--- /dev/null
+From 0ed12afa5655512ee418047fb3546d229df20aa1 Mon Sep 17 00:00:00 2001
+From: Lino Sanfilippo <LinoSanfilippo@gmx.de>
+Date: Sun, 10 Apr 2022 12:46:34 +0200
+Subject: serial: core: move RS485 configuration tasks from drivers into core
+
+From: Lino Sanfilippo <LinoSanfilippo@gmx.de>
+
+commit 0ed12afa5655512ee418047fb3546d229df20aa1 upstream.
+
+Several drivers that support setting the RS485 configuration via userspace
+implement one or more of the following tasks:
+
+- in case of an invalid RTS configuration (both RTS after send and RTS on
+ send set or both unset) fall back to enable RTS on send and disable RTS
+ after send
+
+- nullify the padding field of the returned serial_rs485 struct
+
+- copy the configuration into the uart port struct
+
+- limit RTS delays to 100 ms
+
+Move these tasks into the serial core to make them generic and to provide
+a consistent behaviour among all drivers.
+
+Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
+Link: https://lore.kernel.org/r/20220410104642.32195-2-LinoSanfilippo@gmx.de
+Signed-off-by: Daisuke Mizobuchi <mizo@atmark-techno.com>
+Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/serial_core.c | 33 +++++++++++++++++++++++++++++++++
+ 1 file changed, 33 insertions(+)
+
+--- a/drivers/tty/serial/serial_core.c
++++ b/drivers/tty/serial/serial_core.c
+@@ -42,6 +42,11 @@ static struct lock_class_key port_lock_k
+
+ #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
+
++/*
++ * Max time with active RTS before/after data is sent.
++ */
++#define RS485_MAX_RTS_DELAY 100 /* msecs */
++
+ static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
+ struct ktermios *old_termios);
+ static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
+@@ -1299,8 +1304,36 @@ static int uart_set_rs485_config(struct
+ if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
+ return -EFAULT;
+
++ /* pick sane settings if the user hasn't */
++ if (!(rs485.flags & SER_RS485_RTS_ON_SEND) ==
++ !(rs485.flags & SER_RS485_RTS_AFTER_SEND)) {
++ dev_warn_ratelimited(port->dev,
++ "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
++ port->name, port->line);
++ rs485.flags |= SER_RS485_RTS_ON_SEND;
++ rs485.flags &= ~SER_RS485_RTS_AFTER_SEND;
++ }
++
++ if (rs485.delay_rts_before_send > RS485_MAX_RTS_DELAY) {
++ rs485.delay_rts_before_send = RS485_MAX_RTS_DELAY;
++ dev_warn_ratelimited(port->dev,
++ "%s (%d): RTS delay before sending clamped to %u ms\n",
++ port->name, port->line, rs485.delay_rts_before_send);
++ }
++
++ if (rs485.delay_rts_after_send > RS485_MAX_RTS_DELAY) {
++ rs485.delay_rts_after_send = RS485_MAX_RTS_DELAY;
++ dev_warn_ratelimited(port->dev,
++ "%s (%d): RTS delay after sending clamped to %u ms\n",
++ port->name, port->line, rs485.delay_rts_after_send);
++ }
++ /* Return clean padding area to userspace */
++ memset(rs485.padding, 0, sizeof(rs485.padding));
++
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->rs485_config(port, &rs485);
++ if (!ret)
++ port->rs485 = rs485;
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
--- /dev/null
+From 7c7f9bc986e698873b489c371a08f206979d06b7 Mon Sep 17 00:00:00 2001
+From: Lukas Wunner <lukas@wunner.de>
+Date: Thu, 22 Sep 2022 18:27:33 +0200
+Subject: serial: Deassert Transmit Enable on probe in driver-specific way
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+From: Lukas Wunner <lukas@wunner.de>
+
+commit 7c7f9bc986e698873b489c371a08f206979d06b7 upstream.
+
+When a UART port is newly registered, uart_configure_port() seeks to
+deassert RS485 Transmit Enable by setting the RTS bit in port->mctrl.
+However a number of UART drivers interpret a set RTS bit as *assertion*
+instead of deassertion: Affected drivers include those using
+serial8250_em485_config() (except 8250_bcm2835aux.c) and some using
+mctrl_gpio (e.g. imx.c).
+
+Since the interpretation of the RTS bit is driver-specific, it is not
+suitable as a means to centrally deassert Transmit Enable in the serial
+core. Instead, the serial core must call on drivers to deassert it in
+their driver-specific way. One way to achieve that is to call
+->rs485_config(). It implicitly deasserts Transmit Enable.
+
+So amend uart_configure_port() and uart_resume_port() to invoke
+uart_rs485_config(). That allows removing calls to uart_rs485_config()
+from drivers' ->probe() hooks and declaring the function static.
+
+Skip any invocation of ->set_mctrl() if RS485 is enabled. RS485 has no
+hardware flow control, so the modem control lines are irrelevant and
+need not be touched. When leaving RS485 mode, reset the modem control
+lines to the state stored in port->mctrl. That way, UARTs which are
+muxed between RS485 and RS232 transceivers drive the lines correctly
+when switched to RS232. (serial8250_do_startup() historically raises
+the OUT1 modem signal because otherwise interrupts are not signaled on
+ancient PC UARTs, but I believe that no longer applies to modern,
+RS485-capable UARTs and is thus safe to be skipped.)
+
+imx.c modifies port->mctrl whenever Transmit Enable is asserted and
+deasserted. Stop it from doing that so port->mctrl reflects the RS232
+line state.
+
+8250_omap.c deasserts Transmit Enable on ->runtime_resume() by calling
+->set_mctrl(). Because that is now a no-op in RS485 mode, amend the
+function to call serial8250_em485_stop_tx().
+
+fsl_lpuart.c retrieves and applies the RS485 device tree properties
+after registering the UART port. Because applying now happens on
+registration in uart_configure_port(), move retrieval of the properties
+ahead of uart_add_one_port().
+
+Link: https://lore.kernel.org/all/20220329085050.311408-1-matthias.schiffer@ew.tq-group.com/
+Link: https://lore.kernel.org/all/8f538a8903795f22f9acc94a9a31b03c9c4ccacb.camel@ginzinger.com/
+Fixes: d3b3404df318 ("serial: Fix incorrect rs485 polarity on uart open")
+Cc: stable@vger.kernel.org # v4.14+
+Reported-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
+Reported-by: Roosen Henri <Henri.Roosen@ginzinger.com>
+Tested-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
+Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
+Signed-off-by: Lukas Wunner <lukas@wunner.de>
+Link: https://lore.kernel.org/r/2de36eba3fbe11278d5002e4e501afe0ceaca039.1663863805.git.lukas@wunner.de
+Signed-off-by: Daisuke Mizobuchi <mizo@atmark-techno.com>
+Signed-off-by: Dominique Martinet <dominique.martinet@atmark-techno.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ drivers/tty/serial/8250/8250_omap.c | 3 +++
+ drivers/tty/serial/8250/8250_pci.c | 9 +--------
+ drivers/tty/serial/8250/8250_port.c | 12 +++++++-----
+ drivers/tty/serial/fsl_lpuart.c | 8 +++-----
+ drivers/tty/serial/imx.c | 8 ++------
+ drivers/tty/serial/serial_core.c | 30 +++++++++++++++++-------------
+ 6 files changed, 33 insertions(+), 37 deletions(-)
+
+--- a/drivers/tty/serial/8250/8250_omap.c
++++ b/drivers/tty/serial/8250/8250_omap.c
+@@ -342,6 +342,9 @@ static void omap8250_restore_regs(struct
+ omap8250_update_mdr1(up, priv);
+
+ up->port.ops->set_mctrl(&up->port, up->port.mctrl);
++
++ if (up->port.rs485.flags & SER_RS485_ENABLED)
++ serial8250_em485_stop_tx(up);
+ }
+
+ /*
+--- a/drivers/tty/serial/8250/8250_pci.c
++++ b/drivers/tty/serial/8250/8250_pci.c
+@@ -1739,7 +1739,6 @@ static int pci_fintek_init(struct pci_de
+ resource_size_t bar_data[3];
+ u8 config_base;
+ struct serial_private *priv = pci_get_drvdata(dev);
+- struct uart_8250_port *port;
+
+ if (!(pci_resource_flags(dev, 5) & IORESOURCE_IO) ||
+ !(pci_resource_flags(dev, 4) & IORESOURCE_IO) ||
+@@ -1786,13 +1785,7 @@ static int pci_fintek_init(struct pci_de
+
+ pci_write_config_byte(dev, config_base + 0x06, dev->irq);
+
+- if (priv) {
+- /* re-apply RS232/485 mode when
+- * pciserial_resume_ports()
+- */
+- port = serial8250_get_port(priv->line[i]);
+- pci_fintek_rs485_config(&port->port, NULL);
+- } else {
++ if (!priv) {
+ /* First init without port data
+ * force init to RS232 Mode
+ */
+--- a/drivers/tty/serial/8250/8250_port.c
++++ b/drivers/tty/serial/8250/8250_port.c
+@@ -600,7 +600,7 @@ EXPORT_SYMBOL_GPL(serial8250_rpm_put);
+ static int serial8250_em485_init(struct uart_8250_port *p)
+ {
+ if (p->em485)
+- return 0;
++ goto deassert_rts;
+
+ p->em485 = kmalloc(sizeof(struct uart_8250_em485), GFP_ATOMIC);
+ if (!p->em485)
+@@ -616,7 +616,9 @@ static int serial8250_em485_init(struct
+ p->em485->active_timer = NULL;
+ p->em485->tx_stopped = true;
+
+- p->rs485_stop_tx(p);
++deassert_rts:
++ if (p->em485->tx_stopped)
++ p->rs485_stop_tx(p);
+
+ return 0;
+ }
+@@ -2034,6 +2036,9 @@ EXPORT_SYMBOL_GPL(serial8250_do_set_mctr
+
+ static void serial8250_set_mctrl(struct uart_port *port, unsigned int mctrl)
+ {
++ if (port->rs485.flags & SER_RS485_ENABLED)
++ return;
++
+ if (port->set_mctrl)
+ port->set_mctrl(port, mctrl);
+ else
+@@ -3191,9 +3196,6 @@ static void serial8250_config_port(struc
+ if (flags & UART_CONFIG_TYPE)
+ autoconfig(up);
+
+- if (port->rs485.flags & SER_RS485_ENABLED)
+- port->rs485_config(port, &port->rs485);
+-
+ /* if access method is AU, it is a 16550 with a quirk */
+ if (port->type == PORT_16550A && port->iotype == UPIO_AU)
+ up->bugs |= UART_BUG_NOMSR;
+--- a/drivers/tty/serial/fsl_lpuart.c
++++ b/drivers/tty/serial/fsl_lpuart.c
+@@ -2733,10 +2733,6 @@ static int lpuart_probe(struct platform_
+ if (ret)
+ goto failed_reset;
+
+- ret = uart_add_one_port(&lpuart_reg, &sport->port);
+- if (ret)
+- goto failed_attach_port;
+-
+ ret = uart_get_rs485_mode(&sport->port);
+ if (ret)
+ goto failed_get_rs485;
+@@ -2748,7 +2744,9 @@ static int lpuart_probe(struct platform_
+ sport->port.rs485.delay_rts_after_send)
+ dev_err(&pdev->dev, "driver doesn't support RTS delays\n");
+
+- sport->port.rs485_config(&sport->port, &sport->port.rs485);
++ ret = uart_add_one_port(&lpuart_reg, &sport->port);
++ if (ret)
++ goto failed_attach_port;
+
+ ret = devm_request_irq(&pdev->dev, sport->port.irq, handler, 0,
+ DRIVER_NAME, sport);
+--- a/drivers/tty/serial/imx.c
++++ b/drivers/tty/serial/imx.c
+@@ -380,8 +380,7 @@ static void imx_uart_rts_active(struct i
+ {
+ *ucr2 &= ~(UCR2_CTSC | UCR2_CTS);
+
+- sport->port.mctrl |= TIOCM_RTS;
+- mctrl_gpio_set(sport->gpios, sport->port.mctrl);
++ mctrl_gpio_set(sport->gpios, sport->port.mctrl | TIOCM_RTS);
+ }
+
+ /* called with port.lock taken and irqs caller dependent */
+@@ -390,8 +389,7 @@ static void imx_uart_rts_inactive(struct
+ *ucr2 &= ~UCR2_CTSC;
+ *ucr2 |= UCR2_CTS;
+
+- sport->port.mctrl &= ~TIOCM_RTS;
+- mctrl_gpio_set(sport->gpios, sport->port.mctrl);
++ mctrl_gpio_set(sport->gpios, sport->port.mctrl & ~TIOCM_RTS);
+ }
+
+ static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec)
+@@ -2318,8 +2316,6 @@ static int imx_uart_probe(struct platfor
+ dev_err(&pdev->dev,
+ "low-active RTS not possible when receiver is off, enabling receiver\n");
+
+- imx_uart_rs485_config(&sport->port, &sport->port.rs485);
+-
+ /* Disable interrupts before requesting them */
+ ucr1 = imx_uart_readl(sport, UCR1);
+ ucr1 &= ~(UCR1_ADEN | UCR1_TRDYEN | UCR1_IDEN | UCR1_RRDYEN | UCR1_RTSDEN);
+--- a/drivers/tty/serial/serial_core.c
++++ b/drivers/tty/serial/serial_core.c
+@@ -149,15 +149,10 @@ uart_update_mctrl(struct uart_port *port
+ unsigned long flags;
+ unsigned int old;
+
+- if (port->rs485.flags & SER_RS485_ENABLED) {
+- set &= ~TIOCM_RTS;
+- clear &= ~TIOCM_RTS;
+- }
+-
+ spin_lock_irqsave(&port->lock, flags);
+ old = port->mctrl;
+ port->mctrl = (old & ~clear) | set;
+- if (old != port->mctrl)
++ if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
+ port->ops->set_mctrl(port, port->mctrl);
+ spin_unlock_irqrestore(&port->lock, flags);
+ }
+@@ -1332,8 +1327,13 @@ static int uart_set_rs485_config(struct
+
+ spin_lock_irqsave(&port->lock, flags);
+ ret = port->rs485_config(port, &rs485);
+- if (!ret)
++ if (!ret) {
+ port->rs485 = rs485;
++
++ /* Reset RTS and other mctrl lines when disabling RS485 */
++ if (!(rs485.flags & SER_RS485_ENABLED))
++ port->ops->set_mctrl(port, port->mctrl);
++ }
+ spin_unlock_irqrestore(&port->lock, flags);
+ if (ret)
+ return ret;
+@@ -2306,7 +2306,8 @@ int uart_resume_port(struct uart_driver
+
+ uart_change_pm(state, UART_PM_STATE_ON);
+ spin_lock_irq(&uport->lock);
+- ops->set_mctrl(uport, 0);
++ if (!(uport->rs485.flags & SER_RS485_ENABLED))
++ ops->set_mctrl(uport, 0);
+ spin_unlock_irq(&uport->lock);
+ if (console_suspend_enabled || !uart_console(uport)) {
+ /* Protected by port mutex for now */
+@@ -2317,7 +2318,10 @@ int uart_resume_port(struct uart_driver
+ if (tty)
+ uart_change_speed(tty, state, NULL);
+ spin_lock_irq(&uport->lock);
+- ops->set_mctrl(uport, uport->mctrl);
++ if (!(uport->rs485.flags & SER_RS485_ENABLED))
++ ops->set_mctrl(uport, uport->mctrl);
++ else
++ uport->rs485_config(uport, &uport->rs485);
+ ops->start_tx(uport);
+ spin_unlock_irq(&uport->lock);
+ tty_port_set_initialized(port, 1);
+@@ -2423,10 +2427,10 @@ uart_configure_port(struct uart_driver *
+ */
+ spin_lock_irqsave(&port->lock, flags);
+ port->mctrl &= TIOCM_DTR;
+- if (port->rs485.flags & SER_RS485_ENABLED &&
+- !(port->rs485.flags & SER_RS485_RTS_AFTER_SEND))
+- port->mctrl |= TIOCM_RTS;
+- port->ops->set_mctrl(port, port->mctrl);
++ if (!(port->rs485.flags & SER_RS485_ENABLED))
++ port->ops->set_mctrl(port, port->mctrl);
++ else
++ port->rs485_config(port, &port->rs485);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ /*
projects / thirdparty / kernel / stable-queue.git / commitdiff
