tty.h is large enough currently. And I am slowly adding kernel-doc
documentation, so it grows to unmaintainable long mess. To avoid this,
split tty.h further into tty_buffer.h and move there tty_buffer-related
declarations and function prototypes.

Note that many of the tty_buffer.c function prototypes reside now in
tty_flip.h. But we cannot move struct tty_buffer & friends because:
* tty_insert_flip_char() in tty_flip.h needs both struct tty_port and
  struct tty_buffer defined.
* struct tty_port in tty_port.h needs struct tty_buffer defined.

So if we moved struct tty_buffer to tty_flip.h too, tty_flip.h would
need tty_port.h and that would need tty_flip.h (to have tty_buffer)
again. Hence we introduce new header tty_buffer.h here to break this
circular dependency.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-7-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

It's the only remaining tty_buffer.c prototype residing in tty.h. Move
it along others to tty_flip.h.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-6-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We use structs list_head and lockdep_map as non-pointers in tty_ldisc.h.
So better have headers defining them explicitly included so that the
structs are always defined. Not only implicitly via random include
chains.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-5-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We already have tty_ldisc.h, so cleanup tty.h a bit by moving out
tty_ldisc-related function prototypes and a variable into tty_ldisc.h.
They are implemented in tty_ldisc.c anyway.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-4-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We use kref in tty_driver.h, but do not include kref.h. It is currently
included by linux/cdev.h -> linux/kobject.h -> linux/kref.h chain, so
everything is in order only implicitly. So make this dependency
explicit.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-3-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

We already have tty_driver.h, so cleanup tty.h a bit by moving out
tty_driver-related function prototypes into tty_driver.h.

Note that tty.h already includes tty_driver.h.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210723103147.18250-2-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to have an extra pointer to a string (v253_init).
Convert it to an array.

Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210722115141.516-2-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

TTY layer does nothing if tty_ldisc_ops::write_wakeup is NULL, so there
is no need to implement an empty one in cx20442. Drop it.

Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>
Cc: Takashi Iwai <tiwai@suse.com>
Cc: alsa-devel@alsa-project.org
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210722115141.516-1-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Dennis reported that on ACPI-based systems the clock frequency
isn't enough to configure device properly. We have to respect
the clock source as well. To achieve this match the clock-names
property against "osc" to recognize external clock connection.
On DT-based system this doesn't change anything.
Reported-and-tested-by: Dennis Giaya <dgiaya@whoi.edu>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210723125943.22039-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

PSE UARTs on Intel Elkhart Lake support DMA mode.
Enable DMA on these ports.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210721162452.48764-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The Intel IXP425 Vulcan board has an Exar XR16L2551 8250-compatible.
It works like an 8250 but it is always good to specify exactly which
component we are using. This allows us to specify:

compatible = "exar,xr16l2551", "ns8250";

Put in some sibling Exar serial compatibles while we're at it.

Cc: Marc Zyngier <maz@kernel.org>
Cc: devicetree@vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210716225319.1282704-1-linus.walleij@linaro.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Oxford Semiconductor 950 serial port devices have a 128-byte FIFO and in
the enhanced (650) mode, which we select in `autoconfig_has_efr' with
the ECB bit set in the EFR register, they support the receive interrupt
trigger level selectable with FCR bits 7:6 from the set of 16, 32, 112,
120.  This applies to the original OX16C950 discrete UART[1] as well as
950 cores embedded into more complex devices.

For these devices we set the default to 112, which sets an excessively
high level of 112 or 7/8 of the FIFO capacity, unlike with other port
types where we choose at most 1/2 of their respective FIFO capacities.
Additionally we don't make the trigger level configurable.  Consequently
frequent input overruns happen with high bit rates where hardware flow
control cannot be used (e.g. terminal applications) even with otherwise
highly-performant systems.

Lower the default receive interrupt trigger level to 32 then, and make
it configurable.  Document the trigger levels along with other port
types, including the set of 16, 32, 64, 112 for the transmit interrupt
as well[2].

References:

[1] "OX16C950 rev B High Performance UART with 128 byte FIFOs", Oxford
    Semiconductor, Inc., DS-0031, Sep 05, Table 10: "Receiver Trigger
    Levels", p. 22

[2] same, Table 9: "Transmit Interrupt Trigger Levels", p. 22
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260608480.37803@angie.orcam.me.ukSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Xen frontends shouldn't BUG() in case of illegal data received from
their backends. So replace the BUG_ON()s when reading illegal data from
the ring page with negative return values.
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210707091045.460-1-jgross@suse.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

'state' variable is only set but never read in amiserial's shutdown.
Drop it.

It was like this since the driver was added to the tree as far as I can
tell.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-11-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

amiserial deals only with a single serial, so drop the rs_table array
and NR_PORTS and define a single non-array serial_state for simplicity
instead.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-10-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The #include directives are in different places in amiserial:
1) there is no reason for that, and
2) it makes hard to judge what is included and what is not.

Therefore, move all the includes to a single place and sort them.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-9-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

"custom" macro is a too generic name. Expand it -- that is use
amiga_custom on all the locations.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-8-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Having a macro (serial_isroot) for capable(CAP_SYS_ADMIN) does not save
us from anything. It rather obfuscates the code. Hence expand
serial_isroot to be explicit like every other driver is.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-7-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Zeroing each member of struct serial_state in probe is fragile and
overly complicated. Do one memset for them all.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-6-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

tty->port is already set when rs_open is called given we linked it by
tty_port_link_device(). If it wasn't, the tty layer would WARN loudly.
So it's pointless to set it in rs_open. Instead, use the value in
tty->port to find out the serial_state (info).

It's a fallout of commit b19e2ca7 (TTY: use tty_port_link_device)
which added tty_port_link_device here, but omitted to remove the
tty->port assignment from rs_open.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-5-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

It's always 1, so define a macro for it instead. Note that the check in
set_serial_info is doubled, hence remove the latter.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-4-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The comment about interrupt routines is stale at least since commit
41c28ff1 (kill _INLINE_) from 2006. So remove the obsolete parts and
leave only "here they start...".
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-3-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove a print of serial_name and serial_version from the probe
function, i.e. show_serial_version() from amiga_serial_probe(). The
value of such a print is minimal.

Aside from that, the version is artificial (copied from the serial core
in 2.3.45pre2 and never increased). So inline the version into
seq_printf's format string in rs_proc_show() and remove both strings
completely.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-2-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The ugly DBG_CNT macro is unused, so remove.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210714091314.8292-1-jslaby@suse.czSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

For the sake of reducing layering violation add ->unregister_gpio()
callback and use it in the ->exit() one.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20210713095821.7834-1-andriy.shevchenko@linux.intel.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is a spelling mistake in the Kconfig text. Fix it.
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210719102421.14813-1-colin.king@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert serial for Cadence UART bindings documentation to YAML.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
Link: https://lore.kernel.org/r/20210715092252.225740-1-iwamatsu@nigauri.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In the commit 07e5d4ff ("Revert serial-uartlite: Add runtime
support") the runtime pm support was reverted to aid reverting of
the other patches.

This patch adds the runtime PM support back.
The runtime pm calls are used to gate and enable the clocks.
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/20210713064835.27978-3-shubhrajyoti.datta@xilinx.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In case the uart registration fails the clocks are left enabled.
Disable the clock in case of errors.
Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Link: https://lore.kernel.org/r/20210713064835.27978-2-shubhrajyoti.datta@xilinx.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This issue happens when a userspace program does an ioctl
FBIOPUT_VSCREENINFO passing the fb_var_screeninfo struct
containing only the fields xres, yres, and bits_per_pixel
with values.

If this struct is the same as the previous ioctl, the
vc_resize() detects it and doesn't call the resize_screen(),
leaving the fb_var_screeninfo incomplete. And this leads to
the updatescrollmode() calculates a wrong value to
fbcon_display->vrows, which makes the real_y() return a
wrong value of y, and that value, eventually, causes
the imageblit to access an out-of-bound address value.

To solve this issue I made the resize_screen() be called
even if the screen does not need any resizing, so it will
"fix and fill" the fb_var_screeninfo independently.

Cc: stable <stable@vger.kernel.org> # after 5.15-rc2 is out, give it time to bake
Reported-and-tested-by: syzbot+858dc7a2f7ef07c2c219@syzkaller.appspotmail.com
Signed-off-by: Igor Matheus Andrade Torrente <igormtorrente@gmail.com>
Link: https://lore.kernel.org/r/20210628134509.15895-1-igormtorrente@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When DMA is used for TX and RX by serial driver, it should
pass the DMA device pointer to DMA API instead of UART device
pointer. DMA device should be used for DMA API because only
the DMA device is aware of how the device connects to the memory.
There might be an extra level of address translation due to a
SMMU attached to the DMA device. When serial device is used for
DMA API, the DMA API will have no clue of the SMMU attached to
the DMA device.

This patch is necessary to fix the SMMU page faults
which is observed when a DMA(with SMMU enabled) is attached
to UART for transfer.
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Tamseel Shams <m.shams@samsung.com>
Signed-off-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Link: https://lore.kernel.org/r/20210629045902.48912-1-m.shams@samsung.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In order to make pl011 work better, multiple interrupts are
required, such as TXIM, RXIM, RTIM, error interrupt(FE/PE/BE/OE);
at the same time, pl011 to GIC does not merge the interrupt
lines(each serial-interrupt corresponding to different GIC hardware
interrupt), so need to enable and request multiple gic interrupt
numbers in the driver.
Signed-off-by: Bing Fan <tombinfan@tencent.com>
Link: https://lore.kernel.org/r/1625103512-30182-1-git-send-email-hptsfb@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add basic support for RS485: Provide a callback to configure RS485
settings. Handle the RS485 specific part in the functions
pl011_rs485_tx_start() and pl011_rs485_tx_stop() which extend the generic
start/stop callbacks.
Beside via IOCTL from userspace RS485 can be enabled by means of the
device tree property "rs485-enabled-at-boot-time".
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Link: https://lore.kernel.org/r/20210630225644.3744-1-LinoSanfilippo@gmx.deSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

uart_handle_dcd_change() requires a port lock to be held and will emit a
warning when lockdep is enabled.

Held corresponding lock to fix the following warnings.

[  132.528648] WARNING: CPU: 5 PID: 11600 at drivers/tty/serial/serial_core.c:3046 uart_handle_dcd_change+0xf4/0x120
[  132.530482] Modules linked in:
[  132.531050] CPU: 5 PID: 11600 Comm: jsm Not tainted 5.14.0-rc1-00003-g7fef2edf-dirty #31
[  132.535268] RIP: 0010:uart_handle_dcd_change+0xf4/0x120
[  132.557100] Call Trace:
[  132.557562]  ? __free_pages+0x83/0xb0
[  132.558213]  neo_parse_modem+0x156/0x220
[  132.558897]  neo_param+0x399/0x840
[  132.559495]  jsm_tty_open+0x12f/0x2d0
[  132.560131]  uart_startup.part.18+0x153/0x340
[  132.560888]  ? lock_is_held_type+0xe9/0x140
[  132.561660]  uart_port_activate+0x7f/0xe0
[  132.562351]  ? uart_startup.part.18+0x340/0x340
[  132.563003]  tty_port_open+0x8d/0xf0
[  132.563523]  ? uart_set_options+0x1e0/0x1e0
[  132.564125]  uart_open+0x24/0x40
[  132.564604]  tty_open+0x15c/0x630
Signed-off-by: Zheyu Ma <zheyuma97@gmail.com>
Link: https://lore.kernel.org/r/1626242003-3809-1-git-send-email-zheyuma97@gmail.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Report extra baud rates supported above the base rate for ports with the
UPF_MAGIC_MULTIPLIER property, so that people have a way to find out
that they can be used with their system, e.g.:

Serial: 8250/16550 driver, 5 ports, IRQ sharing enabled
printk: console [ttyS0] disabled
serial8250.0: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
serial8250.0: ttyS0 extra baud rates supported: 230400, 460800
printk: console [ttyS0] enabled
printk: bootconsole [uart8250] disabled
serial8250.0: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
serial8250.0: ttyS1 extra baud rates supported: 230400, 460800
serial8250.0: ttyS2 at MMIO 0x1f000900 (irq = 20, base_baud = 230400) is a 16550A

Otherwise there is no clear way to figure this out, as the feature is
only reported as an obscure TTY flag in bit 16:

$ cat /sys/class/tty/ttyS[0-2]/flags
0x10010040
0x10010040
0x90000040
$
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260334170.37803@angie.orcam.me.ukSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Allow more drivers to be compile tested more easily, for example, when
doing subsystem-wide changes.

Verified on X86_64 as well as arm, powerpc and m68k with minimal configs
in order to catch missing implicit build dependencies.
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20210715083011.18887-1-johan@kernel.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pointer membase is currently being in initialized with zero rather
than NULL. Fix this.
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210719095533.14017-1-colin.king@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

ACPI-based Loongson boards need configurable rather than fixed clock
frequency for serial ports.
Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
Link: https://lore.kernel.org/r/20210715061637.134436-1-chenhuacai@loongson.cnSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Don't populate the const array k3_soc_devices on the stack but instead it
static. Makes the object code smaller by 44 bytes:

Before:
   text    data     bss     dec     hex filename
  31628    5609     128   37365    91f5 drivers/tty/serial/8250/8250_omap.o

After:
   text    data     bss     dec     hex filename
  31520    5673     128   37321    91c9 drivers/tty/serial/8250/8250_omap.o
Reduction of 44 bytes

(gcc version 10.3.0)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210715140759.27244-1-colin.king@canonical.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>