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Commit Graph

20 Commits

Author SHA1 Message Date
Jiri Slaby
0b058353ab TTY: use tty_wait_until_sent_from_close in other drivers
Let's use the newly added helper to avoid stalls in drivers which are
not yet ported to tty_port helpers.

Those which are broken (call tty_wait_until_sent with irqs disabled)
are left untouched. They are in a deeper trouble than we are trying to
solve here. This includes amiserial, 68328serial, 68360serial and
crisv10.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-25 09:00:42 -07:00
Jiri Slaby
bafb0bd24d TTY: serial, move locking in uart_close
So now, when we handle CLOSING flag, there is no point to hold
port->mutex over the start of uart_close.

Yes, there are still several things to reason about:
* port->count etc is and always was protected by a spinlock
* ->stop_rx is protected by a spinlock. Otherwise it would
  race with interrupts.
* uart_wait_until_sent -- that one is already called without
  port->mutex from set_termios and tty_set_ldisc. Should anything
  be protected there, it would be tx_empty. And by a spinlock.
  8250 does this internally...

This step is needed to fix system stalls. To not create an AB-BA lock
dependency (see next patches).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-25 09:00:39 -07:00
Jiri Slaby
426929f8d3 TTY: serial, use ASYNCB_CLOSING in uart_close
We need to move port->mutex locking after wait_until_sent in
uart_close (for rationale see next patches). But if we did it now, we
would introduce a race between close and open. This is exactly why
port->mutex is locked at the top of uart_close.

To avoid the race, we add ASYNCB_CLOSING to uart_close. Like every
other sane TTY driver. Thanks to tty_port_block_til_ready used in
uart_open we will have this for free. Then we can move the port->mutex
lock.

Also note that this will make the conversion to tty_port helpers
easier. They are currently handling ASYNC_CLOSING flag correctly.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-25 09:00:39 -07:00
Jamie Iles
4834d02897 tty: serial8250: remove UPIO_DWAPB{,32}
Now that platforms can override the port IRQ handler and the only user
of these UPIO modes has been converted over, kill off UPIO_DWAPB and
UPIO_DWAPB32.

Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-23 10:53:00 -07:00
Jiri Slaby
906cbe1364 TTY: remove tty_locked
We used it really only serial and ami_serial. The rest of the
callsites were BUG/WARN_ONs to check if BTM is held. Now that we
pruned tty_locked from both of the real users, we can get rid of
tty_lock along with __big_tty_mutex_owner.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-23 10:34:07 -07:00
Jiri Slaby
6a3e492b6d TTY: serial, remove tasklet for tty_wakeup
tty_wakeup can be called from any context. So there is no need to have
an extra tasklet for calling that. Hence save some space and remove
the tasklet completely.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-23 10:34:06 -07:00
Jiri Slaby
1f33a51d97 TTY: serial, remove BTM from wait_until_sent
During the BKL removal process, the BKL was switched to tty_lock
(BTM). Now we should start pruning the BTM further. Let's start with
wait_until_sent of the serial layer. This will allow us to switch to
the tty port helpers and thus clean it up much.

In wait_until_sent there are some uport members accessed, but neither
of them is protected by BTM at the location they are set ('=>' means
function call):
* uport->fifosize (set in tty_ioctl => uart_ioctl => uart_set_info)
* uport->type (set in add_one_port prior to tty_register_device)
* uport->timeout (set usually in tty_ioctl => tty_mode_ioctl =>
  tty_set_termios => uart_set_termios => uart_change_speed =>
  uport->ops->set_termios => uart_update_timeout)
* call to uport->ops->tx_empty()

If the tx_empty hook needs some lock to protect accesses to registers,
it should take &uport->lock spinlock like 8250 does. Otherwise there
still might be races e.g. with ISRs.

This should also fix the issue Andreas is seeing (BTM in comparison to
BKL doesn't have any hidden functionality like unlocking during
sleeping).

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
References: https://lkml.org/lkml/2011/5/25/562
Cc: Alan Cox <alan@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Andreas Bombe <aeb@debian.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-08-23 10:34:05 -07:00
Jiri Slaby
c831cff256 TTY: serial_core, remove superfluous set_task_state
msleep* is guaranteed to return with TASK_RUNNING task state. And
since there is no other set_task_state in the paths of
uart_wait_until_sent, we need not to set_task_state to TASK_RUNNING.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-25 14:19:12 -07:00
Jiri Slaby
32ad3a77b2 TTY: serial_core, remove invalid test
tty->index (named here as line) is set up in initialize_tty_struct.
The value is checked in get_tty_driver for the found driver as:
	if (device < base || device >= base + p->num)
		continue;
	*index = device - base;

So index/line can never be more than driver->num. Hence remove this
test from uart_open.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-25 14:19:11 -07:00
Govindraj.R
e9a470f445 Serial: Remove unused code.
Remove stale code in serial_core layer.

Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:33:37 -07:00
Jovi Zhang
99edb3d10a tty: remove invalid location line in file header
remove invalid location line in each file header after location
moved from driver/char to driver/tty

Signed-off-by: Jovi Zhang <bookjovi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:33:36 -07:00
Jiri Slaby
6f5c24ad0f serial: core, remove uart_update_termios
Now, uart_update_termios is empty, so it's time to remove it. We no
longer need a live tty in .dtr_rts. So this should prune all the bugs
where tty is zeroed in port->tty during tty_port_block_til_ready.

There is one thing to note. We don't set ASYNC_NORMAL_ACTIVE now. It's
because this is done already in tty_port_block_til_ready.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:32:20 -07:00
Jiri Slaby
303a7a1199 serial: core, do not set DTR/RTS twice on startup
In .dtr_rts we do:
  uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS)
and call uart_update_termios. It does:
  uart_set_mctrl(port, TIOCM_DTR | TIOCM_RTS)
once again. As the only callsite of uart_update_termios is .dtr_rts,
remove the uart_set_mctrl from uart_update_termios to not set it twice.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:32:20 -07:00
Jiri Slaby
c7d7abff40 serial: core, move termios handling to uart_startup
We should not fiddle with speed and cflags in .dtr_rts hook. Actually
we might not have tty at that moment already.

So move the console cflag copy and speed setup into uart_startup.
Actually the speed setup is already there, but we need to call it
unconditionally (uart_startup is called from uart_open with hw_init =
0).

This means we move uart_change_speed before dtr/rts setup in .dtr_rts.
But this should not matter as the setup should be called after
uart_change_speed anyway.
Before:                             After:
dtr/rts setup (dtr_rts)             uart_change_speed (startup)
uart_change_speed (update_termios)  dtr/rts setup (dtr_rts)
dtr/rts setup (update_termios)      dtr/rts setup (update_termios)

The second setup will dismiss with the next patch.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 16:32:20 -07:00
Jiri Slaby
4fd53ef5c9 TTY: serial_core, remove unused variable
drivers/tty/serial/serial_core.c:1980:2: warning: Value stored to 'tty' is never read
        tty = port->tty;
        ^     ~~~~~~~~~

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-19 14:41:47 -07:00
Alan Cox
6caa76b778 tty: now phase out the ioctl file pointer for good
Only oddities here are a couple of drivers that bogusly called the ldisc
helpers instead of returning -ENOIOCTLCMD. Fix the bug and the rest goes
away.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17 11:59:56 -08:00
Alan Cox
20b9d17715 tiocmset: kill the file pointer argument
Doing tiocmget was such fun we should do tiocmset as well for the same
reasons

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17 11:52:43 -08:00
Alan Cox
60b33c133c tiocmget: kill off the passing of the struct file
We don't actually need this and it causes problems for internal use of
this functionality. Currently there is a single use of the FILE * pointer.
That is the serial core which uses it to check tty_hung_up_p. However if
that is true then IO_ERROR is also already set so the check may be removed.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-17 11:47:33 -08:00
Yin Kangkai
5933a161ab serial-core: reset the console speed on resume
On some platforms, we need to restore the console speed on resume even
it was not suspended (no_console_suspend), and on others we don't have
to do that.

So don't care about the "console_suspend_enabled" and unconditionally
reset the console speed if it is a console.

This is actually a redo of ba15ab0 (Set proper console speed on resume
if console suspend is disabled) from Deepak Saxena.  I also tried to
investigate more to find out if this change will break others, here is
what I've found out:

commit 891b9dd107
Author: Jason Wang <jason77.wang@gmail.com>
    serial-core: restore termios settings when resume console ports

commit ca2e71aa8c
Author: Jason Wang <jason77.wang@gmail.com>
    serial-core: skip call set_termios/console_start when no_console_suspend

commit 4547be7809
Author: Stanislav Brabec <sbrabec@suse.cz>
    serial-core: resume serial hardware with no_console_suspend

commit ba15ab0e8d
Author: Deepak Saxena <dsaxena@laptop.org>
    Set proper console speed on resume if console suspend is disabled

from ba15ab0, we learned that, even if the console suspend is disabled
(when no_console_suspend is set), we may still need to "reset the port
to the state it was in before we suspended."

Then with 4547be7, this piece of code is removed.

And then Jason Wang added that back in ca2e71a and 891b9dd, to fix
some breakage on OMAP3EVM platform. From ca2e71a we learned that the
"set_termios" things is actually needed by both console is suspended
and not suspended.

That's why I removed the console_suspended_enabled condition, and only
call console_start() when we actually suspeneded it.

I also noticed in this thread:
http://marc.info/?t=129079257100004&r=1&w=2, which talked about on
some platforms, UART HW will be cut power whether or not we set
no_console_suspend, and then on resume it does not work quite well. I
have a similar HW, and this patch fixed this issue, don't know if this
patch also works on their platforms.

[Update: Stanislav tested this patch on Zaurus and reported it improves the
situation. Thanks.]

CC: Greg KH <greg@kroah.com>
CC: Deepak Saxena <dsaxena@laptop.org>
CC: Jason Wang <jason77.wang@gmail.com>
CC: Stanislav Brabec <sbrabec@suse.cz>
CC: Daniel Drake <dsd@laptop.org>
Signed-off-by: Yin Kangkai <kangkai.yin@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-02-03 14:14:00 -08:00
Greg Kroah-Hartman
ab4382d274 tty: move drivers/serial/ to drivers/tty/serial/
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: Greg Kroah-Hartman <gregkh@suse.de>
2011-01-13 12:10:18 -08:00