On a Rockchip rk3399-based board during suspend/resume testing, we
found that we could get the console UART into a state where it would
print this to the console a lot:
  serial8250: too much work for irq42

Followed eventually by:
  NMI watchdog: BUG: soft lockup - CPU#0 stuck for 11s!

Upon debugging I found that we're in this state:
  iir = 0x000000cc
  lsr = 0x00000060

It appears that somehow we have a RX Timeout interrupt but there is no
actual data present to receive.  When we're in this state the UART
driver claims that it handled the interrupt but it actually doesn't
really do anything.  This means that we keep getting the interrupt
over and over again.

Normally we don't actually need to do anything special to handle a RX
Timeout interrupt.  We'll notice that there is some data ready and
we'll read it, which will end up clearing the RX Timeout.  In this
case we have a problem specifically because we got the RX TImeout
without any data.  Reading a bogus byte is confirmed to get us out of
this state.

It's unclear how exactly the UART got into this state, but it is known
that the UART lines are essentially undriven and unpowered during
suspend, so possibly during resume some garbage / half transmitted
bits are seen on the line and put the UART into this state.

The UART on the rk3399 is a DesignWare based 8250 UART.  From mailing
list posts, it appears that other people have run into similar
problems with DesignWare based IP.  Presumably this problem is unique
to that IP, so I have placed the workaround there to avoid possibly of
accidentally triggering bad behavior on other IP.  Also note the RX
Timeout behaves very differently in the DMA case, for for now the
workaround is only applied to the non-DMA case.
Signed-off-by: NDouglas Anderson <dianders@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

My static checker complains that we don't have any error handling here.
It's simple enough to add it.

Fixes: bed35c6d ("serdev: add a tty port controller driver")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fixes the following sparse warning:

drivers/tty/serial/8250/8250_pci.c:3916:6: warning:
 symbol 'pciserial_detach_ports' was not declared. Should it be static?
Signed-off-by: NWei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Hardware flow-control capability must be specified at a platform
level in order to inform the ASC driver that the platform is capable
(i.e. are the lines wired up, etc).  STiH4{07,10} devices are indeed
capable, so let's provide the property.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Having just defined some new Pinctrl groups for when HW flow-control
is {en,dis}abled, let's reference them for use within the driver.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Each serial port which supports HW flow-control should have 2 Pinctrl
groups.  One for when HW flow-control is in progress, where the IP
will take over controlling the lines and another group which enables
the lines to be toggled using GPIO mechanisms.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When hardware flow-control is disabled, manual toggling of the UART's
reset line (RTS) using userland applications (e.g. stty) is not
possible, since the ASC IP does not provide this functionality in the
same was as some other IPs do.  Thus, we have to do this manually.
This patch configures the UART RTS line as a GPIO for manipulation
within the UART driver when HW flow-control is not enabled.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

'uart-has-rtscts' property and 'rts-gpios|cts-gpios' are normally
mutually exclusive, however it is possible for some drivers to have
a dynamic approach, meaning that both properties can be relevant.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The initial binding 'st,hw-flow-control' isn't used anywhere, in neither
in upstream nor downstream kernels.  It isn't even documented in
dt-bindings, so we can safely assume it's safe to swap to the generic
one.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When hardware flow-control is disabled, manual toggling of the UART's
reset line (RTS) using userland applications (e.g. stty) is not
possible, since the ASC IP does not provide this functionality in the
same was as some other IPs do.  Thus, we have to do this manually.

This patch ensures that when HW flow-control is disabled the RTS/CTS
lines are free to be registered via the GPIO API.  It also ensures
any registered GPIO lines are unregistered when HW flow-control is
requested, allowing the IP to control them automatically.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There are now 2 possible separate/different Pinctrl states which can
be provided from platform data.  One which encompasses the lines
required for HW flow-control (CTS/RTS) and another which does not
specify these lines, such that they can be used via GPIO mechanisms
for manually toggling (i.e. from a request by `stty`).
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Until this point, it has not been possible for userland serial
applications (e.g. stty) to toggle the UART RTS line.  This can
be useful with certain configurations. For example, when using
a Mezzanine on a Linaro 96board, RTS line is used to take the
on-board microcontroller in and out of reset.
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The datasheet states:

"If the MODE field selects an 8-bit frame then this [parity error] bit
 is undefined. Software should ignore this bit when reading 8-bit frames."
Acked-by: NPeter Griffin <peter.griffin@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The MKS Instruments SCOM-0800 and SCOM-0801 cards (originally by Tenta
Technologies) are 3U CompactPCI serial cards with 4 and 8 serial ports,
respectively.  The first 4 ports are implemented by an OX16PCI954 chip,
and the second 4 ports are implemented by an OX16C954 chip on a local
bus, bridged by the second PCI function of the OX16PCI954.  The ports
are jumper-selectable as RS-232 and RS-422/485, and the UARTs use a
non-standard oscillator frequency of 20 MHz (base_baud = 1250000).
Signed-off-by: NIan Abbott <abbotti@mev.co.uk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Allows tuning of the RX FIFO fill threshold and timeout. (The latter is
only applicable to SCIFA and SCIFB).
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implements support for FIFO fill thresholds greater than one with software
timeout.

This mechanism is not possible (or at least not useful) on SCIF family
hardware other than SCIFA and SCIFB because they do not support turning off
the DR hardware timeout interrupt separately from the RI interrupt.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Sets reasonable trigger defaults for the various SCIF variants.
Also corrects the FIFO size for SH7705-style ports.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Register a serdev controller with the serdev bus when a tty_port is
registered. This creates the serdev controller and create's serdev
devices for any DT child nodes of the tty_port's parent (i.e. the UART
device).
Signed-off-by: NRob Herring <robh@kernel.org>
Reviewed-By: NSebastian Reichel <sre@kernel.org>
Tested-By: NSebastian Reichel <sre@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a serdev controller driver for tty ports.

The controller is registered with serdev when tty ports are registered
with the TTY core. As the TTY core is built-in only, this has the side
effect of making serdev built-in as well.
Signed-off-by: NRob Herring <robh@kernel.org>
Reviewed-By: NSebastian Reichel <sre@kernel.org>
Tested-By: NSebastian Reichel <sre@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The serdev bus is designed for devices such as Bluetooth, WiFi, GPS
and NFC connected to UARTs on host processors. Tradionally these have
been handled with tty line disciplines, rfkill, and userspace glue such
as hciattach. This approach has many drawbacks since it doesn't fit
into the Linux driver model. Handling of sideband signals, power control
and firmware loading are the main issues.

This creates a serdev bus with controllers (i.e. host serial ports) and
attached devices. Typically, these are point to point connections, but
some devices have muxing protocols or a h/w mux is conceivable. Any
muxing is not yet supported with the serdev bus.
Signed-off-by: NRob Herring <robh@kernel.org>
Reviewed-By: NSebastian Reichel <sre@kernel.org>
Tested-By: NSebastian Reichel <sre@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a common binding for describing serial/UART attached devices. Common
examples are Bluetooth, WiFi, NFC and GPS devices.

Serial attached devices are represented as child nodes of a UART node.
This may need to be extended for more complex devices with multiple
interfaces, but for the simple cases a child node is sufficient.
Tested-By: NSebastian Reichel <sre@kernel.org>
Signed-off-by: NRob Herring <robh@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce a client (upward direction) operations struct for tty_port
clients. Initially supported operations are for receiving data and write
wake-up. This will allow for having clients other than an ldisc.

Convert the calls to the ldisc to use the client ops as the default
operations.
Signed-off-by: NRob Herring <robh@kernel.org>
Reviewed-By: NSebastian Reichel <sre@kernel.org>
Tested-By: NSebastian Reichel <sre@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Sets the closest match for a desired RX trigger level.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

To allow operation with a higher RX FIFO interrupt threshold in PIO
mode, it is necessary to consider the DR bit ("FIFO not full, but no
data received for 1.5 frames") as an indicator that data can be read.
Otherwise the driver will let data rot in the FIFO until the threshold
is reached.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Defines the bits controlling FIFO thresholds, adds the additional
HSCIF registers to the register map.
Signed-off-by: NUlrich Hecht <ulrich.hecht+renesas@gmail.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of open-coding loop with of_find_node_by_type(), let's use canned
macro.
Signed-off-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit c7cef0a8 ("console: Add extensible console matching") added
match() method to struct console which allows the console to perform
console command line matching instead of (or in addition to) default
console matching (ie., by fixed name and index).

Commit ad1696f6 ("ACPI: parse SPCR and enable matching console")
introduced support for SPCR as matching console.

Commit 10879ae5 ("serial: pl011: add console matching function")
added the match method for pl011 console which checks for the console
string to be "pl011"

Now on a platform which has both SPCR in the ACPI tables and ttyAMA in
the command line, the ttyAMA is chosen as "selected console" but it
doesn't pass the matching console method which results in CON_CONSDEV
not being set on the "selected console".

As a result of that, the bootconsole(SPCR in the above case) is not
unregistered and all the beginning boot messages are seen twice.

This patch adds "ttyAMA" so that it's considered to match pl011 console.

Fixes: 10879ae5 ("serial: pl011: add console matching function")
Cc: Russell King <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Aleksey Makarov <aleksey.makarov@linaro.org>
Signed-off-by: NSudeep Holla <sudeep.holla@arm.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Ensure that the uart clock is enabled prior to writing to the
interrupt mask register in s3c24xx_serial_resume_noirq function.
Without enabing the uart clock, the uart register cannot be accessed.
Signed-off-by: NYoungmin Nam <youngmin.nam@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove the Exar specific codes from 8250_pci and blacklist those chips
so that the new Exar serial driver binds to the devices.
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NSudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add the serial driver for the Exar chips. And also register the
platform device for the GPIO provided by the Exar chips.
Reviewed-by: NAndy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: NSudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When userspace passes the SER_RS485_RTS_ON_SEND flag it means that the
CTS_B pin should go to logic level high before the transmission begins.

CTS_B goes to logic level high when both CTSC and CTS bits are cleared.

When userspace passes the SER_RS485_RTS_AFTER_SEND flag it means that the
CTS_B pin should go to logic level low after the transmission finishes.

CTS_B goes to logic level low when CTSC bit is cleared and CTS bit is set.

So fix the CTS_B polarity logic.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On a board that needs to drive RTS GPIO high in order to enable the
transmission of a RS485 transceiver the following description is
passed in the devide tree:

&uart4 {
        pinctrl-names = "default";
        pinctrl-0 = <&pinctrl_uart4>;
        rts-gpios = <&gpio6 2 GPIO_ACTIVE_HIGH>;
        status = "okay";
};

and userspace configures the uart port as follows:

/* enable RS485 mode: */
rs485conf.flags |= SER_RS485_ENABLED;

/* set logical level for RTS pin equal to 1 when sending: */
rs485conf.flags |= SER_RS485_RTS_ON_SEND;

/* set logical level for RTS pin equal to 0 after sending: */
rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);

However the RTS GPIO polarity observed in the oscilloscope is inverted.

When the SER_RS485_RTS_ON_SEND flag is set the imx_port_rts_active()
function should be called and following the same logic when
SER_RS485_RTS_AFTER_SEND flag is cleared the imx_port_rts_inactive()
should be called.

Do such logic change so that RS485 communication in half duplex can
work successfully when the RTS GPIO pin is passed via device tree.
Signed-off-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

During build testing, I ran into a warning in a driver that I
had written myself at some point:

drivers/tty/serial/8250/8250_of.c: In function 'of_platform_serial_probe':
drivers/tty/serial/8250/8250_of.c:233:1: error: the frame size of 1200 bytes is larger than 1152 bytes [-Werror=frame-larger-than=]

This is harmless by itself, but it shows two other problems in
the driver:

- It still tries to be generic enough to handle all kinds of serial
  ports, where in reality the driver has been 8250-only for a while,
  and every other uart has its own DT support

- As a result of that generalization, we keep two copies of
  'struct uart_port' on the stack during probe(). This is completely
  unnessary.

Removing the last code dealing with unsupported port_type values
solves both problems nicely, and reduces the stack size.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As the function header of sci_parse_dt() is split in an unusual way,
"git diff" gets confused when changes to the body of the function are
made, and attributes them to the wrong function.

Reformat the function header to fix this.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Declare uart_ops structures as const as they are only stored in the ops
field of an uart_port structure. This field is of type const, so
uart_ops structures having this property can be made const too.

File size details before and after patching.
First line of every .o file shows the file size before patching
and second line shows the size after patching.

   text	   data	    bss	    dec	    hex	filename

   2977	    456	     64	   3497	    da9	drivers/tty/serial/amba-pl010.o
   3169	    272	     64	   3505	    db1	drivers/tty/serial/amba-pl010.o

   3109	    456	      0	   3565	    ded	drivers/tty/serial/efm32-uart.o
   3301	    272	      0	   3573	    df5	drivers/tty/serial/efm32-uart.o

  10668	    753	      1	  11422	   2c9e	drivers/tty/serial/icom.o
  10860	    561	      1	  11422	   2c9e	drivers/tty/serial/icom.o

  23904	    408	      8	  24320	   5f00	drivers/tty/serial/ioc3_serial.o
  24088	    224	      8	  24320	   5f00	drivers/tty/serial/ioc3_serial.o

  10516	    560	      4	  11080	   2b48	drivers/tty/serial/ioc4_serial.o
  10709	    368	      4	  11081	   2b49	drivers/tty/serial/ioc4_serial.o

   7853	    648	   1216	   9717	   25f5	drivers/tty/serial/mpsc.o
   8037	    456	   1216	   9709	   25ed	drivers/tty/serial/mpsc.o

  10248	    456	      0	  10704	   29d0	drivers/tty/serial/omap-serial.o
  10440	    272	      0	  10712	   29d8	drivers/tty/serial/omap-serial.o

   8122	    532	   1984	  10638	   298e	drivers/tty/serial/pmac_zilog.o
   8306	    340	   1984	  10630	   2986	drivers/tty/serial/pmac_zilog.o

   3808	    456	      0	   4264	   10a8	drivers/tty/serial/pxa.o
   4000	    264	      0	   4264	   10a8	drivers/tty/serial/pxa.o

  21781	   3864	      0	  25645	   642d	drivers/tty/serial/serial-tegra.o
  22037	   3608	      0	  25645	   642d	drivers/tty/serial/serial-tegra.o

   2481	    456	     96	   3033	    bd9	drivers/tty/serial/sprd_serial.o
   2673	    272	     96	   3041	    be1	drivers/tty/serial/sprd_serial.o

   5534	    300	    512	   6346	   18ca	drivers/tty/serial/vr41xx_siu.o
   5630	    204	    512	   6346	   18ca	drivers/tty/serial/vr41xx_siu.o

   6730	   1576	    128	   8434	   20f2	drivers/tty/serial/vt8500_serial.o
   6986	   1320	    128	   8434	   20f2	drivers/tty/serial/vt8500_serial.o

Cross compiled for mips architecture.

   3005	    488	      0	   3493	    da5	drivers/tty/serial/pnx8xxx_uart.o
   3189	    304	      0	   3493	    da5	drivers/tty/serial/pnx8xxx_uart.o

   4272	    196	   1056	   5524	   1594	drivers/tty/serial/dz.o
   4368	    100	   1056	   5524	   1594	drivers/tty/serial/dz.o

   6551	    144	     16	   6711	   1a37	drivers/tty/serial/ip22zilog.o
   6647	     48	     16	   6711	   1a37	drivers/tty/serial/ip22zilog.o

   9612	    428	   1520	  11560	   2d28	drivers/tty/serial/serial_txx9.o
   9708	    332	   1520	  11560	   2d28	drivers/tty/serial/serial_txx9.o

   4156	    296	     16	   4468	   1174	drivers/tty/serial/ar933x_uart.o
   4252	    200	     16	   4468	   1174	drivers/tty/serial/ar933x_uart.o

Cross compiled for arm archiecture.

  11716	   1780	     44	  13540	   34e4	drivers/tty/serial/sirfsoc_uart.o
  11808	   1688	     44	  13540	   34e4	drivers/tty/serial/sirfsoc_uart.o

  13352	    596	     56	  14004	   36b4	drivers/tty/serial/amba-pl011.o
  13444	    504	     56	  14004	   36b4	drivers/tty/serial/amba-pl011.o

Cross compiled for sparc architecture.

   4664	    528	     32	   5224	   1468	drivers/tty/serial/sunhv.o
   4848	    344	     32	   5224	   1468	drivers/tty/serial/sunhv.o

   8080	    332	     28	   8440	   20f8	drivers/tty/serial/sunzilog.o
   8184	    228	     28	   8440	   20f8	drivers/tty/serial/sunzilog.o

Cross compiled for ia64 architecture.

  10226	    549	    472	  11247	   2bef	drivers/tty/serial/sn_console.o
  10414	    365	    472	  11251	   2bf3	drivers/tty/serial/sn_console.o

The files drivers/tty/serial/zs.o, drivers/tty/serial/lpc32xx_hs.o and
drivers/tty/serial/lantiq.o did not compile.
Signed-off-by: NBhumika Goyal <bhumirks@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The impact of the persistent scrollback feature on the code size is
rather small, so the config option is removed. The feature stays
disabled by default and can be enabled by using the boot command line
parameter 'vgacon.scrollback_persistent=1' or by setting
VGACON_SOFT_SCROLLBACK_PERSISTENT_ENABLE_BY_DEFAULT=y.
Signed-off-by: NManuel Schölling <manuel.schoelling@gmx.de>
Suggested-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a scrollback buffers for each VGA console. The benefit is that
the scrollback history is not flushed when switching between consoles
but is persistent.
The buffers are allocated on demand when a new console is opened.

This breaks tools like clear_console that rely on flushing the
scrollback history by switching back and forth between consoles
which is why this feature is disabled by default.
Use the escape sequence \e[3J instead for flushing the buffer.
Signed-off-by: NManuel Schölling <manuel.schoelling@gmx.de>
Reviewed-by: NAndrey Utkin <andrey_utkin@fastmail.com>
Tested-by: NAndrey Utkin <andrey_utkin@fastmail.com>
Tested-by: NAdam Borowski <kilobyte@angband.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This new callback is in preparation for persistent scrollback buffer
support for VGA consoles.
With a single scrollback buffer for all consoles, we could flush the
buffer just by invocating consw->con_switch(). But when each VGA console
has its own scrollback buffer, we need a new callback to tell the
video console driver which buffer to flush.
Signed-off-by: NManuel Schölling <manuel.schoelling@gmx.de>
Reviewed-by: NAndrey Utkin <andrey_utkin@fastmail.com>
Tested-by: NAndrey Utkin <andrey_utkin@fastmail.com>
Tested-by: NAdam Borowski <kilobyte@angband.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This refactoring is in preparation for persistent scrollback
support for VGA console.
Signed-off-by: NManuel Schölling <manuel.schoelling@gmx.de>
Reviewed-by: NAndrey Utkin <andrey_utkin@fastmail.com>
Tested-by: NAndrey Utkin <andrey_utkin@fastmail.com>
Tested-by: NAdam Borowski <kilobyte@angband.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Otherwise the interconnect related code implementing PM runtime will
produce these errors on a failed probe:

omap_uart 48066000.serial: omap_device: omap_device_enable() called from invalid state 1
omap_uart 48066000.serial: use pm_runtime_put_sync_suspend() in driver?

Note that we now also need to check for priv in omap8250_runtime_suspend()
as it has not yet been registered if probe fails. And we need to use
pm_runtime_put_sync() to properly idle the device like we already do
in omap8250_remove().

Fixes: 61929cf0 ("tty: serial: Add 8250-core based omap driver")
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>