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: NStephen Warren <swarren@nvidia.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using RX DMA, the driver won't pass any data to the uart layer
until the buffer is flipped. When the port is shutdown, the dma buffers
are unmapped, but the head and tail of the ring buffer are not reseted.
Since the serial console will keep the port open, this will only
present itself when the uart is not shared.

To reproduce the issue, with an unpatched driver, run a getty on /dev/ttyS0
with no serial console and exit. Getty will exit, and when the new one returns
you will be unable to log in.  If you hold down a key long enough to fill the
DMA buffer and flip it, you can then log in.
Signed-off-by: NMark Deneen <mdeneen@gmail.com>
Acked-by: NLeilei Zhao <leilei.zhao@atmel.com>
[nicolas.ferre@atmel.com: adapt to mainline kernel, handle !DMA case]
Cc: <stable@vger.kernel.org> # v3.12
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The _remove callback could be called when a tasklet is scheduled. tasklet_kill
was called inside the function in order to free up any scheduled tasklets.
However it was called after uart_remove_one_port which destroys tty references
needed in the port for atmel_tasklet_func.
Simply putting the tasklet_kill at the start of the function will prevent this
conflict.
Signed-off-by: NMarek Roszko <mark.roszko@gmail.com>
Acked-by: NLeilei Zhao <leilei.zhao@atmel.com>
Cc: <stable@vger.kernel.org> # v3.12
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Interrupts were being cleaned up late in the shutdown handler, it is possible
that an interrupt can occur and schedule a tasklet that runs after the port is
cleaned up. There is a null dereference due to this race condition with the
following stacktrace:

[<c02092b0>] (atmel_tasklet_func+0x514/0x814) from [<c001fd34>] (tasklet_action+0x70/0xa8)
[<c001fd34>] (tasklet_action+0x70/0xa8) from [<c001f60c>] (__do_softirq+0x90/0x144)
[<c001f60c>] (__do_softirq+0x90/0x144) from [<c001fa18>] (irq_exit+0x40/0x4c)
[<c001fa18>] (irq_exit+0x40/0x4c) from [<c000e298>] (handle_IRQ+0x64/0x84)
[<c000e298>] (handle_IRQ+0x64/0x84) from [<c000d6c0>] (__irq_svc+0x40/0x50)
[<c000d6c0>] (__irq_svc+0x40/0x50) from [<c0208060>] (atmel_rx_dma_release+0x88/0xb8)
[<c0208060>] (atmel_rx_dma_release+0x88/0xb8) from [<c0209740>] (atmel_shutdown+0x104/0x160)
[<c0209740>] (atmel_shutdown+0x104/0x160) from [<c0205e8c>] (uart_port_shutdown+0x2c/0x38)
Signed-off-by: NMarek Roszko <mark.roszko@gmail.com>
Acked-by: NLeilei Zhao <leilei.zhao@atmel.com>
Cc: <stable@vger.kernel.org> # v3.12
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In rx dma-callback it calls tasklet_schedule, if the tasklet
be scheduled after all the dma-callback in the rx dma channel,
current check condition in the tasklet will not do fetch dma
buffer into tty because tx_issued is equal with tx_completed,
so as timeout tasklet does.

so we check whether we should fetch the whole dma buffer into
tty according to the status of transactions in rx dma channel.
Signed-off-by: NQipan Li <Qipan.Li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

this patch provides PM entry of uart_ops, then drop clk enable and
disable because serial core will do it.

the patch also fixes the issue that uart hang in resume caused by
not-enabled clock.
Signed-off-by: NQipan Li <Qipan.Li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

use SET_SYSTEM_SLEEP_PM_OPS to initialize suspend/resume functions
instead of legacy suspend and resume entries of platform_driver.
this will add hibernation support automatically as suspend to disk
entries are also set.
Signed-off-by: NQipan Li <Qipan.Li@csr.com>
Signed-off-by: NBarry Song <Baohua.Song@csr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This helps increasing build testing coverage.
To do this, read{write}_relaxed() functions was be replaced with
simple read{write}() variants. Potential "uninitialized variable"
warnings was be fixed if driver compiled without MFD_SYSCON.
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch replace custom handling of IrDA feature with N_IRDA
line discipline, so IrDA mode can be used with irtty driver.
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

New driver for NXP (Philips) UART ICs was introduced in September 2012.
Old driver no longer used anywhere, this patch removes it.
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NYegor Yefremov <yegorslists@googlemail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 'tty: xuartps: Implement BREAK detection, add SYSRQ support'
(0c0c47bc) introduced sysrq support
without properly guarding sysrq specific code which results in build
errors when sysrq is disabled:
	DNAME=KBUILD_STR(xilinx_uartps)" -c -o
	drivers/tty/serial/.tmp_xilinx_uartps.o
	drivers/tty/serial/xilinx_uartps.c
	drivers/tty/serial/xilinx_uartps.c: In function 'xuartps_isr':
	drivers/tty/serial/xilinx_uartps.c:247:5: error: 'struct uart_port'
	has no member named 'sysrq'
	drivers/tty/serial/xilinx_uartps.c:247:5: error: 'struct uart_port'
	has no member named 'sysrq'
	drivers/tty/serial/xilinx_uartps.c:247:5: error: 'struct uart_port'
	has no member named 'sysrq'
	make[3]: *** [drivers/tty/serial/xilinx_uartps.o] Error 1
Reported-by: NMasanari Iida <standby24x7@gmail.com>
Cc: Vlad Lungu <vlad.lungu@windriver.com>
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NMark Brown <broonie@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NMika Westerberg <mika.westerberg@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When falling back from DMA to interrupt mode the receive interrupt has to
be re-enabled to catch new incoming data.
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In pl011_rx_chars() if pl011_dma_rx_trigger_dma() succeeds it will disable
the receive interrupt, no need to do this again.
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

During initialisation, a UART may already be in use for a console, so
take care to preserve things like baud rate and data format to avoid
corrupting console output.
Signed-off-by: NJon Medhurst <tixy@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The code to cope with a split tx/rx LCR_H register is non-trivial
so put it into it's own function to avoid duplication.
Signed-off-by: NJon Medhurst <tixy@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the pl011 is being used for a console, pl011_console_write forces
the control register (CR) to enable the UART for transmission and then
restores this to the original value afterwards. It does this while
holding the port lock.

Unfortunately, when the uart is started or shutdown - say in response to
userland using the serial device for a terminal - then this updates the
control register without any locking.

This means we can have

  pl011_console_write   Save CR
  pl011_startup         Initialise CR, e.g. enable receive
  pl011_console_write   Restore old CR with receive not enabled

this result is a serial port which doesn't respond to any input.

A similar race in reverse could happen when the device is shutdown.

We can fix these problems by taking the port lock when updating CR.
Signed-off-by: NJon Medhurst <tixy@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 17438217 on request
of Linus Walleij:
	Greg can you please drop or revert
	commit 17438217
	"serial: pl011: use DMA RX polling by default"
	from the TTY tree until this has been sorted out?

Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This is a complex patch for refactoring CLPS711X serial driver.
Major changes:
- Eliminate <mach/hardware.h> usage.
- Devicetree support.
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit c49436b6 (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: NJames 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: NTim Kryger <tim.kryger@linaro.org>
Tested-by: NEzequiel Garcia <ezequiel.garcia@free-electrons.com>
Tested-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

clk_prepare_enable() may fail, so let's check its return value and propagate it
in the case of error.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert to modern PM ops and use the SIMPLE_DEV_PM_OPS macro to set up
the PM callbacks.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Don't use DEFINE_PCI_DEVICE_TABLE macro, because this macro
is not preferred.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add the loopback mode support for imx uart driver.
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Making DMA RX polling optional when DMA is on was just
over-cautious: there is one single system in the kernel tree
using this facility, Ux500 and after some testing I turned
this on also for Ux500, which means it should simply be on
by default if DMA is enabled.

Cc: Jongsung Kim <neidhard.kim@lge.com>
Cc: Chanho Min <chanho.min@lge.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert to modern PM ops and use the SIMPLE_DEV_PM_OPS macro to set up
the PM callbacks.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This early amba_ports declaration was introduced by commit c16d51a3 (amba
pl011: workaround for uart registers lockup) for use in the pl011_lockup_wa()
routine. This routine was later removed by commit 4fd0690b (serial: pl011:
implement workaround for CTS clear event issue).
Signed-off-by: NBaruch Siach <baruch@tkos.co.il>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI now provides stubs for the functions the driver uses.
Signed-off-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The uart_set_options() code unconditionally initalizes the spinlock
on the port. This can cause a deadlock in some situations.

One instance that exposed the problem, was when writing to
/sys/module/kgdboc/parameters/kgdboc to use ttyS0 when the console
is already running on ttyS0. If the spinlock is re-initialized
while the lock is held due to output to the console, there
is a deadlock.

Assume the spinlock is initialized if the port is a console.
Signed-off-by: NRandy Witt <rewitt@declaratino.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When booting a multi-platform m68k kernel on a non-Mac with "console=ttyS0"
on the kernel command line, it crashes with:

Unable to handle kernel NULL pointer dereference at virtual address   (null)
Oops: 00000000
PC: [<0013ad28>] __pmz_startup+0x32/0x2a0
...
Call Trace: [<002c5d3e>] pmz_console_setup+0x64/0xe4

The normal tty driver doesn't crash, because init_pmz() checks
pmz_ports_count again after calling pmz_probe().

In the serial console initialization path, pmz_console_init() doesn't do
this, causing the driver to crash later.

Add a check for pmz_ports_count to fix this.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Cc: Finn Thain <fthain@telegraphics.com.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 9326b047 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=60724Reported-by: NChristoph Biedl <bugzilla.kernel.bpeb@manchmal.in-ulm.de>
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>,
Signed-off-by: NPhilippe Proulx <philippe.proulx@savoirfairelinux.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Renesas ARM platforms are transitioning from single-platform to
multi-platform kernels using the new ARCH_SHMOBILE_MULTI. Make the
driver available on all ARM platforms to enable it on both ARCH_SHMOBILE
and ARCH_SHMOBILE_MULTI, and increase build testing coverage with
COMPILE_TEST.
Signed-off-by: NLaurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These local symbols are used only in this file.
Fix the following sparse warnings:

drivers/tty/serial/mfd.c:296:6: warning: symbol 'hsu_dma_tx' was not declared. Should it be static?
drivers/tty/serial/mfd.c:343:6: warning: symbol 'hsu_dma_start_rx_chan' was not declared. Should it be static?
drivers/tty/serial/mfd.c:389:6: warning: symbol 'hsu_dma_rx' was not declared. Should it be static?
drivers/tty/serial/mfd.c:1186:17: warning: symbol 'serial_hsu_pops' was not declared. Should it be static?
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NPhilippe Proulx <philippe.proulx@savoirfairelinux.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If RS-485 is enabled, make the OMAP UART fire THR interrupts when both
TX FIFO and TX shift register are empty instead of polling the
equivalent status bit. This removes the burst of interrupt requests
seen at every end of transmission.

Also: the comment said that the TX FIFO trigger level was set at 16
characters when it's 32 in reality.
Signed-off-by: NPhilippe Proulx <philippe.proulx@savoirfairelinux.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>