The 8250 FIFOs indeed need to be cleared after stopping transmission in
RS485 mode without SER_RS485_RX_DURING_TX flag set. But there are two
problems with the approach taken by the previous patch from Fixes tag.
First, serial8250_clear_fifos() should clear fifos, but what it really
does is it enables the FIFOs unconditionally if present, clears them
and then sets the FCR register to zero, which effectively disables the
FIFOs. In case the FIFO is disabled, enabling it and clearing it makes
no sense and in fact can trigger misbehavior of the 8250 core. Moreover,
the FCR register may contain other FIFO configuration bits which may not
be writable unconditionally and writing them incorrectly can trigger
misbehavior of the 8250 core too. (ie. AM335x UART swallows the first
byte and retransmits the last byte twice because of this FCR write).
Second, serial8250_clear_and_reinit_fifos() completely reloads the FCR,
but what really has to happen at the end of the RS485 transmission is
clearing of the FIFOs and nothing else.
This patch repairs serial8250_clear_fifos() so that it really only
clears the FIFOs by operating on FCR[2:1] bits and leaves all the
other bits alone. It also undoes serial8250_clear_and_reinit_fifos()
from __do_stop_tx_rs485() as serial8250_clear_fifos() is sufficient.
Signed-off-by: Marek Vasut <marex@denx.de>
Fixes: 2bed8a8e70 ("Clearing FIFOs in RS485 emulation mode causes subsequent transmits to break")
Cc: Daniel Jedrychowski <avistel@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org> # let it bake a bit before merging
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Revert commit ecb988a3b7985913d1f0112f66667cdd15e40711: tty: serial:
8250: 8250_core: NXP SC16C2552 workaround
The above commit causes userland application to no longer write
correctly its first write to a dumb terminal connected to /dev/ttyS0.
This commit seems to be the culprit. It's as though the TX FIFO is being
reset during that write. What should be displayed is:
PSW 80000000 INST 00000000 HALT
//
What is displayed is some variation of:
T 00000000 HAL//
Reverting this commit via this patch fixes my problem.
Signed-off-by: Mark Hounschell <dmarkh@cfl.rr.com>
Fixes: ecb988a3b7 ("tty: serial: 8250: 8250_core: NXP SC16C2552 workaround")
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Since we have port name stored in struct uart_port, we better to use
that one instead of open coding.
This will make it one place source for easier maintenance or
modifications.
While here, replace printk_ratelimited(KERN_INFO ) by pr_info_ratelimited().
It seems last printk() call in 8250_port.c.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Some drivers could call serial8250_do_set_divisor() to complete its
own set_divisor routine. Export this symbol for code reusing.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add these two hooks so that they can be overridden with driver specific
implementations.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Align serial8250_get_divisor() with serial8250_set_divisor() to accept
uart_port pointer as the first parameter. No functionality changes.
Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Altera 16550 UART core supports FCR Rx Trigger Level setting,
but the port definition in the driver is missing the rxtrig_bytes
array specifying the trigger levels. Add the array to make the Rx
Trigger Level setting available on this type of 16550 UART.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, we export serial8250_rx_chars, which does a whole bunch of
reads from the 8250 data register, without any form of flow control
between reads.
An upcoming change to the aspeed vuart driver implements more
fine-grained flow control in the interrupt handler, requiring
character-at-a-time control over the rx path.
This change exports serial8250_read_char to allow this.
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Tested-by: Eddie James <eajames@linux.vnet.ibm.com>
Tested-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Nuvoton UART is almost compatible with the 8250 driver when probed
via the 8250_of driver, however it requires some extra configuration
at startup.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently, data in RX FIFO is read based on UART_LSR register state even
if RDI and RLSI interrupts are disabled in UART_IER register.
This is because when IRQ handler is called due to TX FIFO empty event,
RX FIFO is serviced based on UART_LSR register status instead of
UART_IIR status. This defeats the purpose of disabling UART RX
FIFO interrupts during throttling(see, omap_8250_throttle()) as IRQ
handler continues to drain UART RX FIFO resulting in overflow of buffer
at tty layer.
Fix this by making sure that driver drains UART RX FIFO only when
UART_IIR_RDI is set along with UART_LSR_BI or UART_LSR_DR bits.
Signed-off-by: Vignesh R <vigneshr@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Exar sleep wake-up handling has been done on a per-channel basis by
virtue of INT0 being accessible from each channel's address space. I
believe this was initially done out of necessity, but now that Exar
devices have their own driver, we can do things more efficiently by
registering a dedicated INT0 handler at the PCI device level.
I see this change providing the following benefits:
1. If more than one port is active, eliminates the redundant bus
cycles for reading INT0 on every interrupt.
2. This note associated with hooking in the per-channel handler in
8250_port.c is resolved:
/* Fixme: probably not the best place for this */
Cc: Matt Schulte <matts@commtech-fastcom.com>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that the SPDX tag is in all tty files, that identifies the license
in a specific and legally-defined manner. So the extra GPL text wording
can be removed as it is no longer needed at all.
This is done on a quest to remove the 700+ different ways that files in
the kernel describe the GPL license text. And there's unneeded stuff
like the address (sometimes incorrect) for the FSF which is never
needed.
No copyright headers or other non-license-description text was removed.
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.
Update the drivers/tty files files with the correct SPDX license
identifier based on the license text in the file itself. The SPDX
identifier is a legally binding shorthand, which can be used instead of
the full boiler plate text.
This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Jiri Kosina <jikos@kernel.org>
Cc: David Sterba <dsterba@suse.com>
Cc: James Hogan <jhogan@kernel.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Eric Anholt <eric@anholt.net>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Ray Jui <rjui@broadcom.com>
Cc: Scott Branden <sbranden@broadcom.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Helge Deller <deller@gmx.de>
Cc: Joachim Eastwood <manabian@gmail.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Tobias Klauser <tklauser@distanz.ch>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Richard Genoud <richard.genoud@gmail.com>
Cc: Alexander Shiyan <shc_work@mail.ru>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: "Maciej W. Rozycki" <macro@linux-mips.org>
Cc: "Uwe Kleine-König" <kernel@pengutronix.de>
Cc: Pat Gefre <pfg@sgi.com>
Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Carlo Caione <carlo@caione.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Sudeep Holla <sudeep.holla@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Andy Gross <andy.gross@linaro.org>
Cc: David Brown <david.brown@linaro.org>
Cc: "Andreas Färber" <afaerber@suse.de>
Cc: Kevin Cernekee <cernekee@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Timur Tabi <timur@tabi.org>
Cc: Tony Prisk <linux@prisktech.co.nz>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Canceling hrtimer when holding uart spinlock can deadlock.
CPU0: syscall write
-> get uart port spinlock
-> write uart
-> start_tx_rs485
-> hrtimer_cancel
-> wait for hrtimer callback to finish
CPU1: hrtimer IRQ
-> run hrtimer
-> em485_handle_stop_tx
-> get uart port spinlock
CPU0 is waiting for the hrtimer callback to finish, but the hrtimer
callback running on CPU1 is waiting to get the uart port spinlock.
This deadlock can be avoided by not canceling the hrtimers in these paths.
Setting active_timer=NULL can be done without accessing hrtimer,
and that will effectively cancel operations that would otherwise have been
performed by the hrtimer callback.
Signed-off-by: Tomas Melin <tomas.melin@vaisala.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The upper four bits of the XR17V35x fractional divisor register (DLD)
control general chip function (RS-485 direction pin polarity, multidrop
mode, XON/XOFF parity check, and fast IR mode). Don't allow these bits
to be clobbered when setting the baudrate.
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add a define for the maximum baud rate divisor, to improve code
readability.
Signed-off-by: Ed Blake <ed.blake@sondrel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After switching to HR timers for RS485 the NULL checks for the object
inside timer functions become useless.
Remove them to avoid confusion to static analyzers.
Fixes 6e0a5de213 ("serial: 8250: Use hrtimers for rs485 delays")
Cc: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
MediaTek BTIF controller is the serial interface similar to UART but it
works only as the digital device which is mainly used to communicate with
the connectivity module called CONNSYS inside the SoC which could be mostly
found on those MediaTek SoCs with Bluetooth feature such as MT7622 and
MT7623 SoCs.
And the controller is made as being compatible with the 8250 register
layout with extra registers such as DMA enablement so it tends to be
integrated with reusing 8250 OF driver. However, DMA mode is not being
supported yet in the current driver.
Signed-off-by: Sean Wang <sean.wang@mediatek.com>
Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Previously the timers where based on the classic timers, giving a too
coarse resolution on systems with configs of less than 1000 HZ.
This patch changes the rs485 timers to hrtimers.
Signed-off-by: Rafael Gago Castano <rgc@hms.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
First 16 bits in the flags field are user-visible except
UPF_NO_TXEN_TEST. To keep it clean we introduce internal quirks and move
UPF_NO_TXEN_TEST to them. Rename the constant to UPQ_NO_TXEN_TEST to
distinguish with port flags. Users are converted accordingly.
The quirks field might be extended later to hold the additional ones.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The BCM2835 MINI UART has non-standard THRE semantics. Conventionally
the bit means that the FIFO is empty (although there may still be a
byte in the transmit register), but on 2835 it indicates that the FIFO
is not full. This causes interrupts after every byte is transmitted,
with the FIFO providing some interrupt latency tolerance.
A consequence of this difference is that the usual strategy of writing
multiple bytes into the TX FIFO after checking THRE once is unsafe.
In the worst case of 7 bytes in the FIFO, writing 8 bytes loses all
but the first since by then the FIFO is full.
There is an HFIFO ("Hidden FIFO") capability that causes the transmit
loop to terminate when both THRE and TEMT are set, i.e. when the TX
block is completely idle. This is unnecessarily cautious, potentially
causing gaps in transmission.
Add a new conditional to the transmit loop, predicated on CAP_MINI,
that exits when THRE is no longer set (the FIFO is full). This allows
the FIFO to fill quickly but subsequent writes are paced by the
transmission rate.
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Acked-by: Eric Anholt <eric@anholt.net>
Acked-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The AUX/mini-UART in the BCM2835 family of procesors is a cut-down
8250 clone. In particular it is lacking support for the following
features: CSTOPB PARENB PARODD CMSPAR CS5 CS6
Add a new capability (UART_CAP_MINI) that exposes the restrictions to
the user of the termios API by turning off the unsupported features in
the request.
N.B. It is almost possible to automatically discover the missing
features by reading back the LCR register, but the CSIZE bits don't
cooperate (contrary to the documentation, both bits are significant,
but CS5 and CS6 are mapped to CS7) and the code is much longer.
See: https://github.com/raspberrypi/linux/issues/1561
Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
After migrating 8250_exar to MSI in 172c33cb61, we can get stuck
without further interrupts because of the special wake-up event these
chips send. They are only cleared by reading INT0. As we fail to do so
during startup and shutdown, we can leave the interrupt line asserted,
which is fatal with edge-triggered MSIs.
Add the required reading of INT0 to startup and shutdown. Also account
for the fact that a pending wake-up interrupt means we have to return 1
from exar_handle_irq. Drop the unneeded reading of INT1..3 along with
this - those never reset anything.
An alternative approach would have been disabling the wake-up interrupt.
Unfortunately, this feature (REGB[17] = 1) is not available on the
XR17D15X.
Fixes: 172c33cb61 ("serial: exar: Enable MSI support")
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit fa01e2ca9f ("serial: 8250: Integrate Fintek into 8250_base")
modified the probing logic for PNP0501 devices, to remove a collision
between the generic 16550A driver and the Fintek driver, which reused
the same ACPI _HID.
The Fintek device probe is now incorporated into the common 8250 probe
path, and gets called for all discovered 16550A compatible devices,
including ones that are MMIO mapped rather than IO mapped. However,
the Fintek driver assumes the port base is a I/O address, and proceeds
to probe some arbitrary offsets above it.
This is generally a wrong thing to do, but on ARM systems (having no
native port I/O), this may result in faulting accesses of completely
unrelated MMIO regions in the PCI I/O space. Given that this is at
serial probe time, this results in hard to diagnose crashes at boot.
So let's restrict the Fintek probe to devices that we know are using
port I/O in the first place.
Fixes: fa01e2ca9f ("serial: 8250: Integrate Fintek into 8250_base")
Suggested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Ricardo Ribalda <ricardo.ribalda@gmail.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The probing of THRE irq behaviour assumes the other end will be reading
bytes out of the buffer in order to probe the port at driver init. In
some cases the other end cannot be relied upon to read these bytes, so
provide a flag for them to skip this step.
Bit 19 was chosen as the flags are a int and the top bits are taken.
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Define an OF early console for Palmchip UART, which can be enabled
by passing "earlycon" on the boot command line.
Signed-off-by: Marc Gonzalez <marc_gonzalez@sigmadesigns.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
None of these registers is relevant for the userspace API.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This adds a new UART port type for TI DA8xx/OMAPL13x/AM17xx/AM18xx/66AK2x.
These SoCs have standard 8250 registers plus some extra non-standard
registers.
The UART will not function unless the non-standard Power and Emulation
Management Register (PWREMU_MGMT) is configured correctly. This is
currently handled in arch/arm/mach-davinci/serial.c for non-device-tree
boards. Making this part of the UART driver will allow UART to work on
device-tree boards as well and the mach code can eventually be removed.
Signed-off-by: David Lechner <david@lechnology.com>
Acked-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
With CONFIG_DYNAMIC_DEBUG if dyndbg enables debug output in
8250_port.c deadlock happens inevitably on UART IRQ handling.
That's the problematic execution path:
---------------------------->8------------------------
UART IRQ:
serial8250_interrupt() ->
serial8250_handle_irq(): lock "port->lock" ->
pr_debug() ->
serial8250_console_write(): bump in locked "port->lock".
OR (if above pr_debug() gets removed):
serial8250_tx_chars() ->
pr_debug() ->
serial8250_console_write(): bump in locked "port->lock".
---------------------------->8------------------------
So let's get rid of those not that much useful debug entries.
Discussed problem could be easily reproduced with QEMU for x86_64.
As well as this fix could be mimicked with muting of dynamic debug for
the problematic lines as simple as:
---------------------------->8------------------------
dyndbg="+p; file 8250_port.c line 1756 -p; file 8250_port.c line 1822 -p"
---------------------------->8------------------------
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Phillip Raffeck <phillip.raffeck@fau.de>
Cc: Anton Wuerfel <anton.wuerfel@fau.de>
Cc: "Matwey V. Kornilov" <matwey@sai.msu.ru>
Cc: Yegor Yefremov <yegorslists@googlemail.com>
Cc: Thor Thayer <tthayer@opensource.altera.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When in RS485 emulation mode, __do_stop_tx_rs485() calls
serial8250_clear_fifos(). This not only clears the FIFOs, but also sets
all bits in their control register (UART_FCR) to 0.
One of the effects of this is the disabling of the FIFOs, which turns
them into single-byte holding registers. The rest of the driver doesn't
know this, which results in the lions share of characters passed into a
write call to be dropped.
(I can supply logic analyzer screenshots if necessary)
This fix replaces the serial8250_clear_fifos() call to
serial8250_clear_and_reinit_fifos() - this prevents the "dropped
characters" issue from manifesting again while retaining the requirement
of clearing the RX FIFO after transmission if the SER_RS485_RX_DURING_TX
flag is disabled.
Signed-off-by: Daniel Jedrychowski <avistel@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Expose set_ldisc() function so that it can be overridden with a
platform specific implementation.
Signed-off-by: Ed Blake <ed.blake@imgtec.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The following fix of runtime PM use in DMA mode requires at least
serial8250_rpm_put_tx() to be available. Export both calls.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
NXP SC16C2552 requires that we always write a reset to the RX FIFO and
TX FIFO whenever we enable the FIFOs
Cc: xe-kernel@external.cisco.com
Signed-off-by: Steve Shih <sshih@cisco.com>
Signed-off-by: David Singleton <davsingl@cisco.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The Altera 16550 soft IP UART requires 2 additional registers for
TX FIFO threshold support. These 2 registers enable the TX FIFO
Low Watermark and set the TX FIFO Low Watermark.
Set the TX FIFO threshold to the FIFO size - tx_loadsz.
Signed-off-by: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Unify the check of em485 variable to be either (em485) or (!em485) instead of
the explicit comparison to NULL.
While here, remove redundant check in __do_stop_tx_rs485() and
__stop_tx_rs485() since the functions ain't called with NULL value of em485
variable.
Cc: "Matwey V. Kornilov" <matwey@sai.msu.ru>
Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There are calls to serial8250_rpm_{get|put}() in __do_stop_tx_rs485() that are
certainly placed in a wrong location. I dunno how it had been tested with
runtime PM enabled because it is obvious "sleep in atomic context" error.
Besides that serial8250_rpm_get() is called immediately after an IO just
happened. It implies that the device is already powered on, see implementation
of serial8250_em485_rts_after_send() and serial8250_clear_fifos() for the
details.
There is no bug have been seen due to, as I can guess, use of auto suspend mode
when scheduled transaction to suspend is invoked quite lately than it's needed
for a few writes to the port. It might be possible to trigger a warning if
stop_tx_timer fires when device is suspended.
Refactor the code to use runtime PM only in case of timer function.
Fixes: 0c66940d58 ("tty/serial/8250: fix RS485 half-duplex RX")
Cc: "Matwey V. Kornilov" <matwey@sai.msu.ru>
Tested-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Intel Quark has 16550A compatible UART with autoflow feature enabled. It has
only 16 bytes of FIFO. Currently serial8250_do_set_termios() prevents to enable
autoflow since the minimum requirement of 32 bytes of FIFO size.
Drop a FIFO size limitation to allow autoflow control be enabled on such UARTs.
While here, comment out UART_CAP_AFE for PORT_AR7 since it wasn't working and
it will be not a good idea to use it in conjunction with trigger level of 1
byte.
Suggested-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mediatek can support baud rate up to 4M.
the 'uart_get_baud_rate' function will limit the max baud rate.
Modify max baud to remove the limit.
Signed-off-by: Long Cheng <long.cheng@mediatek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Serial console is broken in v4.8-rcX. Mika and I independently bisected down to
commit 4ef03d3287 ("tty/serial/8250: use mctrl_gpio helpers").
Since neither author nor anyone else didn't propose a solution we better revert
it for now.
This reverts commit 4ef03d3287.
Link: https://lkml.kernel.org/r/20160809130229.GN1729@lahna.fi.intel.com
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Tested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This patch permits the usage for GPIOs to control
the CTS/RTS/DTR/DSR/DCD/RI signals.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Introduce serial8250_out_MCR() and serial8250_in_MCR() routines, that
replace following calls:
serial_out(port, UART_MCR, val)
serial_port_out(up, UART_MCR, val)
serial_in(port, UART_MCR)
This patch is needed in order to integrate reading/writing of MCR
signals via SERIAL_MCTRL_GPIO infrastructure later.
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The compiler complains about variables that are set, but never used:
* intX variables in exar_handle_irq
drivers/tty/serial/8250/8250_port.c:1864:34: warning: variable ‘int3’ set but not used [-Wunused-but-set-variable]
* val variable in pci_quatech_wqopr
drivers/tty/serial/8250/8250_pci.c:1139:10: warning: variable ‘val’ set but not used [-Wunused-but-set-variable]
And about a shadow variable:
* tmout in wait_for_xmitr is defined twice with the same type. Both of
them are also initialized before use.
Remove all of them.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Matt Schulte <matts@commtech-fastcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert DEBUG_INTR to pr_debug:
* defined semantics (DEBUG, DYNAMIC_DEBUG)
* KERN_DEBUG level instead of KERN_DEFAULT
* emit __func__ and \n
* verified 'fmt' even when !DEBUG
I wonder if anybody ever used that or whether we should just drop the
lines.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The 8250_fintek driver advertises as the PNP0501 driver; however this
conflicts with the standard 16550A uart PNP0501. The conflict causes
the 8250_fintek driver to load with _every_ PNP0501, but never probe,
and causing the entire 8250 driver stack to unload if the 8250_fintek
driver is unloaded (modprobe doesn't know that 8250_pnp rather than
8250_fintek claimed the resource).
This patch merges the Fintek driver into 8250_base. On autoconfig_16550
the device is probed to verify if it is a FINTEK device or not.
This custom probing can be disabled completely via configuration. When a
Fintek device is not probed it will behave as a standard 16550A device,
with no RS485 capabilities.
Reported-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Using fake IIR values to perform rx dma operations unnecessarily
conflates separate operations, stopping in-progress dma with starting
new dma.
Introduce serial8250_rx_dma_flush() to handle stopping in-progress dma
[omap8250 already has equivalent omap_8250_rx_dma_flush()].
Replace rx_dma(UART_IIR_RX_TIMEOUT) with the equivalent *_rx_dma_flush(),
and rx_dma(0) with the equivalent *_rx_dma(). Handle IIR steering
in the irq handler with handle_rx_dma() helper.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If !up->dma == F, then up->dma == T and can be elided from the
(up->dma && up->dma->tx_err) sub-expression.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Marek Vasut