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RTS polarity of rs485-enabled ports is currently initialized on uart
open via:
tty_port_open()
tty_port_block_til_ready()
tty_port_raise_dtr_rts() # if (C_BAUD(tty))
uart_dtr_rts()
uart_port_dtr_rts()
There's at least three problems here:
First, if no baud rate is set, RTS polarity is not initialized.
That's the right thing to do for rs232, but not for rs485, which
requires that RTS is deasserted unconditionally.
Second, if the DeviceTree property "linux,rs485-enabled-at-boot-time" is
present, RTS should be deasserted as early as possible, i.e. on probe.
Otherwise it may remain asserted until first open.
Third, even though RTS is deasserted on open and close, it may
subsequently be asserted by uart_throttle(), uart_unthrottle() or
uart_set_termios() because those functions aren't rs485-aware.
(Only uart_tiocmset() is.)
To address these issues, move RTS initialization from uart_port_dtr_rts()
to uart_configure_port(). Prevent subsequent modification of RTS
polarity by moving the existing rs485 check from uart_tiocmget() to
uart_update_mctrl().
That way, RTS is initialized on probe and then remains unmodified unless
the uart transmits data. If rs485 is enabled at runtime (instead of at
boot) through a TIOCSRS485 ioctl(), RTS is initialized by the uart
driver's ->rs485_config() callback and then likewise remains unmodified.
The PL011 driver initializes RTS on uart open and prevents subsequent
modification in its ->set_mctrl() callback. That code is obsoleted by
the present commit, so drop it.
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Su Bao Cheng <baocheng.su@siemens.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/2d2acaf3a69e89b7bf687c912022b11fd29dfa1e.1642909284.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit 8d479237727c ("serial: amba-pl011: add RS485 support") sought to
keep RTS deasserted on set_mctrl if rs485 is enabled. However it did so
only if deasserted RTS polarity is high. Fix it in case it's low.
Fixes: 8d479237727c ("serial: amba-pl011: add RS485 support")
Cc: stable@vger.kernel.org # v5.15+
Cc: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Jochen Mades <jochen@mades.net>
[lukas: copyedit commit message, add stable designation]
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/85fa3323ba8c307943969b7343e23f34c3e652ba.1642909284.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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x_char is ignored by stm32_usart_start_tx() when xmit buffer is empty.
Fix start_tx condition to allow x_char to be sent.
Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220111164441.6178-3-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When sending x_char in stm32_usart_transmit_chars(), driver can overwrite
the value of TDR register by the value of x_char. If this happens, the
previous value that was present in TDR register will not be sent through
uart.
This code checks if the previous value in TDR register is sent before
writing the x_char value into register.
Fixes: 48a6092fb41f ("serial: stm32-usart: Add STM32 USART Driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220111164441.6178-2-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010.
See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516
The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to
the newer 27.010 here. Chapter 5.2.7.3 states that DC1 (XON) and DC3 (XOFF)
are the control characters defined in ISO/IEC 646. These shall be quoted if
seen in the data stream to avoid interpretation as flow control characters.
ISO/IEC 646 refers to the set of ISO standards described as the ISO
7-bit coded character set for information interchange. Its final version
is also known as ITU T.50.
See https://www.itu.int/rec/T-REC-T.50-199209-I/en
To abide the standard it is needed to quote DC1 and DC3 correctly if these
are seen as data bytes and not as control characters. The current
implementation already tries to enforce this but fails to catch all
defined cases. 3GPP 27.010 chapter 5.2.7.3 clearly states that the most
significant bit shall be ignored for DC1 and DC3 handling. The current
implementation handles only the case with the most significant bit set 0.
Cases in which DC1 and DC3 have the most significant bit set 1 are left
unhandled.
This patch fixes this by masking the data bytes with ISO_IEC_646_MASK (only
the 7 least significant bits set 1) before comparing them with XON
(a.k.a. DC1) and XOFF (a.k.a. DC3) when testing which byte values need
quotation via byte stuffing.
Fixes: e1eaea46bb40 ("tty: n_gsm line discipline")
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20220120101857.2509-1-daniel.starke@siemens.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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8250_of supports a reg-offset property which is intended to handle
cases where the device registers start at an offset inside the region
of memory allocated to the device. The Xilinx 16550 UART, for which this
support was initially added, requires this. However, the code did not
adjust the overall size of the mapped region accordingly, causing the
driver to request an area of memory past the end of the device's
allocation. For example, if the UART was allocated an address of
0xb0130000, size of 0x10000 and reg-offset of 0x1000 in the device
tree, the region of memory reserved was b0131000-b0140fff, which caused
the driver for the region starting at b0140000 to fail to probe.
Fix this by subtracting reg-offset from the mapped region size.
Fixes: b912b5e2cfb3 ([POWERPC] Xilinx: of_serial support for Xilinx uart 16550.)
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Robert Hancock <robert.hancock@calian.com>
Link: https://lore.kernel.org/r/20220112194214.881844-1-robert.hancock@calian.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The tty_port struct is part of the rpmsg_tty_port structure.
The issue is that the rpmsg_tty_port structure is freed on
rpmsg_tty_remove while it is still referenced in the tty_struct.
Its release is not predictable due to workqueues.
For instance following ftrace shows that rpmsg_tty_close is called after
rpmsg_tty_release_cport:
nr_test.sh-389 [000] ..... 212.093752: rpmsg_tty_remove <-rpmsg_dev_
remove
cat-1191 [001] ..... 212.095697: tty_release <-__fput
nr_test.sh-389 [000] ..... 212.099166: rpmsg_tty_release_cport <-rpm
sg_tty_remove
cat-1191 [001] ..... 212.115352: rpmsg_tty_close <-tty_release
cat-1191 [001] ..... 212.115371: release_tty <-tty_release_str
As consequence, the port must be free only when user has released the TTY
interface.
This path :
- Introduce the .destruct port tty ops function to release the allocated
rpmsg_tty_port structure.
- Introduce the .hangup tty ops function to call tty_port_hangup.
- Manages the tty port refcounting to trig the .destruct port ops,
- Introduces the rpmsg_tty_cleanup function to ensure that the TTY is
removed before decreasing the port refcount.
Fixes: 7c0408d80579 ("tty: add rpmsg driver")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Arnaud Pouliquen <arnaud.pouliquen@foss.st.com>
Link: https://lore.kernel.org/r/20220104163545.34710-1-arnaud.pouliquen@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This commit adds support for the some of the Brainboxes PCI range of
cards, including the UC-101, UC-235/246, UC-257, UC-268, UC-275/279,
UC-302, UC-310, UC-313, UC-320/324, UC-346, UC-357, UC-368
and UC-420/431.
Signed-off-by: Cameron Williams <cang1@live.co.uk>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/AM5PR0202MB2564688493F7DD9B9C610827C45E9@AM5PR0202MB2564.eurprd02.prod.outlook.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This reverts commit 5021d709b31b8a14317998a33cbc78be0de9ab30.
The patch is still a bit buggy, and this breaks some other hardware
types. It needs to be resubmitted in a non-buggy way, and make sure the
other hardware types also continue to work properly.
Fixes: 5021d709b31b ("tty: serial: Use fifo in 8250 console driver")
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Link: https://lore.kernel.org/r/Ye/1+Z8mEzbKbrqG@linutronix.de
Link: https://lore.kernel.org/r/a1ac6254-f79e-d131-fa2a-c7ad714c6d4a@nvidia.com
Cc: Wander Lairson Costa <wander@redhat.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Pull bitmap updates from Yury Norov:
- introduce for_each_set_bitrange()
- use find_first_*_bit() instead of find_next_*_bit() where possible
- unify for_each_bit() macros
* tag 'bitmap-5.17-rc1' of git://github.com/norov/linux:
vsprintf: rework bitmap_list_string
lib: bitmap: add performance test for bitmap_print_to_pagebuf
bitmap: unify find_bit operations
mm/percpu: micro-optimize pcpu_is_populated()
Replace for_each_*_bit_from() with for_each_*_bit() where appropriate
find: micro-optimize for_each_{set,clear}_bit()
include/linux: move for_each_bit() macros from bitops.h to find.h
cpumask: replace cpumask_next_* with cpumask_first_* where appropriate
tools: sync tools/bitmap with mother linux
all: replace find_next{,_zero}_bit with find_first{,_zero}_bit where appropriate
cpumask: use find_first_and_bit()
lib: add find_first_and_bit()
arch: remove GENERIC_FIND_FIRST_BIT entirely
include: move find.h from asm_generic to linux
bitops: move find_bit_*_le functions from le.h to find.h
bitops: protect find_first_{,zero}_bit properly
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find_first{,_zero}_bit is a more effective analogue of 'next' version if
start == 0. This patch replaces 'next' with 'first' where things look
trivial.
Signed-off-by: Yury Norov <yury.norov@gmail.com>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound
Pull sound updates from Takashi Iwai:
"It's a relatively calm development cycle, but still lots of updates in
the driver side like Intel SOF. Below are some highlights:
ALSA / ASoC core:
- A new kselftest for ALSA control API
- PCM NO_REWINDS support
- Potential race fixes around control removals
- Unify x86 SG-buffer memory allocation code
- Cleanups and race fixes for ASoC DPCM locking
ASoC:
- Refinements and cleanups around the delay() APIs
- Wider use of dev_err_probe().
- Continuing cleanups and improvements to the SOF code
- Support for pin switches in simple-card derived cards
- Support for AMD Renoir ACP, Asahi Kasei Microdevices AKM4375, Intel
systems using NAU8825 and MAX98390, Mediatek MT8915, nVidia Tegra20
S/PDIF, Qualcomm systems using ALC5682I-VS and Texas Instruments
TLV320ADC3xxx
HD-audio / USB-audio:
- Fix deadlock at HD-audio codec unbinding
- Fixes for Tegra194 HD-audio, new HDA support for CS35L41 codec
- Quirks for Lenovo and HP machines, Gigabyte mobo, Bose device
Misc:
- Fix virmidi drain behavior
Note that the merge of CS35L41 codec support is still half-baked, and
at least one ACPI change is missing. Although this won't hinder the
kernel build itself, we're going to catch up before RC1"
* tag 'sound-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (415 commits)
ALSA: hda: intel-dsp-config: reorder the config table
ALSA: hda: intel-dsp-config: add JasperLake support
ALSA: hda: cs35l41: fix double free on error in probe()
ALSA: hda: Fix dependencies of CS35L41 on SPI/I2C buses
ALSA: hda: Fix dependency on ASoC cs35l41 codec
ASoC: cs35l41: Add support for hibernate memory retention mode
ASoC: cs35l41: Update handling of test key registers
ALSA: intel_hdmi: Check for error num after setting mask
ASoC: wcd9335: Keep a RX port value for each SLIM RX mux
ASoC: amd: acp: acp-mach: Change default RT1019 amp dev id
ALSA: virmidi: Remove duplicated code
ALSA: seq: virmidi: Add a drain operation
ASoC: topology: Fix typo
ASoC: fsl_asrc: refine the check of available clock divider
ASoC: Intel: bytcr_rt5640: Add support for external GPIO jack-detect
ASoC: Intel: bytcr_rt5640: Support retrieving the codec IRQ from the AMCR0F28 ACPI dev
ASoC: rt5640: Add support for boards with an external jack-detect GPIO
ASoC: rt5640: Allow snd_soc_component_set_jack() to override the codec IRQ
ASoC: rt5640: Change jack_work to a delayed_work
ASoC: rt5640: Fix possible NULL pointer deref on resume
...
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial driver updates from Greg KH:
"Here is the big set of tty/serial driver updates for 5.17-rc1.
Nothing major in here, just lots of good updates and fixes, including:
- more tty core cleanups from Jiri as well as mxser driver cleanups.
This is the majority of the core diffstat
- tty documentation updates from Jiri
- platform_get_irq() updates
- various serial driver updates for new features and hardware
- fifo usage for 8250 console, reducing cpu load a lot
- LED fix for keyboards, long-time bugfix that went through many
revisions
- minor cleanups
All have been in linux-next for a while with no reported problems"
* tag 'tty-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (119 commits)
serial: core: Keep mctrl register state and cached copy in sync
serial: stm32: correct loop for dma error handling
serial: stm32: fix flow control transfer in DMA mode
serial: stm32: rework TX DMA state condition
serial: stm32: move tx dma terminate DMA to shutdown
serial: pl011: Drop redundant DTR/RTS preservation on close/open
serial: pl011: Drop CR register reset on set_termios
serial: pl010: Drop CR register reset on set_termios
serial: liteuart: fix MODULE_ALIAS
serial: 8250_bcm7271: Fix return error code in case of dma_alloc_coherent() failure
Revert "serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2"
tty: goldfish: Use platform_get_irq() to get the interrupt
serdev: BREAK/FRAME/PARITY/OVERRUN notification prototype V2
tty: serial: meson: Drop the legacy compatible strings and clock code
serial: pmac_zilog: Use platform_get_irq() to get the interrupt
serial: bcm63xx: Use platform_get_irq() to get the interrupt
serial: ar933x: Use platform_get_irq() to get the interrupt
serial: vt8500: Use platform_get_irq() to get the interrupt
serial: altera_jtaguart: Use platform_get_irq_optional() to get the interrupt
serial: pxa: Use platform_get_irq() to get the interrupt
...
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI updates from Rafael Wysocki:
"These are usual ACPICA code updates (although there are more of them
than in the last few releases), a noticeable EC driver update (which
mostly consists of cleanups, though), the device enumeration quirks
handling rework from Hans, some updates eliminating unnecessary CPU
cache flushing in some places (processor idle and system-wide PM code)
and a bunch of assorted cleanups and fixes.
Specifics:
- Update ACPICA code in the kernel to the 20211217 upstream release
including the following changes:
- iASL/Disassembler: Additional support for NHLT table (Bob
Moore).
- Change a return_ACPI_STATUS (AE_BAD_PARAMETER) (Bob Moore).
- Fix a couple of warnings under MSVC (Bob Moore).
- iASL: Add TDEL table to both compiler/disassembler (Bob Moore).
- iASL/NHLT table: "Specific Data" field support (Bob Moore).
- Use original data_table_region pointer for accesses (Jessica
Clarke).
- Use original pointer for virtual origin tables (Jessica Clarke).
- Macros: Remove ACPI_PHYSADDR_TO_PTR (Jessica Clarke).
- Avoid subobject buffer overflow when validating RSDP signature
(Jessica Clarke).
- iASL: Add suppport for AGDI table (Ilkka Koskinen).
- Hardware: Do not flush CPU cache when entering S4 and S5 (Kirill
A. Shutemov).
- Expand the ACPI_ACCESS_ definitions (Mark Langsdorf).
- Utilities: Avoid deleting the same object twice in a row (Rafael
Wysocki).
- Executer: Fix REFCLASS_REFOF case in acpi_ex_opcode_1A_0T_1R()
(Rafael Wysocki).
- Fix AEST Processor generic resource substructure data field byte
length (Shuuichirou Ishii).
- Fix wrong interpretation of PCC address (Sudeep Holla).
- Add support for PCC Opregion special context data (Sudeep
Holla).
- Implement OperationRegion handler for PCC Type 3 subtype (Sudeep
Holla).
- Introduce acpi_fetch_acpi_dev() as a replacement for
acpi_bus_get_device() and use it in the ACPI subsystem (Rafael
Wysocki).
- Avoid using _CID for device enumaration if _HID is missing or
invalid (Rafael Wysocki).
- Rework quirk handling during ACPI device enumeration and add some
new quirks for known broken platforms (Hans de Goede).
- Avoid unnecessary or redundant CPU cache flushing during system PM
transitions (Kirill A. Shutemov).
- Add PM debug messages related to power resources (Rafael Wysocki).
- Fix kernel-doc comment in the PCI host bridge ACPI driver (Yang
Li).
- Rework flushing of EC work while suspended to idle and clean up the
handling of events in the ACPI EC driver (Rafael Wysocki).
- Prohibit ec_sys module parameter write_support from being used when
the system is locked down (Hans de Goede).
- Make the ACPI processor thermal driver use cpufreq_cpu_get() to
check for presence of cpufreq policy (Manfred Spraul).
- Avoid unnecessary CPU cache flushing in the ACPI processor idle
driver (Kirill A. Shutemov).
- Replace kernel.h with the necessary inclusions in the ACPI
processor driver (Andy Shevchenko).
- Use swap() instead of open coding it in the ACPI processor idle
driver (Guo Zhengkui).
- Fix the handling of defective LPAT in the ACPI xpower PMIC driver
and clean up some definitions of PMIC data structures (Hans de
Goede).
- Fix outdated comment in the ACPI DPTF driver (Sumeet Pawnikar).
- Add AEST to the list of known ACPI table signatures (Shuuichirou
Ishii).
- Make ACPI NUMA code take hotpluggable memblocks into account when
CONFIG_MEMORY_HOTPLUG is not set (Vitaly Kuznetsov).
- Use default_groups in kobj_type in the ACPI sysfs code (Greg
Kroah-Hartman).
- Rearrange _CPC structure documentation (Andy Shevchenko).
- Drop an always true check from the ACPI thermal driver (Adam
Borowski).
- Add new "not charging" quirk for Lenovo ThinkPads to the ACPI
battery driver (Thomas Weißschuh)"
* tag 'acpi-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (64 commits)
ACPI: PCC: Implement OperationRegion handler for the PCC Type 3 subtype
ACPI / x86: Skip AC and battery devices on x86 Android tablets with broken DSDTs
ACPI / x86: Introduce an acpi_quirk_skip_acpi_ac_and_battery() helper
ACPI: processor: thermal: avoid cpufreq_get_policy()
serdev: Do not instantiate serdevs on boards with known bogus DSDT entries
i2c: acpi: Do not instantiate I2C-clients on boards with known bogus DSDT entries
ACPI / x86: Add acpi_quirk_skip_[i2c_client|serdev]_enumeration() helpers
ACPI: scan: Create platform device for BCM4752 and LNV4752 ACPI nodes
PCI/ACPI: Fix acpi_pci_osc_control_set() kernel-doc comment
ACPI: battery: Add the ThinkPad "Not Charging" quirk
ACPI: sysfs: use default_groups in kobj_type
ACPICA: Update version to 20211217
ACPICA: iASL/NHLT table: "Specific Data" field support
ACPICA: iASL: Add suppport for AGDI table
ACPICA: iASL: Add TDEL table to both compiler/disassembler
ACPICA: Fixed a couple of warnings under MSVC
ACPICA: Change a return_ACPI_STATUS (AE_BAD_PARAMETER)
ACPICA: Hardware: Do not flush CPU cache when entering S4 and S5
ACPICA: Add support for PCC Opregion special context data
ACPICA: Fix wrong interpretation of PCC address
...
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Pull RISC-V SoC updates from Arnd Bergmann:
"Add support for StarFive JH7100 RISC-V SoC
This adds support for the StarFive JH7100, including the necessary
device drivers and DT files for the BeagleV Starlight prototype board,
with additional boards to be added later. This SoC promises to be the
first usable low-cost platform for RISC-V.
I've taken this through the SoC tree in the anticipation of adding a
few other Arm based SoCs as well, but those did not pass the review in
time, so it's only this one"
* tag 'newsoc-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
reset: starfive-jh7100: Fix 32bit compilation
RISC-V: Add BeagleV Starlight Beta device tree
RISC-V: Add initial StarFive JH7100 device tree
serial: 8250_dw: Add StarFive JH7100 quirk
dt-bindings: serial: snps-dw-apb-uart: Add JH7100 uarts
pinctrl: starfive: Add pinctrl driver for StarFive SoCs
dt-bindings: pinctrl: Add StarFive JH7100 bindings
dt-bindings: pinctrl: Add StarFive pinctrl definitions
reset: starfive-jh7100: Add StarFive JH7100 reset driver
dt-bindings: reset: Add Starfive JH7100 reset bindings
dt-bindings: reset: Add StarFive JH7100 reset definitions
clk: starfive: Add JH7100 clock generator driver
dt-bindings: clock: starfive: Add JH7100 bindings
dt-bindings: clock: starfive: Add JH7100 clock definitions
dt-bindings: interrupt-controller: Add StarFive JH7100 plic
dt-bindings: timer: Add StarFive JH7100 clint
RISC-V: Add StarFive SoC Kconfig option
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Merge ACPI device enumeration updates, ACPI power management updates
and PCI host bridge ACPI driver updates for 5.17-rc1:
- Introduce acpi_fetch_acpi_dev() as a replacement for
acpi_bus_get_device() and use it in the ACPI subsystem (Rafael
Wysocki).
- Avoid using _CID for device enumaration if _HID is missing or
invalid (Rafael Wysocki).
- Rework quirk handling during ACPI device enumeration and add some
new quirks for known broken platforms (Hans de Goede).
- Avoid unnecessary or redundant CPU cache flushing during system
PM transitions (Kirill A. Shutemov).
- Add PM debug messages related to power resources (Rafael Wysocki).
- Fix kernel-doc comment in the PCI host bridge ACPI driver (Yang Li).
* acpi-scan:
serdev: Do not instantiate serdevs on boards with known bogus DSDT entries
i2c: acpi: Do not instantiate I2C-clients on boards with known bogus DSDT entries
ACPI / x86: Add acpi_quirk_skip_[i2c_client|serdev]_enumeration() helpers
ACPI: scan: Create platform device for BCM4752 and LNV4752 ACPI nodes
ACPI: Use acpi_fetch_acpi_dev() instead of acpi_bus_get_device()
ACPI: scan: Introduce acpi_fetch_acpi_dev()
ACPI: scan: Do not add device IDs from _CID if _HID is not valid
* acpi-pm:
ACPI: PM: Remove redundant cache flushing
ACPI: PM: Avoid CPU cache flush when entering S4
* acpi-power:
ACPI: PM: Emit debug messages when enabling/disabling wakeup power
* acpi-pci:
PCI/ACPI: Fix acpi_pci_osc_control_set() kernel-doc comment
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struct uart_port contains a cached copy of the Modem Control signals.
It is used to skip register writes in uart_update_mctrl() if the new
signal state equals the old signal state. It also avoids a register
read to obtain the current state of output signals.
When a uart_port is registered, uart_configure_port() changes signal
state but neglects to keep the cached copy in sync. That may cause
a subsequent register write to be incorrectly skipped. Fix it before
it trips somebody up.
This behavior has been present ever since the serial core was introduced
in 2002:
https://git.kernel.org/history/history/c/33c0d1b0c3eb
So far it was never an issue because the cached copy is initialized to 0
by kzalloc() and when uart_configure_port() is executed, at most DTR has
been set by uart_set_options() or sunsu_console_setup(). Therefore,
a stable designation seems unnecessary.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/bceeaba030b028ed810272d55d5fc6f3656ddddb.1641129752.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
In this error handling, "transmit_chars_dma" function will call
"transmit_chars_pio" once per characters. But "transmit_chars_pio" will
continue to send characters while xmit buffer is not empty.
Remove this useless loop, one call is sufficient.
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220104182445.4195-5-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
If flow control is enabled, framework will call stop_tx to
pause transfer and then call start_tx to resume transfer.
Clear USART_CR3_DMAT bit in stop_tx ops to pause DMA transfer.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220104182445.4195-4-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
TX DMA state condition is handled by tx_dma_busy boolean.
This boolean is set when dma descriptor is requested and reset when dma
channel is stopped (dma_terminate).
In stm32_usart_serial_remove(), stm32_usart_stop_tx() and
stm32_usart_transmit_chars_dma() fallback error case, DMA channel is
stopped but tx_dma_busy is not handled.
Rework the driver by using two new functions to solve this issue:
- stm32_usart_tx_dma_started return true if DMA TX have a descriptor.
- stm32_usart_tx_dma_enabled return true if DMAT bit is set.
stm32_usart_tx_dma_started uses tx_dma_busy flag to prevent dual DMA
transaction at the same time. This flag is set when a DMA transaction
begins and is unset when dmaengine_terminate_async function is called.
A new DMA transaction cannot be created if this flag is set.
Create a new function "stm32_usart_tx_dma_terminate" to be sure the flag
is unset after each call of dmaengine_terminate_async.
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220104182445.4195-3-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Terminate DMA transaction and clear CR3_DMAT when shutdown is requested,
instead of when remove is requested. If DMA transfer is not stopped in
shutdown ops, driver will fail to start a new DMA transfer after next
startup ops.
Fixes: 3489187204eb ("serial: stm32: adding dma support")
Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com>
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20220104182445.4195-2-valentin.caron@foss.st.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Commit d8d8ffa47783 ("amba-pl011: do not disable RTS during shutdown")
amended the PL011 serial driver to leave DTR/RTS polarity untouched on
tty close. That change made sense.
But the commit also added code to save DTR/RTS state to an internal
variable on tty close and restore it on tty open. That part of the
commit makes less sense: The driver has no ->pm() callback, so the uart
remains powered after tty close and automatically preserves register
state, including DTR/RTS.
Saving and restoring registers isn't the job of the ->startup() and
->shutdown() callbacks anyway. Rather, it should happen in ->pm().
Additionally, after pl011_startup() restores the state, the serial core
overrides it in uart_port_dtr_rts() if a baud rate has been set:
tty_port_open()
uart_port_activate()
uart_startup()
uart_port_startup()
pl011_startup() # restores DTR/RTS from uap->old_cr
tty_port_block_til_ready()
tty_port_raise_dtr_rts # if (C_BAUD(tty))
uart_dtr_rts()
uart_port_dtr_rts() # raises DTR/RTS
The serial core also overrides DTR/RTS on tty close in uart_shutdown()
if C_HUPCL(tty) is set. So a user-defined DTR/RTS polarity won't
survive a close/open cycle anyway, unless the user has set the baud rate
to zero and disabled hupcl on the tty.
Bottom line is, the code to save and restore DTR/RTS has no effect.
Remove it.
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/e22089ab49e6e78822c50c8c4db46bf3ee885623.1641129328.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
pl011_set_termios() briefly resets the CR register to zero, thereby
glitching DTR/RTS signals. With rs485 this may result in the bus being
occupied for no reason.
Where does this register write originate from?
The PL011 driver was forked from the PL010 driver in 2004:
https://git.kernel.org/history/history/c/157c0342e591
Until this commit, the PL010 driver's IRQ handler ambauart_int()
modified the CR register without holding the port spinlock.
ambauart_set_termios() also modified that register. To prevent
concurrent read-modify-writes by the IRQ handler and to prevent
transmission while changing baudrate, ambauart_set_termios() had to
disable interrupts. On the PL010, that is achieved by writing zero to
the CR register.
However, on the PL011, interrupts are disabled in the IMSC register,
not in the CR register.
Additionally, the commit amended both the PL010 and PL011 driver to
acquire the port spinlock in the IRQ handler, obviating the need to
disable interrupts in ->set_termios().
So the CR register write is obsolete for two reasons. Drop it.
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/f49f945375f5ccb979893c49f1129f51651ac738.1641129062.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
pl010_set_termios() briefly resets the CR register to zero.
Where does this register write come from?
The PL010 driver's IRQ handler ambauart_int() originally modified the CR
register without holding the port spinlock. ambauart_set_termios() also
modified that register. To prevent concurrent read-modify-writes by the
IRQ handler and to prevent transmission while changing baudrate,
ambauart_set_termios() had to disable interrupts. That is achieved by
writing zero to the CR register.
However in 2004 the PL010 driver was amended to acquire the port
spinlock in the IRQ handler, obviating the need to disable interrupts in
->set_termios():
https://git.kernel.org/history/history/c/157c0342e591
That rendered the CR register write obsolete. Drop it.
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/fcaff16e5b1abb4cc3da5a2879ac13f278b99ed0.1641128728.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
modprobe can't handle spaces in aliases.
Fixes: 1da81e5562fa ("drivers/tty/serial: add LiteUART driver")
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Link: https://lore.kernel.org/r/20220104131030.1674733-1-hi@alyssa.is
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
failure
In case of dma_alloc_coherent() failure return -ENOMEM instead of
returning -EINVAL.
Reported-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20220105180704.8989-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
This reverts commit d8e9a406a931f687945703a4bac45042eb81ce92.
It needs some future changes as pointed out by Johan and is not ready to
be merged just yet.
Reported-by: Johan Hovold <johan@kernel.org>
Cc: Magnus Damm <damm+renesas@opensource.se>
Link: https://lore.kernel.org/r/Yc7oZ/1tu95Z4wPS@hovoldconsulting.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
x86 ACPI devices which ship with only Android as their factory image use
older kernels which do not yet support ACPI serdev enumeration, as such
the serdev information in their ACPI tables is not reliable.
For example on the Asus ME176C tablet the serdev describing the Bluetooth
HCI points to the serdev_controller connected to the GPS and the other way
around.
Use the new acpi_quirk_skip_serdev_enumeration() helper to identify
known boards with this issue and then either abort adding the serdev
controller (creating a tty cdev instead) or only create the controller
leaving the instantation of the serdev itself up to platform code.
In the case where only the serdev controller is created the necessary
serdevs will instead be instantiated by the
drivers/platform/x86/x86-android-tablets.c kernel module.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224153753.22210-1-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Allow serdev device drivers get notified by hardware errors such as BREAK,
FRAME, PARITY and OVERRUN.
With this patch, in the event of an error detected in the UART device driver
the serdev_device_driver will get the newly introduced ->error() callback
invoked if serdev_device_set_error_mask() has previously been used to enable
the type of error. The errors are taken straight from the TTY layer and fed
into the serdev_device_driver after filtering out only enabled errors.
Without this patch the hardware errors never reach the serdev_device_driver.
Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Link: https://lore.kernel.org/r/163931528842.27756.3665040315954968747.sendpatchset@octo
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
All mainline .dts files have been using the stable UART since Linux
4.16. Drop the legacy compatible strings and related clock code.
Signed-off-by: Yu Tu <yu.tu@amlogic.com>
Link: https://lore.kernel.org/r/20211230102110.3861-2-yu.tu@amlogic.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-11-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-10-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-9-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-8-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq_optional().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-7-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-6-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-5-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
In case of failures brcmuart_probe() always returned -ENODEV, this
isn't correct for example platform_get_irq_byname() may return
-EPROBE_DEFER to handle such cases propagate error codes in
brcmuart_probe() in case of failures.
Fixes: 41a469482de25 ("serial: 8250: Add new 8250-core based Broadcom STB driver")
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-4-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq().
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-3-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_resource(pdev, IORESOURCE_IRQ, ..) relies on static
allocation of IRQ resources in DT core code, this causes an issue
when using hierarchical interrupt domains using "interrupts" property
in the node as this bypasses the hierarchical setup and messes up the
irq chaining.
In preparation for removal of static setup of IRQ resource from DT core
code use platform_get_irq_optional().
Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Link: https://lore.kernel.org/r/20211224142917.6966-2-prabhakar.mahadev-lad.rj@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
platform_get_irq() returns signed status. It should be stored and
compared as signed value before storing to unsigned variable. Implicit
conversion from signed to unsigned and then comparison with less than
zero is wrong as unsigned value can never be less than zero.
Fixes: f087f01ca2c5 ("serial: lantiq: Use platform_get_irq() to get the interrupt")
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Link: https://lore.kernel.org/r/YcIf7+oSWWn34ND6@debian-BULLSEYE-live-builder-AMD64
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
struct uart_8250_port contains mcr_mask and mcr_force members whose
sole purpose is to work around an Alpha-specific quirk. This code
doesn't belong in the core where it is executed by everyone else,
so move it to a proper ->set_mctrl callback which is used on the
affected Alpha machine only.
The quirk was introduced in January 1995:
https://git.kernel.org/pub/scm/linux/kernel/git/history/history.git/diff/drivers/char/serial.c?h=1.1.83
The members in struct uart_8250_port were added in 2002:
https://git.kernel.org/history/history/c/4524aad27854
The quirk applies to non-PCI Alphas and arch/alpha/Kconfig specifies
"select FORCE_PCI if !ALPHA_JENSEN". So apparently the only affected
machine is the EISA-based Jensen that Linus was working on back then:
https://lore.kernel.org/all/CAHk-=wj1JWZ3sCrGz16nxEj7=0O+srMg6Ah3iPTDXSPKEws_SA@mail.gmail.com/
Up until now the quirk is not applied unless CONFIG_PCI is disabled.
If users forget to do that or run a generic Alpha kernel, the serial
ports aren't usable on Jensen. Avoid by confining the quirk to
CONFIG_ALPHA_JENSEN instead of !CONFIG_PCI. On generic Alpha kernels,
auto-detect at runtime whether the quirk needs to be applied.
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Cc: Ulrich Teichert <krypton@ulrich-teichert.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/b83d069cb516549b8a5420e097bb6bdd806f36fc.1640695609.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Commit a6845e1e1b78 ("serial: core: Consider rs485 settings to drive
RTS") sought to deassert RTS when opening an rs485-enabled uart port.
That way, the transceiver does not occupy the bus until it transmits
data.
Unfortunately, the commit mixed up the logic and *asserted* RTS instead
of *deasserting* it:
The commit amended uart_port_dtr_rts(), which raises DTR and RTS when
opening an rs232 port. "Raising" actually means lowering the signal
that's coming out of the uart, because an rs232 transceiver not only
changes a signal's voltage level, it also *inverts* the signal. See
the simplified schematic in the MAX232 datasheet for an example:
https://www.ti.com/lit/ds/symlink/max232.pdf
So, to raise RTS on an rs232 port, TIOCM_RTS is *set* in port->mctrl
and that results in the signal being driven low.
In contrast to rs232, the signal level for rs485 Transmit Enable is the
identity, not the inversion: If the transceiver expects a "high" RTS
signal for Transmit Enable, the signal coming out of the uart must also
be high, so TIOCM_RTS must be *cleared* in port->mctrl.
The commit did the exact opposite, but it's easy to see why given the
confusing semantics of rs232 and rs485. Fix it.
Fixes: a6845e1e1b78 ("serial: core: Consider rs485 settings to drive RTS")
Cc: stable@vger.kernel.org # v4.14+
Cc: Rafael Gago Castano <rgc@hms.se>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Su Bao Cheng <baocheng.su@siemens.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/9395767847833f2f3193c49cde38501eeb3b5669.1639821059.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Note: I am using a small test app + driver located at [0] for the
problem description. serco is a driver whose write function dispatches
to the serial controller. sertest is a user-mode app that writes n bytes
to the serial console using the serco driver.
While investigating a bug in the RHEL kernel, I noticed that the serial
console throughput is way below the configured speed of 115200 bps in
a HP Proliant DL380 Gen9. I was expecting something above 10KB/s, but
I got 2.5KB/s.
$ time ./sertest -n 2500 /tmp/serco
real 0m0.997s
user 0m0.000s
sys 0m0.997s
With the help of the function tracer, I then noticed the serial
controller was taking around 410us seconds to dispatch one single byte:
$ trace-cmd record -p function_graph -g serial8250_console_write \
./sertest -n 1 /tmp/serco
$ trace-cmd report
| serial8250_console_write() {
0.384 us | _raw_spin_lock_irqsave();
1.836 us | io_serial_in();
1.667 us | io_serial_out();
| uart_console_write() {
| serial8250_console_putchar() {
| wait_for_xmitr() {
1.870 us | io_serial_in();
2.238 us | }
1.737 us | io_serial_out();
4.318 us | }
4.675 us | }
| wait_for_xmitr() {
1.635 us | io_serial_in();
| __const_udelay() {
1.125 us | delay_tsc();
1.429 us | }
...
...
...
1.683 us | io_serial_in();
| __const_udelay() {
1.248 us | delay_tsc();
1.486 us | }
1.671 us | io_serial_in();
411.342 us | }
In another machine, I measured a throughput of 11.5KB/s, with the serial
controller taking between 80-90us to send each byte. That matches the
expected throughput for a configuration of 115200 bps.
This patch changes the serial8250_console_write to use the 16550 fifo
if available. In my benchmarks I got around 25% improvement in the slow
machine, and no performance penalty in the fast machine.
Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20211222112831.1968392-2-wander@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use the "ctrl+alt+Fn" key combination to switch the system from tty to
desktop or switch the system from desktop to tty. After the switch is
completed, it is found that the state of the keyboard lock is
inconsistent with the state of the keyboard Led light.The reasons are
as follows:
* The desktop environment (Xorg and other services) is bound to a tty
(assuming it is tty1), and the kb->kbdmode attribute value of tty1
will be set to VC_OFF. According to the current code logic, in the
desktop environment, the values of ledstate and kb->ledflagstate
of tty1 will not be modified anymore, so they are always 0.
* When switching between each tty, the final value of ledstate set by
the previous tty is compared with the kb->ledflagstate value of the
current tty to determine whether to set the state of the keyboard
light. The process of switching between desktop and tty is also the
process of switching between tty1 and other ttys. There are two
situations:
- (1) In the desktop environment, tty1 will not set the ledstate,
which will cause when switching from the desktop to other ttys,
if the desktop lights up the keyboard's led, after the switch is
completed, the keyboard's led light will always be on;
- (2) When switching from another tty to the desktop, this
mechanism will trigger tty1 to set the led state. If other tty
lights up the led of the keyboard before switching to the desktop,
the led will be forcibly turned off. This situation should
be avoided.
* The current patch is to solve these problems: When VT is switched,
the keyboard led needs to be set once.Ensure that after the
switch is completed, the state of the keyboard LED is consistent
with the state of the keyboard lock.
Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: lianzhi chang <changlianzhi@uniontech.com>
Link: https://lore.kernel.org/r/20211215125125.10554-1-changlianzhi@uniontech.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When TTY_NO_WRITE_SPLIT is set and 64 KiB chunks are used, allow
vmalloc() fallback. Supply __GFP_RETRY_MAYFAIL to make kmalloc()
preferable over vmalloc() since we may want a better performance.
Note, both current users copy data to another buffer anyway, so
the type of our allocation doesn't affect their expectations.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211220133250.3070-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Delete the redundant word 'are'.
Signed-off-by: Xiang wangx <wangxiang@cdjrlc.com>
Link: https://lore.kernel.org/r/20211208142036.7956-1-wangxiang@cdjrlc.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Update the SCIF serial driver to remove printouts for break, frame, parity
and overrun errors. This reduces the amount of console printouts generated
by the defconfig kernel on R-Car Gen3 for certain use cases. To retrieve
more information about such errors the user may inspect counters. Also these
errors are fed into the TTY layer for further application specific handling.
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Magnus Damm <damm+renesas@opensource.se>
Link: https://lore.kernel.org/r/163884254093.18109.2982470198301927679.sendpatchset@octo
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It's better to stick with standard API to write and read DL value
when the hardware is compatible with it. In case any quirks are
needed it may be easily added in one place rather than modifying
code here and there.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20211122133512.8947-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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