Commit Graph

535 Commits

Author SHA1 Message Date
Linus Torvalds f4f9c1ac78 Merge tag 'tty-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty and serial fixes from Greg KH:
 "Here are some tty and serial fixes for 3.4-rc2.

  Most important here is the pl011 fix, which has been reported by about
  100 different people, which means more people use it than I expected
  :)

  There are also some 8250 driver reverts due to some problems reported
  by them.  And other minor fixes as well.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

* tag 'tty-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  pch_uart: Add Kontron COMe-mTT10 uart clock quirk
  pch_uart: Fix MSI setting issue
  serial/8250_pci: add a "force background timer" flag and use it for the "kt" serial port
  Revert "serial/8250_pci: setup-quirk workaround for the kt serial controller"
  Revert "serial/8250_pci: init-quirk msi support for kt serial controller"
  tty/serial/omap: console can only be built-in
  serial: samsung: fix omission initialize ulcon in reset port fn()
  printk(): add KERN_CONT where needed in hpet and vt code
  tty/serial: atmel_serial: fix RS485 half-duplex problem
  tty: serial: altera_uart: Check for NULL platform_data in probe.
  isdn/gigaset: use gig_dbg() for debugging output
  omap-serial: Fix the error handling in the omap_serial probe
  serial: PL011: move interrupt clearing
2012-04-12 15:36:33 -07:00
Michael Brunner 11bbd5b6da pch_uart: Add Kontron COMe-mTT10 uart clock quirk
Add UART clock quirk for the Kontron COMe-mTT10 module.

The board has previously been called nanoETXexpress-TT, therefore this
is also checked.

As suggested by Darren Hart the comparison in this patch version is
placed after the FRI2 checks to ensure it will also work with possible
upcoming changes to the FRI2 firmware.

This patch follows the patchset submitted by Darren Hart at
commit a46f5533ec.

Signed-off-by: Michael Brunner <mibru@gmx.de>
Acked-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:58:41 -07:00
Tomoya MORINAGA 867c902e07 pch_uart: Fix MSI setting issue
The following patch (MSI setting) is not enough.

commit e463595fd9
Author: Alexander Stein <alexander.stein@systec-electronic.com>
Date:   Mon Jul 4 08:58:31 2011 +0200

    pch_uart: Add MSI support

    Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

To enable MSI mode, PCI bus-mastering must be enabled.
This patch enables the setting.

cc: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Tomoya MORINAGA <tomoya.rohm@gmail.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:43:26 -07:00
Dan Williams bc02d15a34 serial/8250_pci: add a "force background timer" flag and use it for the "kt" serial port
Workaround dropped notifications in the iir register.  Register reads
coincident with new interrupt notifications sometimes result in this
device clearing the interrupt event without reporting it in the read
data.

The serial core already has a heuristic for determining when a device
has an untrustworthy iir register.  In this case when we apriori know
that the iir is faulty use a flag (UPF_BUG_THRE) to bypass the test and
force usage of the background timer.

[stable: 3.3.x]
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Reported-by: Nhan H Mai <nhan.h.mai@intel.com>
Reported-by: Sudhakar Mamillapalli <sudhakar@fb.com>
Tested-by: Nhan H Mai <nhan.h.mai@intel.com>
Tested-by: Sudhakar Mamillapalli <sudhakar@fb.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:38:30 -07:00
Dan Williams 49b532f96f Revert "serial/8250_pci: setup-quirk workaround for the kt serial controller"
This reverts commit 448ac154c9.

The semantic of UPF_IIR_ONCE is only guaranteed to workaround the race
condition in the kt serial's iir register if the only source of
interrupts is THRE (fifo-empty) events.  An modem status event at the
wrong time can again cause an iir read to drop the 'empty' status
leading to a hang.  So, revert this in preparation for using the
existing "I don't trust my iir register" workaround in the 8250 core
(UART_BUG_THRE).

[stable: 3.3.x]
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: Sudhakar Mamillapalli <sudhakar@fb.com>
Reported-by: Nhan H Mai <nhan.h.mai@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:34:52 -07:00
Dan Williams 3579812373 Revert "serial/8250_pci: init-quirk msi support for kt serial controller"
This reverts commit e86ff4a63c.

This tried to enforce the semantics of one interrupt per iir read of the
THRE (transmit-hold empty) status, but events from other sources
(particularly modem status) defeat this guarantee.

This change also broke 8250_pci suspend/resume support as
pciserial_resume_ports() re-runs .init() quirks, but does not run
.exit() quirks in pciserial_suspend_ports() leading to reports like:

  sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:16.3/msi_irqs'

...and a subsequent crash.  The mismatch of init/exit at suspend/resume
seems like a bug in its own right.

[stable: 3.3.x]
Cc: stable <stable@vger.kernel.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: Sudhakar Mamillapalli <sudhakar@fb.com>
Reported-by: Nhan H Mai <nhan.h.mai@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:34:16 -07:00
Arnd Bergmann d8c4019b41 tty/serial/omap: console can only be built-in
When the omap serial driver is built as a module, we must
not allow the console driver to be selected, because consoles
can not be loadable modules.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Acked-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:34:16 -07:00
Kukjin Kim 7b246a1d0d serial: samsung: fix omission initialize ulcon in reset port fn()
Fix omission initialize ulcon in s3c24xx_serial_resetport(),
reset port function in drivers/tty/serial/samsung.c. It has
been happened from commit 0dfb3b41("serial: samsung: merge
all SoC specific port reset functions")

Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Cc: stable <stable@vger.kernel.org> [3.3]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:30:39 -07:00
Siftar, Gabe 57c3686842 tty/serial: atmel_serial: fix RS485 half-duplex problem
On our custom board, we are using RS485 in half-duplex mode on an AT91SAM9G45.
SER_RS485_RX_DURING_TX is not set as we do not want to receive the data we
transmit (our transceiver will receive transmitted data).
Although the current driver attempts to disable and enable the receiver at the
appropriate points, incoming data is still loaded into the receive register
causing our code to receive the very last byte that was sent once the receiver
is enabled.

I ran this by Atmel support and they wrote: "The issue comes from the fact
that you disable the PDC/DMA Reception and not the USART Reception channel. In
your case, the[n] you will still receive data into the USART_RHR register, and
maybe you [h]ave the overrun flag set. So please disable the USART reception
channel."

The following patch should force the driver to enable/disable the receiver via
RXEN/RXDIS fields of the USART control register. It fixed the issue I was
having.

Signed-off-by: Gabe Siftar <gabe.siftar@getingeusa.com>
[nicolas.ferre@atmel.com: slightly modify commit message]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:30:39 -07:00
Yuriy Kozlov acede70d65 tty: serial: altera_uart: Check for NULL platform_data in probe.
Follow altera_jtag_uart.  This fixes a crash if there is a mistake in the DTS.

Signed-off-by: Yuriy Kozlov <ykozlov@ptcusa.com>
Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:30:39 -07:00
Shubhrajyoti D 388bc26226 omap-serial: Fix the error handling in the omap_serial probe
The patch does the following

- The pm_runtime_disable is called in the remove not in the error
  case of probe.The patch calls the pm_runtime_disable in the error
  case.
- Calls pm_runtime_put in the error case.
- The  up is not freed in the error path. Fix the memory leak by using
  devm_* so that the memory need not be freed in the driver.
- Also the iounmap is not called fix the same by calling using devm_ioremap.
- Make the name of the error tags more meaningful.

Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>
Cc: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Shubhrajyoti D <shubhrajyoti@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-09 10:30:38 -07:00
Linus Torvalds 664481ed45 Merge tag 'sh-for-linus' of git://github.com/pmundt/linux-sh
Pull SuperH fixes from Paul Mundt.

* tag 'sh-for-linus' of git://github.com/pmundt/linux-sh:
  sh: fix clock-sh7757 for the latest sh_mobile_sdhi driver
  serial: sh-sci: use serial_port_in/out vs sci_in/out.
  sh: vsyscall: Fix up .eh_frame generation.
  sh: dma: Fix up device attribute mismatch from sysdev fallout.
  sh: dwarf unwinder depends on SHcompact.
  sh: fix up fallout from system.h disintegration.
2012-04-07 09:52:46 -07:00
Linus Walleij c3d8b76f61 serial: PL011: move interrupt clearing
Commit 360f748b204275229f8398cb2f9f53955db1503b
"serial: PL011: clear pending interrupts"
attempts to clear interrupts by writing to a
yet-unassigned memory address. This fixes the issue.

The breaking patch is marked for stable so should be
carried along with the other patch.

Cc: Shreshtha Kumar Sahu <shreshthakumar.sahu@stericsson.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: stable <stable@vger.kernel.org>
Cc: Nicolas Pitre <nico@fluxnic.net>
Reported-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-04-06 14:04:33 -07:00
Linus Torvalds 5d32c88f0b Merge branch 'akpm' (Andrew's patch-bomb)
Merge batch of fixes from Andrew Morton:
 "The simple_open() cleanup was held back while I wanted for laggards to
  merge things.

  I still need to send a few checkpoint/restore patches.  I've been
  wobbly about merging them because I'm wobbly about the overall
  prospects for success of the project.  But after speaking with Pavel
  at the LSF conference, it sounds like they're further toward
  completion than I feared - apparently davem is at the "has stopped
  complaining" stage regarding the net changes.  So I need to go back
  and re-review those patchs and their (lengthy) discussion."

* emailed from Andrew Morton <akpm@linux-foundation.org>: (16 patches)
  memcg swap: use mem_cgroup_uncharge_swap fix
  backlight: add driver for DA9052/53 PMIC v1
  C6X: use set_current_blocked() and block_sigmask()
  MAINTAINERS: add entry for sparse checker
  MAINTAINERS: fix REMOTEPROC F: typo
  alpha: use set_current_blocked() and block_sigmask()
  simple_open: automatically convert to simple_open()
  scripts/coccinelle/api/simple_open.cocci: semantic patch for simple_open()
  libfs: add simple_open()
  hugetlbfs: remove unregister_filesystem() when initializing module
  drivers/rtc/rtc-88pm860x.c: fix rtc irq enable callback
  fs/xattr.c:setxattr(): improve handling of allocation failures
  fs/xattr.c:listxattr(): fall back to vmalloc() if kmalloc() failed
  fs/xattr.c: suppress page allocation failure warnings from sys_listxattr()
  sysrq: use SEND_SIG_FORCED instead of force_sig()
  proc: fix mount -t proc -o AAA
2012-04-05 15:30:34 -07:00
Stephen Boyd 234e340582 simple_open: automatically convert to simple_open()
Many users of debugfs copy the implementation of default_open() when
they want to support a custom read/write function op.  This leads to a
proliferation of the default_open() implementation across the entire
tree.

Now that the common implementation has been consolidated into libfs we
can replace all the users of this function with simple_open().

This replacement was done with the following semantic patch:

<smpl>
@ open @
identifier open_f != simple_open;
identifier i, f;
@@
-int open_f(struct inode *i, struct file *f)
-{
(
-if (i->i_private)
-f->private_data = i->i_private;
|
-f->private_data = i->i_private;
)
-return 0;
-}

@ has_open depends on open @
identifier fops;
identifier open.open_f;
@@
struct file_operations fops = {
...
-.open = open_f,
+.open = simple_open,
...
};
</smpl>

[akpm@linux-foundation.org: checkpatch fixes]
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-04-05 15:25:50 -07:00
Sam Ravnborg ca6f327dfd serial/sunzilog: fix keyboard on SUN SPARCstation
The keyboard on my SUN SPARCstation 5 no longer worked.

    The culprint was: d4e33fac24
    ("serial: Kill off NO_IRQ")

Fix up logic for no irq / irq so the keyboard works again.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2012-04-04 00:37:10 -07:00
Paul Mundt b12bb29f84 serial: sh-sci: use serial_port_in/out vs sci_in/out.
Follows the 8250 change for pretty much the same rationale.

See commit "serial: use serial_port_in/out vs serial_in/out in 8250".

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2012-03-30 19:50:15 +09:00
Linus Torvalds f52b69f86e Merge tag 'sh-for-linus' of git://github.com/pmundt/linux-sh
Pull SuperH updates from Paul Mundt.

* tag 'sh-for-linus' of git://github.com/pmundt/linux-sh: (25 commits)
  sh: Support I/O space swapping where needed.
  sh: use set_current_blocked() and block_sigmask()
  sh: no need to reset handler if SA_ONESHOT
  sh: intc: Fix up section mismatch for intc_ack_data
  sh: select ARCH_DISCARD_MEMBLOCK.
  sh: Consolidate duplicate _32/_64 unistd definitions.
  sh: ecovec: switch SDHI controllers to card polling
  sh: Avoid exporting unimplemented syscalls.
  sh: add platform_device for RSPI in setup-sh7757
  SH: pci-sh7780: enable big-endian operation.
  serial: sh-sci: fix a race of DMA submit_tx on transfer
  sh: dma: Collect up CHCR of SH7763, SH7764, SH7780 and SH7785
  sh: dma: Collect up CHCR of SH7723 and SH7730
  sh/next: Fix build fail by asm/system.h in asm/bitops.h
  arch/sh/drivers/dma/{dma-g2,dmabrg}.c: ensure arguments to request_irq and free_irq are compatible
  sh: cpufreq: Wire up scaling_available_freqs support.
  sh: cpufreq: notify about rate rounding fallback.
  sh: cpufreq: Support CPU clock frequency table.
  sh: cpufreq: struct device lookup from CPU topology.
  sh: cpufreq: percpu struct clk accounting.
  ...
2012-03-30 00:09:17 -07:00
Linus Torvalds ef08e78268 Merge branch 'next' of git://git.infradead.org/users/vkoul/slave-dma
Pull slave-dmaengine update from Vinod Koul:
 "This includes the cookie cleanup by Russell, the addition of context
  parameter for dmaengine APIs, more arm dmaengine driver cleanup by
  moving code to dmaengine, this time for imx by Javier and pl330 by
  Boojin along with the usual driver fixes."

Fix up some fairly trivial conflicts with various other cleanups.

* 'next' of git://git.infradead.org/users/vkoul/slave-dma: (67 commits)
  dmaengine: imx: fix the build failure on x86_64
  dmaengine: i.MX: Fix merge of cookie branch.
  dmaengine: i.MX: Add support for interleaved transfers.
  dmaengine: imx-dma: use 'dev_dbg' and 'dev_warn' for messages.
  dmaengine: imx-dma: remove 'imx_dmav1_baseaddr' and 'dma_clk'.
  dmaengine: imx-dma: remove unused arg of imxdma_sg_next.
  dmaengine: imx-dma: remove internal structure.
  dmaengine: imx-dma: remove 'resbytes' field of 'internal' structure.
  dmaengine: imx-dma: remove 'in_use' field of 'internal' structure.
  dmaengine: imx-dma: remove sg member from internal structure.
  dmaengine: imx-dma: remove 'imxdma_setup_sg_hw' function.
  dmaengine: imx-dma: remove 'imxdma_config_channel_hw' function.
  dmaengine: imx-dma: remove 'imxdma_setup_mem2mem_hw' function.
  dmaengine: imx-dma: remove dma_mode member of internal structure.
  dmaengine: imx-dma: remove data member from internal structure.
  dmaengine: imx-dma: merge old dma-v1.c with imx-dma.c
  dmaengine: at_hdmac: add slave config operation
  dmaengine: add context parameter to prep_slave_sg and prep_dma_cyclic
  dmaengine/dma_slave: introduce inline wrappers
  dma: imx-sdma: Treat firmware messages as warnings instead of erros
  ...
2012-03-29 15:34:57 -07:00
Linus Torvalds 0195c00244 Merge tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system
Pull "Disintegrate and delete asm/system.h" from David Howells:
 "Here are a bunch of patches to disintegrate asm/system.h into a set of
  separate bits to relieve the problem of circular inclusion
  dependencies.

  I've built all the working defconfigs from all the arches that I can
  and made sure that they don't break.

  The reason for these patches is that I recently encountered a circular
  dependency problem that came about when I produced some patches to
  optimise get_order() by rewriting it to use ilog2().

  This uses bitops - and on the SH arch asm/bitops.h drags in
  asm-generic/get_order.h by a circuituous route involving asm/system.h.

  The main difficulty seems to be asm/system.h.  It holds a number of
  low level bits with no/few dependencies that are commonly used (eg.
  memory barriers) and a number of bits with more dependencies that
  aren't used in many places (eg.  switch_to()).

  These patches break asm/system.h up into the following core pieces:

    (1) asm/barrier.h

        Move memory barriers here.  This already done for MIPS and Alpha.

    (2) asm/switch_to.h

        Move switch_to() and related stuff here.

    (3) asm/exec.h

        Move arch_align_stack() here.  Other process execution related bits
        could perhaps go here from asm/processor.h.

    (4) asm/cmpxchg.h

        Move xchg() and cmpxchg() here as they're full word atomic ops and
        frequently used by atomic_xchg() and atomic_cmpxchg().

    (5) asm/bug.h

        Move die() and related bits.

    (6) asm/auxvec.h

        Move AT_VECTOR_SIZE_ARCH here.

  Other arch headers are created as needed on a per-arch basis."

Fixed up some conflicts from other header file cleanups and moving code
around that has happened in the meantime, so David's testing is somewhat
weakened by that.  We'll find out anything that got broken and fix it..

* tag 'split-asm_system_h-for-linus-20120328' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-asm_system: (38 commits)
  Delete all instances of asm/system.h
  Remove all #inclusions of asm/system.h
  Add #includes needed to permit the removal of asm/system.h
  Move all declarations of free_initmem() to linux/mm.h
  Disintegrate asm/system.h for OpenRISC
  Split arch_align_stack() out from asm-generic/system.h
  Split the switch_to() wrapper out of asm-generic/system.h
  Move the asm-generic/system.h xchg() implementation to asm-generic/cmpxchg.h
  Create asm-generic/barrier.h
  Make asm-generic/cmpxchg.h #include asm-generic/cmpxchg-local.h
  Disintegrate asm/system.h for Xtensa
  Disintegrate asm/system.h for Unicore32 [based on ver #3, changed by gxt]
  Disintegrate asm/system.h for Tile
  Disintegrate asm/system.h for Sparc
  Disintegrate asm/system.h for SH
  Disintegrate asm/system.h for Score
  Disintegrate asm/system.h for S390
  Disintegrate asm/system.h for PowerPC
  Disintegrate asm/system.h for PA-RISC
  Disintegrate asm/system.h for MN10300
  ...
2012-03-28 15:58:21 -07:00
David Howells 9ffc93f203 Remove all #inclusions of asm/system.h
Remove all #inclusions of asm/system.h preparatory to splitting and killing
it.  Performed with the following command:

perl -p -i -e 's!^#\s*include\s*<asm/system[.]h>.*\n!!' `grep -Irl '^#\s*include\s*<asm/system[.]h>' *`

Signed-off-by: David Howells <dhowells@redhat.com>
2012-03-28 18:30:03 +01:00
David Howells d550bbd40c Disintegrate asm/system.h for Sparc
Disintegrate asm/system.h for Sparc.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: sparclinux@vger.kernel.org
2012-03-28 18:30:03 +01:00
David Howells b1a154dbf9 Disintegrate asm/system.h for CRIS
Disintegrate asm/system.h for CRIS.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
cc: linux-cris-kernel@axis.com
2012-03-28 18:30:02 +01:00
David Howells 9f97da78bf Disintegrate asm/system.h for ARM
Disintegrate asm/system.h for ARM.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Russell King <linux@arm.linux.org.uk>
cc: linux-arm-kernel@lists.infradead.org
2012-03-28 18:30:01 +01:00
Yoshii Takashi 49d4bcaddc serial: sh-sci: fix a race of DMA submit_tx on transfer
When DMA is enabled, sh-sci transfer begins with
 uart_start()
  sci_start_tx()
    if (cookie_tx < 0) schedule_work()
Then, starts DMA when wq scheduled, -- (A)
 process_one_work()
  work_fn_rx()
   cookie_tx = desc->submit_tx()
And finishes when DMA transfer ends, -- (B)
 sci_dma_tx_complete()
  async_tx_ack()
  cookie_tx = -EINVAL
  (possible another schedule_work())

This A to B sequence is not reentrant, since controlling variables
(for example, cookie_tx above) are not queues nor lists. So, they
must be invoked as A B A B..., otherwise results in kernel crash.

To ensure the sequence, sci_start_tx() seems to test if cookie_tx < 0
(represents "not used") to call schedule_work().
But cookie_tx will not be set (to a cookie, also means "used") until
in the middle of work queue scheduled function work_fn_tx().

This gap between the test and set allows the breakage of the sequence
under the very frequently call of uart_start().
Another gap between async_tx_ack() and another schedule_work() results
in the same issue, too.

This patch introduces a new condition "cookie_tx == 0" just to mark
it is "busy" and assign it within spin-locked region to fill the gaps.

Signed-off-by: Takashi Yoshii <takashi.yoshii.zj@renesas.com>
Reviewed-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
2012-03-28 14:26:05 +09:00