Prepare for replacing read_cnt field with computed value.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

N_TTY .chars_in_buffer() method requires serialized access if
the current thread is not the single-consumer, n_tty_read().

Separate the internal interface; prepare for lockless read-side.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Instead of pushing one char per loop, pre-compute the data length
to copy and copy all at once.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Simplify n_tty_read(); extract complex copy algorithm
into separate function, canon_copy_to_user().
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Although line discipline receiving is single-producer/single-consumer,
using tty->receive_room to manage flow control creates unnecessary
critical regions requiring additional lock use.

Instead, introduce the optional .receive_buf2() ldisc method which
returns the # of bytes actually received. Serialization is guaranteed
by the caller.

In turn, the line discipline should schedule the buffer work item
whenever space becomes available; ie., when there is room to receive
data and receive_room() previously returned 0 (the buffer work
item stops processing if receive_buf2() returns 0). Note the
'no room' state need not be atomic despite concurrent use by two
threads because only the buffer work thread can set the state and
only the read() thread can clear the state.

Add n_tty_receive_buf2() as the receive_buf2() method for N_TTY.
Provide a public helper function, tty_ldisc_receive_buf(), to use
when directly accessing the receive_buf() methods.

Line disciplines not using input flow control can continue to set
tty->receive_room to a fixed value and only provide the receive_buf()
method.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Ldisc interface functions must be called with interrupts enabled.
Separating the ldisc calls into a helper function simplies the
eventual removal of the spinlock.

Note that access to the buf->head ptr outside the spinlock is
safe here because;
* __tty_buffer_flush() is prevented from running while buffer work
  performs i/o,
* tty_buffer_find() only assigns buf->head if the flip buffer list
  is empty (which is never the case in flush_to_ldisc() since at
  least one buffer is always left in the list after use)
Access to the read index outside the spinlock is safe here for the
same reasons.

Update the buffer's read index _after_ the data has been received
by the ldisc.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

tty_set_ldisc() is guaranteed exclusive use of the line discipline
by tty_ldisc_lock_pair_timeout(); shutting off input by resetting
receive_room is unnecessary.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

The hangup may already have happened; check for that state also.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Rename o_ldisc to avoid confusion with the ldisc of the
'other' tty.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Line discipline locking was performed with a combination of
a mutex, a status bit, a count, and a waitqueue -- basically,
a rw semaphore.

Replace the existing combination with an ld_semaphore.

Fixes:
 1) the 'reference acquire after ldisc locked' bug
 2) the over-complicated halt mechanism
 3) lock order wrt. tty_lock()
 4) dropping locks while changing ldisc
 5) previously unidentified deadlock while locking ldisc from
    both linked ttys concurrently
 6) previously unidentified recursive deadlocks

Adds much-needed lockdep diagnostics.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Just as the tty pair must be locked in a stable sequence
(ie, independent of which is consider the 'other' tty), so must
the ldisc pair be locked in a stable sequence as well.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The file scope spinlock identifier, tty_ldisc_lock, will collide
with the file scope lock function tty_ldisc_lock() so rename it.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A few differences needed by OCTEON:

o These are DWC UARTS, but have USR at a different offset.

o Internal SoC buses require reading back from registers to maintain
  write ordering.

o 8250 on OCTEON appears with 64-bit wide registers, so when using
  readb/writeb in big endian mode we have to adjust the membase to hit
  the proper part of the register.

o No UCV register, so we hard code some properties.

Because OCTEON doesn't have a UCV register, I change where
dw8250_setup_port(), which reads the UCV, is called by pushing it in
to the OF and ACPI probe functions, and move unchanged
dw8250_setup_port() earlier in the file.
Signed-off-by: NDavid Daney <david.daney@cavium.com>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: linux-mips@linux-mips.org
Cc: Jamie Iles <jamie@jamieiles.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-serial@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/5516/Acked-by: NArnd Bergmann <arnd@arndb.de>
Reviewed-by: NHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: NRalf Baechle <ralf@linux-mips.org>

Revert "serial: 8250_pci: add support for another kind of NetMos Technology PCI 9835 Multi-I/O Controller"

This reverts commit 8d2f8cd4.

As reported by Stefan, this device already works with the parport_serial
driver, so the 8250_pci driver should not also try to grab it as well.
Reported-by: NStefan Seyfried <stefan.seyfried@googlemail.com>
Cc: Wang YanQing <udknight@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This change addresses two warnings that are flagged by gcc relating to
potential access to the ssr and cks variables while they are uninitialised.

I have addressed this by initialising the values to
the defaults present in sci_baud_calc_hscif().

It is my analysis that cks is always initialised if used
but that without this change ssr may be accessed while uninitialised.

The code altered by this patch was introduced by commit
f303b364 ("serial: sh-sci: HSCIF support").
Reported-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

Use DMI_BOARD_NAME to determine if we are running on a MinnowBoard and
set the uart clock to 50MHz if so. This removes the need to pass the
user_uartclk to the kernel at boot time.
Signed-off-by: NDarren Hart <dvhart@linux.intel.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Peter Waskiewicz <peter.p.waskiewicz.jr@intel.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Replace clk_enable/disable with clk_prepare_enable/disable_unprepare to
avoid common clk framework warnings.
Signed-off-by: NBoris BREZILLON <b.brezillon@overkiz.com>
Acked-by: NNicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Clocks are not clk_put() in this driver's error paths during
probe. The code that checks for clock errors also fails to
properly return the error code from the pclk member if it turns
out to be the failing clock, leading to potentially confusing
error values if the clk member is not an error pointer. Fix these
problems with devm_clk_get() and proper error checking.

Removing the clk_put() in msm_serial_remove() also points out
that msm_port is unused. Furthermore, msm_port is the wrong type
and so the clk_put() would be using the wrong pointer. Replace it
with the proper type and call uart_remove_one_port() to do the
proper cleanup.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NDavid Brown <davidb@codeaurora.org>

Add calls to clk_prepare and unprepare so that MSM can migrate to
the common clock framework.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NStephen Boyd <sboyd@codeaurora.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NDavid Brown <davidb@codeaurora.org>

I got a build error today that made me realize that it is not
possible to build a kernel for a SiRF platform without enabling
CONFIG_PRIMA2, since a lot of common code depends on CONFIG_PRIMA2.

This fixes all occurences that appear like common SiRF code.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NMark Brown <broonie@linaro.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: NBarry Song <Baohua.Song@csr.com>
Acked-by: NMike Turquette <mturquette@linaro.org>

All EXYNOS4/5 SoCs share a common driver data in the samsung serial
driver. Hence, let the driver data inclusion be based on ARCH_EXYNOS
instead of SOC specific definition.
Signed-off-by: NChander Kashyap <chander.kashyap@linaro.org>
Reviewed-by: NTomasz Figa <t.figa@samsung.com>
Reviewed by: Girish K S <ks.giri@samsung.com>
Signed-off-by: NKukjin Kim <kgene.kim@samsung.com>

The C8000 workstation (64 bit kernel only) has a somewhat different
serial port configuration than other models.
Thomas Bogendoerfer sent a patch to fix this in September 2010, which
was now minimally modified by me.
Signed-off-by: NThomas Bogendoerfer <tsbogend@alpha.franken.de>
Signed-off-by: NHelge Deller <deller@gmx.de>

Commit 19ffd68f
('pty: Remove redundant itty reset') introduced a regression
whereby the other pty's linkage is not cleared on teardown.
This triggers a false positive diagnostic in testing.

Properly reset the itty linkage.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Cc: stable <stable@vger.kernel.org> # 3.10
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Although the driver-side input path must update the available
buffer space, it should not reschedule itself. If space is still
available and the flip buffers are not empty, flush_to_ldisc()
will loop again.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

receive_room is used to control the amount of data the flip
buffer work can push to the read buffer. This update is unsafe:

  CPU 0                        |  CPU 1
                               |
                               | n_tty_read()
                               |   n_tty_set_room()
                               |     left = <calc of space>
n_tty_receive_buf()            |
  <push data to buffer>        |
  n_tty_set_room()             |
    left = <calc of space>     |
    tty->receive_room = left   |
                               |     tty->receive_room = left

receive_room is now updated with a stale calculation of the
available buffer space, and the subsequent work loop will likely
overwrite unread data in the input buffer.

Update receive_room atomically with the calculation of the
available buffer space.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

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

minimum_to_wake is unique to N_TTY processing, and belongs in
per-ldisc data.

Add the ldisc method, ldisc_ops::fasync(), to notify line disciplines
when signal-driven I/O is enabled or disabled. When enabled for N_TTY
(by fcntl(F_SETFL, O_ASYNC)), blocking reader/polls will be woken
for any readable input. When disabled, blocking reader/polls are not
woken until the read buffer is full.

Canonical mode (L_ICANON(tty), n_tty_data::icanon) is not affected by
the minimum_to_wake setting.
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

In the runtime_suspend function pdata is not being used, and
also blocks the function in device tree based booting. Fix it
by removing the unused pdata from the runtime_suspend function.

Further, context loss count is not being passed in pdata, so
let's just reinitialize the port every time for those case.
This can be further optimized later on for the device tree
case by adding detection for the hardware state and possibly
by adding a driver specific autosuspend timeout.

And doing this, we can then make the related dev_err into a
dev_dbg message instead of an error.

In order for the wake-up events to work, we also need to set
autosuspend_timeout to -1 if 0, and also device_init_wakeup()
as that's not being done by the platform init code for the
device tree case.

Note that this does not affect legacy booting, and in fact
might make it work for the cases where the context loss info
is not being passed in pdata.

Thanks to Kevin Hilman <khilman@linaro.org> for debugging
and suggesting fixes for the autosuspend_timeout and
device_init_wakeup() related initializiation.
Reviewed-by: NKevin Hilman <khilman@linaro.org>
Tested-by: NKevin Hilman <khilman@linaro.org>
Signed-off-by: NTony Lindgren <tony@atomide.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since commit 0c375501 (serial: imx: enable the clocks for console), the
imx_startup() function calls clk_prepare_enable conditionally, so we
need to call clk_disable_unprepare inside imx_shutdown() under the same
condition to avoid unbalanced clock calls.

This avoids the following warning:

------------[ cut here ]------------
WARNING: CPU: 0 PID: 70 at drivers/clk/clk.c:780 __clk_disable+0x68/0x84()
Modules linked in:
CPU: 0 PID: 70 Comm: mountall Not tainted 3.10.0-rc4-next-20130607+ #435
Backtrace:
[<800116a4>] (dump_backtrace+0x0/0x10c) from [<80011844>] (show_stack+0x18/0x1c)
 r6:8069f4e8 r5:0000030c r4:00000000 r3:00000000
[<8001182c>] (show_stack+0x0/0x1c) from [<8053bce0>] (dump_stack+0x78/0x94)
[<8053bc68>] (dump_stack+0x0/0x94) from [<80023df8>] (warn_slowpath_common+0x6c/0x8c)
 r4:00000000 r3:00000000
[<80023d8c>] (warn_slowpath_common+0x0/0x8c) from [<80023e3c>] (warn_slowpath_null+0x24/0x2c)
 r8:bf2ed008 r7:bfaa9810 r6:000f0013 r5:bf824b80 r4:bf824b80
[<80023e18>] (warn_slowpath_null+0x0/0x2c) from [<8041af84>] (__clk_disable+0x68/0x84)
[<8041af1c>] (__clk_disable+0x0/0x84) from [<8041b098>] (clk_disable+0x20/0x2c)
 r4:600f0013 r3:00000001
[<8041b078>] (clk_disable+0x0/0x2c) from [<802c93e8>] (imx_shutdown+0xbc/0xec)
 r5:bf824b80 r4:bfaa9810
[<802c932c>] (imx_shutdown+0x0/0xec) from [<802c63a0>] (uart_port_shutdown+0x34/0x40)
 r5:bf86f860 r4:bfaa9810
[<802c636c>] (uart_port_shutdown+0x0/0x40) from [<802c68c0>] (uart_shutdown+0x98/0xc4)
 r4:bf86f800 r3:00000000
[<802c6828>] (uart_shutdown+0x0/0xc4) from [<802c7514>] (uart_close+0x5c/0x198)
 r7:bfaa9810 r6:bf274400 r5:bf86f86c r4:bf86f800
[<802c74b8>] (uart_close+0x0/0x198) from [<802ac648>] (tty_release+0xf8/0x500)
[<802ac550>] (tty_release+0x0/0x500) from [<800c5a30>] (__fput+0x9c/0x208)
[<800c5994>] (__fput+0x0/0x208) from [<800c5bac>] (____fput+0x10/0x14)
[<800c5b9c>] (____fput+0x0/0x14) from [<80040234>] (task_work_run+0xb4/0xec)
[<80040180>] (task_work_run+0x0/0xec) from [<80029238>] (do_exit+0x2b0/0x920)
 r8:8000e144 r7:000000f8 r6:bf306300 r5:00000000 r4:bfac1180
[<80028f88>] (do_exit+0x0/0x920) from [<80029a4c>] (do_group_exit+0x50/0xd4)
 r7:000000f8
[<800299fc>] (do_group_exit+0x0/0xd4) from [<80029ae8>] (__wake_up_parent+0x0/0x28)
 r7:000000f8 r6:00000001 r5:0006f7ae r4:0006f79a
[<80029ad0>] (SyS_exit_group+0x0/0x18) from [<8000dfc0>] (ret_fast_syscall+0x0/0x30)
---[ end trace 16d080eb7efea4e9 ]---
Reported-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Tested-by: NShawn Guo <shawn.guo@linaro.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This bug appear when a second PSC based driver appends an interrupt
routine to the FIFO controller shared interrupt (like spi-mpc512x-psc).
When reboot, uart_shutdown() remove the serial console interrupt handler
while spi-mpc512x-psc isr is still activate and cause the following kernel
panic:

The system is going down for reboot NOW!rpc (ttyPSC0) (Mon Jun 10 12:26:07 20
INIT: Sending processirq 40: nobody cared (try booting with the "irqpoll" option)
CPU: 0 PID: 0 Comm: swapper Not tainted 3.10.0-rc4-next-20130607-00001-ga0bceb3-dirty #5
Call Trace:
[cfff9f00] [c0007910] show_stack+0x48/0x150 (unreliable)
[cfff9f40] [c005ae60] __report_bad_irq.isra.6+0x34/0xe0
[cfff9f60] [c005b194] note_interrupt+0x214/0x26c
[cfff9f90] [c00590fc] handle_irq_event_percpu+0xd0/0x1bc
[cfff9fd0] [c005921c] handle_irq_event+0x34/0x54
[cfff9fe0] [c005b8f4] handle_level_irq+0x90/0xf4
[cfff9ff0] [c000cb98] call_handle_irq+0x18/0x28
[c050dd60] [c000575c] do_IRQ+0xcc/0x124
[c050dd90] [c000eb04] ret_from_except+0x0/0x14
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When using MFD HSU based console, sometime we need the sysrq function
to help debugging kernel. The sysrq code is basically there, this
patch just simply enable it.
Signed-off-by: NFeng Tang <feng.tang@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 69939035
('pty: Ignore slave pty close() if never successfully opened')
introduced a bug with ptys whereby a write() in parallel with an
open() on an existing pty could mistakenly indicate an I/O error.

Only indicate an I/O error if the condition on open() actually exists.
Reported-by: NMarkus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: NPeter Hurley <peter@hurleysoftware.com>
Tested-by: NMikael Pettersson <mikpe@it.uu.se>
Cc: stable <stable@vger.kernel.org> # 3.9
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Commit 421b40a6 ("tty/vt: Fix vc_deallocate() lock order") changed
the behavior when deallocating VT 1.  Previously if trying to
deallocate VT1 and it is busy, we would return EBUSY.  The commit
changed this to return 0 (success).

This commit restores the old behavior.
Signed-off-by: NRoss Lagerwall <rosslagerwall@gmail.com>
Tested-by: NMikael Pettersson <mikpe@it.uu.se>
Acked-by: NPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Adds support for "High Speed Serial Communications Interface with FIFO",
essentially a SCIF with 128-byte FIFOs and more accurate baud rate
generator.
Signed-off-by: NUlrich Hecht <ulrich.hecht@gmail.com>
Acked-by: NPaul Mundt <lethal@linux-sh.org>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

This augments the PL011 UART driver to utilize the new pinctrl
core PM helpers to transition the driver to default and sleep
states, cutting away some boilerplate code.

Cc: Hebbar Gururaja <gururaja.hebbar@ti.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: NWolfram Sang <wsa@the-dreams.de>
Acked-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

The console's clocks are disabled after the uart driver is probed.
It makes that we can see less log from the console now
(though we still can get all the log by the `dmesg`).

So enable the clocks for console, and we can see all the log again.

This patch also disables the sport->clk_per when we fail to enable
the sport->clk_ipg;
Signed-off-by: NHuang Shijie <b32955@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Add Freescale lpuart driver support. The lpuart device
can be found on Vybrid VF610 and Layerscape LS-1 SoCs.
Signed-off-by: NJingchang Lu <b35083@freescale.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>