Commit f8df13e0 ("tty: Clean console safely") added code to clear
both the scrollback buffer and the screen with "\e[3J", then execution
falls through into the code to simply clear the screen. This means
scr_memsetw() and the console driver update callback are called twice
on the whole screen buffer. Let's reorganize the code so the same work
is not performed twice needlessly.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

UCR4_OREN is (depending on the configuration) enabled in startup,
but is never disabled. Fix this by disabling it in shutdown.
Reported-by: NNandor Han <nandor.han@ge.com>
Signed-off-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

According to Documentation/serial/driver the shutdown function should
not disable RTS, so drop it.
Suggested-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

DMA engine driver might not always provide all the features needed by
serial driver to properly operate in DMA mode, so check that before
selecting DMA mode.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: NKrzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add missing const qualifiers to the parameters of the termios hw-change
helper, which is used by a few USB serial drivers. This specifically
allows the pl2303 driver to use const arguments in one of its helper as
well.

Cc: Jiri Slaby <jslaby@suse.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohan Hovold <johan@kernel.org>

Just set up the show callback in the tty_operations, and use
proc_create_single_data to create the file without additional
boilerplace code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Variants of proc_create{,_data} that directly take a struct seq_operations
argument and drastically reduces the boilerplate code in the callers.

All trivial callers converted over.
Signed-off-by: NChristoph Hellwig <hch@lst.de>

Unlike normal serials, in pty layer, there is no guarantee that multiple
threads don't insert input characters at the same time. If it is happened,
tty_insert_flip_string_fixed_flag can be executed concurrently. This can
lead slab out-of-bounds write in tty_insert_flip_string_fixed_flag.

Call sequences are as follows.
CPU0                                    CPU1
n_tty_ioctl_helper                      n_tty_ioctl_helper
__start_tty                             tty_send_xchar
tty_wakeup                              pty_write
n_hdlc_tty_wakeup                       tty_insert_flip_string
n_hdlc_send_frames                      tty_insert_flip_string_fixed_flag
pty_write
tty_insert_flip_string
tty_insert_flip_string_fixed_flag

To fix the race, acquire port->lock in pty_write() before it inserts input
characters to tty buffer. It prevents multiple threads from inserting
input characters concurrently.

The crash log is as follows:
BUG: KASAN: slab-out-of-bounds in tty_insert_flip_string_fixed_flag+0xb5/
0x130 drivers/tty/tty_buffer.c:316 at addr ffff880114fcc121
Write of size 1792 by task syz-executor0/30017
CPU: 1 PID: 30017 Comm: syz-executor0 Not tainted 4.8.0 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.8.2-0-g33fbe13 by qemu-project.org 04/01/2014
 0000000000000000 ffff88011638f888 ffffffff81694cc3 ffff88007d802140
 ffff880114fcb300 ffff880114fcc300 ffff880114fcb300 ffff88011638f8b0
 ffffffff8130075c ffff88011638f940 ffff88007d802140 ffff880194fcc121
Call Trace:
 __dump_stack lib/dump_stack.c:15 [inline]
 dump_stack+0xb3/0x110 lib/dump_stack.c:51
 kasan_object_err+0x1c/0x70 mm/kasan/report.c:156
 print_address_description mm/kasan/report.c:194 [inline]
 kasan_report_error+0x1f7/0x4e0 mm/kasan/report.c:283
 kasan_report+0x36/0x40 mm/kasan/report.c:303
 check_memory_region_inline mm/kasan/kasan.c:292 [inline]
 check_memory_region+0x13e/0x1a0 mm/kasan/kasan.c:299
 memcpy+0x37/0x50 mm/kasan/kasan.c:335
 tty_insert_flip_string_fixed_flag+0xb5/0x130 drivers/tty/tty_buffer.c:316
 tty_insert_flip_string include/linux/tty_flip.h:35 [inline]
 pty_write+0x7f/0xc0 drivers/tty/pty.c:115
 n_hdlc_send_frames+0x1d4/0x3b0 drivers/tty/n_hdlc.c:419
 n_hdlc_tty_wakeup+0x73/0xa0 drivers/tty/n_hdlc.c:496
 tty_wakeup+0x92/0xb0 drivers/tty/tty_io.c:601
 __start_tty.part.26+0x66/0x70 drivers/tty/tty_io.c:1018
 __start_tty+0x34/0x40 drivers/tty/tty_io.c:1013
 n_tty_ioctl_helper+0x146/0x1e0 drivers/tty/tty_ioctl.c:1138
 n_hdlc_tty_ioctl+0xb3/0x2b0 drivers/tty/n_hdlc.c:794
 tty_ioctl+0xa85/0x16d0 drivers/tty/tty_io.c:2992
 vfs_ioctl fs/ioctl.c:43 [inline]
 do_vfs_ioctl+0x13e/0xba0 fs/ioctl.c:679
 SYSC_ioctl fs/ioctl.c:694 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685
 entry_SYSCALL_64_fastpath+0x1f/0xbd
Signed-off-by: NDaeRyong Jeong <threeearcat@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The GENI serial driver handled transmit by leaving stuff in the
common circular buffer until it had completely caught up to the head,
then clearing it out all at once. This is a suboptimal way to do
transmit, as it leaves data in the circular buffer that could be
freed. Moreover, the logic implementing it is wrong, and it is easy to
get into a situation where the UART infinitely writes out the same buffer.

I could reproduce infinite serial output of the same buffer by running
dmesg, then hitting Ctrl-C. I believe what happened is xmit_size was
something large, marching towards a larger value. Then the generic OS
code flushed out the buffer and replaced it with two characters. Now the
xmit_size is a large value marching towards a small value, which it wasn't
expecting. The driver subtracts xmit_size (very large) from
uart_circ_chars_pending (2), underflows, and repeats ad nauseum. The
locking isn't wrong here, as the locks are held whenever the buffer is
manipulated, it's just that the driver wasn't expecting the buffer to be
flushed out from underneath it in between transmits.

This change reworks transmit to grab what it can from the circular buffer,
and then update ->tail, both fixing the underflow and freeing up space
for a smoother circular experience.
Signed-off-by: NEvan Green <evgreen@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using kgdb, you get an abort when accessing the UART registers.
This is because the driver has already entered runtime PM and so turned
off the bus clock needed to access the registers.

To fix this, set the capability indicating Runtime PM is active while idle.
Signed-off-by: NPhil Edworthy <phil.edworthy@renesas.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

I noticed that unused UARTs won't necessarily idle properly always
unless at least one byte tx transfer is done first.

After some debugging I narrowed down the problem to the scr register
dma configuration bits that need to be set before softreset for the
clocks to idle. Unless we do this, the module clkctrl idlest bits
may be set to 1 instead of 3 meaning the clock will never idle and
is blocking deeper idle states for the whole domain.

This might be related to the configuration done by the bootloader
or kexec booting where certain configurations cause the 8250 or
the clkctrl clock to jam in a way where setting of the scr bits
and reset is needed to clear it. I've tried diffing the 8250
registers for the various modes, but did not see anything specific.
So far I've only seen this on omap4 but I'm suspecting this might
also happen on the other clkctrl using SoCs considering they
already have a quirk enabled for UART_ERRATA_CLOCK_DISABLE.

Let's fix the issue by configuring scr before reset for basic dma
even if we don't use it. The scr register will be reset when we do
softreset few lines after, and we restore scr on resume. We should
do this for all the SoCs with UART_ERRATA_CLOCK_DISABLE quirk flag
set since the ones with UART_ERRATA_CLOCK_DISABLE are all based
using clkctrl similar to omap4.

Looks like both OMAP_UART_SCR_DMAMODE_1 | OMAP_UART_SCR_DMAMODE_CTL
bits are needed for the clkctrl to idle after a softreset.

And we need to add omap4 to also use the UART_ERRATA_CLOCK_DISABLE
for the related workaround to be enabled. This same compatible
value will also be used for omap5.

Fixes: cdb929e4 ("serial: 8250_omap: workaround errata around idling UART after using DMA")
Cc: Keerthy <j-keerthy@ti.com>
Cc: Matthijs van Duin <matthijsvanduin@gmail.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

QCA MIPS support is being converted to pure OF. As part of this we are
dropping the SOC_AR* symbols. Additionally the SERIAL_AR933X style tty
is also found on a few SoCs newer that the AR933x.

This patch changes the dependency to ATH79, thus fixing the 2 issues
described above.
Signed-off-by: NJohn Crispin <john@phrozen.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The Altera 16550 UART core supports FCR Rx Trigger Level setting,
but the port definition in the driver is missing the rxtrig_bytes
array specifying the trigger levels. Add the array to make the Rx
Trigger Level setting available on this type of 16550 UART.
Signed-off-by: NMarek Vasut <marex@denx.de>
Cc: Thor Thayer <tthayer@opensource.altera.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The "unthrottle_timeout" is HZ/10 but mod_timer() takes a the actual
jiffie where you want it to timeout, not an offset.

Fixes: 5909c0bf ("serial/aspeed-vuart: Implement quick throttle mechanism")
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Acked-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 40f70c03 ("serial: sh-sci: add locking to console write
function to avoid SMP lockup") copied the strategy to avoid locking
problems in conjuncture with the console from the UART8250
driver. Instead using directly spin_{try}lock_irqsave(),
local_irq_save() followed by spin_{try}lock() was used. While this is
correct on mainline, for -rt it is a problem. spin_{try}lock() will
check if it is running in a valid context. Since the local_irq_save()
has already been executed, the context has changed and
spin_{try}lock() will complain. The reason why spin_{try}lock()
complains is that on -rt the spin locks are turned into mutexes and
therefore can sleep. Sleeping with interrupts disabled is not valid.

BUG: sleeping function called from invalid context at /home/wagi/work/rt/v4.4-cip-rt/kernel/locking/rtmutex.c:995
in_atomic(): 0, irqs_disabled(): 128, pid: 778, name: irq/76-eth0
CPU: 0 PID: 778 Comm: irq/76-eth0 Not tainted 4.4.126-test-cip22-rt14-00403-gcd03665c8318 #12
Hardware name: Generic RZ/G1 (Flattened Device Tree)
Backtrace:
[<c00140a0>] (dump_backtrace) from [<c001424c>] (show_stack+0x18/0x1c)
 r7:c06b01f0 r6:60010193 r5:00000000 r4:c06b01f0
[<c0014234>] (show_stack) from [<c01d3c94>] (dump_stack+0x78/0x94)
[<c01d3c1c>] (dump_stack) from [<c004c134>] (___might_sleep+0x134/0x194)
 r7:60010113 r6:c06d3559 r5:00000000 r4:ffffe000
[<c004c000>] (___might_sleep) from [<c04ded60>] (rt_spin_lock+0x20/0x74)
 r5:c06f4d60 r4:c06f4d60
[<c04ded40>] (rt_spin_lock) from [<c02577e4>] (serial_console_write+0x100/0x118)
 r5:c06f4d60 r4:c06f4d60
[<c02576e4>] (serial_console_write) from [<c0061060>] (call_console_drivers.constprop.15+0x10c/0x124)
 r10:c06d2894 r9:c04e18b0 r8:00000028 r7:00000000 r6:c06d3559 r5:c06d2798
 r4:c06b9914 r3:c02576e4
[<c0060f54>] (call_console_drivers.constprop.15) from [<c0062984>] (console_unlock+0x32c/0x430)
 r10:c06d30d8 r9:00000028 r8:c06dd518 r7:00000005 r6:00000000 r5:c06d2798
 r4:c06d2798 r3:00000028
[<c0062658>] (console_unlock) from [<c0062e1c>] (vprintk_emit+0x394/0x4f0)
 r10:c06d2798 r9:c06d30ee r8:00000006 r7:00000005 r6:c06a78fc r5:00000027
 r4:00000003
[<c0062a88>] (vprintk_emit) from [<c0062fa0>] (vprintk+0x28/0x30)
 r10:c060bd46 r9:00001000 r8:c06b9a90 r7:c06b9a90 r6:c06b994c r5:c06b9a3c
 r4:c0062fa8
[<c0062f78>] (vprintk) from [<c0062fb8>] (vprintk_default+0x10/0x14)
[<c0062fa8>] (vprintk_default) from [<c009cd30>] (printk+0x78/0x84)
[<c009ccbc>] (printk) from [<c025afdc>] (credit_entropy_bits+0x17c/0x2cc)
 r3:00000001 r2:decade60 r1:c061a5ee r0:c061a523
 r4:00000006
[<c025ae60>] (credit_entropy_bits) from [<c025bf74>] (add_interrupt_randomness+0x160/0x178)
 r10:466e7196 r9:1f536000 r8:fffeef74 r7:00000000 r6:c06b9a60 r5:c06b9a3c
 r4:dfbcf680
[<c025be14>] (add_interrupt_randomness) from [<c006536c>] (irq_thread+0x1e8/0x248)
 r10:c006537c r9:c06cdf21 r8:c0064fcc r7:df791c24 r6:df791c00 r5:ffffe000
 r4:df525180
[<c0065184>] (irq_thread) from [<c003fba4>] (kthread+0x108/0x11c)
 r10:00000000 r9:00000000 r8:c0065184 r7:df791c00 r6:00000000 r5:df791d00
 r4:decac000
[<c003fa9c>] (kthread) from [<c00101b8>] (ret_from_fork+0x14/0x3c)
 r8:00000000 r7:00000000 r6:00000000 r5:c003fa9c r4:df791d00

Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NDaniel Wagner <daniel.wagner@siemens.com>
Reviewed-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently the 8250_of driver only supports MEM IO type
accesses.

Some development boards (Huawei D03, specifically) require
IO space access for 8250-compatible OF driver support, so
add it.

The modification is quite simple: just set the port iotype
and associated flags depending on the device address
resource type.
Signed-off-by: NJohn Garry <john.garry@huawei.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

I was puzzled while looking at /proc/interrupts and random things showed
up between reboots. This occurred more often but I realised it later. The
"correct" output should be:
|38:      11861  atmel-aic5   2 Level     ttyS0

but I saw sometimes
|38:       6426  atmel-aic5   2 Level     tty1

and accounted it wrongly as correct. This is use after free and the
former example randomly got the "old" pointer which pointed to the same
content. With SLAB_FREELIST_RANDOM and HARDENED I even got
|38:       7067  atmel-aic5   2 Level     E=Started User Manager for UID 0

or other nonsense.
As it turns out the tty, pointer that is accessed in atmel_startup(), is
freed() before atmel_shutdown(). It seems to happen quite often that the
tty for ttyS0 is allocated and freed while ->shutdown is not invoked. I
don't do anything special - just a systemd boot :)

Use dev_name(&pdev->dev) as the IRQ name for request_irq(). This exists
as long as the driver is loaded so no use-after-free here.

Cc: stable@vger.kernel.org
Fixes: 761ed4a9 ("tty: serial_core: convert uart_close to use tty_port_close")
Acked-by: NRichard Genoud <richard.genoud@gmail.com>
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This properly unmaps DMA SG on device shutdown.
Reported-by: NNandor Han <nandor.han@ge.com>
Suggested-by: NNandor Han <nandor.han@ge.com>
Signed-off-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove unrelated CTSC/CTS disabling from imx_uart_disable_dma() and
move it to imx_uart_shutdown(), which is the only user of the DMA
disabling function. This should not change the driver's behaviour,
but improves readability. After this change imx_uart_disable_dma()
does the reverse thing of imx_uart_enable_dma().
Suggested-by: NNandor Han <nandor.han@ge.com>
Signed-off-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add early console support in Qualcomm Technologies Inc., GENI based
UART controller.
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Signed-off-by: NGirish Mahadevan <girishm@codeaurora.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently the driver returns IRQ_HANDLED when spurious interrupts happen.
This is misleading. Fix the behavior by returning IRQ_NONE for spurious
interrupts.
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: NMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use iowrite32_rep to write to the hardware FIFO so that the code does
not have to worry about the system endianness.
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: NMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

While initiating TX, only the register reads need to be ordered. The
register write order either is achieved due to data dependency or is
not required.

Use readl to achieve the read order and remove the unnecessary barrier.
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: NEvan Green <evgreen@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Perform static initialization of console_port since its initial state has
no run-time dependencies.
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: NMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use min3 helper to calculate the minimum value of 3 variables.
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: NMatthias Kaehlcke <mka@chromium.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* Remove redundant casting while using min_t
* Remove redundant initialization of port_setup flag
* Remove redundant error checking in get_tx_fifo_size
* Remove logging redundant error code in debug messages
* Remove redundant disable_irq before free_irq
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

* Document reason for newline character counting in console_write
* Document reason for disabling IRQ in the system resume operation
Signed-off-by: NKarthikeyan Ramasubramanian <kramasub@codeaurora.org>
Reviewed-by: NMatthias Kaehlcke <mka@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The best granularity of residue that DMA engine can report is in the BURST
units, so the serial driver must use MAXBURST = 1 and DMA_SLAVE_BUSWIDTH_1_BYTE
if it relies on exact number of bytes transferred by DMA engine.

Fixes: 62c37eed ("serial: samsung: add dma reqest/release functions")
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NKrzysztof Kozlowski <krzk@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As stated under "20) Conditional Compilation" in coding-style.rst. We
shall rather use __maybe_unused than preprocessor macros in such cases.
Signed-off-by: NPascal Huerst <pascal.huerst@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no reason to initialize uartclk to BASE_BAUD * 16 for DT based
systems.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Tested-by: NMatt Redfearn <matt.redfearn@mips.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 9b96fbac ("serial: PL011: clear pending interrupts")
clears the RX and receive timeout interrupts on pl011 startup, to
avoid a screaming-interrupt scenario that can occur when the
firmware or bootloader leaves these interrupts asserted.

This has been noted as an issue when running Linux on qemu [1].

Unfortunately, the above fix seems to lead to potential
misbehaviour if the RX FIFO interrupt is asserted _non_ spuriously
on driver startup, if the RX FIFO is also already full to the
trigger level.

Clearing the RX FIFO interrupt does not change the FIFO fill level.
In this scenario, because the interrupt is now clear and because
the FIFO is already full to the trigger level, no new assertion of
the RX FIFO interrupt can occur unless the FIFO is drained back
below the trigger level.  This never occurs because the pl011
driver is waiting for an RX FIFO interrupt to tell it that there is
something to read, and does not read the FIFO at all until that
interrupt occurs.

Thus, simply clearing "spurious" interrupts on startup may be
misguided, since there is no way to be sure that the interrupts are
truly spurious, and things can go wrong if they are not.

This patch instead clears the interrupt condition by draining the
RX FIFO during UART startup, after clearing any potentially
spurious interrupt.  This should ensure that an interrupt will
definitely be asserted if the RX FIFO subsequently becomes
sufficiently full.

The drain is done at the point of enabling interrupts only.  This
means that it will occur any time the UART is newly opened through
the tty layer.  It will not apply to polled-mode use of the UART by
kgdboc: since that scenario cannot use interrupts by design, this
should not matter.  kgdboc will interact badly with "normal" use of
the UART in any case: this patch makes no attempt to paper over
such issues.

This patch does not attempt to address the case where the RX FIFO
fills faster than it can be drained: that is a pathological
hardware design problem that is beyond the scope of the driver to
work around.  As a failsafe, the number of poll iterations for
draining the FIFO is limited to twice the FIFO size.  This will
ensure that the kernel at least boots even if it is impossible to
drain the FIFO for some reason.

[1] [Qemu-devel] [Qemu-arm] [PATCH] pl011: do not put into fifo
before enabled the interruption
https://lists.gnu.org/archive/html/qemu-devel/2018-01/msg06446.htmlReported-by: NWei Xu <xuwei5@hisilicon.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Peter Maydell <peter.maydell@linaro.org>
Fixes: 9b96fbac ("serial: PL011: clear pending interrupts")
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Cc: stable <stable@vger.kernel.org>
Tested-by: NWei Xu <xuwei5@hisilicon.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

syzbot is reporting crashes triggered by memory allocation fault injection
at tty_ldisc_get() [1]. As an attempt to handle OOM in a graceful way, we
have tried commit 5362544b ("tty: don't panic on OOM in
tty_set_ldisc()"). But we reverted that attempt by commit a8983d01
("Revert "tty: don't panic on OOM in tty_set_ldisc()"") due to reproducible
crash. We should spend resource for finding and fixing race condition bugs
rather than complicate error paths for 2 * sizeof(void *) bytes allocation
failure.

[1] https://syzkaller.appspot.com/bug?id=489d33fa386453859ead58ff5171d43772b13aa3Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Nsyzbot <syzbot+40b7287c2dc987c48c81@syzkaller.appspotmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vegard Nossum <vegard.nossum@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Allocate uart port structure dynamically.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

c&p this function to probe as preparation for removing
cdns_uart_port[] static array.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Driver console functions are using pointer to static array with fixed
size. There can be only one serial console at the time which is found
by register_console(). register_console() is filling cons->index to
port->line value.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

register_console() is called from
uart_add_one_port()->uart_configure_port()
that's why register_console() is called twice.

This patch remove console_initcall to call register_console() only from
one location.

Also based on my tests cdns_uart_console_setup() is not called
from the first register_console() call.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Reviewed-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the clock is enabled, check if there is an error. Otherwise
clk_get_rate() can be called without enabled clock.

Found by Linux Driver Verification project (linuxtesting.org).

Fixes: 0814e8d5 ("sc16is7xx: enable the clock")
Signed-off-by: NStefan Potyra <Stefan.Potyra@elektrobit.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The method ndo_start_xmit() is defined as returning an 'netdev_tx_t',
which is a typedef for an enum type, but the implementation in this
driver returns an 'int'.

Fix this by returning 'netdev_tx_t' in this driver too.
Signed-off-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

device->baud is always non zero value because it is checked already in
early_serial8250_setup() before init_port is called.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Correct misaligned indentation and remove extraneous spaces.
Signed-off-by: NJoey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>