@@ -103,4 +103,4 @@ Some helpers are provided in order to set/get modem control lines via GPIO.
.. kernel-doc:: drivers/tty/serial/serial_mctrl_gpio.c
:identifiers: mctrl_gpio_init mctrl_gpio_free mctrl_gpio_to_gpiod
mctrl_gpio_set mctrl_gpio_get mctrl_gpio_enable_ms
- mctrl_gpio_disable_ms
+ mctrl_gpio_disable_ms_sync mctrl_gpio_disable_ms_no_sync
@@ -1680,7 +1680,7 @@ static void serial8250_disable_ms(struct uart_port *port)
if (up->bugs & UART_BUG_NOMSR)
return;
- mctrl_gpio_disable_ms(up->gpios);
+ mctrl_gpio_disable_ms_no_sync(up->gpios);
up->ier &= ~UART_IER_MSI;
serial_port_out(port, UART_IER, up->ier);
@@ -700,7 +700,7 @@ static void atmel_disable_ms(struct uart_port *port)
atmel_port->ms_irq_enabled = false;
- mctrl_gpio_disable_ms(atmel_port->gpios);
+ mctrl_gpio_disable_ms_no_sync(atmel_port->gpios);
if (!mctrl_gpio_to_gpiod(atmel_port->gpios, UART_GPIO_CTS))
idr |= ATMEL_US_CTSIC;
@@ -1608,7 +1608,7 @@ static void imx_uart_shutdown(struct uart_port *port)
imx_uart_dma_exit(sport);
}
- mctrl_gpio_disable_ms(sport->gpios);
+ mctrl_gpio_disable_ms_sync(sport->gpios);
uart_port_lock_irqsave(&sport->port, &flags);
ucr2 = imx_uart_readl(sport, UCR2);
@@ -322,11 +322,7 @@ void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
}
EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
-/**
- * mctrl_gpio_disable_ms - disable irqs and handling of changes to the ms lines
- * @gpios: gpios to disable
- */
-void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
+static void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios, bool sync)
{
enum mctrl_gpio_idx i;
@@ -342,10 +338,34 @@ void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
if (!gpios->irq[i])
continue;
- disable_irq(gpios->irq[i]);
+ if (sync)
+ disable_irq(gpios->irq[i]);
+ else
+ disable_irq_nosync(gpios->irq[i]);
}
}
-EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
+
+/**
+ * mctrl_gpio_disable_ms_sync - disable irqs and handling of changes to the ms
+ * lines, and wait for any pending IRQ to be processed
+ * @gpios: gpios to disable
+ */
+void mctrl_gpio_disable_ms_sync(struct mctrl_gpios *gpios)
+{
+ mctrl_gpio_disable_ms(gpios, true);
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms_sync);
+
+/**
+ * mctrl_gpio_disable_ms_no_sync - disable irqs and handling of changes to the
+ * ms lines, and return immediately
+ * @gpios: gpios to disable
+ */
+void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios)
+{
+ mctrl_gpio_disable_ms(gpios, false);
+}
+EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms_no_sync);
void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios)
{
@@ -87,9 +87,16 @@ void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
/*
- * Disable gpio interrupts to report status line changes.
+ * Disable gpio interrupts to report status line changes, and block until
+ * any corresponding IRQ is processed
*/
-void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios);
+void mctrl_gpio_disable_ms_sync(struct mctrl_gpios *gpios);
+
+/*
+ * Disable gpio interrupts to report status line changes, and return
+ * immediately
+ */
+void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios);
/*
* Enable gpio wakeup interrupts to enable wake up source.
@@ -148,7 +155,11 @@ static inline void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
{
}
-static inline void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
+static inline void mctrl_gpio_disable_ms_sync(struct mctrl_gpios *gpios)
+{
+}
+
+static inline void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios)
{
}
@@ -2298,7 +2298,7 @@ static void sci_shutdown(struct uart_port *port)
dev_dbg(port->dev, "%s(%d)\n", __func__, port->line);
s->autorts = false;
- mctrl_gpio_disable_ms(to_sci_port(port)->gpios);
+ mctrl_gpio_disable_ms_sync(to_sci_port(port)->gpios);
uart_port_lock_irqsave(port, &flags);
sci_stop_rx(port);
@@ -944,7 +944,7 @@ static void stm32_usart_enable_ms(struct uart_port *port)
static void stm32_usart_disable_ms(struct uart_port *port)
{
- mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
+ mctrl_gpio_disable_ms_sync(to_stm32_port(port)->gpios);
}
/* Transmit stop */
The following splat has been observed on a SAMA5D27 platform using atmel_serial: BUG: sleeping function called from invalid context at kernel/irq/manage.c:738 in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 27, name: kworker/u5:0 preempt_count: 1, expected: 0 INFO: lockdep is turned off. irq event stamp: 0 hardirqs last enabled at (0): [<00000000>] 0x0 hardirqs last disabled at (0): [<c01588f0>] copy_process+0x1c4c/0x7bec softirqs last enabled at (0): [<c0158944>] copy_process+0x1ca0/0x7bec softirqs last disabled at (0): [<00000000>] 0x0 CPU: 0 UID: 0 PID: 27 Comm: kworker/u5:0 Not tainted 6.13.0-rc7+ #74 Hardware name: Atmel SAMA5 Workqueue: hci0 hci_power_on [bluetooth] Call trace: unwind_backtrace from show_stack+0x18/0x1c show_stack from dump_stack_lvl+0x44/0x70 dump_stack_lvl from __might_resched+0x38c/0x598 __might_resched from disable_irq+0x1c/0x48 disable_irq from mctrl_gpio_disable_ms+0x74/0xc0 mctrl_gpio_disable_ms from atmel_disable_ms.part.0+0x80/0x1f4 atmel_disable_ms.part.0 from atmel_set_termios+0x764/0x11e8 atmel_set_termios from uart_change_line_settings+0x15c/0x994 uart_change_line_settings from uart_set_termios+0x2b0/0x668 uart_set_termios from tty_set_termios+0x600/0x8ec tty_set_termios from ttyport_set_flow_control+0x188/0x1e0 ttyport_set_flow_control from wilc_setup+0xd0/0x524 [hci_wilc] wilc_setup [hci_wilc] from hci_dev_open_sync+0x330/0x203c [bluetooth] hci_dev_open_sync [bluetooth] from hci_dev_do_open+0x40/0xb0 [bluetooth] hci_dev_do_open [bluetooth] from hci_power_on+0x12c/0x664 [bluetooth] hci_power_on [bluetooth] from process_one_work+0x998/0x1a38 process_one_work from worker_thread+0x6e0/0xfb4 worker_thread from kthread+0x3d4/0x484 kthread from ret_from_fork+0x14/0x28 This warning is emitted when trying to toggle, at the highest level, some flow control (with serdev_device_set_flow_control) in a device driver. At the lowest level, the atmel_serial driver is using serial_mctrl_gpio lib to enable/disable the corresponding IRQs accordingly. The warning emitted by CONFIG_DEBUG_ATOMIC_SLEEP is due to disable_irq (called in mctrl_gpio_disable_ms) being possibly called in some atomic context (some tty drivers perform modem lines configuration in regions protected by port lock). Split mctrl_gpio_disable_ms into two differents APIs, a non-blocking one and a blocking one. Replace mctrl_gpio_disable_ms calls with the relevant version depending on whether the call is protected by some port lock. Suggested-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Alexis Lothoré <alexis.lothore@bootlin.com> --- Changes in v3: - Fix commit message - Link to v2: https://lore.kernel.org/r/20250214-atomic_sleep_mctrl_serial_gpio-v2-1-1e60c732fd90@bootlin.com Changes in v2: - create dedicated APIs instead of using custom flag - Link to v1: https://lore.kernel.org/r/20250213-atomic_sleep_mctrl_serial_gpio-v1-1-201ee6a148ad@bootlin.com --- Documentation/driver-api/serial/driver.rst | 2 +- drivers/tty/serial/8250/8250_port.c | 2 +- drivers/tty/serial/atmel_serial.c | 2 +- drivers/tty/serial/imx.c | 2 +- drivers/tty/serial/serial_mctrl_gpio.c | 34 ++++++++++++++++++++++++------ drivers/tty/serial/serial_mctrl_gpio.h | 17 ++++++++++++--- drivers/tty/serial/sh-sci.c | 2 +- drivers/tty/serial/stm32-usart.c | 2 +- 8 files changed, 47 insertions(+), 16 deletions(-) --- base-commit: 2014c95afecee3e76ca4a56956a936e23283f05b change-id: 20250213-atomic_sleep_mctrl_serial_gpio-885f6feb585b Best regards,