There is no need to explicitly zero the 'ret' variable as it is properly
initialized in a few lines below as:

ret = serial_mxs_probe_dt(s, pdev);

Remove the unneeded zeroing of 'ret'.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We should check whether platform_get_irq() failed, and in the case of error
this needs to be propagated.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The irq number is only used inside the probe function, so there is no need
to keep it in the private mxs_auart_port structure.

Use a local 'irq' variable for storing the irq number instead.

Also make its type of 'int' as platform_get_irq() may fail and return a
negative number.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The Digicolor USART hardware does not support detecting the BREAK condition.
This means that we can't support sysrq on this hardware. Remove all reference
to sysrq from the code.

This also fixes build when sysrq is disabled:

drivers/tty/serial/digicolor-usart.c: In function 'digicolor_uart_console_write':
drivers/tty/serial/digicolor-usart.c:407:33: error: 'struct uart_port' has no member named 'sysrq'
Reported-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NBaruch Siach <baruch@tkos.co.il>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the kernel command line parameter, no_console_suspend, is used,
the console should continue to output console messages during and
after system suspend. For a serial console, the serial core ensures
that the device is not shutdown when no_console_suspend is specified.
However, the default operation of the pnp bus will disable and suspend
the device and no further output occurs.

When registering the 8250 port, if the serial device is a console
set the PNP_CONSOLE capability, which prevents device power-off
if consoles are not suspending.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

unregister_console() will be called from uart_remove_one_port() while
removing the platform driver. So not necessary to call it in driver
exit path.
Signed-off-by: NPramod Gurav <pramod.gurav@smartplayin.com>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The change does following:
 - baud, flow, bits, parity were being overwritten as they were
   being reinitialized after parsing.  Initialize them when they are
   declared so that user provided setting are not overwritten.
 - msm_set_baud_rate() is anyway called in uart_set_options when it calls
   msm_set_termios(). msm_reset() is called when we change the baud rate.
   Hence doing away with both of these calls.
 - CR_CMD_PROTECTION_EN and CR_TX_ENABLE settings are done in msm_set_baud_rate.
   So do away with this here.
Signed-off-by: NPramod Gurav <pramod.gurav@smartplayin.com>
Reviewed-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Intel Moorestown platform support was removed few years ago. This is a follow
up which removes Moorestown specific code for the serial devices. It includes
mrst_max3110 and earlyprintk bits.

This was used on SFI (Medfield, Clovertrail) based platforms as well, though
new ones use normal serial interface for the console service.
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: NDavid Cohen <david.a.cohen@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When running an userspace program that does a 'tcflush(fd, TCIOFLUSH)' call
we still see the last received character in the URXD register afterwards.

Clear UCR2_SRST bit so that the UART FIFO is flushed properly.

Since UCR2_SRST also resets some UART registers, we need to save and restore
some of them.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Tested-by: NFugang Duan <B38611@freescale.com>
Acked-by: NJason Liu <r64343@freecale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

On uart buffer flush, serial core resets the circular buffer.
If a DMA transfer is in progress at that time, the callback
lpuart_dma_tx_complete will move buffer's tail unconditionally,
hence tail moves beyond head. Use the flush_buffer hook to
terminate the DMA imeaditely and avoid lpuart_dma_tx_complete
being called in this situation.

This bug often showed up while shutdown and lead to duplicate
serial console output.
Signed-off-by: NStefan Agner <stefan@agner.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

For power management support, we should disable TX and
TX interrupt so that kernel can prepare for deep sleep.

Retain RX and RX interrupt for wakeup the kernel when
receive the input character.
Signed-off-by: NYuan Yao <yao.yuan@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

To end a DMA transfer which did not consume a whole buffer (e.g. one
character only), a RX timer is used. When lots of data are received
the DMA transfer will complete and setup another DMA transfer, which
in turn might complete again. In this cases, it is not necessary to
abort the DMA transfers using the RX timer. This change pushes the
RX timer timeout into the future each time a DMA transfer completed.

Aborting the DMA was not very harmful, since the next received
character lead to setup of another RX DMA.
Signed-off-by: NStefan Agner <stefan@agner.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move the DMA channel request to probe to avoid requesting the DMA
channel on each opening of the ttyLPx device. This also fixes a
potential issue that TX channel is not freed when only RX channel
allocation fails. The DMA channels are now handled independently,
so one could use UART with DMA only in TX direction for instance.
Signed-off-by: NStefan Agner <stefan@agner.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When the UART is in DMA receive mode (RDMAS set) and one character
just arrived while another interrupt is handled (e.g. TX), the RDRF
(receiver data register full flag) is set due to the water level of
1. But since the DMA will take care of this character, there is no
need to handle it by calling lpuart_prepare_rx. Handling it leads to
adding the RX timeout timer twice:

[   74.336698] Kernel BUG at 80053070 [verbose debug info unavailable]
[   74.342999] Internal error: Oops - BUG: 0 [#1] ARM0:00.00 khungtaskd
[   74.347817] Modules linked in:    0 S  0.0  0.0   0:00.00 writeback
[   74.350926] CPU: 0 PID: 0 Comm: swapper Not tainted 3.19.0-rc3-00001-g39d78e2 #1788
[   74.358617] Hardware name: Freescale Vybrid VF610 (Device Tree)t
[   74.364563] task: 807a7678 ti: 8079c000 task.ti: 8079c000 kblockd
[   74.370002] PC is at add_timer+0x24/0x28.0  0.0   0:00.09 kworker/u2:1
[   74.373960] LR is at lpuart_int+0x15c/0x3d8
[   74.378171] pc : [<80053070>]    lr : [<802e0d88>]    psr: a0010193
[   74.378171] sp : 8079de10  ip : 8079de20  fp : 8079de1c
[   74.389694] r10: 807d44c0  r9 : 8688c300  r8 : 00000013
[   74.394943] r7 : 20010193  r6 : 00000000  r5 : 000000a0  r4 : 86997210
[   74.401498] r3 : ffffa7da  r2 : 80817868  r1 : 86997210  r0 : 86997344
[   74.408052] Flags: NzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
[   74.415489] Control: 10c5387d  Table: 8611c059  DAC: 00000015
[   74.421265] Process swapper (pid: 0, stack limit = 0x8079c230)
...

Solve this by only execute the receiver path (lpuart_prepare_rx) if
the DMA receive mode (RDMAS) is not set. Also, make sure the flag is
cleared on initialization, in case it has been left set.

This can be best reproduced using UART as a serial console, then
running top while dd'ing data into the terminal.
Signed-off-by: NStefan Agner <stefan@agner.ch>
Cc: stable <stable@vger.kernel.org> # 3.14
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If the serial port gets closed while a RX transfer is in progress,
the timer might fire after the serial port shutdown finished. This
leads in a NULL pointer dereference:

[    7.508324] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[    7.516590] pgd = 86348000
[    7.519445] [00000000] *pgd=86179831, *pte=00000000, *ppte=00000000
[    7.526145] Internal error: Oops: 17 [#1] ARM
[    7.530611] Modules linked in:
[    7.533876] CPU: 0 PID: 123 Comm: systemd Not tainted 3.19.0-rc3-00004-g5b11ea7 #1778
[    7.541827] Hardware name: Freescale Vybrid VF610 (Device Tree)
[    7.547862] task: 861c3400 ti: 86ac8000 task.ti: 86ac8000
[    7.553392] PC is at lpuart_timer_func+0x24/0xf8
[    7.558127] LR is at lpuart_timer_func+0x20/0xf8
[    7.562857] pc : [<802df99c>]    lr : [<802df998>]    psr: 600b0113
[    7.562857] sp : 86ac9b90  ip : 86ac9b90  fp : 86ac9bbc
[    7.574467] r10: 80817180  r9 : 80817b98  r8 : 80817998
[    7.579803] r7 : 807acee0  r6 : 86989000  r5 : 00000100  r4 : 86997210
[    7.586444] r3 : 86ac8000  r2 : 86ac9bc0  r1 : 86997210  r0 : 00000000
[    7.593085] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[    7.600341] Control: 10c5387d  Table: 86348059  DAC: 00000015
[    7.606203] Process systemd (pid: 123, stack limit = 0x86ac8230)

Setup the timer on UART startup which allows to delete the timer
unconditionally on shutdown. This also saves the initialization
on each transfer.
Signed-off-by: NStefan Agner <stefan@agner.ch>
Cc: stable <stable@vger.kernel.org> # 3.14
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 26df6d13 ("tty: Add EXTPROC support for LINEMODE")
allows a process which has opened a pty master to send _any_ signal
to the process group of the pty slave. Although potentially
exploitable by a malicious program running a setuid program on
a pty slave, it's unknown if this exploit currently exists.

Limit to signals actually used.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Howard Chu <hyc@symas.com>
Cc: One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: <stable@vger.kernel.org> # 2.6.36+
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The vcs device's poll/fasync support relies on the vt notifier to signal
changes to the screen content.  Notifier invocations were missing for
changes that comes through the selection interface though.  Fix that.

Tested with BRLTTY 5.2.
Signed-off-by: NNicolas Pitre <nico@linaro.org>
Cc: Dave Mielke <dave@mielke.cc>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently vt_bind and vt_unbind access at least the con_driver object
and registered_con_driver array without holding the console lock. Fix
this by locking around the whole function in each case.
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The default console driver (conswitchp) and busy drivers bound to a
console (as reported by con_is_bound()) shouldn't be unregistered.
System console drivers (without the CON_DRIVER_FLAG_MODULE flag) can be
unregistered, provided they are neither default nor busy. The current
code checks for the CON_DRIVER_FLAG_INIT flag but this doesn't make
sense: this flag is set for a driver whenever its associated console's
con_startup() function is called, which first happens when the console
driver is registered (so before the console gets bound) and gets cleared
when the console gets unbound. The purpose of this flag is to show if we
need to call con_startup() on a console before we use it.

Based on the above, do_unregister_con_driver() in its current form will
allow unregistering a console driver only if it was never bound, but
will refuse to unregister one that was bound and later unbound.

Fix this by dropping the CON_DRIVER_FLAG_INIT check, allowing
unregistering of any console driver provided that it's not the default
one and it's not busy.

v2:
- reword the third paragraph to clarify how the fix works (Peter Hurley)
v3:
- unchanged
v4:
- Allow unregistering a system console driver too, needed by i915 to
  unregister vgacon. Update commit description accordingly. (Daniel)
Signed-off-by: NImre Deak <imre.deak@intel.com>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace a misspelled function name by %s and then __func__.

This was done using Coccinelle, including the use of Levenshtein distance,
as proposed by Rasmus Villemoes.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace the last argument of serial_paranoia_check by the actual function
name.

This was done using Coccinelle, including the use of Levenshtein distance,
as proposed by Rasmus Villemoes.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In early 8250, IER is already zero so no point in writing this - twice
per line

This helped improve the SystemC model based ARC OSCI platform

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Rob Herring <robh@kernel.org>
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Some of FSL SoCs like T1040 has new version of UART controller which
can support 64byte FiFo.
To enable 64 byte support, following needs to be done:
-FCR[EN64] needs to be programmed to 1 to enable it.
-Also, when FCR[EN64]==1, RTL bits to be used as below
to define various Receive Trigger Levels:
        -FCR[RTL] = 00  1 byte
        -FCR[RTL] = 01  16 bytes
        -FCR[RTL] = 10  32 bytes
        -FCR[RTL] = 11  56 bytes
-tx_loadsz is set to 63-bytes instead of 64-bytes to implement
 workaround of errata A-008006 which states that tx_loadsz should
 be configured less than Maximum supported fifo bytes
Signed-off-by: NVijay Rai <vijay.rai@freescale.com>
Signed-off-by: NPriyanka Jain <Priyanka.Jain@freescale.com>
Signed-off-by: NPoonam Aggrwal <poonam.aggrwal@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NBaruch Siach <baruch@tkos.co.il>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When IGNPAR is set in termios->c_iflag,  characters with
framing errors should be ignored.
Signed-off-by: NEric Nelson <eric.nelson@boundarydevices.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If IGNPAR/INPCK are clear in termios->c_iflag,  characters
received with parity or framing errors should be preserved
and passed to the upper layers of the tty stack.

Specifically, the decision of whether to set the character
value to zero should be made by n_tty.c/n_tty_receive_parity_error().
Signed-off-by: NEric Nelson <eric.nelson@boundarydevices.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add device pointer to port->dev.

Before:

"(NULL device *): ttyAL0 at MMIO 0x2020 (irq = 6, base_baud = 3125000)
is a Altera UART"

After:
"altera_uart 2020.serial: ttyAL0 at MMIO 0x2020 (irq = 6, base_baud = 3125000)
is a Altera UART"
Signed-off-by: NLey Foon Tan <lftan@altera.com>
Acked-by: NTobias Klauser <tklauser@distanz.ch>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add device pointer to port->dev.

Before:

"(NULL device *): ttyJ0 at MMIO 0x1008 (irq = 2, base_baud = 0) is a
Altera JTAG UART"

After:
"altera_jtaguart 1008.serial: ttyJ0 at MMIO 0x1008 (irq = 2, base_baud = 0) is a
Altera JTAG UART"
Signed-off-by: NLey Foon Tan <lftan@altera.com>
Acked-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add RX DMA transfers support for samsung serial driver. It's enabled
when DMA controller for RX channel is specified in device-tree.

DMA transactions are started when number of bytes in RX FIFO reaches
trigger level, otherwise PIO mode is used. DMA transfer size is always
PAGE_SIZE which can cause large latency when smaller data amount is
transferred, so we always terminate DMA transaction on RX timeout
interrupt. Timeout interval is set to 64 frame times.

Based on previous work of Sylwester Nawrocki and Lukasz Czerwinski.
Signed-off-by: NRobert Baldyga <r.baldyga@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add TX DMA transfers support for samsung serial driver. It's enabled
when "dmas" property is defined in serial device-tree node, otherwise
TX transfers are prerformed using PIO.

TX DMA is used for data segments larger than fifosize to reduce number
of interrupts during data transmission. For buffers shorter than fifosize
PIO mode is selected.

Data blocks for DMA transfers are aligned to cache line size to avoid
problems with coherency (some areas of TX circ buffer can be used by
CPU during DMA transaction, so we have to ensure that our data is always
consistent).

Based on previous work of Sylwester Nawrocki and Lukasz Czerwinski.
Signed-off-by: NRobert Baldyga <r.baldyga@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add functions requesting and releasing RX and TX DMA channels. This
function are called only when "dmas" property in serial device-tree
node is defined.

Based on previous work of Sylwester Nawrocki and Lukasz Czerwinski.
Signed-off-by: NRobert Baldyga <r.baldyga@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When we have "dmas" property in serial node in device-tree, we do
memory alocation for dma structure which will be used in DMA handling
code.

Based on previous work of Sylwester Nawrocki and Lukasz Czerwinski.
Signed-off-by: NRobert Baldyga <r.baldyga@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This struct contains DMA configuration for each serial port.
It will be used in next commits adding DMA support in driver.

Based on previous work of Sylwester Nawrocki and Lukasz Czerwinski.
Signed-off-by: NRobert Baldyga <r.baldyga@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch adds Software flow control support in DMA mode.
Signed-off-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After send out x_char in UART driver, x_char needs to be cleared
by UART driver itself, otherwise data in TXFIFO can no longer be
sent out.
Also tx counter needs to be increased to keep track of correct
number of transmitted data.
Signed-off-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Other than enable Receiver Overrun Interrupt Enable (UCR4_OREN)
in start_tx interface, UCR4_OREN should be enabled before enable
of Receiver.
Signed-off-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Start rx_dma once RXFIFO is not empty that can avoid dma request lost
and causes data delay issue.
Signed-off-by: NRobin Gong <b38343@freescale.com>
Signed-off-by: NFugang Duan <B38611@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

DMA mode for UART can be used even w/o HW flow control with RTS/CTS.
So it need to be initialized and enabled earlier.
Signed-off-by: NAnton Bondarenko <anton_bondarenko@mentor.com>
Signed-off-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Terminating the DMA, make sure the interrupt is disabled, too.
This fixes random kernel Oops due to dma_tx_call() called for
invalid transmissions.

If we disable the TDMAEN, make sure it's enabled again if a TX
DMA is started.
Signed-off-by: NJiada Wang <jiada_wang@mentor.com>
Signed-off-by: NDirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>