Commit Graph

1874 Commits

Author SHA1 Message Date
Sebastian Andrzej Siewior
77285243a6 tty: serial: 8250: omap: add custom irq handling
We have (or will have) custom DMA callbacks in the omap driver due to
the different behaviour in the RX and TX case. To make this work
we need a few changes in the IRQ handler to invoke the rx_handler again
after the "manual" mode or retry the tx_handler again before falling
back to the manual mode.

Heikki didn't want to see the extra hacks in the generic / default irq
handler and Peter wasn't too happy about an OMAP-only IRQ handler. The
way I planned it is to use this extra IRQ routine only in DMA case. If
Peter dislike this approach then I hope Heikki doesn't block changes in
the default IRQ handler :)

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:13:34 -08:00
Sebastian Andrzej Siewior
0e31c8d173 tty: serial: 8250_omap: add custom DMA-RX callback
The omap needs a DMA request pending right away. If it is
enqueued once the bytes are in the FIFO then nothing will happen
and the FIFO will be later purged via RX-timeout interrupt.
This patch enqueues RX-DMA request on completion but not if it
was aborted on error. The first enqueue will happen in the driver
in startup.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:10:07 -08:00
Sebastian Andrzej Siewior
31a171328e tty: serial: 8250_omap: add custom DMA-TX callback
This patch provides mostly a copy of serial8250_tx_dma() +
__dma_tx_complete() with the following extensions:

- DMA bug
  At least on AM335x the following problem exists: Even if the TX FIFO is
  empty and a TX transfer is programmed (and started) the UART does not
  trigger the DMA transfer.
  After $TRESHOLD number of bytes have been written to the FIFO manually the
  UART reevaluates the whole situation and decides that now there is enough
  room in the FIFO and so the transfer begins.
  This problem has not been seen on DRA7 or beagle board xm (OMAP3). I am not
  sure if this is UART-IP core specific or DMA engine.

  The workaround is to use a threshold of one byte, program the DMA
  transfer minus one byte and then to put the first byte into the FIFO to
  kick start the transfer.

- support for runtime PM
  RPM is enabled on start_tx(). We can't disable RPM on DMA complete callback
  because there is still data in the FIFO which is being sent. We have to wait
  until the FIFO is empty before we disable it.
  For this to happen we fake a TX sent error and enable THRI. Once the
  FIFO is empty we receive an interrupt and since the TTY-buffer is still
  empty we "put RPM" via __stop_tx(). Should it been filed then in the
  start_tx() path we should program the DMA transfer and remove the error
  flag and the THRI bit.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:10:07 -08:00
Sebastian Andrzej Siewior
f1a297bb04 tty: serial: 8250: allow to use custom DMA implementation
The OMAP has a few corner cases where it needs a share of kindness of
affection to do the right thing. Heikki Krogerus suggested that instead
adding the quirks into the default DMA implementation, OMAP could get
its own copy of the function. And Alan suggested the same thing so here
we go.

This patch provides callbacks for custom TX/RX DMA implementation. If
there are not setup / used, then the default (current) implementation is
used.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:07:48 -08:00
Sebastian Andrzej Siewior
0fcb7901f9 tty: serial: 8250_dma: keep own book keeping about RX transfers
After dmaengine_terminate_all() has been invoked then both DMA drivers
(edma and omap-dma) do not invoke dma_cookie_complete() to mark the
transfer as complete. This dma_cookie_complete() is performed by the
Synopsys DesignWare driver which is probably the only one that is used
by omap8250-dma and hence don't see following problem…
…which is that once a RX transfer has been terminated then following
query of channel status reports DMA_IN_PROGRESS (again: the actual
transfer has been canceled, there is nothing going on anymore).

This means that serial8250_rx_dma() never enqueues another DMA transfer
because it (wrongly) assumes that there is a transer already pending.

Vinod Koul refuses to accept a patch which adds this
dma_cookie_complete() to both drivers and so dmaengine_tx_status() would
report DMA_COMPLETE instead (and behave like the Synopsys DesignWare
driver already does). He argues that I am not allowed to use the cookie
to query the status and that the driver already cleaned everything up after
the invokation of dmaengine_terminate_all().

To end this I add a bookkeeping whether or not a RX-transfer has been
started to the 8250-dma code. It has already been done for the TX side.
*Now* we learn about the RX status based on our bookkeeping and don't
need dmaengine_tx_status() for this anymore.

Cc: vinod.koul@intel.com
Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:05:13 -08:00
Sebastian Andrzej Siewior
b220282156 tty: serial: 8250_dma: handle error on TX submit
Right now it is possible that serial8250_tx_dma() fails and returns
-EBUSY. The caller (serial8250_start_tx()) will then enable
UART_IER_THRI which will generate an interrupt once the TX FIFO is
empty.
In serial8250_handle_irq() nothing will happen because up->dma is set
and so serial8250_tx_chars() won't be invoked. We end up with plenty of
interrupts and some "too much work for irq" output.

This patch introduces dma_tx_err in struct uart_8250_port to signal that
the last invocation of serial8250_tx_dma() failed so we can fill the TX
FIFO manually. Should the next invocation of serial8250_start_tx()
succeed then the dma_tx_err flag along with the THRI bit is removed and
DMA only usage may continue.

Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:05:13 -08:00
Sebastian Andrzej Siewior
61929cf016 tty: serial: Add 8250-core based omap driver
This patch provides a 8250-core based UART driver for the internal OMAP
UART. The long term goal is to provide the same functionality as the
current OMAP uart driver and DMA support.
I tried to merge omap-serial code together with the 8250-core code.
There should should be hardly a noticable difference. The trigger levels
are different compared to omap-serial:
- omap serial
  TX: Interrupt comes after TX FIFO has room for 16 bytes.
      TX of 4096 bytes in one go results in 256 interrupts

  RX: Interrupt comes after there is on byte in the FIFO.
      RX of 4096 bytes results in 4096 interrupts.

- this driver
  TX: Interrupt comes once the TX FIFO is empty.
      TX of 4096 bytes results in 65 interrupts. That means there will
      be gaps on the line while the driver reloads the FIFO.

  RX: Interrupt comes once there are 48 bytes in the FIFO or less over
      "longer" time frame. We have
          1 / 11520 * 10^3 * 16 => 1.38… ms
      1.38ms to react and purge the FIFO on 115200,8N1. Since the other
      driver fired after each byte it had ~5.47ms time to react. This
      _may_ cause problems if one relies on no missing bytes and has no
      flow control. On the other hand we get only 85 interrupts for the
      same amount of data.

It has been only tested as console UART on am335x-evm, dra7-evm and
beagle bone. I also did some longer raw-transfers to meassure the load.

The device name is ttyS based instead of ttyO. If a ttyO based node name
is required please ask udev for it. If both driver are activated (this
and omap-serial) then this serial driver will take control over the
device due to the link order

v9…v10:
	- Tony noticed that omap3 won't show anything after waking up
	  from core off. In v9 I reworked the register restore and set
	  IER to 0 by accident. This went unnoticed because start_tx
	  usually sets ier (either due to DMA bug or due to TX-complete
	  IRQ).
	- dropped EFR and SLEEP from capabilities. We do have both but
	  nobody should touch it. We already handle SLEEP ourself.
	- make the private copy of the registers (like EFR) u8 instead
	  u32
	- drop MDR1 & DL[ML] reset in restore registers. Does not look
	  required it is set to the required value later.
	- update MDR1 & SCR only if changed.
	- set MDR1 as the last thing. The errata says that we should
	  setup everything before MDR1 set.
	- avoid div by 0 in omap_8250_get_divisor() if baud rate gets
	  very large (Frans Klaver fixed the same thing omap-serial)
	- drop "is in early stage" from Kconfig.
v8…v9:
	- less on a file seems to hang the am335x after a while. I
	  believe I introduce this bug a while ago since I can reproduce
	  this prior to v8. Fixed by redoing the omap8250_restore_regs()
v7…v8:
	- redo the register write. There is now one function for that
	  which is used from set_termios() and runtime-resume.
	- drop PORT_OMAP_16750 and move the setup to the omap file. We
	  have our own set termios function anyway (Heikki Krogerus)
	- use MEM instead of MEM32. TRM of AM/DM37x says that 32bit
	  access on THR might result in data abort. We only need 32bit
	  access in the errata function which is before we use 8250's
	  read function so it doesn't matter.
v4…v7:
	- change trigger levels after some tests with raw transfers.
v3…v4:
	- drop RS485 support
	- wire up ->throttle / ->unthrottle
v2…v3:
	- wire up startup & shutdown for wakeup-irq handling.
	- RS485 handling (well the core does).

v1…v2:
	- added runtime PM. Could somebody could please double check
	  this?
	- added omap_8250_set_termios()

Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:05:13 -08:00
Sebastian Andrzej Siewior
f31b5d27be tty: serial: 8250: make serial8250_console_setup() non _init
if I boot with console=ttyS0 and the omap driver is module I end up with

| console [ttyS0] disabled
| omap8250 44e09000.serial: ttyS0 at MMIO 0x44e09000 (irq = 88, base_baud = 3000000) is a 8250
| Unable to handle kernel paging request at virtual address c07a9de0
| Modules linked in: 8250_omap(+)
| CPU: 0 PID: 908 Comm: modprobe Not tainted 3.17.0-rc5+ #1593
| PC is at serial8250_console_setup+0x0/0xc8
| LR is at register_console+0x13c/0x3a4
| [<c0078788>] (register_console) from [<c02d0340>] (uart_add_one_port+0x3cc/0x420)
| [<c02d0340>] (uart_add_one_port) from [<c02d38a4>] (serial8250_register_8250_port+0x298/0x39c)
| [<c02d38a4>] (serial8250_register_8250_port) from [<bf006274>] (omap8250_probe+0x218/0x3dc [8250_omap])
| [<bf006274>] (omap8250_probe [8250_omap]) from [<c02e3424>] (platform_drv_probe+0x2c/0x5c)
| [<c02e3424>] (platform_drv_probe) from [<c02e1eac>] (driver_probe_device+0x104/0x228)
…
| [<c009fa48>] (SyS_init_module) from [<c000e6e0>] (ret_fast_syscall+0x0/0x30)
| Code: 7823603b f8314620 051b3013 491ed416 (44792204)

because serial8250_console_setup() is already gone.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:02:59 -08:00
Sebastian Andrzej Siewior
6a529abae8 tty: serial: 8250: Fix wording in runtime-PM comments
Frans reworded the two comments with better English for better
understanding. His review hit the mailing list after the patch got
applied so here is an incremental update.

Reported-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 19:02:59 -08:00
Janusz Uzycki
914d3b17e9 serial: mxs-auart: add sysrq support
When using mxs-auart based console, sometime we need the sysrq function
to help debugging kernel. The sysrq code is basically there,
this patch just simply enable it.

Signed-off-by: Janusz Uzycki <j.uzycki@elproma.com.pl>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:56:47 -08:00
Markus Pargmann
d4ac0633ad tty: serial: omap: Remove probe error message
This error message is not necessary. The driver core code will print all
probe error messages. It also resolves some error codes to proper error
messages. For example -EPROBE_DEFER will only be printed as an info message.

This patch removes the error message as the core prints the same
information.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Acked-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:56:47 -08:00
Peter Hurley
91b32f5413 serial: core: Fix port count when uart_open() errors
A port count mismatch occurs if mutex_lock_interruptible()
exits uart_open() and the port has already been opened. This may
prematurely close a port on an open tty. Since uart_close() is _always_
called if uart_open() fails, the port count must be corrected if errors
occur.

Always increment the port count in uart_open(), regardless of errors;
always decrement the port count in uart_close(). Note that
tty_port_close_start() decrements the port count when uart_open()
was successful.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:55 -08:00
Peter Hurley
64dbee3105 serial: core: Remove extra locking in uart_write()
uart_start() only claims the port->lock to call __uart_start(),
which does the actual processing. Eliminate the extra acquire/release
in uart_write(); call __uart_start() directly with port->lock already
held.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:55 -08:00
Peter Hurley
2b702b9b68 serial: core: Colocate crucial structure linkage
The key function of uart_add_one_port() is to cross-reference the
UART driver's port structure with the serial core's state table;
keep the assignments together and document this crucial association.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:55 -08:00
Peter Hurley
1f0afd1607 serial: core: Remove redundant timeout assignments
tty_port_init() initializes close_delay and closing_wait to these
same values; remove.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:55 -08:00
Peter Hurley
74866e7593 serial: core: Unwrap >80 char line in uart_close()
The wrapped line looks wrong and out-of-place; leave it as
>80 char line.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:55 -08:00
Peter Hurley
7c8ab967e3 serial: Fix locking for uart driver set_termios() method
The low-level uart driver may modify termios settings to override
settings that are not compatible with the uart, such as CRTSCTS.
Thus, callers of the low-level uart driver's set_termios() method must
hold termios_rwsem write lock to prevent concurrent access to termios,
in case such override occurs.

The termios_rwsem lock requirement does not extend to console setup
(ie., uart_set_options), as console setup cannot race with tty
operations. Nor does this lock requirement extend to functions which
cannot be concurrent with tty ioctls (ie., uart_port_startup() and
uart_resume_port()).

Further, always claim the port mutex to protect hardware
re-reprogramming in the set_termios() uart driver method. Note this
is unnecessary for console initialization in uart_set_options()
which cannot be concurrent with other uart operations.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:54 -08:00
Peter Hurley
2e75891083 serial: core: Flush ldisc after dropping port mutex in uart_close()
The tty buffers (and any line discipline buffers) must be flushed after
the UART hardware has shutdown; otherwise, a racing open on the same
tty may receive data from the previous session, which is a security
hazard. However, holding the port mutex while flushing the line
discipline buffers creates a lock inversion if the set_termios()
handler takes the port mutex (as it does in the followup patch,
'serial: Fix locking for uart driver set_termios method'.

Flush the ldisc buffers after dropping the port mutex; the tty lock
is still held which prevents a concurrent open() from advancing while
flushing. Since no new rx data is possible after uart_shutdown() until
a new open reinitializes the port, the later flush has no impact on
what data is being discarded.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:54 -08:00
Peter Hurley
479e9b94fd serial: Refactor uart_flush_buffer() from uart_close()
In the context of the final tty & port close, flushing the tx
ring buffer after the hardware has already been shutdown and
the ring buffer freed is neither required nor desirable.

uart_flush_buffer() performs 3 operations:
1. Resets tx ring buffer indices, but the tx ring buffer has
   already been freed and the indices are reset if the port is
   re-opened.
2. Calls uart driver's flush_buffer() method
   5 in-tree uart drivers define flush_buffer() methods:
     amba-pl011, atmel-serial, imx, serial-tegra, timbuart
   These have been refactored into the shutdown() method, if
   required.
3. Kicks the ldisc for more writing, but this is undesirable.
   The file handle is being released; any waiting writer will
   will be kicked out by tty_release() with a warning. Further,
   the N_TTY ldisc may generate SIGIO for a file handle which
   is no longer valid.

Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 18:53:54 -08:00
Mike Skoog
1bc8cde46a 8250_pci: Added driver for Endrun Technologies PTP PCIe card.
Added recognition of EndRun Technologies PCIe PTP slave card
and setup two ttySx ports for communication with the card for
retrieval of PTP based time and to communicate with the card's
Linux OS.

Signed-off-by: Mike Skoog <mskoog@endruntechnologies.com>
Signed-off-by: Mike Korreng <mkorreng@endruntechnologies.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 16:36:01 -08:00
Sudhir Sreedharan
edf4edacb3 tty: serial: 8250_core: restore the LCR register in set_sleep
In ST16650V2 based serial uarts, while initalizing the PM state,
LCR registers are being initialized to 0 in serial8250_set_sleep().
If console port is already initialized and being used, this will
throws garbage in the console.

Signed-off-by: Sudhir Sreedharan <ssreedharan@mvista.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 16:23:34 -08:00
Jingchang Lu
513e438581 serial: of-serial: fix up PM ops on no_console_suspend and port type
This patch fixes commit 2dea53bf57,
"serial: of-serial: add PM suspend/resume support", which disables
the uart clock on suspend, but also causes a hardware hang on register
access if no_console_suspend command line option is used.

Also, not every of_serial device is an 8250 port, so the serial8250
suspend/resume functions should only be applied to a real 8250 port.

Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com>
Tested-by: Joseph Lo <josephl@nvidia.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 16:23:34 -08:00
Peter Hurley
91f189de46 serial: Fix sparse warnings in uart_throttle()/uart_unthrottle()
The struct uart_port.flags field is type upf_t, as are the matching
bit definitions. Change local mask variable to type upf_t.

Fixes sparse warnings:
drivers/tty/serial/serial_core.c:620:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:620:22:    left side has type unsigned int
drivers/tty/serial/serial_core.c:620:22:    right side has type restricted upf_t
drivers/tty/serial/serial_core.c:622:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:622:22:    left side has type unsigned int
drivers/tty/serial/serial_core.c:622:22:    right side has type restricted upf_t
drivers/tty/serial/serial_core.c:624:17: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:626:22: warning: invalid assignment: &=
drivers/tty/serial/serial_core.c:626:22:    left side has type unsigned int
drivers/tty/serial/serial_core.c:626:22:    right side has type restricted upf_t
drivers/tty/serial/serial_core.c:629:20: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:632:20: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:643:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:643:22:    left side has type unsigned int
drivers/tty/serial/serial_core.c:643:22:    right side has type restricted upf_t
drivers/tty/serial/serial_core.c:645:22: warning: invalid assignment: |=
drivers/tty/serial/serial_core.c:645:22:    left side has type unsigned int
drivers/tty/serial/serial_core.c:645:22:    right side has type restricted upf_t
drivers/tty/serial/serial_core.c:647:17: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:649:22: warning: invalid assignment: &=
drivers/tty/serial/serial_core.c:649:22:    left side has type unsigned int
drivers/tty/serial/serial_core.c:649:22:    right side has type restricted upf_t
drivers/tty/serial/serial_core.c:652:20: warning: restricted upf_t degrades to integer
drivers/tty/serial/serial_core.c:655:20: warning: restricted upf_t degrades to integer

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 16:15:43 -08:00
Peter Hurley
d4260b5169 serial: Fix upstat_t sparse warnings
Commit 299245a145,
serial: core: Privatize modem status enable flags, introduced
the upstat_t type and matching bit definitions. The purpose is to
produce sparse warnings if the wrong bit definitions are used
(by warning of implicit integer conversions).

Fix implicit conversion to integer return type from uart_cts_enabled()
and uart_dcd_enabled().

Fixes the following sparse warnings:
drivers/tty/serial/serial_core.c:63:30: warning: incorrect type in return expression (different base types)
drivers/tty/serial/serial_core.c:63:30:    expected int
drivers/tty/serial/serial_core.c:63:30:    got restricted upstat_t
include/linux/serial_core.h:364:30: warning: incorrect type in return expression (different base types)
include/linux/serial_core.h:364:30:    expected bool
include/linux/serial_core.h:364:30:    got restricted upstat_t
include/linux/serial_core.h:364:30: warning: incorrect type in return expression (different base types)
include/linux/serial_core.h:364:30:    expected bool
include/linux/serial_core.h:364:30:    got restricted upstat_t

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-11-05 16:15:43 -08:00
Linus Torvalds
52d589a01d Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma
Pull slave-dmaengine updates from Vinod Koul:
 "For dmaengine contributions we have:
   - designware cleanup by Andy
   - my series moving device_control users to dmanegine_xxx APIs for
     later removal of device_control API
   - minor fixes spread over drivers mainly mv_xor, pl330, mmp, imx-sdma
     etc"

* 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma: (60 commits)
  serial: atmel: add missing dmaengine header
  dmaengine: remove FSLDMA_EXTERNAL_START
  dmaengine: freescale: remove FSLDMA_EXTERNAL_START control method
  carma-fpga: move to fsl_dma_external_start()
  carma-fpga: use dmaengine_xxx() API
  dmaengine: freescale: add and export fsl_dma_external_start()
  dmaengine: add dmaengine_prep_dma_sg() helper
  video: mx3fb: use dmaengine_terminate_all() API
  serial: sh-sci: use dmaengine_terminate_all() API
  net: ks8842: use dmaengine_terminate_all() API
  mtd: sh_flctl: use dmaengine_terminate_all() API
  mtd: fsmc_nand: use dmaengine_terminate_all() API
  V4L2: mx3_camer: use dmaengine_pause() API
  dmaengine: coh901318: use dmaengine_terminate_all() API
  pata_arasan_cf: use dmaengine_terminate_all() API
  dmaengine: edma: check for echan->edesc => NULL in edma_dma_pause()
  dmaengine: dw: export probe()/remove() and Co to users
  dmaengine: dw: enable and disable controller when needed
  dmaengine: dw: always export dw_dma_{en,dis}able
  dmaengine: dw: introduce dw_dma_on() helper
  ...
2014-10-18 18:11:04 -07:00
Vinod Koul
6b997bab20 serial: atmel: add missing dmaengine header
The atmel serial driver uses dmaengine APIs but never included the dmaengine
header as it was getting inculded thru one of driver headers.

commit 3d588f83e4 - "dmaengine: dw: split
dma-dw.h to platform and private parts" broke this as it moved headers
around.  Fix this by doing the right thing to include the dmaengine header

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Fixes: 08f738be88 (serial: at91: add tx dma support)
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-10-16 14:08:05 +05:30
Vinod Koul
2856fcdc1f Merge branch 'topic/dma_control_cleanup_acks' into for-linus 2014-10-15 21:38:49 +05:30
Vinod Koul
2bcd90d56c serial: sh-sci: use dmaengine_terminate_all() API
The drivers should use dmaengine_terminate_all() API instead of
accessing the device_control which will be deprecated soon

Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-10-15 21:31:00 +05:30
Linus Torvalds
ea584595fc This is the bulk of GPIO changes for the v3.18 development
cycle:
 
 - Increase the default ARCH_NR_GPIO from 256 to 512. This
   was done to avoid having a custom <asm/gpio.h> header for
   the x86 architecture - GPIO is custom and complicated
   enough as it is already! We want to move to a radix to
   store the descriptors going forward, and finally get rid
   of this fixed array size altogether.
 
 - Endgame patching of the gpio_remove() semantics initiated
   by Abdoulaye Berthe. It is not accepted by the system that
   the removal of a GPIO chip fails during e.g. reboot or
   shutdown, and therefore the return value has now painfully
   been refactored away. For special cases like GPIO expanders
   on a hot-pluggable bus like USB, we may later add some
   gpiochip_try_remove() call, but for the cases we have now,
   return values are moot.
 
 - Some incremental refactoring of the gpiolib core and ACPI
   GPIO library for more descriptor usage.
 
 - Refactor the chained IRQ handler set-up method to handle
   also threaded, nested interrupts and set up the parent IRQ
   correctly. Switch STMPE and TC3589x drivers to use this
   registration method.
 
 - Add a .irq_not_threaded flag to the struct gpio_chip, so
   that also GPIO expanders that block but are still not
   using threaded IRQ handlers.
 
 - New drivers for the ARM64 X-Gene SoC GPIO controller.
 
 - The syscon GPIO driver has been improved to handle the
   "DSP GPIO" found on the TI Keystone 2 SoC:s.
 
 - ADNP driver switched to use gpiolib irqchip helpers.
 
 - Refactor the DWAPB driver to support being instantiated
   from and MFD cell (platform device).
 
 - Incremental feature improvement in the Zynq, MCP23S08,
   DWAPB, OMAP, Xilinx and Crystalcove drivers.
 
 - Various minor fixes.
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Merge tag 'gpio-v3.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio

Pull GPIO changes from Linus Walleij:
 "This is the bulk of GPIO changes for the v3.18 development cycle:

   - Increase the default ARCH_NR_GPIO from 256 to 512.  This was done
     to avoid having a custom <asm/gpio.h> header for the x86
     architecture - GPIO is custom and complicated enough as it is
     already! We want to move to a radix to store the descriptors going
     forward, and finally get rid of this fixed array size altogether.

   - Endgame patching of the gpio_remove() semantics initiated by
     Abdoulaye Berthe.  It is not accepted by the system that the
     removal of a GPIO chip fails during eg reboot or shutdown, and
     therefore the return value has now painfully been refactored away.
     For special cases like GPIO expanders on a hot-pluggable bus like
     USB, we may later add some gpiochip_try_remove() call, but for the
     cases we have now, return values are moot.

   - Some incremental refactoring of the gpiolib core and ACPI GPIO
     library for more descriptor usage.

   - Refactor the chained IRQ handler set-up method to handle also
     threaded, nested interrupts and set up the parent IRQ correctly.
     Switch STMPE and TC3589x drivers to use this registration method.

   - Add a .irq_not_threaded flag to the struct gpio_chip, so that also
     GPIO expanders that block but are still not using threaded IRQ
     handlers.

   - New drivers for the ARM64 X-Gene SoC GPIO controller.

   - The syscon GPIO driver has been improved to handle the "DSP GPIO"
     found on the TI Keystone 2 SoC:s.

   - ADNP driver switched to use gpiolib irqchip helpers.

   - Refactor the DWAPB driver to support being instantiated from and
     MFD cell (platform device).

   - Incremental feature improvement in the Zynq, MCP23S08, DWAPB, OMAP,
     Xilinx and Crystalcove drivers.

   - Various minor fixes"

* tag 'gpio-v3.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio: (52 commits)
  gpio: pch: Build context save/restore only for PM
  pinctrl: abx500: get rid of unused variable
  gpio: ks8695: fix 'else should follow close brace '}''
  gpio: stmpe: add verbose debug code
  gpio: stmpe: fix up interrupt enable logic
  gpio: staticize xway_stp_init()
  gpio: handle also nested irqchips in the chained handler set-up
  gpio: set parent irq on chained handlers
  gpiolib: irqchip: use irq_find_mapping while removing irqchip
  gpio: crystalcove: support virtual GPIO
  pinctrl: bcm281xx: make Kconfig dependency more strict
  gpio: kona: enable only on BCM_MOBILE or for compile testing
  gpio, bcm-kona, LLVMLinux: Remove use of __initconst
  gpio: Fix ngpio in gpio-xilinx driver
  gpio: dwapb: fix pointer to integer cast
  gpio: xgene: Remove unneeded #ifdef CONFIG_OF guard
  gpio: xgene: Remove unneeded forward declation for struct xgene_gpio
  gpio: xgene: Fix missing spin_lock_init()
  gpio: ks8695: fix switch case indentation
  gpiolib: add irq_not_threaded flag to gpio_chip
  ...
2014-10-09 14:58:15 -04:00
Linus Torvalds
683a52a101 TTY/Serial driver patches for 3.18-rc1
Here's the big tty/serial driver patchset for 3.18-rc1.
 
 Lots of little things in here, some good work from Peter Hurley on the
 tty core, and in lots of drivers.  There are also lots of other driver
 updates in here as well, full details in the changelog below.
 
 All have been in the linux-next tree for a while.
 
 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Merge tag 'tty-3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver updates from Greg KH:
 "Here's the big tty/serial driver patchset for 3.18-rc1.

  Lots of little things in here, some good work from Peter Hurley on the
  tty core, and in lots of drivers.  There are also lots of other driver
  updates in here as well, full details in the changelogs.

  All have been in the linux-next tree for a while"

* tag 'tty-3.18-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (99 commits)
  Revert "serial/core: Initialize the console pm state"
  tty: serial: 8250: use 32bit variable for rpm_tx_active
  tty: serial: msm: Add earlycon support
  serial/core: Initialize the console pm state
  serial: asc: Conditionally use readl_relaxed (COMPILE_TEST)
  serial: of-serial: add PM suspend/resume support
  m68k: AMIGA_BUILTIN_SERIAL should depend on TTY
  asm/uapi: Add definition of TIOC[SG]RS485
  tty/metag_da: Add console_poll module parameter
  serial: 8250_pci: remove rts_n override from Baytrail quirk
  serial: cadence: Add generic earlycon support
  serial: imx: change the wait even to interruptiable
  serial: imx: terminate the RX DMA when the UART is suspending
  serial: imx: fix throttle/unthrottle callbacks for hardware assisted flow control
  serial: 8250: Add Quark X1000 to 8250_pci.c
  tty: omap-serial: pull out calculation from baud_is_mode16
  tty: omap-serial: fix division by zero
  xen_hvc: no reason to write the type key on xenstore
  tty: serial: 8250_core: remove UART_IER_RDI in serial8250_stop_rx()
  tty: serial: 8250_core: use the ->line argument as a hint in serial8250_find_match_or_unused()
  ...
2014-10-08 06:52:11 -04:00
Linus Torvalds
bdf428feb2 Nothing major: support for compressing modules, and auto-tainting params.
Cheers,
 Rusty.
 PS.  My virtio-next tree is empty: DaveM took the patches I had.  There might
      be a virtio-rng starvation fix, but so far it's a bit voodoo so I will
      get to that in the next two days or it will wait.
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Merge tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

Pull module update from Rusty Russell:
 "Nothing major: support for compressing modules, and auto-tainting
  params.

  PS. My virtio-next tree is empty: DaveM took the patches I had.  There
      might be a virtio-rng starvation fix, but so far it's a bit voodoo
      so I will get to that in the next two days or it will wait"

* tag 'modules-next-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux:
  moduleparam: Resolve missing-field-initializer warning
  kbuild: handle module compression while running 'make modules_install'.
  modinst: wrap long lines in order to enhance cmd_modules_install
  modsign: lookup lines ending in .ko in .mod files
  modpost: simplify file name generation of *.mod.c files
  modpost: reduce visibility of symbols and constify r/o arrays
  param: check for tainting before calling set op.
  drm/i915: taint the kernel if unsafe module parameters are set
  module: add module_param_unsafe and module_param_named_unsafe
  module: make it possible to have unsafe, tainting module params
  module: rename KERNEL_PARAM_FL_NOARG to avoid confusion
2014-10-07 20:17:38 -04:00
Greg Kroah-Hartman
69784fa539 Revert "serial/core: Initialize the console pm state"
This reverts commit a86713b153.

Kevin Hilman writes:

	Multiple boot failures on ARM[1] were bisected down to this
	patch.

	How was this patch tested, and on which platforms?

	Also, the changelog states that this should be done only for
	UART_CAP_SLEEP, but the patch does it for every UART.

	Greg, I suggest this patch be dropped from tty-next until it has
	been better described and tested.

	[1] http://lists.linaro.org/pipermail/kernel-build-reports/2014-October/005550.html

Reported-by: Kevin Hilman <khilman@kernel.org>
Cc: Sudhir Sreedharan <ssreedharan@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-10-02 21:33:50 -07:00
Stephen Boyd
0efe729634 tty: serial: msm: Add earlycon support
Add support for DT based and command line based early console on platforms
with the msm serial hardware.

Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:49:48 -04:00
Sudhir Sreedharan
a86713b153 serial/core: Initialize the console pm state
For console devices having UART_CAP_SLEEP capability, the uart_pm_state has
to be initialized to UART_PM_STATE_ON. Otherwise the LCR regiser values
are reinitialized when uart_change_pm is called from uart_configure_port.

Signed-off-by: Sudhir Sreedharan <ssreedharan@mvista.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:49:48 -04:00
Daniel Thompson
daea65a7be serial: asc: Conditionally use readl_relaxed (COMPILE_TEST)
Commit 08177ece59 ("serial: asc: Adopt readl_/writel_relaxed()) is
regressing the m68k allmodconfig build. This is due to the unconditional
use of readl_relaxed() which, although documented, does not currently
exist for m68k.

This is trivially fixable for st-asc because we can just update the
asc_in() accessor to make this conditional.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Srinivas Kandagatla <srinivas.kandagatla@gmail.com>
Cc: Maxime Coquelin <maxime.coquelin@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:49:48 -04:00
Jingchang Lu
2dea53bf57 serial: of-serial: add PM suspend/resume support
This adds PM suspend/resume support for the of-serial driver
to provide power management support on devices attatched to it.

Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:49:13 -04:00
Heikki Krogerus
716e115cd7 serial: 8250_pci: remove rts_n override from Baytrail quirk
It should not be used together with Auto Flow Control, and
Auto Flow Control is always enabled on Baytrail.

Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:35:56 -04:00
Michal Simek
6fa62fc46e serial: cadence: Add generic earlycon support
Add earlycon support for the cadence serial port.
This is based on recent patches:
"tty/serial: pl011: add generic earlycon support"
(sha1: 0d3c673e78)
"tty/serial: add arm/arm64 semihosting earlycon"
(sha1: d50d7269eb)

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:32:37 -04:00
Huang Shijie
a4688bcd34 serial: imx: change the wait even to interruptiable
The wait_event() makes the application hang for ever in the following case:
 [1] the hardware flow control is enabled.
 [2] the other end (or the remote end) is terminated, and the TX is still
     waiting for the hardware flow control signal to become asserted.

This patch fixes it by changing the wait_event to wait_event_interruptible.

Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:26:38 -04:00
Huang Shijie
45564a6656 serial: imx: terminate the RX DMA when the UART is suspending
When the uart port is suspending, the RX data is useless.
So in this case, we can terminate the RX DMA right now.

Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:26:38 -04:00
Fugang Duan
bb2f861ad0 serial: imx: fix throttle/unthrottle callbacks for hardware assisted flow control
when the 'CTSC' bit is negated. 'CTS' has no function when 'CTSC' is asserted.
0: The CTS pin is high (inactive)
1: The CTS pin is low (active)

For throttle, it needs to clear 'CTS' and 'CTSC' bits.
For unthrottle, it needs to enable 'CTS' and 'CTSC' bits.

The patch just fix the issue.

Signed-off-by: Fugang Duan <B38611@freescale.com>
Signed-off-by: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:26:38 -04:00
Bryan O'Donoghue
1ede7dcca3 serial: 8250: Add Quark X1000 to 8250_pci.c
Quark X1000 contains two designware derived 8250 serial ports.
Each port has a unique PCI configuration space consisting of
BAR0:UART BAR1:DMA respectively.

Unlike the standard 8250 the register width is 32 bits for RHR,IER etc
The Quark UART has a fundamental clock @ 44.2368 MHz allowing for a
bitrate of up to about 2.76 megabits per second.

This patch enables standard 8250 mode

Signed-off-by: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:25:21 -04:00
Frans Klaver
13d6ceb4c4 tty: omap-serial: pull out calculation from baud_is_mode16
To determine the correct divisor, we need to know the difference between
the desired baud rate and the actual baud rate. The calculation for this
difference is implemented twice within omap_serial_baud_is_mode16().
Pull out the calculation for easier maintenance.

While at it, remove the CamelCasing from the variable names.

Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:24:06 -04:00
Frans Klaver
dc3187564e tty: omap-serial: fix division by zero
If the chosen baud rate is large enough (e.g. 3.5 megabaud), the
calculated n values in serial_omap_is_baud_mode16() may become 0. This
causes a division by zero when calculating the difference between
calculated and desired baud rates. To prevent this, cap the n13 and n16
values on 1.

Division by zero in kernel.
[<c00132e0>] (unwind_backtrace) from [<c00112ec>] (show_stack+0x10/0x14)
[<c00112ec>] (show_stack) from [<c01ed7bc>] (Ldiv0+0x8/0x10)
[<c01ed7bc>] (Ldiv0) from [<c023805c>] (serial_omap_baud_is_mode16+0x4c/0x68)
[<c023805c>] (serial_omap_baud_is_mode16) from [<c02396b4>] (serial_omap_set_termios+0x90/0x8d8)
[<c02396b4>] (serial_omap_set_termios) from [<c0230a0c>] (uart_change_speed+0xa4/0xa8)
[<c0230a0c>] (uart_change_speed) from [<c0231798>] (uart_set_termios+0xa0/0x1fc)
[<c0231798>] (uart_set_termios) from [<c022bb44>] (tty_set_termios+0x248/0x2c0)
[<c022bb44>] (tty_set_termios) from [<c022c17c>] (set_termios+0x248/0x29c)
[<c022c17c>] (set_termios) from [<c022c3e4>] (tty_mode_ioctl+0x1c8/0x4e8)
[<c022c3e4>] (tty_mode_ioctl) from [<c0227e70>] (tty_ioctl+0xa94/0xb18)
[<c0227e70>] (tty_ioctl) from [<c00cf45c>] (do_vfs_ioctl+0x4a0/0x560)
[<c00cf45c>] (do_vfs_ioctl) from [<c00cf568>] (SyS_ioctl+0x4c/0x74)
[<c00cf568>] (SyS_ioctl) from [<c000e480>] (ret_fast_syscall+0x0/0x30)

Signed-off-by: Frans Klaver <frans.klaver@xsens.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-28 21:23:45 -04:00
Sebastian Andrzej Siewior
9137568e73 tty: serial: 8250_core: remove UART_IER_RDI in serial8250_stop_rx()
serial8250_do_startup() adds UART_IER_RDI and UART_IER_RLSI to ier.
serial8250_stop_rx() should remove both.
This is what the serial-omap driver has been doing and is now moved to
the 8250-core since it does no look to be *that* omap specific.

Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-26 18:01:56 +02:00
Sebastian Andrzej Siewior
59b3e898dd tty: serial: 8250_core: use the ->line argument as a hint in serial8250_find_match_or_unused()
Tony noticed that the old omap-serial driver picked the uart "number"
based on the hint given from device tree or platform device's id.
The 8250 based omap driver doesn't do this because the core code does
not honour the ->line argument which is passed by the driver.

This patch aims to keep the same behaviour as with omap-serial. The
function will first try to use the line suggested ->line argument and
then fallback to the old strategy in case the port is taken.

That means the the third uart will always be ttyS2 even if the previous
two have not been enabled in DT.

Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-26 18:01:56 +02:00
Sebastian Andrzej Siewior
0aa525d118 tty: serial: 8250_core: read only RX if there is something in the FIFO
The serial8250_do_startup() function unconditionally clears the
interrupts and for that it reads from the RX-FIFO without checking if
there is a byte in the FIFO or not. This works fine on OMAP4+ HW like
AM335x or DRA7.
OMAP3630 ES1.1 (which means probably all OMAP3 and earlier) does not like
this:

|Unhandled fault: external abort on non-linefetch (0x1028) at 0xfb020000
|Internal error: : 1028 [#1] ARM
|Modules linked in:
|CPU: 0 PID: 1 Comm: swapper Not tainted 3.16.0-00022-g7edcb57-dirty #1213
|task: de0572c0 ti: de058000 task.ti: de058000
|PC is at mem32_serial_in+0xc/0x1c
|LR is at serial8250_do_startup+0x220/0x85c
|Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment kernel
|Control: 10c5387d  Table: 80004019  DAC: 00000015
|[<c03051d4>] (mem32_serial_in) from [<c0307fe8>] (serial8250_do_startup+0x220/0x85c)
|[<c0307fe8>] (serial8250_do_startup) from [<c0309e00>] (omap_8250_startup+0x5c/0xe0)
|[<c0309e00>] (omap_8250_startup) from [<c030863c>] (serial8250_startup+0x18/0x2c)
|[<c030863c>] (serial8250_startup) from [<c030394c>] (uart_startup+0x78/0x1d8)
|[<c030394c>] (uart_startup) from [<c0304678>] (uart_open+0xe8/0x114)
|[<c0304678>] (uart_open) from [<c02e9e10>] (tty_open+0x1a8/0x5a4)

Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-26 18:01:56 +02:00
Sebastian Andrzej Siewior
d74d5d1b72 tty: serial: 8250_core: add run time pm
While comparing the OMAP-serial and the 8250 part of this I noticed that
the latter does not use run time-pm. Here are the pieces. It is
basically a get before first register access and a last_busy + put after
last access. This has to be enabled from userland _and_ UART_CAP_RPM is
required for this.
The runtime PM can usually work transparently in the background however
there is one exception to this: After serial8250_tx_chars() completes
there still may be unsent bytes in the FIFO (depending on CPU speed vs
baud rate + flow control). Even if the TTY-buffer is empty we do not
want RPM to disable the device because it won't send the remaining
bytes. Instead we leave serial8250_tx_chars() with RPM enabled and wait
for the FIFO empty interrupt. Once we enter serial8250_tx_chars() with
an empty buffer we know that the FIFO is empty and since we are not going
to send anything, we can disable the device.
That xchg() is to ensure that serial8250_tx_chars() can be called
multiple times and only the first invocation will actually invoke the
runtime PM function. So that the last invocation of __stop_tx() will
disable runtime pm.

NOTE: do not enable RPM on the device unless you know what you do! If
the device goes idle, it won't be woken up by incomming RX data _unless_
there is a wakeup irq configured which is usually the RX pin configure
for wakeup via the reset module. The RX activity will then wake up the
device from idle. However the first character is garbage and lost. The
following bytes will be received once the device is up in time. On the
beagle board xm (omap3) it takes approx 13ms from the first wakeup byte
until the first byte that is received properly if the device was in
core-off.

v5…v8:
	- drop RPM from serial8250_set_mctrl() it will be used in
	  restore path which already has RPM active and holds
	  dev->power.lock
v4…v5:
	- add a wrapper around rpm function and introduce UART_CAP_RPM
	  to ensure RPM put is invoked after the TX FIFO is empty.
v3…v4:
	- added runtime to the console code
	- removed device_may_wakeup() from serial8250_set_sleep()

Cc: mika.westerberg@linux.intel.com
Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-26 18:01:56 +02:00
Sebastian Andrzej Siewior
234abab143 tty: serial: 8250_core: allow to set ->throttle / ->unthrottle callbacks
The OMAP UART provides support for HW assisted flow control. What is
missing is the support to throttle / unthrottle callbacks which are used
by the omap-serial driver at the moment.
This patch adds the callbacks. It should be safe to add them since they
are only invoked from the serial_core (uart_throttle()) if the feature
flags are set.

Reviewed-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-26 18:01:56 +02:00
Peter Hurley
938f7e13b5 serial: core: Use spin_lock_irq() in uart_set_termios()
uart_set_termios() is called with interrupts enabled; no need to
save and restore the interrupt state when taking the uart port lock.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-09-23 21:19:35 -07:00