Transmit interrupts are disabled and the transmit buffer drained in the
course of console output so that polled transmission is possible.  That
however causes a lost transmit interrupt as the TxIP bit in RR3 is only
set on a transmit buffer full-to-empty transition and then iff transmit
interrupts are enabled at the same time.  Consequently if console output
disturbs a regular transmission in progress, the TxIP bit is never set
again and the transmission locks up waiting for a transmit interrupt.

Fix the problem by restarting transmission manually rather than waiting
for a transmit interrupt that will never happen.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The bcm2835 SOC contains an auxiliary uart, which is very close
to the ns16550 with some differences.

The big difference is that the uart HW is not using an internal divider
of 16 but 8, which results in an effictive baud-rate being twice
the requested baud-rate.

This driver handles this device correctly and handles the difference in
the HW divider by scaling up the clock by a factor of 2.

The approach to write a separate (wrapper) driver instead of using a
multiplying clock and "ns16550" as compatibility in the device-tree
has been recommended by Stephen Warren.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add binding documentation for the bcm2835-aux-uart driver.
Signed-off-by: Martin Sperl <kernel@martin.sperl.org>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Suspend/resume functions should work for 8250_of driver.
Signed-off-by: Wang Dongsheng <dongsheng.wang@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

DRIVER_NAME is too generic to be used in a driver-specific platform
data file. Use a name specific to the driver instead, to avoid
collisions.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The uartlite driver suffers from missing/duplicate/corrupted character
data when the interrupt handler runs concurrently with access to the
device from another cpu. Take the port spinlock to exclude concurrent
access.
Signed-off-by: Rich Felker <dalias@libc.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Microblaze currently uses the old earlyprintk system, rather than the
unified earlycon support, to show boot messages on uartlite. Add
earlycon support so that other archs using uartlite can benefit from
it. The new code in uartlite.c is copied almost verbatim from
arch/microblaze/kernel/early_printk.c.
Signed-off-by: Rich Felker <dalias@libc.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The Kconfig currently controlling compilation of this code is:

drivers/tty/serial/8250/Kconfig:config SERIAL_8250_INGENIC
drivers/tty/serial/8250/Kconfig:        bool "Support for Ingenic SoC serial ports"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Simply document new compat strings.
There appears to be no need for a driver updates.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently, when tring to set up a serial console with a higher
baud rate, it would fallback to 921600.
Tested-by: Jianqun Xu <jay.xu@rock-chips.com>
Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Add support for sparse variable sampling rates on SCIFA and SCIFB.
According to the datasheet, sampling rate 1/5 needs a small quirk to
avoid corrupting the first byte received.

This increases the range and accuracy of supported baud rates.
E.g. on r8a7791/koelsch:
  - Supports now 134, 150, and standard 500000-4000000 bps,
  - Perfect match for 134, 150, 500000, 1000000, 2000000, and 4000000
    bps,
  - Accuracy has increased for most standard bps values.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace the single sampling rate and special handling for HSCIF's
variable sampling rates by a bitmask and a custom iterator.
This prepares for the advent of SCIFA/SCIFB's sparse variable sampling
rates.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

On SCIx variants different from HSCIF, the bit rate is equal to the
sampling clock rate divided by half the sampling rate. Currently this is
handled by dividing the sampling rate by two, which was OK as it was
always even.

Replace halving the sampling rate by premultiplying the base clock
frequency by 2, to accommodate odd sampling rates on SCIFA/SCIFB later.

Replace the shift value in the BRG divider calculation by a
premultiplication of the base clock frequency too, for consistency.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

SCIFA and SCIFB have additional bit rate config bits in the Serial Mode
Register.  Don't touch them when using the port as a serial console, as
we rely on the boot loader to have configured the serial port config.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg 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: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

start_tx and the ISR used largely identical code to transmit data.
Consolidate that in one place.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove the _OFFSET suffix from all register defines which makes code a
little easier to read and avoids a few line breaks.
Suggested-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Handling magic sysrq included dropping a lock to avoid a deadlock that
happened when cdns_uart_console_write tried to acquire a lock in the
from the sysrq code path. By making the acquisition of the lock in
cdns_uart_console_write depending on port->sysrq, cdns_uart_handle_rx can be
simplified to simply call uart_handle_sysrq.
Suggested-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Convert an if-else into the more common early return on error, reducing
the indent level of the happy path.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The system could deadlock handling RX IRQs when RX-related IRQ
conditions became true while the receiver was disabled. To avoid this,
enable/disable the RX/TX IRQs together with the receiver/transmitter.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Request_irq() should be _after_ h/w programming, otherwise an
interrupt could be triggered and in-progress before the h/w has been
setup.
Reported-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Move RX-related IRQ handling into a helper function.
Fixes a problem where every char received after a parity or frame error
in the current isr will also be tagged as a parity or frame error.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Shutting down the UART port can happen while console operations are in
progress. Holding the port lock serializes these operations and avoids
the UART HW to be disabled in the middle of console prints.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The RX path in the interrupt handler released a lock unnecessarily.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The startup function is supposed to initialize the UART for receiving.
Hence, don't enable the TX part. Also, protect HW accesses with the port
lock.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

When shutting down the UART, clear the interrupt status register. Bits
in the ISR are cleared by writing them as '1'.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Restarting the transmitter even if the circ buffer is empty may be
necessary to push out remaining data when the port is restarted after
being stopped.

Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of disabling the IRQ, use the spin lock to serialize accesses to
the HW. This protects the driver from interference of non-IRQ callbacks
with each other and makes the driver more consistent in its
serialization method.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Non-functional, formatting changes to ease reading the code.
Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Moritz Fischer <moritz.fischer@ettus.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

"earlyprintk" is architecture specific option.
General "earlycon" option support is much better.
Signed-off-by: Yoshinori Sato <ysato@users.sourceforge.jp>
[uli: preserve other SCSCR bits when asserting RE and TE]
Signed-off-by: Ulrich Hecht <ulrich.hecht+renesas@gmail.com>
[geert: rewording, #ifdef rework]
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Considering that pci_pericom_setup(()'s only difference to
pci_default_setup() is the setting of the uartclk field, and taking
into account that this field already gets taken care of by having the
base_baud field filled in the pci_boards[] entries, there's no need
for both the function and the quirks table entry.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Use to_pci_dev() instead of open-coding it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

The pl011 driver has gone back and forth on the definition of the
ZTE specific variation of the hardware definitions, but the
current state is that the vendor definition is left in place
yet unused:

drivers/tty/serial/amba-pl011.c:190:27: warning: 'vendor_zte' defined but not used [-Wunused-variable]

I don't know what the plan forward is to get this code to work,
but the current behavior is a bit annoying as we get a warning
whenever we build this driver.

This patch does not help us to make it work, but at least
shuts up the warning.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 7ec75871 ("tty: amba-pl011: add support for ZTE UART (EXPERIMENTAL)")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Busy loops that poll on a register should call cpu_relax().  On some
architectures, it can lower CPU power consumption or yield to a
hyperthreaded twin processor.  It also serves as a compiler barrier,
so it can replace barrier() calls.
Signed-off-by: Timur Tabi <timur@codeaurora.org>
Reviewed-by: Dave Martin <Dave.Martin@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In datasheet, Modem Status Register MSR[4-7] reflect the modem pins
CTS/DSR/RI/CD signal state.
Signed-off-by: Wills Wang <wills.wang@live.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

In all functions other than atmel_serial_probe_fifos,
atmel_serial_probe, and atmel_console_init, the name "port" is used to
refer to an instance of struct uart_port. In many of these functions,
"atmel_port" is used to refer to an instance of struct atmel_uart_port.

We make the use of the name "port" consistent by making
atmel_serial_probe_fifos, atmel_serial_probe, and atmel_console_init
use "atmel_port" to refer to an instance of struct atmel_uart_port
instead of the previous name of "port".
Signed-off-by: Jaeden Amero <jaeden.amero@ni.com>
Signed-off-by: Kyle Roeschley <kyle.roeschley@ni.com>
Acked-by: Karthik Manamcheri <karthik.manamcheri@ni.com>
[nicolas.ferre@atmel.com: fix typo in variable, adapt to newer kernel]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Starting with sama5d2, the new UART revision has an hardware timer. So, add it
to the IP detection code and set the "has_hw_timer" property for it.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Reported-by: David Mosberger <davidm@egauge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

No functional change is associated with this patch.

A driver property depends on the Atmel serial IP revision. This property
is the way the rx timeout is handled: by an hardware or software timer.
So, change this property name and setup code so that it's easier to understand
and more future proof as the distinction of USART vs. UART is blurrier on newer
SoCs.
Variable names and debug comments are also adapted to make this code more obvious.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Some UART HW has a single register combining UART_DLL/UART_DLM
(this was probably forgotten in the change that introduced the
callbacks, commit b32b19b8)

Fixes: b32b19b8 ("[SERIAL] 8250: set divisor register correctly ...")
Signed-off-by: Sebastian Frias <sf84@laposte.net>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>