243 lines
6.6 KiB
C
243 lines
6.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/termios.h>
|
|
#include <linux/tty.h>
|
|
#include <linux/export.h>
|
|
#include "tty.h"
|
|
|
|
|
|
/*
|
|
* Routine which returns the baud rate of the tty
|
|
*
|
|
* Note that the baud_table needs to be kept in sync with the
|
|
* include/asm/termbits.h file.
|
|
*/
|
|
static const speed_t baud_table[] = {
|
|
0, 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400,
|
|
4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800,
|
|
#ifdef __sparc__
|
|
76800, 153600, 307200, 614400, 921600, 500000, 576000,
|
|
1000000, 1152000, 1500000, 2000000
|
|
#else
|
|
500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000,
|
|
2500000, 3000000, 3500000, 4000000
|
|
#endif
|
|
};
|
|
|
|
static const tcflag_t baud_bits[] = {
|
|
B0, B50, B75, B110, B134, B150, B200, B300, B600, B1200, B1800, B2400,
|
|
B4800, B9600, B19200, B38400, B57600, B115200, B230400, B460800,
|
|
#ifdef __sparc__
|
|
B76800, B153600, B307200, B614400, B921600, B500000, B576000,
|
|
B1000000, B1152000, B1500000, B2000000
|
|
#else
|
|
B500000, B576000, B921600, B1000000, B1152000, B1500000, B2000000,
|
|
B2500000, B3000000, B3500000, B4000000
|
|
#endif
|
|
};
|
|
|
|
static int n_baud_table = ARRAY_SIZE(baud_table);
|
|
|
|
/**
|
|
* tty_termios_baud_rate
|
|
* @termios: termios structure
|
|
*
|
|
* Convert termios baud rate data into a speed. This should be called
|
|
* with the termios lock held if this termios is a terminal termios
|
|
* structure. May change the termios data. Device drivers can call this
|
|
* function but should use ->c_[io]speed directly as they are updated.
|
|
*
|
|
* Locking: none
|
|
*/
|
|
|
|
speed_t tty_termios_baud_rate(struct ktermios *termios)
|
|
{
|
|
unsigned int cbaud;
|
|
|
|
cbaud = termios->c_cflag & CBAUD;
|
|
|
|
#ifdef BOTHER
|
|
/* Magic token for arbitrary speed via c_ispeed/c_ospeed */
|
|
if (cbaud == BOTHER)
|
|
return termios->c_ospeed;
|
|
#endif
|
|
if (cbaud & CBAUDEX) {
|
|
cbaud &= ~CBAUDEX;
|
|
|
|
if (cbaud < 1 || cbaud + 15 > n_baud_table)
|
|
termios->c_cflag &= ~CBAUDEX;
|
|
else
|
|
cbaud += 15;
|
|
}
|
|
return cbaud >= n_baud_table ? 0 : baud_table[cbaud];
|
|
}
|
|
EXPORT_SYMBOL(tty_termios_baud_rate);
|
|
|
|
/**
|
|
* tty_termios_input_baud_rate
|
|
* @termios: termios structure
|
|
*
|
|
* Convert termios baud rate data into a speed. This should be called
|
|
* with the termios lock held if this termios is a terminal termios
|
|
* structure. May change the termios data. Device drivers can call this
|
|
* function but should use ->c_[io]speed directly as they are updated.
|
|
*
|
|
* Locking: none
|
|
*/
|
|
|
|
speed_t tty_termios_input_baud_rate(struct ktermios *termios)
|
|
{
|
|
#ifdef IBSHIFT
|
|
unsigned int cbaud = (termios->c_cflag >> IBSHIFT) & CBAUD;
|
|
|
|
if (cbaud == B0)
|
|
return tty_termios_baud_rate(termios);
|
|
#ifdef BOTHER
|
|
/* Magic token for arbitrary speed via c_ispeed*/
|
|
if (cbaud == BOTHER)
|
|
return termios->c_ispeed;
|
|
#endif
|
|
if (cbaud & CBAUDEX) {
|
|
cbaud &= ~CBAUDEX;
|
|
|
|
if (cbaud < 1 || cbaud + 15 > n_baud_table)
|
|
termios->c_cflag &= ~(CBAUDEX << IBSHIFT);
|
|
else
|
|
cbaud += 15;
|
|
}
|
|
return cbaud >= n_baud_table ? 0 : baud_table[cbaud];
|
|
#else /* IBSHIFT */
|
|
return tty_termios_baud_rate(termios);
|
|
#endif /* IBSHIFT */
|
|
}
|
|
EXPORT_SYMBOL(tty_termios_input_baud_rate);
|
|
|
|
/**
|
|
* tty_termios_encode_baud_rate
|
|
* @termios: ktermios structure holding user requested state
|
|
* @ibaud: input speed
|
|
* @obaud: output speed
|
|
*
|
|
* Encode the speeds set into the passed termios structure. This is
|
|
* used as a library helper for drivers so that they can report back
|
|
* the actual speed selected when it differs from the speed requested
|
|
*
|
|
* For maximal back compatibility with legacy SYS5/POSIX *nix behaviour
|
|
* we need to carefully set the bits when the user does not get the
|
|
* desired speed. We allow small margins and preserve as much of possible
|
|
* of the input intent to keep compatibility.
|
|
*
|
|
* Locking: Caller should hold termios lock. This is already held
|
|
* when calling this function from the driver termios handler.
|
|
*
|
|
* The ifdefs deal with platforms whose owners have yet to update them
|
|
* and will all go away once this is done.
|
|
*/
|
|
|
|
void tty_termios_encode_baud_rate(struct ktermios *termios,
|
|
speed_t ibaud, speed_t obaud)
|
|
{
|
|
int i = 0;
|
|
int ifound = -1, ofound = -1;
|
|
int iclose = ibaud/50, oclose = obaud/50;
|
|
int ibinput = 0;
|
|
|
|
if (obaud == 0) /* CD dropped */
|
|
ibaud = 0; /* Clear ibaud to be sure */
|
|
|
|
termios->c_ispeed = ibaud;
|
|
termios->c_ospeed = obaud;
|
|
|
|
#ifdef IBSHIFT
|
|
if ((termios->c_cflag >> IBSHIFT) & CBAUD)
|
|
ibinput = 1; /* An input speed was specified */
|
|
#endif
|
|
#ifdef BOTHER
|
|
/* If the user asked for a precise weird speed give a precise weird
|
|
* answer. If they asked for a Bfoo speed they may have problems
|
|
* digesting non-exact replies so fuzz a bit.
|
|
*/
|
|
|
|
if ((termios->c_cflag & CBAUD) == BOTHER) {
|
|
oclose = 0;
|
|
if (!ibinput)
|
|
iclose = 0;
|
|
}
|
|
if (((termios->c_cflag >> IBSHIFT) & CBAUD) == BOTHER)
|
|
iclose = 0;
|
|
#endif
|
|
termios->c_cflag &= ~CBAUD;
|
|
#ifdef IBSHIFT
|
|
termios->c_cflag &= ~(CBAUD << IBSHIFT);
|
|
#endif
|
|
|
|
/*
|
|
* Our goal is to find a close match to the standard baud rate
|
|
* returned. Walk the baud rate table and if we get a very close
|
|
* match then report back the speed as a POSIX Bxxxx value by
|
|
* preference
|
|
*/
|
|
|
|
do {
|
|
if (obaud - oclose <= baud_table[i] &&
|
|
obaud + oclose >= baud_table[i]) {
|
|
termios->c_cflag |= baud_bits[i];
|
|
ofound = i;
|
|
}
|
|
if (ibaud - iclose <= baud_table[i] &&
|
|
ibaud + iclose >= baud_table[i]) {
|
|
/* For the case input == output don't set IBAUD bits
|
|
* if the user didn't do so.
|
|
*/
|
|
if (ofound == i && !ibinput)
|
|
ifound = i;
|
|
#ifdef IBSHIFT
|
|
else {
|
|
ifound = i;
|
|
termios->c_cflag |= (baud_bits[i] << IBSHIFT);
|
|
}
|
|
#endif
|
|
}
|
|
} while (++i < n_baud_table);
|
|
|
|
/*
|
|
* If we found no match then use BOTHER if provided or warn
|
|
* the user their platform maintainer needs to wake up if not.
|
|
*/
|
|
#ifdef BOTHER
|
|
if (ofound == -1)
|
|
termios->c_cflag |= BOTHER;
|
|
/* Set exact input bits only if the input and output differ or the
|
|
* user already did.
|
|
*/
|
|
if (ifound == -1 && (ibaud != obaud || ibinput))
|
|
termios->c_cflag |= (BOTHER << IBSHIFT);
|
|
#else
|
|
if (ifound == -1 || ofound == -1)
|
|
pr_warn_once("tty: Unable to return correct speed data as your architecture needs updating.\n");
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate);
|
|
|
|
/**
|
|
* tty_encode_baud_rate - set baud rate of the tty
|
|
* @tty: terminal device
|
|
* @ibaud: input baud rate
|
|
* @obaud: output baud rate
|
|
*
|
|
* Update the current termios data for the tty with the new speed
|
|
* settings. The caller must hold the termios_rwsem for the tty in
|
|
* question.
|
|
*/
|
|
|
|
void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud)
|
|
{
|
|
tty_termios_encode_baud_rate(&tty->termios, ibaud, obaud);
|
|
}
|
|
EXPORT_SYMBOL_GPL(tty_encode_baud_rate);
|