This patch adds Software flow control support in DMA mode.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg 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: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg 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: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg 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: Robin Gong <b38343@freescale.com>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Greg 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: Anton Bondarenko <anton_bondarenko@mentor.com>
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg 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: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently in dma_tx_callback(), no matter if there is still
remaining data pending in circle buffer or not, DMA transmit
will be terminated.

This will result in some data never get transmitted.
In order to fix this issue, call imx_dma_tx() again in
dma_tx_callback, when there is pending data and uart hasn't
been stopped.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 2ad28e3e.

Instead of always wake up write_wait process in TX callback,
TX callback should call imx_dma_tx() again, and let imx_dma_tx
transfer the remaining data in circle buffer.

The issue with commit 2ad28e3e is, in case there is remaining
data in circle buffer, but no process is waiting on write_wait
queue, then as no following uart_write() will be called after
uart_write_wakeup(), thus cause data loss.

Moreover according to Documentation/serial/driver, uart_write_wakeup()
should be called in case the transmit buffer have dropped below
a threshold.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

To synchronize between dma_tx_callback() and imx_dma_tx() use the same
variable, dma_is_txing. This prevents any race between these two functions
and ensures that a new DMA can start only after the first has been
finished.

Before the new DMA can be set up, update the circular buffer logic, first.
Therefore, change dma_is_txing after that update, instead of before.

While doing this, in dma_tx_callback() extend the locking to dma_unmap_sg()
and the update of dma_is_txing.
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

First, reformat the code to exit immediately. This allows us to add
more code in more readable format.

In case the TX DMA was still running, remove and disable it's resources.
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In case dmaengine_prep_slave_sg() fails, add the missing dma_unmap_sg().
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Inverting the logic of the if statement for the sg initialization
makes the if statement easier and better to read.

No functional change.
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use imx_start_tx() just to enable the TX interrupt. It's the job of the
TX interrupt ISR to fill the transmit buffer, then. If the transmit buffer
is empty, the TX interrupt should be executed as soon as the start_tx()
enables the interrupt, so there is no reason for the extra
imx_transmit_buffer() call, here. Remove it.
Signed-off-by: Dirk Behme <dirk.behme@de.bosch.com>
Signed-off-by: Andy Lowe <andy_lowe@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Several places are accessing the UCR1 register without locking.
This probably will cause a race issue when another thread
is accessing the same register.
Add locking to preventing concurrent access of the UCR1 register.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add CREAD flag hanlding in set_termios and UART DMA mode
which ignores all received chars when CREAD flag cleared.
Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Anton Bondarenko <anton_bondarenko@mentor.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch fixes many bugs in the code dealing with the hardware handshake.

As an example, in atmel_set_termios(), we used to test whether the CRTSCTS
c_cflag was set. If so, we selected the "Hardware Handshake" mode through the
Mode Register. However, few lines below the mode was reset to "Normal" (0).
So there was no way to select the "Hardware Handshake" mode. To fix this issue,
we moved the CRTSCRTS c_cflag test AFTER the mode has been reset to "Normal".

Also setting the RTSEN and RTSDIS bits in the Control Register has different
results whether the USART is set in "Normal" or "Hardware Handshake" mode:

1) "Normal" mode
- the RTSEN bit forces the RTS line to low level, which tells the remote peer
  that we are ready to received new data.
- the RTSDIS bit forces the RTS line to high level, which tells the remote peer
  to stop sending new data.

2) "Hardware Handshake" mode
- the RTSEN bit forces the RTS line to high level.
- the RTSDIS bit lets the hardware control the RTS line.

WARNING:
when FIFOs are not available or not enabled, the RTS line is controlled by the
PDC. This is why using the Hardware Handshake mode requires using the PDC
channel for reception. However the Hardware Handshake mode DOES NOT work with
DMA controller since it cannot control the RTS line.
Future designs with FIFOs will introduce a new feature: the RTS line will be
controlled by the RX FIFO using thresholds. This patch was tested with this new
design.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

-EDEFER error wasn't handle properly by atmel_serial_probe().
As an example, when atmel_serial_probe() is called for the first time, we pass
the test_and_set_bit() test to check whether the port has already been
initalized. Then we call atmel_init_port(), which may return -EDEFER, possibly
returned before by clk_get(). Consequently atmel_serial_probe() used to return
this error code WITHOUT clearing the port bit in the "atmel_ports_in_use" mask.
When atmel_serial_probe() was called for the second time, it used to fail on
the test_and_set_bit() function then returning -EBUSY.

When atmel_serial_probe() fails, this patch make it clear the port bit in the
"atmel_ports_in_use" mask, if needed, before returning the error code.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: <stable@vger.kernel.org> # 3.12+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

atmel_serial_probe() calls atmel_init_port(). In turn, atmel_init_port() calls
clk_disable_unprepare() to disable the peripheral clock before returning.

Later atmel_serial_probe() accesses some I/O registers such as the Mode and
Control registers for RS485 support then the Name and Version registers, through a call to
atmel_get_ip_name(), but at that moment the peripheral clock was still
disabled.
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: <stable@vger.kernel.org> # 3.12+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

dma_sync_*_for_cpu() and dma_sync_*_for_device() use 'enum dma_data_direction',
not 'enum dma_transfer_direction'
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MARCO will not be supported any more and the project was dropped.
it has been replaced by CSR atlas7.
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 2aff5e2b ('tty: Change
tty lock order to master->slave') added a warning which is broken
and unnecessary now that the tty lock has fixed lock subclasses,
added in commit 2febdb63
('tty: Preset lock subclass for nested tty locks').
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This platform_driver does not need to set an owner, it will be populated by the
driver core.
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Enable APM X-Gene SoC serial port functionality when using ACPI table to
initialize serial port.
Signed-off-by: Feng Kan <fkan@apm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to terminate transfer in the __dma_rx_complete() since it's
called at the end of transfer. Special case when serial timeout occurs is
handled separately where we have to terminate transfer.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

By using devm_request_irq() we can have a shorter and cleaner code.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

By using devm_clk_get() we can have a shorter and cleaner code.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

By using devm_kzalloc() we can have a shorter and cleaner code.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of jumping to the 'out' label, let's return the error immediately, which
makes the code shorter and cleaner.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Because the OMAP3 UART ignores MCR[1] (RTS) in autoRTS mode, autoRTS
mode must not be enabled unless RTS is set (or port->mctrl & TIOCM_RTS,
which is equivalent).

Fixes premature raising of RTS in omap_8250_set_termios() -- RTS was
raised even before UART mode was selected.
Fixes raise of RTS after port has been shutdown; omap_8250_pm() re-enabled
RTS after omap_8250_shutdown().

Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The OMAP3 UART ignores MCR[1] (ie., UART_MCR_RTS) when in autoRTS
mode (UPF_HARD_FLOW + CRTSCTS). This makes it impossible for either
the serial core or userspace to manually flow control the sender.

Disable autoRTS mode when RTS is lowered and restore the previous
mode when RTS is raised.

Note that the OMAP3 UART provides no mechanism for switching from
autoRTS mode without corrupting incoming data; to access the
necessary register, the line control settings must be set to 8-e-2
and thus any data received during that time will be interpreted with
those settings. This corruption has been observed in practice.

Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Trivial fixes for omap-serial.
Signed-off-by: Pavel Machek <pavel@ucw.cz>

index 18c30ca..f43ed2c 100644
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

This patch invokes add_preferred_console() with ttyS based on ttyO
arguments if the user didn't specify it on its own. This ensures that
the user will see the kernel booting on his serial console in case he
forgot to update the command line.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The current output of the device probing looks like this:

ColdFire internal UART serial driver
(NULL device *): ttyS0 at MMIO 0xfc060000 (irq = 90, base_baud = 5208333) is a ColdFire UART
console [ttyS0] enabled
(NULL device *): ttyS1 at MMIO 0xfc064000 (irq = 91, base_baud = 5208333) is a ColdFire UART
(NULL device *): ttyS2 at MMIO 0xfc068000 (irq = 92, base_baud = 5208333) is a ColdFire UART

Fix the port device linkage at probing time so that the device name is
printed out properly, and not "(NULL device *)".
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Trivially fix the following compile time warnings:

  CC      drivers/tty/serial/mcf.o
drivers/tty/serial/mcf.c: In function ‘mcf_set_termios’:
drivers/tty/serial/mcf.c:201:19: warning: unused variable ‘pp’
drivers/tty/serial/mcf.c: In function ‘mcf_config_rs485’:
drivers/tty/serial/mcf.c:444:19: warning: unused variable ‘pp’
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Change my email contact address from the obsolete gerg@snapgear.com to
gerg@uclinux.org.
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Pull KVM fixes from Paolo Bonzini:
 "The important fixes are for two bugs introduced by the merge window.

  On top of this, add a couple of WARN_ONs and stop spamming dmesg on
  pretty much every boot of a virtual machine"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  kvm: warn on more invariant breakage
  kvm: fix sorting of memslots with base_gfn == 0
  kvm: x86: drop severity of "generation wraparound" message
  kvm: x86: vmx: reorder some msr writing

Pull vfs fix from Al Viro:
 "An embarrassing bug in lustre patches from this cycle ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  [regression] braino in "lustre: use is_root_inode()"

Modifying a non-existent slot is not allowed.  Also check that the
first loop doesn't move a deleted slot beyond the used part of
the mslots array.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>