The platform_get_irq can return error. Assigning the return value to an
unsigned variable and checking it for negative value will always return
false.

Use an intermediate signed variable to get IRQ information, check for any
error and then assign it to 'irq' variable inside uart_port structure.
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 99492c39 ("earlycon: Fix __earlycon_table stride") tried to fix
__earlycon_table stride by forcing the earlycon_id struct alignment to 32
and asking the linker to 32-byte align the __earlycon_table symbol.  This
fix was based on commit 07fca0e5 ("tracing: Properly align linker
defined symbols") which tried a similar fix for the tracing subsystem.

However, this fix doesn't quite work because there is no guarantee that
gcc will place structures packed into an array format.  In fact, gcc 4.9
chooses to 64-byte align these structs by inserting additional padding
between the entries because it has no clue that they are supposed to be in
an array.  If we are unlucky, the linker will assign symbol
"__earlycon_table" to a 32-byte aligned address which does not correspond
to the 64-byte aligned contents of section "__earlycon_table".

To address this same problem, the fix to the tracing system was
subsequently re-implemented using a more robust table of pointers approach
by commits:
 3d56e331 ("tracing: Replace syscall_meta_data struct array with pointer array")
 65498646 ("tracepoints: Fix section alignment using pointer array")
 e4a9ea5e ("tracing: Replace trace_event struct array with pointer array")

Let's use this same "array of pointers to structs" approach for
EARLYCON_TABLE.

Fixes: 99492c39 ("earlycon: Fix __earlycon_table stride")
Signed-off-by: NDaniel Kurtz <djkurtz@chromium.org>
Suggested-by: NAaron Durbin <adurbin@chromium.org>
Reviewed-by: NRob Herring <robh@kernel.org>
Tested-by: NGuenter Roeck <groeck@chromium.org>
Reviewed-by: NGuenter Roeck <groeck@chromium.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

To reset the UART the SRST needs be cleared (low active). According
to the documentation the bit will remain active for 4 module clocks
until it is cleared (set to 1).

Hence the real register need to be read in case the cached register
indicates that the SRST bit is zero.

This bug lead to wrong baudrate because the baud rate register got
restored before reset completed in imx_flush_buffer.

Fixes: 3a0ab62f ("serial: imx: implement shadow registers for UCRx and UFCR")
Signed-off-by: NStefan Agner <stefan@agner.ch>
Reviewed-by: NFabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using half-duplex mode (which disables receiver during txing)
the RTS signal cannot be driven low during transmission when using
i.MX UART RTS/CTS control. This seems to be a limitation of the
i.MX UART IP: The RTS (CTS_B) signal is controlled by the receiver.
When the receiver is disabled, the signal stays in UART logic idle
state which is high...

If SER_RS485_RTS_ON_SEND is used, RTS needs to be high active during
transmission. Since this is the default state of the RTS (CTS_B)
signal when the receiver is off, half-duplex mode in this
configuration works fine.

However, a low-active RTS signal (flag SER_RS485_RTS_ON_SEND not set)
cannot be generated when the receiver is turned off.

Print an error if the user selects this unsupported configuration
(both SER_RS485_RTS_ON_SEND and SER_RS485_RX_DURING_TX unset) and
configure the closest working configuration (set the
SER_RS485_RX_DURING_TX flag).
Signed-off-by: NStefan Agner <stefan@agner.ch>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 68a0db1d reworked the baud rate selection, but also added
a (not so) subtle change in the way the local flags (c_lflag in the
termios structure) are handled, forcing the new flags to always be the
same as the old ones.

The reason for that particular change is both obscure and undocumented.
It also completely breaks userspace. Something as trivial as getty is
unusable:

<example>
	Debian GNU/Linux 9 sy-borg ttyMV0

	sy-borg login: root
	root
	[timeout]

	Debian GNU/Linux 9 sy-borg ttyMV0
</example>

which is quite obvious in retrospect: getty cannot get in control of
the echo mode, is stuck in canonical mode, and times out without ever
seeing anything valid. It also begs the question of how this change was
ever tested.

The fix is pretty obvious: stop messing with c_lflag, and the world
will be a happier place.

Cc: stable@vger.kernel.org # 4.15+
Fixes: 68a0db1d ("serial: mvebu-uart: add function to change baudrate")
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

At least on droid 4 with control channel in ADM mode, there is no response
to Modem Status Command (MSC). Currently gsmtty_modem_update() expects to
have data in dlci->modem_rx unless debug & 2 is set. This means that on
droid 4, things only work if debug & 2 is set.

Let's fix the issue by ignoring empty dlci->modem_rx for ADM mode. In
the AMD mode, CMD_MSC will never respond and gsm_process_modem() won't
get called to set dlci->modem_rx.

And according to ts_127010v140000p.pdf, MSC is only relevant if basic
option is chosen, so let's test for that too.

Fixes: ea3d8465 ("tty: n_gsm: Allow ADM response in addition to UA for control dlci")
Cc: linux-serial@vger.kernel.org
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Jiri Prchal <jiri.prchal@aksignal.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
Cc: Michael Scott <michael.scott@linaro.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Russ Gorby <russ.gorby@intel.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit ea3d8465 ("tty: n_gsm: Allow ADM response in addition to UA for
control dlci") added support for DLCI to stay in Asynchronous Disconnected
Mode (ADM). But we still get long delays waiting for commands to other
DLCI to complete:

--> 5) C: SABM(P)
Q>  0) C: UIH(F)
Q>  0) C: UIH(F)
Q>  0) C: UIH(F)
...

This happens because gsm_control_send() sets cretries timer to T2 that is
by default set to 34. This will cause resend for T2 times for the control
frame. In ADM mode, we will never get a response so the control frame, so
retries are just delaying all the commands.

Let's fix the issue by setting DLCI_MODE_ADM flag after detecting the ADM
mode for the control DLCI. Then we can use that in gsm_control_send() to
set retries to 1. This means the control frame will be sent once allowing
the other end at an opportunity to switch from ADM to ABM mode.

Note that retries will be decremented in gsm_control_retransmit() so
we don't want to set it to 0 here.

Fixes: ea3d8465 ("tty: n_gsm: Allow ADM response in addition to UA for control dlci")
Cc: linux-serial@vger.kernel.org
Cc: Alan Cox <alan@llwyncelyn.cymru>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Jiri Prchal <jiri.prchal@aksignal.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Marcel Partap <mpartap@gmx.net>
Cc: Merlijn Wajer <merlijn@wizzup.org>
Cc: Michael Nazzareno Trimarchi <michael@amarulasolutions.com>
Cc: Michael Scott <michael.scott@linaro.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Russ Gorby <russ.gorby@intel.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Using this helper allows us to avoid the in-kernel calls to the
sys_ioperm() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_ioperm().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: x86@kernel.org
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>

Using this helper allows us to avoid the in-kernel calls to the
sys_sync() syscall. The ksys_ prefix denotes that this function
is meant as a drop-in replacement for the syscall. In particular, it
uses the same calling convention as sys_sync().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NDominik Brodowski <linux@dominikbrodowski.net>

The Tile architecture is obsolete and getting removed from the kernel,
this removes the corresponding console driver as well.
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

The blackfin architecture is getting removed, so these drivers
are not needed any more.
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NAaron Wu <aaron.wu@analog.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

The tile architecture is getting removed, and this driver is
useless without it.
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

The m32r architecture is getting removed, so we don't need this
any more.
Acked-by: NNicolas Pitre <nico@fluxnic.net>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

The blackfin architecture is getting removed, so both the bfin_uart
and bfin_sport_uart can be removed as well.
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NAaron Wu <aaron.wu@analog.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

The cris architecture is getting removed, so we don't need the
uart driver any more.
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>

Tabs on a console with long lines do not wrap properly, so correctly
account for the line length when computing the tab placement location.
Reported-by: NJames Holderness <j4_james@hotmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The buf_overrun count is only every written, and not exposed to
userspace anywhere. This means that dropped characters due to flip
buffer overruns are never visible to userspace.

The /proc/tty/driver/serial file exports a bunch of metrics (including
hardware overruns) already, so add the buf_overrun (as "bo:") to this
file.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes missing characters on kernel console at low baud rates (i.e.9600).
The driver should poll TX_RDY or TX_FIFO_EMP instead of TX_EMP to ensure
that the transmitter holding register (THR) is ready to receive a new byte.

TX_EMP tells us when it is possible to send a break sequence via
SND_BRK_SEQ. While this also indicates that both the THR and the TSR are
empty, it does not guarantee that a new byte can be written just yet.

Fixes: 30530791 ("serial: mvebu-uart: initial support for Armada-3700 serial port")
Reviewed-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Acked-by: NGregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: NGabriel Matni <gabriel.matni@exfo.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In case of error, the function platform_get_resource() returns NULL
pointer not ERR_PTR(). The IS_ERR() test in the return value check
should be replaced with NULL test.

Fixes: c4f52879 ("tty: serial: msm_geni_serial: Add serial driver support for GENI based QUP")
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This driver supports GENI based UART Controller in the Qualcomm SOCs. The
Qualcomm Generic Interface (GENI) is a programmable module supporting a
wide range of serial interfaces including UART. This driver support console
operations using FIFO mode of transfer.
Signed-off-by: NGirish Mahadevan <girishm@codeaurora.org>
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Signed-off-by: NSagar Dharia <sdharia@codeaurora.org>
Signed-off-by: NDoug Anderson <dianders@google.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The S390 architecture does not support any graphics hardware,
but with the latest support for Virtio GPU in Linux and Virtio
GPU emulation in QEMU, it's possible to enable graphics for
S390 using the Virtio GPU device.

To enable display we need to enable the Linux Virtual Terminal (VT)
layer for S390. But the VT subsystem initializes quite early
at boot so we need a dummy console driver till the Virtio GPU
driver is initialized and we can run the framebuffer console.

The framebuffer console over a Virtio GPU device can be run
in combination with the serial SCLP console (default on S390).
The SCLP console can still be accessed by management applications
(eg: via Libvirt's virsh console).
Signed-off-by: NFarhan Ali <alifm@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Message-Id: <e23b61f4f599ba23881727a1e8880e9d60cc6a48.1519315352.git.alifm@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>

Add support for two MEN UARTs (16z025 and 16z057) to the
8250_men_mcb driver.
The 16z025 consists of up to four ports, the 16z057 has
exactly four ports. Apart from that, all of them share the
Port settings.
Signed-off-by: NMichael Moese <mmoese@suse.de>
Reported-by: NBen Turner <ben.turner@21net.com>
Tested-by: NBen Turner <ben.turner@21net.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Configure RS485 mode during port initialization.

Fixes: 1bcda09d ("serial: stm32: add support for RS485 hardware control mode")
Signed-off-by: NBich Hemon <bich.hemon@st.com>
Acked-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The S390 architecture does not support any graphics hardware,
but with the latest support for Virtio GPU in Linux and Virtio
GPU emulation in QEMU, it's possible to enable graphics for
S390 using the Virtio GPU device.

To enable display we need to enable the Linux Virtual Terminal (VT)
layer for S390. But the VT subsystem initializes quite early
at boot so we need a dummy console driver till the Virtio GPU
driver is initialized and we can run the framebuffer console.

The framebuffer console over a Virtio GPU device can be run
in combination with the serial SCLP console (default on S390).
The SCLP console can still be accessed by management applications
(eg: via Libvirt's virsh console).
Signed-off-by: NFarhan Ali <alifm@linux.vnet.ibm.com>
Acked-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Reviewed-by: NThomas Huth <thuth@redhat.com>
Message-Id: <e23b61f4f599ba23881727a1e8880e9d60cc6a48.1519315352.git.alifm@linux.vnet.ibm.com>
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

ECMA-48 [1] (aka ISO 6429) has defined SGR 21 as "doubly underlined"
since at least March 1984.  The Linux kernel has treated it as SGR 22
"normal intensity" since it was added in Linux-0.96b in June 1992.
Before that, it was simply ignored.  Other terminal emulators have
either ignored it, or treat it as double underline now.  xterm for
example added support in its 304 release (May 2014) [2] where it was
previously ignoring it.

Changing this behavior shouldn't be an issue:
- It isn't a named capability in ncurses's terminfo database, so no
  script is using libtinfo/libcurses to look this up, or using tput
  to query & output the right sequence.
- Any script assuming SGR 21 will reset intensity in all terminals
  already do not work correctly on non-Linux VTs (including running
  under screen/tmux/etc...).
- If someone has written a script that only runs in the Linux VT, and
  they're using SGR 21 (instead of SGR 22), the output should still
  be readable.

imo it's important to change this as the Linux VT's non-conformance
is sometimes used as an argument for other terminal emulators to not
implement SGR 21 at all, or do so incorrectly.

[1]: https://www.ecma-international.org/publications/standards/Ecma-048.htm
[2]: https://github.com/ThomasDickey/xterm-snapshots/commit/2fd29cb98d214cb536bcafbee00bc73b3f1eeb9dSigned-off-by: NMike Frysinger <vapier@chromium.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix function name in serdev_device_alloc() definition
Signed-off-by: NFrédéric Danis <frederic.danis.oss@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since dtc v1.4.6-9-gaadd0b65c987, aliases property name
must include only lowercase and '-'.

After having updated all STi boards serial aliases from "ttyASN"
to "serialN", st-asc driver need to be updated accordingly as tty
aliases id is retrieved using of_alias_get_id().
Signed-off-by: NPatrice Chotard <patrice.chotard@st.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implement Driver Enable signal (DE) to activate the transmission mode
of the external transceiver.
Signed-off-by: NYves Coppeaux <yves.coppeaux@st.com>
Signed-off-by: NBich Hemon <bich.hemon@st.com>
Signed-off-by: NGreg 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: NRob Herring <robh@kernel.org>
Signed-off-by: NJoel Stanley <joel@jms.id.au>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In case of Alphascale ASM9260 probe() enables s->clk and s->clk_ahb
via mxs_get_clks(), but there is no disable of the clocks.
The patch adds it to error paths and to mxs_auart_remove().

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Fixes: 254da0d7 ("serial: mxs-auart: add Alphascale ASM9260 support")
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Special settings for APMC0D08 are applied when device is present
in the system. To check its presence we may use acpi_dev_present()
instead of current open coded variant.

Cc: Feng Kan <fkan@apm.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Having a fixed prefix helps at several places. It ensures that another
driver doesn't use the same function name which confuses the linker and
tools like ctags. It simplifies working with function tracing and
dynamic printk() support which can filter on function names. And last
but not least it helps the human source code reader to understand if a
given function belongs to a driver or a more general part of the kernel.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

serial_core might call the .start_tx callback without any data being
available to send. In this case return early instead of going through
all the setup needed for sending which might include disabling RX in
RS485 half-duplex mode.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using RS485 half duplex the Transmitter Complete irq is needed to
determine the moment when the transmitter can be disabled. When using
DMA this irq must only be enabled when DMA has completed to transfer all
data. Otherwise the CPU might busily trigger this irq which is not
properly handled and so the also pending irq for the DMA transfer cannot
trigger.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows to increase the RX waterlevel which allows to delay the RRDY
irq. The desired effect is that less irqs are needed to handle
characters and so reduce irq count of the system.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure that UCR1.RXDMAEN and UCR1.ATDMAEN (for the DMA case) and
UCR1.RRDYEN (for the PIO case) are off iff UCR1.RXEN is disabled. This
ensures that the fifo isn't read with RX disabled which results in an
exception.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the UART is used in DMA mode, .stop_rx() does nothing if the port
isn't suspended. This is wrong as .stop_rx() should stop receiving
characters unconditionally. When the port is about to be closed the DMA
channel is stopped in .shutdown(), so this isn't necessary to be in
.stop_rx() here, too.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The aging timer fires if there are characters in the RX fifo but the
water level isn't reached yet. Make sure that the waterlevel is
configured before the aging timer is enabled to trigger a DMA request
(UCR1_ATDMAEN).
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The serial/imx driver is full of inconsistently named and typed
variables that hold different register values.

Consistently use u32 as type (matching what readl and writel use) and
name the variables after the register whose value they are holding.
This makes it easier to notice when UCR2_RTSEN is written to UCR1.

The only difference introduced by this commit in the compiled driver is
that twice the second argument to warn_slowpath_null() changed because the
two WARN_ON in dma_rx_callback() pass __LINE__ to warn_slowpath_null().
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The original code looks as follows:

	if (sport->dma_is_enabled) {
		... make sure TX DMA is running, i.e. .dma_is_txing = 1
	}

	if (sport->dma_is_txing)
		return;

As .dma_is_txing can only be true if .dma_is_enabled is, the return can
go at the end of the first if body without an additional check.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>