[PATCH u-boot-marvell v3 29/39] tools: kwboot: Allow any baudrate on Linux

[Stefan Roese]

On 24.09.21 23:07, Marek Behún wrote:
> From: Pali Rohár <pali at 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> (included by <sys/ioctl.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 at kernel.org>
> [ termios macros rewritten to static inline functions (for type control)
>    and moved to tools/termios_linux.h ]
> Signed-off-by: Marek Behún <marek.behun at nic.cz>

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan

> ---
>   tools/kwboot.c        |  16 +++-
>   tools/termios_linux.h | 189 ++++++++++++++++++++++++++++++++++++++++++
>   2 files changed, 204 insertions(+), 1 deletion(-)
>   create mode 100644 tools/termios_linux.h
> 
> diff --git a/tools/kwboot.c b/tools/kwboot.c
> index ba2fd10ff6..7ccab2993f 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
>    */
> @@ -554,7 +559,11 @@ kwboot_tty_baudrate_to_speed(int baudrate)
>   		return B50;
>   #endif
>   	default:
> +#ifdef BOTHER
> +		return BOTHER;
> +#else
>   		return B0;
> +#endif
>   	}
>   }
>   
> @@ -575,6 +584,11 @@ 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..d73989b625
> --- /dev/null
> +++ b/tools/termios_linux.h
> @@ -0,0 +1,189 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * termios fuctions to support arbitrary baudrates (on Linux)
> + *
> + * Copyright (c) 2021 Pali Rohár <pali at kernel.org>
> + * Copyright (c) 2021 Marek Behún <marek.behun at 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>
> + * (included by <sys/ioctl.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/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)
> +{
> +	if (s & ~CBAUD) {
> +		errno = EINVAL;
> +		return -1;
> +	}
> +
> +	t->c_cflag &= ~CBAUD;
> +	t->c_cflag |= s;
> +
> +	return 0;
> +}
> +
> +#ifdef IBSHIFT
> +static inline speed_t cfgetispeed(const struct termios *t)
> +{
> +	speed_t s = (t->c_cflag >> IBSHIFT) & CBAUD;
> +
> +	if (s == B0)
> +		return cfgetospeed(t);
> +	else
> +		return s;
> +}
> +
> +static inline int cfsetispeed(struct termios *t, speed_t s)
> +{
> +	if (s == 0)
> +		s = B0;
> +
> +	if (s & ~CBAUD) {
> +		errno = EINVAL;
> +		return -1;
> +	}
> +
> +	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)
> +{
> +	if (cfsetospeed(t, s))
> +		return -1;
> +#ifdef IBSHIFT
> +	if (cfsetispeed(t, s))
> +		return -1;
> +#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_ */
> 


Viele Grüße,
Stefan

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