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In the conversion to generic early console, the passing of options from
the early 8250 console to the regular ttyS console was broken. This
resulted in the baud rate changing when switching consoles during boot.
This feature allows specifying a single console option on the kernel
command line rather than both an early console and regular serial tty
console. It would be nice to generalize this feature. However, it only
works if the correct baud rate can be probed early which is not the
case on many platforms which have non-standard UART clock rates. So for
now, this is left as an 8250 specific feature.
Reported-and-tested-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If IGNBRK is set without either BRKINT or PARMRK set, some uart
drivers send a 0x00 byte for BREAK without the TTYBREAK flag to the
line discipline, when it should send either nothing or the TTYBREAK flag
set. This happens because the read_status_mask masks out the BI
condition, which uart_insert_char() then interprets as a normal 0x00 byte.
SUS v3 is clear regarding the meaning of IGNBRK; Section 11.2.2, General
Terminal Interface - Input Modes, states:
"If IGNBRK is set, a break condition detected on input shall be ignored;
that is, not put on the input queue and therefore not read by any
process."
Fix read_status_mask to include the BI bit if IGNBRK is set; the
lsr status retains the BI bit if a BREAK is recv'd, which is
subsequently ignored in uart_insert_char() when masked with the
ignore_status_mask.
Affected drivers:
8250 - all
serial_txx9
mfd
amba-pl010
amba-pl011
atmel_serial
bfin_uart
dz
ip22zilog
max310x
mxs-auart
netx-serial
pnx8xxx_uart
pxa
sb1250-duart
sccnxp
serial_ks8695
sirfsoc_uart
st-asc
vr41xx_siu
zs
sunzilog
fsl_lpuart
sunsab
ucc_uart
bcm63xx_uart
sunsu
efm32-uart
pmac_zilog
mpsc
msm_serial
m32r_sio
Unaffected drivers:
omap-serial
rp2
sa1100
imx
icom
Annotated for fixes:
altera_uart
mcf
Drivers without break detection:
21285
xilinx-uartps
altera_jtaguart
apbuart
arc-uart
clps711x
max3100
uartlite
msm_serial_hs
nwpserial
lantiq
vt8500_serial
Unknown:
samsung
mpc52xx_uart
bfin_sport_uart
cpm_uart/core
Fixes: Bugzilla #71651, '8250_core.c incorrectly handles IGNBRK flag'
Reported-by: Ivan <athlon_@mail.ru>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty into next
Pull tty/serial driver updates from Greg KH:
"Here is the big tty / serial driver pull request for 3.16-rc1.
A variety of different serial driver fixes and updates and additions,
nothing huge, and no real major core tty changes at all.
All have been in linux-next for a while"
* tag 'tty-3.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (84 commits)
Revert "serial: imx: remove the DMA wait queue"
serial: kgdb_nmi: Improve console integration with KDB I/O
serial: kgdb_nmi: Switch from tasklets to real timers
serial: kgdb_nmi: Use container_of() to locate private data
serial: cpm_uart: No LF conversion in put_poll_char()
serial: sirf: Fix compilation failure
console: Remove superfluous readonly check
console: Use explicit pointer type for vc_uni_pagedir* fields
vgacon: Fix & cleanup refcounting
ARM: tty: Move HVC DCC assembly to arch/arm
tty/hvc/hvc_console: Fix wakeup of HVC thread on hvc_kick()
drivers/tty/n_hdlc.c: replace kmalloc/memset by kzalloc
vt: emulate 8- and 24-bit colour codes.
printk/of_serial: fix serial console cessation part way through boot.
serial: 8250_dma: check the result of TX buffer mapping
serial: uart: add hw flow control support configuration
tty/serial: at91: add interrupts for modem control lines
tty/serial: at91: use mctrl_gpio helpers
tty/serial: Add GPIOLIB helpers for controlling modem lines
ARM: at91: gpio: implement get_direction
...
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Using dma_mapping_error() to make sure the mapping did not
fail.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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8250 uart driver currently supports only software assisted hw flow
control. The software assisted hw flow control maintains a hw_stopped
flag in the tty structure to stop and start transmission and use modem
status interrupt for the event to drive the handshake signals. This is
not needed if hw has flow control capabilities. This patch adds a
DT attribute for enabling hw flow control for a uart port. Also skip
stop and start if this flag is present in flag field of the port
structure.
Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
CC: Rob Herring <robh+dt@kernel.org>
CC: Pawel Moll <pawel.moll@arm.com>
CC: Mark Rutland <mark.rutland@arm.com>
CC: Ian Campbell <ijc+devicetree@hellion.org.uk>
CC: Kumar Gala <galak@codeaurora.org>
CC: Randy Dunlap <rdunlap@infradead.org>
CC: Jiri Slaby <jslaby@suse.cz>
CC: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add support for Advantech PCM-3614I/PCM-3618I serial expansion cards
Advantech makes a variety of serial port expansion cards, including the
PCM-3614 and PCM-3618
(http://www.advantech.com/products/1-2JKLU5/PCM-3618/mod_5DF8DE5A-6B49-4429-BB2F-CB35FE1D168D.aspx).
They have a driver available which was forked from the kernel driver
ages ago and has not been maintained in quite some time, available at
http://support.advantech.com.tw/Support/DownloadSRDetail_New.aspx?SR_ID=1-1W8FZ5&Doc_Source=Download
Their driver added several features to aid in communications at higher
baud rates, but at normal serial port speeds, the standard 8250_pci
driver functions just fine. This patch adds the necessary PCI IDs to
recognize this card.
See bug 75681 (https://bugzilla.kernel.org/show_bug.cgi?id=75681)
Signed-off-by: Thomee Wright <TWright@TMCDesign.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This Multi-IO card has one serial 16550-like and one parallel port connector.
Here's the lspci output, after this commit is applied:
03:07.0 Serial controller: Device 4348:5053 (rev 10) (prog-if 02 [16550])
Subsystem: Device 4348:5053
Control: I/O+ Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap- 66MHz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Interrupt: pin A routed to IRQ 21
Region 0: I/O ports at cf00 [size=8]
Region 1: I/O ports at ce00 [size=8]
Kernel driver in use: parport_serial
Kernel modules: 8250_pci, parport_serial
This commit adds an entry with the device ID to the blacklist declared in
8250_pci to prevent the driver from taking ownership. Also, and as was done
for the 2S/1P variant, add a quirk to skip autodetection and set the correct
type to 16550A clone.
Proper entries are added to parport_serial, to support the device parallel
and serial ports.
Cc: Gianluca Anzolin <gianluca@sottospazio.it>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit d2fd6810a823bcd (tty/serial: convert 8250 to generic earlycon)
removed setup_early_serial8250_console, but there are still 2 callers
in:
arch/mips/mti-malta/malta-init.c
drivers/firmware/pcdp.c
Add back the function implemented as a wrapper to setup_earlycon.
Reported-by: Yinghai Lu <yinghai@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The sleep function was updated to put the serial port to sleep only when necessary.
This appears to resolve the errant behavior of the driver as described in
Kernel Bug 61961 – "My Exar Corp. XR17C/D152 Dual PCI UART modem does not
work with 3.8.0".
Signed-off-by: Michael Welling <mwelling@ieee.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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With the generic earlycon infrastructure in place, convert the 8250
early console to use it.
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In preparation to support FIX_EARLYCON_MEM on other arches, make the
option per arch.
Signed-off-by: Rob Herring <robh@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In (efe2f29 kgdboc,kdb: Allow kdb to work on a non open console port)
support was added to directly use the "write_char" functions when
doing kdb over a non-open console port. This is great, but it ends up
bypassing the normal code in uart_console_write() that adds a carriage
return before any newlines.
There appears to have been a trend to add this support directly in
some console driver's poll_put_char() functions. This had a few side
effects, including:
- In this case we were doing LFCR, not CRLF. This was fixed in
uart_console_write() back in (d358788 [SERIAL] kernel console should
send CRLF not LFCR)
- Not all serial drivers had the LFCR code in their poll_put_char()
functions. In my case I was running serial/samsung.c which lacked
it.
I've moved the handling to uart_poll_put_char() to fix the above
problems. Now when I use kdb (and don't point console= to the same
UART) I no longer get:
[0]kdb>
[0]kdb>
[0]kdb>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In the same manner as 8250_pci, 8250_dw needs some
baytrail specific quirks to be used. The reference
clock needs to be adjusted before divided in order
to have the minimum error rate on the baudrate.
The specific byt set termios function is stored in
the driver_data field of the acpi device id via the
dw8250_acpi_desc structure.
Remove the uartclk field which is no longer delivered
as driver data.
Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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__dma_tx_complete is not protected against concurrent
call of serial8250_tx_dma. it can lead to circular tail
index corruption or parallel call of serial_tx_dma on the
same data portion.
This patch fixes this issue by holding the port lock.
Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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On transmit-hold-register empty, serial8250_tx_chars
should be called only if we don't use DMA.
DMA has its own tx cycle.
Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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In -RT the spin_lock_irqsave() does not spin but sleep if the lock is
taken. Before that, local_irq_save() is invoked which disables
interrupts even on -RT. Therefore local_irq_save() + spin_lock() does not
work.
In the ->sysrq and oops_in_progress case it is save to trylock the lock
i.e. this is what we do now anyway except for ->sysrq where we assume
that the lock is already taken.
The spin_lock_irqsave() grabs the lock and disables the interrupts on
vanilla (the same behavior) and on -RT it won't disable interrupts.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
[bigeasy: add a patch description]
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The Intel BayTrail HSUART power-on default reference clock is 44.2368 MHz,
but 73.728 MHz provides 0% error for additional "conventional" baud rates
above 460800 (e.g. 576000, 921600, and 1152000).
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Support the following additional baud rates with 0% error:
500000, 1500000, 2500000, 3500000
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Every couple of months, someone sends a patch to fix:
drivers/tty/serial/8250/8250_core.c: In function 'serial_unlink_irq_chain':
drivers/tty/serial/8250/8250_core.c:1712:2: warning: 'i' may be used uninitialized in this function [-Wuninitialized]
and they in turn get a NACK for their efforts, and are told that
their compiler is broken. This has been going on since at least
the year 2008: https://lkml.org/lkml/2008/11/24/433
Lets add a comment, so that subsequent patches don't get as far as
the maintainers or the mailing lists.
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The Exar XR17V35x family of UARTs have an additional fractional divisor
register (DLD) which was not being used. Calculate and set this
register for these devices to reduce their baud rate error.
Signed-off-by: Joe Schultz <jschultz@xes-inc.com>
Signed-off-by: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Aparently 9865 uses standard BAR encoding scheme (unlike 99xx cards).
Current pci_netmos_9900_setup() uses wrong BAR indices for the 9865 PCI
device, function 2. Using standard BAR indices makes all 6 ports work
for me. Thus disable the NetMos 9900 quirk for NetMos 9865 pci device.
For the reference, here is the relevant part of lspci for my device:
02:07.0 Serial controller: MosChip Semiconductor Technology Ltd. PCI
9865 Multi-I/O Controller (prog-if 02 [16550])
Subsystem: Device a000:1000
Flags: bus master, medium devsel, latency 32, IRQ 17
I/O ports at ac00 [size=8]
Memory at fcfff000 (32-bit, non-prefetchable) [size=4K]
Memory at fcffe000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [48] Power Management version 2
Kernel driver in use: serial
02:07.1 Serial controller: MosChip Semiconductor Technology Ltd. PCI
9865 Multi-I/O Controller (prog-if 02 [16550])
Subsystem: Device a000:1000
Flags: bus master, medium devsel, latency 32, IRQ 18
I/O ports at a800 [size=8]
Memory at fcffd000 (32-bit, non-prefetchable) [size=4K]
Memory at fcffc000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [48] Power Management version 2
Kernel driver in use: serial
02:07.2 Communication controller: MosChip Semiconductor Technology Ltd.
PCI 9865 Multi-I/O Controller
Subsystem: Device a000:3004
Flags: bus master, medium devsel, latency 32, IRQ 19
I/O ports at a400 [size=8]
I/O ports at a000 [size=8]
I/O ports at 9c00 [size=8]
I/O ports at 9800 [size=8]
Memory at fcffb000 (32-bit, non-prefetchable) [size=4K]
Capabilities: [48] Power Management version 2
Kernel driver in use: serial
Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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CONFIG_PM will be set if either or both CONFIG_PM_SLEEP and
CONFIG_PM_RUNTIME is set. Compiling the driver with !CONFIG_PM_SLEEP causes
following compilation warnings:
drivers/tty/serial/8250/8250_dw.c:404:12: warning: ‘dw8250_suspend’ defined but not used [-Wunused-function]
drivers/tty/serial/8250/8250_dw.c:413:12: warning: ‘dw8250_resume’ defined but not used [-Wunused-function]
Fix this by using CONFIG_PM_SLEEP instead.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Tegra chips have 4 or 5 identical UART modules embedded. UARTs C..E have
their MODEM-control signals tied off to a static state. However UARTs A
and B can optionally route those signals to/from package pins, depending
on the exact pinmux configuration.
When these signals are not routed to package pins, false interrupts may
trigger either temporarily, or permanently, all while not showing up in
the IIR; it will read as NO_INT. This will eventually lead to the UART
IRQ being disabled due to unhandled interrupts. When this happens, the
kernel may print e.g.:
irq 68: nobody cared (try booting with the "irqpoll" option)
In order to prevent this, enable UART_BUG_NOMSR. This prevents
UART_IER_MSI from being enabled, which prevents the false interrupts
from triggering.
In practice, this is not needed under any of the following conditions:
* On Tegra chips after Tegra30, since the HW bug has apparently been
fixed.
* On UARTs C..E since their MODEM control signals are tied to the correct
static state which doesn't trigger the issue.
* On UARTs A..B if the MODEM control signals are routed out to package
pins, since they will then carry valid signals.
However, we ignore these exceptions for now, since they are only relevant
if a board actually hooks up more than a 4-wire UART, and no currently
supported board does this. If we ever support a board that does, we can
refine the algorithm that enables UART_BUG_NOMSR to take those exceptions
into account, and/or read a flag from DT/... that indicates that the
board has hooked up and pinmux'd more than a 4-wire UART.
Reported-by: Olof Johansson <olof@lixom.net> # autotester
Cc: <stable@vger.kernel.org>
Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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None of these files are actually using any __init type directives
and hence don't need to include <linux/init.h>. Most are just a
left over from __devinit and __cpuinit removal, or simply due to
code getting copied from one driver to the next.
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need the tty fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fix the initialisation of older Quatech serial cards which are fitted with
the AMCC PCI Matchmaker interface chip.
Signed-off-by: Jonathan Woithe (jwoithe@just42.net)
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Newer Intel PCHs with LPSS have the same Designware controllers than
Haswell but ACPI IDs are different. Add these IDs to the driver list.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit c49436b657d0 (serial: 8250_dw: Improve unwritable LCR workaround)
caused a regression. It added a check that the LCR was written properly
to detect and workaround the busy quirk, but the behaviour of bit 5
(UART_LCR_SPAR) differs between IP versions 3.00a and 3.14c per the
docs. On older versions this caused the check to fail and it would
repeatedly force idle and rewrite the LCR register, causing delays and
preventing any input from serial being received.
This is fixed by masking out UART_LCR_SPAR before making the comparison.
Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Tim Kryger <tim.kryger@linaro.org>
Cc: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Cc: Matt Porter <matt.porter@linaro.org>
Cc: Markus Mayer <markus.mayer@linaro.org>
Tested-by: Tim Kryger <tim.kryger@linaro.org>
Tested-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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ACPI now provides stubs for the functions the driver uses.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Commit 9326b047e4fd4a8da72e59d913214a1803e9709c includes a typo
of "8350_core" instead of "8250_core", so correct it.
Fixes kernel bugzilla #60724:
https://bugzilla.kernel.org/show_bug.cgi?id=60724
Reported-by: Christoph Biedl <bugzilla.kernel.bpeb@manchmal.in-ulm.de>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Chip PI7C9X7952/4/8
Signed-off-by: Angelo Butti <buttiangelo@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This adds support for Fintek's 4, 8, and 12 port PCIE serial cards.
Thanks to Fintek for the sample devices, and the spec needed in order to
implement this.
Cc: Amanda Ying <amanda_ying@fintek.com.tw>
Cc: Felix Shih <felix_shih@fintek.com.tw>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Add calls to clk_prepare and unprepare so that EMMA Mobile EV2 can
migrate to the common clock framework.
Signed-off-by: Shinya Kuribayashi <shinya.kuribayashi.px@renesas.com>
[takashi.yoshii.ze@renesas.com: edited for conflicts]
Signed-off-by: Takashi Yoshii <takashi.yoshii.zj@renesas.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Magnus Damm <damm@opensource.se>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When configured with UART_16550_COMPATIBLE=NO or in versions prior to
the introduction of this option, the Designware UART will ignore writes
to the LCR if the UART is busy. The current workaround saves a copy of
the last written LCR and re-writes it in the ISR for a special interrupt
that is raised when a write was ignored.
Unfortunately, interrupts are typically disabled prior to performing a
sequence of register writes that include the LCR so the point at which
the retry occurs is too late. An example is serial8250_do_set_termios()
where an ignored LCR write results in the baud divisor not being set and
instead a garbage character is sent out the transmitter.
Furthermore, since serial_port_out() offers no way to indicate failure,
a serious effort must be made to ensure that the LCR is actually updated
before returning back to the caller. This is difficult, however, as a
UART that was busy during the first attempt is likely to still be busy
when a subsequent attempt is made unless some extra action is taken.
This updated workaround reads back the LCR after each write to confirm
that the new value was accepted by the hardware. Should the hardware
ignore a write, the TX/RX FIFOs are cleared and the receive buffer read
before attempting to rewrite the LCR out of the hope that doing so will
force the UART into an idle state. While this may seem unnecessarily
aggressive, writes to the LCR are used to change the baud rate, parity,
stop bit, or data length so the data that may be lost is likely not
important. Admittedly, this is far from ideal but it seems to be the
best that can be done given the hardware limitations.
Lastly, the revised workaround doesn't touch the LCR in the ISR, so it
avoids the possibility of a "serial8250: too much work for irq" lock up.
This problem is rare in real situations but can be reproduced easily by
wiring up two UARTs and running the following commands.
# stty -F /dev/ttyS1 echo
# stty -F /dev/ttyS2 echo
# cat /dev/ttyS1 &
[1] 375
# echo asdf > /dev/ttyS1
asdf
[ 27.700000] serial8250: too much work for irq96
[ 27.700000] serial8250: too much work for irq96
[ 27.710000] serial8250: too much work for irq96
[ 27.710000] serial8250: too much work for irq96
[ 27.720000] serial8250: too much work for irq96
[ 27.720000] serial8250: too much work for irq96
[ 27.730000] serial8250: too much work for irq96
[ 27.730000] serial8250: too much work for irq96
[ 27.740000] serial8250: too much work for irq96
Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Move the printk() calls to to dev_*() instead, to tie into the dynamic
debugging infrastructure.
Also change some "raw" printk() calls to dev_err() to provide a better
error message to userspace so it can properly identify the device and
not just have to guess.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The stub for dw8250_probe_acpi() is missing an argument.
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Intel BayTrail has two HS-UARTs with 64 byte fifo, support
for DMA and support for 16750 compatible Auto Flow Control.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The driver core clears the driver data to NULL after device_release
or on probe failure. Thus, it is not needed to manually clear the
device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The channel IDs are set to -1 by default. It will prevent
dmaengine from trying to provide the first free channel if
it fails to allocate exclusive channel. This will fix an
issue with ACPI enumerated UARTs that do not support DMA
but still end up getting a DMA channel incorrectly.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It should be available for DT users as well. This does not
enable DMA by default except with ACPI. DT users can enable
DMA based on a property.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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DMA engines usually expect the fifo trigger level to be
aligned with the burst size. It should not be changed even
with small baud rates. This will fix an issue with
Designware DMA engine where the data can not be transferred
over UART with lower baud rates then 2400.
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When a serial port is configured for RTS/CTS flow control, serial core
will disable the transmitter if it observes CTS is de-asserted. This is
perfectly reasonable and appropriate when the UART lacks the ability to
automatically perform CTS flow control.
However, if the UART hardware can manage flow control automatically, it
is important that software not get involved. When the DesignWare UART
enables 16C750 style auto-RTS/CTS it stops generating interrupts for
changes in CTS state so software mostly stays out of the way. However,
it does report the true state of CTS in the MSR so software may notice
it is de-asserted and respond by improperly disabling the transmitter.
Once this happens the transmitter will be blocked forever.
To avoid this situation, we simply lie to the 8250 and serial core by
reporting that CTS is asserted whenever auto-RTS/CTS mode is enabled.
Signed-off-by: Tim Kryger <tim.kryger@linaro.org>
Reviewed-by: Matt Porter <matt.porter@linaro.org>
Reviewed-by: Markus Mayer <markus.mayer@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Fix the following sparse warning:
drivers/tty/serial/8250/8250_early.c:196:26: error: incompatible types in comparison expression (different type sizes)
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We want the tty fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Use the wrapper function for retrieving the platform data instead of
accessing dev->platform_data directly.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We can't use dev->mod_index for selecting the interrupt routing entry,
because it's not an index into interrupt routing table. It will be even
wrong on a machine with 2 CPUs (4 cores). But all needed information is
contained in the PAT entries for the serial ports. mod[0] contains the
iosapic address and mod_info has some indications for the interrupt
input (at least it looks like it). This patch implements the searching
for the right iosapic and uses this interrupt input information.
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: <stable@vger.kernel.org> # 3.10
Signed-off-by: Helge Deller <deller@gmx.de>
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We want the tty fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Replace kzalloc and clk_get by their managed counterparts to simplify
error and cleanup paths.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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