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Groups > linux.kernel > #1267984 > unrolled thread

[PATCH v3 0/5] tty: Introduce software RS485 direction control support

Started by"Matwey V. Kornilov" <matwey@sai.msu.ru>
First post2015-11-12 15:40 +0100
Last post2015-11-12 15:40 +0100
Articles 6 — 2 participants

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Contents

  [PATCH v3 0/5] tty: Introduce software RS485 direction control support "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-12 15:40 +0100
    [PATCH v3 4/5] tty: Move serial8250_stop_rx in front of serial8250_start_tx "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-12 15:40 +0100
    [PATCH v3 5/5] tty: Add software emulated RS485 support for 8250 "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-12 15:40 +0100
      Re: [PATCH v3 5/5] tty: Add software emulated RS485 support for 8250 Andy Shevchenko <andy.shevchenko@gmail.com> - 2015-11-12 15:50 +0100
    [PATCH v3 1/5] tty: Introduce UART_CAP_HW485 "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-12 15:40 +0100
    [PATCH v3 3/5] tty: Implement default fallback serial8250_rs485_config "Matwey V. Kornilov" <matwey@sai.msu.ru> - 2015-11-12 15:40 +0100

#1267984 — [PATCH v3 0/5] tty: Introduce software RS485 direction control support

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-12 15:40 +0100
Subject[PATCH v3 0/5] tty: Introduce software RS485 direction control support
Message-ID<qu1cC-1EX-7@gated-at.bofh.it>
Changes from v2:
 - Introduced SER_RS485_SOFTWARE to show that software implementation is being used
 - serial8250_rs485_config is located as required
 - Timers are used to implement delay_before and delay_after timeouts
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#1267986 — [PATCH v3 4/5] tty: Move serial8250_stop_rx in front of serial8250_start_tx

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-12 15:40 +0100
Subject[PATCH v3 4/5] tty: Move serial8250_stop_rx in front of serial8250_start_tx
Message-ID<qu1cC-1EX-21@gated-at.bofh.it>
In reply to#1267984
Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
---
 drivers/tty/serial/8250/8250_port.c | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 067ef55..3f6d8a2 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1286,6 +1286,19 @@ static void autoconfig_irq(struct uart_8250_port *up)
 	port->irq = (irq > 0) ? irq : 0;
 }
 
+static void serial8250_stop_rx(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+
+	serial8250_rpm_get(up);
+
+	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
+	up->port.read_status_mask &= ~UART_LSR_DR;
+	serial_port_out(port, UART_IER, up->ier);
+
+	serial8250_rpm_put(up);
+}
+
 static inline void __stop_tx(struct uart_8250_port *p)
 {
 	if (p->ier & UART_IER_THRI) {
@@ -1353,19 +1366,6 @@ static void serial8250_unthrottle(struct uart_port *port)
 	port->unthrottle(port);
 }
 
-static void serial8250_stop_rx(struct uart_port *port)
-{
-	struct uart_8250_port *up = up_to_u8250p(port);
-
-	serial8250_rpm_get(up);
-
-	up->ier &= ~(UART_IER_RLSI | UART_IER_RDI);
-	up->port.read_status_mask &= ~UART_LSR_DR;
-	serial_port_out(port, UART_IER, up->ier);
-
-	serial8250_rpm_put(up);
-}
-
 static void serial8250_disable_ms(struct uart_port *port)
 {
 	struct uart_8250_port *up =
-- 
2.6.2

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#1267987 — [PATCH v3 5/5] tty: Add software emulated RS485 support for 8250

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-12 15:40 +0100
Subject[PATCH v3 5/5] tty: Add software emulated RS485 support for 8250
Message-ID<qu1cC-1EX-19@gated-at.bofh.it>
In reply to#1267984
Implementation of software emulation of RS485 direction handling is based
on omap-serial driver.
Before and after transmission RTS is set to the appropriate value.

Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
---
 drivers/tty/serial/8250/8250_port.c | 152 ++++++++++++++++++++++++++++++++++--
 include/linux/serial_8250.h         |   2 +
 2 files changed, 148 insertions(+), 6 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 3f6d8a2..b863a12 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -37,6 +37,7 @@
 #include <linux/slab.h>
 #include <linux/uaccess.h>
 #include <linux/pm_runtime.h>
+#include <linux/timer.h>
 
 #include <asm/io.h>
 #include <asm/irq.h>
@@ -1299,7 +1300,75 @@ static void serial8250_stop_rx(struct uart_port *port)
 	serial8250_rpm_put(up);
 }
 
-static inline void __stop_tx(struct uart_8250_port *p)
+static inline void serial8250_rs485_set_rts_on_send(struct uart_8250_port *p)
+{
+	if (p->port.rs485.flags & SER_RS485_RTS_ON_SEND)
+		p->mcr |= UART_MCR_RTS;
+	else
+		p->mcr &= ~UART_MCR_RTS;
+	serial_out(p, UART_MCR, p->mcr);
+}
+
+static inline void serial8250_rs485_set_rts_after_send(struct uart_8250_port *p)
+{
+	if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
+		p->mcr |= UART_MCR_RTS;
+	else
+		p->mcr &= ~UART_MCR_RTS;
+	serial_out(p, UART_MCR, p->mcr);
+}
+
+static __u32 serial8250_rs485_start_tx(struct uart_8250_port *p)
+{
+	if (p->capabilities & UART_CAP_HW485 || !(p->port.rs485.flags & SER_RS485_ENABLED))
+		return 0;
+	
+	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX))
+		serial8250_stop_rx(&p->port);
+	
+	del_timer_sync(&p->rs485_stop_tx_timer);
+
+	if (!!(p->port.rs485.flags & SER_RS485_RTS_ON_SEND) != !!(p->mcr & UART_MCR_RTS)) {
+		serial8250_rs485_set_rts_on_send(p);
+		return p->port.rs485.delay_rts_before_send;
+	}
+
+	return 0;
+}
+
+static inline void __do_stop_tx_rs485(struct uart_8250_port *p)
+{
+	serial8250_rs485_set_rts_after_send(p);
+	/*
+	* Empty the RX FIFO, we are not interested in anything
+	* received during the half-duplex transmission.
+	*/
+	if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX))
+		serial8250_clear_fifos(p);
+}
+
+static void serial8250_handle_rs485_stop_tx_timer(unsigned long arg)
+{
+	struct uart_8250_port *p = (struct uart_8250_port*)arg;
+	__do_stop_tx_rs485(p);
+}
+
+static inline void __stop_tx_rs485(struct uart_8250_port *p)
+{
+	if (p->capabilities & UART_CAP_HW485 || !(p->port.rs485.flags & SER_RS485_ENABLED))
+		return;
+
+	del_timer_sync(&p->rs485_start_tx_timer);
+
+	/* __do_stop_tx_rs485 is going to set RTS according to config AND flush RX FIFO if required */
+	if (p->port.rs485.delay_rts_after_send > 0) {
+		mod_timer(&p->rs485_stop_tx_timer, jiffies + p->port.rs485.delay_rts_after_send * HZ / 1000);
+	} else {
+		__do_stop_tx_rs485(p);
+	}
+}
+
+static inline void __do_stop_tx(struct uart_8250_port *p)
 {
 	if (p->ier & UART_IER_THRI) {
 		p->ier &= ~UART_IER_THRI;
@@ -1308,6 +1377,12 @@ static inline void __stop_tx(struct uart_8250_port *p)
 	}
 }
 
+static inline void __stop_tx(struct uart_8250_port *p)
+{
+	__do_stop_tx(p);
+	__stop_tx_rs485(p);
+}
+
 static void serial8250_stop_tx(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
@@ -1325,12 +1400,10 @@ static void serial8250_stop_tx(struct uart_port *port)
 	serial8250_rpm_put(up);
 }
 
-static void serial8250_start_tx(struct uart_port *port)
+static inline void __start_tx(struct uart_port* port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 
-	serial8250_rpm_get_tx(up);
-
 	if (up->dma && !up->dma->tx_dma(up))
 		return;
 
@@ -1356,6 +1429,29 @@ static void serial8250_start_tx(struct uart_port *port)
 	}
 }
 
+static void serial8250_handle_rs485_start_tx_timer(unsigned long arg)
+{
+	struct uart_port* port = (struct uart_port*)arg;
+	__start_tx(port);
+}
+
+static void serial8250_start_tx(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	__u32 delay;
+	
+	serial8250_rpm_get_tx(up);
+
+	if (timer_pending(&up->rs485_start_tx_timer))
+		return;
+
+	if ((delay = serial8250_rs485_start_tx(up))) {
+		mod_timer(&up->rs485_start_tx_timer, jiffies + delay * HZ / 1000);
+	} else {
+		__start_tx(port);
+	}
+}
+
 static void serial8250_throttle(struct uart_port *port)
 {
 	port->throttle(port);
@@ -1806,6 +1902,16 @@ static void serial8250_put_poll_char(struct uart_port *port,
 
 #endif /* CONFIG_CONSOLE_POLL */
 
+static inline void serial8250_startup_rs485(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	
+	if (up->capabilities & UART_CAP_HW485 || !(up->port.rs485.flags & SER_RS485_ENABLED))
+		return;
+
+	serial8250_rs485_set_rts_after_send(up);
+}
+
 int serial8250_do_startup(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
@@ -2044,6 +2150,8 @@ dont_test_tx_en:
 		inb_p(icp);
 	}
 	retval = 0;
+
+	serial8250_startup_rs485(port);
 out:
 	serial8250_rpm_put(up);
 	return retval;
@@ -2057,12 +2165,24 @@ static int serial8250_startup(struct uart_port *port)
 	return serial8250_do_startup(port);
 }
 
+static inline void serial8250_shutdown_rs485(struct uart_port *port)
+{
+	struct uart_8250_port *up = up_to_u8250p(port);
+	
+	if (up->capabilities & UART_CAP_HW485 || !(up->port.rs485.flags & SER_RS485_ENABLED))
+		return;
+
+	del_timer_sync(&up->rs485_start_tx_timer);
+	del_timer_sync(&up->rs485_stop_tx_timer);
+}
+
 void serial8250_do_shutdown(struct uart_port *port)
 {
 	struct uart_8250_port *up = up_to_u8250p(port);
 	unsigned long flags;
 
 	serial8250_rpm_get(up);
+	serial8250_shutdown_rs485(port);
 	/*
 	 * Disable interrupts from this port
 	 */
@@ -2735,11 +2855,23 @@ serial8250_type(struct uart_port *port)
 	return uart_config[type].name;
 }
 
-static int serial8250_rs485_config(struct uart_port *port,
-				struct serial_rs485 *rs485)
+static int serial8250_rs485_config(struct uart_port *port, struct serial_rs485 *rs485)
 {
+	bool need_startup = false;
+
+	if (!(port->rs485.flags & SER_RS485_ENABLED) && (rs485->flags & SER_RS485_ENABLED)) {
+		need_startup = true;
+	}
+	if ((port->rs485.flags & SER_RS485_ENABLED) && !(rs485->flags & SER_RS485_ENABLED)) {
+		serial8250_shutdown_rs485(port);
+	}
+
 	port->rs485 = *rs485;
 	port->rs485.flags |= SER_RS485_SOFTWARE;
+
+	if (need_startup)
+		serial8250_startup_rs485(port);
+
 	return 0;
 }
 
@@ -2807,6 +2939,14 @@ void serial8250_set_defaults(struct uart_8250_port *up)
 	}
 
 	up->port.rs485_config = serial8250_rs485_config;
+	init_timer(&up->rs485_stop_tx_timer);
+	up->rs485_stop_tx_timer.function = serial8250_handle_rs485_stop_tx_timer;
+	up->rs485_stop_tx_timer.data = (unsigned long)up;
+	up->rs485_stop_tx_timer.flags |= TIMER_IRQSAFE;
+	init_timer(&up->rs485_start_tx_timer);
+	up->rs485_start_tx_timer.function = serial8250_handle_rs485_start_tx_timer;
+	up->rs485_start_tx_timer.data = (unsigned long)up;
+	up->rs485_start_tx_timer.flags |= TIMER_IRQSAFE;
 }
 EXPORT_SYMBOL_GPL(serial8250_set_defaults);
 
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index faa0e03..c4905e7 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -86,6 +86,8 @@ struct uart_8250_ops {
 struct uart_8250_port {
 	struct uart_port	port;
 	struct timer_list	timer;		/* "no irq" timer */
+	struct timer_list	rs485_start_tx_timer; /* "rs485 start tx" timer */
+	struct timer_list	rs485_stop_tx_timer; /* "rs485 stop tx" timer */
 	struct list_head	list;		/* ports on this IRQ */
 	unsigned short		capabilities;	/* port capabilities */
 	unsigned short		bugs;		/* port bugs */
-- 
2.6.2

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#1268001 — Re: [PATCH v3 5/5] tty: Add software emulated RS485 support for 8250

FromAndy Shevchenko <andy.shevchenko@gmail.com>
Date2015-11-12 15:50 +0100
SubjectRe: [PATCH v3 5/5] tty: Add software emulated RS485 support for 8250
Message-ID<qu1mi-1Ij-23@gated-at.bofh.it>
In reply to#1267987
On Thu, Nov 12, 2015 at 4:33 PM, Matwey V. Kornilov <matwey@sai.msu.ru> wrote:
> Implementation of software emulation of RS485 direction handling is based
> on omap-serial driver.
> Before and after transmission RTS is set to the appropriate value.
>

One comment below.

> Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
> ---
>  drivers/tty/serial/8250/8250_port.c | 152 ++++++++++++++++++++++++++++++++++--
>  include/linux/serial_8250.h         |   2 +
>  2 files changed, 148 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index 3f6d8a2..b863a12 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -37,6 +37,7 @@
>  #include <linux/slab.h>
>  #include <linux/uaccess.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/timer.h>
>
>  #include <asm/io.h>
>  #include <asm/irq.h>
> @@ -1299,7 +1300,75 @@ static void serial8250_stop_rx(struct uart_port *port)
>         serial8250_rpm_put(up);
>  }
>
> -static inline void __stop_tx(struct uart_8250_port *p)
> +static inline void serial8250_rs485_set_rts_on_send(struct uart_8250_port *p)
> +{
> +       if (p->port.rs485.flags & SER_RS485_RTS_ON_SEND)
> +               p->mcr |= UART_MCR_RTS;
> +       else
> +               p->mcr &= ~UART_MCR_RTS;
> +       serial_out(p, UART_MCR, p->mcr);
> +}
> +
> +static inline void serial8250_rs485_set_rts_after_send(struct uart_8250_port *p)
> +{
> +       if (p->port.rs485.flags & SER_RS485_RTS_AFTER_SEND)
> +               p->mcr |= UART_MCR_RTS;
> +       else
> +               p->mcr &= ~UART_MCR_RTS;
> +       serial_out(p, UART_MCR, p->mcr);
> +}
> +
> +static __u32 serial8250_rs485_start_tx(struct uart_8250_port *p)
> +{
> +       if (p->capabilities & UART_CAP_HW485 || !(p->port.rs485.flags & SER_RS485_ENABLED))
> +               return 0;
> +
> +       if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX))
> +               serial8250_stop_rx(&p->port);
> +
> +       del_timer_sync(&p->rs485_stop_tx_timer);
> +
> +       if (!!(p->port.rs485.flags & SER_RS485_RTS_ON_SEND) != !!(p->mcr & UART_MCR_RTS)) {
> +               serial8250_rs485_set_rts_on_send(p);
> +               return p->port.rs485.delay_rts_before_send;
> +       }
> +
> +       return 0;
> +}
> +
> +static inline void __do_stop_tx_rs485(struct uart_8250_port *p)
> +{
> +       serial8250_rs485_set_rts_after_send(p);
> +       /*
> +       * Empty the RX FIFO, we are not interested in anything
> +       * received during the half-duplex transmission.
> +       */
> +       if (!(p->port.rs485.flags & SER_RS485_RX_DURING_TX))
> +               serial8250_clear_fifos(p);
> +}
> +
> +static void serial8250_handle_rs485_stop_tx_timer(unsigned long arg)
> +{
> +       struct uart_8250_port *p = (struct uart_8250_port*)arg;
> +       __do_stop_tx_rs485(p);
> +}
> +
> +static inline void __stop_tx_rs485(struct uart_8250_port *p)
> +{
> +       if (p->capabilities & UART_CAP_HW485 || !(p->port.rs485.flags & SER_RS485_ENABLED))
> +               return;

It seems you are using this pattern three times. What about

static inline bool is_rs485_sw_enabled(struct uart_8250_port *p)
{
      return !(p->capabilities & UART_CAP_HW485) &&
(p->port.rs485.flags & SER_RS485_ENABLED);
}

> +
> +       del_timer_sync(&p->rs485_start_tx_timer);
> +
> +       /* __do_stop_tx_rs485 is going to set RTS according to config AND flush RX FIFO if required */
> +       if (p->port.rs485.delay_rts_after_send > 0) {
> +               mod_timer(&p->rs485_stop_tx_timer, jiffies + p->port.rs485.delay_rts_after_send * HZ / 1000);
> +       } else {
> +               __do_stop_tx_rs485(p);
> +       }
> +}
> +
> +static inline void __do_stop_tx(struct uart_8250_port *p)
>  {
>         if (p->ier & UART_IER_THRI) {
>                 p->ier &= ~UART_IER_THRI;
> @@ -1308,6 +1377,12 @@ static inline void __stop_tx(struct uart_8250_port *p)
>         }
>  }
>
> +static inline void __stop_tx(struct uart_8250_port *p)
> +{
> +       __do_stop_tx(p);
> +       __stop_tx_rs485(p);
> +}
> +
>  static void serial8250_stop_tx(struct uart_port *port)
>  {
>         struct uart_8250_port *up = up_to_u8250p(port);
> @@ -1325,12 +1400,10 @@ static void serial8250_stop_tx(struct uart_port *port)
>         serial8250_rpm_put(up);
>  }
>
> -static void serial8250_start_tx(struct uart_port *port)
> +static inline void __start_tx(struct uart_port* port)
>  {
>         struct uart_8250_port *up = up_to_u8250p(port);
>
> -       serial8250_rpm_get_tx(up);
> -
>         if (up->dma && !up->dma->tx_dma(up))
>                 return;
>
> @@ -1356,6 +1429,29 @@ static void serial8250_start_tx(struct uart_port *port)
>         }
>  }
>
> +static void serial8250_handle_rs485_start_tx_timer(unsigned long arg)
> +{
> +       struct uart_port* port = (struct uart_port*)arg;
> +       __start_tx(port);
> +}
> +
> +static void serial8250_start_tx(struct uart_port *port)
> +{
> +       struct uart_8250_port *up = up_to_u8250p(port);
> +       __u32 delay;
> +
> +       serial8250_rpm_get_tx(up);
> +
> +       if (timer_pending(&up->rs485_start_tx_timer))
> +               return;
> +
> +       if ((delay = serial8250_rs485_start_tx(up))) {
> +               mod_timer(&up->rs485_start_tx_timer, jiffies + delay * HZ / 1000);
> +       } else {
> +               __start_tx(port);
> +       }
> +}
> +
>  static void serial8250_throttle(struct uart_port *port)
>  {
>         port->throttle(port);
> @@ -1806,6 +1902,16 @@ static void serial8250_put_poll_char(struct uart_port *port,
>
>  #endif /* CONFIG_CONSOLE_POLL */
>
> +static inline void serial8250_startup_rs485(struct uart_port *port)
> +{
> +       struct uart_8250_port *up = up_to_u8250p(port);
> +
> +       if (up->capabilities & UART_CAP_HW485 || !(up->port.rs485.flags & SER_RS485_ENABLED))
> +               return;
> +
> +       serial8250_rs485_set_rts_after_send(up);
> +}
> +
>  int serial8250_do_startup(struct uart_port *port)
>  {
>         struct uart_8250_port *up = up_to_u8250p(port);
> @@ -2044,6 +2150,8 @@ dont_test_tx_en:
>                 inb_p(icp);
>         }
>         retval = 0;
> +
> +       serial8250_startup_rs485(port);
>  out:
>         serial8250_rpm_put(up);
>         return retval;
> @@ -2057,12 +2165,24 @@ static int serial8250_startup(struct uart_port *port)
>         return serial8250_do_startup(port);
>  }
>
> +static inline void serial8250_shutdown_rs485(struct uart_port *port)
> +{
> +       struct uart_8250_port *up = up_to_u8250p(port);
> +
> +       if (up->capabilities & UART_CAP_HW485 || !(up->port.rs485.flags & SER_RS485_ENABLED))
> +               return;
> +
> +       del_timer_sync(&up->rs485_start_tx_timer);
> +       del_timer_sync(&up->rs485_stop_tx_timer);
> +}
> +
>  void serial8250_do_shutdown(struct uart_port *port)
>  {
>         struct uart_8250_port *up = up_to_u8250p(port);
>         unsigned long flags;
>
>         serial8250_rpm_get(up);
> +       serial8250_shutdown_rs485(port);
>         /*
>          * Disable interrupts from this port
>          */
> @@ -2735,11 +2855,23 @@ serial8250_type(struct uart_port *port)
>         return uart_config[type].name;
>  }
>
> -static int serial8250_rs485_config(struct uart_port *port,
> -                               struct serial_rs485 *rs485)
> +static int serial8250_rs485_config(struct uart_port *port, struct serial_rs485 *rs485)
>  {
> +       bool need_startup = false;
> +
> +       if (!(port->rs485.flags & SER_RS485_ENABLED) && (rs485->flags & SER_RS485_ENABLED)) {
> +               need_startup = true;
> +       }
> +       if ((port->rs485.flags & SER_RS485_ENABLED) && !(rs485->flags & SER_RS485_ENABLED)) {
> +               serial8250_shutdown_rs485(port);
> +       }
> +
>         port->rs485 = *rs485;
>         port->rs485.flags |= SER_RS485_SOFTWARE;
> +
> +       if (need_startup)
> +               serial8250_startup_rs485(port);
> +
>         return 0;
>  }
>
> @@ -2807,6 +2939,14 @@ void serial8250_set_defaults(struct uart_8250_port *up)
>         }
>
>         up->port.rs485_config = serial8250_rs485_config;
> +       init_timer(&up->rs485_stop_tx_timer);
> +       up->rs485_stop_tx_timer.function = serial8250_handle_rs485_stop_tx_timer;
> +       up->rs485_stop_tx_timer.data = (unsigned long)up;
> +       up->rs485_stop_tx_timer.flags |= TIMER_IRQSAFE;
> +       init_timer(&up->rs485_start_tx_timer);
> +       up->rs485_start_tx_timer.function = serial8250_handle_rs485_start_tx_timer;
> +       up->rs485_start_tx_timer.data = (unsigned long)up;
> +       up->rs485_start_tx_timer.flags |= TIMER_IRQSAFE;
>  }
>  EXPORT_SYMBOL_GPL(serial8250_set_defaults);
>
> diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
> index faa0e03..c4905e7 100644
> --- a/include/linux/serial_8250.h
> +++ b/include/linux/serial_8250.h
> @@ -86,6 +86,8 @@ struct uart_8250_ops {
>  struct uart_8250_port {
>         struct uart_port        port;
>         struct timer_list       timer;          /* "no irq" timer */
> +       struct timer_list       rs485_start_tx_timer; /* "rs485 start tx" timer */
> +       struct timer_list       rs485_stop_tx_timer; /* "rs485 stop tx" timer */
>         struct list_head        list;           /* ports on this IRQ */
>         unsigned short          capabilities;   /* port capabilities */
>         unsigned short          bugs;           /* port bugs */
> --
> 2.6.2
>
> --
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-- 
With Best Regards,
Andy Shevchenko
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#1267989 — [PATCH v3 1/5] tty: Introduce UART_CAP_HW485

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-12 15:40 +0100
Subject[PATCH v3 1/5] tty: Introduce UART_CAP_HW485
Message-ID<qu1cD-1EX-27@gated-at.bofh.it>
In reply to#1267984
Introduce new capability UART_CAP_HW485 to mark 8250 UARTs which have
hardware support of line direction control.

Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
---
 drivers/tty/serial/8250/8250.h         | 1 +
 drivers/tty/serial/8250/8250_fintek.c  | 1 +
 drivers/tty/serial/8250/8250_lpc18xx.c | 1 +
 drivers/tty/serial/8250/8250_pci.c     | 1 +
 4 files changed, 4 insertions(+)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index d54dcd8..92a4f47 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -69,6 +69,7 @@ struct serial8250_config {
 	unsigned int	flags;
 };
 
+#define UART_CAP_HW485	(1 << 7)	/* UART has hardware direction control for RS485 */
 #define UART_CAP_FIFO	(1 << 8)	/* UART has FIFO */
 #define UART_CAP_EFR	(1 << 9)	/* UART has EFR */
 #define UART_CAP_SLEEP	(1 << 10)	/* UART has IER sleep */
diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index 8947439..f2831a8 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -208,6 +208,7 @@ fintek_8250_probe(struct pnp_dev *dev, const struct pnp_device_id *dev_id)
 	uart.port.iobase = pnp_port_start(dev, 0);
 	uart.port.iotype = UPIO_PORT;
 	uart.port.rs485_config = fintek_8250_rs485_config;
+	uart.capabilities = UART_CAP_HW485;
 
 	uart.port.flags |= UPF_SKIP_TEST | UPF_BOOT_AUTOCONF;
 	if (pnp_irq_flags(dev, 0) & IORESOURCE_IRQ_SHAREABLE)
diff --git a/drivers/tty/serial/8250/8250_lpc18xx.c b/drivers/tty/serial/8250/8250_lpc18xx.c
index 99cd478..9d30276 100644
--- a/drivers/tty/serial/8250/8250_lpc18xx.c
+++ b/drivers/tty/serial/8250/8250_lpc18xx.c
@@ -175,6 +175,7 @@ static int lpc18xx_serial_probe(struct platform_device *pdev)
 	uart.port.private_data = data;
 	uart.port.rs485_config = lpc18xx_rs485_config;
 	uart.port.serial_out = lpc18xx_uart_serial_out;
+	uart.capabilities = UART_CAP_HW485;
 
 	uart.dma = &data->dma;
 	uart.dma->rxconf.src_maxburst = 1;
diff --git a/drivers/tty/serial/8250/8250_pci.c b/drivers/tty/serial/8250/8250_pci.c
index 4097f3f..c7c0ae9 100644
--- a/drivers/tty/serial/8250/8250_pci.c
+++ b/drivers/tty/serial/8250/8250_pci.c
@@ -1599,6 +1599,7 @@ static int pci_fintek_setup(struct serial_private *priv,
 	port->port.iotype = UPIO_PORT;
 	port->port.iobase = iobase;
 	port->port.rs485_config = pci_fintek_rs485_config;
+	port->capabilities = UART_CAP_HW485;
 
 	data = devm_kzalloc(&pdev->dev, sizeof(u8), GFP_KERNEL);
 	if (!data)
-- 
2.6.2

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#1267990 — [PATCH v3 3/5] tty: Implement default fallback serial8250_rs485_config

From"Matwey V. Kornilov" <matwey@sai.msu.ru>
Date2015-11-12 15:40 +0100
Subject[PATCH v3 3/5] tty: Implement default fallback serial8250_rs485_config
Message-ID<qu1cD-1EX-31@gated-at.bofh.it>
In reply to#1267984
When 8250 driver doesn't have its own hardware RS485 support and doesn't
want to override rs485_config callback, then default
serial8250_rs485_config is used. It just stores supplied by user-space
config and sets SER_RS485_SOFTWARE

Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
---
 drivers/tty/serial/8250/8250_core.c |  3 ++-
 drivers/tty/serial/8250/8250_port.c | 10 ++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 3912646..71fabb0 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -986,7 +986,6 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
 		uart->capabilities	= up->capabilities;
 		uart->port.throttle	= up->port.throttle;
 		uart->port.unthrottle	= up->port.unthrottle;
-		uart->port.rs485_config	= up->port.rs485_config;
 		uart->port.rs485	= up->port.rs485;
 		uart->dma		= up->dma;
 
@@ -1025,6 +1024,8 @@ int serial8250_register_8250_port(struct uart_8250_port *up)
 			uart->port.pm = up->port.pm;
 		if (up->port.handle_break)
 			uart->port.handle_break = up->port.handle_break;
+		if (up->port.rs485_config)
+			uart->port.rs485_config	= up->port.rs485_config;
 		if (up->dl_read)
 			uart->dl_read = up->dl_read;
 		if (up->dl_write)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 52d82d2..067ef55 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -2735,6 +2735,14 @@ serial8250_type(struct uart_port *port)
 	return uart_config[type].name;
 }
 
+static int serial8250_rs485_config(struct uart_port *port,
+				struct serial_rs485 *rs485)
+{
+	port->rs485 = *rs485;
+	port->rs485.flags |= SER_RS485_SOFTWARE;
+	return 0;
+}
+
 static const struct uart_ops serial8250_pops = {
 	.tx_empty	= serial8250_tx_empty,
 	.set_mctrl	= serial8250_set_mctrl,
@@ -2797,6 +2805,8 @@ void serial8250_set_defaults(struct uart_8250_port *up)
 		if (!up->dma->rx_dma)
 			up->dma->rx_dma = serial8250_rx_dma;
 	}
+
+	up->port.rs485_config = serial8250_rs485_config;
 }
 EXPORT_SYMBOL_GPL(serial8250_set_defaults);
 
-- 
2.6.2

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