| /* |
| * 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> |
| |
| |
| /* |
| * 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 |
| #else |
| 500000, 576000, 921600, 1000000, 1152000, 1500000, 2000000, |
| 2500000, 3000000, 3500000, 4000000 |
| #endif |
| }; |
| |
| #ifndef __sparc__ |
| 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, B500000, B576000, |
| B921600, B1000000, B1152000, B1500000, B2000000, B2500000, |
| B3000000, B3500000, B4000000 |
| }; |
| #else |
| 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, B76800, B153600, |
| B307200, B614400, B921600 |
| }; |
| #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); |
| |
| /* Magic token for arbitrary speed via c_ispeed*/ |
| if (cbaud == BOTHER) |
| return termios->c_ispeed; |
| |
| 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 |
| return tty_termios_baud_rate(termios); |
| #endif |
| } |
| EXPORT_SYMBOL(tty_termios_input_baud_rate); |
| |
| /** |
| * tty_termios_encode_baud_rate |
| * @termios: ktermios structure holding user requested state |
| * @ispeed: input speed |
| * @ospeed: 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 BOTHER |
| if ((termios->c_cflag >> IBSHIFT) & CBAUD) |
| ibinput = 1; /* An input speed was specified */ |
| |
| /* 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 |
| * @ibaud: input baud rate |
| * @obad: 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); |