mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
242 lines
6.6 KiB
242 lines
6.6 KiB
// 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) != B0) |
|
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);
|
|
|