linux-yocto/Documentation/driver-api
Alexis Lothoré 68435c1fa3 serial: mctrl_gpio: split disable_ms into sync and no_sync APIs
[ Upstream commit 1bd2aad57da95f7f2d2bb52f7ad15c0f4993a685 ]

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>
2025-06-04 14:40:13 +02:00
..
80211 docs: net: 80211: reduce docs build time 2020-10-08 10:41:49 +02:00
acpi Documentation: ACPI: fix error script name 2021-06-17 13:21:48 -06:00
backlight
cxl Documentation: cxl: remove dangling kernel-doc reference 2022-08-05 08:41:02 -07:00
dmaengine dmaengine: remove DMA_MEMCPY_SG once again 2022-06-27 12:01:40 +05:30
driver-model Documentation: devres: add missing I2C helper 2022-11-02 21:16:38 +01:00
early-userspace Documentation: Fix intiramfs script name 2021-07-18 23:48:14 +09:00
firmware Driver core / kernfs changes for 6.0-rc1 2022-08-04 11:31:20 -07:00
fpga fpga: manager: add owner module and take its refcount 2024-12-14 19:53:12 +01:00
gpio This was a moderately busy cycle for documentation, but nothing all that 2022-08-02 19:24:24 -07:00
hte tegra194-hte.rst: fix reference to its binding 2022-07-07 13:10:00 -06:00
i3c docs: driver-api: i3c: Replace HTTP links with HTTPS ones 2020-07-13 09:32:36 -06:00
iio docs: iio: mark "repeat" sysfs attribute as optional 2021-03-11 20:47:08 +00:00
md
media media: mc: entity: Rewrite media_pipeline_start() 2022-09-24 09:19:42 +02:00
mei docs updates for v5.10-rc1 2020-10-16 15:02:21 -07:00
memory-devices Replace HTTP links with HTTPS ones: Documentation/driver-api 2020-06-26 11:09:04 -06:00
mmc docs: mmc: update maintainer name and URL 2021-10-28 11:54:54 +02:00
mtd Documentation / MTD: Rename the intel-spi driver 2022-02-14 12:53:10 +00:00
nfc nfc: constify nfc_llc_ops 2021-07-25 09:21:21 +01:00
nvdimm nvdimm/blk: Fix title level 2022-03-23 17:52:33 -07:00
pci PCI/P2PDMA: Remove reference to pci_p2pdma_map_sg() 2024-01-25 15:27:44 -08:00
phy
pldmfw Add pldmfw library for PLDM firmware update 2020-07-28 17:07:06 -07:00
pm docs: devices.rst: better reference documentation docs 2021-06-17 13:24:36 -06:00
rapidio Replace HTTP links with HTTPS ones: Documentation/driver-api 2020-06-26 11:09:04 -06:00
serial serial: mctrl_gpio: split disable_ms into sync and no_sync APIs 2025-06-04 14:40:13 +02:00
soundwire docs: soundwire: fix some identation at stream.rst 2020-09-10 10:49:29 -06:00
surface_aggregator platform/surface: aggregator: Allow notifiers to avoid communication on unregistering 2022-06-13 17:25:07 +02:00
thermal docs: driver-api/thermal/intel_dptf: Use copyright symbol 2022-04-05 09:46:06 -06:00
tty Documentation: tty: n_gsm, use power of ReST 2022-04-14 18:24:24 +02:00
usb Docs: usb: update writesize, copy_from_user, usb_fill_bulk_urb, usb_submit_urb 2021-11-17 14:54:58 +01:00
xilinx firmware: xilinx: Remove zynqmp_pm_get_eemi_ops() in IS_REACHABLE(CONFIG_ZYNQMP_FIRMWARE) 2021-03-01 12:52:07 +01:00
aperture.rst drm: Implement DRM aperture helpers under video/ 2022-06-27 11:07:55 +02:00
auxiliary_bus.rst Documentation/auxiliary_bus: Move the text into the code 2021-12-03 16:41:50 +01:00
basics.rst overflow: Fix kern-doc markup for functions 2022-10-25 14:57:42 -07:00
clk.rst
component.rst
connector.rst net/connector: Add const qualifier to cb_id 2020-12-16 11:06:49 -08:00
console.rst
dcdbas.rst
devfreq.rst
device_link.rst docs: device_link.rst: remove duplicated kernel-doc include 2020-10-15 07:49:42 +02:00
device-io.rst dma-buf-map: Rename to iosys-map 2022-02-07 16:35:35 -08:00
dma-buf.rst dma-buf: add dma_fence_unwrap v2 2022-03-25 14:18:28 +01:00
edac.rst
eisa.rst
firewire.rst Documentation: fix firewire.rst ABI file path error 2022-01-20 17:01:32 -07:00
frame-buffer.rst
generic-counter.rst counter: Update documentation for new counter registration functions 2021-12-30 17:44:06 +01:00
hsi.rst
i2c.rst
index.rst drm: Implement DRM aperture helpers under video/ 2022-06-27 11:07:55 +02:00
infiniband.rst
infrastructure.rst docs: infrastructure.rst: exclude device_link_state from device.h 2020-10-15 07:49:46 +02:00
input.rst Input: remove input_polled_dev implementation 2020-12-02 12:35:14 -08:00
interconnect.rst
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ioctl.rst docs: driver-api: avoid using ReST :doc:foo markup 2021-06-17 13:24:37 -06:00
ipmb.rst
ipmi.rst ipmi: docs: don't advertise deprecated sysfs entries 2024-10-17 15:20:54 +02:00
isa.rst Remove duplicate words inside documentation 2022-09-27 13:21:43 -06:00
isapnp.rst
libata.rst libata: Improve ATA queued command allocation 2022-04-11 09:27:44 +09:00
mailbox.rst docs: move mailbox.txt to driver-api and rename it 2020-06-26 11:33:38 -06:00
men-chameleon-bus.rst Documentation: document dma device use for mcb 2021-01-11 13:26:13 -07:00
message-based.rst
misc_devices.rst
miscellaneous.rst docs/driver-api/miscellaneous: Remove kernel-doc of serial_core.c 2022-11-09 14:56:05 +01:00
mtdnand.rst docs: mtd: Avoid htmldocs warnings 2020-12-10 22:37:32 +01:00
ntb.rst Documentation/driver-api: ntb: drop doubled word 2020-07-13 11:18:17 -06:00
nvmem.rst doc: nvmem: Update example 2022-02-21 18:00:30 +01:00
parport-lowlevel.rst
pin-control.rst docs/pinctrl: fix the reference to the u300 platform 2021-05-28 02:59:40 +02:00
pps.rst
ptp.rst docs: ptp.rst: add support for Renesas (IDT) ClockMatrix 2020-07-17 10:25:21 -07:00
pwm.rst pwm: core: Get rid of unused devm_of_pwm_get() 2022-09-19 06:17:05 -07:00
regulator.rst docs: get rid of :c:type explicit declarations for structs 2020-10-15 07:49:40 +02:00
reset.rst docs: add a reset controller chapter to the driver API docs 2020-12-08 10:48:04 -07:00
rfkill.rst
s390-drivers.rst
scsi.rst
slimbus.rst
sm501.rst
spi.rst spi: Update reference to struct spi_controller 2022-12-31 13:32:06 +01:00
switchtec.rst
sync_file.rst
target.rst docs: scsi: target.rst: remove iSCSI transport class kernel-doc markup 2020-10-15 07:49:42 +02:00
uio-howto.rst Documentation/driver-api: uio-howto: drop doubled word 2020-07-10 14:58:01 +02:00
vfio-mediated-device.rst vfio/mdev: consolidate all the description sysfs into the core code 2022-10-04 12:06:58 -06:00
vfio-pci-device-specific-driver-acceptance.rst vfio-pci: Provide reviewers and acceptance criteria for variant drivers 2022-03-17 09:57:11 -06:00
vfio.rst vfio: Introduce a vfio_uninit_group_dev() API call 2021-08-11 09:50:10 -06:00
vme.rst vme: move back to staging 2022-06-10 15:38:14 +02:00
w1.rst
xillybus.rst Documentation/driver-api: xillybus: drop doubled word 2020-07-10 14:58:01 +02:00
zorro.rst