On 22. 02. 22, 7:51, Jiri Slaby wrote:
On 22. 02. 22, 2:14, Lino Sanfilippo wrote:
Several drivers that support setting the RS485 configuration via
userspace
implement one or more of the following tasks:
- in case of an invalid RTS configuration (both RTS after send and RTS on
send set or both unset) fall back to enable RTS on send and disable
RTS
after send
- nullify the padding field of the returned serial_rs485 struct
- copy the configuration into the uart port struct
- limit RTS delays to 100 ms
Move these tasks into the serial core to make them generic and to provide
a consistent behaviour among all drivers.
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@xxxxxx>
---
drivers/tty/serial/serial_core.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/drivers/tty/serial/serial_core.c
b/drivers/tty/serial/serial_core.c
index 846192a7b4bf..2b3afe038c1c 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -42,6 +42,11 @@ static struct lock_class_key port_lock_key;
#define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
+/*
+ * Max time with active RTS before/after data is sent.
+ */
+#define RS485_MAX_RTS_DELAY 100 /* msecs */
+
static void uart_change_speed(struct tty_struct *tty, struct
uart_state *state,
struct ktermios *old_termios);
static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
@@ -1282,8 +1287,32 @@ static int uart_set_rs485_config(struct
uart_port *port,
if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
return -EFAULT;
+ /* pick sane settings if the user hasn't */
+ if (!(rs485.flags & SER_RS485_RTS_ON_SEND) ==
+ !(rs485.flags & SER_RS485_RTS_AFTER_SEND)) {
+ pr_warn("invalid RTS setting, using RTS_ON_SEND instead\n");
Can't we have a device prefix here, so that everyone knows what device
is affected? Without that, it's not that useful. At least port->name &
port->line could be printed. The uart core uses dev_* prints, but prints
also line as uport->dev can be NULL sometimes.
And this comes from userspace, so should be ratelimited.
--
js
suse labs
