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

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

This means we can have

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The driver core clears the driver data to NULL after device_release
or on probe failure. Thus, it is not needed to manually clear the
device driver data to NULL.
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

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

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

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

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

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

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

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

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

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

Commit 9326b047 includes a typo
of "8350_core" instead of "8250_core", so correct it.

Fixes kernel bugzilla #60724:
  https://bugzilla.kernel.org/show_bug.cgi?id=60724Reported-by: NChristoph Biedl <bugzilla.kernel.bpeb@manchmal.in-ulm.de>
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

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

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

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

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

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

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

During resume, a startup will request_irq again, meantime resume function's
enable_irq will cause unbalanced IRQ issue.
Fix this issue by moving request_irq to probe function.
Signed-off-by: NDavid Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: NChen, Jie <jie.d.chen@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With the recent pinctrl-single changes, omaps can treat
wake-up events from deeper idle states as interrupts.

There's a separate "io chain" controller on most omaps
that stays enabled when the device hits off-idle and the
regular interrupt controller is powered off.

Let's add support for the optional second interrupt for
wake-up events. And then serial-omap can manage the
wake-up interrupt from it's runtime PM calls to avoid
spurious interrupts during runtime.

Note that the wake interrupt is board specific as it
uses the UART RX pin, and for omap3, there are six pin
options for UART3 RX pin.

Also Note that the legacy platform based booting handles
the wake-ups in the legacy mux driver and does not need to
pass the wake-up interrupt to the driver.

And finally, to pass the wake-up interrupt in the dts file,
either interrupt-map or the pending interrupts-extended
property needs to be passed. It's probably best to use
interrupts-extended when it's available.

Cc: Felipe Balbi <balbi@ti.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: NFelipe Balbi <balbi@ti.com>
Reviewed-by: NRoger Quadros <rogerq@ti.com>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch removes duplicate defines in drivers/tty/serial/sirfsoc_uart.h
Signed-off-by: NMichael Opdenacker <michael.opdenacker@free-electrons.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clock notifiers are only available when CONFIG_COMMON_CLK is enabled.
Hence all notifier related code has to be protected by corresponsing
ifdefs.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If CONFIG_PM_SLEEP is enabled and CONFIG_SERIAL_XILINX_PS_UART_CONSOLE
is not, a forward declaration of the uart_driver struct is not
included, leading to a build error due to an undeclared variable.
Fixing this by moving the definition of the struct uart_driver before
the definition of the suspend/resume callbacks.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Initialize varibles for which a 'may be used uninitalized' warning is
issued.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Reported-by: Nkbuild test robot <fengguang.wu@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NVinod Koul <vinod.koul@intel.com>

Replace some instances of of_irq_map_one()/irq_create_of_mapping() and
of_irq_to_resource() by the simpler equivalent irq_of_parse_and_map().
Signed-off-by: NThierry Reding <treding@nvidia.com>
Acked-by: NRob Herring <rob.herring@calxeda.com>
[grant.likely: resolved conflicts with core code renames]
Signed-off-by: NGrant Likely <grant.likely@linaro.org>

Signed-off-by: NAngelo Butti <buttiangelo@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implement suspend and resume callbacks in order to support system
suspend/hibernation.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add a clock notifier to dynamically handle frequency changes of the
input clock by reprogramming the UART in order to keep the baud rate
constant.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The original algorithm to find the best baud rate dividers does not necessarily
find the best set of dividers. And in the worst case may even write illegal
values to the hardware.
The new function should make better use of the hardware capabilities and be able
to provide valid settings for a wider range of baud rates and also input clocks.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It is possible that under certain circumstances xuartps_console_write is entered
while the UART disabled. When this happens the code will busy loop in
xuartps_console_putchar, since the character is never written and the TXEMPTY
flag is never set. The result is a system lockup. This patch force enables the
UART for the duration of xuartps_console_write to avoid this.
Signed-off-by: NLars-Peter Clausen <lars@metafoo.de>
Signed-off-by: NJohn Linn <john.linn@xilinx.com>
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Changes to use the 64 byte FIFO depth and fix the issue
by clearing the txempty interrupt in isr status for tx
after filling in data in start_tx function
Signed-off-by: NSuneel Garapati <suneelg@xilinx.com>
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows KDB/KGDB to run.
Signed-off-by: NVlad Lungu <vlad.lungu@windriver.com>
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The Cadence UART does not do break detection, even if the
datasheet says it does. This patch adds break detection in
software (tested in 8N1 mode only) and enables SYSRQ,
allowing for Break-g to enter KDB and all the other goodies.
Signed-off-by: NVlad Lungu <vlad.lungu@windriver.com>
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the device managed interface for memory allocation, simplifying
error paths.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use the device managed interface for clocks, simplifying error paths.
Signed-off-by: NSoren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On older SoC, the "name" field is not filled in the register map.
Fix the way to figure out if the serial port is an uart or an usart for these
older products (with corresponding properties).
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>