3461 Commits

Author SHA1 Message Date
Robert Baldyga
736cd79f48 serial: samsung: fix DMA for FIFO smaller than cache line size
So far DMA mode were activated when only number of bytes to send was
equal or greater than min_dma_size. Due to requirement that DMA transaction
buffer should be aligned to cache line size, the excessive bytes were
written to FIFO before starting DMA transaction. The problem occurred
when FIFO size were smaller than cache alignment, because writing all
excessive bytes to FIFO would fail. It happened in DMA mode when PIO
interrupts disabled, which caused driver hung.

The solution is to test if buffer is alligned to cache line size before
activating DMA mode, and if it's not, running PIO mode to align buffer
and then starting DMA transaction. In PIO mode, when interrupts are
enabled, lack of space in FIFO isn't the problem, so buffer aligning
will always finish with success.

Cc: <stable@vger.kernel.org> # v3.18+
Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:24 -07:00
Marek Szyprowski
81ccb2a69f serial: samsung: fix DMA mode enter condition for small FIFO sizes
Due to some of serial ports can have FIFO size smaller than cache line
size, and because of need to align DMA buffer address to cache line size,
it's necessary to calculate minimum number of bytes for which we want
to start DMA transaction to be at least cache line size. The simplest
way to meet this requirement is to get maximum of cache line size and
FIFO size.

Cc: <stable@vger.kernel.org> # v3.18+
Reported-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:23 -07:00
Peter Hurley
9e31364fc3 serial: core: Remove tty port activate() and shutdown() methods
serial core does not use tty_port_open() or tty_port_close(); serial
core defines and extends it's own tty open() and close() methods
(uart_open() and uart_close(), respectively).

Remove the tty_port activate() and shutdown() initializations, and
the uart_port_activate() function, which is never called.

NB: uart_port_shutdown() is used by uart_close() => uart_shutdown()
call chain (but not via the tty_port methods).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:23 -07:00
Peter Hurley
6fb98fb303 serial: core: Use proper spinlock flavor in uart_close()
uart_close() runs in non-atomic context only; use
spin_lock/unlock_irq instead of saving the interrupt state (which
== on).

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:22 -07:00
Cyrille Pitchen
a649943522 tty/serial: at91: fix I/O accesses on RHR and THR for AVR32
This patch fixes I/O accesses on the Receiver Holding Register and on the
Transmitter Holding Register. Indeed AVR32 can only perform 32bit I/O
accesses on registers: using 8bit I/O accesses would read or write garbage
data.

Fixes: commit b5199d468177 ("tty/serial: at91: add support to FIFOs")
Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Tested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:22 -07:00
Geert Uytterhoeven
b737eeb09e serial: Allow compile test of GPIO consumers if !GPIOLIB
The GPIO subsystem provides dummy GPIO consumer functions if GPIOLIB is
not enabled. Hence drivers that depend on GPIOLIB, but use GPIO consumer
functionality only, can still be compiled if GPIOLIB is not enabled.

Relax the dependency on GPIOLIB if COMPILE_TEST is enabled, where
appropriate.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:21 -07:00
Qipeng Zha
0a6c301a2d serial: 8250: Auto CTS control by HW if AFE enabled
According to DesignWare 8250 spec, if auto flow control
mode is enabled, a change in CTS does not cause an interrupt,
so sw-assisted CTS flow control mode will not work properly.

There reported an GPS firmware download failure issue, and we
verified the root cause is, the default sw-assisted CTS flow
control mode can not work properly since no interrupt when got
CTS signal.

This patch is to enable auto CTS mode by defaut if CRTSCTS
is enable for DesignWare 8250 controller.

Signed-off-by: Huiquan Zhong <huiquan.zhong@intel.com>
Signed-off-by: Qipeng Zha <qipeng.zha@intel.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:21 -07:00
Uwe Kleine-König
7d07ada047 serial: mpc52xx: let tx_empty callback return either 0 or TIOCSER_TEMT
Documenation/serial/driver requests that the tx_empty callback should
return 0 if there are still chars in the fifo or shifter or TIOCSER_TEMT
(0x01) if no character is pending to be sent.

Fix the mpc52xx serial driver to not return MPC52xx_PSC_SR_TXEMP (i.e.
0x0800) but TIOCSER_TEMT as documented.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:20 -07:00
Niklas Cassel
7b9c5162c1 serial: etraxfs-uart: use mctrl_gpio helpers for handling modem signals
In order to use the mctrl_gpio helpers, we change the DT bindings:
ri-gpios renamed to rng-gpios. cd-gpios renamed to dcd-gpios.
However, no in-tree dts/dtsi specifies these, so no worries.

Signed-off-by: Niklas Cassel <nks@flawful.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:20 -07:00
Niklas Cassel
9625734ff7 serial: etraxfs-uart: remove empty functions
Implementing enable_ms is optional by serial_core.
check_modem_status is just an empty local function.

Signed-off-by: Niklas Cassel <nks@flawful.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-04 22:07:19 -07:00
Shenwei Wang
90bb6bd385 Serial: imx: add dev_pm_ops to support suspend to ram/disk
When system goes into low power states like SUSPEND_MEM and
HIBERNATION, the hardware IP block may be powered off to reduce
the power consumption. This power down may cause problems on
some imx platforms, because the hardware settings are reset to
its power on default values which may differ from the ones when
it power off. This patch added the dev_pm_ops and implemented
two callbacks: suspend_noirq and resume_noirq, which will save
the necessory hardware parameters right before power down and
recover them before system uses the hardware.

Because added the dev_pm_ops, the old suspend/resume callbacks
under platform_driver will not be called any more. Changed their
prototypes and moved those two callbacks into dev_pm_ops too.

Signed-off-by: Shenwei Wang <shenwei.wang@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-03 15:51:19 -07:00
Masahiro Yamada
e70e69bf20 serial: 8250_uniphier: call clk_disable_unprepare() on failure path
If serial8250_register_8250_port() fails, disable and unprepare the
clock before exiting.

Fixes: 1a8d2903cb6a ("serial: 8250_uniphier: add UniPhier serial driver")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-03 15:51:19 -07:00
Peter Hung
fecf27a373 serial: 8250_pci: add RS485 for F81504/508/512
Add RS485 control for Fintek F81504/508/512

F81504/508/512 can control their RTS with H/W mode.
PCI configuration space for each port is 0x40 + idx * 8 + 7.

When it set with 0x01, it's configured with RS232 mode.
RTS is controlled by MCR.

When it set with 0x11, it's configured with RS485 mode.
RTS is controlled by H/W, RTS low with idle & RX, high with TX.

When it set with 0x31, it's configured with RS485 mode.
RTS is controlled by H/W, RTS high with idle & RX, low with TX.

We will force 0x01 on pci_fintek_setup().

Signed-off-by: Peter Hung <hpeter+linux_kernel@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-03 15:40:29 -07:00
Richard Watts
a3a10ce342 Avoid usb reset crashes by making tty_io cdevs truly dynamic
Avoid usb reset crashes by making tty_io cdevs truly dynamic

Signed-off-by: Richard Watts <rrw@kynesim.co.uk>
Reported-by: Duncan Mackintosh <DMackintosh@cbnl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-08-03 15:24:43 -07:00
Fabio Estevam
458e2c82c5 Revert "tty: serial: imx.c: Reset UART before activating interrupts"
This reverts commit e95044ba4fee93f5ea8a1a24b2d921e148503833.

Commit e95044ba4fee93 ("tty: serial: imx.c: Reset UART before activating
interrupts") terribly messes up with the console on mx6 boards, so
let's revert it.

Reported-by: kernelci.org bot <bot@kernelci.org>
Cc: David Jander <david@protonic.nl>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-27 11:26:56 -07:00
Greg Kroah-Hartman
92311e46ec Merge 4.2-rc4 into tty-next
Other serial driver work wants to build on patches now in 4.2-rc4 so
merge the branch so this can properly happen.

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-27 11:12:39 -07:00
Peter Hurley
d684779335 pty: Add debug message for ptmx open
Opens of /dev/ptmx don't use tty_open() so debug messages are
not printed for those opens; print a debug message with the
open count (which must always be 1) if TTY_DEBUG_HANGUP is defined.

NB: Each tty core source file undefs support for debug messages.
The relevant source file must be patched/edited to enable these
messages.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:37:32 -07:00
Peter Hurley
fb6edc9115 tty: core: Improve ldisc debug messages
Add debug messages for ldisc open and close, and remove
"closing ldisc" message from tty_ldisc_release(), because a
close message is now printed for both ldiscs; always print ldisc
pointer first so ldisc changes are easier to identify.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:37:31 -07:00
Peter Hurley
ff8339dc16 tty: Replace inline #ifdef TTY_DEBUG_WAIT_UNTIL_SENT
Add tty_debug_wait_until_sent() macro which uses tty_debug() to print
the debug message; remove inlined #ifdef.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:37:31 -07:00
Peter Hurley
0a6adc131c tty: Use tty_debug() for tty_ldisc_debug()
Replace tty_ldisc_debug() macro definition; substitute with equivalent
tty_debug() invocation.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:37:31 -07:00
Peter Hurley
accff793af tty: Replace #ifdef TTY_DEBUG_HANGUP with tty_debug_hangup()
Add tty_debug_hangup() macro which uses tty_debug to print the
debug message; remove inlined #ifdefs.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:37:31 -07:00
Peter Hurley
e2dfa3d387 tty: core: Add tty_debug() for printk(KERN_DEBUG) messages
Introduce tty_debug() macro to output uniform debug information for
tty core debug messages (function name and tty name).

Note: printk(KERN_DEBUG) is retained here over pr_debug() since
messages can be enabled in non-DEBUG builds.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:37:31 -07:00
Peter Hurley
3a6b02dc1f tty: core: Improve debug message content
Output the function name, tty name, and invariant failure (if applicable).
Add the tty count to the tty_open() message. Fix the disassociate_ctty()
message, which printed the NULL pointer and the wrong message.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:31:29 -07:00
Paul Gortmaker
4fef53518f drivers/tty: make serial/sunhv.c driver explicitly non-modular
The Kconfig for this driver is currently:

config SERIAL_SUNHV
        bool "Sun4v Hypervisor Console support"

...meaning that it currently is not being built as a module by
anyone.  Lets remove the modular and unused code here, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

We don't swap module.h for init.h since this file has init.h already.

We leave some tags like MODULE_LICENSE for documentation purposes, and
for the "git blame" value.  Also note that MODULE_DEVICE_TABLE is a
no-op for non-modular code, so we remove that too.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: sparclinux@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:27:41 -07:00
Paul Gortmaker
37db223467 drivers/tty: make serial/suncore.c driver explicitly non-modular
The Kconfig for this driver is currently:

config SERIAL_SUNCORE
        bool

...meaning that it currently is not being built as a module by
anyone.  Lets remove the modular and unused code here, so that
when reading the driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

We don't swap module.h for init.h since this file has init.h already.

We leave some tags like MODULE_LICENSE for documentation purposes, and
for the "git blame" value.

Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: sparclinux@vger.kernel.org
Cc: linux-serial@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:27:41 -07:00
Paul Gortmaker
1106d2dbab drivers/tty: make serial/lantic.c driver explicitly non-modular
The Kconfig for this option is currently:

config SERIAL_LANTIQ
    bool "Lantiq serial driver"

...meaning that it currently is not being built as a module by anyone.
Lets remove the couple traces of modularity, so that when reading the
driver there is no doubt it is builtin-only.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

We delete the MODULE_DESCRIPTION and LICENSE tags since they are
not adding any new information above and beyond what is at the top
of the file.  Also note that MODULE_DEVICE_TABLE is a no-op for
non-modular code, so we remove that as well.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:27:41 -07:00
Paul Gortmaker
4e62794bd8 drivers/tty: make serial/sn_console.c driver explicitly non-modular
The Kconfig for this option is currently:

config SERIAL_SGI_L1_CONSOLE
    bool "SGI Altix L1 serial console support"

...meaning that it currently is not being built as a module by anyone.
Lets remove the orphaned module code, so that when reading the
driver there is no doubt it is builtin-only.  We could consider
making it tristate, but the above bool has been there since before
the start of git history, which isn't all that surprising, since
consoles are typically critical to have at early boot.  So adding
tristate is really of no value here.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-serial@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:27:41 -07:00
Javier Martinez Canillas
97d49add8b serial: samsung: Remove redundant DEBUG_LL check
Commit 84f57d9e3685 ("tty: serial/samsung: fix modular build") fixed
build issues when the driver was built as a module. One of those was
that printascii is only accessible when the driver is built-in.

But there is no need to check for defined(CONFIG_DEBUG_LL) since the
SERIAL_SAMSUNG_DEBUG Kconfig symbol already depends on DEBUG_LL.

Signed-off-by: Javier Martinez Canillas <javier@osg.samsung.com>
Reviewed-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Acked-by: Kukjin Kim <kgene@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:27:41 -07:00
Peter Hurley
af5554f957 tty: buffers: Move hidden buffer index advance into outer loop
The advance of the 'read' buffer index belongs in the outer
flip buffer consume loop, with the other buffer index arithmetic.

No functional change.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:23:56 -07:00
Peter Hurley
069f38b498 tty: Replace smp_rmb/smp_wmb with smp_load_acquire/smp_store_release
Clarify flip buffer producer/consumer operation; the use of
smp_load_acquire() and smp_store_release() more clearly indicates
which memory access requires a barrier.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:23:56 -07:00
Peter Hurley
61e86cc90a tty: vt: Fix !TASK_RUNNING diagnostic warning from paste_selection()
Pasting text with gpm on a VC produced warning [1]. Reset task state
to TASK_RUNNING in the paste_selection() loop, if the loop did not
sleep.

[1]
WARNING: CPU: 6 PID: 1960 at /home/peter/src/kernels/mainline/kernel/sched/core.c:7286 __might_sleep+0x7f/0x90()
do not call blocking ops when !TASK_RUNNING; state=1 set at [<ffffffff8151805e>] paste_selection+0x9e/0x1a0
Modules linked in: btrfs xor raid6_pq ufs qnx4 hfsplus hfs minix ntfs msdos jfs xfs libcrc32c .....
CPU: 6 PID: 1960 Comm: gpm Not tainted 4.1.0-rc7+tty-xeon+debug #rc7+tty
Hardware name: Dell Inc. Precision WorkStation T5400  /0RW203, BIOS A11 04/30/2012
 ffffffff81c9c0a0 ffff8802b0fd3ac8 ffffffff8185778a 0000000000000001
 ffff8802b0fd3b18 ffff8802b0fd3b08 ffffffff8108039a ffffffff82ae8510
 ffffffff81c9ce00 0000000000000015 0000000000000000 0000000000000000
Call Trace:
 [<ffffffff8185778a>] dump_stack+0x4f/0x7b
 [<ffffffff8108039a>] warn_slowpath_common+0x8a/0xc0
 [<ffffffff81080416>] warn_slowpath_fmt+0x46/0x50
 [<ffffffff810ddced>] ? __lock_acquire+0xe2d/0x13a0
 [<ffffffff8151805e>] ? paste_selection+0x9e/0x1a0
 [<ffffffff8151805e>] ? paste_selection+0x9e/0x1a0
 [<ffffffff810ad4ff>] __might_sleep+0x7f/0x90
 [<ffffffff8185f76a>] down_read+0x2a/0xa0
 [<ffffffff810bb1d8>] ? sched_clock_cpu+0xb8/0xe0
 [<ffffffff8150d1dc>] n_tty_receive_buf_common+0x4c/0xba0
 [<ffffffff810dc875>] ? mark_held_locks+0x75/0xa0
 [<ffffffff81861c95>] ? _raw_spin_unlock_irqrestore+0x65/0x80
 [<ffffffff810b49a1>] ? get_parent_ip+0x11/0x50
 [<ffffffff8150dd44>] n_tty_receive_buf2+0x14/0x20
 [<ffffffff81518117>] paste_selection+0x157/0x1a0
 [<ffffffff810b77b0>] ? wake_up_state+0x20/0x20
 [<ffffffff815203f8>] tioclinux+0xb8/0x2c0
 [<ffffffff81515bfe>] vt_ioctl+0xaee/0x11a0
 [<ffffffff810baf75>] ? sched_clock_local+0x25/0x90
 [<ffffffff810bbe11>] ? vtime_account_user+0x91/0xa0
 [<ffffffff8150810c>] tty_ioctl+0x20c/0xe20
 [<ffffffff810bbe11>] ? vtime_account_user+0x91/0xa0
 [<ffffffff810b49a1>] ? get_parent_ip+0x11/0x50
 [<ffffffff810b4a69>] ? preempt_count_sub+0x49/0x50
 [<ffffffff811ab71c>] ? context_tracking_exit+0x5c/0x290
 [<ffffffff811ab71c>] ? context_tracking_exit+0x5c/0x290
 [<ffffffff81248b98>] do_vfs_ioctl+0x318/0x570
 [<ffffffff810dca8d>] ? trace_hardirqs_on+0xd/0x10
 [<ffffffff810dc9b5>] ? trace_hardirqs_on_caller+0x115/0x1e0
 [<ffffffff81254acc>] ? __fget_light+0x6c/0xa0
 [<ffffffff81248e71>] SyS_ioctl+0x81/0xa0
 [<ffffffff81862832>] system_call_fastpath+0x16/0x7a

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:08:29 -07:00
Peter Hurley
e144c58cad serial: core: Fix crashes while echoing when closing
While closing, new rx data may be received after the input buffers
have been flushed but before stop_rx() halts receiving [1]. The
new data might not be processed by flush_to_ldisc() until after
uart_shutdown() and normal input processing is re-enabled (ie.,
tty->closing = 0). The race is outlined below:

CPU 0                         | CPU 1
                              |
uart_close()                  |
   tty_port_close_start()     |
      tty->closing = 1        |
      tty_ldisc_flush()       |
                              | => IRQ
                              |   while (LSR & data ready)
                              |      uart_insert_char()
                              |   tty_flip_buffer_push()
                              | <= EOI
   stop_rx()                  |   .
   uart_shutdown()            |   .
      free xmit.buf           |   .
   tty_port_tty_set(NULL)     |   .
   tty->closing = 0           |   .
                              | flush_to_ldisc()
                              |   n_tty_receive_buf_common()
                              |      __receive_buf()
                              |         ...
                              |         commit_echoes()
                              |            uart_flush_chars()
                              |               __uart_start()
                              | ** OOPS on port.tty deref **
   tty_ldisc_flush()          |

Input processing must be prevented from echoing (tty->closing = 1)
until _after_ the input buffers have been flushed again at the end
of uart_close().

[1] In fact, some input may actually be buffered _after_ stop_rx()
since the rx interrupt may have already triggered but not yet been
handled when stop_rx() disables rx interrupts.

Fixes: 2e758910832d ("serial: core: Flush ldisc after dropping port
mutex in uart_close()")
Reported-by: Robert Elliott <elliott@hp.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:08:28 -07:00
Alexander Stein
e5eb517dd8 serial/uuc_uart: Support higher bitrates than 115200 Bit/s
The maximum bitrate supported depends on the clock rate used in BRG.
This is stored in port.uartclk during probe. Respecting the 16x
oversampling higher bitrates can be supported.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:05:00 -07:00
Krzysztof Kozlowski
7e8af24fbe tty: serial: Drop owner assignment from i2c_driver
i2c_driver does not need to set an owner because i2c_register_driver()
will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:04:59 -07:00
Krzysztof Kozlowski
3bb2ccd0d1 tty: serial: Drop owner assignment from platform_driver
platform_driver does not need to set an owner because
platform_driver_register() will set it.

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:04:59 -07:00
Cyrille Pitchen
5f258b3e3d tty/serial: at91: use 32bit writes into TX FIFO when DMA is enabled
For now this improvement is only used with TX DMA transfers. The data
width must be set properly when configuring the DMA controller. Also
the FIFO configuration must be set to match the DMA transfer data
width:
TXRDYM (Transmitter Ready Mode) and RXRDYM (Receiver Ready Mode) must
be set into the FIFO Mode Register. These values are used by the
USART to trigger the DMA controller. In single data mode they are not
used and should be reset to 0.
So the TXRDYM bits are changed to FOUR_DATA; then USART triggers the
DMA controller when at least 4 data can be written into the TX FIFO
througth the THR. On the other hand the RXRDYM bits are left unchanged
to ONE_DATA.

Atmel eXtended DMA controller allows us to set a different data width
for each part of a scatter-gather transfer. So when calling
dmaengine_slave_config() to configure the TX path, we just need to set
dst_addr_width to the maximum data width. Then DMA writes into THR are
split into up to two parts. The first part carries the first data to
be sent and has a length equal to the greatest multiple of 4 (bytes)
lower than or equal to the total length of the TX DMA transfer. The
second part carries the trailing data (up to 3 bytes). The first part
is written by the DMA into THR using 32 bit accesses, whereas 8bit
accesses are used for the second part.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:00:43 -07:00
Cyrille Pitchen
b5199d4681 tty/serial: at91: add support to FIFOs
Depending on the hardware, TX and RX FIFOs may be available. The RX
FIFO can avoid receive overruns, especially when DMA transfers are
not used to read data from the Receive Holding Register. For heavy
system load, The CPU is likely not be able to fetch data fast enough
from the RHR.

In addition, the RX FIFO can supersede the DMA/PDC to control the RTS
line when the Hardware Handshaking mode is enabled. Two thresholds
are to be set for that purpose:
- When the number of data in the RX FIFO crosses and becomes lower
  than or equal to the low threshold, the RTS line is set to low
  level: the remote peer is requested to send data.
- When the number of data in the RX FIFO crosses and becomes greater
  than or equal to the high threshold, the RTS line is set to high
  level: the remote peer should stop sending new data.
- low threshold <= high threshold
Once these two thresholds are set properly, this new feature is
enabled by setting the FIFO RTS Control bit of the FIFO Mode Register.

FIFOs also introduce a new multiple data mode: the USART works either
in multiple data mode or in single data (legacy) mode.

If MODE9 bit is set into the Mode Register or if USMODE is set to
either LIN_MASTER, LIN_SLAVE or LON_MODE, FIFOs operate in single
data mode. Otherwise, they operate in multiple data mode.

In this new multiple data mode, accesses to the Receive Holding
Register or Transmit Holding Register slightly change.

Since this driver implements neither the 9bit data feature (MODE9 bit
set into the Mode Register) nor LIN modes, the USART works in
multiple data mode whenever FIFOs are available and enabled. We also
assume that data are 8bit wide.

In single data mode, 32bit access CAN be used to read a single data
from RHR or write a single data into THR.
However in multiple data mode, a 32bit access to RHR now allows us to
read four consecutive data from RX FIFO. Also a 32bit access to THR
now allows to write four consecutive data into TX FIFO. So we MUST
use 8bit access whenever only one data have to be read/written at a
time.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:00:42 -07:00
Cyrille Pitchen
4e7decdaaa tty/serial: at91: remove bunch of macros to access UART registers
This patch replaces the UART_PUT_*, resp. UART_GET_*, macros by
atmel_uart_writel(), resp. atmel_uart_readl(), inline function calls.

Signed-off-by: Cyrille Pitchen <cyrille.pitchen@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 18:00:42 -07:00
Patrick Donnelly
6719693ca2 tty: add missing rcu_read_lock for task_pgrp
task_pgrp requires an rcu or tasklist lock to be obtained if the returned pid
is to be dereferenced, which kill_pgrp does. Obtain an RCU lock for the
duration of use.

Signed-off-by: Patrick Donnelly <batrick@batbytes.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:56:38 -07:00
Joerg Roedel
da891641b6 serial: 8250: Do XR17V35X specific wakeup in serial8250_do_startup
The XR17V35X UART needs the ECB bit set in its XR_EFR
register to enable access to IER [7:5], ISR [5:4], FCR[5:4],
MCR[7:5], and MSR [7:0].

Also reset the IER register to mask interrupts after access
to all bits of this register has been enabled.

This makes my 8-port XR17V35X working with the in-kernel
serial driver.

Cc: Joe Schultz <jschultz@xes-inc.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Reviewed-by: Michael Welling <mwelling@ieee.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:49:42 -07:00
Peter Hurley
ee3ad90be5 serial: 8250: Defer interrupt enable until fifos enabled
An already-active sender can swamp the interrupt handler with
"too much work" if the rx interrupts are enabled when the fifo is
disabled and operating in single-byte mode.

Defer rx and line status interrupt enable until after the fifos
are enabled in set_termios(), but at least initialize the shadow
IER value with the interrupts which will be enabled.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:48:43 -07:00
Vineet Gupta
f3fb7ef398 tty/early: make serial8250_early_{in,out} static again
Commit ed71871bed719 ("tty/8250_early: Turn serial_in/serial_out into
weak symbols") made these routines weak to allow platform specific
Big endian override

However recent updates to core, specifically ebc5e20082 ("serial:
of_serial: Support big-endian register accesses") and 6e63be3fee14
("serial: earlycon: Add support for big-endian MMIO accesses") means
that round about way to overide the early serial accessors is no longer
needed.

Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Rob Herring <robh@kernel.org>
Cc: Kevin Cernekee <cernekee@gmail.com>
Acked-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:43:30 -07:00
Peter Hurley
b6830f6df8 serial: 8250: Split base port operations from universal driver
Refactor base port operations into new file; 8250_port.c.

Legacy irq handling, RSA port support, port storage for universal
driver, driver definition, module parameters and linkage remain in
8250_core.c

The source file split and resulting modules is diagrammed below:

  8250_core.c ====>   8250_core.c __
              \                     \
               \                     +-- 8250.ko (alias 8250_core)
                \     8250_pnp.c  __/     (universal driver)
                 \
                  =>  8250_port.c __
                                    \
                                     +-- 8250_base.ko
                      8250_dma.c  __/     (port operations)

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:43:01 -07:00
David Jander
907eda32a3 Revert "serial: imx: initialized DMA w/o HW flow enabled"
This reverts commit 068500e08dc87ea9a453cc4a500cf3ab28d0f936.

According to some tests, SDMA support is broken at least for i.MX6 without
HW flow control. Different forms of data-corruption appear either with
the ROM firmware for the SDMA controller as well as when loading Freescale
provided SDMA firmware versions 1.1 or 3.1.

Signed-off-by: David Jander <david@protonic.nl>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:40:14 -07:00
David Jander
e95044ba4f tty: serial: imx.c: Reset UART before activating interrupts
If the UART has been in use before this driver was loaded, IRQs might be
active and get fired as soon as we set the handler, which will crash
in the spin_lock_irqsave(&sport->port.lock, flags) because port.lock is
not initialized until the port is added at the end of probe.

Signed-off-by: David Jander <david@protonic.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:39:08 -07:00
Manfred Schlaegl
e9b5a9825f serial: imx: reduce irq-latency after rx overflow
To prevent problems with interrupt latency, and due to the fact, that
the error will be counted anyway (icount.overrun), the dev_err is simply
removed.

Background:
If an rx-fifo overflow occurs a dev_err message was called in interrupt
context. Since dev_err messages are written to console in a synchronous way
(unbuffered), and console may be a serial terminal, this leads to a
highly increased interrupt-latency (several milliseconds).
As a result of the high latency more rx-fifo overflows will happen, and
therefore a feedback loop of errors is created.

Signed-off-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Acked-By: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:37:54 -07:00
Manfred Schlaegl
9b28993261 serial: imx: count tty buffer overruns
As can be seen in function uart_insert_char (serial_core) the element
buf_overrun of struct uart_icount is used to count overruns of
tty-buffer.
Added support for counting of overruns in imx driver analogue to
serial_core.

Signed-off-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:37:53 -07:00
Fabio Estevam
8a61f0c70a serial: imx: Disable irqs before requesting them
Disable interrupts before requesting them in order to fix a kernel oops
after lauching a kernel via kexec.

Tested on a imx6sl-evk board.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:37:53 -07:00
Ricardo Ribalda Delgado
1eacbfb06d serial/uartlite: Let it build on any arch with IOMEM
Being a soft core, it can be located not only on PPC or Microblaze
platforms.

Since the driver already does endianness detection we only need to
change the Kconfig to use it in other arches.

This is also done in other softcores as xilinx-spi.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:37:53 -07:00
Maxime Coquelin
6b596a8341 serial: stm32-usart: Fix SysRq support
SysRq support activation depends on CONFIG_SERIAL_STM32_USART_CONSOLE, but
this config flag does not exists.

This patch fix this by depending on the valid config flag, which is
SERIAL_STM32_CONSOLE.

Reported-by: Andreas Ruprecht <andreas.ruprecht@fau.de>
Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-07-23 17:37:53 -07:00