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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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e6a46719a2
[ Upstream commit 1bd2aad57d ]
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>
Acked-by: Richard Genoud <richard.genoud@bootlin.com>
Link: https://lore.kernel.org/r/20250217-atomic_sleep_mctrl_serial_gpio-v3-1-59324b313eef@bootlin.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
177 lines
4.0 KiB
C
177 lines
4.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Helpers for controlling modem lines via GPIO
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*
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* Copyright (C) 2014 Paratronic S.A.
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*/
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#ifndef __SERIAL_MCTRL_GPIO__
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#define __SERIAL_MCTRL_GPIO__
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#include <linux/err.h>
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#include <linux/device.h>
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#include <linux/gpio/consumer.h>
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struct uart_port;
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enum mctrl_gpio_idx {
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UART_GPIO_CTS,
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UART_GPIO_DSR,
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UART_GPIO_DCD,
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UART_GPIO_RNG,
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UART_GPIO_RI = UART_GPIO_RNG,
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UART_GPIO_RTS,
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UART_GPIO_DTR,
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UART_GPIO_MAX,
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};
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/*
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* Opaque descriptor for modem lines controlled by GPIOs
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*/
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struct mctrl_gpios;
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#ifdef CONFIG_GPIOLIB
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/*
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* Set state of the modem control output lines via GPIOs.
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*/
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void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl);
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/*
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* Get state of the modem control input lines from GPIOs.
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* The mctrl flags are updated and returned.
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*/
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unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl);
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/*
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* Get state of the modem control output lines from GPIOs.
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* The mctrl flags are updated and returned.
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*/
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unsigned int
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mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl);
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/*
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* Returns the associated struct gpio_desc to the modem line gidx
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*/
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struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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enum mctrl_gpio_idx gidx);
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/*
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* Request and set direction of modem control line GPIOs and set up irq
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* handling.
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* devm_* functions are used, so there's no need to call mctrl_gpio_free().
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* Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
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* allocation error.
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*/
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struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx);
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/*
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* Request and set direction of modem control line GPIOs.
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* devm_* functions are used, so there's no need to call mctrl_gpio_free().
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* Returns a pointer to the allocated mctrl structure if ok, -ENOMEM on
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* allocation error.
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*/
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struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev,
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unsigned int idx);
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/*
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* Free the mctrl_gpios structure.
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* Normally, this function will not be called, as the GPIOs will
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* be disposed of by the resource management code.
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*/
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios);
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/*
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* Enable gpio interrupts to report status line changes.
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*/
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void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios);
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/*
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* Disable gpio interrupts to report status line changes, and block until
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* any corresponding IRQ is processed
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*/
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void mctrl_gpio_disable_ms_sync(struct mctrl_gpios *gpios);
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/*
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* Disable gpio interrupts to report status line changes, and return
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* immediately
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*/
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void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios);
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/*
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* Enable gpio wakeup interrupts to enable wake up source.
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*/
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void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios);
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/*
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* Disable gpio wakeup interrupts to enable wake up source.
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*/
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void mctrl_gpio_disable_irq_wake(struct mctrl_gpios *gpios);
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#else /* GPIOLIB */
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static inline
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void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
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{
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}
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static inline
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unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
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{
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return *mctrl;
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}
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static inline unsigned int
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mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
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{
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return *mctrl;
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}
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static inline
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struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
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enum mctrl_gpio_idx gidx)
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{
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return NULL;
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}
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static inline
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struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
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{
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return NULL;
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}
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static inline
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struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
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{
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return NULL;
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}
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static inline
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void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
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{
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}
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static inline void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
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{
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}
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static inline void mctrl_gpio_disable_ms_sync(struct mctrl_gpios *gpios)
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{
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}
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static inline void mctrl_gpio_disable_ms_no_sync(struct mctrl_gpios *gpios)
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{
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}
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static inline void mctrl_gpio_enable_irq_wake(struct mctrl_gpios *gpios)
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{
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}
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static inline void mctrl_gpio_disable_irq_wake(struct mctrl_gpios *gpios)
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{
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}
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#endif /* GPIOLIB */
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#endif
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