This change teaches the imx serial driver to save its
context and restore it across suspend and resume path.
To do so, it introduces serial_imx_restore_context()
and serial_imx_save_context() functions. They use
a shadow set of registers to save key registers
and restore them accordingly. These functions can
be reused on other situations, when the device
context is lost.

Cc: Fabio Estevam <festevam@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch sets RTSDEN bit when going into idle (Stop mode).
We add the RTSDEN for the case RTS is sent from
the remote connection. This way we allow the system
to wakeup when RTS is received.

Cc: Fabio Stevam <festevam@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This change is a code reorganization. Here we introduce
serial_imx_enable_wakeup() helper function to do
the job of configuring and preparing wakeup sources
on imx serial device. The idea is to allow other
parts of the code to call this function whenever
the device is known to go to idle.

Cc: Fabio Estevam <festevam@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The current code attempts to prepare clk_per and clk_ipg
before using the device. However, the result is an extra
prepare call on each clock. Here is the output of uart
clocks (only uart enabled and used as console):

$  grep uart /sys/kernel/debug/clk/clk_summary
 uart_serial           1            2    80000000          0 0
       uart           1            2    66000000          0 0

This patch balances the calls of prepares. The result is:

$  grep uart /sys/kernel/debug/clk/clk_summary
 uart_serial           1            1    80000000          0 0
       uart           1            1    66000000          0 0

Cc: Fabio Estevam <festevam@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: NEduardo Valentin <edubezval@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

That bitfield is modified by read + or + write operation. If someone
sets any of the other two bits it might render the lock useless.

While at it, remove other bitfields as well to avoid more such
errors.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJohn Ogness <john.ogness@linutronix.de>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The 8250-omap driver requires the DMA-engine driver to support the pause
command in order to properly turn off programmed RX transfer before the
driver stars manually reading from the FIFO.
The lacking support of the requirement has been discovered recently. In
order to stay safe here we disable RX-DMA completly on probe.
The rx_dma_broken assignment on probe could be removed once we working
pause function in omap-dma.

Cc: <stable@vger.kernel.org>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since the serial core is informed that this device is doing
automatic flow control, it is not necessary to alter CTS and
DCTS of the MSR as the core no longer attempts stop the port
in uart_handle_cts_change().
Signed-off-by: NHuiquan Zhong <huiquan.zhong@intel.com>
Signed-off-by: NQipeng Zha <qipeng.zha@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

port->lock get's initialized in uart_add_one_port(), no need to do it
in men_z135_probe().
Signed-off-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix panic caused by a race between men_z135_intr() and men_z135_set_termios().

men_z135_intr() and men_z135_set_termios() both hold the struct uart_port::lock
spinlock, but men_z135_intr() does a spin_lock_irqsave() and
men_z135_set_termios() does a normal spin_lock(), which can lead to a deadlock
when an interrupt is called while the lock is being helt by
men_z135_set_termios().

This was discovered using a insmod, hardware looppback send/receive, rmmod
stress test.
Signed-off-by: NJohannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Cc: Andreas Werner <andreas.werner@men.de>
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This way this device can be used with irtty-sir -
at least on Toshiba Satellite A20-S103 it is not configured by default
and needs PNP activation before it starts to respond on I/O ports.

This device has actually its own driver (ali-ircc),
but this driver seems to be non-functional for a very long time
(see http://permalink.gmane.org/gmane.linux.irda.general/484
http://permalink.gmane.org/gmane.network.protocols.obex.openobex.user/943
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=535070 ).
Signed-off-by: NMaciej Szmigiero <mail@maciej.szmigiero.name>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

SMSC IrCC SIR/FIR port should not be bound to by
(legacy) serial driver so its own driver (smsc-ircc2)
can bind to it.
Signed-off-by: NMaciej Szmigiero <mail@maciej.szmigiero.name>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently mxs-auart doesn't care correctly about the baud rate divisor.
According to reference manual the baud rate divisor must be between
0x000000EC and 0x003FFFC0. So calculate the possible baud rate range
and use it for uart_get_baud_rate().
Signed-off-by: NStefan Wahren <stefan.wahren@i2se.com>
Reviewed-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Whenever the UART device driver gets closed from userland, the driver
disables the UART unit and then stops the clocks to save power.

The bit which disabled the UART unit is described as:

 "UART Enable. If this bit is set to 1, the UART is enabled. Data
  transmission and reception occurs for the UART signals. When the
  UART is disabled in the middle of transmission or reception, it
  completes the current character before stopping."

The important part is the "it completes the current character". Whenever
a reception is ongoing when the UART gets disabled (including the clock
off) the statemachine freezes and "remembers" this state on the next
open() when re-enabling the unit's clock.

In this case we end up receiving an additional bogus character
immediately.

The solution in this change is to switch the AUART unit into its reset
state on close() and only release it from its reset state on the next
open().

Note: when the unit is also used as system console it is always 'in use',
so we cannot reset it on close().
Signed-off-by: NJuergen Borleis <jbe@pengutronix.de>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This function clears the reset the AUART unit is in after system start
to make it work.
Signed-off-by: NJuergen Borleis <jbe@pengutronix.de>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix RS232/485 mode incorrect setting after S3/S4 resume for F81504/508/512

We had add RS232/485 RTS control with fecf27a3. But when it
resume from S3/S4, the mode register 0x40 + 0x08 * idx + 7 will
rewrite to 0x01 (RS232 mode).

This patch will modify 2 sections.

One is pci_fintek_init(), if it called when first init, it will
write mode register with 0x01. If it called from S3/S4 resume,
it's will get the relative port data and pass it to
pci_fintek_rs485_config() with NULL rs485 parameter.

The another modification is in pci_fintek_rs485_config(). It'll
re-apply old configuration when the parameter rs485 is NULL.
Signed-off-by: NPeter Hung <hpeter+linux_kernel@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

devtype structures are all declared as const.
Compiler does not complain because we cast
their pointers to save them in .driver_data.
Signed-off-by: NJakub Kicinski <kubakici@wp.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We currently register the uart driver during device probe
which makes it hard to support more than one chip.
Move the driver registration to module init/exit time and
preallocate space for up to 8 lines (4-8 chips).
Reported-by: NMichael Allwright <michael.allwright@upb.de>
Signed-off-by: NJakub Kicinski <kubakici@wp.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In preparation of supporting multiple devices we should save
the per-chip line number (0 or 1), because the uart_port line
will reflect system-wide uart number and will be offseted for
chips other than the first to register.
Signed-off-by: NJakub Kicinski <kubakici@wp.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Support ZTE uart with some registers differing offset.
Probe as platform device for not AMBA IP ID is
available on ZTE uart.
Signed-off-by: NJun Nie <jun.nie@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Improve LCRH register access decision as ARM PL011 lcrh
register serve as both TX and RX, while other SOC may
implement TX and RX function with separated register.
Signed-off-by: NJun Nie <jun.nie@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce register look up table as different SOC venders
may have different register offset for the some register.
Signed-off-by: NJun Nie <jun.nie@linaro.org>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Introduce register accessor to ease loop up table access
in later patch.
Signed-off-by: NJun Nie <jun.nie@linaro.org>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename regs with enumeration to generalize register names.
Signed-off-by: NJun Nie <jun.nie@linaro.org>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NJun Nie <jun.nie@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Pericom PI7C9X795[1248] are Uno/Dual/Quad/Octal UART devices, this
patch enables them, also defines PCI_VENDOR_ID_PERICOM here.
Signed-off-by: NAdam Lee <adam.lee@canonical.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

So far DMA mode were activated when only number of bytes to send was
equal or greater than min_dma_size. Due to requirement that DMA transaction
buffer should be aligned to cache line size, the excessive bytes were
written to FIFO before starting DMA transaction. The problem occurred
when FIFO size were smaller than cache alignment, because writing all
excessive bytes to FIFO would fail. It happened in DMA mode when PIO
interrupts disabled, which caused driver hung.

The solution is to test if buffer is alligned to cache line size before
activating DMA mode, and if it's not, running PIO mode to align buffer
and then starting DMA transaction. In PIO mode, when interrupts are
enabled, lack of space in FIFO isn't the problem, so buffer aligning
will always finish with success.

Cc: <stable@vger.kernel.org> # v3.18+
Reported-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NRobert Baldyga <r.baldyga@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Due to some of serial ports can have FIFO size smaller than cache line
size, and because of need to align DMA buffer address to cache line size,
it's necessary to calculate minimum number of bytes for which we want
to start DMA transaction to be at least cache line size. The simplest
way to meet this requirement is to get maximum of cache line size and
FIFO size.

Cc: <stable@vger.kernel.org> # v3.18+
Reported-by: NKrzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NRobert Baldyga <r.baldyga@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

serial core does not use tty_port_open() or tty_port_close(); serial
core defines and extends it's own tty open() and close() methods
(uart_open() and uart_close(), respectively).

Remove the tty_port activate() and shutdown() initializations, and
the uart_port_activate() function, which is never called.

NB: uart_port_shutdown() is used by uart_close() => uart_shutdown()
call chain (but not via the tty_port methods).
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

uart_close() runs in non-atomic context only; use
spin_lock/unlock_irq instead of saving the interrupt state (which
== on).
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch fixes I/O accesses on the Receiver Holding Register and on the
Transmitter Holding Register. Indeed AVR32 can only perform 32bit I/O
accesses on registers: using 8bit I/O accesses would read or write garbage
data.

Fixes: commit b5199d46 ("tty/serial: at91: add support to FIFOs")
Signed-off-by: NCyrille Pitchen <cyrille.pitchen@atmel.com>
Tested-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The GPIO subsystem provides dummy GPIO consumer functions if GPIOLIB is
not enabled. Hence drivers that depend on GPIOLIB, but use GPIO consumer
functionality only, can still be compiled if GPIOLIB is not enabled.

Relax the dependency on GPIOLIB if COMPILE_TEST is enabled, where
appropriate.
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

According to DesignWare 8250 spec, if auto flow control
mode is enabled, a change in CTS does not cause an interrupt,
so sw-assisted CTS flow control mode will not work properly.

There reported an GPS firmware download failure issue, and we
verified the root cause is, the default sw-assisted CTS flow
control mode can not work properly since no interrupt when got
CTS signal.

This patch is to enable auto CTS mode by defaut if CRTSCTS
is enable for DesignWare 8250 controller.
Signed-off-by: NHuiquan Zhong <huiquan.zhong@intel.com>
Signed-off-by: NQipeng Zha <qipeng.zha@intel.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Documenation/serial/driver requests that the tx_empty callback should
return 0 if there are still chars in the fifo or shifter or TIOCSER_TEMT
(0x01) if no character is pending to be sent.

Fix the mpc52xx serial driver to not return MPC52xx_PSC_SR_TXEMP (i.e.
0x0800) but TIOCSER_TEMT as documented.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In order to use the mctrl_gpio helpers, we change the DT bindings:
ri-gpios renamed to rng-gpios. cd-gpios renamed to dcd-gpios.
However, no in-tree dts/dtsi specifies these, so no worries.
Signed-off-by: NNiklas Cassel <nks@flawful.org>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Implementing enable_ms is optional by serial_core.
check_modem_status is just an empty local function.
Signed-off-by: NNiklas Cassel <nks@flawful.org>
Reviewed-by: NGuenter Roeck <linux@roeck-us.net>
Tested-by: NGuenter Roeck <linux@roeck-us.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When system goes into low power states like SUSPEND_MEM and
HIBERNATION, the hardware IP block may be powered off to reduce
the power consumption. This power down may cause problems on
some imx platforms, because the hardware settings are reset to
its power on default values which may differ from the ones when
it power off. This patch added the dev_pm_ops and implemented
two callbacks: suspend_noirq and resume_noirq, which will save
the necessory hardware parameters right before power down and
recover them before system uses the hardware.

Because added the dev_pm_ops, the old suspend/resume callbacks
under platform_driver will not be called any more. Changed their
prototypes and moved those two callbacks into dev_pm_ops too.
Signed-off-by: NShenwei Wang <shenwei.wang@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If serial8250_register_8250_port() fails, disable and unprepare the
clock before exiting.

Fixes: 1a8d2903 ("serial: 8250_uniphier: add UniPhier serial driver")
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NMatthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add RS485 control for Fintek F81504/508/512

F81504/508/512 can control their RTS with H/W mode.
PCI configuration space for each port is 0x40 + idx * 8 + 7.

When it set with 0x01, it's configured with RS232 mode.
RTS is controlled by MCR.

When it set with 0x11, it's configured with RS485 mode.
RTS is controlled by H/W, RTS low with idle & RX, high with TX.

When it set with 0x31, it's configured with RS485 mode.
RTS is controlled by H/W, RTS high with idle & RX, low with TX.

We will force 0x01 on pci_fintek_setup().
Signed-off-by: NPeter Hung <hpeter+linux_kernel@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit e95044ba.

Commit e95044ba ("tty: serial: imx.c: Reset UART before activating
interrupts") terribly messes up with the console on mx6 boards, so
let's revert it.
Reported-by: Nkernelci.org bot <bot@kernelci.org>
Cc: David Jander <david@protonic.nl>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The Kconfig for this driver is currently:

config SERIAL_SUNHV
        bool "Sun4v Hypervisor Console support"

...meaning that it currently is not being built as a module by
anyone.  Lets remove the modular and unused code here, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

We don't swap module.h for init.h since this file has init.h already.

We leave some tags like MODULE_LICENSE for documentation purposes, and
for the "git blame" value.  Also note that MODULE_DEVICE_TABLE is a
no-op for non-modular code, so we remove that too.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: sparclinux@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The Kconfig for this driver is currently:

config SERIAL_SUNCORE
        bool

...meaning that it currently is not being built as a module by
anyone.  Lets remove the modular and unused code here, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

We don't swap module.h for init.h since this file has init.h already.

We leave some tags like MODULE_LICENSE for documentation purposes, and
for the "git blame" value.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: sparclinux@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>