[PATCH AUTOSEL 6.1 13/60] tty: serial: fsl_lpuart: disable the CTS when send break signal

[PATCH AUTOSEL 6.1 13/60] tty: serial: fsl_lpuart: disable the CTS when send break signal

[Sasha Levin]

From: Sherry Sun <sherry.sun@nxp.com>

[ Upstream commit c4c81db5cf8bc53d6160c3abf26d382c841aa434 ]

LPUART IP has a bug that it treats the CTS as higher priority than the
break signal, which cause the break signal sending through UARTCTRL_SBK
may impacted by the CTS input if the HW flow control is enabled.

Add this workaround patch to fix the IP bug, we can disable CTS before
asserting SBK to avoid any interference from CTS, and re-enable it when
break off.

Such as for the bluetooth chip power save feature, host can let the BT
chip get into sleep state by sending a UART break signal, and wake it up
by turning off the UART break. If the BT chip enters the sleep mode
successfully, it will pull up the CTS line, if the BT chip is woken up,
it will pull down the CTS line. If without this workaround patch, the
UART TX pin cannot send the break signal successfully as it affected by
the BT CTS pin. After adding this patch, the BT power save feature can
work well.

Signed-off-by: Sherry Sun <sherry.sun@nxp.com>
Link: https://lore.kernel.org/r/20221214031137.28815-2-sherry.sun@nxp.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/fsl_lpuart.c | 24 ++++++++++++++++++++++--
 1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
index 888e01fbd9c5f..8af4f6bb66509 100644
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -1468,12 +1468,32 @@ static void lpuart_break_ctl(struct uart_port *port, int break_state)
 
 static void lpuart32_break_ctl(struct uart_port *port, int break_state)
 {
-	unsigned long temp;
+	unsigned long temp, modem;
+	struct tty_struct *tty;
+	unsigned int cflag = 0;
+
+	tty = tty_port_tty_get(&port->state->port);
+	if (tty) {
+		cflag = tty->termios.c_cflag;
+		tty_kref_put(tty);
+	}
 
 	temp = lpuart32_read(port, UARTCTRL) & ~UARTCTRL_SBK;
+	modem = lpuart32_read(port, UARTMODIR);
 
-	if (break_state != 0)
+	if (break_state != 0) {
 		temp |= UARTCTRL_SBK;
+		/*
+		 * LPUART CTS has higher priority than SBK, need to disable CTS before
+		 * asserting SBK to avoid any interference if flow control is enabled.
+		 */
+		if (cflag & CRTSCTS && modem & UARTMODIR_TXCTSE)
+			lpuart32_write(port, modem & ~UARTMODIR_TXCTSE, UARTMODIR);
+	} else {
+		/* Re-enable the CTS when break off. */
+		if (cflag & CRTSCTS && !(modem & UARTMODIR_TXCTSE))
+			lpuart32_write(port, modem | UARTMODIR_TXCTSE, UARTMODIR);
+	}
 
 	lpuart32_write(port, temp, UARTCTRL);
 }
-- 
2.39.2

[PATCH AUTOSEL 6.1 14/60] serial: sc16is7xx: setup GPIO controller later in probe

[Sasha Levin]

From: Isaac True <isaac.true@canonical.com>

[ Upstream commit c8f71b49ee4d28930c4a6798d1969fa91dc4ef3e ]

The GPIO controller component of the sc16is7xx driver is setup too
early, which can result in a race condition where another device tries
to utilise the GPIO lines before the sc16is7xx device has finished
initialising.

This issue manifests itself as an Oops when the GPIO lines are configured:

    Unable to handle kernel read from unreadable memory at virtual address
    ...
    pc : sc16is7xx_gpio_direction_output+0x68/0x108 [sc16is7xx]
    lr : sc16is7xx_gpio_direction_output+0x4c/0x108 [sc16is7xx]
    ...
    Call trace:
    sc16is7xx_gpio_direction_output+0x68/0x108 [sc16is7xx]
    gpiod_direction_output_raw_commit+0x64/0x318
    gpiod_direction_output+0xb0/0x170
    create_gpio_led+0xec/0x198
    gpio_led_probe+0x16c/0x4f0
    platform_drv_probe+0x5c/0xb0
    really_probe+0xe8/0x448
    driver_probe_device+0xe8/0x138
    __device_attach_driver+0x94/0x118
    bus_for_each_drv+0x8c/0xe0
    __device_attach+0x100/0x1b8
    device_initial_probe+0x28/0x38
    bus_probe_device+0xa4/0xb0
    deferred_probe_work_func+0x90/0xe0
    process_one_work+0x1c4/0x480
    worker_thread+0x54/0x430
    kthread+0x138/0x150
    ret_from_fork+0x10/0x1c

This patch moves the setup of the GPIO controller functions to later in the
probe function, ensuring the sc16is7xx device has already finished
initialising by the time other devices try to make use of the GPIO lines.
The error handling has also been reordered to reflect the new
initialisation order.

Co-developed-by: Wen-chien Jesse Sung <jesse.sung@canonical.com>
Signed-off-by: Wen-chien Jesse Sung <jesse.sung@canonical.com>
Signed-off-by: Isaac True <isaac.true@canonical.com>
Link: https://lore.kernel.org/r/20221130105529.698385-1-isaac.true@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/sc16is7xx.c | 51 +++++++++++++++++-----------------
 1 file changed, 26 insertions(+), 25 deletions(-)

diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index 524921360ca78..93cf5f7888172 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1426,25 +1426,6 @@ static int sc16is7xx_probe(struct device *dev,
 	}
 	sched_set_fifo(s->kworker_task);
 
-#ifdef CONFIG_GPIOLIB
-	if (devtype->nr_gpio) {
-		/* Setup GPIO cotroller */
-		s->gpio.owner		 = THIS_MODULE;
-		s->gpio.parent		 = dev;
-		s->gpio.label		 = dev_name(dev);
-		s->gpio.direction_input	 = sc16is7xx_gpio_direction_input;
-		s->gpio.get		 = sc16is7xx_gpio_get;
-		s->gpio.direction_output = sc16is7xx_gpio_direction_output;
-		s->gpio.set		 = sc16is7xx_gpio_set;
-		s->gpio.base		 = -1;
-		s->gpio.ngpio		 = devtype->nr_gpio;
-		s->gpio.can_sleep	 = 1;
-		ret = gpiochip_add_data(&s->gpio, s);
-		if (ret)
-			goto out_thread;
-	}
-#endif
-
 	/* reset device, purging any pending irq / data */
 	regmap_write(s->regmap, SC16IS7XX_IOCONTROL_REG << SC16IS7XX_REG_SHIFT,
 			SC16IS7XX_IOCONTROL_SRESET_BIT);
@@ -1521,6 +1502,25 @@ static int sc16is7xx_probe(struct device *dev,
 				s->p[u].irda_mode = true;
 	}
 
+#ifdef CONFIG_GPIOLIB
+	if (devtype->nr_gpio) {
+		/* Setup GPIO cotroller */
+		s->gpio.owner		 = THIS_MODULE;
+		s->gpio.parent		 = dev;
+		s->gpio.label		 = dev_name(dev);
+		s->gpio.direction_input	 = sc16is7xx_gpio_direction_input;
+		s->gpio.get		 = sc16is7xx_gpio_get;
+		s->gpio.direction_output = sc16is7xx_gpio_direction_output;
+		s->gpio.set		 = sc16is7xx_gpio_set;
+		s->gpio.base		 = -1;
+		s->gpio.ngpio		 = devtype->nr_gpio;
+		s->gpio.can_sleep	 = 1;
+		ret = gpiochip_add_data(&s->gpio, s);
+		if (ret)
+			goto out_thread;
+	}
+#endif
+
 	/*
 	 * Setup interrupt. We first try to acquire the IRQ line as level IRQ.
 	 * If that succeeds, we can allow sharing the interrupt as well.
@@ -1540,18 +1540,19 @@ static int sc16is7xx_probe(struct device *dev,
 	if (!ret)
 		return 0;
 
-out_ports:
-	for (i--; i >= 0; i--) {
-		uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
-		clear_bit(s->p[i].port.line, &sc16is7xx_lines);
-	}
-
 #ifdef CONFIG_GPIOLIB
 	if (devtype->nr_gpio)
 		gpiochip_remove(&s->gpio);
 
 out_thread:
 #endif
+
+out_ports:
+	for (i--; i >= 0; i--) {
+		uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
+		clear_bit(s->p[i].port.line, &sc16is7xx_lines);
+	}
+
 	kthread_stop(s->kworker_task);
 
 out_clk:
-- 
2.39.2

[PATCH AUTOSEL 6.1 46/60] tty: pcn_uart: fix memory leak with using debugfs_lookup()

[Sasha Levin]

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

[ Upstream commit 04a189c720aa2b6091442113ce9b9bc93552dff8 ]

When calling debugfs_lookup() the result must have dput() called on it,
otherwise the memory will leak over time.  To make things simpler, just
call debugfs_lookup_and_remove() instead which handles all of the logic
at once.

Cc: Jiri Slaby <jirislaby@kernel.org>
Link: https://lore.kernel.org/r/20230202141221.2293012-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/tty/serial/pch_uart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/pch_uart.c b/drivers/tty/serial/pch_uart.c
index 83f35b7b0897c..abff1c6470f6a 100644
--- a/drivers/tty/serial/pch_uart.c
+++ b/drivers/tty/serial/pch_uart.c
@@ -1779,7 +1779,7 @@ static void pch_uart_exit_port(struct eg20t_port *priv)
 	char name[32];
 
 	snprintf(name, sizeof(name), "uart%d_regs", priv->port.line);
-	debugfs_remove(debugfs_lookup(name, NULL));
+	debugfs_lookup_and_remove(name, NULL);
 	uart_remove_one_port(&pch_uart_driver, &priv->port);
 	free_page((unsigned long)priv->rxbuf.buf);
 }
-- 
2.39.2