Perform a tricky suspend/resume even with no_console_suspend.

With no_console_suspend, kernel skips serial port suspend/resume and the
serial hardware may remain in undefined state after resume. It actually
happens on devices that don't have BIOS that handle serial
initialization. It makes impossible to use serial console after resume.

Devices affected by this problem include:
Sharp Zaurus devices
Several PXA based ARM embedded boards

The patch does:
- Save the hardware state
- Perform buffer flush in time of its suspend call
- Tell the driver that port is suspended
- But still accept new data
- And keep console hardware in state that allows to send them

It allows to capture late console messages without breaking console
after resume.

This is just a resend of a patch discussed in these threads, as the
patch was not yet applied.

"Possible suspend/resume regression in .32-rc?" (Nov 1-5, 2009, ARM
list, later LKML)

"serial-core: resume serial hardware with no_console_suspend" (Sep
15-Oct 18, 2009, LKML & ARM lists)
Signed-off-by: NStanislav Brabec <sbrabec@suse.cz>
Tested-by: NHaojian Zhuang <haojian.zhuang@gmail.com>
Tested-by: NDaniel Mack <daniel@caiaq.de>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

If kzalloc() or alloc_tty_driver() fails, we call:
    put_tty_driver(normal = NULL).

Then:
    put_tty_driver -> tty_driver_kref_put -> kref_put(&NULL->kref, ...)
Signed-off-by: NAndré Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Commit 46d57a44 ("serial: use tty_port pointers in the core code")
contained two bugs that causes (rare) crashes:

 - the rename typoed one site

 - a NULL check was missed
Reported-and-tested-by: NIngo Molnar <mingo@elte.hu>
Cc: Greg KH <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix new kernel-doc warnings in serial_core.[hc] files.

  Warning(include/linux/serial_core.h:485): No description found for parameter 'uport'
  Warning(include/linux/serial_core.h:485): Excess function parameter 'port' description in 'uart_handle_dcd_change'
  Warning(include/linux/serial_core.h:511): No description found for parameter 'uport'
  Warning(include/linux/serial_core.h:511): Excess function parameter 'port' description in 'uart_handle_cts_change'
  Warning(drivers/serial/serial_core.c:2437): No description found for parameter 'uport'
  Warning(drivers/serial/serial_core.c:2437): Excess function parameter 'port' description in 'uart_add_one_port'
  Warning(drivers/serial/serial_core.c:2509): No description found for parameter 'uport'
  Warning(drivers/serial/serial_core.c:2509): Excess function parameter 'port' description in 'uart_remove_one_port'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit b5b82df6, from May 2007, breaks no_console_suspend on the OLPC
XO laptop. Basically what happens is that upon returning from resume,
serial8250_resume_port() will reconfigure the port for high speed
mode and all console output will be garbled, making debug of the
resume path painful. This patch modifies uart_resume_port() to
reset the port to the state it was in before we suspended.

Original patch by Marcelo Tosatti

Second patch by Deepak then reworked by Alan to fit with the tty changes
before it got submitted. Also fixed the console path to set c_i/ospeed as
some drivers require the termios fields are valid
Signed-off-by: NDeepak Saxena <dsaxena@laptop.org>
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Initially just use the helper and thus krefs when we set and clear the
port values.
Signed-off-by: NAlan Cox <alan@linux.intel.com>

The serial layer for some reason uses different defines for the special
case close delays and then conditionally switches to/from the normal ones
in the ioctls.

Remove this rather pointless abstraction
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This little helper is now tty_port specific and useful generally so move it
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

This is used by various drivers not just serial and can be extracted
as commonality
Signed-off-by: NAlan Cox <alan@linux.intel.com>

They cover essentially the same stuff and we can therefore fold it into the
tty_port one.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Fortunately the serial layer was designed to use the same flag values but
with different names. It has its own SUSPENDED flag which is a free slot in
the ASYNC flags so we allocate it in the ASYNC flags instead.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Remove more stuff from the serial special case code
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Extract out a lot of the x.port. uses and also show up where there are
things left to be isolated that prevent use using the port helpers in the
serial layer at this point
Signed-off-by: NAlan Cox <alan@linux.intel.com>

Remove some more serial specific use
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

We moved this into uart_state, now move the fields out of the separate
structure and kill it off.
Signed-off-by: NAlan Cox <alan@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

"struct tty_driver *" lies in m->private not in v which is
SEQ_TOKEN_START which is 1 which is enough to trigger NULL dereference
next line:

	BUG: unable to handle kernel NULL pointer dereference at 000000ad
	IP: [<c040d689>] uart_proc_show+0xe/0x2b0

Noticed by Linus.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
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>

Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

Add flag value UPF_FIXED_TYPE which specifies that the UART type is
known and should not be probed.  For this case the UARTs properties
are just copied out of the uart_config entry.

This allows us to keep SOC specific 8250 probe code out of 8250.c.  In
this case we know the serial hardware will not be changing as it is on
the same silicon as the CPU, and we can specify it with certainty in
the board/cpu setup code.

The alternative is to load up 8250.c with a bunch of OCTEON specific
special cases in the probing code.
Signed-off-by: NDavid Daney <ddaney@caviumnetworks.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Hi Alan

next-20081204 crashes with the following message:

BUG: unable to handle kernel paging request at ffff88007d320248
IP: [<ffffffff803de934>] uart_remove_one_port+0xef/0x111
                kfree(info);
     393:       49 8d 7d 10             lea    0x10(%r13),%rdi
     397:       e8 00 00 00 00          callq  39c <uart_remove_one_port+0xef>
Signed-off-by: NAlexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the tty_port and uart_info bits around a little. By embedding the uart_info
into the uart_port we get rid of lots of corner case testing and also get the
ability to go port<->state<->info which is a bit more elegant than the current
data structures.

Downsides - we allocate a tiny bit more memory for unused ports, upside we've
removed as much code as it saved for most users..
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NYinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

The multiple drivers share the minor space occupied by a particular major
number, the actual index within the device name's space is indicated by
the tty_driver->name_base + uart_port->line

Another usable formula is (uart_driver->minor - MINOR_BASE) + port->line

Use those to print the device names properly in such situations in
serial_core.c and 8250.c
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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

Some hardware needs to do break handling itself and may have partial
support only. Make break_ctl return an error code. Add a tty driver flag
so you can indicate driver hardware side break support.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Switch the serial_core based drivers to use the new tty_port structure.
We can't quite use all of it yet because of the dynamically allocated
extras in the serial_core layer.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Serial drivers using DMA (like the atmel_serial driver) tend to get very
confused when the xmit buffer is flushed and nobody told them.  They
also tend to spew a lot of garbage since the DMA engine keeps running
after the buffer is flushed and possibly refilled with unrelated data.

This patch adds a new flush_buffer operation to the uart_ops struct,
along with a call to it from uart_flush_buffer() right after the xmit
buffer has been cleared. The driver can implement this in order to
syncronize its internal DMA state with the xmit buffer when the buffer
is flushed.
Signed-off-by: NHaavard Skinnemoen <haavard.skinnemoen@atmel.com>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As reported by Vipul Gandhi, the current serial_match_port() doesn't work
for tty-devices using dynamic major number allocation.  Fix it.

It oopses if you suspend a serial port with _dynamic_ major number.  ATM,
I think, there's only the drivers/serial/jsm/jsm_driver.c driver, that
does it in-tree.
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Tested-by: NVipul Gandhi <vcgandhi1@aol.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 64e9159f ("serial_core:
uart_set_ldisc infrastructure") introduced the ability for low-level
serial drivers to be informed when the tty ldisc changes.

However, the actual tty-layer function that does this callback for
serial devices was declared with the wrong type, having a spurious and
unused 'ldisc' argument.

This fixed the resulting compiler warning by just removing it.
Acked-by: NBlithering Idiot <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The tty layer provides a callback that is used when the line discipline
is changed. Some hardware uses this to configure hardware specific
features such as IrDA mode on serial ports. Unfortunately the serial
layer does not provide this feature or pass it down to drivers.

Blackfin used to hack around this by rewriting the tty ops, but those are
now properly shared and const so the hack fails. Instead provide the
proper operations.

This change plus a follow up from the Blackfin guys is needed to avoid
blackfin losing features in this release.
Signed-off-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

enable_irq_wake() and disable_irq_wake() need to be balanced.  However,
serial_core.c calls these for different conditions during the suspend and
resume functions...

This is causing a regular WARN_ON() as found at
http://www.kerneloops.org/search.php?search=set_irq_wake

This patch makes the conditions for triggering the _wake enable/disable
sequence identical.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
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>

I noticed that

  static void uart_flush_buffer(struct tty_struct *tty)
  {
  	struct uart_state *state = tty->driver_data;
  	struct uart_port *port = state->port;
  	unsigned long flags;

  	/*
  	 * This means you called this function _after_ the port was
  	 * closed.  No cookie for you.
  	 */
  	if (!state || !state->info) {
  		WARN_ON(1);
  		return;
  	}

is too late for checking state != NULL.
Signed-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

- Operations are now a shared const function block as with most other Linux
  objects

- Introduce wrappers for some optional functions to get consistent behaviour

- Wrap put_char which used to be patched by the tty layer

- Document which functions are needed/optional

- Make put_char report success/fail

- Cache the driver->ops pointer in the tty as tty->ops

- Remove various surplus lock calls we no longer need

- Remove proc_write method as noted by Alexey Dobriyan

- Introduce some missing sanity checks where certain driver/ldisc
  combinations would oops as they didn't check needed methods were present

[akpm@linux-foundation.org: fix fs/compat_ioctl.c build]
[akpm@linux-foundation.org: fix isicom]
[akpm@linux-foundation.org: fix arch/ia64/hp/sim/simserial.c build]
[akpm@linux-foundation.org: fix kgdb]
Signed-off-by: NAlan Cox <alan@redhat.com>
Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
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>

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

Instead of checking for the BKL in these methods, take it ourselves.  That
avoids propogating it into the serial drivers and we can then fix them later
on.
Signed-off-by: NAlan Cox <alan@redhat.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>

Russell King noticed this one: We have to avoid replacing B0 when we pick a
baud rate for a "hung up" port.  Ugly but the proper fix is in the tty layer
and means changing the tty<->serial interfaces so we will defer that for now.

[akpm@linux-foundation.org: fix uninitialised var]
Signed-off-by: NAlan Cox <alan@redhat.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>

This patch (as1059) fixes a mistake in the way the serial core
initializes a device's wakeup settings.  It should use the accessor
routine instead of relying on a macro producing an lvalue.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

ERROR: "uart_parse_options" [drivers/serial/serial_core.ko] undefined!

Cc: Jason Wessel <jason.wessel@windriver.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

polled console handling support, to access a console in an irq-less
way while in debug or irq context.

absolutely zero impact as long as CONFIG_CONSOLE_POLL is disabled.
(which is the default)

[ jan.kiszka@siemens.com: lots of cleanups ]
[ mingo@elte.hu: redesign, splitups, cleanups. ]
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NJan Kiszka <jan.kiszka@web.de>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>