* [PATCH v3 01/12] serial: Store character timing information to uart_port
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 10:52 ` Andy Shevchenko
2022-04-11 8:33 ` [PATCH v3 02/12] serial: 8250: Handle UART without interrupt on TEMT Ilpo Järvinen
` (11 subsequent siblings)
12 siblings, 1 reply; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen
Struct uart_port currently stores FIFO timeout. Having character
timing information readily available is useful. Even serial core
itself determines char_time from port->timeout using inverse
calculation.
Store frame_time directly into uart_port. Character time is stored
in nanoseconds to have reasonable precision with high rates.
To avoid overflow, 64-bit math is necessary.
It might be possible to determine timeout from frame_time by
multiplying it with fifosize as needed but only part of the
users seem to be protected by a lock. Thus, this patch does
not pursue storing only frame_time in uart_port.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/serial_core.c | 14 ++++++++------
include/linux/serial_core.h | 1 +
2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 846192a7b4bf..c6ac91033e38 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -24,6 +24,7 @@
#include <linux/sysrq.h>
#include <linux/delay.h>
#include <linux/mutex.h>
+#include <linux/math64.h>
#include <linux/security.h>
#include <linux/irq.h>
@@ -333,15 +334,18 @@ void
uart_update_timeout(struct uart_port *port, unsigned int cflag,
unsigned int baud)
{
- unsigned int size;
+ unsigned int size = tty_get_frame_size(cflag);
+ u64 frame_time;
- size = tty_get_frame_size(cflag) * port->fifosize;
+ frame_time = (u64)size * NSEC_PER_SEC;
+ size *= port->fifosize;
/*
* Figure the timeout to send the above number of bits.
* Add .02 seconds of slop
*/
port->timeout = (HZ * size) / baud + HZ/50;
+ port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
}
EXPORT_SYMBOL(uart_update_timeout);
@@ -1596,10 +1600,8 @@ static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
* Note: we have to use pretty tight timings here to satisfy
* the NIST-PCTS.
*/
- char_time = (port->timeout - HZ/50) / port->fifosize;
- char_time = char_time / 5;
- if (char_time == 0)
- char_time = 1;
+ char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
+
if (timeout && timeout < char_time)
char_time = timeout;
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 31f7fe527395..504d365e2803 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -232,6 +232,7 @@ struct uart_port {
int hw_stopped; /* sw-assisted CTS flow state */
unsigned int mctrl; /* current modem ctrl settings */
unsigned int timeout; /* character-based timeout */
+ unsigned int frame_time; /* frame timing in ns */
unsigned int type; /* port type */
const struct uart_ops *ops;
unsigned int custom_divisor;
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* Re: [PATCH v3 01/12] serial: Store character timing information to uart_port
2022-04-11 8:33 ` [PATCH v3 01/12] serial: Store character timing information to uart_port Ilpo Järvinen
@ 2022-04-11 10:52 ` Andy Shevchenko
2022-04-11 10:56 ` Andy Shevchenko
0 siblings, 1 reply; 30+ messages in thread
From: Andy Shevchenko @ 2022-04-11 10:52 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Johan Hovold,
heiko, giulio.benetti, Heikki Krogerus, Uwe Kleine-König
On Mon, Apr 11, 2022 at 11:33:10AM +0300, Ilpo Järvinen wrote:
> Struct uart_port currently stores FIFO timeout. Having character
> timing information readily available is useful. Even serial core
> itself determines char_time from port->timeout using inverse
> calculation.
>
> Store frame_time directly into uart_port. Character time is stored
> in nanoseconds to have reasonable precision with high rates.
> To avoid overflow, 64-bit math is necessary.
>
> It might be possible to determine timeout from frame_time by
> multiplying it with fifosize as needed but only part of the
> users seem to be protected by a lock. Thus, this patch does
> not pursue storing only frame_time in uart_port.
...
> - char_time = (port->timeout - HZ/50) / port->fifosize;
> - char_time = char_time / 5;
> - if (char_time == 0)
> - char_time = 1;
> + char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
> +
> if (timeout && timeout < char_time)
> char_time = timeout;
Seems it can be packed to something like
char_time = min_not_zero(nsecs_to_jiffies(port->frame_time / 5), timeout);
?
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v3 01/12] serial: Store character timing information to uart_port
2022-04-11 10:52 ` Andy Shevchenko
@ 2022-04-11 10:56 ` Andy Shevchenko
2022-04-11 11:00 ` Andy Shevchenko
0 siblings, 1 reply; 30+ messages in thread
From: Andy Shevchenko @ 2022-04-11 10:56 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Johan Hovold,
heiko, giulio.benetti, Heikki Krogerus, Uwe Kleine-König
On Mon, Apr 11, 2022 at 01:52:18PM +0300, Andy Shevchenko wrote:
> On Mon, Apr 11, 2022 at 11:33:10AM +0300, Ilpo Järvinen wrote:
> > Struct uart_port currently stores FIFO timeout. Having character
> > timing information readily available is useful. Even serial core
> > itself determines char_time from port->timeout using inverse
> > calculation.
> >
> > Store frame_time directly into uart_port. Character time is stored
> > in nanoseconds to have reasonable precision with high rates.
> > To avoid overflow, 64-bit math is necessary.
> >
> > It might be possible to determine timeout from frame_time by
> > multiplying it with fifosize as needed but only part of the
> > users seem to be protected by a lock. Thus, this patch does
> > not pursue storing only frame_time in uart_port.
...
> > - char_time = (port->timeout - HZ/50) / port->fifosize;
> > - char_time = char_time / 5;
> > - if (char_time == 0)
> > - char_time = 1;
> > + char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
> > +
> > if (timeout && timeout < char_time)
> > char_time = timeout;
>
> Seems it can be packed to something like
>
> char_time = min_not_zero(nsecs_to_jiffies(port->frame_time / 5), timeout);
>
> ?
Actually:
char_time = min_not_zero(timeout, nsecs_to_jiffies(port->frame_time / 5));
Ah, either way it would still miss the case when both == 0. So, we need
something like minmax3_not_zero, where 1UL is implied argument. Probably
a suggesting for the future, since here it doesn't make much sense to
introduce.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v3 01/12] serial: Store character timing information to uart_port
2022-04-11 10:56 ` Andy Shevchenko
@ 2022-04-11 11:00 ` Andy Shevchenko
0 siblings, 0 replies; 30+ messages in thread
From: Andy Shevchenko @ 2022-04-11 11:00 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Johan Hovold,
heiko, giulio.benetti, Heikki Krogerus, Uwe Kleine-König
On Mon, Apr 11, 2022 at 01:56:24PM +0300, Andy Shevchenko wrote:
> On Mon, Apr 11, 2022 at 01:52:18PM +0300, Andy Shevchenko wrote:
> > On Mon, Apr 11, 2022 at 11:33:10AM +0300, Ilpo Järvinen wrote:
> > > Struct uart_port currently stores FIFO timeout. Having character
> > > timing information readily available is useful. Even serial core
> > > itself determines char_time from port->timeout using inverse
> > > calculation.
> > >
> > > Store frame_time directly into uart_port. Character time is stored
> > > in nanoseconds to have reasonable precision with high rates.
> > > To avoid overflow, 64-bit math is necessary.
> > >
> > > It might be possible to determine timeout from frame_time by
> > > multiplying it with fifosize as needed but only part of the
> > > users seem to be protected by a lock. Thus, this patch does
> > > not pursue storing only frame_time in uart_port.
>
> ...
>
> > > - char_time = (port->timeout - HZ/50) / port->fifosize;
> > > - char_time = char_time / 5;
> > > - if (char_time == 0)
> > > - char_time = 1;
> > > + char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
> > > +
> > > if (timeout && timeout < char_time)
> > > char_time = timeout;
> >
> > Seems it can be packed to something like
> >
> > char_time = min_not_zero(nsecs_to_jiffies(port->frame_time / 5), timeout);
> >
> > ?
>
> Actually:
>
> char_time = min_not_zero(timeout, nsecs_to_jiffies(port->frame_time / 5));
>
> Ah, either way it would still miss the case when both == 0. So, we need
> something like minmax3_not_zero, where 1UL is implied argument. Probably
> a suggesting for the future, since here it doesn't make much sense to
> introduce.
In case somebody goes for it:
#define minmax_not_zero(x, y) (min_not_zero(x, y) ?: 1)
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v3 02/12] serial: 8250: Handle UART without interrupt on TEMT
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 01/12] serial: Store character timing information to uart_port Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 03/12] serial: 8250_dwlib: RS485 HW half & full duplex support Ilpo Järvinen
` (10 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, Eric Tremblay
Add UART_CAP_NOTEMT for UARTs that lack interrupt on TEMT but
want to use em485. Em485 framework needs to ensure not only
FIFO is empty but also that tx shift register is empty.
This approach uses Uwe Kleine-König's suggestion on simply
using/incrementing stop_tx timer rather than adding another
timer. When UART_CAP_NOTEMT is set and THRE is present w/o
TEMT, stop tx timer is reused to wait for the emptying of
the shift register.
Suggested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Cc: Eric Tremblay <etremblay@distech-controls.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250.h | 1 +
drivers/tty/serial/8250/8250_port.c | 28 +++++++++++++++++++---------
2 files changed, 20 insertions(+), 9 deletions(-)
diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index db784ace25d8..100426cd2335 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -83,6 +83,7 @@ struct serial8250_config {
#define UART_CAP_MINI BIT(17) /* Mini UART on BCM283X family lacks:
* STOP PARITY EPAR SPAR WLEN5 WLEN6
*/
+#define UART_CAP_NOTEMT BIT(18) /* UART cannot interrupt on TEMT */
#define UART_BUG_QUOT BIT(0) /* UART has buggy quot LSB */
#define UART_BUG_TXEN BIT(1) /* UART has buggy TX IIR status */
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index d30a6c1c4c20..276c5281aaa0 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1504,18 +1504,19 @@ static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL);
}
-static void __stop_tx_rs485(struct uart_8250_port *p)
+static void __stop_tx_rs485(struct uart_8250_port *p, u64 stop_delay)
{
struct uart_8250_em485 *em485 = p->em485;
+ stop_delay += (u64)p->port.rs485.delay_rts_after_send * NSEC_PER_USEC;
+
/*
* rs485_stop_tx() is going to set RTS according to config
* AND flush RX FIFO if required.
*/
- if (p->port.rs485.delay_rts_after_send > 0) {
+ if (stop_delay > 0) {
em485->active_timer = &em485->stop_tx_timer;
- start_hrtimer_ms(&em485->stop_tx_timer,
- p->port.rs485.delay_rts_after_send);
+ hrtimer_start(&em485->stop_tx_timer, ns_to_ktime(stop_delay), HRTIMER_MODE_REL);
} else {
p->rs485_stop_tx(p);
em485->active_timer = NULL;
@@ -1535,16 +1536,25 @@ static inline void __stop_tx(struct uart_8250_port *p)
if (em485) {
unsigned char lsr = serial_in(p, UART_LSR);
+ u64 stop_delay = 0;
+
+ if (!(lsr & UART_LSR_THRE))
+ return;
/*
* To provide required timeing and allow FIFO transfer,
* __stop_tx_rs485() must be called only when both FIFO and
- * shift register are empty. It is for device driver to enable
- * interrupt on TEMT.
+ * shift register are empty. The device driver should either
+ * enable interrupt on TEMT or set UART_CAP_NOTEMT that will
+ * enlarge stop_tx_timer by the tx time of one frame to cover
+ * for emptying of the shift register.
*/
- if ((lsr & BOTH_EMPTY) != BOTH_EMPTY)
- return;
+ if (!(lsr & UART_LSR_TEMT)) {
+ if (!(p->capabilities & UART_CAP_NOTEMT))
+ return;
+ stop_delay = p->port.frame_time;
+ }
- __stop_tx_rs485(p);
+ __stop_tx_rs485(p, stop_delay);
}
__do_stop_tx(p);
}
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 03/12] serial: 8250_dwlib: RS485 HW half & full duplex support
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 01/12] serial: Store character timing information to uart_port Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 02/12] serial: 8250: Handle UART without interrupt on TEMT Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 04/12] serial: 8250_dwlib: Implement SW half " Ilpo Järvinen
` (9 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, Raymond Tan
The Synopsys DesignWare UART can be configured to have HW
support for the RS485 protocol from IP version 4.0 onward.
Add support for hardware-controlled half duplex and full
duplex modes.
HW will take care of managing DE and RE, the driver just gives
it permission to use either by setting both to 1.
To ask for full duplex mode, userspace sets SER_RS485_RX_DURING_TX
flag and HW will take care of the rest.
Set delay_rts_before_send and delay_rts_after_send to zero for now.
The granularity of that ABI is too coarse to be useful.
Co-developed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Co-developed-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250_dwlib.c | 85 +++++++++++++++++++++++++++-
drivers/tty/serial/8250/8250_dwlib.h | 3 +
2 files changed, 86 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
index 622d3b0d89e7..08432e2fe511 100644
--- a/drivers/tty/serial/8250/8250_dwlib.c
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -2,19 +2,33 @@
/* Synopsys DesignWare 8250 library. */
#include <linux/bitops.h>
+#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
+#include <linux/property.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
#include "8250_dwlib.h"
/* Offsets for the DesignWare specific registers */
+#define DW_UART_TCR 0xac /* Transceiver Control Register (RS485) */
+#define DW_UART_DE_EN 0xb0 /* Driver Output Enable Register */
+#define DW_UART_RE_EN 0xb4 /* Receiver Output Enable Register */
#define DW_UART_DLF 0xc0 /* Divisor Latch Fraction Register */
#define DW_UART_CPR 0xf4 /* Component Parameter Register */
#define DW_UART_UCV 0xf8 /* UART Component Version */
+/* Transceiver Control Register bits */
+#define DW_UART_TCR_RS485_EN BIT(0)
+#define DW_UART_TCR_RE_POL BIT(1)
+#define DW_UART_TCR_DE_POL BIT(2)
+#define DW_UART_TCR_XFER_MODE GENMASK(4, 3)
+#define DW_UART_TCR_XFER_MODE_DE_DURING_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 0)
+#define DW_UART_TCR_XFER_MODE_SW_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 1)
+#define DW_UART_TCR_XFER_MODE_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 2)
+
/* Component Parameter Register bits */
#define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0)
#define DW_UART_CPR_AFCE_MODE (1 << 4)
@@ -87,11 +101,80 @@ void dw8250_do_set_termios(struct uart_port *p, struct ktermios *termios, struct
}
EXPORT_SYMBOL_GPL(dw8250_do_set_termios);
+static int dw8250_rs485_config(struct uart_port *p, struct serial_rs485 *rs485)
+{
+ u32 tcr;
+
+ tcr = dw8250_readl_ext(p, DW_UART_TCR);
+ tcr &= ~DW_UART_TCR_XFER_MODE;
+
+ if (rs485->flags & SER_RS485_ENABLED) {
+ /* Clear unsupported flags. */
+ rs485->flags &= SER_RS485_ENABLED | SER_RS485_RX_DURING_TX |
+ SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND;
+ tcr |= DW_UART_TCR_RS485_EN;
+
+ if (rs485->flags & SER_RS485_RX_DURING_TX) {
+ tcr |= DW_UART_TCR_XFER_MODE_DE_DURING_RE;
+ } else {
+ /* HW does not support same DE level for tx and rx */
+ if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
+ !(rs485->flags & SER_RS485_RTS_AFTER_SEND))
+ return -EINVAL;
+
+ tcr |= DW_UART_TCR_XFER_MODE_DE_OR_RE;
+ }
+ dw8250_writel_ext(p, DW_UART_DE_EN, 1);
+ dw8250_writel_ext(p, DW_UART_RE_EN, 1);
+ } else {
+ rs485->flags = 0;
+
+ tcr &= ~DW_UART_TCR_RS485_EN;
+ }
+
+ /* Reset to default polarity */
+ tcr |= DW_UART_TCR_DE_POL;
+ tcr &= ~DW_UART_TCR_RE_POL;
+
+ if (!(rs485->flags & SER_RS485_RTS_ON_SEND))
+ tcr &= ~DW_UART_TCR_DE_POL;
+ if (device_property_read_bool(p->dev, "rs485-rx-active-high"))
+ tcr |= DW_UART_TCR_RE_POL;
+
+ dw8250_writel_ext(p, DW_UART_TCR, tcr);
+
+ rs485->delay_rts_before_send = 0;
+ rs485->delay_rts_after_send = 0;
+
+ p->rs485 = *rs485;
+
+ return 0;
+}
+
+/*
+ * Tests if RE_EN register can have non-zero value to see if RS-485 HW support
+ * is present.
+ */
+static bool dw8250_detect_rs485_hw(struct uart_port *p)
+{
+ u32 reg;
+
+ dw8250_writel_ext(p, DW_UART_RE_EN, 1);
+ reg = dw8250_readl_ext(p, DW_UART_RE_EN);
+ dw8250_writel_ext(p, DW_UART_RE_EN, 0);
+ return reg;
+}
+
void dw8250_setup_port(struct uart_port *p)
{
+ struct dw8250_port_data *d = p->private_data;
struct uart_8250_port *up = up_to_u8250p(p);
u32 reg;
+ d->hw_rs485_support = dw8250_detect_rs485_hw(p);
+ if (d->hw_rs485_support)
+ p->rs485_config = dw8250_rs485_config;
+
/*
* If the Component Version Register returns zero, we know that
* ADDITIONAL_FEATURES are not enabled. No need to go any further.
@@ -108,8 +191,6 @@ void dw8250_setup_port(struct uart_port *p)
dw8250_writel_ext(p, DW_UART_DLF, 0);
if (reg) {
- struct dw8250_port_data *d = p->private_data;
-
d->dlf_size = fls(reg);
p->get_divisor = dw8250_get_divisor;
p->set_divisor = dw8250_set_divisor;
diff --git a/drivers/tty/serial/8250/8250_dwlib.h b/drivers/tty/serial/8250/8250_dwlib.h
index 83d528e5cc21..a8fa020ca544 100644
--- a/drivers/tty/serial/8250/8250_dwlib.h
+++ b/drivers/tty/serial/8250/8250_dwlib.h
@@ -14,6 +14,9 @@ struct dw8250_port_data {
/* Hardware configuration */
u8 dlf_size;
+
+ /* RS485 variables */
+ bool hw_rs485_support;
};
void dw8250_do_set_termios(struct uart_port *p, struct ktermios *termios, struct ktermios *old);
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 04/12] serial: 8250_dwlib: Implement SW half duplex support
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (2 preceding siblings ...)
2022-04-11 8:33 ` [PATCH v3 03/12] serial: 8250_dwlib: RS485 HW half & full duplex support Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 05/12] dt_bindings: rs485: Add receiver enable polarity Ilpo Järvinen
` (8 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, Eric Tremblay
This patch enables support for SW half-duplex mode using em485.
Cc: Eric Tremblay <etremblay@distech-controls.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250_dwlib.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
index 08432e2fe511..04852af4c024 100644
--- a/drivers/tty/serial/8250/8250_dwlib.c
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -172,8 +172,14 @@ void dw8250_setup_port(struct uart_port *p)
u32 reg;
d->hw_rs485_support = dw8250_detect_rs485_hw(p);
- if (d->hw_rs485_support)
+ if (d->hw_rs485_support) {
p->rs485_config = dw8250_rs485_config;
+ } else {
+ p->rs485_config = serial8250_em485_config;
+ up->rs485_start_tx = serial8250_em485_start_tx;
+ up->rs485_stop_tx = serial8250_em485_stop_tx;
+ }
+ up->capabilities |= UART_CAP_NOTEMT;
/*
* If the Component Version Register returns zero, we know that
@@ -205,7 +211,7 @@ void dw8250_setup_port(struct uart_port *p)
p->type = PORT_16550A;
p->flags |= UPF_FIXED_TYPE;
p->fifosize = DW_UART_CPR_FIFO_SIZE(reg);
- up->capabilities = UART_CAP_FIFO;
+ up->capabilities = UART_CAP_FIFO | UART_CAP_NOTEMT;
}
if (reg & DW_UART_CPR_AFCE_MODE)
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 05/12] dt_bindings: rs485: Add receiver enable polarity
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (3 preceding siblings ...)
2022-04-11 8:33 ` [PATCH v3 04/12] serial: 8250_dwlib: Implement SW half " Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 06/12] ACPI / property: Document RS485 _DSD properties Ilpo Järvinen
` (7 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, devicetree,
Rob Herring
Add polarity property for receiver enable. Some UARTs have
separate enable pins for tx (RTS or DE) and rx (RE). As most
RS485 transceivers have !RE pin, the default is active low in
contrast to rs485-rts-active-low that defaults to active high.
Cc: devicetree@vger.kernel.org
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
Documentation/devicetree/bindings/serial/rs485.yaml | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/Documentation/devicetree/bindings/serial/rs485.yaml b/Documentation/devicetree/bindings/serial/rs485.yaml
index 0c9fa694f85c..f2c9c9fe6aa7 100644
--- a/Documentation/devicetree/bindings/serial/rs485.yaml
+++ b/Documentation/devicetree/bindings/serial/rs485.yaml
@@ -33,6 +33,11 @@ properties:
description: drive RTS low when sending (default is high).
$ref: /schemas/types.yaml#/definitions/flag
+ rs485-rx-active-high:
+ description: Polarity of receiver enable signal (when separate from RTS).
+ True indicates active high (default is low).
+ $ref: /schemas/types.yaml#/definitions/flag
+
linux,rs485-enabled-at-boot-time:
description: enables the rs485 feature at boot time. It can be disabled
later with proper ioctl.
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 06/12] ACPI / property: Document RS485 _DSD properties
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (4 preceding siblings ...)
2022-04-11 8:33 ` [PATCH v3 05/12] dt_bindings: rs485: Add receiver enable polarity Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 11:02 ` Andy Shevchenko
2022-04-11 8:33 ` Ilpo Järvinen
` (6 subsequent siblings)
12 siblings, 1 reply; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen
Document RS485 related properties returned from ACPI _DSD
as device properties.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
.../firmware-guide/acpi/enumeration.rst | 25 +++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst
index 74b830b2fd59..b42017bf789e 100644
--- a/Documentation/firmware-guide/acpi/enumeration.rst
+++ b/Documentation/firmware-guide/acpi/enumeration.rst
@@ -374,6 +374,31 @@ descriptors once the device is released.
See Documentation/firmware-guide/acpi/gpio-properties.rst for more information
about the _DSD binding related to GPIOs.
+RS-485 support
+==============
+
+ACPI _DSD (Device Specific Data) can be used to describe RS-485 capability
+of UART.
+
+For example::
+
+ Device (DEV)
+ {
+ ...
+
+ // ACPI 5.1 _DSD used for RS-485 capabilities
+ Name (_DSD, Package ()
+ {
+ ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
+ Package ()
+ {
+ Package () {"rs485-rts-active-low", Zero},
+ Package () {"rs485-rx-active-high", Zero},
+ Package () {"rs485-rx-during-tx", Zero},
+ }
+ })
+ ...
+
MFD devices
===========
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* Re: [PATCH v3 06/12] ACPI / property: Document RS485 _DSD properties
2022-04-11 8:33 ` [PATCH v3 06/12] ACPI / property: Document RS485 _DSD properties Ilpo Järvinen
@ 2022-04-11 11:02 ` Andy Shevchenko
0 siblings, 0 replies; 30+ messages in thread
From: Andy Shevchenko @ 2022-04-11 11:02 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Johan Hovold,
heiko, giulio.benetti, Heikki Krogerus, Uwe Kleine-König
On Mon, Apr 11, 2022 at 11:33:15AM +0300, Ilpo Järvinen wrote:
> Document RS485 related properties returned from ACPI _DSD
> as device properties.
...
> + Package () {"rs485-rts-active-low", Zero},
> + Package () {"rs485-rx-active-high", Zero},
> + Package () {"rs485-rx-during-tx", Zero},
Package () { "rs485-rts-active-low", Zero },
Package () { "rs485-rx-active-high", Zero },
Package () { "rs485-rx-during-tx", Zero },
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v3 07/12] serial: termbits: ADDRB to indicate 9th bit addressing mode
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 01/12] serial: Store character timing information to uart_port Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 03/12] serial: 8250_dwlib: RS485 HW half & full duplex support Ilpo Järvinen
` (10 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, linux-api,
Ivan Kokshaysky, Matt Turner, linux-alpha, Thomas Bogendoerfer,
linux-mips, James E.J. Bottomley, Helge Deller, linux-parisc,
Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
linuxppc-dev, David S. Miller, sparclinux, Arnd Bergmann,
linux-arch, linux-usb
Add ADDRB to termbits to indicate 9th bit addressing mode.
This change is necessary for supporting devices with RS485
multipoint addressing [*]. A later patch in the patch series
adds support for Synopsys Designware UART capable for 9th bit
addressing mode. In this mode, 9th bit is used to indicate an
address (byte) within the communication line. The 9th bit
addressing mode is selected using ADDRB introduced by an earlier
patch.
[*] 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.
Cc: linux-api@vger.kernel.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
arch/alpha/include/uapi/asm/termbits.h | 1 +
arch/mips/include/uapi/asm/termbits.h | 1 +
arch/parisc/include/uapi/asm/termbits.h | 1 +
arch/powerpc/include/uapi/asm/termbits.h | 1 +
arch/sparc/include/uapi/asm/termbits.h | 1 +
drivers/char/pcmcia/synclink_cs.c | 2 ++
drivers/ipack/devices/ipoctal.c | 2 ++
drivers/mmc/core/sdio_uart.c | 2 ++
drivers/net/usb/hso.c | 3 ++-
drivers/s390/char/tty3270.c | 3 +++
drivers/staging/greybus/uart.c | 2 ++
drivers/tty/amiserial.c | 6 +++++-
drivers/tty/moxa.c | 1 +
drivers/tty/mxser.c | 1 +
drivers/tty/serial/serial_core.c | 2 ++
drivers/tty/synclink_gt.c | 2 ++
drivers/tty/tty_ioctl.c | 2 ++
drivers/usb/class/cdc-acm.c | 2 ++
drivers/usb/serial/usb-serial.c | 6 ++++--
include/uapi/asm-generic/termbits.h | 1 +
net/bluetooth/rfcomm/tty.c | 2 ++
21 files changed, 40 insertions(+), 4 deletions(-)
diff --git a/arch/alpha/include/uapi/asm/termbits.h b/arch/alpha/include/uapi/asm/termbits.h
index 4575ba34a0ea..0c123e715486 100644
--- a/arch/alpha/include/uapi/asm/termbits.h
+++ b/arch/alpha/include/uapi/asm/termbits.h
@@ -180,6 +180,7 @@ struct ktermios {
#define HUPCL 00040000
#define CLOCAL 00100000
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/mips/include/uapi/asm/termbits.h b/arch/mips/include/uapi/asm/termbits.h
index dfeffba729b7..4732d31b0e4e 100644
--- a/arch/mips/include/uapi/asm/termbits.h
+++ b/arch/mips/include/uapi/asm/termbits.h
@@ -182,6 +182,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/parisc/include/uapi/asm/termbits.h b/arch/parisc/include/uapi/asm/termbits.h
index 40e920f8d683..d6bbd10d92ba 100644
--- a/arch/parisc/include/uapi/asm/termbits.h
+++ b/arch/parisc/include/uapi/asm/termbits.h
@@ -159,6 +159,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/powerpc/include/uapi/asm/termbits.h b/arch/powerpc/include/uapi/asm/termbits.h
index ed18bc61f63d..c6a033732f39 100644
--- a/arch/powerpc/include/uapi/asm/termbits.h
+++ b/arch/powerpc/include/uapi/asm/termbits.h
@@ -171,6 +171,7 @@ struct ktermios {
#define HUPCL 00040000
#define CLOCAL 00100000
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/sparc/include/uapi/asm/termbits.h b/arch/sparc/include/uapi/asm/termbits.h
index ce5ad5d0f105..5eb1d547b5c4 100644
--- a/arch/sparc/include/uapi/asm/termbits.h
+++ b/arch/sparc/include/uapi/asm/termbits.h
@@ -201,6 +201,7 @@ struct ktermios {
#define B3500000 0x00001012
#define B4000000 0x00001013 */
#define CIBAUD 0x100f0000 /* input baud rate (not used) */
+#define ADDRB 0x20000000 /* address bit */
#define CMSPAR 0x40000000 /* mark or space (stick) parity */
#define CRTSCTS 0x80000000 /* flow control */
diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c
index 78baba55a8b5..d179b9b57a25 100644
--- a/drivers/char/pcmcia/synclink_cs.c
+++ b/drivers/char/pcmcia/synclink_cs.c
@@ -2287,6 +2287,8 @@ static void mgslpc_set_termios(struct tty_struct *tty, struct ktermios *old_term
== RELEVANT_IFLAG(old_termios->c_iflag)))
return;
+ tty->termios.c_cflag &= ~ADDRB;
+
mgslpc_change_params(info, tty);
/* Handle transition to B0 status */
diff --git a/drivers/ipack/devices/ipoctal.c b/drivers/ipack/devices/ipoctal.c
index 20d2b9ec1227..d66cc9683ebc 100644
--- a/drivers/ipack/devices/ipoctal.c
+++ b/drivers/ipack/devices/ipoctal.c
@@ -506,6 +506,8 @@ static void ipoctal_set_termios(struct tty_struct *tty,
struct ipoctal_channel *channel = tty->driver_data;
speed_t baud;
+ tty->termios.c_cflag &= ~ADDRB;
+
cflag = tty->termios.c_cflag;
/* Disable and reset everything before change the setup */
diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c
index 04c0823e0359..7432b01379ef 100644
--- a/drivers/mmc/core/sdio_uart.c
+++ b/drivers/mmc/core/sdio_uart.c
@@ -880,6 +880,8 @@ static void sdio_uart_set_termios(struct tty_struct *tty,
if (sdio_uart_claim_func(port) != 0)
return;
+ tty->termios.c_cflag &= ~ADDRB;
+
sdio_uart_change_speed(port, &tty->termios, old_termios);
/* Handle transition to B0 status */
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index f97813a4e8d1..b687327bc7b1 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1099,7 +1099,8 @@ static void _hso_serial_set_termios(struct tty_struct *tty)
~(CSIZE /* no size */
| PARENB /* disable parity bit */
| CBAUD /* clear current baud rate */
- | CBAUDEX); /* clear current buad rate */
+ | CBAUDEX /* clear current baud rate */
+ | ADDRB); /* disable 9th (addr) bit */
tty->termios.c_cflag |= CS8; /* character size 8 bits */
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 5c83f71c1d0e..253d2997a1d3 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -1768,6 +1768,9 @@ tty3270_set_termios(struct tty_struct *tty, struct ktermios *old)
tp = tty->driver_data;
if (!tp)
return;
+
+ tty->termios.c_cflag &= ~ADDRB;
+
spin_lock_bh(&tp->view.lock);
if (L_ICANON(tty)) {
new = L_ECHO(tty) ? TF_INPUT: TF_INPUTN;
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index dc4ed0ff1ae2..83e73aefde0f 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -487,6 +487,8 @@ static void gb_tty_set_termios(struct tty_struct *tty,
struct ktermios *termios = &tty->termios;
u8 newctrl = gb_tty->ctrlout;
+ termios->c_cflag &= ~ADDRB;
+
newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
newline.format = termios->c_cflag & CSTOPB ?
GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 533d02b38e02..3ca97007bd6e 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1175,7 +1175,11 @@ static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
struct serial_state *info = tty->driver_data;
unsigned long flags;
- unsigned int cflag = tty->termios.c_cflag;
+ unsigned int cflag;
+
+ tty->termios.c_cflag &= ~ADDRB;
+
+ cflag = tty->termios.c_cflag;
change_speed(tty, info, old_termios);
diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c
index f3c72ab1476c..07cd88152d58 100644
--- a/drivers/tty/moxa.c
+++ b/drivers/tty/moxa.c
@@ -2050,6 +2050,7 @@ static int MoxaPortSetTermio(struct moxa_port *port, struct ktermios *termio,
ofsAddr = port->tableAddr;
+ termio->c_cflag &= ~ADDRB;
mode = termio->c_cflag & CSIZE;
if (mode == CS5)
mode = MX_CS5;
diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 836c9eca2946..220676363a07 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -577,6 +577,7 @@ static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_term
struct mxser_port *info = tty->driver_data;
unsigned cflag, cval;
+ tty->termios.c_cflag &= ~ADDRB;
cflag = tty->termios.c_cflag;
if (mxser_set_baud(tty, tty_get_baud_rate(tty))) {
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c6ac91033e38..de198c2acefe 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1493,6 +1493,8 @@ static void uart_set_termios(struct tty_struct *tty,
goto out;
}
+ tty->termios.c_cflag &= ~ADDRB;
+
uart_change_speed(tty, state, old_termios);
/* reload cflag from termios; port driver may have overridden flags */
cflag = tty->termios.c_cflag;
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index 25c558e65ece..ee767cea18ed 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -714,6 +714,8 @@ static void set_termios(struct tty_struct *tty, struct ktermios *old_termios)
DBGINFO(("%s set_termios\n", tty->driver->name));
+ tty->termios.c_cflag &= ~ADDRB;
+
change_params(info);
/* Handle transition to B0 status */
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 63181925ec1a..934037d78868 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;
}
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 9b9aea24d58c..fd246ec70da8 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1056,6 +1056,8 @@ static void acm_tty_set_termios(struct tty_struct *tty,
struct usb_cdc_line_coding newline;
int newctrl = acm->ctrlout;
+ termios->c_cflag &= ~ADDRB;
+
newline.dwDTERate = cpu_to_le32(tty_get_baud_rate(tty));
newline.bCharFormat = termios->c_cflag & CSTOPB ? 2 : 0;
newline.bParityType = termios->c_cflag & PARENB ?
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 24101bd7fcad..8d1d170eb7e6 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -525,10 +525,12 @@ static void serial_set_termios(struct tty_struct *tty, struct ktermios *old)
dev_dbg(&port->dev, "%s\n", __func__);
- if (port->serial->type->set_termios)
+ if (port->serial->type->set_termios) {
+ tty->termios.c_cflag &= ~ADDRB;
port->serial->type->set_termios(tty, port, old);
- else
+ } else {
tty_termios_copy_hw(&tty->termios, old);
+ }
}
static int serial_break(struct tty_struct *tty, int break_state)
diff --git a/include/uapi/asm-generic/termbits.h b/include/uapi/asm-generic/termbits.h
index 2fbaf9ae89dd..e06eaa9cf8be 100644
--- a/include/uapi/asm-generic/termbits.h
+++ b/include/uapi/asm-generic/termbits.h
@@ -158,6 +158,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index ebd78fdbd6e8..832e725f23ab 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -871,6 +871,8 @@ static void rfcomm_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
if (!dev || !dev->dlc || !dev->dlc->session)
return;
+ new->c_cflag &= ~ADDRB;
+
/* Handle turning off CRTSCTS */
if ((old->c_cflag & CRTSCTS) && !(new->c_cflag & CRTSCTS))
BT_DBG("Turning off CRTSCTS unsupported");
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 07/12] serial: termbits: ADDRB to indicate 9th bit addressing mode
@ 2022-04-11 8:33 ` Ilpo Järvinen
0 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, linux-api,
Ivan Kokshaysky, Matt Turner, linux-alpha, Thomas Bogendoerfer,
linux-mips, James E.J. Bottomley, Helge Deller, linux-parisc,
Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
linuxppc-dev
Add ADDRB to termbits to indicate 9th bit addressing mode.
This change is necessary for supporting devices with RS485
multipoint addressing [*]. A later patch in the patch series
adds support for Synopsys Designware UART capable for 9th bit
addressing mode. In this mode, 9th bit is used to indicate an
address (byte) within the communication line. The 9th bit
addressing mode is selected using ADDRB introduced by an earlier
patch.
[*] 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.
Cc: linux-api@vger.kernel.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
arch/alpha/include/uapi/asm/termbits.h | 1 +
arch/mips/include/uapi/asm/termbits.h | 1 +
arch/parisc/include/uapi/asm/termbits.h | 1 +
arch/powerpc/include/uapi/asm/termbits.h | 1 +
arch/sparc/include/uapi/asm/termbits.h | 1 +
drivers/char/pcmcia/synclink_cs.c | 2 ++
drivers/ipack/devices/ipoctal.c | 2 ++
drivers/mmc/core/sdio_uart.c | 2 ++
drivers/net/usb/hso.c | 3 ++-
drivers/s390/char/tty3270.c | 3 +++
drivers/staging/greybus/uart.c | 2 ++
drivers/tty/amiserial.c | 6 +++++-
drivers/tty/moxa.c | 1 +
drivers/tty/mxser.c | 1 +
drivers/tty/serial/serial_core.c | 2 ++
drivers/tty/synclink_gt.c | 2 ++
drivers/tty/tty_ioctl.c | 2 ++
drivers/usb/class/cdc-acm.c | 2 ++
drivers/usb/serial/usb-serial.c | 6 ++++--
include/uapi/asm-generic/termbits.h | 1 +
net/bluetooth/rfcomm/tty.c | 2 ++
21 files changed, 40 insertions(+), 4 deletions(-)
diff --git a/arch/alpha/include/uapi/asm/termbits.h b/arch/alpha/include/uapi/asm/termbits.h
index 4575ba34a0ea..0c123e715486 100644
--- a/arch/alpha/include/uapi/asm/termbits.h
+++ b/arch/alpha/include/uapi/asm/termbits.h
@@ -180,6 +180,7 @@ struct ktermios {
#define HUPCL 00040000
#define CLOCAL 00100000
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/mips/include/uapi/asm/termbits.h b/arch/mips/include/uapi/asm/termbits.h
index dfeffba729b7..4732d31b0e4e 100644
--- a/arch/mips/include/uapi/asm/termbits.h
+++ b/arch/mips/include/uapi/asm/termbits.h
@@ -182,6 +182,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/parisc/include/uapi/asm/termbits.h b/arch/parisc/include/uapi/asm/termbits.h
index 40e920f8d683..d6bbd10d92ba 100644
--- a/arch/parisc/include/uapi/asm/termbits.h
+++ b/arch/parisc/include/uapi/asm/termbits.h
@@ -159,6 +159,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/powerpc/include/uapi/asm/termbits.h b/arch/powerpc/include/uapi/asm/termbits.h
index ed18bc61f63d..c6a033732f39 100644
--- a/arch/powerpc/include/uapi/asm/termbits.h
+++ b/arch/powerpc/include/uapi/asm/termbits.h
@@ -171,6 +171,7 @@ struct ktermios {
#define HUPCL 00040000
#define CLOCAL 00100000
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/sparc/include/uapi/asm/termbits.h b/arch/sparc/include/uapi/asm/termbits.h
index ce5ad5d0f105..5eb1d547b5c4 100644
--- a/arch/sparc/include/uapi/asm/termbits.h
+++ b/arch/sparc/include/uapi/asm/termbits.h
@@ -201,6 +201,7 @@ struct ktermios {
#define B3500000 0x00001012
#define B4000000 0x00001013 */
#define CIBAUD 0x100f0000 /* input baud rate (not used) */
+#define ADDRB 0x20000000 /* address bit */
#define CMSPAR 0x40000000 /* mark or space (stick) parity */
#define CRTSCTS 0x80000000 /* flow control */
diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c
index 78baba55a8b5..d179b9b57a25 100644
--- a/drivers/char/pcmcia/synclink_cs.c
+++ b/drivers/char/pcmcia/synclink_cs.c
@@ -2287,6 +2287,8 @@ static void mgslpc_set_termios(struct tty_struct *tty, struct ktermios *old_term
== RELEVANT_IFLAG(old_termios->c_iflag)))
return;
+ tty->termios.c_cflag &= ~ADDRB;
+
mgslpc_change_params(info, tty);
/* Handle transition to B0 status */
diff --git a/drivers/ipack/devices/ipoctal.c b/drivers/ipack/devices/ipoctal.c
index 20d2b9ec1227..d66cc9683ebc 100644
--- a/drivers/ipack/devices/ipoctal.c
+++ b/drivers/ipack/devices/ipoctal.c
@@ -506,6 +506,8 @@ static void ipoctal_set_termios(struct tty_struct *tty,
struct ipoctal_channel *channel = tty->driver_data;
speed_t baud;
+ tty->termios.c_cflag &= ~ADDRB;
+
cflag = tty->termios.c_cflag;
/* Disable and reset everything before change the setup */
diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c
index 04c0823e0359..7432b01379ef 100644
--- a/drivers/mmc/core/sdio_uart.c
+++ b/drivers/mmc/core/sdio_uart.c
@@ -880,6 +880,8 @@ static void sdio_uart_set_termios(struct tty_struct *tty,
if (sdio_uart_claim_func(port) != 0)
return;
+ tty->termios.c_cflag &= ~ADDRB;
+
sdio_uart_change_speed(port, &tty->termios, old_termios);
/* Handle transition to B0 status */
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index f97813a4e8d1..b687327bc7b1 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1099,7 +1099,8 @@ static void _hso_serial_set_termios(struct tty_struct *tty)
~(CSIZE /* no size */
| PARENB /* disable parity bit */
| CBAUD /* clear current baud rate */
- | CBAUDEX); /* clear current buad rate */
+ | CBAUDEX /* clear current baud rate */
+ | ADDRB); /* disable 9th (addr) bit */
tty->termios.c_cflag |= CS8; /* character size 8 bits */
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 5c83f71c1d0e..253d2997a1d3 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -1768,6 +1768,9 @@ tty3270_set_termios(struct tty_struct *tty, struct ktermios *old)
tp = tty->driver_data;
if (!tp)
return;
+
+ tty->termios.c_cflag &= ~ADDRB;
+
spin_lock_bh(&tp->view.lock);
if (L_ICANON(tty)) {
new = L_ECHO(tty) ? TF_INPUT: TF_INPUTN;
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index dc4ed0ff1ae2..83e73aefde0f 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -487,6 +487,8 @@ static void gb_tty_set_termios(struct tty_struct *tty,
struct ktermios *termios = &tty->termios;
u8 newctrl = gb_tty->ctrlout;
+ termios->c_cflag &= ~ADDRB;
+
newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
newline.format = termios->c_cflag & CSTOPB ?
GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 533d02b38e02..3ca97007bd6e 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1175,7 +1175,11 @@ static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
struct serial_state *info = tty->driver_data;
unsigned long flags;
- unsigned int cflag = tty->termios.c_cflag;
+ unsigned int cflag;
+
+ tty->termios.c_cflag &= ~ADDRB;
+
+ cflag = tty->termios.c_cflag;
change_speed(tty, info, old_termios);
diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c
index f3c72ab1476c..07cd88152d58 100644
--- a/drivers/tty/moxa.c
+++ b/drivers/tty/moxa.c
@@ -2050,6 +2050,7 @@ static int MoxaPortSetTermio(struct moxa_port *port, struct ktermios *termio,
ofsAddr = port->tableAddr;
+ termio->c_cflag &= ~ADDRB;
mode = termio->c_cflag & CSIZE;
if (mode == CS5)
mode = MX_CS5;
diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 836c9eca2946..220676363a07 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -577,6 +577,7 @@ static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_term
struct mxser_port *info = tty->driver_data;
unsigned cflag, cval;
+ tty->termios.c_cflag &= ~ADDRB;
cflag = tty->termios.c_cflag;
if (mxser_set_baud(tty, tty_get_baud_rate(tty))) {
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c6ac91033e38..de198c2acefe 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1493,6 +1493,8 @@ static void uart_set_termios(struct tty_struct *tty,
goto out;
}
+ tty->termios.c_cflag &= ~ADDRB;
+
uart_change_speed(tty, state, old_termios);
/* reload cflag from termios; port driver may have overridden flags */
cflag = tty->termios.c_cflag;
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index 25c558e65ece..ee767cea18ed 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -714,6 +714,8 @@ static void set_termios(struct tty_struct *tty, struct ktermios *old_termios)
DBGINFO(("%s set_termios\n", tty->driver->name));
+ tty->termios.c_cflag &= ~ADDRB;
+
change_params(info);
/* Handle transition to B0 status */
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 63181925ec1a..934037d78868 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;
}
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 9b9aea24d58c..fd246ec70da8 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1056,6 +1056,8 @@ static void acm_tty_set_termios(struct tty_struct *tty,
struct usb_cdc_line_coding newline;
int newctrl = acm->ctrlout;
+ termios->c_cflag &= ~ADDRB;
+
newline.dwDTERate = cpu_to_le32(tty_get_baud_rate(tty));
newline.bCharFormat = termios->c_cflag & CSTOPB ? 2 : 0;
newline.bParityType = termios->c_cflag & PARENB ?
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 24101bd7fcad..8d1d170eb7e6 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -525,10 +525,12 @@ static void serial_set_termios(struct tty_struct *tty, struct ktermios *old)
dev_dbg(&port->dev, "%s\n", __func__);
- if (port->serial->type->set_termios)
+ if (port->serial->type->set_termios) {
+ tty->termios.c_cflag &= ~ADDRB;
port->serial->type->set_termios(tty, port, old);
- else
+ } else {
tty_termios_copy_hw(&tty->termios, old);
+ }
}
static int serial_break(struct tty_struct *tty, int break_state)
diff --git a/include/uapi/asm-generic/termbits.h b/include/uapi/asm-generic/termbits.h
index 2fbaf9ae89dd..e06eaa9cf8be 100644
--- a/include/uapi/asm-generic/termbits.h
+++ b/include/uapi/asm-generic/termbits.h
@@ -158,6 +158,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index ebd78fdbd6e8..832e725f23ab 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -871,6 +871,8 @@ static void rfcomm_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
if (!dev || !dev->dlc || !dev->dlc->session)
return;
+ new->c_cflag &= ~ADDRB;
+
/* Handle turning off CRTSCTS */
if ((old->c_cflag & CRTSCTS) && !(new->c_cflag & CRTSCTS))
BT_DBG("Turning off CRTSCTS unsupported");
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 07/12] serial: termbits: ADDRB to indicate 9th bit addressing mode
@ 2022-04-11 8:33 ` Ilpo Järvinen
0 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Heikki Krogerus, heiko, James E.J. Bottomley, Paul Mackerras,
sparclinux, linux-arch, Helge Deller, Uwe Kleine-König,
Ilpo Järvinen, Matt Turner, Arnd Bergmann, Johan Hovold,
Ivan Kokshaysky, Thomas Bogendoerfer, linux-parisc, linux-api,
linux-usb, linux-mips, giulio.benetti, linux-alpha, linuxppc-dev,
David S. Miller
Add ADDRB to termbits to indicate 9th bit addressing mode.
This change is necessary for supporting devices with RS485
multipoint addressing [*]. A later patch in the patch series
adds support for Synopsys Designware UART capable for 9th bit
addressing mode. In this mode, 9th bit is used to indicate an
address (byte) within the communication line. The 9th bit
addressing mode is selected using ADDRB introduced by an earlier
patch.
[*] 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.
Cc: linux-api@vger.kernel.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
arch/alpha/include/uapi/asm/termbits.h | 1 +
arch/mips/include/uapi/asm/termbits.h | 1 +
arch/parisc/include/uapi/asm/termbits.h | 1 +
arch/powerpc/include/uapi/asm/termbits.h | 1 +
arch/sparc/include/uapi/asm/termbits.h | 1 +
drivers/char/pcmcia/synclink_cs.c | 2 ++
drivers/ipack/devices/ipoctal.c | 2 ++
drivers/mmc/core/sdio_uart.c | 2 ++
drivers/net/usb/hso.c | 3 ++-
drivers/s390/char/tty3270.c | 3 +++
drivers/staging/greybus/uart.c | 2 ++
drivers/tty/amiserial.c | 6 +++++-
drivers/tty/moxa.c | 1 +
drivers/tty/mxser.c | 1 +
drivers/tty/serial/serial_core.c | 2 ++
drivers/tty/synclink_gt.c | 2 ++
drivers/tty/tty_ioctl.c | 2 ++
drivers/usb/class/cdc-acm.c | 2 ++
drivers/usb/serial/usb-serial.c | 6 ++++--
include/uapi/asm-generic/termbits.h | 1 +
net/bluetooth/rfcomm/tty.c | 2 ++
21 files changed, 40 insertions(+), 4 deletions(-)
diff --git a/arch/alpha/include/uapi/asm/termbits.h b/arch/alpha/include/uapi/asm/termbits.h
index 4575ba34a0ea..0c123e715486 100644
--- a/arch/alpha/include/uapi/asm/termbits.h
+++ b/arch/alpha/include/uapi/asm/termbits.h
@@ -180,6 +180,7 @@ struct ktermios {
#define HUPCL 00040000
#define CLOCAL 00100000
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/mips/include/uapi/asm/termbits.h b/arch/mips/include/uapi/asm/termbits.h
index dfeffba729b7..4732d31b0e4e 100644
--- a/arch/mips/include/uapi/asm/termbits.h
+++ b/arch/mips/include/uapi/asm/termbits.h
@@ -182,6 +182,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/parisc/include/uapi/asm/termbits.h b/arch/parisc/include/uapi/asm/termbits.h
index 40e920f8d683..d6bbd10d92ba 100644
--- a/arch/parisc/include/uapi/asm/termbits.h
+++ b/arch/parisc/include/uapi/asm/termbits.h
@@ -159,6 +159,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/powerpc/include/uapi/asm/termbits.h b/arch/powerpc/include/uapi/asm/termbits.h
index ed18bc61f63d..c6a033732f39 100644
--- a/arch/powerpc/include/uapi/asm/termbits.h
+++ b/arch/powerpc/include/uapi/asm/termbits.h
@@ -171,6 +171,7 @@ struct ktermios {
#define HUPCL 00040000
#define CLOCAL 00100000
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/arch/sparc/include/uapi/asm/termbits.h b/arch/sparc/include/uapi/asm/termbits.h
index ce5ad5d0f105..5eb1d547b5c4 100644
--- a/arch/sparc/include/uapi/asm/termbits.h
+++ b/arch/sparc/include/uapi/asm/termbits.h
@@ -201,6 +201,7 @@ struct ktermios {
#define B3500000 0x00001012
#define B4000000 0x00001013 */
#define CIBAUD 0x100f0000 /* input baud rate (not used) */
+#define ADDRB 0x20000000 /* address bit */
#define CMSPAR 0x40000000 /* mark or space (stick) parity */
#define CRTSCTS 0x80000000 /* flow control */
diff --git a/drivers/char/pcmcia/synclink_cs.c b/drivers/char/pcmcia/synclink_cs.c
index 78baba55a8b5..d179b9b57a25 100644
--- a/drivers/char/pcmcia/synclink_cs.c
+++ b/drivers/char/pcmcia/synclink_cs.c
@@ -2287,6 +2287,8 @@ static void mgslpc_set_termios(struct tty_struct *tty, struct ktermios *old_term
== RELEVANT_IFLAG(old_termios->c_iflag)))
return;
+ tty->termios.c_cflag &= ~ADDRB;
+
mgslpc_change_params(info, tty);
/* Handle transition to B0 status */
diff --git a/drivers/ipack/devices/ipoctal.c b/drivers/ipack/devices/ipoctal.c
index 20d2b9ec1227..d66cc9683ebc 100644
--- a/drivers/ipack/devices/ipoctal.c
+++ b/drivers/ipack/devices/ipoctal.c
@@ -506,6 +506,8 @@ static void ipoctal_set_termios(struct tty_struct *tty,
struct ipoctal_channel *channel = tty->driver_data;
speed_t baud;
+ tty->termios.c_cflag &= ~ADDRB;
+
cflag = tty->termios.c_cflag;
/* Disable and reset everything before change the setup */
diff --git a/drivers/mmc/core/sdio_uart.c b/drivers/mmc/core/sdio_uart.c
index 04c0823e0359..7432b01379ef 100644
--- a/drivers/mmc/core/sdio_uart.c
+++ b/drivers/mmc/core/sdio_uart.c
@@ -880,6 +880,8 @@ static void sdio_uart_set_termios(struct tty_struct *tty,
if (sdio_uart_claim_func(port) != 0)
return;
+ tty->termios.c_cflag &= ~ADDRB;
+
sdio_uart_change_speed(port, &tty->termios, old_termios);
/* Handle transition to B0 status */
diff --git a/drivers/net/usb/hso.c b/drivers/net/usb/hso.c
index f97813a4e8d1..b687327bc7b1 100644
--- a/drivers/net/usb/hso.c
+++ b/drivers/net/usb/hso.c
@@ -1099,7 +1099,8 @@ static void _hso_serial_set_termios(struct tty_struct *tty)
~(CSIZE /* no size */
| PARENB /* disable parity bit */
| CBAUD /* clear current baud rate */
- | CBAUDEX); /* clear current buad rate */
+ | CBAUDEX /* clear current baud rate */
+ | ADDRB); /* disable 9th (addr) bit */
tty->termios.c_cflag |= CS8; /* character size 8 bits */
diff --git a/drivers/s390/char/tty3270.c b/drivers/s390/char/tty3270.c
index 5c83f71c1d0e..253d2997a1d3 100644
--- a/drivers/s390/char/tty3270.c
+++ b/drivers/s390/char/tty3270.c
@@ -1768,6 +1768,9 @@ tty3270_set_termios(struct tty_struct *tty, struct ktermios *old)
tp = tty->driver_data;
if (!tp)
return;
+
+ tty->termios.c_cflag &= ~ADDRB;
+
spin_lock_bh(&tp->view.lock);
if (L_ICANON(tty)) {
new = L_ECHO(tty) ? TF_INPUT: TF_INPUTN;
diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
index dc4ed0ff1ae2..83e73aefde0f 100644
--- a/drivers/staging/greybus/uart.c
+++ b/drivers/staging/greybus/uart.c
@@ -487,6 +487,8 @@ static void gb_tty_set_termios(struct tty_struct *tty,
struct ktermios *termios = &tty->termios;
u8 newctrl = gb_tty->ctrlout;
+ termios->c_cflag &= ~ADDRB;
+
newline.rate = cpu_to_le32(tty_get_baud_rate(tty));
newline.format = termios->c_cflag & CSTOPB ?
GB_SERIAL_2_STOP_BITS : GB_SERIAL_1_STOP_BITS;
diff --git a/drivers/tty/amiserial.c b/drivers/tty/amiserial.c
index 533d02b38e02..3ca97007bd6e 100644
--- a/drivers/tty/amiserial.c
+++ b/drivers/tty/amiserial.c
@@ -1175,7 +1175,11 @@ static void rs_set_termios(struct tty_struct *tty, struct ktermios *old_termios)
{
struct serial_state *info = tty->driver_data;
unsigned long flags;
- unsigned int cflag = tty->termios.c_cflag;
+ unsigned int cflag;
+
+ tty->termios.c_cflag &= ~ADDRB;
+
+ cflag = tty->termios.c_cflag;
change_speed(tty, info, old_termios);
diff --git a/drivers/tty/moxa.c b/drivers/tty/moxa.c
index f3c72ab1476c..07cd88152d58 100644
--- a/drivers/tty/moxa.c
+++ b/drivers/tty/moxa.c
@@ -2050,6 +2050,7 @@ static int MoxaPortSetTermio(struct moxa_port *port, struct ktermios *termio,
ofsAddr = port->tableAddr;
+ termio->c_cflag &= ~ADDRB;
mode = termio->c_cflag & CSIZE;
if (mode == CS5)
mode = MX_CS5;
diff --git a/drivers/tty/mxser.c b/drivers/tty/mxser.c
index 836c9eca2946..220676363a07 100644
--- a/drivers/tty/mxser.c
+++ b/drivers/tty/mxser.c
@@ -577,6 +577,7 @@ static void mxser_change_speed(struct tty_struct *tty, struct ktermios *old_term
struct mxser_port *info = tty->driver_data;
unsigned cflag, cval;
+ tty->termios.c_cflag &= ~ADDRB;
cflag = tty->termios.c_cflag;
if (mxser_set_baud(tty, tty_get_baud_rate(tty))) {
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index c6ac91033e38..de198c2acefe 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1493,6 +1493,8 @@ static void uart_set_termios(struct tty_struct *tty,
goto out;
}
+ tty->termios.c_cflag &= ~ADDRB;
+
uart_change_speed(tty, state, old_termios);
/* reload cflag from termios; port driver may have overridden flags */
cflag = tty->termios.c_cflag;
diff --git a/drivers/tty/synclink_gt.c b/drivers/tty/synclink_gt.c
index 25c558e65ece..ee767cea18ed 100644
--- a/drivers/tty/synclink_gt.c
+++ b/drivers/tty/synclink_gt.c
@@ -714,6 +714,8 @@ static void set_termios(struct tty_struct *tty, struct ktermios *old_termios)
DBGINFO(("%s set_termios\n", tty->driver->name));
+ tty->termios.c_cflag &= ~ADDRB;
+
change_params(info);
/* Handle transition to B0 status */
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
index 63181925ec1a..934037d78868 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;
}
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 9b9aea24d58c..fd246ec70da8 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1056,6 +1056,8 @@ static void acm_tty_set_termios(struct tty_struct *tty,
struct usb_cdc_line_coding newline;
int newctrl = acm->ctrlout;
+ termios->c_cflag &= ~ADDRB;
+
newline.dwDTERate = cpu_to_le32(tty_get_baud_rate(tty));
newline.bCharFormat = termios->c_cflag & CSTOPB ? 2 : 0;
newline.bParityType = termios->c_cflag & PARENB ?
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 24101bd7fcad..8d1d170eb7e6 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -525,10 +525,12 @@ static void serial_set_termios(struct tty_struct *tty, struct ktermios *old)
dev_dbg(&port->dev, "%s\n", __func__);
- if (port->serial->type->set_termios)
+ if (port->serial->type->set_termios) {
+ tty->termios.c_cflag &= ~ADDRB;
port->serial->type->set_termios(tty, port, old);
- else
+ } else {
tty_termios_copy_hw(&tty->termios, old);
+ }
}
static int serial_break(struct tty_struct *tty, int break_state)
diff --git a/include/uapi/asm-generic/termbits.h b/include/uapi/asm-generic/termbits.h
index 2fbaf9ae89dd..e06eaa9cf8be 100644
--- a/include/uapi/asm-generic/termbits.h
+++ b/include/uapi/asm-generic/termbits.h
@@ -158,6 +158,7 @@ struct ktermios {
#define B3500000 0010016
#define B4000000 0010017
#define CIBAUD 002003600000 /* input baud rate */
+#define ADDRB 004000000000 /* address bit */
#define CMSPAR 010000000000 /* mark or space (stick) parity */
#define CRTSCTS 020000000000 /* flow control */
diff --git a/net/bluetooth/rfcomm/tty.c b/net/bluetooth/rfcomm/tty.c
index ebd78fdbd6e8..832e725f23ab 100644
--- a/net/bluetooth/rfcomm/tty.c
+++ b/net/bluetooth/rfcomm/tty.c
@@ -871,6 +871,8 @@ static void rfcomm_tty_set_termios(struct tty_struct *tty, struct ktermios *old)
if (!dev || !dev->dlc || !dev->dlc->session)
return;
+ new->c_cflag &= ~ADDRB;
+
/* Handle turning off CRTSCTS */
if ((old->c_cflag & CRTSCTS) && !(new->c_cflag & CRTSCTS))
BT_DBG("Turning off CRTSCTS unsupported");
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread
* [PATCH v3 08/12] serial: General support for multipoint addresses
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 01/12] serial: Store character timing information to uart_port Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 03/12] serial: 8250_dwlib: RS485 HW half & full duplex support Ilpo Järvinen
` (10 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, linux-api,
Ivan Kokshaysky, Matt Turner, linux-alpha, Thomas Bogendoerfer,
linux-mips, James E.J. Bottomley, Helge Deller, linux-parisc,
Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
linuxppc-dev, Yoshinori Sato, Rich Felker, linux-sh,
David S. Miller, sparclinux, Chris Zankel, Max Filippov,
linux-xtensa, Arnd Bergmann, linux-arch, linux-doc
Add generic support for serial multipoint addressing. Two new
ioctls are added. TIOCSADDR is used to indicate the
destination/receive address. TIOCGADDR returns the current
address in use. The driver should implement set_addr and get_addr
to support addressing mode.
Adjust ADDRB clearing to happen only if driver does not provide
set_addr (=the driver doesn't support address mode).
This change is necessary for supporting devices with RS485
multipoint addressing [*]. A following patch in the patch series
adds support for Synopsys Designware UART capable for 9th bit
addressing mode. In this mode, 9th bit is used to indicate an
address (byte) within the communication line. The 9th bit
addressing mode is selected using ADDRB introduced by the
previous patch.
Transmit addresses / receiver filter are specified by setting
the flags SER_ADDR_DEST and/or SER_ADDR_RECV. When the user
supplies the transmit address, in the 9bit addressing mode it is
sent out immediately with the 9th bit set to 1. After that, the
subsequent normal data bytes are sent with 9th bit as 0 and they
are intended to the device with the given address. It is up to
receiver to enforce the filter using SER_ADDR_RECV. When userspace
has supplied the receive address, the driver is expected to handle
the matching of the address and only data with that address is
forwarded to the user. Both SER_ADDR_DEST and SER_ADDR_RECV can
be given at the same time in a single call if the addresses are
the same.
The user can clear the receive filter with SER_ADDR_RECV_CLEAR.
[*] 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.
Cc: linux-api@vger.kernel.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-xtensa@linux-xtensa.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
.../driver-api/serial/serial-rs485.rst | 23 ++++++-
arch/alpha/include/uapi/asm/ioctls.h | 3 +
arch/mips/include/uapi/asm/ioctls.h | 3 +
arch/parisc/include/uapi/asm/ioctls.h | 3 +
arch/powerpc/include/uapi/asm/ioctls.h | 3 +
arch/sh/include/uapi/asm/ioctls.h | 3 +
arch/sparc/include/uapi/asm/ioctls.h | 3 +
arch/xtensa/include/uapi/asm/ioctls.h | 3 +
drivers/tty/serial/8250/8250_core.c | 2 +
drivers/tty/serial/serial_core.c | 62 ++++++++++++++++++-
drivers/tty/tty_io.c | 2 +
include/linux/serial_core.h | 6 ++
include/uapi/asm-generic/ioctls.h | 3 +
include/uapi/linux/serial.h | 8 +++
14 files changed, 125 insertions(+), 2 deletions(-)
diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index 6bc824f948f9..2f45f007fa5b 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -95,7 +95,28 @@ RS485 Serial Communications
/* Error handling. See errno. */
}
-5. References
+5. Multipoint Addressing
+========================
+
+ The Linux kernel provides serial_addr structure to handle addressing within
+ multipoint serial communications line such as RS485. 9th bit addressiong mode
+ is enabled by adding ADDRB flag in termios c_cflag.
+
+ Serial core calls device specific set/get_addr in response to TIOCSADDR and
+ TIOCGADDR ioctls with a pointer to serial_addr. Destination and receive
+ address can be specified using serial_addr flags field. Receive address may
+ also be cleared using flags. Once an address is set, the communication
+ can occur only with the particular device and other peers are filtered out.
+ It is left up to the receiver side to enforce the filtering.
+
+ Address flags:
+ - SER_ADDR_RECV: Receive (filter) address.
+ - SER_ADDR_RECV_CLEAR: Clear receive filter (only for TIOCSADDR).
+ - SER_ADDR_DEST: Destination address.
+
+ Note: not all devices supporting RS485 support multipoint addressing.
+
+6. References
=============
[1] include/uapi/linux/serial.h
diff --git a/arch/alpha/include/uapi/asm/ioctls.h b/arch/alpha/include/uapi/asm/ioctls.h
index 971311605288..500cab3e1d6b 100644
--- a/arch/alpha/include/uapi/asm/ioctls.h
+++ b/arch/alpha/include/uapi/asm/ioctls.h
@@ -125,4 +125,7 @@
#define TIOCMIWAIT 0x545C /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _ASM_ALPHA_IOCTLS_H */
diff --git a/arch/mips/include/uapi/asm/ioctls.h b/arch/mips/include/uapi/asm/ioctls.h
index 16aa8a766aec..3859dc46857e 100644
--- a/arch/mips/include/uapi/asm/ioctls.h
+++ b/arch/mips/include/uapi/asm/ioctls.h
@@ -96,6 +96,9 @@
#define TIOCGISO7816 _IOR('T', 0x42, struct serial_iso7816)
#define TIOCSISO7816 _IOWR('T', 0x43, struct serial_iso7816)
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* I hope the range from 0x5480 on is free ... */
#define TIOCSCTTY 0x5480 /* become controlling tty */
#define TIOCGSOFTCAR 0x5481
diff --git a/arch/parisc/include/uapi/asm/ioctls.h b/arch/parisc/include/uapi/asm/ioctls.h
index 82d1148c6379..62337743db64 100644
--- a/arch/parisc/include/uapi/asm/ioctls.h
+++ b/arch/parisc/include/uapi/asm/ioctls.h
@@ -86,6 +86,9 @@
#define TIOCSTOP 0x5462
#define TIOCSLTC 0x5462
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Used for packet mode */
#define TIOCPKT_DATA 0
#define TIOCPKT_FLUSHREAD 1
diff --git a/arch/powerpc/include/uapi/asm/ioctls.h b/arch/powerpc/include/uapi/asm/ioctls.h
index 2c145da3b774..84fd69ac366a 100644
--- a/arch/powerpc/include/uapi/asm/ioctls.h
+++ b/arch/powerpc/include/uapi/asm/ioctls.h
@@ -120,4 +120,7 @@
#define TIOCMIWAIT 0x545C /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _ASM_POWERPC_IOCTLS_H */
diff --git a/arch/sh/include/uapi/asm/ioctls.h b/arch/sh/include/uapi/asm/ioctls.h
index 11866d4f60e1..f82966b7dba2 100644
--- a/arch/sh/include/uapi/asm/ioctls.h
+++ b/arch/sh/include/uapi/asm/ioctls.h
@@ -113,4 +113,7 @@
#define TIOCMIWAIT _IO('T', 92) /* 0x545C */ /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* __ASM_SH_IOCTLS_H */
diff --git a/arch/sparc/include/uapi/asm/ioctls.h b/arch/sparc/include/uapi/asm/ioctls.h
index 7fd2f5873c9e..e44624c67c79 100644
--- a/arch/sparc/include/uapi/asm/ioctls.h
+++ b/arch/sparc/include/uapi/asm/ioctls.h
@@ -125,6 +125,9 @@
#define TIOCMIWAIT 0x545C /* Wait for change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* Read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Kernel definitions */
/* Used for packet mode */
diff --git a/arch/xtensa/include/uapi/asm/ioctls.h b/arch/xtensa/include/uapi/asm/ioctls.h
index 6d4a87296c95..759ca9377f2a 100644
--- a/arch/xtensa/include/uapi/asm/ioctls.h
+++ b/arch/xtensa/include/uapi/asm/ioctls.h
@@ -127,4 +127,7 @@
#define TIOCMIWAIT _IO('T', 92) /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _XTENSA_IOCTLS_H */
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 01d30f6ed8fb..f67bc3b76f65 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1008,6 +1008,8 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
uart->port.rs485 = up->port.rs485;
uart->rs485_start_tx = up->rs485_start_tx;
uart->rs485_stop_tx = up->rs485_stop_tx;
+ uart->port.set_addr = up->port.set_addr;
+ uart->port.get_addr = up->port.get_addr;
uart->dma = up->dma;
/* Take tx_loadsz from fifosize if it wasn't set separately */
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index de198c2acefe..2cd129c78ef6 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1350,6 +1350,56 @@ static int uart_set_iso7816_config(struct uart_port *port,
return 0;
}
+static int uart_set_addr(struct uart_port *port,
+ struct serial_addr __user *serial_addr_user)
+{
+ struct serial_addr addr;
+ unsigned long flags;
+ int ret;
+
+ if (!port->set_addr)
+ return -ENOTTY;
+
+ if (copy_from_user(&addr, serial_addr_user, sizeof(*serial_addr_user)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->set_addr(port, &addr);
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(serial_addr_user, &addr, sizeof(addr)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int uart_get_addr(struct uart_port *port,
+ struct serial_addr __user *serial_addr_user)
+{
+ struct serial_addr addr;
+ unsigned long flags;
+ int ret;
+
+ if (!port->get_addr)
+ return -ENOTTY;
+
+ if (copy_from_user(&addr, serial_addr_user, sizeof(*serial_addr_user)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->get_addr(port, &addr);
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(serial_addr_user, &addr, sizeof(addr)))
+ return -EFAULT;
+
+ return 0;
+}
+
/*
* Called via sys_ioctl. We can use spin_lock_irq() here.
*/
@@ -1427,6 +1477,15 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
case TIOCGISO7816:
ret = uart_get_iso7816_config(state->uart_port, uarg);
break;
+
+ case TIOCSADDR:
+ ret = uart_set_addr(uport, uarg);
+ break;
+
+ case TIOCGADDR:
+ ret = uart_get_addr(uport, uarg);
+ break;
+
default:
if (uport->ops->ioctl)
ret = uport->ops->ioctl(uport, cmd, arg);
@@ -1493,7 +1552,8 @@ static void uart_set_termios(struct tty_struct *tty,
goto out;
}
- tty->termios.c_cflag &= ~ADDRB;
+ if (!uport->set_addr)
+ tty->termios.c_cflag &= ~ADDRB;
uart_change_speed(tty, state, old_termios);
/* reload cflag from termios; port driver may have overridden flags */
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 7e8b3bd59c7b..93d8609e88aa 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2885,6 +2885,8 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
case TIOCSERGETLSR:
case TIOCGRS485:
case TIOCSRS485:
+ case TIOCSADDR:
+ case TIOCGADDR:
#ifdef TIOCGETP
case TIOCGETP:
case TIOCSETP:
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 504d365e2803..a2efd3fe2635 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -135,6 +135,12 @@ struct uart_port {
struct serial_rs485 *rs485);
int (*iso7816_config)(struct uart_port *,
struct serial_iso7816 *iso7816);
+
+ int (*set_addr)(struct uart_port *p,
+ struct serial_addr *addr);
+ int (*get_addr)(struct uart_port *p,
+ struct serial_addr *addr);
+
unsigned int irq; /* irq number */
unsigned long irqflags; /* irq flags */
unsigned int uartclk; /* base uart clock */
diff --git a/include/uapi/asm-generic/ioctls.h b/include/uapi/asm-generic/ioctls.h
index cdc9f4ca8c27..689743366091 100644
--- a/include/uapi/asm-generic/ioctls.h
+++ b/include/uapi/asm-generic/ioctls.h
@@ -106,6 +106,9 @@
# define FIOQSIZE 0x5460
#endif
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Used for packet mode */
#define TIOCPKT_DATA 0
#define TIOCPKT_FLUSHREAD 1
diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
index fa6b16e5fdd8..8cb785ea7087 100644
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -149,4 +149,12 @@ struct serial_iso7816 {
__u32 reserved[5];
};
+struct serial_addr {
+ __u32 flags;
+#define SER_ADDR_RECV (1 << 0)
+#define SER_ADDR_RECV_CLEAR (1 << 1)
+#define SER_ADDR_DEST (1 << 2)
+ __u32 addr;
+};
+
#endif /* _UAPI_LINUX_SERIAL_H */
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 08/12] serial: General support for multipoint addresses
@ 2022-04-11 8:33 ` Ilpo Järvinen
0 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, linux-api,
Ivan Kokshaysky, Matt Turner, linux-alpha, Thomas Bogendoerfer,
linux-mips, James E.J. Bottomley, Helge Deller, linux-parisc,
Michael Ellerman, Benjamin Herrenschmidt, Paul Mackerras,
linuxppc-dev
Add generic support for serial multipoint addressing. Two new
ioctls are added. TIOCSADDR is used to indicate the
destination/receive address. TIOCGADDR returns the current
address in use. The driver should implement set_addr and get_addr
to support addressing mode.
Adjust ADDRB clearing to happen only if driver does not provide
set_addr (=the driver doesn't support address mode).
This change is necessary for supporting devices with RS485
multipoint addressing [*]. A following patch in the patch series
adds support for Synopsys Designware UART capable for 9th bit
addressing mode. In this mode, 9th bit is used to indicate an
address (byte) within the communication line. The 9th bit
addressing mode is selected using ADDRB introduced by the
previous patch.
Transmit addresses / receiver filter are specified by setting
the flags SER_ADDR_DEST and/or SER_ADDR_RECV. When the user
supplies the transmit address, in the 9bit addressing mode it is
sent out immediately with the 9th bit set to 1. After that, the
subsequent normal data bytes are sent with 9th bit as 0 and they
are intended to the device with the given address. It is up to
receiver to enforce the filter using SER_ADDR_RECV. When userspace
has supplied the receive address, the driver is expected to handle
the matching of the address and only data with that address is
forwarded to the user. Both SER_ADDR_DEST and SER_ADDR_RECV can
be given at the same time in a single call if the addresses are
the same.
The user can clear the receive filter with SER_ADDR_RECV_CLEAR.
[*] 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.
Cc: linux-api@vger.kernel.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-xtensa@linux-xtensa.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
.../driver-api/serial/serial-rs485.rst | 23 ++++++-
arch/alpha/include/uapi/asm/ioctls.h | 3 +
arch/mips/include/uapi/asm/ioctls.h | 3 +
arch/parisc/include/uapi/asm/ioctls.h | 3 +
arch/powerpc/include/uapi/asm/ioctls.h | 3 +
arch/sh/include/uapi/asm/ioctls.h | 3 +
arch/sparc/include/uapi/asm/ioctls.h | 3 +
arch/xtensa/include/uapi/asm/ioctls.h | 3 +
drivers/tty/serial/8250/8250_core.c | 2 +
drivers/tty/serial/serial_core.c | 62 ++++++++++++++++++-
drivers/tty/tty_io.c | 2 +
include/linux/serial_core.h | 6 ++
include/uapi/asm-generic/ioctls.h | 3 +
include/uapi/linux/serial.h | 8 +++
14 files changed, 125 insertions(+), 2 deletions(-)
diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index 6bc824f948f9..2f45f007fa5b 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -95,7 +95,28 @@ RS485 Serial Communications
/* Error handling. See errno. */
}
-5. References
+5. Multipoint Addressing
+========================
+
+ The Linux kernel provides serial_addr structure to handle addressing within
+ multipoint serial communications line such as RS485. 9th bit addressiong mode
+ is enabled by adding ADDRB flag in termios c_cflag.
+
+ Serial core calls device specific set/get_addr in response to TIOCSADDR and
+ TIOCGADDR ioctls with a pointer to serial_addr. Destination and receive
+ address can be specified using serial_addr flags field. Receive address may
+ also be cleared using flags. Once an address is set, the communication
+ can occur only with the particular device and other peers are filtered out.
+ It is left up to the receiver side to enforce the filtering.
+
+ Address flags:
+ - SER_ADDR_RECV: Receive (filter) address.
+ - SER_ADDR_RECV_CLEAR: Clear receive filter (only for TIOCSADDR).
+ - SER_ADDR_DEST: Destination address.
+
+ Note: not all devices supporting RS485 support multipoint addressing.
+
+6. References
=============
[1] include/uapi/linux/serial.h
diff --git a/arch/alpha/include/uapi/asm/ioctls.h b/arch/alpha/include/uapi/asm/ioctls.h
index 971311605288..500cab3e1d6b 100644
--- a/arch/alpha/include/uapi/asm/ioctls.h
+++ b/arch/alpha/include/uapi/asm/ioctls.h
@@ -125,4 +125,7 @@
#define TIOCMIWAIT 0x545C /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _ASM_ALPHA_IOCTLS_H */
diff --git a/arch/mips/include/uapi/asm/ioctls.h b/arch/mips/include/uapi/asm/ioctls.h
index 16aa8a766aec..3859dc46857e 100644
--- a/arch/mips/include/uapi/asm/ioctls.h
+++ b/arch/mips/include/uapi/asm/ioctls.h
@@ -96,6 +96,9 @@
#define TIOCGISO7816 _IOR('T', 0x42, struct serial_iso7816)
#define TIOCSISO7816 _IOWR('T', 0x43, struct serial_iso7816)
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* I hope the range from 0x5480 on is free ... */
#define TIOCSCTTY 0x5480 /* become controlling tty */
#define TIOCGSOFTCAR 0x5481
diff --git a/arch/parisc/include/uapi/asm/ioctls.h b/arch/parisc/include/uapi/asm/ioctls.h
index 82d1148c6379..62337743db64 100644
--- a/arch/parisc/include/uapi/asm/ioctls.h
+++ b/arch/parisc/include/uapi/asm/ioctls.h
@@ -86,6 +86,9 @@
#define TIOCSTOP 0x5462
#define TIOCSLTC 0x5462
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Used for packet mode */
#define TIOCPKT_DATA 0
#define TIOCPKT_FLUSHREAD 1
diff --git a/arch/powerpc/include/uapi/asm/ioctls.h b/arch/powerpc/include/uapi/asm/ioctls.h
index 2c145da3b774..84fd69ac366a 100644
--- a/arch/powerpc/include/uapi/asm/ioctls.h
+++ b/arch/powerpc/include/uapi/asm/ioctls.h
@@ -120,4 +120,7 @@
#define TIOCMIWAIT 0x545C /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _ASM_POWERPC_IOCTLS_H */
diff --git a/arch/sh/include/uapi/asm/ioctls.h b/arch/sh/include/uapi/asm/ioctls.h
index 11866d4f60e1..f82966b7dba2 100644
--- a/arch/sh/include/uapi/asm/ioctls.h
+++ b/arch/sh/include/uapi/asm/ioctls.h
@@ -113,4 +113,7 @@
#define TIOCMIWAIT _IO('T', 92) /* 0x545C */ /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* __ASM_SH_IOCTLS_H */
diff --git a/arch/sparc/include/uapi/asm/ioctls.h b/arch/sparc/include/uapi/asm/ioctls.h
index 7fd2f5873c9e..e44624c67c79 100644
--- a/arch/sparc/include/uapi/asm/ioctls.h
+++ b/arch/sparc/include/uapi/asm/ioctls.h
@@ -125,6 +125,9 @@
#define TIOCMIWAIT 0x545C /* Wait for change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* Read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Kernel definitions */
/* Used for packet mode */
diff --git a/arch/xtensa/include/uapi/asm/ioctls.h b/arch/xtensa/include/uapi/asm/ioctls.h
index 6d4a87296c95..759ca9377f2a 100644
--- a/arch/xtensa/include/uapi/asm/ioctls.h
+++ b/arch/xtensa/include/uapi/asm/ioctls.h
@@ -127,4 +127,7 @@
#define TIOCMIWAIT _IO('T', 92) /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _XTENSA_IOCTLS_H */
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 01d30f6ed8fb..f67bc3b76f65 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1008,6 +1008,8 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
uart->port.rs485 = up->port.rs485;
uart->rs485_start_tx = up->rs485_start_tx;
uart->rs485_stop_tx = up->rs485_stop_tx;
+ uart->port.set_addr = up->port.set_addr;
+ uart->port.get_addr = up->port.get_addr;
uart->dma = up->dma;
/* Take tx_loadsz from fifosize if it wasn't set separately */
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index de198c2acefe..2cd129c78ef6 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1350,6 +1350,56 @@ static int uart_set_iso7816_config(struct uart_port *port,
return 0;
}
+static int uart_set_addr(struct uart_port *port,
+ struct serial_addr __user *serial_addr_user)
+{
+ struct serial_addr addr;
+ unsigned long flags;
+ int ret;
+
+ if (!port->set_addr)
+ return -ENOTTY;
+
+ if (copy_from_user(&addr, serial_addr_user, sizeof(*serial_addr_user)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->set_addr(port, &addr);
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(serial_addr_user, &addr, sizeof(addr)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int uart_get_addr(struct uart_port *port,
+ struct serial_addr __user *serial_addr_user)
+{
+ struct serial_addr addr;
+ unsigned long flags;
+ int ret;
+
+ if (!port->get_addr)
+ return -ENOTTY;
+
+ if (copy_from_user(&addr, serial_addr_user, sizeof(*serial_addr_user)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->get_addr(port, &addr);
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(serial_addr_user, &addr, sizeof(addr)))
+ return -EFAULT;
+
+ return 0;
+}
+
/*
* Called via sys_ioctl. We can use spin_lock_irq() here.
*/
@@ -1427,6 +1477,15 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
case TIOCGISO7816:
ret = uart_get_iso7816_config(state->uart_port, uarg);
break;
+
+ case TIOCSADDR:
+ ret = uart_set_addr(uport, uarg);
+ break;
+
+ case TIOCGADDR:
+ ret = uart_get_addr(uport, uarg);
+ break;
+
default:
if (uport->ops->ioctl)
ret = uport->ops->ioctl(uport, cmd, arg);
@@ -1493,7 +1552,8 @@ static void uart_set_termios(struct tty_struct *tty,
goto out;
}
- tty->termios.c_cflag &= ~ADDRB;
+ if (!uport->set_addr)
+ tty->termios.c_cflag &= ~ADDRB;
uart_change_speed(tty, state, old_termios);
/* reload cflag from termios; port driver may have overridden flags */
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 7e8b3bd59c7b..93d8609e88aa 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2885,6 +2885,8 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
case TIOCSERGETLSR:
case TIOCGRS485:
case TIOCSRS485:
+ case TIOCSADDR:
+ case TIOCGADDR:
#ifdef TIOCGETP
case TIOCGETP:
case TIOCSETP:
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 504d365e2803..a2efd3fe2635 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -135,6 +135,12 @@ struct uart_port {
struct serial_rs485 *rs485);
int (*iso7816_config)(struct uart_port *,
struct serial_iso7816 *iso7816);
+
+ int (*set_addr)(struct uart_port *p,
+ struct serial_addr *addr);
+ int (*get_addr)(struct uart_port *p,
+ struct serial_addr *addr);
+
unsigned int irq; /* irq number */
unsigned long irqflags; /* irq flags */
unsigned int uartclk; /* base uart clock */
diff --git a/include/uapi/asm-generic/ioctls.h b/include/uapi/asm-generic/ioctls.h
index cdc9f4ca8c27..689743366091 100644
--- a/include/uapi/asm-generic/ioctls.h
+++ b/include/uapi/asm-generic/ioctls.h
@@ -106,6 +106,9 @@
# define FIOQSIZE 0x5460
#endif
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Used for packet mode */
#define TIOCPKT_DATA 0
#define TIOCPKT_FLUSHREAD 1
diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
index fa6b16e5fdd8..8cb785ea7087 100644
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -149,4 +149,12 @@ struct serial_iso7816 {
__u32 reserved[5];
};
+struct serial_addr {
+ __u32 flags;
+#define SER_ADDR_RECV (1 << 0)
+#define SER_ADDR_RECV_CLEAR (1 << 1)
+#define SER_ADDR_DEST (1 << 2)
+ __u32 addr;
+};
+
#endif /* _UAPI_LINUX_SERIAL_H */
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 08/12] serial: General support for multipoint addresses
@ 2022-04-11 8:33 ` Ilpo Järvinen
0 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Heikki Krogerus, heiko, linux-sh, James E.J. Bottomley,
Max Filippov, Rich Felker, Paul Mackerras, sparclinux,
linux-arch, Yoshinori Sato, Helge Deller, linux-doc,
Uwe Kleine-König, Ilpo Järvinen, Matt Turner,
linux-xtensa, Arnd Bergmann, Johan Hovold, Ivan Kokshaysky,
Chris Zankel, Thomas Bogendoerfer, linux-parisc, linux-api,
linux-mips, David S. Miller, linux-alpha, linuxppc-dev,
giulio.benetti
Add generic support for serial multipoint addressing. Two new
ioctls are added. TIOCSADDR is used to indicate the
destination/receive address. TIOCGADDR returns the current
address in use. The driver should implement set_addr and get_addr
to support addressing mode.
Adjust ADDRB clearing to happen only if driver does not provide
set_addr (=the driver doesn't support address mode).
This change is necessary for supporting devices with RS485
multipoint addressing [*]. A following patch in the patch series
adds support for Synopsys Designware UART capable for 9th bit
addressing mode. In this mode, 9th bit is used to indicate an
address (byte) within the communication line. The 9th bit
addressing mode is selected using ADDRB introduced by the
previous patch.
Transmit addresses / receiver filter are specified by setting
the flags SER_ADDR_DEST and/or SER_ADDR_RECV. When the user
supplies the transmit address, in the 9bit addressing mode it is
sent out immediately with the 9th bit set to 1. After that, the
subsequent normal data bytes are sent with 9th bit as 0 and they
are intended to the device with the given address. It is up to
receiver to enforce the filter using SER_ADDR_RECV. When userspace
has supplied the receive address, the driver is expected to handle
the matching of the address and only data with that address is
forwarded to the user. Both SER_ADDR_DEST and SER_ADDR_RECV can
be given at the same time in a single call if the addresses are
the same.
The user can clear the receive filter with SER_ADDR_RECV_CLEAR.
[*] 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.
Cc: linux-api@vger.kernel.org
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: linux-alpha@vger.kernel.org
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: linux-mips@vger.kernel.org
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: linux-sh@vger.kernel.org
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
Cc: Chris Zankel <chris@zankel.net>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-xtensa@linux-xtensa.org
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
.../driver-api/serial/serial-rs485.rst | 23 ++++++-
arch/alpha/include/uapi/asm/ioctls.h | 3 +
arch/mips/include/uapi/asm/ioctls.h | 3 +
arch/parisc/include/uapi/asm/ioctls.h | 3 +
arch/powerpc/include/uapi/asm/ioctls.h | 3 +
arch/sh/include/uapi/asm/ioctls.h | 3 +
arch/sparc/include/uapi/asm/ioctls.h | 3 +
arch/xtensa/include/uapi/asm/ioctls.h | 3 +
drivers/tty/serial/8250/8250_core.c | 2 +
drivers/tty/serial/serial_core.c | 62 ++++++++++++++++++-
drivers/tty/tty_io.c | 2 +
include/linux/serial_core.h | 6 ++
include/uapi/asm-generic/ioctls.h | 3 +
include/uapi/linux/serial.h | 8 +++
14 files changed, 125 insertions(+), 2 deletions(-)
diff --git a/Documentation/driver-api/serial/serial-rs485.rst b/Documentation/driver-api/serial/serial-rs485.rst
index 6bc824f948f9..2f45f007fa5b 100644
--- a/Documentation/driver-api/serial/serial-rs485.rst
+++ b/Documentation/driver-api/serial/serial-rs485.rst
@@ -95,7 +95,28 @@ RS485 Serial Communications
/* Error handling. See errno. */
}
-5. References
+5. Multipoint Addressing
+========================
+
+ The Linux kernel provides serial_addr structure to handle addressing within
+ multipoint serial communications line such as RS485. 9th bit addressiong mode
+ is enabled by adding ADDRB flag in termios c_cflag.
+
+ Serial core calls device specific set/get_addr in response to TIOCSADDR and
+ TIOCGADDR ioctls with a pointer to serial_addr. Destination and receive
+ address can be specified using serial_addr flags field. Receive address may
+ also be cleared using flags. Once an address is set, the communication
+ can occur only with the particular device and other peers are filtered out.
+ It is left up to the receiver side to enforce the filtering.
+
+ Address flags:
+ - SER_ADDR_RECV: Receive (filter) address.
+ - SER_ADDR_RECV_CLEAR: Clear receive filter (only for TIOCSADDR).
+ - SER_ADDR_DEST: Destination address.
+
+ Note: not all devices supporting RS485 support multipoint addressing.
+
+6. References
=============
[1] include/uapi/linux/serial.h
diff --git a/arch/alpha/include/uapi/asm/ioctls.h b/arch/alpha/include/uapi/asm/ioctls.h
index 971311605288..500cab3e1d6b 100644
--- a/arch/alpha/include/uapi/asm/ioctls.h
+++ b/arch/alpha/include/uapi/asm/ioctls.h
@@ -125,4 +125,7 @@
#define TIOCMIWAIT 0x545C /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _ASM_ALPHA_IOCTLS_H */
diff --git a/arch/mips/include/uapi/asm/ioctls.h b/arch/mips/include/uapi/asm/ioctls.h
index 16aa8a766aec..3859dc46857e 100644
--- a/arch/mips/include/uapi/asm/ioctls.h
+++ b/arch/mips/include/uapi/asm/ioctls.h
@@ -96,6 +96,9 @@
#define TIOCGISO7816 _IOR('T', 0x42, struct serial_iso7816)
#define TIOCSISO7816 _IOWR('T', 0x43, struct serial_iso7816)
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* I hope the range from 0x5480 on is free ... */
#define TIOCSCTTY 0x5480 /* become controlling tty */
#define TIOCGSOFTCAR 0x5481
diff --git a/arch/parisc/include/uapi/asm/ioctls.h b/arch/parisc/include/uapi/asm/ioctls.h
index 82d1148c6379..62337743db64 100644
--- a/arch/parisc/include/uapi/asm/ioctls.h
+++ b/arch/parisc/include/uapi/asm/ioctls.h
@@ -86,6 +86,9 @@
#define TIOCSTOP 0x5462
#define TIOCSLTC 0x5462
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Used for packet mode */
#define TIOCPKT_DATA 0
#define TIOCPKT_FLUSHREAD 1
diff --git a/arch/powerpc/include/uapi/asm/ioctls.h b/arch/powerpc/include/uapi/asm/ioctls.h
index 2c145da3b774..84fd69ac366a 100644
--- a/arch/powerpc/include/uapi/asm/ioctls.h
+++ b/arch/powerpc/include/uapi/asm/ioctls.h
@@ -120,4 +120,7 @@
#define TIOCMIWAIT 0x545C /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _ASM_POWERPC_IOCTLS_H */
diff --git a/arch/sh/include/uapi/asm/ioctls.h b/arch/sh/include/uapi/asm/ioctls.h
index 11866d4f60e1..f82966b7dba2 100644
--- a/arch/sh/include/uapi/asm/ioctls.h
+++ b/arch/sh/include/uapi/asm/ioctls.h
@@ -113,4 +113,7 @@
#define TIOCMIWAIT _IO('T', 92) /* 0x545C */ /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* __ASM_SH_IOCTLS_H */
diff --git a/arch/sparc/include/uapi/asm/ioctls.h b/arch/sparc/include/uapi/asm/ioctls.h
index 7fd2f5873c9e..e44624c67c79 100644
--- a/arch/sparc/include/uapi/asm/ioctls.h
+++ b/arch/sparc/include/uapi/asm/ioctls.h
@@ -125,6 +125,9 @@
#define TIOCMIWAIT 0x545C /* Wait for change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* Read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Kernel definitions */
/* Used for packet mode */
diff --git a/arch/xtensa/include/uapi/asm/ioctls.h b/arch/xtensa/include/uapi/asm/ioctls.h
index 6d4a87296c95..759ca9377f2a 100644
--- a/arch/xtensa/include/uapi/asm/ioctls.h
+++ b/arch/xtensa/include/uapi/asm/ioctls.h
@@ -127,4 +127,7 @@
#define TIOCMIWAIT _IO('T', 92) /* wait for a change on serial input line(s) */
#define TIOCGICOUNT 0x545D /* read serial port inline interrupt counts */
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
#endif /* _XTENSA_IOCTLS_H */
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 01d30f6ed8fb..f67bc3b76f65 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1008,6 +1008,8 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
uart->port.rs485 = up->port.rs485;
uart->rs485_start_tx = up->rs485_start_tx;
uart->rs485_stop_tx = up->rs485_stop_tx;
+ uart->port.set_addr = up->port.set_addr;
+ uart->port.get_addr = up->port.get_addr;
uart->dma = up->dma;
/* Take tx_loadsz from fifosize if it wasn't set separately */
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index de198c2acefe..2cd129c78ef6 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -1350,6 +1350,56 @@ static int uart_set_iso7816_config(struct uart_port *port,
return 0;
}
+static int uart_set_addr(struct uart_port *port,
+ struct serial_addr __user *serial_addr_user)
+{
+ struct serial_addr addr;
+ unsigned long flags;
+ int ret;
+
+ if (!port->set_addr)
+ return -ENOTTY;
+
+ if (copy_from_user(&addr, serial_addr_user, sizeof(*serial_addr_user)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->set_addr(port, &addr);
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(serial_addr_user, &addr, sizeof(addr)))
+ return -EFAULT;
+
+ return 0;
+}
+
+static int uart_get_addr(struct uart_port *port,
+ struct serial_addr __user *serial_addr_user)
+{
+ struct serial_addr addr;
+ unsigned long flags;
+ int ret;
+
+ if (!port->get_addr)
+ return -ENOTTY;
+
+ if (copy_from_user(&addr, serial_addr_user, sizeof(*serial_addr_user)))
+ return -EFAULT;
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->get_addr(port, &addr);
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
+
+ if (copy_to_user(serial_addr_user, &addr, sizeof(addr)))
+ return -EFAULT;
+
+ return 0;
+}
+
/*
* Called via sys_ioctl. We can use spin_lock_irq() here.
*/
@@ -1427,6 +1477,15 @@ uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
case TIOCGISO7816:
ret = uart_get_iso7816_config(state->uart_port, uarg);
break;
+
+ case TIOCSADDR:
+ ret = uart_set_addr(uport, uarg);
+ break;
+
+ case TIOCGADDR:
+ ret = uart_get_addr(uport, uarg);
+ break;
+
default:
if (uport->ops->ioctl)
ret = uport->ops->ioctl(uport, cmd, arg);
@@ -1493,7 +1552,8 @@ static void uart_set_termios(struct tty_struct *tty,
goto out;
}
- tty->termios.c_cflag &= ~ADDRB;
+ if (!uport->set_addr)
+ tty->termios.c_cflag &= ~ADDRB;
uart_change_speed(tty, state, old_termios);
/* reload cflag from termios; port driver may have overridden flags */
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 7e8b3bd59c7b..93d8609e88aa 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2885,6 +2885,8 @@ static long tty_compat_ioctl(struct file *file, unsigned int cmd,
case TIOCSERGETLSR:
case TIOCGRS485:
case TIOCSRS485:
+ case TIOCSADDR:
+ case TIOCGADDR:
#ifdef TIOCGETP
case TIOCGETP:
case TIOCSETP:
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 504d365e2803..a2efd3fe2635 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -135,6 +135,12 @@ struct uart_port {
struct serial_rs485 *rs485);
int (*iso7816_config)(struct uart_port *,
struct serial_iso7816 *iso7816);
+
+ int (*set_addr)(struct uart_port *p,
+ struct serial_addr *addr);
+ int (*get_addr)(struct uart_port *p,
+ struct serial_addr *addr);
+
unsigned int irq; /* irq number */
unsigned long irqflags; /* irq flags */
unsigned int uartclk; /* base uart clock */
diff --git a/include/uapi/asm-generic/ioctls.h b/include/uapi/asm-generic/ioctls.h
index cdc9f4ca8c27..689743366091 100644
--- a/include/uapi/asm-generic/ioctls.h
+++ b/include/uapi/asm-generic/ioctls.h
@@ -106,6 +106,9 @@
# define FIOQSIZE 0x5460
#endif
+#define TIOCSADDR _IOWR('T', 0x63, struct serial_addr)
+#define TIOCGADDR _IOWR('T', 0x64, struct serial_addr)
+
/* Used for packet mode */
#define TIOCPKT_DATA 0
#define TIOCPKT_FLUSHREAD 1
diff --git a/include/uapi/linux/serial.h b/include/uapi/linux/serial.h
index fa6b16e5fdd8..8cb785ea7087 100644
--- a/include/uapi/linux/serial.h
+++ b/include/uapi/linux/serial.h
@@ -149,4 +149,12 @@ struct serial_iso7816 {
__u32 reserved[5];
};
+struct serial_addr {
+ __u32 flags;
+#define SER_ADDR_RECV (1 << 0)
+#define SER_ADDR_RECV_CLEAR (1 << 1)
+#define SER_ADDR_DEST (1 << 2)
+ __u32 addr;
+};
+
#endif /* _UAPI_LINUX_SERIAL_H */
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread
* [PATCH v3 09/12] serial: 8250: make saved LSR larger
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (7 preceding siblings ...)
2022-04-11 8:33 ` Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 10/12] serial: 8250: create lsr_save_mask Ilpo Järvinen
` (3 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen
DW flags address received as BIT(8) in LSR. In order to not
lose that on read, enlarge lsr_saved_flags and adjust related
call chains which passed chars previously.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250_port.c | 8 ++++----
include/linux/serial_8250.h | 6 +++---
2 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 276c5281aaa0..6e85ad0fade6 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1585,7 +1585,7 @@ static inline void __start_tx(struct uart_port *port)
if (serial8250_set_THRI(up)) {
if (up->bugs & UART_BUG_TXEN) {
- unsigned char lsr;
+ unsigned int lsr;
lsr = serial_in(up, UART_LSR);
up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
@@ -1741,7 +1741,7 @@ static void serial8250_enable_ms(struct uart_port *port)
serial8250_rpm_put(up);
}
-void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr)
+void serial8250_read_char(struct uart_8250_port *up, unsigned int lsr)
{
struct uart_port *port = &up->port;
unsigned char ch;
@@ -1808,7 +1808,7 @@ EXPORT_SYMBOL_GPL(serial8250_read_char);
* value, and returns the remaining LSR bits not handled
* by this Rx routine.
*/
-unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr)
+unsigned int serial8250_rx_chars(struct uart_8250_port *up, unsigned int lsr)
{
struct uart_port *port = &up->port;
int max_count = 256;
@@ -1930,7 +1930,7 @@ static bool handle_rx_dma(struct uart_8250_port *up, unsigned int iir)
*/
int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
{
- unsigned char status;
+ unsigned int status;
struct uart_8250_port *up = up_to_u8250p(port);
bool skip_rx = false;
unsigned long flags;
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index ff84a3ed10ea..921df4c60062 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -119,7 +119,7 @@ struct uart_8250_port {
* be immediately processed.
*/
#define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
- unsigned char lsr_saved_flags;
+ u16 lsr_saved_flags;
#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
unsigned char msr_saved_flags;
@@ -170,8 +170,8 @@ extern void serial8250_do_set_divisor(struct uart_port *port, unsigned int baud,
unsigned int quot_frac);
extern int fsl8250_handle_irq(struct uart_port *port);
int serial8250_handle_irq(struct uart_port *port, unsigned int iir);
-unsigned char serial8250_rx_chars(struct uart_8250_port *up, unsigned char lsr);
-void serial8250_read_char(struct uart_8250_port *up, unsigned char lsr);
+unsigned int serial8250_rx_chars(struct uart_8250_port *up, unsigned int lsr);
+void serial8250_read_char(struct uart_8250_port *up, unsigned int lsr);
void serial8250_tx_chars(struct uart_8250_port *up);
unsigned int serial8250_modem_status(struct uart_8250_port *up);
void serial8250_init_port(struct uart_8250_port *up);
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 10/12] serial: 8250: create lsr_save_mask
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (8 preceding siblings ...)
2022-04-11 8:33 ` [PATCH v3 09/12] serial: 8250: make saved LSR larger Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 8:33 ` [PATCH v3 11/12] serial: 8250_lpss: Use 32-bit reads Ilpo Järvinen
` (2 subsequent siblings)
12 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen
Allow drivers to alter LSR save mask.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250_core.c | 4 +++-
drivers/tty/serial/8250/8250_port.c | 6 +++---
include/linux/serial_8250.h | 1 +
3 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index f67bc3b76f65..7cb1267559d4 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -278,7 +278,7 @@ static void serial8250_backup_timeout(struct timer_list *t)
* ia64 and parisc boxes.
*/
lsr = serial_in(up, UART_LSR);
- up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+ up->lsr_saved_flags |= lsr & up->lsr_save_mask;
if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
(!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
(lsr & UART_LSR_THRE)) {
@@ -1097,6 +1097,8 @@ int serial8250_register_8250_port(const struct uart_8250_port *up)
ret = 0;
}
+ uart->lsr_save_mask = up->lsr_save_mask ?: LSR_SAVE_FLAGS;
+
/* Initialise interrupt backoff work if required */
if (up->overrun_backoff_time_ms > 0) {
uart->overrun_backoff_time_ms =
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 6e85ad0fade6..b3289ef117d1 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1588,7 +1588,7 @@ static inline void __start_tx(struct uart_port *port)
unsigned int lsr;
lsr = serial_in(up, UART_LSR);
- up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+ up->lsr_saved_flags |= lsr & up->lsr_save_mask;
if (lsr & UART_LSR_THRE)
serial8250_tx_chars(up);
}
@@ -2019,7 +2019,7 @@ static unsigned int serial8250_tx_empty(struct uart_port *port)
spin_lock_irqsave(&port->lock, flags);
lsr = serial_port_in(port, UART_LSR);
- up->lsr_saved_flags |= lsr & LSR_SAVE_FLAGS;
+ up->lsr_saved_flags |= lsr & up->lsr_save_mask;
spin_unlock_irqrestore(&port->lock, flags);
serial8250_rpm_put(up);
@@ -2100,7 +2100,7 @@ static void wait_for_xmitr(struct uart_8250_port *up, int bits)
for (;;) {
status = serial_in(up, UART_LSR);
- up->lsr_saved_flags |= status & LSR_SAVE_FLAGS;
+ up->lsr_saved_flags |= status & up->lsr_save_mask;
if ((status & bits) == bits)
break;
diff --git a/include/linux/serial_8250.h b/include/linux/serial_8250.h
index 921df4c60062..aff76ea22287 100644
--- a/include/linux/serial_8250.h
+++ b/include/linux/serial_8250.h
@@ -120,6 +120,7 @@ struct uart_8250_port {
*/
#define LSR_SAVE_FLAGS UART_LSR_BRK_ERROR_BITS
u16 lsr_saved_flags;
+ u16 lsr_save_mask;
#define MSR_SAVE_FLAGS UART_MSR_ANY_DELTA
unsigned char msr_saved_flags;
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* [PATCH v3 11/12] serial: 8250_lpss: Use 32-bit reads
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (9 preceding siblings ...)
2022-04-11 8:33 ` [PATCH v3 10/12] serial: 8250: create lsr_save_mask Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 11:12 ` Andy Shevchenko
2022-04-11 8:33 ` [PATCH v3 12/12] serial: 8250_dwlib: Support for 9th bit multipoint addressing Ilpo Järvinen
2022-04-21 15:36 ` [PATCH v3 00/12] Add RS485 support to DW UART Vicente Bergas
12 siblings, 1 reply; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen
Use 32-bit reads in order to not lose higher bits of DW
UART regs.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250_lpss.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index 0f5af061e0b4..4ba43bef9933 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -330,7 +330,7 @@ static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
uart.port.irq = pci_irq_vector(pdev, 0);
uart.port.private_data = &lpss->data;
uart.port.type = PORT_16550A;
- uart.port.iotype = UPIO_MEM;
+ uart.port.iotype = UPIO_MEM32;
uart.port.regshift = 2;
uart.port.uartclk = lpss->board->base_baud * 16;
uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* Re: [PATCH v3 11/12] serial: 8250_lpss: Use 32-bit reads
2022-04-11 8:33 ` [PATCH v3 11/12] serial: 8250_lpss: Use 32-bit reads Ilpo Järvinen
@ 2022-04-11 11:12 ` Andy Shevchenko
0 siblings, 0 replies; 30+ messages in thread
From: Andy Shevchenko @ 2022-04-11 11:12 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Johan Hovold,
heiko, giulio.benetti, Heikki Krogerus, Uwe Kleine-König
On Mon, Apr 11, 2022 at 11:33:20AM +0300, Ilpo Järvinen wrote:
> Use 32-bit reads in order to not lose higher bits of DW
> UART regs.
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Maybe it needs an additional words that currently the driver doesn't
use anything from the upper bits, that's why it's not a fix.
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> ---
> drivers/tty/serial/8250/8250_lpss.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
> index 0f5af061e0b4..4ba43bef9933 100644
> --- a/drivers/tty/serial/8250/8250_lpss.c
> +++ b/drivers/tty/serial/8250/8250_lpss.c
> @@ -330,7 +330,7 @@ static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> uart.port.irq = pci_irq_vector(pdev, 0);
> uart.port.private_data = &lpss->data;
> uart.port.type = PORT_16550A;
> - uart.port.iotype = UPIO_MEM;
> + uart.port.iotype = UPIO_MEM32;
> uart.port.regshift = 2;
> uart.port.uartclk = lpss->board->base_baud * 16;
> uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
> --
> 2.30.2
>
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 30+ messages in thread
* [PATCH v3 12/12] serial: 8250_dwlib: Support for 9th bit multipoint addressing
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (10 preceding siblings ...)
2022-04-11 8:33 ` [PATCH v3 11/12] serial: 8250_lpss: Use 32-bit reads Ilpo Järvinen
@ 2022-04-11 8:33 ` Ilpo Järvinen
2022-04-11 11:19 ` Andy Shevchenko
2022-04-21 15:36 ` [PATCH v3 00/12] Add RS485 support to DW UART Vicente Bergas
12 siblings, 1 reply; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-11 8:33 UTC (permalink / raw)
To: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Andy Shevchenko
Cc: Johan Hovold, heiko, giulio.benetti, Heikki Krogerus,
Uwe Kleine-König, Ilpo Järvinen, Raymond Tan,
Lakshmi Sowjanya
This change adds 9th bit multipoint addressing mode for DW UART using
the new ioctls introduced in the previous change. 9th bit addressing
can be used only when HW RS485 is available.
Updating RAR (receive address register) is bit tricky because
busy indication is not be available when DW UART is strictly
16550 compatible, which is the case with the hardware I was
testing with. RAR should not be updated while receive is in
progress which is now achieved by deasserting RE and waiting
for one frame (in case rx would be in progress, the driver
seems to have no way of knowing it w/o busy indication).
Co-developed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Co-developed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Co-developed-by: Raymond Tan <raymond.tan@intel.com>
Signed-off-by: Raymond Tan <raymond.tan@intel.com>
Co-developed-by: Lakshmi Sowjanya <lakshmi.sowjanya.d@intel.com>
Signed-off-by: Lakshmi Sowjanya <lakshmi.sowjanya.d@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250_dwlib.c | 139 +++++++++++++++++++++++++++
drivers/tty/serial/8250/8250_dwlib.h | 2 +
2 files changed, 141 insertions(+)
diff --git a/drivers/tty/serial/8250/8250_dwlib.c b/drivers/tty/serial/8250/8250_dwlib.c
index 04852af4c024..ab4b42cdeb03 100644
--- a/drivers/tty/serial/8250/8250_dwlib.c
+++ b/drivers/tty/serial/8250/8250_dwlib.c
@@ -3,9 +3,11 @@
#include <linux/bitops.h>
#include <linux/bitfield.h>
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
+#include <linux/math.h>
#include <linux/property.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
@@ -17,9 +19,15 @@
#define DW_UART_DE_EN 0xb0 /* Driver Output Enable Register */
#define DW_UART_RE_EN 0xb4 /* Receiver Output Enable Register */
#define DW_UART_DLF 0xc0 /* Divisor Latch Fraction Register */
+#define DW_UART_RAR 0xc4 /* Receive Address Register */
+#define DW_UART_TAR 0xc8 /* Transmit Address Register */
+#define DW_UART_LCR_EXT 0xcc /* Line Extended Control Register */
#define DW_UART_CPR 0xf4 /* Component Parameter Register */
#define DW_UART_UCV 0xf8 /* UART Component Version */
+/* Line Status Register bits */
+#define DW_UART_LSR_ADDR_RCVD BIT(8)
+
/* Transceiver Control Register bits */
#define DW_UART_TCR_RS485_EN BIT(0)
#define DW_UART_TCR_RE_POL BIT(1)
@@ -29,6 +37,12 @@
#define DW_UART_TCR_XFER_MODE_SW_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 1)
#define DW_UART_TCR_XFER_MODE_DE_OR_RE FIELD_PREP(DW_UART_TCR_XFER_MODE, 2)
+/* Line Extended Control Register bits */
+#define DW_UART_LCR_EXT_DLS_E BIT(0)
+#define DW_UART_LCR_EXT_ADDR_MATCH BIT(1)
+#define DW_UART_LCR_EXT_SEND_ADDR BIT(2)
+#define DW_UART_LCR_EXT_TRANSMIT_MODE BIT(3)
+
/* Component Parameter Register bits */
#define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0)
#define DW_UART_CPR_AFCE_MODE (1 << 4)
@@ -91,18 +105,132 @@ static void dw8250_set_divisor(struct uart_port *p, unsigned int baud,
serial8250_do_set_divisor(p, baud, quot, quot_frac);
}
+/*
+ * Wait until re is de-asserted for sure. An ongoing receive will keep
+ * re asserted until end of frame. Without BUSY indication available,
+ * only available course of action is to wait for the time it takes to
+ * receive one frame (there might nothing to receive but w/o BUSY the
+ * driver cannot know).
+ */
+static void dw8250_wait_re_deassert(struct uart_port *p)
+{
+ udelay(p->frame_time);
+}
+
+static void dw8250_update_rar(struct uart_port *p, u32 addr)
+{
+ u32 re_en = dw8250_readl_ext(p, DW_UART_RE_EN);
+
+ /*
+ * RAR shouldn't be changed while receiving. Thus, de-assert RE_EN
+ * if asserted and wait.
+ */
+ if (re_en)
+ dw8250_writel_ext(p, DW_UART_RE_EN, 0);
+ dw8250_wait_re_deassert(p);
+ dw8250_writel_ext(p, DW_UART_RAR, addr);
+ if (re_en)
+ dw8250_writel_ext(p, DW_UART_RE_EN, re_en);
+}
+
+static void dw8250_addrmode_setup(struct uart_port *p, bool enable_addrmode)
+{
+ struct dw8250_port_data *d = p->private_data;
+
+ if (enable_addrmode) {
+ /* Clear RAR & TAR of any previous values */
+ dw8250_writel_ext(p, DW_UART_RAR, 0);
+ dw8250_writel_ext(p, DW_UART_TAR, 0);
+ dw8250_writel_ext(p, DW_UART_LCR_EXT, DW_UART_LCR_EXT_DLS_E);
+ } else {
+ dw8250_writel_ext(p, DW_UART_LCR_EXT, 0);
+ }
+
+ d->addrmode = enable_addrmode;
+}
+
void dw8250_do_set_termios(struct uart_port *p, struct ktermios *termios, struct ktermios *old)
{
+ struct dw8250_port_data *d = p->private_data;
+
p->status &= ~UPSTAT_AUTOCTS;
if (termios->c_cflag & CRTSCTS)
p->status |= UPSTAT_AUTOCTS;
+ if (!(p->rs485.flags & SER_RS485_ENABLED) || !d->hw_rs485_support)
+ termios->c_cflag &= ~ADDRB;
+
+ if (!old || (termios->c_cflag ^ old->c_cflag) & ADDRB)
+ dw8250_addrmode_setup(p, termios->c_cflag & ADDRB);
+
serial8250_do_set_termios(p, termios, old);
+
+ if (d->addrmode) {
+ p->ignore_status_mask |= DW_UART_LSR_ADDR_RCVD;
+ p->read_status_mask |= DW_UART_LSR_ADDR_RCVD;
+ }
}
EXPORT_SYMBOL_GPL(dw8250_do_set_termios);
+static int dw8250_rs485_set_addr(struct uart_port *p, struct serial_addr *addr)
+{
+ struct dw8250_port_data *d = p->private_data;
+ u32 lcr;
+
+ if (!(p->rs485.flags & SER_RS485_ENABLED) || !d->addrmode)
+ return -EINVAL;
+
+ addr->flags &= SER_ADDR_RECV | SER_ADDR_RECV_CLEAR | SER_ADDR_DEST;
+ if (!addr->flags)
+ return -EINVAL;
+
+ lcr = dw8250_readl_ext(p, DW_UART_LCR_EXT);
+ if (addr->flags & SER_ADDR_RECV) {
+ dw8250_update_rar(p, addr->addr & 0xff);
+ lcr |= DW_UART_LCR_EXT_ADDR_MATCH;
+ addr->flags &= ~SER_ADDR_RECV_CLEAR;
+ } else if (addr->flags & SER_ADDR_RECV_CLEAR) {
+ lcr &= DW_UART_LCR_EXT_ADDR_MATCH;
+ }
+ if (addr->flags & SER_ADDR_DEST) {
+ dw8250_writel_ext(p, DW_UART_TAR, addr->addr & 0xff);
+ lcr |= DW_UART_LCR_EXT_SEND_ADDR;
+ }
+ dw8250_writel_ext(p, DW_UART_LCR_EXT, lcr);
+
+ return 0;
+}
+
+static int dw8250_rs485_get_addr(struct uart_port *p, struct serial_addr *addr)
+{
+ struct dw8250_port_data *d = p->private_data;
+
+ if (!(p->rs485.flags & SER_RS485_ENABLED) || !d->addrmode)
+ return -EINVAL;
+
+ if (addr->flags == SER_ADDR_DEST) {
+ addr->addr = dw8250_readl_ext(p, DW_UART_TAR) & 0xff;
+ return 0;
+ }
+ if (addr->flags == SER_ADDR_RECV) {
+ u32 lcr = dw8250_readl_ext(p, DW_UART_LCR_EXT);
+
+ if (!(lcr & DW_UART_LCR_EXT_ADDR_MATCH)) {
+ addr->flags = SER_ADDR_RECV_CLEAR;
+ addr->addr = 0;
+ } else {
+ addr->addr = dw8250_readl_ext(p, DW_UART_RAR) & 0xff;
+ }
+
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
static int dw8250_rs485_config(struct uart_port *p, struct serial_rs485 *rs485)
{
+ struct dw8250_port_data *d = p->private_data;
u32 tcr;
tcr = dw8250_readl_ext(p, DW_UART_TCR);
@@ -127,6 +255,14 @@ static int dw8250_rs485_config(struct uart_port *p, struct serial_rs485 *rs485)
dw8250_writel_ext(p, DW_UART_DE_EN, 1);
dw8250_writel_ext(p, DW_UART_RE_EN, 1);
} else {
+ /*
+ * Don't allow disabling RS485 when address mode is enabled.
+ * Clearing address mode would require clearing ADDRB in
+ * termios.
+ */
+ if (d->addrmode)
+ return -EINVAL;
+
rs485->flags = 0;
tcr &= ~DW_UART_TCR_RS485_EN;
@@ -174,6 +310,9 @@ void dw8250_setup_port(struct uart_port *p)
d->hw_rs485_support = dw8250_detect_rs485_hw(p);
if (d->hw_rs485_support) {
p->rs485_config = dw8250_rs485_config;
+ p->set_addr = dw8250_rs485_set_addr;
+ p->get_addr = dw8250_rs485_get_addr;
+ up->lsr_save_mask = LSR_SAVE_FLAGS | DW_UART_LSR_ADDR_RCVD;
} else {
p->rs485_config = serial8250_em485_config;
up->rs485_start_tx = serial8250_em485_start_tx;
diff --git a/drivers/tty/serial/8250/8250_dwlib.h b/drivers/tty/serial/8250/8250_dwlib.h
index a8fa020ca544..c616d5b29f66 100644
--- a/drivers/tty/serial/8250/8250_dwlib.h
+++ b/drivers/tty/serial/8250/8250_dwlib.h
@@ -17,6 +17,8 @@ struct dw8250_port_data {
/* RS485 variables */
bool hw_rs485_support;
+ /* 9-bit framing (9th bit is address indicator) */
+ bool addrmode;
};
void dw8250_do_set_termios(struct uart_port *p, struct ktermios *termios, struct ktermios *old);
--
2.30.2
^ permalink raw reply related [flat|nested] 30+ messages in thread* Re: [PATCH v3 12/12] serial: 8250_dwlib: Support for 9th bit multipoint addressing
2022-04-11 8:33 ` [PATCH v3 12/12] serial: 8250_dwlib: Support for 9th bit multipoint addressing Ilpo Järvinen
@ 2022-04-11 11:19 ` Andy Shevchenko
0 siblings, 0 replies; 30+ messages in thread
From: Andy Shevchenko @ 2022-04-11 11:19 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: linux-serial, Greg KH, Jiri Slaby, Lukas Wunner, Johan Hovold,
heiko, giulio.benetti, Heikki Krogerus, Uwe Kleine-König,
Raymond Tan, Lakshmi Sowjanya
On Mon, Apr 11, 2022 at 11:33:21AM +0300, Ilpo Järvinen wrote:
> This change adds 9th bit multipoint addressing mode for DW UART using
> the new ioctls introduced in the previous change. 9th bit addressing
> can be used only when HW RS485 is available.
>
> Updating RAR (receive address register) is bit tricky because
> busy indication is not be available when DW UART is strictly
> 16550 compatible, which is the case with the hardware I was
> testing with. RAR should not be updated while receive is in
> progress which is now achieved by deasserting RE and waiting
> for one frame (in case rx would be in progress, the driver
> seems to have no way of knowing it w/o busy indication).
...
> +static void dw8250_update_rar(struct uart_port *p, u32 addr)
> +{
> + u32 re_en = dw8250_readl_ext(p, DW_UART_RE_EN);
> +
> + /*
> + * RAR shouldn't be changed while receiving. Thus, de-assert RE_EN
> + * if asserted and wait.
> + */
> + if (re_en)
> + dw8250_writel_ext(p, DW_UART_RE_EN, 0);
> + dw8250_wait_re_deassert(p);
> + dw8250_writel_ext(p, DW_UART_RAR, addr);
> + if (re_en)
> + dw8250_writel_ext(p, DW_UART_RE_EN, re_en);
I would write it
u32 re_en;
/*
* RAR shouldn't be changed while receiving. Thus, de-assert RE_EN
* if asserted and wait.
*/
re_en = dw8250_readl_ext(p, DW_UART_RE_EN);
if (re_en) {
dw8250_writel_ext(p, DW_UART_RE_EN, 0);
dw8250_wait_re_deassert(p);
dw8250_writel_ext(p, DW_UART_RAR, addr);
dw8250_writel_ext(p, DW_UART_RE_EN, re_en);
} else {
dw8250_wait_re_deassert(p);
dw8250_writel_ext(p, DW_UART_RAR, addr);
}
or something similar with extracting these two lines into another function.
But it's up to you, it's just pure style thingy.
> +}
...
> + dw8250_writel_ext(p, DW_UART_TAR, addr->addr & 0xff);
GENMASK() ?
Perhaps even a separate definition?
...
> + addr->addr = dw8250_readl_ext(p, DW_UART_TAR) & 0xff;
Ditto.
...
> + addr->addr = dw8250_readl_ext(p, DW_UART_RAR) & 0xff;
Ditto.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v3 00/12] Add RS485 support to DW UART
2022-04-11 8:33 [PATCH v3 00/12] Add RS485 support to DW UART Ilpo Järvinen
` (11 preceding siblings ...)
2022-04-11 8:33 ` [PATCH v3 12/12] serial: 8250_dwlib: Support for 9th bit multipoint addressing Ilpo Järvinen
@ 2022-04-21 15:36 ` Vicente Bergas
2022-04-21 19:38 ` Lukas Wunner
2022-04-22 9:25 ` Ilpo Järvinen
12 siblings, 2 replies; 30+ messages in thread
From: Vicente Bergas @ 2022-04-21 15:36 UTC (permalink / raw)
To: ilpo.jarvinen
Cc: andriy.shevchenko, giulio.benetti, gregkh, heikki.krogerus,
heiko, jirislaby, johan, linux-api, linux-serial, lukas,
u.kleine-koenig
Hello Ilpo,
i have tested your v3 patch on v3 hardware, that is, using the
emulated em485 because of lack of HW support. It is not working
due to three issues.
1.- rs485_stop_tx is never called because there are no interrupts.
I worked around this by disabling DMA:
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -577,3 +577,3 @@ static int dw8250_probe(struct platform_device *pdev)
data->data.dma.rxconf.src_maxburst = p->fifosize / 4;
data->data.dma.txconf.dst_maxburst = p->fifosize / 4;
- up->dma = &data->data.dma;
+ up->dma = 0; // Proof of concept, not to be merged!
2.- Although "linux,rs485-enabled-at-boot-time" is set in the DTS,
the RTS/DriverEnable line is asserted all the time the /dev/ttyS1
device file is closed.
As soon as the device file is openned, the RTS line is deasserted.
Then it works as expected: it is asserted only during transmissions.
When the device file is closed again, the RTS line goes back to the
asserted level and stays there.
When the rs485 mode is enabled, it is expected that the RTS line be
deasserted by default.
3.- The RTS line is asserted a few microseconds earlier than the
start bit, that is acceptable, but then it deasserts one whole bit
time before the last stop bit.
So, the last stop bit of the last byte of a message is not sent
because the driver is disabled.
This has been tested with the port configured at 19200e1, that is,
the bit time is 52 us.
I worked around this by adding "rs485-rts-delay = <0 52>;" in the
DTS. This leads to the following feature (not an issue):
On Mon, 11 Apr 2022 11:33:12 +0300, Ilpo Järvinen wrote:
> Set delay_rts_before_send and delay_rts_after_send to zero for now.
> The granularity of that ABI is too coarse to be useful.
Indeed the time unit of this parameter is milliseconds, as stated in
Documentation/devicetree/bindings/serial/rs485.yaml
Which in the general case is more than ten bit times.
But it is being interpreted as microseconds here:
On Mon, 11 Apr 2022 11:33:11 +0300, Ilpo Järvinen wrote:
> [PATCH v3 02/12] serial: 8250: Handle UART without interrupt on TEMT
>+ stop_delay += (u64)p->port.rs485.delay_rts_after_send * NSEC_PER_USEC;
So, this way it has a useful granularity to be used in
"rs485-rts-delay = <0 52>;" but is not compliant with the spec.
Regards,
Vicente.
^ permalink raw reply [flat|nested] 30+ messages in thread* Re: [PATCH v3 00/12] Add RS485 support to DW UART
2022-04-21 15:36 ` [PATCH v3 00/12] Add RS485 support to DW UART Vicente Bergas
@ 2022-04-21 19:38 ` Lukas Wunner
2022-04-21 20:41 ` Vicente Bergas
2022-04-22 9:25 ` Ilpo Järvinen
1 sibling, 1 reply; 30+ messages in thread
From: Lukas Wunner @ 2022-04-21 19:38 UTC (permalink / raw)
To: Vicente Bergas
Cc: ilpo.jarvinen, andriy.shevchenko, giulio.benetti, gregkh,
heikki.krogerus, heiko, jirislaby, johan, linux-api,
linux-serial, u.kleine-koenig
On Thu, Apr 21, 2022 at 05:36:26PM +0200, Vicente Bergas wrote:
> 2.- Although "linux,rs485-enabled-at-boot-time" is set in the DTS,
> the RTS/DriverEnable line is asserted all the time the /dev/ttyS1
> device file is closed.
> As soon as the device file is openned, the RTS line is deasserted.
> Then it works as expected: it is asserted only during transmissions.
> When the device file is closed again, the RTS line goes back to the
> asserted level and stays there.
> When the rs485 mode is enabled, it is expected that the RTS line be
> deasserted by default.
That's probably the same issue as reported here:
https://lore.kernel.org/linux-serial/20220329085050.311408-1-matthias.schiffer@ew.tq-group.com/
Basically, some drivers have historically used inverse RTS polarity
and others haven't. I'm still busy sorting out which drivers use
which. Sorry, this is quite complex and takes some time.
Have you configured "rs485-rts-active-low" in the device tree?
Which kernel version are you using exactly?
Thanks,
Lukas
^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v3 00/12] Add RS485 support to DW UART
2022-04-21 19:38 ` Lukas Wunner
@ 2022-04-21 20:41 ` Vicente Bergas
0 siblings, 0 replies; 30+ messages in thread
From: Vicente Bergas @ 2022-04-21 20:41 UTC (permalink / raw)
To: Lukas Wunner
Cc: ilpo.jarvinen, Andy Shevchenko, giulio.benetti,
Greg Kroah-Hartman, heikki.krogerus, Heiko Stübner,
jirislaby, johan, linux-api, linux-serial, Uwe Kleine-König
Hi Lukas,
On Thu, Apr 21, 2022 at 9:38 PM Lukas Wunner <lukas@wunner.de> wrote:
>
> On Thu, Apr 21, 2022 at 05:36:26PM +0200, Vicente Bergas wrote:
> > 2.- Although "linux,rs485-enabled-at-boot-time" is set in the DTS,
> > the RTS/DriverEnable line is asserted all the time the /dev/ttyS1
> > device file is closed.
> > As soon as the device file is openned, the RTS line is deasserted.
> > Then it works as expected: it is asserted only during transmissions.
> > When the device file is closed again, the RTS line goes back to the
> > asserted level and stays there.
> > When the rs485 mode is enabled, it is expected that the RTS line be
> > deasserted by default.
>
> That's probably the same issue as reported here:
>
> https://lore.kernel.org/linux-serial/20220329085050.311408-1-matthias.schiffer@ew.tq-group.com/
>
> Basically, some drivers have historically used inverse RTS polarity
> and others haven't. I'm still busy sorting out which drivers use
> which. Sorry, this is quite complex and takes some time.
>
> Have you configured "rs485-rts-active-low" in the device tree?
The UART configuration is the default from rk3328.dtsi plus:
&uart1 {
linux,rs485-enabled-at-boot-time;
pinctrl-0 = <&uart1_xfer &uart1_cts &uart1_rts_pin>;
rs485-rts-delay = <0 52>;
rs485-rx-during-tx;
rts-gpios = <&gpio3 RK_PA5 GPIO_ACTIVE_HIGH>;
status = "okay";
};
So, it is asserted high and deasserted low.
> Which kernel version are you using exactly?
5.17.3 and 5.17.4
Also, i am about to test 5.18-rc3
> Thanks,
>
> Lukas
Regards,
Vicente.
^ permalink raw reply [flat|nested] 30+ messages in thread
* Re: [PATCH v3 00/12] Add RS485 support to DW UART
2022-04-21 15:36 ` [PATCH v3 00/12] Add RS485 support to DW UART Vicente Bergas
2022-04-21 19:38 ` Lukas Wunner
@ 2022-04-22 9:25 ` Ilpo Järvinen
2022-04-22 13:07 ` Ilpo Järvinen
1 sibling, 1 reply; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-22 9:25 UTC (permalink / raw)
To: Vicente Bergas
Cc: Andy Shevchenko, giulio.benetti, gregkh, heikki.krogerus, heiko,
jirislaby, johan, linux-api, linux-serial, lukas,
u.kleine-koenig
[-- Attachment #1: Type: text/plain, Size: 3972 bytes --]
On Thu, 21 Apr 2022, Vicente Bergas wrote:
> i have tested your v3 patch on v3 hardware, that is, using the
> emulated em485 because of lack of HW support. It is not working
> due to three issues.
Thanks for testing!
> 1.- rs485_stop_tx is never called because there are no interrupts.
> I worked around this by disabling DMA:
>
> --- a/drivers/tty/serial/8250/8250_dw.c
> +++ b/drivers/tty/serial/8250/8250_dw.c
> @@ -577,3 +577,3 @@ static int dw8250_probe(struct platform_device *pdev)
> data->data.dma.rxconf.src_maxburst = p->fifosize / 4;
> data->data.dma.txconf.dst_maxburst = p->fifosize / 4;
> - up->dma = &data->data.dma;
> + up->dma = 0; // Proof of concept, not to be merged!
I'll need to look into this.
> 2.- Although "linux,rs485-enabled-at-boot-time" is set in the DTS,
> the RTS/DriverEnable line is asserted all the time the /dev/ttyS1
> device file is closed.
> As soon as the device file is openned, the RTS line is deasserted.
> Then it works as expected: it is asserted only during transmissions.
> When the device file is closed again, the RTS line goes back to the
> asserted level and stays there.
> When the rs485 mode is enabled, it is expected that the RTS line be
> deasserted by default.
Managing RTS is a mess in 8250 driver as has recently being noted. It will
hopefully get sorted out eventually.
> 3.- The RTS line is asserted a few microseconds earlier than the
> start bit, that is acceptable, but then it deasserts one whole bit
> time before the last stop bit.
> So, the last stop bit of the last byte of a message is not sent
> because the driver is disabled.
> This has been tested with the port configured at 19200e1, that is,
> the bit time is 52 us.
> I worked around this by adding "rs485-rts-delay = <0 52>;" in the
> DTS. This leads to the following feature (not an issue):
>
> On Mon, 11 Apr 2022 11:33:12 +0300, Ilpo Järvinen wrote:
> > Set delay_rts_before_send and delay_rts_after_send to zero for now.
> > The granularity of that ABI is too coarse to be useful.
>
> Indeed the time unit of this parameter is milliseconds, as stated in
> Documentation/devicetree/bindings/serial/rs485.yaml
> Which in the general case is more than ten bit times.
>
> But it is being interpreted as microseconds here:
>
> On Mon, 11 Apr 2022 11:33:11 +0300, Ilpo Järvinen wrote:
> > [PATCH v3 02/12] serial: 8250: Handle UART without interrupt on TEMT
> >+ stop_delay += (u64)p->port.rs485.delay_rts_after_send * NSEC_PER_USEC;
>
> So, this way it has a useful granularity to be used in
> "rs485-rts-delay = <0 52>;" but is not compliant with the spec.
It seems I just got confused here with all these different time units. My
intention was to use NSEC_PER_MSEC here to match the spec although it's
not that useful granularity. I'll change that for the next version.
Lukas was planning of making it much finer granularity with nsecs (leaving
the small values for msecs for compat purposes) which would hopefully
resolve this granularity challenge.
About the actual issue of too early deassert. It kind of sounds like the
stop tx timer was not waiting long enough. It could be that THRE is
asserted sooner than I expected (maybe HW does FIFO->shift register
during the transmission of the stop bit of the prev char asserting THRE
approx one bit too early).
Perhaps this patch would help to combat the problem (roughly estimating
worst-case one bit time here with that /7):
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index 35fbaa53bc2f..f944c639db82 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1551,7 +1551,7 @@ static inline void __stop_tx(struct uart_8250_port *p)
if (!(lsr & UART_LSR_TEMT)) {
if (!(p->capabilities & UART_CAP_NOTEMT))
return;
- stop_delay = p->port.frame_time;
+ stop_delay = p->port.frame_time + DIV_ROUND_UP(p->port.frame_time, 7);
}
__stop_tx_rs485(p, stop_delay);
^ permalink raw reply related [flat|nested] 30+ messages in thread* Re: [PATCH v3 00/12] Add RS485 support to DW UART
2022-04-22 9:25 ` Ilpo Järvinen
@ 2022-04-22 13:07 ` Ilpo Järvinen
2022-04-23 23:57 ` Vicente Bergas
0 siblings, 1 reply; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-22 13:07 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: Vicente Bergas, Andy Shevchenko, giulio.benetti, gregkh,
heikki.krogerus, heiko, jirislaby, johan, linux-api,
linux-serial, lukas, u.kleine-koenig
[-- Attachment #1: Type: text/plain, Size: 3341 bytes --]
On Fri, 22 Apr 2022, Ilpo Järvinen wrote:
> On Thu, 21 Apr 2022, Vicente Bergas wrote:
>
> > i have tested your v3 patch on v3 hardware, that is, using the
> > emulated em485 because of lack of HW support. It is not working
> > due to three issues.
>
> Thanks for testing!
>
> > 1.- rs485_stop_tx is never called because there are no interrupts.
> > I worked around this by disabling DMA:
> >
> > --- a/drivers/tty/serial/8250/8250_dw.c
> > +++ b/drivers/tty/serial/8250/8250_dw.c
> > @@ -577,3 +577,3 @@ static int dw8250_probe(struct platform_device *pdev)
> > data->data.dma.rxconf.src_maxburst = p->fifosize / 4;
> > data->data.dma.txconf.dst_maxburst = p->fifosize / 4;
> > - up->dma = &data->data.dma;
> > + up->dma = 0; // Proof of concept, not to be merged!
>
> I'll need to look into this.
8250 DMA tx complete path lacks calls to normal 8250 stop handling and
I think it probably also assumes too much from dmaengine's completion
callback. ...It also seems bit early to call serial8250_rpm_put_tx from
there(?).
This patch allowed em485_start/stop_tx to be called in my tests:
[PATCH 1/1] serial: 8250: use THRE & __stop_tx also with DMA
Currently, DMA complete handling in 8250 driver does not use THRE
to detect true completion of the tx and also doesn't call __stop_tx.
This leads to problems with em485 that needs to handle RTS timing.
Instead of handling tx stop within 8250 dma code, enable THRE when
tx data runs out and tweak serial8250_handle_irq to call
__stop_tx when uart is using DMA.
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
drivers/tty/serial/8250/8250_dma.c | 4 ++--
drivers/tty/serial/8250/8250_port.c | 9 ++++++---
2 files changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
index 890fa7ddaa7f..e84db0abf365 100644
--- a/drivers/tty/serial/8250/8250_dma.c
+++ b/drivers/tty/serial/8250/8250_dma.c
@@ -29,12 +29,13 @@ static void __dma_tx_complete(void *param)
xmit->tail += dma->tx_size;
xmit->tail &= UART_XMIT_SIZE - 1;
p->port.icount.tx += dma->tx_size;
+ dma->tx_size = 0;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&p->port);
ret = serial8250_tx_dma(p);
- if (ret)
+ if (ret || !dma->tx_size)
serial8250_set_THRI(p);
spin_unlock_irqrestore(&p->port.lock, flags);
@@ -71,7 +72,6 @@ int serial8250_tx_dma(struct uart_8250_port *p)
if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
/* We have been called from __dma_tx_complete() */
- serial8250_rpm_put_tx(p);
return 0;
}
diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
index b3289ef117d1..72f144449ee1 100644
--- a/drivers/tty/serial/8250/8250_port.c
+++ b/drivers/tty/serial/8250/8250_port.c
@@ -1960,9 +1960,12 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
status = serial8250_rx_chars(up, status);
}
serial8250_modem_status(up);
- if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE) &&
- (up->ier & UART_IER_THRI))
- serial8250_tx_chars(up);
+ if ((status & UART_LSR_THRE) && (up->ier & UART_IER_THRI)) {
+ if (!up->dma || up->dma->tx_err)
+ serial8250_tx_chars(up);
+ else
+ __stop_tx(up);
+ }
uart_unlock_and_check_sysrq_irqrestore(port, flags);
--
2.35.1
^ permalink raw reply related [flat|nested] 30+ messages in thread* Re: [PATCH v3 00/12] Add RS485 support to DW UART
2022-04-22 13:07 ` Ilpo Järvinen
@ 2022-04-23 23:57 ` Vicente Bergas
2022-04-25 11:16 ` Ilpo Järvinen
0 siblings, 1 reply; 30+ messages in thread
From: Vicente Bergas @ 2022-04-23 23:57 UTC (permalink / raw)
To: Ilpo Järvinen
Cc: Andy Shevchenko, giulio.benetti, Greg Kroah-Hartman,
heikki.krogerus, Heiko Stübner, jirislaby, johan, linux-api,
linux-serial, Lukas Wunner, Uwe Kleine-König
Hi Ilpo, thank you for your quick reply with a solution!
On Fri, Apr 22, 2022 at 3:07 PM Ilpo Järvinen
<ilpo.jarvinen@linux.intel.com> wrote:
>
> On Fri, 22 Apr 2022, Ilpo Järvinen wrote:
>
> > On Thu, 21 Apr 2022, Vicente Bergas wrote:
> >
> > > 1.- rs485_stop_tx is never called because there are no interrupts.
> > > I worked around this by disabling DMA:
> >
> > I'll need to look into this.
>
> 8250 DMA tx complete path lacks calls to normal 8250 stop handling and
> I think it probably also assumes too much from dmaengine's completion
> callback. ...It also seems bit early to call serial8250_rpm_put_tx from
> there(?).
>
> This patch allowed em485_start/stop_tx to be called in my tests:
> [PATCH 1/1] serial: 8250: use THRE & __stop_tx also with DMA
I confirm that this patch fixes the issue when DMA is enabled.
I also confirm that your other patch
> + stop_delay = p->port.frame_time + DIV_ROUND_UP(p->port.frame_time, 7);
fixes the issue with RTS/DriverEnable deassertion time.
I've tested it again at 19200e1 and now RTS is deasserted
approximately at the same time as the end of the stop bit.
Please, note the "e" for even parity bit, that extra bit after the
data byte might have an impact on this timings.
Regards,
Vicente.
On Fri, Apr 22, 2022 at 3:07 PM Ilpo Järvinen
<ilpo.jarvinen@linux.intel.com> wrote:
>
> On Fri, 22 Apr 2022, Ilpo Järvinen wrote:
>
> > On Thu, 21 Apr 2022, Vicente Bergas wrote:
> >
> > > i have tested your v3 patch on v3 hardware, that is, using the
> > > emulated em485 because of lack of HW support. It is not working
> > > due to three issues.
> >
> > Thanks for testing!
> >
> > > 1.- rs485_stop_tx is never called because there are no interrupts.
> > > I worked around this by disabling DMA:
> > >
> > > --- a/drivers/tty/serial/8250/8250_dw.c
> > > +++ b/drivers/tty/serial/8250/8250_dw.c
> > > @@ -577,3 +577,3 @@ static int dw8250_probe(struct platform_device *pdev)
> > > data->data.dma.rxconf.src_maxburst = p->fifosize / 4;
> > > data->data.dma.txconf.dst_maxburst = p->fifosize / 4;
> > > - up->dma = &data->data.dma;
> > > + up->dma = 0; // Proof of concept, not to be merged!
> >
> > I'll need to look into this.
>
> 8250 DMA tx complete path lacks calls to normal 8250 stop handling and
> I think it probably also assumes too much from dmaengine's completion
> callback. ...It also seems bit early to call serial8250_rpm_put_tx from
> there(?).
>
> This patch allowed em485_start/stop_tx to be called in my tests:
>
>
> [PATCH 1/1] serial: 8250: use THRE & __stop_tx also with DMA
>
> Currently, DMA complete handling in 8250 driver does not use THRE
> to detect true completion of the tx and also doesn't call __stop_tx.
> This leads to problems with em485 that needs to handle RTS timing.
>
> Instead of handling tx stop within 8250 dma code, enable THRE when
> tx data runs out and tweak serial8250_handle_irq to call
> __stop_tx when uart is using DMA.
>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> ---
> drivers/tty/serial/8250/8250_dma.c | 4 ++--
> drivers/tty/serial/8250/8250_port.c | 9 ++++++---
> 2 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/tty/serial/8250/8250_dma.c b/drivers/tty/serial/8250/8250_dma.c
> index 890fa7ddaa7f..e84db0abf365 100644
> --- a/drivers/tty/serial/8250/8250_dma.c
> +++ b/drivers/tty/serial/8250/8250_dma.c
> @@ -29,12 +29,13 @@ static void __dma_tx_complete(void *param)
> xmit->tail += dma->tx_size;
> xmit->tail &= UART_XMIT_SIZE - 1;
> p->port.icount.tx += dma->tx_size;
> + dma->tx_size = 0;
>
> if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
> uart_write_wakeup(&p->port);
>
> ret = serial8250_tx_dma(p);
> - if (ret)
> + if (ret || !dma->tx_size)
> serial8250_set_THRI(p);
>
> spin_unlock_irqrestore(&p->port.lock, flags);
> @@ -71,7 +72,6 @@ int serial8250_tx_dma(struct uart_8250_port *p)
>
> if (uart_tx_stopped(&p->port) || uart_circ_empty(xmit)) {
> /* We have been called from __dma_tx_complete() */
> - serial8250_rpm_put_tx(p);
> return 0;
> }
>
> diff --git a/drivers/tty/serial/8250/8250_port.c b/drivers/tty/serial/8250/8250_port.c
> index b3289ef117d1..72f144449ee1 100644
> --- a/drivers/tty/serial/8250/8250_port.c
> +++ b/drivers/tty/serial/8250/8250_port.c
> @@ -1960,9 +1960,12 @@ int serial8250_handle_irq(struct uart_port *port, unsigned int iir)
> status = serial8250_rx_chars(up, status);
> }
> serial8250_modem_status(up);
> - if ((!up->dma || up->dma->tx_err) && (status & UART_LSR_THRE) &&
> - (up->ier & UART_IER_THRI))
> - serial8250_tx_chars(up);
> + if ((status & UART_LSR_THRE) && (up->ier & UART_IER_THRI)) {
> + if (!up->dma || up->dma->tx_err)
> + serial8250_tx_chars(up);
> + else
> + __stop_tx(up);
> + }
>
> uart_unlock_and_check_sysrq_irqrestore(port, flags);
>
> --
> 2.35.1
^ permalink raw reply [flat|nested] 30+ messages in thread* Re: [PATCH v3 00/12] Add RS485 support to DW UART
2022-04-23 23:57 ` Vicente Bergas
@ 2022-04-25 11:16 ` Ilpo Järvinen
0 siblings, 0 replies; 30+ messages in thread
From: Ilpo Järvinen @ 2022-04-25 11:16 UTC (permalink / raw)
To: Vicente Bergas
Cc: Andy Shevchenko, giulio.benetti, Greg Kroah-Hartman,
heikki.krogerus, Heiko Stübner, jirislaby, johan, linux-api,
linux-serial, Lukas Wunner, Uwe Kleine-König
[-- Attachment #1: Type: text/plain, Size: 1672 bytes --]
On Sun, 24 Apr 2022, Vicente Bergas wrote:
> Hi Ilpo, thank you for your quick reply with a solution!
>
> On Fri, Apr 22, 2022 at 3:07 PM Ilpo Järvinen
> <ilpo.jarvinen@linux.intel.com> wrote:
> >
> > On Fri, 22 Apr 2022, Ilpo Järvinen wrote:
> >
> > > On Thu, 21 Apr 2022, Vicente Bergas wrote:
> > >
> > > > 1.- rs485_stop_tx is never called because there are no interrupts.
> > > > I worked around this by disabling DMA:
> > >
> > > I'll need to look into this.
> >
> > 8250 DMA tx complete path lacks calls to normal 8250 stop handling and
> > I think it probably also assumes too much from dmaengine's completion
> > callback. ...It also seems bit early to call serial8250_rpm_put_tx from
> > there(?).
> >
> > This patch allowed em485_start/stop_tx to be called in my tests:
> > [PATCH 1/1] serial: 8250: use THRE & __stop_tx also with DMA
>
> I confirm that this patch fixes the issue when DMA is enabled.
>
> I also confirm that your other patch
> > + stop_delay = p->port.frame_time + DIV_ROUND_UP(p->port.frame_time, 7);
> fixes the issue with RTS/DriverEnable deassertion time.
> I've tested it again at 19200e1 and now RTS is deasserted
> approximately at the same time as the end of the stop bit.
> Please, note the "e" for even parity bit, that extra bit after the
> data byte might have an impact on this timings.
Great, thanks again for testing.
I don't think that parity "e" makes the calculations incorrect as parity
bit should be taken into account in tty_get_frame_size(). My guess is it's
more about whether THRE might get asserted already during the stop bit or
only after the stop bit has been fully sent.
--
i.
^ permalink raw reply [flat|nested] 30+ messages in thread