Mark Brown says:
====================
spi: Make remove() return void
This series from Uwe Kleine-König converts the spi remove function to
return void since there is nothing useful that we can do with a failure
and it as more buses are converted it'll enable further work on the
driver core.
====================
Link: https://lore.kernel.org/r/20220228173957.1262628-2-broonie@kernel.org/
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Pull tty/serial driver fixes from Greg KH:
"Here are some small n_gsm and sc16is7xx serial driver fixes for
5.17-rc6.
The n_gsm fixes are from Siemens as it seems they are using the line
discipline and fixing up a number of issues they found in their
testing. The sc16is7xx serial driver fix is for a reported problem
with that chip.
All of these have been in linux-next with no reported problems"
* tag 'tty-5.17-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
sc16is7xx: Fix for incorrect data being transmitted
tty: n_gsm: fix deadlock in gsmtty_open()
tty: n_gsm: fix wrong modem processing in convergence layer type 2
tty: n_gsm: fix wrong tty control line for flow control
tty: n_gsm: fix NULL pointer access due to DLCI release
tty: n_gsm: fix proper link termination after failed open
tty: n_gsm: fix encoding of command/response bit
tty: n_gsm: fix encoding of control signal octet bit DV
UART drivers are meant to use the port spinlock within certain
methods, to protect against reentrancy. The sc16is7xx driver does
very little locking, presumably because when added it triggers
"scheduling while atomic" errors. This is due to the use of mutexes
within the regmap abstraction layer, and the mutex implementation's
habit of sleeping the current thread while waiting for access.
Unfortunately this lack of interlocking can lead to corruption of
outbound data, which occurs when the buffer used for I2C transmission
is used simultaneously by two threads - a work queue thread running
sc16is7xx_tx_proc, and an IRQ thread in sc16is7xx_port_irq, both
of which can call sc16is7xx_handle_tx.
An earlier patch added efr_lock, a mutex that controls access to the
EFR register. This mutex is already claimed in the IRQ handler, and
all that is required is to claim the same mutex in sc16is7xx_tx_proc.
See: https://github.com/raspberrypi/linux/issues/4885
Fixes: 6393ff1c44 ("sc16is7xx: Use threaded IRQ")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
Link: https://lore.kernel.org/r/20220216160802.1026013-1-phil@raspberrypi.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull parisc architecture fixes from Helge Deller:
- Fix miscompilations when function calls are made from inside a
put_user() call
- Drop __init from map_pages() declaration to avoid random boot crashes
- Added #error messages if a 64-bit compiler was used to build a 32-bit
kernel (and vice versa)
- Fix out-of-bound data TLB miss faults in sba_iommu and ccio-dma
drivers
- Add ioread64_lo_hi() and iowrite64_lo_hi() functions to avoid kernel
test robot errors
- Fix link failure when 8250_gsc driver is built without CONFIG_IOSAPIC
* tag 'for-5.17/parisc-3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
serial: parisc: GSC: fix build when IOSAPIC is not set
parisc: Fix some apparent put_user() failures
parisc: Show error if wrong 32/64-bit compiler is being used
parisc: Add ioread64_lo_hi() and iowrite64_lo_hi()
parisc: Fix sglist access in ccio-dma.c
parisc: Fix data TLB miss in sba_unmap_sg
parisc: Drop __init from map_pages declaration
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>
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: 48a6092fb4 ("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>
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: b912b5e2cf ([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>
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
...
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>
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>
Commit d8d8ffa477 ("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>
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().
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>
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>
Commit a6845e1e1b ("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: a6845e1e1b ("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>
On modern Exynos SoCs (like Exynos850) the UART can be implemented as a
part of USI IP-core. In such case, USI driver is used to initialize USI
registers, and it also calls of_platform_populate() to instantiate all
sub-nodes (e.g. serial node) of USI node. When serial driver is
built-in, but USI driver is a module, and CONFIG_SERIAL_SAMSUNG_CONSOLE
is enabled, next call chain will happen when loading USI module from
user space:
usi_init
v
usi_probe
v
of_platform_populate
v
s3c24xx_serial_probe
v
uart_add_one_port
v
uart_configure_port
v
register_console
v
try_enable_new_console
v
s3c24xx_serial_console_setup
But because the serial driver is built-in, and
s3c24xx_serial_console_setup() is marked with __init keyword, that
symbol will discarded and long gone by that time already, causing failed
paging request.
That happens during the next config combination:
EXYNOS_USI=m
SERIAL_SAMSUNG=y
SERIAL_SAMSUNG_CONSOLE=y
That config should be completely possible, so rather than limiting
SERIAL_SAMSUNG choice to "m" only when USI=m, remove __init keyword for
all affected functions.
Signed-off-by: Sam Protsenko <semen.protsenko@linaro.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Link: https://lore.kernel.org/r/20211204195757.8600-6-semen.protsenko@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
