Remove the global 'dclk' variable, instead replacing it with a
variable local to the dpllcore clock type C file. This removes some
of the special-case code surrounding the OMAP2xxx clock init.
This patch is a prerequisite for the removal of the
omap_prcm_restart() code from arch/arm/mach-omap2/prcm.c. It also
cleans up some special-case OMAP2xxx clock code in the process.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>
Add SoC reset functions into the PRM code. These functions are based
on code from mach-omap2/prcm.c. They reset the SoC using the CORE DPLL
reset method (as opposed to one of the other two or three chip reset
methods).
Adding them here will facilitate their removal from
arch/arm/mach-omap2/prcm.c. (prcm.c is deprecated.)
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>
Get rid of the mach-omap2/common.c globals by moving the global
initialization for IP block addresses that must occur early into
mach-omap2/io.c. In the process, remove the *_map_common_io*() and
SoC-specific *set_globals* functions.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>
omap_prcm_get_reset_sources() is now unused; so, remove it.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Tested-by: Vaibhav Hiremath <hvaibhav@ti.com>
Previously the OMAP watchdog driver used a non-standard way to report
the chip reset source via the GETBOOTSTATUS ioctl. This patch
converts the driver to use the standard WDIOF_* flags for this
purpose.
This patch may break existing userspace code that uses the existing
non-standard data format returned by the OMAP watchdog driver's
GETBOOTSTATUS ioctl. To fetch detailed reset source information,
userspace code will need to retrieve it directly from the CGRM or PRM
drivers when those are completed.
Previously, to fetch the reset source, the driver either read a
register outside the watchdog IP block (OMAP1), or called a function
exported directly from arch/arm/mach-omap2. Both approaches are
broken. This patch also converts the driver to use a platform_data
function pointer. This approach is temporary, and is due to the lack
of drivers for the OMAP16xx+ Clock Generation and Reset Management IP
block and the OMAP2+ Power and Reset Management IP block. Once
drivers are available for those IP blocks, the watchdog driver can be
converted to call exported functions from those drivers directly.
At that point, the platform_data function pointer can be removed.
In the short term, this patch is needed to allow the PRM code to be
removed from arch/arm/mach-omap2 (it is being moved to a driver).
This version integrates a fix from Jon Hunter <jon-hunter@ti.com>
that avoids a NULL pointer dereference in a DT-only boot, and integrates
a patch commit message fix from Felipe Balbi <balbi@ti.com>.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
[paul@pwsan.com: integrated pdata fix from Jon Hunter]
Cc: Jon Hunter <jon-hunter@ti.com>
[paul@pwsan.com: integrated changelog fix from Felipe Balbi]
Cc: Felipe Balbi <balbi@ti.com>
The OMAP watchdog timer driver directly calls a function exported by
code in arch/arm/mach-omap2. This is not good; it tightly couples
this driver to the mach-omap2 integration code. Instead, add a
temporary platform_data function pointer to abstract this function
call. A subsequent patch will convert the watchdog driver to use this
function pointer.
This patch also moves the device creation code out of
arch/arm/mach-omap2/devices.c and into arch/arm/mach-omap2/wd_timer.c.
This is another step towards the removal of
arch/arm/mach-omap2/devices.c.
Cc: Wim Van Sebroeck <wim@iguana.be>
Acked-by: Wim Van Sebroeck <wim@iguana.be>
[paul@pwsan.com: skip wd_timer device creation when DT blob is present]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
An older version of the patch "ARM: OMAP1: create read_reset_sources()
function (for initial use by watchdog)" was sent upstream, which used
the wrong return type for the omap1_get_reset_sources() function.
Fix it to return a u32, which is what the WDTIMER platform_data
function pointer read_reset_sources() expects.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
OMAP cleanup-headers branch. Intended for 3.8 cleanup.
Basic build, boot, and PM test logs are available from here:
http://www.pwsan.com/omap/testlogs/cleanup-headers-compile-fixes-3.8/20121026132711/
Due to underlying problems in v3.7-rc2, several tests fail. These
failures are unrelated to these patches.
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Merge tag 'omap-cleanup-fixes-a-for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into omap-for-v3.8/cleanup-headers
Several fixes for build failures and sparse warnings in the
OMAP cleanup-headers branch. Intended for 3.8 cleanup.
Basic build, boot, and PM test logs are available from here:
http://www.pwsan.com/omap/testlogs/cleanup-headers-compile-fixes-3.8/20121026132711/
Due to underlying problems in v3.7-rc2, several tests fail. These
failures are unrelated to these patches.
Commit 4c98dc6b8e ("ARM: OMAP: Make
plat/fpga.h local to arch/arm/plat-omap") results in a new warning from
sparse:
arch/arm/mach-omap1/fpga.c:147:6: warning: symbol 'omap1510_fpga_init_irq' was not declared. Should it be static?
Fix by adding a missing include.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Commit 25c7d49ed4 ("ARM: OMAP: Make
omap_device local to mach-omap2") broke an OMAP5912-only build here:
arch/arm/mach-omap1/pm_bus.c: In function 'omap1_pm_runtime_init':
arch/arm/mach-omap1/pm_bus.c:69:2: error: implicit declaration of function
'cpu_class_is_omap1'
make[1]: *** [arch/arm/mach-omap1/pm_bus.o] Error 1
Fix by adding a missing include.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Tony Lindgren <tony@atomide.com>
Commit b7754452b3 ("mtd: onenand: omap:
use pdata info instead of cpu_is") broke an OMAP3+4 build and an N800
multi-OMAP2xxx build here:
drivers/built-in.o: In function `omap2_onenand_probe':
drivers/mtd/onenand/omap2.c:742: undefined reference to `omap2_onenand_read_bufferram'
drivers/mtd/onenand/omap2.c:743: undefined reference to `omap2_onenand_write_bufferram'
drivers/mtd/onenand/omap2.c:742: undefined reference to `omap2_onenand_read_bufferram'
drivers/mtd/onenand/omap2.c:743: undefined reference to `omap2_onenand_write_bufferram'
...
drivers/built-in.o: In function `omap2_onenand_probe':
drivers/mtd/onenand/omap2.c:788: undefined reference to `omap3_onenand_read_bufferram'
drivers/mtd/onenand/omap2.c:788: undefined reference to `omap3_onenand_write_bufferram'
Fix by declaring static functions for the missing symbols, rather than
just prototypes.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Afzal Mohammed <afzal@ti.com>
Cc: Tony Lindgren <tony@atomide.com>
Prepares for the future move of the PRM/CM code to drivers/. Also
includes some prcm.[ch] cleanup patches from the WDTIMER cleanup
series that don't need external acks.
Basic test logs for this branch on top of v3.7-rc2 are here:
http://www.pwsan.com/omap/testlogs/prcm_cleanup_a_3.8/20121021123719/
But due to the number of unrelated regressions present in v3.7-rc[12],
it's not particularly usable as a testing base. With reverts, fixes,
and workarounds applied as documented in:
http://www.pwsan.com/omap/testlogs/test_v3.7-rc2/20121020134755/README.txt
the following test logs were obtained:
http://www.pwsan.com/omap/testlogs/prcm_cleanup_a_3.8/20121020231757/
which indicate that the series tests cleanly.
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Merge tag 'omap-cleanup-a-for-3.8' of git://git.kernel.org/pub/scm/linux/kernel/git/pjw/omap-pending into omap-for-v3.8/cleanup-prcm
The first set of OMAP PRM/CM-related cleanup patches for 3.8.
Prepares for the future move of the PRM/CM code to drivers/. Also
includes some prcm.[ch] cleanup patches from the WDTIMER cleanup
series that don't need external acks.
Basic test logs for this branch on top of v3.7-rc2 are here:
http://www.pwsan.com/omap/testlogs/prcm_cleanup_a_3.8/20121021123719/
But due to the number of unrelated regressions present in v3.7-rc[12],
it's not particularly usable as a testing base. With reverts, fixes,
and workarounds applied as documented in:
http://www.pwsan.com/omap/testlogs/test_v3.7-rc2/20121020134755/README.txt
the following test logs were obtained:
http://www.pwsan.com/omap/testlogs/prcm_cleanup_a_3.8/20121020231757/
which indicate that the series tests cleanly.
Conflicts:
arch/arm/mach-omap2/Makefile
arch/arm/mach-omap2/clockdomain2xxx_3xxx.c
arch/arm/mach-omap2/pm24xx.c
In order to make single zImage work for ARM architecture,
we need to make sure we don't depend on private headers.
Move USB platform_data to <linux/platform_data/omap-usb.h>
and add a minimal drivers/mfd/usb-omap.h.
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Partha Basak <parthab@india.ti.com>
Cc: Keshava Munegowda <keshava_mgowda@ti.com>
Cc: linux-usb@vger.kernel.org
Signed-off-by: Felipe Balbi <balbi@ti.com>
[tony@atomide.com: updated for local mfd/usb-omap.h]
Signed-off-by: Tony Lindgren <tony@atomide.com>
Let's move what we can from plat/usb.h to the local usb.h
for ARM common zImage support.
This is needed so we can remove plat/usb.h for ARM common
zImage support.
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Partha Basak <parthab@india.ti.com>
Cc: Keshava Munegowda <keshava_mgowda@ti.com>
Cc: linux-usb@vger.kernel.org
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
For omap1, we'll keep mach/serial.h around for 8250.c hardware
workarounds. For omap2+, we no longer need mach/serial.h and
can make it local to mach-omap2.
Signed-off-by: Tony Lindgren <tony@atomide.com>
This allows us to eventually move omap2+ to generic
debug code that's configured in Kconfig for the port.
Signed-off-by: Tony Lindgren <tony@atomide.com>
window to remove most of the remaining plat includes to get us
closer to ARM common zImage support.
To avoid a huge amount of trivial merge conflicts with includes,
this branch is based on several small topic branches coordinated
with the driver subsystem maintainers. These branches are based on
v3.7-rc1 and can also be merged into the related driver subsystem
branches as needed:
omap-for-v3.8/cleanup-headers-prepare few trivial driver changes
omap-for-v3.8/cleanup-headers-dma move of the DMA header
omap-for-v3.8/cleanup-headers-gpmc GPMC and MTD changes
omap-for-v3.8/cleanup-headers-mmc MMC related changes
omap-for-v3.8/cleanup-headers-dss DSS related changes
omap-for-v3.8/cleanup-headers-asoc ASoC related changes
Note that for the dma-omap.h, it was decided that it should be
is completed. For the related discussion, please see:
https://patchwork.kernel.org/patch/1519591/#
After these patches we still have a few plat headers remaining
that will be handled in later pull requests.
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Merge tag 'omap-for-v3.8/cleanup-headers-signed' into omap-for-v3.8/cleanup-headers-serial-take2
This is the first set of omap cleanup patches for v3.8 merge
window to remove most of the remaining plat includes to get us
closer to ARM common zImage support.
To avoid a huge amount of trivial merge conflicts with includes,
this branch is based on several small topic branches coordinated
with the driver subsystem maintainers. These branches are based on
v3.7-rc1 and can also be merged into the related driver subsystem
branches as needed:
omap-for-v3.8/cleanup-headers-prepare few trivial driver changes
omap-for-v3.8/cleanup-headers-dma move of the DMA header
omap-for-v3.8/cleanup-headers-gpmc GPMC and MTD changes
omap-for-v3.8/cleanup-headers-mmc MMC related changes
omap-for-v3.8/cleanup-headers-dss DSS related changes
omap-for-v3.8/cleanup-headers-asoc ASoC related changes
Note that for the dma-omap.h, it was decided that it should be
is completed. For the related discussion, please see:
https://patchwork.kernel.org/patch/1519591/#
After these patches we still have a few plat headers remaining
that will be handled in later pull requests.
This allows us to get rid of the ifdefs in 8250.c.
Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Modify divisor to select the nearest baud rate divider rather than the
lowest. It minimizes baud rate errors especially on low UART clock
frequencies.
For example, if uartclk is 33000000 and baud is 115200 the ratio is
about 17.9 The current code selects 17 (5% error) but should select 18
(0.5% error).
This 5% error in baud rate leads to garbage on receiving end, while 0.5%
doesn't.
The issue showed up when using the stock 8250 driver for
Synopsys DW UART. This was on a FPGA with ~12MHz UART clock.
When we enabled early serial, we saw garbage which was narrowed down
to the rounding error.
So the bug had been latent and it only showed up with such low clock rates.
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Convert clk_enable/clk_disable to clk_prepare_enable/clk_disable_unprepare
calls as required by common clock framework.
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a driver has the low_latency flag set and uses the schedule_flip()
function to initiate copying data to the line discipline, a workqueue is
scheduled in but never actually flushed. This is incorrect use of the
low_latency flag (driver should not support the low_latency flag, or use
the tty_flip_buffer_push() function instead). Make sure a warning is
reported to catch incorrect use of the low_latency flag.
This patch goes with: cee4ad1ed9
Signed-off-by: Ivo Sieben <meltedpianoman@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Instead of BUG_ON(in_interrupt()), since that doesn't check for all
the newfangled stuff like preempt.
Note that this is valid since the console_sem is essentially used like
a real mutex with only two twists:
- we allow trylock from hardirq context
- across suspend/resume we lock the logical console_lock, but drop the
semaphore protecting the locking state.
Now that doesn't guarantee that no one is playing tricks in
single-thread atomic contexts at suspend/resume/boot time, but
- I couldn't find anything suspicious with some grepping,
- might_sleep shouldn't die,
- and I think the upside of catching more potential issues is worth
the risk of getting a might_sleep backtrace that would have been
save (and then dealing with that fallout).
Cc: Dave Airlie <airlied@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
So this is it. The big step why we did all the work over the past
kernel releases. Now everything is prepared, so nothing protects us
from doing that big step.
| | \ \ nnnn/^l | |
| | \ / / | |
| '-,.__ => \/ ,-` => | '-,.__
| O __.´´) ( .` | O __.´´)
~~~ ~~ `` ~~~ ~~
The buffers are now in the tty_port structure and we can start
teaching the buffer helpers (insert char/string, flip etc.) to use
tty_port instead of tty_struct all around.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
For that purpose we have to temporarily introduce a second tty back
pointer into tty_port. It is because serial layer, and maybe others,
still do not use tty_port_tty_set/get. So that we cannot set the
tty_port->tty to NULL at will now.
Yes, the fix would be to convert whole serial layer and all its users
to tty_port_tty_set/get. However we are in the process of removing the
need of tty in most of the call sites, so this would lead to a
duplicated work.
Instead we have now tty_port->itty (internal tty) which will be used
only in flush_to_ldisc. For that one it is ensured that itty is valid
wherever the work is run. IOW, the work is synchronously cancelled
before we set itty to NULL and also before hangup is processed.
After we need only tty_port and not tty_struct in most code, this
shall be changed to tty_port_tty_set/get and itty removed completely.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
During the move of tty buffers from tty_struct to tty_port, we will
need to switch all users of buf to tty->port->buf. There are many
functions where this is accessed directly in their code many times.
Cache the tty->buf pointer in such functions now and change only
single lines in each function in the next patch.
Not that it is convenient for the next patch, but the code is now also
more readable.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
They are only TTY buffers specific. And the buffers will go to
tty_port in the next patches. So to remove the need to have both
tty_port and tty_struct at some places, let us move the flags to
tty_port.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
In some funtions we need only n_tty_data, so pass it down directly in
case tty is not needed there.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
atomic_write_lock is not n_tty specific, so move it up in the
tty_struct.
And since these are the last ones to move, remove also the comment
saying there are some ldisc' members. There are none now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All the ring-buffers...
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here we move bitmaps and use DECLARE_BITMAP to declare them in the new
structure. And instead of memset, we use bitmap_zero as it is more
appropriate.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Here we start moving all the n_tty related bits from tty_struct to
the newly defined n_tty_data struct in n_tty proper.
In this patch primitive members and bits are moved. The rest will be
done per-partes in the next patches.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
All n_tty related members from tty_struct will be moved here.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This is a private member of n_tty. Stop accessing it. Instead, take is
as an argument.
This is needed to allow clean switch of the private members to a
separate private structure of n_tty.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* BUG_ON(!tty) in n_tty_set_termios -- it cannot be called with tty ==
NULL. It is called from two call sites. First, from n_tty_open where
we have a valid tty. Second, as ld->ops->set_termios from
tty_set_termios. But there we have a valid tty too.
* if (!tty) in n_tty_open -- why would the TTY layer call ldisc's
open with an invalid TTY? No it indeed does not. All call sites have
a tty and dereference that.
* BUG_ON(!tty->read_buf) in n_tty_read -- this used to be a valid
check. The ldisc handling was broken some time ago when I added the
check to ensure everything is OK. It still can catch the case, but
no later than we move the buffer to ldisc data. Then there will be
no read_buf in tty_struct, i.e. nothing to check for.
* if (!tty->read_buf) in n_tty_receive_buf -- this should never
happen. All callers of ldisc->ops->receive_ops should hold a
reference to an ldisc and close (which frees read_buf) cannot be
called until the reference is dropped.
* if (WARN_ON(!tty->read_buf)) in n_tty_read -- the same as in the
previous case.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ldisc->open and close are called only once and cannot cross. So the
tests in open and close are superfluous. Remove them. (But leave sets
to NULL to ensure there is not a bug somewhere.)
And when the tests are gone, handle properly failures in open. We
leaked read_buf if allocation of echo_buf failed before. Now this is
not the case anymore.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hci_ldisc's open checks if tty_struct->disc_data is set. And if so it
returns with an error. But nothing ensures disc_data to be NULL. And
since ld->ops->open shall be called only once, we do not need the
check at all. So remove it.
Note that this is not an issue now, but n_tty will start using the
disc_data pointer and this invalid 'if' would trigger then rendering
TTYs over BT unusable.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: Johan Hedberg <johan.hedberg@gmail.com>
Cc: linux-bluetooth@vger.kernel.org
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We reintroduced tty_ldisc_wait_idle in 100eeae2c5 (TTY: restore
tty_ldisc_wait_idle) and used in set_ldisc. Then we added it also to
the hangup path in 92f6fa09bd (TTY: ldisc, do not close until there
are readers). And we noted that there is one more path:
~ Before 65b770468e tty_ldisc_wait_idle was called also from
~ tty_ldisc_release. It is called from tty_release, so I don't think
~ we need to restore that one.
Well, I was wrong. There might still be holders of an ldisc
reference. Not from userspace, but drivers. If they take a reference
and a user closes the device immediately after that, we have a
problem. ldisc is halted and closed by TTY, but the driver still may
call some ldisc's operation and cause a crash.
So restore the tty_ldisc_wait_idle call also to the third location
where it was before 65b770468e (tty-ldisc: turn ldisc user count
into a proper refcount). Now we should be safe with respect to the
ldisc reference counting as all* tty_ldisc_close paths are safely
called with reference count of one.
* Not the one in tty_ldisc_setup's fail path. But that is called
before the first open finishes. So userspace does not see it yet.
Even thought the driver is given the TTY already via ->install, it
should not take a reference to the ldisc yet. If some driver is to
do this, we should put one tty_ldisc_wait_idle also in the setup.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
There used to be a single tty_ldisc_ref_wait. But then, when a
big-tty-mutex (BTM) was introduced, it has to be tty_ldisc_ref +
tty_unlock + tty_ldisc_ref_wait + tty_lock. Later, BTM was removed
from that path and tty_ldisc_ref + tty_ldisc_ref_wait remained there.
But it makes no sense now. So leave there only tty_ldisc_ref_wait.
And when we have a reference to an ldisc, actually use it in the loop.
Otherwise it may be racy.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Now that we have control over tty->driver_data in pty, we can just
kill the /dev/pts/ in pty code too. Namely, in ->shutdown hook of
tty. For pty, this is called only once, for whichever end is closed
last. But we don't care, both driver_data are the inode as it used to
be till now.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The goal is to stop setting and using tty->driver_data in devpts code.
It should be used solely by the driver's code, pty in this case.
Now driver_data are managed only in the pty driver. devpts_pty_new is
switched to accept what we used to dig out of tty_struct, i.e. device
node number and index.
This also removes a note about driver_data being set outside of the
driver.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The goal is to stop setting and using tty->driver_data in devpts code.
It should be used solely by the driver's code, pty in this case.
For the cleanup of layering, we will need the inode created in
devpts_pty_new to be stored into slave's driver_data. So we convert
devpts_pty_new to return the inode or an ERR_PTR-encoded error in case
of failure.
The move of 'inode = new_inode(sb);' from declarators to the code is
only cosmetical, but it makes the code easier to read.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The goal is to stop setting and using tty->driver_data in devpts code.
It should be used solely by the driver's code, pty in this case.
First, here we remove TTY from devpts_get_tty and rename it to
devpts_get_priv. Note we do not remove type safety, we just shift the
[implicit] (void *) cast one layer up.
index was unused in devpts_get_tty, so remove that from the prototype
too.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When low_latency flag is set the TTY receive flip buffer is copied to the
line discipline directly instead of using a work queue in the background.
Therefor only in case a workqueue is actually used for copying data to the
line discipline we'll have to flush the workqueue.
This prevents unnecessary spin lock/unlock on the workqueue spin lock that
can cause additional scheduling overhead on a PREEMPT_RT system. On a 200
MHz AT91SAM9261 processor setup this fixes about 100us of scheduling
overhead on the TTY read call.
Signed-off-by: Ivo Sieben <meltedpianoman@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Dave Airlie recently discovered a locking bug in the fbcon layer,
where a timer_del_sync (for the blinking cursor) deadlocks with the
timer itself, since both (want to) hold the console_lock:
https://lkml.org/lkml/2012/8/21/36
Unfortunately the console_lock isn't a plain mutex and hence has no
lockdep support. Which resulted in a few days wasted of tracking down
this bug (complicated by the fact that printk doesn't show anything
when the console is locked) instead of noticing the bug much earlier
with the lockdep splat.
Hence I've figured I need to fix that for the next deadlock involving
console_lock - and with kms/drm growing ever more complex locking
that'll eventually happen.
Now the console_lock has rather funky semantics, so after a quick irc
discussion with Thomas Gleixner and Dave Airlie I've quickly ditched
the original idead of switching to a real mutex (since it won't work)
and instead opted to annotate the console_lock with lockdep
information manually.
There are a few special cases:
- The console_lock state is protected by the console_sem, and usually
grabbed/dropped at _lock/_unlock time. But the suspend/resume code
drops the semaphore without dropping the console_lock (see
suspend_console/resume_console). But since the same thread that did
the suspend will do the resume, we don't need to fix up anything.
- In the printk code there's a special trylock, only used to kick off
the logbuffer printk'ing in console_unlock. But all that happens
while lockdep is disable (since printk does a few other evil
tricks). So no issue there, either.
- The console_lock can also be acquired form irq context (but only
with a trylock). lockdep already handles that.
This all leaves us with annotating the normal console_lock, _unlock
and _trylock functions.
And yes, it works - simply unloading a drm kms driver resulted in
lockdep complaining about the deadlock in fbcon_deinit:
======================================================
[ INFO: possible circular locking dependency detected ]
3.6.0-rc2+ #552 Not tainted
-------------------------------------------------------
kms-reload/3577 is trying to acquire lock:
((&info->queue)){+.+...}, at: [<ffffffff81058c70>] wait_on_work+0x0/0xa7
but task is already holding lock:
(console_lock){+.+.+.}, at: [<ffffffff81264686>] bind_con_driver+0x38/0x263
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (console_lock){+.+.+.}:
[<ffffffff81087440>] lock_acquire+0x95/0x105
[<ffffffff81040190>] console_lock+0x59/0x5b
[<ffffffff81209cb6>] fb_flashcursor+0x2e/0x12c
[<ffffffff81057c3e>] process_one_work+0x1d9/0x3b4
[<ffffffff810584a2>] worker_thread+0x1a7/0x24b
[<ffffffff8105ca29>] kthread+0x7f/0x87
[<ffffffff813b1204>] kernel_thread_helper+0x4/0x10
-> #0 ((&info->queue)){+.+...}:
[<ffffffff81086cb3>] __lock_acquire+0x999/0xcf6
[<ffffffff81087440>] lock_acquire+0x95/0x105
[<ffffffff81058cab>] wait_on_work+0x3b/0xa7
[<ffffffff81058dd6>] __cancel_work_timer+0xbf/0x102
[<ffffffff81058e33>] cancel_work_sync+0xb/0xd
[<ffffffff8120a3b3>] fbcon_deinit+0x11c/0x1dc
[<ffffffff81264793>] bind_con_driver+0x145/0x263
[<ffffffff81264a45>] unbind_con_driver+0x14f/0x195
[<ffffffff8126540c>] store_bind+0x1ad/0x1c1
[<ffffffff8127cbb7>] dev_attr_store+0x13/0x1f
[<ffffffff8116d884>] sysfs_write_file+0xe9/0x121
[<ffffffff811145b2>] vfs_write+0x9b/0xfd
[<ffffffff811147b7>] sys_write+0x3e/0x6b
[<ffffffff813b0039>] system_call_fastpath+0x16/0x1b
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(console_lock);
lock((&info->queue));
lock(console_lock);
lock((&info->queue));
*** DEADLOCK ***
v2: Mark the lockdep_map static, noticed by Jani Nikula.
Cc: Dave Airlie <airlied@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The OMAP watchdog timer driver needs to determine what caused the SoC
to reset for its GETBOOTSTATUS ioctl. So, define a set of standard
reset sources across OMAP SoCs. For OMAP2xxx, 3xxx, and 4xxx SoCs,
define mappings from the SoC-specific reset source register bits to
the standardized reset source IDs. Create SoC-specific PRM functions
that read the appropriate per-SoC register and use the mapping to
return the standardized reset bits. Register the SoC-specific PRM
functions with the common PRM code via prm_register(). Create a
function in the common PRM code, prm_read_reset_sources(), that
calls the SoC-specific function, registered during boot.
This patch does not yet handle some SoCs, such as AM33xx. Those SoCs
were not handled by the code this will replace.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
On OMAP1, the existing OMAP watchdog driver reads a register directly
from a non-watchdog IP block. It also does not convert the register's
contents into the standard WDIOF_* bits expected from the
GETBOOTSTATUS ioctl().
To move towards fixing these problems, create an function in
arch/arm/mach-omap1 to return the reset source data. A subsequent
patch will provide this function to the watchdog driver via
platform_data.
In the long term, the best approach would be to move this function
to a new OMAP1 driver that handles access to the OMAP1 Clock
Generation and Reset Management IP block. Then no platform_data would
be needed.
Signed-off-by: Paul Walmsley <paul@pwsan.com>
