In DMA support, The received data is not pushed to tty until the DMA buffer
is filled. But some megabyte rate chips such as BT expect fast response and
data should be pushed immediately. In order to fix this issue, We suggest
the use of the timer for polling DMA buffer.
In our test, no data loss occurred at high-baudrate as compared with interrupt-
driven (We tested with 3Mbps).
We changes:
- We add timer for polling. If we set poll_timer to 10, every 10ms,
timer handler checks the residue in the dma buffer and transfer data
to the tty. Also, last_residue is updated for the next polling.
- poll_timeout is used to prevent the timer's system cost.
If poll_timeout is set to 3000 and no data is received in 3 seconds,
we inactivate poll timer and driver falls back to interrupt-driven.
When data is received again in FIFO and UART irq is occurred, we switch
back to DMA mode and start polling.
- We use consistent DMA mappings to avoid from the frequent cache operation
of the timer function for default.
- pl011_dma_rx_chars is modified. the pending size is recalculated because
data can be taken by polling.
- the polling time is adjusted if dma rx poll is enabled but no rate is
specified. Ideal polling interval to push 1 character at every interval
is the reciprocal of 'baud rate / 10 line bits per character / 1000 ms
per sec'. But It is very aggressive to system. Experimentally,
'10000000 / baud' is suitable to receive dozens of characters. the poll rate
can be specified statically by dma_rx_poll_rate of the platform data as well.
Changes compared to v1:
- Use of consistent DMA mappings.
- Added dma_rx_poll_rate in platform data to specify the polling interval.
- Added dma_rx_poll_timeout in platform data to specify the polling timeout.
Changes compared to v2:
- Use of consistent DMA mappings for default.
- Added dma_rx_poll_enable in platform data to adjust the polling time
according to the baud rate.
- remove unnecessary lock from the polling function.
Signed-off-by: Chanho Min <chanho.min@lge.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty_ldisc_hangup() guarantees the ldisc is enabled (or that there
is no ldisc). Since __tty_hangup() was the only user, re-define
tty_ldisc_enable() in file-scope.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Flip buffer work must not be scheduled by the line discipline
after the line discipline has been halted; issue warning.
Note: drivers can still schedule flip buffer work.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It allows for cleaning up on a considerable amount of places. They did
port_get, hangup, kref_put. Now the only thing needed is to call
tty_port_tty_hangup which does exactly that. And they can also decide
whether to consider CLOCAL or completely ignore that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
It allows for cleaning up on a considerable amount of places. They did
port_get, wakeup, kref_put. Now the only thing needed is to call
tty_port_tty_wakeup which does exactly that.
One exception is ifx6x60 where tty_wakeup was open-coded. We now call
tty_wakeup properly there.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The warning is there since 2.1.69 and we have not seen anybody
reporting it in the past decade. Remove the warning now.
tty_get_baud_rate can now be inline. This gives us one less
EXPORT_SYMBOL.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The tty driver can become stuck throttled due to race conditions
between throttle and unthrottle, when the decision to throttle
or unthrottle is conditional. The following example helps to
illustrate the race:
CPU 0 | CPU 1
|
if (condition A) |
| <processing such that A not true>
| if (!condition A)
| unthrottle()
throttle() |
|
Note the converse is also possible; ie.,
CPU 0 | CPU 1
|
| if (!condition A)
<processing such that A true> |
if (condition A) |
throttle() |
| unthrottle()
|
Add new throttle/unthrottle functions based on the familiar model
of task state and schedule/wake. For example,
while (1) {
tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
if (!condition)
break;
if (!tty_throttle_safe(tty))
break;
}
__tty_set_flow_change(tty, 0);
In this example, if an unthrottle occurs after the condition is
evaluated but before tty_throttle_safe(), then tty_throttle_safe()
will return non-zero, looping and forcing the re-evaluation of
condition.
Reported-by: Vincent Pillet <vincentx.pillet@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Commit 1d9d8639c0 ("perf,x86: fix kernel crash with PEBS/BTS after
suspend/resume") introduces a link failure since
perf_restore_debug_store() is only defined for CONFIG_CPU_SUP_INTEL:
arch/x86/power/built-in.o: In function `restore_processor_state':
(.text+0x45c): undefined reference to `perf_restore_debug_store'
Fix it by defining the dummy function appropriately.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull MFD fixes from Samuel Ortiz:
"This is the first batch of MFD fixes for 3.9.
With this one we have:
- An ab8500 build failure fix.
- An ab8500 device tree parsing fix.
- A fix for twl4030_madc remove routine to work properly (when
built-in).
- A fix for properly registering palmas interrupt handler.
- A fix for omap-usb init routine to actually write into the
hostconfig register.
- A couple of warning fixes for ab8500-gpadc and tps65912"
* tag 'mfd-fixes-3.9-1' of git://git.kernel.org/pub/scm/linux/kernel/git/sameo/mfd-fixes:
mfd: twl4030-madc: Remove __exit_p annotation
mfd: ab8500: Kill "reg" property from binding
mfd: ab8500-gpadc: Complain if we fail to enable vtvout LDO
mfd: wm831x: Don't forward declare enum wm831x_auxadc
mfd: twl4030-audio: Fix argument type for twl4030_audio_disable_resource()
mfd: tps65912: Declare and use tps65912_irq_exit()
mfd: palmas: Provide irq flags through DT/platform data
mfd: Make AB8500_CORE select POWER_SUPPLY to fix build error
mfd: omap-usb-host: Actually update hostconfig
This patch fixes a kernel crash when using precise sampling (PEBS)
after a suspend/resume. Turns out the CPU notifier code is not invoked
on CPU0 (BP). Therefore, the DS_AREA (used by PEBS) is not restored properly
by the kernel and keeps it power-on/resume value of 0 causing any PEBS
measurement to crash when running on CPU0.
The workaround is to add a hook in the actual resume code to restore
the DS Area MSR value. It is invoked for all CPUS. So for all but CPU0,
the DS_AREA will be restored twice but this is harmless.
Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull fix for hlist_entry_safe() regression from Paul McKenney:
"This contains a single commit that fixes a regression in
hlist_entry_safe(). This macro references its argument twice, which
can cause NULL-pointer errors. This commit applies a gcc statement
expression, creating a temporary variable to avoid the double
reference. This has been posted to LKML at
https://lkml.org/lkml/2013/3/9/75.
Kudos to CAI Qian, whose testing uncovered this, to Eric Dumazet, who
spotted root cause, and to Li Zefan, who tested this commit."
* 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
list: Fix double fetch of pointer in hlist_entry_safe()
The current version of hlist_entry_safe() fetches the pointer twice,
once to test for NULL and the other to compute the offset back to the
enclosing structure. This is OK for normal lock-based use because in
that case, the pointer cannot change. However, when the pointer is
protected by RCU (as in "rcu_dereference(p)"), then the pointer can
change at any time. This use case can result in the following sequence
of events:
1. CPU 0 invokes hlist_entry_safe(), fetches the RCU-protected
pointer as sees that it is non-NULL.
2. CPU 1 invokes hlist_del_rcu(), deleting the entry that CPU 0
just fetched a pointer to. Because this is the last entry
in the list, the pointer fetched by CPU 0 is now NULL.
3. CPU 0 refetches the pointer, obtains NULL, and then gets a
NULL-pointer crash.
This commit therefore applies gcc's "({ })" statement expression to
create a temporary variable so that the specified pointer is fetched
only once, avoiding the above sequence of events. Please note that
it is the caller's responsibility to use rcu_dereference() as needed.
This allows RCU-protected uses to work correctly without imposing
any additional overhead on the non-RCU case.
Many thanks to Eric Dumazet for spotting root cause!
Reported-by: CAI Qian <caiqian@redhat.com>
Reported-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Li Zefan <lizefan@huawei.com>
Merge misc fixes from Andrew Morton:
- A bunch of fixes
- Finish off the idr API conversions before someone starts to use the
old interfaces again.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
idr: idr_alloc() shouldn't trigger lowmem warning when preloaded
UAPI: fix endianness conditionals in M32R's asm/stat.h
UAPI: fix endianness conditionals in linux/raid/md_p.h
UAPI: fix endianness conditionals in linux/acct.h
UAPI: fix endianness conditionals in linux/aio_abi.h
decompressors: fix typo "POWERPC"
mm/fremap.c: fix oops on error path
idr: deprecate idr_pre_get() and idr_get_new[_above]()
tidspbridge: convert to idr_alloc()
zcache: convert to idr_alloc()
mlx4: remove leftover idr_pre_get() call
workqueue: convert to idr_alloc()
nfsd: convert to idr_alloc()
nfsd: remove unused get_new_stid()
kernel/signal.c: use __ARCH_HAS_SA_RESTORER instead of SA_RESTORER
signal: always clear sa_restorer on execve
mm: remove_memory(): fix end_pfn setting
include/linux/res_counter.h needs errno.h
Now that all in-kernel users are converted to ues the new alloc
interface, mark the old interface deprecated. We should be able to
remove these in a few releases.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alpha allmodconfig:
In file included from mm/memcontrol.c:28:
include/linux/res_counter.h: In function 'res_counter_set_limit':
include/linux/res_counter.h:203: error: 'EBUSY' undeclared (first use in this function)
include/linux/res_counter.h:203: error: (Each undeclared identifier is reported only once
include/linux/res_counter.h:203: error: for each function it appears in.)
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Glauber Costa <glommer@parallels.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull USB fixes from Greg Kroah-Hartman:
"Here are a number of tiny USB fixes and new USB device ids for your
3.9 tree.
The "largest" one here is a revert of a usb-storage patch that turned
out to be incorrect, breaking existing users, which is never a good
thing. Everything else is pretty simple and small"
* tag 'usb-3.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (43 commits)
USB: quatech2: only write to the tty if the port is open.
qcserial: bind to DM/DIAG port on Gobi 1K devices
USB: cdc-wdm: fix buffer overflow
usb: serial: Add Rigblaster Advantage to device table
qcaux: add Franklin U600
usb: musb: core: fix possible build error with randconfig
usb: cp210x new Vendor/Device IDs
usb: gadget: pxa25x: fix disconnect reporting
usb: dwc3: ep0: fix sparc64 build
usb: c67x00 RetryCnt value in c67x00 TD should be 3
usb: Correction to c67x00 TD data length mask
usb: Makefile: fix drivers/usb/phy/ Makefile entry
USB: added support for Cinterion's products AH6 and PLS8
usb: gadget: fix omap_udc build errors
USB: storage: fix Huawei mode switching regression
USB: storage: in-kernel modeswitching is deprecated
tools: usb: ffs-test: Fix build failure
USB: option: add Huawei E5331
usb: musb: omap2430: fix sparse warning
usb: musb: omap2430: fix omap_musb_mailbox glue check again
...
Pull staging tree fixes from Greg Kroah-Hartman:
"Here are some drivers/staging and drivers/iio fixes for 3.9 (the two
are still pretty intertwined, hence them coming both from my tree
still.) Nothing major, just a few things that have been reported by
users, all of these have been in linux-next for a while."
* tag 'staging-3.9-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
staging: comedi: dt9812: use CR_CHAN() for channel number
staging/vt6656: Fix too large integer constant warning on 32-bit
staging: comedi: drivers: usbduxsigma.c: fix DMA buffers on stack
staging: imx/drm: request irq only after adding the crtc
staging: comedi: drivers: usbduxfast.c: fix for DMA buffers on stack
staging: comedi: drivers: usbdux.c: fix DMA buffers on stack
staging: vt6656: Fix oops on resume from suspend.
iio:common:st_sensors fixed all warning messages about uninitialized variables
iio: Fix build error seen if IIO_TRIGGER is defined but IIO_BUFFER is not
iio/imu: inv_mpu6050 depends on IIO_BUFFER
iio:ad5064: Initialize register cache correctly
iio:ad5064: Fix off by one in DAC value range check
iio:ad5064: Fix address of the second channel for ad5065/ad5045/ad5025
Fix new kernel-doc warnings in idr:
Warning(include/linux/idr.h:113): No description found for parameter 'idr'
Warning(include/linux/idr.h:113): Excess function parameter 'idp' description in 'idr_find'
Warning(lib/idr.c:232): Excess function parameter 'id' description in 'sub_alloc'
Warning(lib/idr.c:232): Excess function parameter 'id' description in 'sub_alloc'
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Clean up interrupts on exit, silencing a sparse warning caused by
tps65912_irq_exit() being defined but not prototyped as we go.
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Currently driver sets the irq type to IRQF_TRIGGER_LOW which is
causing interrupt registration failure in ARM based SoCs as:
[ 0.208479] genirq: Setting trigger mode 8 for irq 118 failed (gic_set_type+0x0/0xf0)
[ 0.208513] dummy 0-0059: Failed to request IRQ 118: -22
Provide the irq flags through platform data if device is registered
through board file or get the irq type from DT node property in place
of hardcoding the irq flag in driver to support multiple platforms.
Also configure the device to generate the interrupt signal according to
flag type.
Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
Pull namespace bugfixes from Eric Biederman:
"This is three simple fixes against 3.9-rc1. I have tested each of
these fixes and verified they work correctly.
The userns oops in key_change_session_keyring and the BUG_ON triggered
by proc_ns_follow_link were found by Dave Jones.
I am including the enhancement for mount to only trigger requests of
filesystem modules here instead of delaying this for the 3.10 merge
window because it is both trivial and the kind of change that tends to
bit-rot if left untouched for two months."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: Use nd_jump_link in proc_ns_follow_link
fs: Limit sys_mount to only request filesystem modules (Part 2).
fs: Limit sys_mount to only request filesystem modules.
userns: Stop oopsing in key_change_session_keyring
This same driver can be used by atmel based touchscreens and touchpads
(buttonpads). Platform data may specify a device is a touchpad
using the is_tp flag.
This will cause the driver to perform some touchpad specific
initializations, such as:
* register input device name "Atmel maXTouch Touchpad" instead of
Touchscreen.
* register BTN_LEFT & BTN_TOOL_* event types.
* register axis resolution (as a fixed constant, for now)
* register BUTTONPAD property
* process GPIO buttons using reportid T19
Input event GPIO mapping is done by the platform data key_map array.
key_map[x] should contain the KEY or BTN code to send when processing
GPIOx from T19. To specify a GPIO as not an input source, populate
with KEY_RESERVED, or 0.
Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Signed-off-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
