Fix incorrect read-modify-write sequence in lpuart_flush_buffer() that
was reading from UARTPFIFO and writing to UARTCFIFO instead of
operating solely on the latter.

Fixes: 9bc19af9 ("tty: serial: fsl_lpuart: Flush HW FIFOs in .flush_buffer")
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Reported-by: NVivien Didelot <vivien.didelot@gmail.com>
Tested-by: NVivien Didelot <vivien.didelot@gmail.com>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFabio Estevam <festevam@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Jiri Slaby <jslaby@suse.com>
Link: https://lore.kernel.org/r/20191004215537.5308-1-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In a mixed DMA/IRQ use-case (e.g.: DMA for TX, IRQ for RX), interrupt
handler might try to handle Rx/Tx condition it shouldn't. Change the
code to only handle TX/RX event if corresponding path isn't being
handled by DMA.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-7-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Enabling TIE in .startup() callback causes the driver to start (or at
least try) to transmit data before .start_tx() is called. Which, while
harmless (since TIE handler will immediately disable it), is a no-op
and shouldn't really happen. Drop UARTCR2_TIE from list of bits set in
lpuart_startup().

This change will also not enable TIE in .resume(), but it seems that,
similart to .startup(), transmit interrupt shouldn't be enabled there
either.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-6-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Most users of lpuart*_setup_watermark() enable identical set of flags
right after the call, so combine those two action into a subroutine
and make use of it.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-5-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Code doing final steps of TX/RX configuration in lpuart32_startup()
and lpuart_resume() is identical, so move it into a standalone
subroutine.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-4-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Code doing initial DMA RX configuration in lpuart_startup() and
lpuart32_startup() is exactly the same, so move it into a standalone
subroutine.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-3-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Code configure DMA TX path in lpuart_startup(), lpuart32_startup() and
lpuart_resume() is doing exactly the same thing, so move it into a
standalone subroutine.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190805185701.22863-2-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

We don't need dev_err() messages when platform_get_irq() fails now that
platform_get_irq() prints an error message itself when something goes
wrong. Let's remove these prints with a simple semantic patch.

// <smpl>
@@
expression ret;
struct platform_device *E;
@@

ret =
(
platform_get_irq(E, ...)
|
platform_get_irq_byname(E, ...)
);

if ( \( ret < 0 \| ret <= 0 \) )
{
(
-if (ret != -EPROBE_DEFER)
-{ ...
-dev_err(...);
-... }
|
...
-dev_err(...);
)
...
}
// </smpl>

While we're here, remove braces on if statements that only have one
statement (manually).

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NStephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/20190730181557.90391-45-swboyd@chromium.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Last steps of .shutdown() code are identical for lpuart and lpuart32
cases, so move it all into a standalone subroutine.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-19-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

By the time lpuart_shutdown() calls lpuart_stop_tx() UARTCR2_TE and
UARTCR2_TIE (which the latter will clear) are already cleared, so that
function call should effectively be a no-op. Moreso, lpuart_stop_tx()
is expected to be executed with port spinlock held, which the caller
doesn't. Given all that, drop the call to lpuart_stop_tx() in
lpuart_shutdown().

In case of lpuart32_shutdown()/lpuart32_stop_tx(), TIE won't even be
set if lpuart_dma_tx_use is true. Drop it there as well.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-18-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The check for

    uart_circ_empty(xmit) || uart_tx_stopped(&sport->port)

appears in multiple places in the driver. Move it into a helper
function.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-17-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use cpu_relax() instead of barrier() in a tight polling loops to make
them a bit more idiomatic. Should also improve things on ARM64 a bit
since cpu_relax() will expand into "yield" instruction there.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-16-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Busy polling on a bit in a register is used in multiple places in the
driver. Move it into a shared function.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-15-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When dealing with 32-bit variant of LPUART IP block appropriate I/O
helpers have to be used to properly deal with endianness
differences. Change all of the offending code to do that.

Fixes: a5fa2660 ("tty/serial/fsl_lpuart: Add CONSOLE_POLL support
for lpuart32.")
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-14-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clearing CSTOPB bit if it is set is functionally equivalent to jsut
clearing it unconditionally. Drop unnecessary check.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-13-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Drop unnecessary extra parenthesis in the driver.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-12-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The check for termios->c_cflag & CRTSCTS ensure that if we reach else
branch, CRTSCTS in termios->c_cflag is already going to be
cleard. Doing so explicitly there is not necessary. Drop it.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-11-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

While sharing code for Tx interrupt handler between 8 and 32 bit
variant of the peripheral saves a bit of code duplication it also adds
quite a number of lpuart_is_32() checks which makes it harder to
understand. Move shared bits back into corresponding
lpuart*_transmit_buffer functions, split lpuart_txint into
lpuart_txint and lpuart32_txint so we can drop all extra
lpuart_is_32() check and make the code flow more linear.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-10-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Although I haven't observed this bug in practice, it seems that the
code for handling x_char of LPUART is pretty much identical to that of
i.MX. So the fix found in commit 7e2fb5aa ("serial: imx: Fix issue
in software flow control"):

    serial: imx: Fix issue in software flow control

    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>

should apply here as well.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-9-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Uart_write_wakeup() will already be called as a part of
lpuart*_transmit_buffer() call, so there doesn't seem to be a reason
to call it again right after.

It also appears that second uart_write_wakeup() might potentially
cause unwanted write wakeup when transmitting an x_char. See commit
5e42e9a3 ("serial: imx: Fix x_char handling and tx flow control")
where this problem was fixed in a very similarly structured i.MX UART
driver.
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-8-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix bogus indentation in rx_dma_timer_init().
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-6-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

It appears that lpuart_rxint, lpuart_txint and lpuart32_rxint were
modelled after identical function found in UART driver for
i.MX. However, while said functions are used as individual IRQ
handlers in i.MX driver (in case of i.MX1), it is not the case for
LPUART. Given that, there's no need for us to restrict the prototype
of the handler to irqreturn_t foo(int, void *) and we can drop all of
uneened boilerplate code by changing it void foo(struct lpuart_port *).
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-5-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Switching baud rate might cause bogus data to appear in HW
FIFO. Add code to do a HW FIFO flush to .flush_buffer callback to
avoid that.
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-4-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

After overruns the FIFO pointers become misaligned. This
typically shows by characters still being stuck in the FIFO
despite the empty flag being asserted. After the first
assertion of the overrun flag the empty flag still seems to
indicate FIFO state correctly and all data can be read.
However, after another overrun assertion the FIFO seems to
be off by one such that the last received character is still
in the FIFO (despite the empty flag being asserted).

Flushing the receive FIFO reinitializes pointers. Hence it
is recommended to flush the FIFO after overruns, see also:
https://community.nxp.com/thread/321175

Hence, on assertion of the overrun flag read the remaining
data from the FIFO and flush buffers.
Signed-off-by: NStefan Agner <stefan.agner@toradex.com>
Acked-by: NMax Krummenacher <max.krummenacher@toradex.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-3-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using DMA framing error get cleared properly. However, due
to the additional read from the data register, an underflow in
the receive FIFO buffer occurs (the FIFO pointer gets out of
sync).

Clear the FIFO in case an underflow has occurred. Also disable the
receiver during this operation and when reading the data register to
minimize potential interference.
Signed-off-by: NStefan Agner <stefan.agner@toradex.com>
Acked-by: NMax Krummenacher <max.krummenacher@toradex.com>
Signed-off-by: NAndrey Smirnov <andrew.smirnov@gmail.com>
Cc: Stefan Agner <stefan@agner.ch>
Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: Cory Tusar <cory.tusar@zii.aero>
Cc: Lucas Stach <l.stach@pengutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-imx@nxp.com
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Link: https://lore.kernel.org/r/20190729195226.8862-2-andrew.smirnov@gmail.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

VF610/LS1021a/i.MX7ULP/i.MX8QXP reference manual describe the
TXFIFOSIZE/RXFIFOSIZE field as below.

000b - FIFO/Buffer depth = 1 dataword.
001b - FIFO/Buffer depth = 4 datawords.
010b - FIFO/Buffer depth = 8 datawords.
011b - FIFO/Buffer depth = 16 datawords.
100b - FIFO/Buffer depth = 32 datawords.
101b - FIFO/Buffer depth = 64 datawords.
110b - FIFO/Buffer depth = 128 datawords.
111b - FIFO/Buffer depth = 256 datawords. (Reserved for VF610)

So the FIFO depth should be: 0x1 << (val ? (val + 1) : 0)
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-6-fugang.duan@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since .sg_init_one() already set sg entry page like below code.
	sg_init_one()
		sg_init_table(sg, 1);
		sg_set_buf(sg, buf, buflen);

So it should not set sg entry page again, remove the redundant code.
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-5-fugang.duan@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use kzalloc() instead of kmalloc() to get clean rx buffer
that is useful for DMA mode debug to check the data moving
validity.
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-4-fugang.duan@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add earlycon support for imx8qxp platform.
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-3-fugang.duan@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

By default, .of_dma_configure() init dev.coherent_dma_mask to BIT(32) that
match the eDMA address range. If re-init dev.coherent_dma_mask to zero, then
streaming dma mapping will go swiotlb dma_map, if swiotlb is not initalized
then it causes mapping failed.
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190717051930.15514-2-fugang.duan@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The lpuart of imx8ulp is basically the same as imx7ulp, but it
has new feature support based on imx7ulp, like it can assert a
DMA request on EOP(end-of-packet). imx8ulp lpuart use two clocks,
one is ipg bus clock that is used to access registers, the other
is baud clock that is used to transmit-receive data.
Signed-off-by: NFugang Duan <fugang.duan@nxp.com>
Link: https://lore.kernel.org/r/20190704134007.2316-1-fugang.duan@nxp.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

There is no need to add an out-of-memory error message inside
the driver because the core MM code will take care of it.

Remove the unneeded OOM error message.
Signed-off-by: NFabio Estevam <festevam@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

dev_info() is more appropriate for printing messages inside drivers, so
switch to dev_info().
Signed-off-by: NFabio Estevam <festevam@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add DMA support for 32-bit variant of the LPUART, such as LS1021A.
Signed-off-by: NTomonori Sakita <tomonori.sakita@sord.co.jp>
Signed-off-by: NAtsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The commit 3876a00fcb6b ("tty: serial: fsl_lpuart: consider TX FIFO
too in tx_empty") fixed lpuart_tx_empty only.
Fix lpuart32_tx_empty too.
Signed-off-by: NAtsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The commit 4e8f2459 ("tty: serial: fsl_lpuart: specify transmit
FIFO size") fixed lpuart_startup only.
Fix lpuart32_startup too.
Signed-off-by: NAtsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Using over-sampling ratio, lpuart can accept baud rate upto uartclk / 4.
Signed-off-by: NTomonori Sakita <tomonori.sakita@sord.co.jp>
Signed-off-by: NAtsushi Nemoto <atsushi.nemoto@sord.co.jp>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Current driver only enable parity enable bit and never clear it
when user set the termios. The fix clear the parity enable bit when
PARENB flag is not set in termios->c_cflag.

Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: NAndy Duan <fugang.duan@nxp.com>
Reviewed-by: NFabio Estevam <festevam@gmail.com>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix the typo: UARTCR1_PE -> UARTCTRL_PE
There have no function impacted since the macro define value is
the same.

Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: NAndy Duan <fugang.duan@nxp.com>
Reviewed-by: NFabio Estevam <festevam@gmail.com>
Acked-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Numbering the ttyLPn space should not depend on the generic name
"serial<n>".

If don't add the alias node like:"serial0 = &lpuart0;", then lpuart
will probe failed:
[    0.773410] fsl-lpuart 2950000.serial: failed to get alias id, errno -19

So remove the alias node dependence, and add the support for allocate the
line port automatically.
Signed-off-by: NYuan Yao <yao.yuan@nxp.com>
Signed-off-by: NVabhav Sharma <vabhav.sharma@nxp.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>