Currently, 8-bit (MMIO) and 32-bit (MMIO32) register interfaces are
supported for the 8250 console, but the 16-bit (MMIO16) is not.
The 8250 UART device on my board is connected to a 16-bit bus and
my main motivation is to use earlycon with it.
(Refer to arch/arm/boot/dts/uniphier-support-card.dtsi)
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

CIR type serial ports aren't real serial ports.

This is just a way to prevent legacy 8250 serial
driver from probing and eventually binding some
resources.

Since in current state such ports aren't providing
any real functionality and it is not possible
to change their type via setserial/ioctl(TIOCSSERIAL)
(due to UPF_FIXED_PORT flag set on them)
it is simpler and cleaner to not register them at all
with serial core.

Print a short message in this case so it is known
to user what has happened.

This way checks for PORT_8250_CIR in serial port
callbacks can be removed too, since they won't
ever be called.
Signed-off-by: NMaciej Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Preparation for uniform definition of ioremap, ioremap_wc, ioremap_wt,
and ioremap_cache, tree-wide.
Acked-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Refactor base port operations into new file; 8250_port.c.

Legacy irq handling, RSA port support, port storage for universal
driver, driver definition, module parameters and linkage remain in
8250_core.c

The source file split and resulting modules is diagrammed below:

  8250_core.c ====>   8250_core.c __
              \                     \
               \                     +-- 8250.ko (alias 8250_core)
                \     8250_pnp.c  __/     (universal driver)
                 \
                  =>  8250_port.c __
                                    \
                                     +-- 8250_base.ko
                      8250_dma.c  __/     (port operations)
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

serial8250_set_mctrl() is a void type function.  Returning something
does not look nice.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The port.fifosize member has already been copied at 8 lines above.
Maybe the compiler optimization can clean it away, but just in case.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When nr_uarts was set to 0 (via config or 8250_core.nr_uarts), we crash
early on x86 because serial8250_isa_init_ports dereferences base_ops
which remains NULL. In fact, there is nothing to do for all the callers
of serial8250_isa_init_ports if there are no uarts.

Based on suggestions by Peter Hurley.
Signed-off-by: NJan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Remove CONFIG_SERIAL_DETECT_IRQ and CONFIG_SERIAL_MANY_PORTS, and
substitute all references to the proper 8250 Kconfig options.  Now, the
actual Kconfig dependencies are not hidden when reading the code and
static analyzers are less confused.
Signed-off-by: NValentin Rothberg <valentinrothberg@gmail.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This file local CPP identifier is not referenced anywhere else, so we
can safely remove it.
Signed-off-by: NValentin Rothberg <valentinrothberg@gmail.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add cases for UPIO_MEM32BE wherever there are currently cases handling
UPIO_MEM32.
Signed-off-by: NKevin Cernekee <cernekee@gmail.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NRob Herring <robh@kernel.org>

Document the expected behavior of kernel command lines of the forms:
    console=uart[8250],io|mmio|mmio32,<addr>[,options]
    console=uart[8250],<addr>[,options]
and
    earlycon=uart[8250],io|mmio|mmio32,<addr>[,options]
    earlycon=uart[8250],<addr>[,options]
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Restore undocumented behavior of kernel command line parameters of
the forms:
    console=uart[8250],io|mmio|mmio32,<addr>[,options]
    console=uart[8250],<addr>[,options]
where 'options' have not been specified; in this case, the hardware
is assumed to be initialized.

Fixes: c7cef0a8 ("console: Add extensible console matching")
Reported-by: NYinghai Lu <yinghai@kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This adds a mapsize field to struct uart_port to be used in
conjunction with mapbase. If set, it overrides whatever value
serial8250_port_size() would otherwise report.
Signed-off-by: NMans Rullgard <mans@mansr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The serial_core.h file have been included in header file
serial_8250.h. so remove the "#include <serial_core.h>" in
some 8250 serial drivers, because they have included the header file
serial_8250.h.
Signed-off-by: NWang Long <long.wanglong@huawei.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Au1x00/RT2800+ doesn't implement the 8250 scratch register (and
this may be true of other h/w currently supported by the 8250 driver);
read back the canary value written to the scratch register to enable
the console h/w restart after resume from system suspend.

Fixes: 4516d50a ("serial: 8250: Use canary to restart console ...")
Reported-by: NMason <slash.tmp@free.fr>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Au1x00/RT2800+ hardware has an alternate register layout which is
remapped with lookup tables by the au_serial_in()/out() i/o accessors.
However, the h/w does not support the complete 8250 register set, and
accesses to unmapped registers cause out-of-bounds lookups. Further,
because the lookup tables are defined by designated initializers, the
tables may contain unmapped entries (although the current tables do not).

Declare fixed-size lookup tables with contiguous initialization for
the complete 8250 register map; unmapped registers are initialized to -1.
Validate the register index (ie., 'offset') is in the range [0, table size).
Return fixed value for unmapped register reads and ignore unmapped register
writes.
Reported-by: NMason <slash.tmp@free.fr>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-by: NMans Rullgard <mans@mansr.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The base port operations dispatch table should never be modified
at runtime; the proper way to override base port operations is
to dup the port operations, modify the copy, and point port->ops
at the copy.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; separate RSA probe and resource management
from base port operations. Override base port operations for the
config_port(), request_port() and release_port() methods to
implement the optional RSA probe and resource management only in
the universal/legacy 8250 driver.

Introduce 'probe' flags for 8250 ports, which allows drivers higher
up the driver stack to enable optional probes.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The probe for Remote Supervisor Adapter is limited to port i/o
addresses which match one of the probe_rsa[] module parameter
addresses. Limit RSA resource acquire to matching i/o ports.

The result is a saner probe policy: only perform optional probes
when specified rather than by default.

NB: It is possible for userspace to set the port type == PORT_RSA
with ioctl(TIOCSSERIAL) and then autoconfig with ioctl(TIOCSERCONFIG),
which if it fails, may leave the port type set to PORT_RSA. Since
this may have previously resulted in a working RSA port, this behavior
is preserved.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Support for Remote Supervisor Adapter is conditional on
CONFIG_SERIAL_8250_RSA; only attempt RSA resource acquire if
defined.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; move default dma tx/rx handler initialization
into serial8250_set_defaults(), which allows default dma ops to
remain unexported from the base port operations module after the split.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; move fixed type initialization into
serial8250_set_defaults(). This enables uart_config[] array to remain
file scope in base port operations after the split.

NB: the call to serial8250_init_fixed_type_port() from
serial8250_register_ports() was added by commit b5d228cc
("serial: copy UART properties of UPF_FIXED_TYPE ports provisioned
using early_serial_setup") specifically to support ports initialized
by early_serial_setup(). Since serial8250_set_defaults() is called
from early_serial_setup(), fixed type initialization is now already
handled there before serial8250_register_ports() is called.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; introduce serial8250_set_defaults() to set default
port methods prior to driver override.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; introduce serial8250_init_port() to initialize
port fields uncoupled from port structure storage.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; decouple irq setup/teardown and handler from
core port operations.

Introduce setup_irq() and release_irq() 8250 driver methods; the 8250
core will use these methods to install and remove irq handling for
the given 8250 port.

Refactor irq chain linking/unlinking from 8250 core into
univ8250_setup_irq()/univ8250_release_irq() for the universal 8250 driver.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 core split; separate shared console interface from the
console definition of the universal driver.

Introduce 8250 shared console interface; serial8250_console_write() and
serial8250_console_setup() which decouples the console operation from
the port structure storage.

Rename existing serial8250_console* identifiers to univ8250_console*.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add match() method to struct console which allows the console to
perform console command line matching instead of (or in addition to)
default console matching (ie., by fixed name and index).

The match() method returns 0 to indicate a successful match; normal
console matching occurs if no match() method is defined or the
match() method returns non-zero. The match() method is expected to set
the console index if required.

Re-implement earlycon-to-console-handoff with direct matching of
"console=uart|uart8250,..." to the 8250 ttyS console.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; initialize the port flags based on the
"skip_txen_test" module param to use the existing flag test.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250_core.c file split; move shared inline function
to local header file.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since uart->port.type has just reset to PORT_UNKNOWN, capabilities
are reset to uart_config[PORT_UNKNOWN].flags, which is 0.

Removes unnecessary dependency on uart_config[].
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

set_io_from_upio() already initializes ->handle_irq to
serial8250_default_handle_irq.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Prepare for 8250 split; calculate the ttyS index directly from
the port minor which avoids the global serial8250_reg reference
from base port operations.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

No functional changes.
Signed-off-by: NMichal Simek <michal.simek@xilinx.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This reverts commit 0aa525d1.

The conditional RX-FIFO read seems to cause spurious interrupts and we
see just:
|serial8250: too much work for irq29

The previous behaviour was "default" for decades and Marvell's 88f6282 SoC
might not be the only that relies on it. Therefore the Omap fix is
reverted for now.

Fixes: 0aa525d1 ("tty: serial: 8250_core: read only RX if there is
something in the FIFO")
Reported-By: NNicolas Schichan <nschichan@freebox.fr>
Debuged-By: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NSebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

UARTs which do not trigger THRE interrupt if the fifo is already
empty when the interrupt is enabled need tx primed manually. These
UARTs are identified by the UART_BUG_TXEN flag to enable the
required workaround.

However, the current workaround is broken; if the fifo is already
empty but the shifter is still transmitting, then serial8250_tx_chars()
will not be called but no further THRE interrupt will occur, and
tx will stall. The appropriate check is for fifo empty (THRE), not
transmitter empty (TEMT).
Signed-off-by: NDick Hollenbeck <dick@softplc.com>
[pjh: rewrote commit log]
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/8250/8250_core.c:2503:6: sparse: symbol 'serial8250_set_divisor' was not declared. Should it be static?
Signed-off-by: NFengguang Wu <fengguang.wu@intel.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The port shadow registers, ->fcr and ->mcr, must be protected from
concurrent updates. Relocate the shadow register updates in
serial8250_do_set_termios() to the port lock critical section.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using no_console_suspend, the serial console may be powered off
anyway during system sleep. Upon resume, the port may be in its default
power-on state, but is expected to continue console i/o before the device
has received its pm callback. The resultant garbage i/o can cause all
kinds of havoc on the remote end.

Use the scratch register as a canary to discover if the console
has been powered-off. Write a non-zero value to the scratch register
at port suspend and reprogram the port before any console i/o if the
scratch register != canary before port resume.

This workaround is disabled for omap_8250 (which uses different divisor
programming).

Credit to Doug Anderson <dianders@chromium.org> for the idea of using
the scratch register canary to discover port power-down.

Cc: Doug Anderson <dianders@chromium.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Exar XR17V35X PCIe uarts support a 4-bit fractional divisor register.
Refactor the divisor calculation from the divisor programming.

Allow a fractional result from serial8250_get_divisor() and pass this
result to serial8250_dl_write().

Simplify the calculation for quot and quot_frac. This was verified
to be identical to the results of the original calculation with a test
jig.

NB: The results were also compared with the divisor value chart
on pg 33 of the Exar XR17V352 datasheet, rev 1.0.3, here:
http://www.exar.com/common/content/document.ashx?id=1585
which differs from the calculated values by 1 in the fractional result.
This is because the calculated values are still rounded in the
fractional result, whereas the table values are truncated. Note
that the data error rate % values in the datasheet are for
rounded fractional results, as the truncated fractional results
have more error.

Cc: Joe Schultz <jschultz@xes-inc.com>
Cc: Aaron Sierra <asierra@xes-inc.com>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Refactor divisor register programming into a new function,
serial8250_set_divisor; this allows serial console to reinitialize
early after resume from suspend.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>