Some RS-232 devices require DTR to be asserted before they can be used.  DTR
is normally asserted in uart_startup() when the port is opened.  But we don't
actually open serial console ports, so assert DTR when the port is added.

BTW:
earlyprintk and early_uart are hard coded to set DTR/RTS.

rmk says

  The only issue I can think of is the possibility for an attached modem to
  auto-answer or maybe even auto-dial before the system is ready for it to do
  so.  Might have an undesirable cost implication for some running with such a
  setup.

  Apart from that, I can't think of any other side effect of this specific
  patch.
Signed-off-by: NYinghai Lu <yinghai.lu@sun.com>
Acked-by: NRussell King <rmk@arm.linux.org.uk>
Cc: Andi Kleen <ak@suse.de>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

serial_core, use pr_debug
Signed-off-by: NJiri Slaby <jirislaby@gmail.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

At present, the serial core always allows setserial in userspace to change the
port address, irq and base clock of any serial port.  That makes sense for
legacy ISA ports, but not for (say) embedded ns16550 compatible serial ports
at peculiar addresses.  In these cases, the kernel code configuring the ports
must know exactly where they are, and their clocking arrangements (which can
be unusual on embedded boards).  It doesn't make sense for userspace to change
these settings.

Therefore, this patch defines a UPF_FIXED_PORT flag for the uart_port
structure.  If this flag is set when the serial port is configured, any
attempts to alter the port's type, io address, irq or base clock with
setserial are ignored.

In addition this patch uses the new flag for on-chip serial ports probed in
arch/powerpc/kernel/legacy_serial.c, and for other hard-wired serial ports
probed by drivers/serial/of_serial.c.
Signed-off-by: NDavid Gibson <dwg@au1.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Serial driver patch for the PMC-Sierra MSP71xx devices.

There are three different fixes:

1 Fix for DesignWare APB THRE errata: In brief, this is a non-standard
  16550 in that the THRE interrupt will not re-assert itself simply by
  disabling and re-enabling the THRI bit in the IER, it is only re-enabled
  if a character is actually sent out.

  It appears that the "8250-uart-backup-timer.patch" in the "mm" tree
  also fixes it so we have dropped our initial workaround.  This patch now
  needs to be applied on top of that "mm" patch.

2 Fix for Busy Detect on LCR write: The DesignWare APB UART has a feature
  which causes a new Busy Detect interrupt to be generated if it's busy
  when the LCR is written.  This fix saves the value of the LCR and
  rewrites it after clearing the interrupt.

3 Workaround for interrupt/data concurrency issue: The SoC needs to
  ensure that writes that can cause interrupts to be cleared reach the UART
  before returning from the ISR.  This fix reads a non-destructive register
  on the UART so the read transaction completion ensures the previously
  queued write transaction has also completed.
Signed-off-by: NMarc St-Jean <Marc_St-Jean@pmc-sierra.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since serial devices are powered down when not in use and some of those
devices cannot be accessed when powered down, we need to enable power
around calls to get_mcrtl() when dumping port state via uart_line_info().
This resolves hangs observed on some machines while reading serial device
registers when a port is powered off.
Signed-off-by: NGeorge G. Davis <gdavis@mvista.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is the grungy swap all the occurrences in the right places patch that
goes with the updates.  At this point we have the same functionality as
before (except that sgttyb() returns speeds not zero) and are ready to
begin turning new stuff on providing nobody reports lots of bugs

If you are a tty driver author converting an out of tree driver the only
impact should be termios->ktermios name changes for the speed/property
setting functions from your upper layers.

If you are implementing your own TCGETS function before then your driver
was broken already and its about to get a whole lot more painful for you so
please fix it 8)

Also fill in c_ispeed/ospeed on init for most devices, although the current
code will do this for you anyway but I'd like eventually to lose that extra
paranoia

[akpm@osdl.org: bluetooth fix]
[mp3@de.ibm.com: sclp fix]
[mp3@de.ibm.com: warning fix for tty3270]
[hugh@veritas.com: fix tty_ioctl powerpc build]
[jdike@addtoit.com: uml: fix ->set_termios declaration]
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NMartin Peschke <mp3@de.ibm.com>
Acked-by: NPeter Oberparleiter <oberpar@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: NHugh Dickins <hugh@veritas.com>
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

As part of an SMP cleanliness pass over UML, I consted a bunch of
structures in order to not have to document their locking.  One of these
structures was a struct tty_operations.  In order to const it in UML
without introducing compiler complaints, the declaration of
tty_set_operations needs to be changed, and then all of its callers need to
be fixed.

This patch declares all struct tty_operations in the tree as const.  In all
cases, they are static and used only as input to tty_set_operations.  As an
extra check, I ran an i386 allyesconfig build which produced no extra
warnings.

53 drivers are affected.  I checked the history of a bunch of them, and in
most cases, there have been only a handful of maintenance changes in the
last six months.  serial_core.c was the busiest one that I looked at.
Signed-off-by: NJeff Dike <jdike@addtoit.com>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

A serial card might have been removed when the system is resumed.
This results in a suspended port being shut down, which results in
the ports shutdown method being called twice in a row.  This causes
BUGs.  Avoid this by tracking the suspended state separately from
the initialised state.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix the issue of returning 0 even in case of error from uart_set_info
function.  Now it returns the error EBUSY when it can not set new port.
Signed-off-by: NRam Gupta <r.gupta@astronautics.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

/proc/tty/driver/serial incorrectly claims that UARTs having iotype of
UPIO_MEM32, UPIO_AU, or UPIO_TSI are I/O mapped.
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Hack uart_suspend_port() and uart_resume_port() so that serial console
ports are not suspended if CONFIG_DISABLE_CONSOLE_SUSPEND is set.

This makes it possible to debug the suspend and resume routines of all
device drivers as well as the lowest-level swsusp code with the help of the
serial console.
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Acked-by: NPavel Machek <pavel@ucw.cz>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

uart_match_port() always fails with UPIO_MEM32, UPIO_AU, and UPIO_TSI cases.
Since they match to the memory mapped UARTs, they should be handled just like
UPIO_MEM case.
Signed-off-by: NSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The following patch gets rid of CONFIG_TSI108_BRIDGE.  I add UPIO_TSI to
handle IIR and IER register in serial_in and serial_out.

(1) the reason to rewrite serial_in:

    TSI108 rev Z1 version ERRATA.  Reading the UART's Interrupt
    Identification Register (IIR) clears the Transmit Holding Register
    Empty (THRE) and Transmit buffer Empty (TEMP) interrupts even if they
    are not enabled in the Interrupt Enable Register (IER).  This leads to
    loss of the interrupts.  Interrupts are not cleared when reading UART
    registers as 32-bit word.

(2) the reason to rewrite serial_out:

    Check for UART_IER_UUE bit in the autoconfig routine.  This section
    of autoconfig is excluded for Tsi108/109 because bits 7 and 6 are
    reserved for internal use.  They are R/W bits.  In addition to
    incorrect identification, changing these bits (from 00) will make
    Tsi108/109 UART non-functional.
Signed-off-by: NRoy Zang <tie-fei.zang@freescale.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Teach special (dual-initialized) locking code to the lock validator.  Has no
effect on non-lockdep kernels.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Some UARTs have more than 255 bytes of FIFO, which can't be
represented by an unsigned char.  Change the kernel's internal
structure to be an unsigned int, but still export an unsigned char
via the TIOCGSERIAL ioctl.  If the TIOCSSERIAL ioctl provides a
fifo size of 0, assume this means "don't change" otherwise we'll
corrupt the larger fifo sizes.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Signed-off-by: NJörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: NAdrian Bunk <bunk@stusta.de>

I've always found this flag confusing.  Now that devfs is no longer around, it
has been renamed, and the documentation for when this flag should be used has
been updated.

Also fixes all drivers that use this flag.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Also fixes all serial drivers.
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Patch from Andrew Victor

The serial_core already manages the power state of the UARTs, and
therefore it shouldn't suspend a UART which was previously suspended.

This patch modifies serial_core only call the UART-specific
power-management function if the PM state is actually changing.
Signed-off-by: NAndrew Victor <andrew@sanpeople.com>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The locking for the uart_port is over complicated, and can be
simplified if we introduce a flag to indicate that a port is "dead"
and will be removed.

This also helps the validator because it removes a case of non-nested
unlock ordering.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.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>

We're presently getting oopses because Bluetooth (and possibly other) drivers
are calling core functions after things have been shut down.

So rather than oopsing, let's drop a warning then take avoiding action, so the
machine survives.  Once all the sub-drivers are fixed up we can remove the
take-avoiding-action part.
Signed-off-by: NPavel Machek <pavel@suse.cz>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

It seems serial_core intend to initialize port->lock just once for each
ports.  This is done in uart_set_options() for console, and in
uart_add_one_port() for other ports.  But there is a case the port->lock is
not initialized by serial_core.  If the setup function for the console was
failed, it will not call uart_set_options() but the port is marked as
console (uart_console(port) returns 1).  It can happen if console was PCI
port which can not detected at the time of register_console.

This patch is to initialize port->lock for such console port.  With this
change, most of spin_lock_init() (some of them are labeled "Temporary
fix.") in low-level serial drivers can be omitted.
Signed-off-by: NAtsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Same reasoning as commit 747c8a55
but this time we're making uart_port flags a bitwise type - not
all of these flags correspond with the old ASYNC_ flags, so there
is the possibility for bugs if the wrong ASYNC_* constants are
used.  Always use UPF_* constants for uart_port->flags.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

No one should write to the port->ops structure, so make it constant.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

semaphore to mutex conversion.

the conversion was generated via scripts, and the result was validated
automatically via a script as well.

build and boot tested.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Turn several drivers/serial/ semaphores-used-as-mutex into mutexes
Signed-off-by: NArjan van de Ven <arjan@infradead.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Jim Alexander reported a problem where "if one calls open() in
blocking mode with CLOCAL off, the 8250.c driver under the 2.6
kernel (or at least 2.6.8 and 2.6.10) does not wake up the
blocked process when DCD is asserted."

Fix this by enabling modem status interrupts immediately before
we read the carrier detect status.

Thanks to Jim for reporting the problem and testing the fix.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The function uart_match_port() incorrectly compares the ioremap'd
virtual addresses of ports instead of the physical address to find
duplicate ports for MMIO based UARTs. This fixes it.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch marks a few serial data structures const, moving them to
.rodata where they won't false-share cachelines with things that get
written to.
Signed-off-by: NArjan van de Ven <arjan@infradead.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

If we fail to re-startup a serial port on resume, shut it down
immediately and mark it as an error condition.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

The offsets of the registers are in a different place, and
some parts cannot handle a full set of modem control signals.
Signed-off-by: NPantelis Antoniou <pantelis@embeddedalley.ocm>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Folk seem to get confused when they see two or more ttyS0 ports
appearing at boot time.  One comes from the legacy table, and
one from PNP.

Hence, display the bus ID of the device which supplied the port.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch fixes an issue reported by Coverity in serial/serial_core.c

Error reported: Variable "&((info)->tty)->flags" tracked as NULL was passed to a
function that dereferences it.

The later statements in the function assumes 'info->tty != NULL', so this
check is not necessary.  Probably a 'BUG_ON(info->tty == NULL)' can be added.

Signed-off-by: Jayachandran C. <c.jayachandran at gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Pre-format the IO part of the ttyS printks, and prefix them with
KERN_INFO to avoid bootsplash corruption.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Patch from Sascha Hauer

This patch adds support for setting and getting RTS / CTS via
set_mtctrl / get_mctrl functions.
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Initialise the spinlock for port being used by the console early, but
don't re-initialise it again later.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

Fix bugme #4712: read the CTS status and set hw_stopped if CTS
is not active when opening the port and/or enabling CRTSCTS

Thanks to Stefan Wolff for spotting this problem.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>

This patch changes the way serial ports are locked when getting modem
status.  This change is necessary because we will need to atomically
read the modem status and take action depending on the CTS status.
Signed-off-by: NRussell King <rmk+kernel@arm.linux.org.uk>