diff options
| author | Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> | 2022-06-24 23:42:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-27 15:44:20 +0300 |
| commit | 4f768e94774c58c9f7f54ebd38dadf172970046a (patch) | |
| tree | f237520975e9f0839fd2dbbd911d2681288f949e /drivers/tty | |
| parent | ae50bb2752836277ae15aa4e9d99074d6d947946 (diff) | |
serial: Support for RS-485 multipoint addresses
Add support for RS-485 multipoint addressing using 9th bit [*]. The
addressing mode is configured through ->rs485_config().
ADDRB in termios indicates 9th bit addressing mode is enabled. In this
mode, 9th bit is used to indicate an address (byte) within the
communication line. ADDRB can only be enabled/disabled through
->rs485_config() that is also responsible for setting the destination and
receiver (filter) addresses.
Add traps to detect unwanted changes to struct serial_rs485 layout using
static_assert().
[*] Technically, RS485 is just an electronic spec and does not itself
specify the 9th bit addressing mode but 9th bit seems at least
"semi-standard" way to do addressing with RS485.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220624204210.11112-6-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/serial_core.c | 22 | ||||
| -rw-r--r-- | drivers/tty/tty_ioctl.c | 4 |
2 files changed, 25 insertions, 1 deletions
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index 2529153c8979..85ef7ef00b82 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1288,6 +1288,17 @@ static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *r if (flags & ~port->rs485_supported->flags) return -EINVAL; + /* Asking for address w/o addressing mode? */ + if (!(rs485->flags & SER_RS485_ADDRB) && + (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST))) + return -EINVAL; + + /* Address given but not enabled? */ + if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv) + return -EINVAL; + if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest) + return -EINVAL; + return 0; } @@ -1343,7 +1354,8 @@ static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs4 rs485->flags &= supported_flags; /* Return clean padding area to userspace */ - memset(rs485->padding, 0, sizeof(rs485->padding)); + memset(rs485->padding0, 0, sizeof(rs485->padding0)); + memset(rs485->padding1, 0, sizeof(rs485->padding1)); } int uart_rs485_config(struct uart_port *port) @@ -3402,5 +3414,13 @@ int uart_get_rs485_mode(struct uart_port *port) } EXPORT_SYMBOL_GPL(uart_get_rs485_mode); +/* Compile-time assertions for serial_rs485 layout */ +static_assert(offsetof(struct serial_rs485, padding) == + (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32))); +static_assert(offsetof(struct serial_rs485, padding1) == + offsetof(struct serial_rs485, padding[1])); +static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) == + sizeof(struct serial_rs485)); + MODULE_DESCRIPTION("Serial driver core"); MODULE_LICENSE("GPL"); diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c index adae687f654b..2a76b330e108 100644 --- a/drivers/tty/tty_ioctl.c +++ b/drivers/tty/tty_ioctl.c @@ -319,6 +319,8 @@ unsigned char tty_get_frame_size(unsigned int cflag) bits++; if (cflag & PARENB) bits++; + if (cflag & ADDRB) + bits++; return bits; } @@ -353,6 +355,8 @@ int tty_set_termios(struct tty_struct *tty, struct ktermios *new_termios) old_termios = tty->termios; tty->termios = *new_termios; unset_locked_termios(tty, &old_termios); + /* Reset any ADDRB changes, ADDRB is changed through ->rs485_config() */ + tty->termios.c_cflag ^= (tty->termios.c_cflag ^ old_termios.c_cflag) & ADDRB; if (tty->ops->set_termios) tty->ops->set_termios(tty, &old_termios); |