait,
.get_icount = usb_serial_generic_get_icount,
.set_termios = ssu100_set_termios,
};
static struct usb_serial_driver * const serial_drivers[] = {
&ssu100_device, NULL
};
module_usb_serial_driver(serial_drivers, id_table);
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL v2");
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