While porting a RS485 driver from 2.6.29 to 3.14, i noticed that the serial tty
driver could break it by using uart ports that it does not own :
1. uart_change_pm ist called during uart_open and calls the uart pm function
without checking for PORT_UNKNOWN.
The fix is to move uart_change_pm from uart_open to uart_port_startup.
2. The return code from the uart request_port call in uart_set_info is not
handled properly, leading to the situation that the serial driver also
thinks it owns the uart ports.
This can triggered by doing following actions :
setserial /dev/ttyS0 uart none # release the uart ports
modprobe lirc-serial # or any other device that uses the uart
setserial /dev/ttyS0 uart 16550 # gives no error and the uart tty driver
# can use the ports as well
Signed-off-by: Thomas Pfaff <tpfaff@pcs.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The two functions to write out to the console (one used in normal
console mode and one in polling console mode) were slightly different.
One used a barrier() in its loop and the other a cpu_relax(). The
barrier() really doesn't do anything since we're using rd_regl() to
read the port anyway. Switch it to cpu_relax() to make things
consistent.
No known bugs / issues are fixed by this change--it just makes things
more consistent.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The s3c24xx_serial_console_putchar() is _only_ ever used by
s3c24xx_serial_console_write() and is called in a loop (indirectly
through uart_console_write()). There's no reason to call
s3c24xx_port_configured() for every iteration through the loop. Move
it outside the loop.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The two functions in the samsung serial driver used for writing
characters out to the port were inconsistent about whether they used
the passed in "port" or the global "cons_uart". There was no reason
to use the global and the use of the global in
s3c24xx_serial_put_poll_char() caused a crash in the case where you
used the serial port for kgdboc but not for console.
Fix it so we used the passed in variable.
Note that this doesn't fix all problems with the samsung serial
driver. Specifically:
* s3c24xx_serial_console_putchar() is still 99% identical to
s3c24xx_serial_put_poll_char() (the function signature is different,
but that's about it). A future patch will make them slightly less
identical and judging by other serial drivers we may need yet more
differences eventually.
* The samsung serial driver still doesn't allow you to have more than
one console port since it still uses the global cons_uart in
s3c24xx_serial_console_write().
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
__dma_tx_complete is not protected against concurrent
call of serial8250_tx_dma. it can lead to circular tail
index corruption or parallel call of serial_tx_dma on the
same data portion.
This patch fixes this issue by holding the port lock.
Signed-off-by: Loic Poulain <loic.poulain@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The race was introduced while development of linux-3.11 by
e8437d7ecb and
e9975fdec0.
Originally it was found and reproduced on linux-3.12.15 and
linux-3.12.15-rt25, by sending 500 byte blocks with 115kbaud to the
target uart in a loop with 100 milliseconds delay.
In short:
1. The consumer flush_to_ldisc is on to remove the head tty_buffer.
2. The producer adds a number of bytes, so that a new tty_buffer must
be allocated and added by __tty_buffer_request_room.
3. The consumer removes the head tty_buffer element, without handling
newly committed data.
Detailed example:
* Initial buffer:
* Head, Tail -> 0: used=250; commit=250; read=240; next=NULL
* Consumer: ''flush_to_ldisc''
* consumed 10 Byte
* buffer:
* Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
{{{
count = head->commit - head->read; // count = 0
if (!count) { // enter
// INTERRUPTED BY PRODUCER ->
if (head->next == NULL)
break;
buf->head = head->next;
tty_buffer_free(port, head);
continue;
}
}}}
* Producer: tty_insert_flip_... 10 bytes + tty_flip_buffer_push
* buffer:
* Head, Tail -> 0: used=250; commit=250; read=250; next=NULL
* added 6 bytes: head-element filled to maximum.
* buffer:
* Head, Tail -> 0: used=256; commit=250; read=250; next=NULL
* added 4 bytes: __tty_buffer_request_room is called
* buffer:
* Head -> 0: used=256; commit=256; read=250; next=1
* Tail -> 1: used=4; commit=0; read=250 next=NULL
* push (tty_flip_buffer_push)
* buffer:
* Head -> 0: used=256; commit=256; read=250; next=1
* Tail -> 1: used=4; commit=4; read=250 next=NULL
* Consumer
{{{
count = head->commit - head->read;
if (!count) {
// INTERRUPTED BY PRODUCER <-
if (head->next == NULL) // -> no break
break;
buf->head = head->next;
tty_buffer_free(port, head);
// ERROR: tty_buffer head freed -> 6 bytes lost
continue;
}
}}}
This patch reintroduces a spin_lock to protect this case. Perhaps later
a lock-less solution could be found.
Signed-off-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Cc: stable <stable@vger.kernel.org> # 3.11
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit f4f653e987.
Jiri writes:
No, please drop this one. We need a better solution as it turned
out that some boxes need 16k loops and it will increase with new
processors :(.
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Martin Pluskal <mpluskal@suse.com>
Cc: Takashi Iwai <tiwai@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
A recent commit ef2889f7ff "serial: pl011:
Move uart_register_driver call to device probe" introduced a regression,
causing the pl011 driver to Oops if more than 1 port have been probed. Fix
the Oops by only calling uart_unregister_driver() once after the last port
has been removed.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The 8250 driver now reports many of these:
serial8250: too much work for irq4
These messages turned out to be common these days with a use of
virtualization. I tried to increase the limit of processed characters
in commit e7328ae184 (serial: 8250,
increase PASS_LIMIT) in 2011. It was raised from 256 to 512, but it is
still not enough, apparently.
So disable the warning unless somebody turns on DEBUG (or
DYNAMIC_DEBUG _and_ the message).
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: Martin Pluskal <mpluskal@suse.com>
Reported-by: Takashi Iwai <tiwai@suse.com>
Tested-by: Takashi Iwai <tiwai@suse.de>
References: https://bugzilla.novell.com/show_bug.cgi?id=868394
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The lack of pm_runtime_resume handling for the device state leads into
device wake-up interrupts not working after a while for runtime PM.
Also, serial-omap is confused about the use of device_may_wakeup.
The checks for device_may_wakeup should only be done for suspend and
resume, not for pm_runtime_suspend and pm_runtime_resume. The wake-up
events for PM runtime should always be enabled.
The lack of pm_runtime_resume handling leads into device wake-up
interrupts not working after a while for runtime PM.
Rather than try to patch over the issue of adding complex tests to
the pm_runtime_resume, let's fix the issues properly:
1. Make serial_omap_enable_wakeup deal with all internal PM state
handling so we don't need to test for up->wakeups_enabled elsewhere.
Later on once omap3 boots in device tree only mode we can also
remove the up->wakeups_enabled flag and rely on the wake-up
interrupt enable/disable state alone.
2. Do the device_may_wakeup checks in suspend and resume only,
for runtime PM the wake-up events need to be always enabled.
3. Finally just call serial_omap_enable_wakeup and make sure we
call it also in pm_runtime_resume.
4. Note that we also have to use disable_irq_nosync as serial_omap_irq
calls pm_runtime_get_sync.
Fixes: 2a0b965cfb (serial: omap: Add support for optional wake-up)
Cc: stable@vger.kernel.org # v3.13+
Signed-off-by: Tony Lindgren <tony@atomide.com>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When a serial port is closed, uart_close() takes care of shutting down the
hardware, and powering it down.
When a serial port is unbound while in use, uart_close() bypasses all of
this, as this is supposed to be done through uart_hangup() (invoked via
tty_vhangup() in uart_remove_one_port()).
However, uart_hangup() does not set the hardware's power state, leaving it
powered up. This may also lead to unbounded nesting counts in clock and
power management, depending on their internal implementation.
Make sure to power down the port in uart_hangup(), except when the port is
used as a serial console.
For serial consoles, this operation must be postponed until after the port
becomes completely unused. This case is not fixed yet, as it depends on a
(future) fix for the tty->count vs. port->count imbalance on failed
uart_open().
After this, the module clock used by the sh-sci driver is disabled on
unbind while the serial port is in use.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
The amba-pl011.c driver sets DMA burst size equal to FIFO trigger level.
If now exactly DMA burst size bytes are received, the DMAC will retrieve
them all and no Rx timeout interrupt will be generated. To fix that set
the burst size to half the FIFO trigger level.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
As far as I know the Timberdale chip was only used as a companion for
Intel Atom E600 series processors. As such, its drivers are only
useful on X86_32.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This driver, like several others, uses the upper bits of the character
to track both real and dummy state. Unfortunately it neglects to mask
these bits properly when passing the character data around. This means
neither break detection nor sysrq character handling work correctly.
This patch adds the requires masking and has been tested to confirm
that it correctly handles magic sysrq sequences on ST's B2020 board.
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This reverts commit 63e3ad3252,
since this not works as expected and produce runtime error:
BUG: sleeping function called from invalid context at drivers/tty/serial/clps711x.c:379
in_atomic(): 0, irqs_disabled(): 128, pid: 287, name: mount
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
If the serial_core ring buffer empties just as the tty layer receives
an XOFF, then start_tx will never be called when the tty layer
receives an XON as the serial_core ring buffer is empty. This will
possibly leave a few bytes trapped in the fifo for drivers that
disable the transmitter when flow controlled.
Signed-off-by: Seth Bollinger <sethb@digi.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Wolfram Sang pointed out that "efm32,$device" is non-standard. So use the
common scheme and prefix device with "efm32-". The old compatible string
is left in place until arch/arm/boot/dts/efm32* is fixed.
Reported-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Pull audit updates from Eric Paris.
* git://git.infradead.org/users/eparis/audit: (28 commits)
AUDIT: make audit_is_compat depend on CONFIG_AUDIT_COMPAT_GENERIC
audit: renumber AUDIT_FEATURE_CHANGE into the 1300 range
audit: do not cast audit_rule_data pointers pointlesly
AUDIT: Allow login in non-init namespaces
audit: define audit_is_compat in kernel internal header
kernel: Use RCU_INIT_POINTER(x, NULL) in audit.c
sched: declare pid_alive as inline
audit: use uapi/linux/audit.h for AUDIT_ARCH declarations
syscall_get_arch: remove useless function arguments
audit: remove stray newline from audit_log_execve_info() audit_panic() call
audit: remove stray newlines from audit_log_lost messages
audit: include subject in login records
audit: remove superfluous new- prefix in AUDIT_LOGIN messages
audit: allow user processes to log from another PID namespace
audit: anchor all pid references in the initial pid namespace
audit: convert PPIDs to the inital PID namespace.
pid: get pid_t ppid of task in init_pid_ns
audit: rename the misleading audit_get_context() to audit_take_context()
audit: Add generic compat syscall support
audit: Add CONFIG_HAVE_ARCH_AUDITSYSCALL
...
The firmware can notify us when new input data is available, so
let's make sure we wakeup the HVC thread in that case.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Pull ARM SoC driver changes from Arnd Bergmann:
"These changes are mostly for ARM specific device drivers that either
don't have an upstream maintainer, or that had the maintainer ask us
to pick up the changes to avoid conflicts.
A large chunk of this are clock drivers (bcm281xx, exynos, versatile,
shmobile), aside from that, reset controllers for STi as well as a
large rework of the Marvell Orion/EBU watchdog driver are notable"
* tag 'drivers-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (99 commits)
Revert "dts: socfpga: Add DTS entry for adding the stmmac glue layer for stmmac."
Revert "net: stmmac: Add SOCFPGA glue driver"
ARM: shmobile: r8a7791: Fix SCIFA3-5 clocks
ARM: STi: Add reset controller support to mach-sti Kconfig
drivers: reset: stih416: add softreset controller
drivers: reset: stih415: add softreset controller
drivers: reset: Reset controller driver for STiH416
drivers: reset: Reset controller driver for STiH415
drivers: reset: STi SoC system configuration reset controller support
dts: socfpga: Add sysmgr node so the gmac can use to reference
dts: socfpga: Add support for SD/MMC on the SOCFPGA platform
reset: Add optional resets and stubs
ARM: shmobile: r7s72100: fix bus clock calculation
Power: Reset: Generalize qnap-poweroff to work on Synology devices.
dts: socfpga: Update clock entry to support multiple parents
ARM: socfpga: Update socfpga_defconfig
dts: socfpga: Add DTS entry for adding the stmmac glue layer for stmmac.
net: stmmac: Add SOCFPGA glue driver
watchdog: orion_wdt: Use %pa to print 'phys_addr_t'
drivers: cci: Export CCI PMU revision
...
Pull ARM SoC cleanups from Arnd Bergmann:
"These cleanup patches are mainly move stuff around and should all be
harmless. They are mainly split out so that other branches can be
based on top to avoid conflicts.
Notable changes are:
- We finally remove all mach/timex.h, after CLOCK_TICK_RATE is no
longer used (Uwe Kleine-König)
- The Qualcomm MSM platform is split out into legacy mach-msm and
new-style mach-qcom, to allow easier maintainance of the new
hardware support without regressions (Kumar Gala)
- A rework of some of the Kconfig logic to simplify multiplatform
support (Rob Herring)
- Samsung Exynos gets closer to supporting multiplatform (Sachin
Kamat and others)
- mach-bcm3528 gets merged into mach-bcm (Stephen Warren)
- at91 gains some common clock framework support (Alexandre Belloni,
Jean-Jacques Hiblot and other French people)"
* tag 'cleanup-3.15' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (89 commits)
ARM: hisi: select HAVE_ARM_SCU only for SMP
ARM: efm32: allow uncompress debug output
ARM: prima2: build reset code standalone
ARM: at91: add PWM clock
ARM: at91: move sam9261 SoC to common clk
ARM: at91: prepare common clk transition for sam9261 SoC
ARM: at91: updated the at91_dt_defconfig with support for the ADS7846
ARM: at91: dt: sam9261: Device Tree support for the at91sam9261ek
ARM: at91: dt: defconfig: Added the sam9261 to the list of DT-enabled SOCs
ARM: at91: dt: Add at91sam9261 dt SoC support
ARM: at91: switch sam9rl to common clock framework
ARM: at91/dt: define main clk frequency of at91sam9rlek
ARM: at91/dt: define at91sam9rl clocks
ARM: at91: prepare common clk transition for sam9rl SoCs
ARM: at91: prepare sam9 dt boards transition to common clk
ARM: at91: dt: sam9rl: Device Tree for the at91sam9rlek
ARM: at91/defconfig: Add the sam9rl to the list of DT-enabled SOCs
ARM: at91: Add at91sam9rl DT SoC support
ARM: at91: prepare at91sam9rl DT transition
ARM: at91/defconfig: refresh at91sam9260_9g20_defconfig
...
Pull tty/serial driver update from Greg KH:
"Here's the big tty/serial driver update for 3.15-rc1.
Nothing major, a number of serial driver updates and a few tty core
fixes as well.
All have been in linux-next for a while"
* tag 'tty-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (71 commits)
tty/serial: omap: empty the RX FIFO at the end of half-duplex TX
tty/serial: omap: fix RX interrupt enable/disable in half-duplex TX
serial: sh-sci: Neaten dev_<level> uses
serial: sh-sci: Replace hardcoded 3 by UART_PM_STATE_OFF
serial: sh-sci: Add more register documentation
serial: sh-sci: Remove useless casts
serial: sh-sci: Replace printk() by pr_*()
serial_core: Avoid NULL pointer dereference in uart_close()
serial_core: Get a reference for port->tty in uart_remove_one_port()
serial: clps711x: Give a chance to perform useful tasks during wait loop
serial_core: Grammar s/ports/port's/
serial_core: Spelling s/contro/control/
serial: efm32: properly namespace location property
serial: max310x: Add missing #include <linux/uaccess.h>
synclink: fix info leak in ioctl
serial: 8250: Clean up the locking for -rt
serial: 8250_pci: change BayTrail default uartclk
serial: 8250_pci: more BayTrail error-free bauds
serial: sh-sci: Add missing call to uart_remove_one_port() in failure path
serial_core: Unregister console in uart_remove_one_port()
...
Thomas Pfaff
Doug Anderson
Loic Poulain
Manfred Schlaegl
Greg Kroah-Hartman
Guennadi Liakhovetski
Chen Tingjie
Jiri Slaby
Tony Lindgren
Geert Uytterhoeven
Jean Delvare
Daniel Thompson
Alexander Shiyan
Seth Bollinger
Uwe Kleine-König
Sanjay Singh Rawat
Linus Torvalds
Benjamin Herrenschmidt