Enable reporting of DSR events (which is named DTR in the registers
because Freescale uses the names as seem from a DCE).
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

According to tty_ioctl(4) (from man-pages 4.04) the rng member only
counts 0->1 transitions. For the other signals (DSR, CD, CTS) both edges
are supposed to be counted.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Make sure that events that are not handled in the irq function don't
trigger an interrupt.

When the serial port is operated in DTE mode, the events for DCD and RI
events are enabled after a system reset by default.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This gives the irq core a chance to disable the serial interrupt in case
an event isn't cleared in the handler.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When in DTE mode, the bit USR2_RIIN is active low. So invert the logic
accordingly.

Fixes: 90ebc483 ("serial: imx: repair and complete handshaking")
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Some RS-232 to RS-485 transceivers require Rx to be disabled on Tx to
avoid echo of Tx data into the Rx buffer. Specifically, the XR3160E
RS-232/RS-485/RS-422 transceiver behaves this way.

This commit disables Rx on active Tx when SER_RS485_ENABLED is active and
SER_RS485_RX_DURING_TX is disabled.

Note that this is a change in behavior of the driver. Until now
SER_RS485_RX_DURING_TX was enabled unconditionally even when disabled in
the TIOCSRS485 ioctl serial_rs485 flags field.

Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NBaruch Siach <baruch@tkos.co.il>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When a non console i.MX UART is enabled in the device tree,
system suspend fails due to an unprepared clock:

[  638.794563] PM: Syncing filesystems ... done.
[  638.878902] Freezing user space processes ... (elapsed 0.002 seconds) done.
[  638.888454] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done.
[  638.996697] PM: suspend of devices complete after 97.200 msecs
[  639.002611] PM: suspend devices took 0.100 seconds
[  639.013020] PM: late suspend of devices complete after 2.288 msecs
[  639.021486] ------------[ cut here ]------------
[  639.026147] WARNING: CPU: 0 PID: 488 at drivers/clk/clk.c:732 clk_core_enable+0xc0/0x12c()
[  639.034413] Modules linked in:
[  639.037490] CPU: 0 PID: 488 Comm: system_server Tainted: G        W       4.4.0-rc5-pknbsp-svn2214-atag-v4.4-rc5-121-gebfd9cb #1304
[  639.049312] Hardware name: Freescale i.MX53 (Device Tree Support)
[  639.055444] [<c0016d54>] (unwind_backtrace) from [<c00140f8>] (show_stack+0x20/0x24)
[  639.063199] [<c00140f8>] (show_stack) from [<c02c99a0>] (dump_stack+0x20/0x28)
[  639.070442] [<c02c99a0>] (dump_stack) from [<c0024ca8>] (warn_slowpath_common+0x88/0xc0)
[  639.078541] [<c0024ca8>] (warn_slowpath_common) from [<c0024d0c>] (warn_slowpath_null+0x2c/0x34)
[  639.087332] [<c0024d0c>] (warn_slowpath_null) from [<c05171e8>] (clk_core_enable+0xc0/0x12c)
[  639.095777] [<c05171e8>] (clk_core_enable) from [<c05172f8>] (clk_enable+0x2c/0x40)
[  639.103441] [<c05172f8>] (clk_enable) from [<c0349880>] (imx_serial_port_suspend_noirq+0x20/0xe0)
[  639.112336] [<c0349880>] (imx_serial_port_suspend_noirq) from [<c03a26a0>] (dpm_run_callback+0x68/0x16c)
[  639.121825] [<c03a26a0>] (dpm_run_callback) from [<c03a2898>] (__device_suspend_noirq+0xf4/0x22c)
[  639.130705] [<c03a2898>] (__device_suspend_noirq) from [<c03a4b0c>] (dpm_suspend_noirq+0x148/0x30c)
[  639.139764] [<c03a4b0c>] (dpm_suspend_noirq) from [<c00511d4>] (suspend_devices_and_enter+0x2e8/0x6a4)
[  639.149078] [<c00511d4>] (suspend_devices_and_enter) from [<c00518a0>] (pm_suspend+0x310/0x4b8)
[  639.157782] [<c00518a0>] (pm_suspend) from [<c00500ec>] (state_store+0x7c/0xcc)
[  639.165099] [<c00500ec>] (state_store) from [<c02cb6dc>] (kobj_attr_store+0x1c/0x28)
[  639.172858] [<c02cb6dc>] (kobj_attr_store) from [<c01633d4>] (sysfs_kf_write+0x54/0x58)
[  639.180871] [<c01633d4>] (sysfs_kf_write) from [<c01629b4>] (kernfs_fop_write+0x100/0x1c8)
[  639.189152] [<c01629b4>] (kernfs_fop_write) from [<c00fb8b8>] (__vfs_write+0x3c/0xe8)
[  639.196991] [<c00fb8b8>] (__vfs_write) from [<c00fc810>] (vfs_write+0xa4/0x160)
[  639.204307] [<c00fc810>] (vfs_write) from [<c00fcac4>] (SyS_write+0x4c/0x98)
[  639.211363] [<c00fcac4>] (SyS_write) from [<c0010760>] (ret_fast_syscall+0x0/0x3c)

This does not happen for the common case of a single UART used as a console
(since imx_console_setup() already does a prepare)
Signed-off-by: NMartin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Now that imx_mctrl_check is implemented below imx_get_mctrl the former
can call the latter directly instead of via sport->port.ops->get_mctrl.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The .get_mctrl callback should not report the status of RTS or LOOP, so
drop this. Instead implement reporting the state of CAR (aka DCD) and
RI.

For .set_mctrl implement setting the DTR line.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

of_match_device could return NULL, and so cause a NULL pointer
dereference later.
Even if the probability of this case is very low, fixing it made
static analyzers happy.
Solving this with of_device_get_match_data made also code simplier.
Signed-off-by: NLABBE Corentin <clabbe.montjoie@gmail.com>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 9e7b399d.

Commit ("9e7b399d") causes the following warning and sometimes
also hangs the system:

------------[ cut here ]------------
 WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:868 mutex_trylock+0x20c/0x22c()
 DEBUG_LOCKS_WARN_ON(in_interrupt())
 Modules linked in:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.2.0-rc7-next-20150818-00001-g14418a6 #4
Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
Backtrace:
[<80012f08>] (dump_backtrace) from [<800130a4>] (show_stack+0x18/0x1c)
r6:00000364 r5:00000000 r4:00000000 r3:00000000
[<8001308c>] (show_stack) from [<807902b8>] (dump_stack+0x88/0xa4)
[<80790230>] (dump_stack) from [<8002a604>] (warn_slowpath_common+0x80/0xbc)
r5:807945c4 r4:80ab3b50
[<8002a584>] (warn_slowpath_common) from [<8002a6e4>] (warn_slowpath_fmt+0x38/0x40)
r8:00000000 r7:8131100c r6:8054c3cc r5:8131300c r4:80b0a570
[<8002a6b0>] (warn_slowpath_fmt) from [<807945c4>] (mutex_trylock+0x20c/0x22c)
r3:8095d0d8 r2:8095ab28
[<807943b8>] (mutex_trylock) from [<8054c3cc>] (clk_prepare_lock+0x14/0xf4)
r7:8131100c r6:be3f0c80 r5:00000037 r4:be3f0c80
[<8054c3b8>] (clk_prepare_lock) from [<8054dbfc>] (clk_prepare+0x18/0x30)
r5:00000037 r4:be3f0c80
[<8054dbe4>] (clk_prepare) from [<8036a600>] (imx_console_write+0x30/0x244)
r4:812d0bc8 r3:8132b9a4

To reproduce the problem we only need to let the board idle for something
like 30 seconds.

Tested on a imx6q-sabresd.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: NEduardo Valentin <edubezval@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The RX bytecount was only updated in the PIO path and thus
the device erroneously reported a value of 0 if DMA is in
use.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The commit enabling DMA support even if no flow control is present
was reverted on the grounds that it uncovered a number of bugs in
the code that lead to hanging tty devices and/or missing characters.

After tracking down the issues it is clear that those were generic
bugs and had nothing to do with flow control being present or not,
only that allowing DMA without hardware flow control increased
the exposure of that code a lot.

Now that those bugs are fixed, it should be safe to re-enable DMA
support.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The reference manual states that idle condition detect should not be used
with DMA transfers, as the ROM SDMA scripts don't check those conditions.

The RAM SDMA scripts worked around this, but the change broke compatibility
with the ROM scripts.

The previous commits fixed the DMA burst sizes, so that the aging timer is
now working as described in the reference manual. With this fixed we can
remove the hack of using the idle condition detect to stop the DMA transfer
if there are no new characters incoming.

This should work with both the ROM and RAM SDMA scripts.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Triggering the DMA engine for every byte is horribly inefficient.
Also it doesn't allow to use the aging timer for the RX FIFO as this
requires the DMA engine to leave one byte remaining in the FIFO when
doing a normal burst transfer.

Adjust watermark levels so that the DMA engine can do at least 8 byte
burst transfers. This is a conservative value, as the both TX and RX
FIFOs are able to contain 32 bytes.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Simplify the DMA restart logic to always queue up the next transfer
immediately if there is at least one more byte available in the FIFO,
so that the transfer will finish in a limited time.

This way the driver stops to rely on zero length transfers to signal
transfers ends. Those will go away when the idle detect DMA requests
are disabled.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The DMA transfer is only started once we are sure it will finish
in a limited time, i.e. only after we received a RRDY interrupt.

In order to allow the watermark level to be raised the aging
timer and the corresponding interrupt need to be set up as an
additional trigger, so that the transfer is also started if the
incoming amount of bytes never reach the watermark.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This function currently doesn't use its parameter.

Change prototype to pass in watermark levels, so we can reuse this
function in the DMA setup paths. Also relocate to be near the calling
functions.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Acked-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Earlycon allows to have an early debugging console that doesn't need
to be statically configured in the kernel config, like earlyprintk,
but is set up through the stdout-path DT property.

This allows to have the early debugging always built into the
kernel and enabled on demand without clashing between different boards
or architectures.
Signed-off-by: NLucas Stach <l.stach@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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>

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>

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>

This reverts commit 068500e0.

According to some tests, SDMA support is broken at least for i.MX6 without
HW flow control. Different forms of data-corruption appear either with
the ROM firmware for the SDMA controller as well as when loading Freescale
provided SDMA firmware versions 1.1 or 3.1.
Signed-off-by: NDavid Jander <david@protonic.nl>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If the UART has been in use before this driver was loaded, IRQs might be
active and get fired as soon as we set the handler, which will crash
in the spin_lock_irqsave(&sport->port.lock, flags) because port.lock is
not initialized until the port is added at the end of probe.
Signed-off-by: NDavid Jander <david@protonic.nl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

To prevent problems with interrupt latency, and due to the fact, that
the error will be counted anyway (icount.overrun), the dev_err is simply
removed.

Background:
If an rx-fifo overflow occurs a dev_err message was called in interrupt
context. Since dev_err messages are written to console in a synchronous way
(unbuffered), and console may be a serial terminal, this leads to a
highly increased interrupt-latency (several milliseconds).
As a result of the high latency more rx-fifo overflows will happen, and
therefore a feedback loop of errors is created.
Signed-off-by: NManfred Schlaegl <manfred.schlaegl@gmx.at>
Acked-By: NAlexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

As can be seen in function uart_insert_char (serial_core) the element
buf_overrun of struct uart_icount is used to count overruns of
tty-buffer.
Added support for counting of overruns in imx driver analogue to
serial_core.
Signed-off-by: NManfred Schlaegl <manfred.schlaegl@gmx.at>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Disable interrupts before requesting them in order to fix a kernel oops
after lauching a kernel via kexec.

Tested on a imx6sl-evk board.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The driver configures the IDLE condition to interrupt the SDMA engine.
Since the SDMA UART ROM script doesn't clear the IDLE bit itself, this
caused repeated 1-byte DMA transfers, regardless of available data in the
RX FIFO. Also, when returning due to the IDLE condition, the UART ROM
script already increased its counter, causing residue to be off by one.

This patch clears the IDLE condition to avoid repeated 1-byte DMA transfers
and decreases count by when the DMA transfer was aborted due to the IDLE
condition, fixing serial transfers using DMA on i.MX6Q.
Reported-by: NPeter Seiderer <ps.report@gmx.net>
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Tested-by: NFabio Estevam <fabio.estevam@freescale.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The platform_device_id is not modified by the driver and core uses it as
const.
Signed-off-by: NKrzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The return value from imx_setup_ufcr() is always 0 and its value is never
checked, so better to remove the return value.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Previously Soft Reset (clear of SRST bit in UCR2 register)
of UART in startup is not protected by lock, which may have race
with console_write, as console_write may occur at anytime even
when UART port is shutdown.

To avoid this race, protect Soft reset of UART port with spin_lock.
Signed-off-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 17b8f2a3 ("serial: imx: add support for half duplex rs485")
introduced the following build warning:

drivers/tty/serial/imx.c: In function 'imx_set_termios':
drivers/tty/serial/imx.c:1301:7: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]

Add the suggested braces to avoid the build warning.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The transmitter is expected to be controlled by the UART's RTS pin.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Support for IRDA was added in 2009 in commit v2.6.31-rc1~399^2~2. There
are no in-tree users.
Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>