The GPIO controller component of the sc16is7xx driver is setup too
early, which can result in a race condition where another device tries
to utilise the GPIO lines before the sc16is7xx device has finished
initialising.
This issue manifests itself as an Oops when the GPIO lines are configured:
Unable to handle kernel read from unreadable memory at virtual address
...
pc : sc16is7xx_gpio_direction_output+0x68/0x108 [sc16is7xx]
lr : sc16is7xx_gpio_direction_output+0x4c/0x108 [sc16is7xx]
...
Call trace:
sc16is7xx_gpio_direction_output+0x68/0x108 [sc16is7xx]
gpiod_direction_output_raw_commit+0x64/0x318
gpiod_direction_output+0xb0/0x170
create_gpio_led+0xec/0x198
gpio_led_probe+0x16c/0x4f0
platform_drv_probe+0x5c/0xb0
really_probe+0xe8/0x448
driver_probe_device+0xe8/0x138
__device_attach_driver+0x94/0x118
bus_for_each_drv+0x8c/0xe0
__device_attach+0x100/0x1b8
device_initial_probe+0x28/0x38
bus_probe_device+0xa4/0xb0
deferred_probe_work_func+0x90/0xe0
process_one_work+0x1c4/0x480
worker_thread+0x54/0x430
kthread+0x138/0x150
ret_from_fork+0x10/0x1c
This patch moves the setup of the GPIO controller functions to later in the
probe function, ensuring the sc16is7xx device has already finished
initialising by the time other devices try to make use of the GPIO lines.
The error handling has also been reordered to reflect the new
initialisation order.
Co-developed-by: Wen-chien Jesse Sung <jesse.sung@canonical.com>
Signed-off-by: Wen-chien Jesse Sung <jesse.sung@canonical.com>
Signed-off-by: Isaac True <isaac.true@canonical.com>
Link: https://lore.kernel.org/r/20221130105529.698385-1-isaac.true@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull tty/serial driver updates from Greg KH:
"Here is the big set of TTY and Serial driver updates for 6.1-rc1.
Lots of cleanups in here, no real new functionality this time around,
with the diffstat being that we removed more lines than we added!
Included in here are:
- termios unification cleanups from Al Viro, it's nice to finally get
this work done
- tty serial transmit cleanups in various drivers in preparation for
more cleanup and unification in future releases (that work was not
ready for this release)
- n_gsm fixes and updates
- ktermios cleanups and code reductions
- dt bindings json conversions and updates for new devices
- some serial driver updates for new devices
- lots of other tiny cleanups and janitorial stuff. Full details in
the shortlog.
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-6.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (102 commits)
serial: cpm_uart: Don't request IRQ too early for console port
tty: serial: do unlock on a common path in altera_jtaguart_console_putc()
tty: serial: unify TX space reads under altera_jtaguart_tx_space()
tty: serial: use FIELD_GET() in lqasc_tx_ready()
tty: serial: extend lqasc_tx_ready() to lqasc_console_putchar()
tty: serial: allow pxa.c to be COMPILE_TESTed
serial: stm32: Fix unused-variable warning
tty: serial: atmel: Add COMMON_CLK dependency to SERIAL_ATMEL
serial: 8250: Fix restoring termios speed after suspend
serial: Deassert Transmit Enable on probe in driver-specific way
serial: 8250_dma: Convert to use uart_xmit_advance()
serial: 8250_omap: Convert to use uart_xmit_advance()
MAINTAINERS: Solve warning regarding inexistent atmel-usart binding
serial: stm32: Deassert Transmit Enable on ->rs485_config()
serial: ar933x: Deassert Transmit Enable on ->rs485_config()
tty: serial: atmel: Use FIELD_PREP/FIELD_GET
tty: serial: atmel: Make the driver aware of the existence of GCLK
tty: serial: atmel: Only divide Clock Divisor if the IP is USART
tty: serial: atmel: Separate mode clearing between UART and USART
dt-bindings: serial: atmel,at91-usart: Add gclk as a possible USART clock
...
Add information on supported serial_rs485 features.
This driver does not support delay_rts_after_send but the pre-existing
behavior is to return -EINVAL if delay_rts_after_send is non-zero. In
contrast, other drivers that do not support delay_rts_after_send either
zero delay_rts_after_send or do not care (leave the inaccurate value).
As changing this would cause userspace visible impact, the change is
not attempted here. But perhaps it should be still tried (maybe nobody
finds that kind of API oddity significant)?
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20220606100433.13793-21-ilpo.jarvinen@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull tty/serial driver updates from Greg KH:
"Here are the big set of tty and serial driver changes for 5.18-rc1.
Nothing major, some more good cleanups from Jiri and 2 new serial
drivers. Highlights include:
- termbits cleanups
- export symbol cleanups and other core cleanups from Jiri Slaby
- new sunplus and mvebu uart drivers (amazing that people are still
creating new uarts...)
- samsung serial driver cleanups
- ldisc 29 is now "reserved" for experimental/development line
disciplines
- lots of other tiny fixes and cleanups to serial drivers and
bindings
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-5.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (104 commits)
vt_ioctl: fix potential spectre v1 in VT_DISALLOCATE
serial: 8250: fix XOFF/XON sending when DMA is used
tty: serial: samsung: Add ARTPEC-8 support
dt-bindings: serial: samsung: Add ARTPEC-8 UART
serial: sc16is7xx: Clear RS485 bits in the shutdown
tty: serial: samsung: simplify getting OF match data
tty: serial: samsung: constify variables and pointers
tty: serial: samsung: constify s3c24xx_serial_drv_data members
tty: serial: samsung: constify UART name
tty: serial: samsung: constify s3c24xx_serial_drv_data
tty: serial: samsung: reduce number of casts
tty: serial: samsung: embed s3c2410_uartcfg in parent structure
tty: serial: samsung: embed s3c24xx_uart_info in parent structure
serial: 8250_tegra: mark acpi_device_id as unused with !ACPI
tty: serial: bcm63xx: use more precise Kconfig symbol
serial: SERIAL_SUNPLUS should depend on ARCH_SUNPLUS
tty: serial: jsm: fix two assignments in if conditions
tty: serial: jsm: remove redundant assignments to variable linestatus
serial: 8250_mtk: make two read-only arrays static const
serial: samsung_tty: do not unlock port->lock for uart_write_wakeup()
...
Pull spi updates from Mark Brown:
"The overwhelming bulk of this pull request is a change from Uwe
Kleine-König which changes the return type of the remove() function to
void as part of some wider work he's doing to do this for all bus
types, causing updates to most SPI device drivers. The branch with
that on has been cross merged with a couple of other trees which added
new SPI drivers this cycle, I'm not expecting any build issues
resulting from the change.
Otherwise it's been a relatively quiet release with some new device
support, a few minor features and the welcome completion of the
conversion of the subsystem to use GPIO descriptors rather than
numbers:
- Change return type of remove() to void.
- Completion of the conversion of SPI controller drivers to use GPIO
descriptors rather than numbers.
- Quite a few DT schema conversions.
- Support for multiple SPI devices on a bus in ACPI systems.
- Big overhaul of the PXA2xx SPI driver.
- Support for AMD AMDI0062, Intel Raptor Lake, Mediatek MT7986 and
MT8186, nVidia Tegra210 and Tegra234, Renesas RZ/V2L, Tesla FSD and
Sunplus SP7021"
[ And this is obviously where that spi change that snuck into the
regulator tree _should_ have been :^]
* tag 'spi-v5.18' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi: (124 commits)
spi: fsi: Implement a timeout for polling status
spi: Fix erroneous sgs value with min_t()
spi: tegra20: Use of_device_get_match_data()
spi: mediatek: add ipm design support for MT7986
spi: Add compatible for MT7986
spi: sun4i: fix typos in comments
spi: mediatek: support tick_delay without enhance_timing
spi: Update clock-names property for arm pl022
spi: rockchip-sfc: fix platform_get_irq.cocci warning
spi: s3c64xx: Add spi port configuration for Tesla FSD SoC
spi: dt-bindings: samsung: Add fsd spi compatible
spi: topcliff-pch: Prevent usage of potentially stale DMA device
spi: tegra210-quad: combined sequence mode
spi: tegra210-quad: add acpi support
spi: npcm-fiu: Fix typo ("npxm")
spi: Fix Tegra QSPI example
spi: qup: replace spin_lock_irqsave by spin_lock in hard IRQ
spi: cadence: fix platform_get_irq.cocci warning
spi: Update NXP Flexspi maintainer details
dt-bindings: mfd: maxim,max77802: Convert to dtschema
...
We tested RS485 function on an EVB which has SC16IS752, after
finishing the test, we started the RS232 function test, but found the
RTS is still working in the RS485 mode.
That is because both startup and shutdown call port_update() to set
the EFCR_REG, this will not clear the RS485 bits once the bits are set
in the reconf_rs485(). To fix it, clear the RS485 bits in shutdown.
Cc: <stable@vger.kernel.org>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
Link: https://lore.kernel.org/r/20220308110042.108451-1-hui.wang@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Let serial core know that the chip automatically handles RTS/CTS signal.
This elimines completely unnecessary I2C/SPI bus traffic.
Cease reading from RX FIFO (by disabling RDI interrupt) when throttled.
Eventually the FIFO will fill up and the device will drive RTS output
inactive. Unthrottle by enabling back RDI interrupt.
Indirectly controlling RTS via RX FIFO state seems to be the only option
because RTS bit is ignored when hardware flow control is enabled.
Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com>
Link: https://lore.kernel.org/r/20220301060332.2561851-4-tomasz.mon@camlingroup.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sc16is7xx_stop_tx() clears THRI bit and thus disables THRI interrupt.
This makes it possible for transmission to cease indefinitely when more
than 64 characters are being sent.
The sc16is7xx_handle_tx() call executed by sc16is7xx_tx_proc() can send
up to FIFO length (64) characters. If more characters are written to the
output buffer, then the THRI interrupt is needed.
Solve the issue by enabling THRI interrupt in sc16is7xx_tx_proc().
Signed-off-by: Tomasz Moń <tomasz.mon@camlingroup.com>
Link: https://lore.kernel.org/r/20220301060332.2561851-2-tomasz.mon@camlingroup.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
A test was added to the probe function to ensure the device was
actually connected and working before successfully completing a
probe. If the device was actually there, but the I2C bus was not
ready yet for whatever reason, the probe fails permanently.
Change the probe so that we defer the probe on a regmap read
failure so that we try the probe again when the dependent drivers
are potentially loaded. This should not affect the case where the
device truly isn't present because the probe will never successfully
complete.
Fixes: 2aa916e67d ("sc16is7xx: Read the LSR register for basic device presence check")
Cc: stable@vger.kernel.org
Signed-off-by: Annaliese McDermond <nh6z@nh6z.net>
Link: https://lore.kernel.org/r/010101787f9c3fd8-c1815c00-2d6b-4c85-a96a-a13e68597fda-000000@us-west-2.amazonses.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some derivates of sc16is7xx devices expose more than one tty device to
userspace. If multiple such devices exist in a system, userspace
currently has no clean way to infer which tty maps to which physical
line.
Set the .iobase value to the relative index within the device to allow
infering the order through sysfs.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Link: https://lore.kernel.org/r/20200901120329.4176302-1-daniel@zonque.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.
Effectively no change.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Currently, the driver probes just fine and binds all its resources even
if the physical device is not present.
As the device lacks an identification register, let's at least read the
LSR register to check whether a device at the configured address responds
to the request at all.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Link: https://lore.kernel.org/r/20200521091152.404404-7-daniel@zonque.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the interrupt line is shared with other devices, the IRQ must be
level-triggered, as only one device can trigger a falling edge. To support
this, try to acquire the IRQ with IRQF_TRIGGER_LOW|IRQF_SHARED first.
Interrupt controllers that lack support for level-triggers will return an
error, in which case the driver will now retry the acqusition with
IRQF_TRIGGER_FALLING, which was also the default before.
Signed-off-by: Daniel Mack <daniel@zonque.org>
Link: https://lore.kernel.org/r/20200521091152.404404-6-daniel@zonque.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:
struct foo {
int stuff;
struct boo array[];
};
By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.
Also, notice that, dynamic memory allocations won't be affected by
this change:
"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]
This issue was found with the help of Coccinelle.
[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 7649773293 ("cxgb3/l2t: Fix undefined behaviour")
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Link: https://lore.kernel.org/r/20200213004611.GA8748@embeddedor.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
err_spi is only called within SERIAL_SC16IS7XX_SPI
while err_i2c is called inside SERIAL_SC16IS7XX_I2C.
So we need to put err_spi and err_i2c into each #ifdef
accordingly.
This change fixes ("sc16is7xx: move label 'err_spi'
to correct section").
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
err_spi is used when SERIAL_SC16IS7XX_SPI is enabled, so make
the label only available under SERIAL_SC16IS7XX_SPI option.
Otherwise, the below warning appears.
drivers/tty/serial/sc16is7xx.c:1523:1: warning: label ‘err_spi’ defined but not used [-Wunused-label]
err_spi:
^~~~~~~
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Fixes: ac0cdb3d99 ("sc16is7xx: missing unregister/delete driver on error in sc16is7xx_init()")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add the missing uart_unregister_driver() and i2c_del_driver() before return
from sc16is7xx_init() in the error handling case.
Signed-off-by: Mao Wenan <maowenan@huawei.com>
Reviewed-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
One of the more common cases of allocation size calculations is finding
the size of a structure that has a zero-sized array at the end, along
with memory for some number of elements for that array. For example:
struct foo {
int stuff;
void *entry[];
};
instance = devm_kzalloc(dev, sizeof(struct foo) + sizeof(void *) * count, GFP_KERNEL);
Instead of leaving these open-coded and prone to type mistakes, we can
now use the new struct_size() helper:
instance = devm_kzalloc(dev, struct_size(instance, entry, count), GFP_KERNEL);
This code was detected with the help of Coccinelle.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The SC16IS752 has an Enhanced Feature Register which is aliased at the
same address as the Interrupt Identification Register; accessing it
requires that a magic value is written to the Line Configuration
Register. If an interrupt is raised while the EFR is mapped in then
the ISR won't be able to access the IIR, leading to the "Unexpected
interrupt" error messages.
Avoid the problem by claiming a mutex around accesses to the EFR
register, also claiming the mutex in the interrupt handler work
item (this is equivalent to disabling interrupts to interlock against
a non-threaded interrupt handler).
See: https://github.com/raspberrypi/linux/issues/2529
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The SC16IS752 is a dual-channel device. The two channels are largely
independent, but the IRQ signals are wired together as an open-drain,
active low signal which will be driven low while either of the
channels requires attention, which can be for significant periods of
time until operations complete and the interrupt can be acknowledged.
In that respect it is should be treated as a true level-sensitive IRQ.
The kernel, however, needs to be able to exit interrupt context in
order to use I2C or SPI to access the device registers (which may
involve sleeping). Therefore the interrupt needs to be masked out or
paused in some way.
The usual way to manage sleeping from within an interrupt handler
is to use a threaded interrupt handler - a regular interrupt routine
does the minimum amount of work needed to triage the interrupt before
waking the interrupt service thread. If the threaded IRQ is marked as
IRQF_ONESHOT the kernel will automatically mask out the interrupt
until the thread runs to completion. The sc16is7xx driver used to
use a threaded IRQ, but a patch switched to using a kthread_worker
in order to set realtime priorities on the handler thread and for
other optimisations. The end result is non-threaded IRQ that
schedules some work then returns IRQ_HANDLED, making the kernel
think that all IRQ processing has completed.
The work-around to prevent a constant stream of interrupts is to
mark the interrupt as edge-sensitive rather than level-sensitive,
but interpreting an active-low source as a falling-edge source
requires care to prevent a total cessation of interrupts. Whereas
an edge-triggering source will generate a new edge for every interrupt
condition a level-triggering source will keep the signal at the
interrupting level until it no longer requires attention; in other
words, the host won't see another edge until all interrupt conditions
are cleared. It is therefore vital that the interrupt handler does not
exit with an outstanding interrupt condition, otherwise the kernel
will not receive another interrupt unless some other operation causes
the interrupt state on the device to be cleared.
The existing sc16is7xx driver has a very simple interrupt "thread"
(kthread_work job) that processes interrupts on each channel in turn
until there are no more. If both channels are active and the first
channel starts interrupting while the handler for the second channel
is running then it will not be detected and an IRQ stall ensues. This
could be handled easily if there was a shared IRQ status register, or
a convenient way to determine if the IRQ had been deasserted for any
length of time, but both appear to be lacking.
Avoid this problem (or at least make it much less likely to happen)
by reducing the granularity of per-channel interrupt processing
to one condition per iteration, only exiting the overall loop when
both channels are no longer interrupting.
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When the clock is enabled, check if there is an error. Otherwise
clk_get_rate() can be called without enabled clock.
Found by Linux Driver Verification project (linuxtesting.org).
Fixes: 0814e8d5da ("sc16is7xx: enable the clock")
Signed-off-by: Stefan Potyra <Stefan.Potyra@elektrobit.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
