195 lines
3.7 KiB
C
195 lines
3.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* termios fuctions to support arbitrary baudrates (on Linux)
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*
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* Copyright (c) 2021 Pali Rohár <pali@kernel.org>
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* Copyright (c) 2021 Marek Behún <kabel@kernel.org>
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*/
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#ifndef _TERMIOS_LINUX_H_
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#define _TERMIOS_LINUX_H_
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/*
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* We need to use raw TCGETS2/TCSETS2 or TCGETS/TCSETS ioctls with the BOTHER
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* flag in struct termios2/termios, defined in Linux headers <asm/ioctls.h>
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* (included by <sys/ioctl.h>) and <asm/termbits.h>. Since these headers
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* conflict with glibc's header file <termios.h>, it is not possible to use
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* libc's termios functions and we need to reimplement them via ioctl() calls.
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*
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* An arbitrary baudrate is supported when the macro BOTHER is defined. The
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* baudrate value itself is then stored into the c_ospeed and c_ispeed members.
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* If ioctls TCGETS2/TCSETS2 are defined and supported then these fields are
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* present in struct termios2, otherwise these fields are present in struct
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* termios.
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*
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* Note that the Bnnn constants from <termios.h> need not be compatible with Bnnn
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* constants from <asm/termbits.h>.
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*/
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#include <errno.h>
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#include <sys/ioctl.h>
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#include <sys/types.h>
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#include <asm/ioctls.h>
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#include <asm/termbits.h>
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#if defined(BOTHER) && defined(TCGETS2)
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#define termios termios2
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#endif
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static inline int tcgetattr(int fd, struct termios *t)
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{
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#if defined(BOTHER) && defined(TCGETS2)
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return ioctl(fd, TCGETS2, t);
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#else
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return ioctl(fd, TCGETS, t);
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#endif
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}
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static inline int tcsetattr(int fd, int a, const struct termios *t)
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{
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int cmd;
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switch (a) {
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#if defined(BOTHER) && defined(TCGETS2)
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case TCSANOW:
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cmd = TCSETS2;
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break;
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case TCSADRAIN:
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cmd = TCSETSW2;
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break;
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case TCSAFLUSH:
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cmd = TCSETSF2;
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break;
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#else
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case TCSANOW:
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cmd = TCSETS;
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break;
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case TCSADRAIN:
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cmd = TCSETSW;
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break;
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case TCSAFLUSH:
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cmd = TCSETSF;
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break;
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#endif
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default:
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errno = EINVAL;
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return -1;
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}
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return ioctl(fd, cmd, t);
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}
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static inline int tcdrain(int fd)
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{
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return ioctl(fd, TCSBRK, 1);
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}
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static inline int tcflush(int fd, int q)
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{
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return ioctl(fd, TCFLSH, q);
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}
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static inline int tcsendbreak(int fd, int d)
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{
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#ifdef TCSBRKP
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return ioctl(fd, TCSBRKP, d);
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#else
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return ioctl(fd, TCSBRK, 0);
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#endif
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}
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static inline int tcflow(int fd, int a)
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{
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return ioctl(fd, TCXONC, a);
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}
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static inline pid_t tcgetsid(int fd)
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{
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pid_t sid;
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if (ioctl(fd, TIOCGSID, &sid) < 0)
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return (pid_t)-1;
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return sid;
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}
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static inline speed_t cfgetospeed(const struct termios *t)
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{
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return t->c_cflag & CBAUD;
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}
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static inline int cfsetospeed(struct termios *t, speed_t s)
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{
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if (s & ~CBAUD) {
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errno = EINVAL;
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return -1;
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}
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t->c_cflag &= ~CBAUD;
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t->c_cflag |= s;
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return 0;
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}
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#ifdef IBSHIFT
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static inline speed_t cfgetispeed(const struct termios *t)
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{
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speed_t s = (t->c_cflag >> IBSHIFT) & CBAUD;
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if (s == B0)
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return cfgetospeed(t);
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else
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return s;
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}
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static inline int cfsetispeed(struct termios *t, speed_t s)
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{
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if (s == 0)
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s = B0;
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if (s & ~CBAUD) {
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errno = EINVAL;
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return -1;
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}
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t->c_cflag &= ~(CBAUD << IBSHIFT);
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t->c_cflag |= s << IBSHIFT;
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return 0;
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}
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#else /* !IBSHIFT */
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static inline speed_t cfgetispeed(const struct termios *t)
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{
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return cfgetospeed(t);
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}
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static inline int cfsetispeed(struct termios *t, speed_t s)
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{
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return cfsetospeed(t, s);
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}
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#endif /* !IBSHIFT */
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static inline int cfsetspeed(struct termios *t, speed_t s)
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{
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if (cfsetospeed(t, s))
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return -1;
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#ifdef IBSHIFT
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if (cfsetispeed(t, s))
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return -1;
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#endif
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return 0;
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}
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static void cfmakeraw(struct termios *t)
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{
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t->c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR |
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ICRNL | IXON);
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t->c_oflag &= ~OPOST;
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t->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN);
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t->c_cflag &= ~(CSIZE | PARENB);
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t->c_cflag |= CS8;
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}
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#endif /* _TERMIOS_LINUX_H_ */
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