2015-03-27 12:32 GMT+01:00 Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>:
> On 03/26/2015 06:03 PM, Maxime Coquelin wrote:
>>>> +static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
>>>> + struct ktermios *old)
>>>> +{
>>>> + unsigned int baud;
>>>> + u32 usardiv, mantissa, fraction;
>>>> + tcflag_t cflag;
>>>> + u32 cr1, cr2, cr3;
>>>> + unsigned long flags;
>>>> +
>>>> + baud = uart_get_baud_rate(port, termios, old, 0, port->uartclk / 16);
>>>> + cflag = termios->c_cflag;
>>>> +
>>>> + spin_lock_irqsave(&port->lock, flags);
>>>> +
>>>> + /* Stop serial port and reset value */
>>>> + writel_relaxed(0, port->membase + USART_CR1);
>>>> +
>>>> + cr1 = USART_CR1_TE | USART_CR1_RE | USART_CR1_UE | USART_CR1_RXNEIE;
>>>> +
>>>> + if (cflag & CSTOPB)
>>>> + cr2 = USART_CR2_STOP_2B;
>>>> +
>>>> + if (cflag & PARENB) {
>>>> + cr1 |= USART_CR1_PCE;
>>>> + if ((cflag & CSIZE) == CS8)
>>>> + cr1 |= USART_CR1_M;
>>>> + }
>>>> +
>>>> + if (cflag & PARODD)
>>>> + cr1 |= USART_CR1_PS;
>>>> +
>>>> + if (cflag & CRTSCTS)
>>>> + cr3 = USART_CR3_RTSE | USART_CR3_CTSE;
>>>
>>> If this means autoflow control, then you need to define
>>> throttle()/unthrottle() methods, otherwise the serial core won't
>>> be able to throttle the remote when input buffers are about
>>> to overflow.
>>>
>>> And you should only enable the autoCTS and let the serial
>>> core enable autoRTS through set_mctrl(TIOCM_RTS).
>>>
>>> Just let me know if you need more info about how to do this.
>>
>> Ok, let's see if I have well understood.
>>
>> USART_CR3_RTSE should be set/cleared in set_mctrl(), depending on
>> TIOCM_RTS value.
>> The throttle callback should disable the rx interrupt, and the
>> unthrottle enable it.
>> For CTS, it should be enabled in set_termios() if CRTSCTS, as done here.
>>
>> Am I right?
>
> Yeah, basically. You also have to indicate to the serial core that you
> require throttle/unthrottle handling in this mode by setting port->status.
>
> Your set_termios() method would look like:
>
> port->status &= ~(UPSTAT_AUTOCTS | UPSTAT_AUTORTS);
> if (cflag & CRTSCTS) {
> port->status |= UPSTAT_AUTOCTS | UPSTAT_AUTORTS;
> cr3 = USART_CR3_CTSE;
> }
>
> and your set_mctrl() method would look like:
>
> if ((mctrl & TIOCM_RTS) && (port->status & UPSTAT_AUTORTS))
> stm32_set_bits(port, USART_CR3, USART_CR3_RTSE);
> else
> stm32_clear_bits(port, USART_CR3, USART_CR3_RTSE);
>
> The UPSTAT_AUTOCTS doesn't really do anything right now but please
> use it anyway to indicate this driver has that functionality.
Ok, thanks for your support.
I will implement this in the v4.
Regards,
Maxime
>
> Regards,
> Peter Hurley
>
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