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>

Now, wait_for_xmitr() is only called from serial_putc(), and both
are short enough.  They can be merged into a single function.
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>

The current code waits until the transmitter becomes empty,
before sending each character, and after finishing the whole string.
This seems a bit redundant.

It can be more efficient by checking the transmitter only after sending
each character.  This should be safe because the transmitter is already
empty at the first entry of serial_putc().
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>

The IER has already been masked in early_serial8250_setup(), there is
no reason to save and restore it every time early_serial8250_write()
is called.
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>

This allows earlycon to be used without needing to specify the I/O
address on the kernel command line, if linux,stdout-path is specified
in the chosen node.
Signed-off-by: NScott Wood <scottwood@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit ed71871b ("tty/8250_early: Turn serial_in/serial_out into
weak symbols") made these routines weak to allow platform specific
Big endian override

However recent updates to core, specifically ebc5e200 ("serial:
of_serial: Support big-endian register accesses") and 6e63be3f
("serial: earlycon: Add support for big-endian MMIO accesses") means
that round about way to overide the early serial accessors is no longer
needed.

Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Kevin Cernekee <cernekee@gmail.com>
Acked-by: NNoam Camus <noamc@ezchip.com>
Signed-off-by: NVineet Gupta <vgupta@synopsys.com>
Reviewed-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

8250-like uart driver may call early_serial8250_setup to
reuse 8250_early.c character output function.
Signed-off-by: NEddie Huang <eddie.huang@mediatek.com>
Tested-by: NSascha Hauer <s.hauer@pengutronix.de>
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>

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>

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>

setup_earlycon() will now match and register the desired earlycon
from the param string (as if 'earlycon=...' had been set on the
command line). Use setup_earlycon() from existing arch call sites
which start an earlycon directly.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Earlycon matching can only be triggered if 'earlycon=...' has been
specified on the kernel command line. To workaround this limitation
requires tight coupling between arches and specific serial drivers
in order to start an earlycon. Devicetree avoids this limitation
with a link table that contains the required data to match earlycons.

Mirror this approach for earlycon match by name. Re-purpose
EARLYCON_DECLARE to generate a table entry which associates name with
setup() function. Re-purpose setup_earlycon() to scan this table for
an earlycon match, which is registered if found.

Declare one "earlycon" early_param, which calls setup_earlycon().

This design allows setup_earlycon() to be called directly with a
param string (as if 'earlycon=...' had been set on the command line).
Re-registration (either directly or by early_param) is prevented.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If parsing failed to decode a valid uart addr, return -ENODEV instead
of success. Although setup_earlycon() will detect the failure anyway
(because the write() method has not been set), that behavior is not
obvious and should not be relied on.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The <baud><parity><bit> option string is not supplied if the earlycon
is started via devicetree and OF_EARLYCON_DECLARE(). The option string
is also not required if started via kernel command line parameters of
the form:
  earlycon=uart,mmio,<addr>
  console=uart,mmio,<addr>

If earlycon_device->baud is 0, then an option string was not supplied.
In this case, assume the uart has already been initialized by the
bootloader or firmware.
Acked-by: NRob Herring <robh@kernel.org>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

early_device was only required for serial8250_find_port_for_earlycon(),
which was replaced by extensible console matching.

Fixup early_serial8250_write() to get the earlycon_device * from
console->data (which is initialized by {of_}setup_earlycon()).
Acked-by: NRob Herring <robh@kernel.org>
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>

The PXA variant of the 8250 UART adds a UART enable bit which must not
be cleared. Make the earlycon support maintain this bit if it is set.
This implies some initialization of the UART, but we cannot
unconditionally set the bit as some other variants require this bit to
be clear for other functions.
Signed-off-by: NRob Herring <robh@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
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>

In the conversion to generic early console, the passing of options from
the early 8250 console to the regular ttyS console was broken. This
resulted in the baud rate changing when switching consoles during boot.

This feature allows specifying a single console option on the kernel
command line rather than both an early console and regular serial tty
console. It would be nice to generalize this feature. However, it only
works if the correct baud rate can be probed early which is not the
case on many platforms which have non-standard UART clock rates. So for
now, this is left as an 8250 specific feature.
Reported-and-tested-by: NTony Luck <tony.luck@intel.com>
Signed-off-by: NRob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit d2fd6810 (tty/serial: convert 8250 to generic earlycon)
removed setup_early_serial8250_console, but there are still 2 callers
in:

arch/mips/mti-malta/malta-init.c
drivers/firmware/pcdp.c

Add back the function implemented as a wrapper to setup_earlycon.
Reported-by: NYinghai Lu <yinghai@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

With the generic earlycon infrastructure in place, convert the 8250
early console to use it.
Signed-off-by: NRob Herring <robh@kernel.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Fix the following sparse warning:

drivers/tty/serial/8250/8250_early.c:196:26: error: incompatible types in comparison expression (different type sizes)
Signed-off-by: NJingoo Han <jg1.han@samsung.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The earlier change to use strlcpy uncovered a bug in the options
argument length calculation causing last character to be truncated.
This makes the actual console to be configured with incorrect
baudrate when specifying the console using console=uart,... syntax.

Bug symptom seen in kernel log output:

Kernel command line: console=uart,mmio,0x90000000,115200
Early serial console at MMIO 0x90000000 (options '11520')

which then results in a invalid baud rate 11520 instead of the
expected 115200 when the console is switched to ttyS0 later
in the boot process.
Signed-off-by: NHenrik Nordstrom <henrik@henriknordstrom.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

  The fields must be null-terminated, or next printk for %s, will cause issue.
Signed-off-by: NChen Gang <gang.chen@asianux.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Allows overriding default methods serial_in/serial_out.

In such platform specific replacement it is possible to use
other regshift, biased register offset, any other manipulation
that is not covered with common default methods.

Overriding default methods may be useful for platforms which got
serial peripheral with registers represented in big endian.
In this situation and assuming that 32 bit operations / alignment
is required then it may be useful to swab words before/after
accessing the serial registers.
Signed-off-by: NNoam Camus <noamc@ezchip.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Modify divisor to select the nearest baud rate divider rather than the
lowest. It minimizes baud rate errors especially on low UART clock
frequencies.

For example, if uartclk is 33000000 and baud is 115200 the ratio is
about 17.9 The current code selects 17 (5% error) but should select 18
(0.5% error).

This 5% error in baud rate leads to garbage on receiving end, while 0.5%
doesn't.

The issue showed up when using the stock 8250 driver for
Synopsys DW UART. This was on a FPGA with ~12MHz UART clock.
When we enabled early serial, we saw garbage which was narrowed down
to the rounding error.

So the bug had been latent and it only showed up with such low clock rates.
Signed-off-by: NAlexey Brodkin <abrodkin@synopsys.com>
Acked-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The drivers/tty/serial dir is already getting rather busy.
Relocate the 8250 related drivers to their own subdir to
reduce the clutter.

Note that sunsu.c is not included in this move -- it is
8250-like hardware, but it does not use any of the existing
infrastructure -- and does not depend on SERIAL_8250.
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The serial drivers are really just tty drivers, so move them to
drivers/tty/ to make things a bit neater overall.

This is part of the tty/serial driver movement proceedure as proposed by
Arnd Bergmann and approved by everyone involved a number of months ago.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Rogier Wolff <R.E.Wolff@bitwizard.nl>
Cc: Michael H. Warfield <mhw@wittsend.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Device addresses are usually printed in hex.
Signed-off-by: NTony Luck <tony.luck@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Provide MMIO32 support in 8250_early (aka earlycon)

[randy.dunlap@oracle.com: fix printk format warnings]
[akpm@linux-foundation.org: fix printk args some more]
Signed-off-by: NSamium Gromoff <_deepfire@feelingofgreen.ru>
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NAlan Cox <alan@redhat.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

__FUNCTION__ is gcc-specific, use __func__
Signed-off-by: NHarvey Harrison <harvey.harrison@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

drivers/serial/8250_early.c:80: warning: conflicting types for built-in function `putc'
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

the early setup function serial8250_console_early_setup() can be called
from non __init code (eg. hotpluggable serial ports like serial_cs) so
remove the __init from the call chain to avoid crashes.
Signed-off-by: NDaniel Ritz <daniel.ritz@gmx.ch>
Cc: Yinghai Lu <yinghai.lu@sun.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

At present, various parts of the serial code use unsigned long to define
resource addresses.  This is a problem, because some 32-bit platforms have
physical addresses larger than 32-bits, and have mmio serial uarts located
above the 4GB point.

This patch changes the type of mapbase in both struct uart_port and struct
plat_serial8250_port to resource_size_t, which can be configured to be 64
bits on such platforms.  The mapbase in serial_struct can't safely be
changed, because that structure is user visible.
Signed-off-by: NDavid Gibson <dwg@au1.ibm.com>
Signed-off-by: NJosh Boyer <jwboyer@linux.vnet.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and
include/asm-x86_64/serial.h.  the serial8250_ports need to be probed late in
serial initializing stage.  the console_init=>serial8250_console_init=>
register_console=>serial8250_console_setup will return -ENDEV, and console
ttyS0 can not be enabled at that time.  need to wait till uart_add_one_port in
drivers/serial/serial_core.c to call register_console to get console ttyS0.
that is too late.

Make early_uart to use early_param, so uart console can be used earlier.  Make
it to be bootconsole with CON_BOOT flag, so can use console handover feature.
and it will switch to corresponding normal serial console automatically.

new command line will be:
	console=uart8250,io,0x3f8,9600n8
	console=uart8250,mmio,0xff5e0000,115200n8
or
	earlycon=uart8250,io,0x3f8,9600n8
	earlycon=uart8250,mmio,0xff5e0000,115200n8

it will print in very early stage:
	Early serial console at I/O port 0x3f8 (options '9600n8')
	console [uart0] enabled
later for console it will print:
	console handover: boot [uart0] -> real [ttyS0]

Signed-off-by: <yinghai.lu@sun.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Glen Turner reported that writing LFCR rather than the more
traditional CRLF causes issues with some terminals.

Since this aflicts many serial drivers, extract the common code
to a library function (uart_console_write) and arrange for each
driver to supply a "putchar" function.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix sparse warning about passing `0` to  simple_strtoul()
Signed-off-by: NBen Dooks <ben-linux@fluff.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!