From: Pali Rohár pali@kernel.org
The A38x platform supports more baudrates than just those defined by the Bn constants, and some of them are higher than the highest Bn baudrate (the highest is 4 MBd while A38x support 5.15 MBd).
On Linux, add support for arbitrary baudrates. (Since there is no standard POSIX API to specify arbitrary baudrate for a tty device, this change is Linux-specific.)
We need to use raw TCGETS2/TCSETS2 or TCGETS/TCSETS ioctls with the BOTHER flag in struct termios2/termios, defined in Linux headers <asm/ioctls.h> and <asm/termbits.h>. Since these headers conflict with glibc's header file <termios.h>, it is not possible to use libc's termios functions and we need to reimplement them via ioctl() calls.
Note that the Bnnn constants from <termios.h> need not be compatible with Bnnn constants from <asm/termbits.h>.
Signed-off-by: Pali Rohár pali@kernel.org [ termios macros rewritten to static inline functions (for type control) and moved to tools/termios.h ] Signed-off-by: Marek Behún marek.behun@nic.cz --- tools/kwboot.c | 16 +++- tools/termios_linux.h | 170 ++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 185 insertions(+), 1 deletion(-) create mode 100644 tools/termios_linux.h
diff --git a/tools/kwboot.c b/tools/kwboot.c index dbe59833eb..f60cfd130e 100644 --- a/tools/kwboot.c +++ b/tools/kwboot.c @@ -23,10 +23,15 @@ #include <errno.h> #include <unistd.h> #include <stdint.h> -#include <termios.h> #include <time.h> #include <sys/stat.h>
+#ifdef __linux__ +#include "termios_linux.h" +#else +#include <termios.h> +#endif + /* * Marvell BootROM UART Sensing */ @@ -553,7 +558,11 @@ kwboot_tty_baudrate_to_speed(int baudrate) return B50; #endif default: +#ifdef BOTHER + return BOTHER; +#else return B0; +#endif } }
@@ -574,6 +583,11 @@ kwboot_tty_change_baudrate(int fd, int baudrate) return -1; }
+#ifdef BOTHER + if (speed == BOTHER) + tio.c_ospeed = tio.c_ispeed = baudrate; +#endif + rc = cfsetospeed(&tio, speed); if (rc) return rc; diff --git a/tools/termios_linux.h b/tools/termios_linux.h new file mode 100644 index 0000000000..1c4223afa7 --- /dev/null +++ b/tools/termios_linux.h @@ -0,0 +1,170 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * termios fuctions to support arbitrary baudrates (on Linux) + * + * Copyright (c) 2021 Pali Rohár pali@kernel.org + * Copyright (c) 2021 Marek Behún marek.behun@nic.cz + */ + +#ifndef _TERMIOS_LINUX_H_ +#define _TERMIOS_LINUX_H_ + +/* + * We need to use raw TCGETS2/TCSETS2 or TCGETS/TCSETS ioctls with the BOTHER + * flag in struct termios2/termios, defined in Linux headers <asm/ioctls.h> and + * <asm/termbits.h>. Since these headers conflict with glibc's header file + * <termios.h>, it is not possible to use libc's termios functions and we need + * to reimplement them via ioctl() calls. + * + * An arbitrary baudrate is supported when the macro BOTHER is defined. The + * baudrate value itself is then stored into the c_ospeed and c_ispeed members. + * If ioctls TCGETS2/TCSETS2 are defined and supported then these fields are + * present in struct termios2, otherwise these fields are present in struct + * termios. + * + * Note that the Bnnn constants from <termios.h> need not be compatible with Bnnn + * constants from <asm/termbits.h>. + */ + +#include <errno.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <asm/ioctls.h> +#include <asm/termbits.h> + +#if defined(BOTHER) && defined(TCGETS2) +#define termios termios2 +#endif + +static inline int tcgetattr(int fd, struct termios *t) +{ +#if defined(BOTHER) && defined(TCGETS2) + return ioctl(fd, TCGETS2, t); +#else + return ioctl(fd, TCGETS, t); +#endif +} + +static inline int tcsetattr(int fd, int a, const struct termios *t) +{ + int cmd; + + switch (a) { +#if defined(BOTHER) && defined(TCGETS2) + case TCSANOW: + cmd = TCSETS2; + break; + case TCSADRAIN: + cmd = TCSETSW2; + break; + case TCSAFLUSH: + cmd = TCSETSF2; + break; +#else + case TCSANOW: + cmd = TCSETS; + break; + case TCSADRAIN: + cmd = TCSETSW; + break; + case TCSAFLUSH: + cmd = TCSETSF; + break; +#endif + default: + errno = EINVAL; + return -1; + } + + return ioctl(fd, cmd, t); +} + +static inline int tcdrain(int fd) +{ + return ioctl(fd, TCSBRK, 1); +} + +static inline int tcflush(int fd, int q) +{ + return ioctl(fd, TCFLSH, q); +} + +static inline int tcsendbreak(int fd, int d) +{ + return ioctl(fd, TCSBRK, d); +} + +static inline int tcflow(int fd, int a) +{ + return ioctl(fd, TCXONC, a); +} + +static inline pid_t tcgetsid(int fd) +{ + pid_t sid; + + if (ioctl(fd, TIOCGSID, &sid) < 0) + return (pid_t)-1; + + return sid; +} + +static inline speed_t cfgetospeed(const struct termios *t) +{ + return t->c_cflag & CBAUD; +} + +static inline int cfsetospeed(struct termios *t, speed_t s) +{ + t->c_cflag &= ~CBAUD; + t->c_cflag |= s; + + return 0; +} + +#ifdef IBSHIFT +static inline speed_t cfgetispeed(const struct termios *t) +{ + return (t->c_cflag >> IBSHIFT) & CBAUD; +} + +static inline int cfsetispeed(struct termios *t, speed_t s) +{ + t->c_cflag &= ~(CBAUD << IBSHIFT); + t->c_cflag |= s << IBSHIFT; + + return 0; +} +#else /* !IBSHIFT */ +static inline speed_t cfgetispeed(const struct termios *t) +{ + return cfgetospeed(t); +} + +static inline int cfsetispeed(struct termios *t, speed_t s) +{ + return cfsetospeed(t, s); +} +#endif /* !IBSHIFT */ + +static inline int cfsetspeed(struct termios *t, speed_t s) +{ + cfsetospeed(t, s); +#ifdef IBSHIFT + cfsetispeed(t, s); +#endif + + return 0; +} + +static void cfmakeraw(struct termios *t) +{ + t->c_iflag &= ~(IGNBRK | BRKINT | PARMRK | ISTRIP | INLCR | IGNCR | + ICRNL | IXON); + t->c_oflag &= ~OPOST; + t->c_lflag &= ~(ECHO | ECHONL | ICANON | ISIG | IEXTEN); + t->c_cflag &= ~(CSIZE | PARENB); + t->c_cflag |= CS8; +} + +#endif /* _TERMIOS_LINUX_H_ */