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 <[email protected]>
---
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");
+ rs485.flags |= SER_RS485_RTS_ON_SEND;
+ rs485.flags &= ~SER_RS485_RTS_AFTER_SEND;
+ }
+
+ if (rs485.delay_rts_before_send > RS485_MAX_RTS_DELAY) {
+ rs485.delay_rts_before_send = RS485_MAX_RTS_DELAY;
+ pr_warn("RTS delay before sending clamped to %u ms\n",
+ rs485.delay_rts_before_send);
+ }
+
+ if (rs485.delay_rts_after_send > RS485_MAX_RTS_DELAY) {
+ rs485.delay_rts_after_send = RS485_MAX_RTS_DELAY;
+ pr_warn("RTS delay after sending clamped to %u ms\n",
+ rs485.delay_rts_after_send);
+ }
+ /* Return clean padding area to userspace */
+ memset(rs485.padding, 0, sizeof(rs485.padding));
+
spin_lock_irqsave(&port->lock, flags);
ret = port->rs485_config(port, &rs485);
+ if (!ret)
+ port->rs485 = rs485;
spin_unlock_irqrestore(&port->lock, flags);
if (ret)
return ret;
base-commit: a603ca60cebff8589882427a67f870ed946b3fc8
--
2.35.1
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 <[email protected]>
> ---
> 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.
Hm, we could introduce uart_print family (to print something like what
is in uart_report_port).
thanks,
--
js
suse labs
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 <[email protected]>
>> ---
>> 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
Hi,
> 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 <[email protected]>
> >> ---
> >> 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.
>
Right, ratelimiting makes sense here. I will change it as suggested in the next patch version.
Thanks a lot for the review.
Regards,
Lino