linux-stable.git/drivers/tty/serial, branch v3.2.16

serial: PL011: move interrupt clearing

2012-04-22T22:31:11+00:00

commit c3d8b76f61586714cdc5f219ba45592a54caaa55 upstream.

Commit 360f748b204275229f8398cb2f9f53955db1503b
"serial: PL011: clear pending interrupts"
attempts to clear interrupts by writing to a
yet-unassigned memory address. This fixes the issue.

The breaking patch is marked for stable so should be
carried along with the other patch.

Cc: Shreshtha Kumar Sahu 
Cc: Russell King 
Cc: Nicolas Pitre 
Reported-by: Viresh Kumar 
Signed-off-by: Linus Walleij 
Tested-by: Grant Likely 
Signed-off-by: Greg Kroah-Hartman

serial: PL011: clear pending interrupts

2012-04-22T22:31:11+00:00

commit 9b96fbacda34079dea0638ee1e92c56286f6114a upstream.

Chanho Min reported that when the boot loader transfers
control to the kernel, there may be pending interrupts
causing the UART to lock up in an eternal loop trying to
pick tokens from the FIFO (since the RX interrupt flag
indicates there are tokens) while in practice there are
no tokens - in fact there is only a pending IRQ flag.

This patch address the issue with a combination of two
patches suggested by Russell King that clears and mask
all interrupts at probe() and clears any pending error
and RX interrupts at port startup time.

We suspect the spurious interrupts are a side-effect of
switching the UART from FIFO to non-FIFO mode.

Cc: Shreshtha Kumar Sahu 
Reported-by: Chanho Min 
Suggested-by: Russell King 
Signed-off-by: Linus Walleij 
Reviewed-by: Jong-Sung Kim 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Fix MSI setting issue

2012-04-22T22:31:01+00:00

commit 867c902e07d5677e2a5b54c0435e589513abde48 upstream.

The following patch (MSI setting) is not enough.

commit e463595fd9c752fa4bf06b47df93ef9ade3c7cf0
Author: Alexander Stein 
Date:   Mon Jul 4 08:58:31 2011 +0200

    pch_uart: Add MSI support

    Signed-off-by: Alexander Stein 
    Signed-off-by: Greg Kroah-Hartman 

To enable MSI mode, PCI bus-mastering must be enabled.
This patch enables the setting.

cc: Alexander Stein 
Signed-off-by: Tomoya MORINAGA 
Signed-off-by: Greg Kroah-Hartman

tty: serial: altera_uart: Check for NULL platform_data in probe.

2012-04-22T22:31:00+00:00

commit acede70d6561f2d042d9dbb153d9a3469479c0ed upstream.

Follow altera_jtag_uart.  This fixes a crash if there is a mistake in the DTS.

Signed-off-by: Yuriy Kozlov 
Signed-off-by: Tobias Klauser 
Signed-off-by: Greg Kroah-Hartman

serial: sh-sci: fix a race of DMA submit_tx on transfer

2012-04-02T16:53:10+00:00

commit 49d4bcaddca977fffdea8b0b71f6e5da96dac78e upstream.

When DMA is enabled, sh-sci transfer begins with
 uart_start()
  sci_start_tx()
    if (cookie_tx < 0) schedule_work()
Then, starts DMA when wq scheduled, -- (A)
 process_one_work()
  work_fn_rx()
   cookie_tx = desc->submit_tx()
And finishes when DMA transfer ends, -- (B)
 sci_dma_tx_complete()
  async_tx_ack()
  cookie_tx = -EINVAL
  (possible another schedule_work())

This A to B sequence is not reentrant, since controlling variables
(for example, cookie_tx above) are not queues nor lists. So, they
must be invoked as A B A B..., otherwise results in kernel crash.

To ensure the sequence, sci_start_tx() seems to test if cookie_tx < 0
(represents "not used") to call schedule_work().
But cookie_tx will not be set (to a cookie, also means "used") until
in the middle of work queue scheduled function work_fn_tx().

This gap between the test and set allows the breakage of the sequence
under the very frequently call of uart_start().
Another gap between async_tx_ack() and another schedule_work() results
in the same issue, too.

This patch introduces a new condition "cookie_tx == 0" just to mark
it is "busy" and assign it within spin-locked region to fill the gaps.

Signed-off-by: Takashi Yoshii 
Reviewed-by: Guennadi Liakhovetski 
Signed-off-by: Paul Mundt 
Signed-off-by: Greg Kroah-Hartman

jsm: Fixed EEH recovery error

2012-02-03T17:22:07+00:00

commit 26aa38cafae0dbef3b2fe75ea487c83313c36d45 upstream.

There was an error on the jsm driver that would cause it to be unable to
recover after a second error is detected.

At the first error, the device recovers properly:

[72521.485691] EEH: Detected PCI bus error on device 0003:02:00.0
[72521.485695] EEH: This PCI device has failed 1 times in the last hour:
...
[72532.035693] ttyn3 at MMIO 0x0 (irq = 49) is a jsm
[72532.105689] jsm: Port 3 added

However, at the second error, it cascades until EEH disables the device:

[72631.229549] Call Trace:
...
[72641.725687] jsm: Port 3 added
[72641.725695] EEH: Detected PCI bus error on device 0003:02:00.0
[72641.725698] EEH: This PCI device has failed 3 times in the last hour:

It was caused because the PCI state was not being saved after the first
restore. Therefore, at the second recovery the PCI state would not be
restored.

Signed-off-by: Lucas Kannebley Tavares 
Signed-off-by: Breno Leitao 
Acked-by: Thadeu Lima de Souza Cascardo 
Signed-off-by: Greg Kroah-Hartman

serial: amba-pl011: lock console writes against interrupts

2012-02-03T17:22:07+00:00

commit ef605fdb33883d687cff5ba75095a91b313b4966 upstream.

Protect against pl011_console_write() and the interrupt for
the console UART running concurrently on different CPUs.

Otherwise the console_write could spin for a long time
waiting for the UART to become not busy, while the other
CPU continuously services UART interrupts and keeps the
UART busy.

The checks for sysrq and oops_in_progress are taken
from 8250.c.

Signed-off-by: Rabin Vincent 
Reviewed-by: Srinidhi Kasagar 
Reviewed-by: Bibek Basu 
Reviewed-by: Shreshtha Kumar Sahu 
Signed-off-by: Linus Walleij 
Signed-off-by: Greg Kroah-Hartman

atmel_serial: fix spinlock lockup in RS485 code

2012-01-12T19:29:35+00:00

commit dbf1115d3f8c7052788aa4e6e46abd27f3b3eeba upstream.

Patch to fix a spinlock lockup in the driver that sometimes happens when the
tasklet starts.

Signed-off-by: Claudio Scordino 
Signed-off-by: Dave Bender 
Tested-by: Dave Bender 
Acked-by: Nicolas Ferre 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2011-11-22T04:36:46+00:00

* 'tty-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  TTY: ldisc, wait for ldisc infinitely in hangup
  TTY: ldisc, move wait idle to caller
  TTY: ldisc, allow waiting for ldisc arbitrarily long
  Revert "tty/serial: Prevent drop of DCD on suspend for Tegra UARTs"
  RS485: fix inconsistencies in the meaning of some variables
  pch_uart: Fix DMA resource leak issue
  serial,mfd: Fix CMSPAR setup
  tty/serial: Prevent drop of DCD on suspend for Tegra UARTs
  pch_uart: Change company name OKI SEMICONDUCTOR to LAPIS Semiconductor
  pch_uart: Support new device LAPIS Semiconductor ML7831 IOH
  pch_uart: Fix hw-flow control issue
  tty: hvc_dcc: Fix duplicate character inputs
  jsm: Change maintainership

Revert "tty/serial: Prevent drop of DCD on suspend for Tegra UARTs"

2011-11-16T00:01:09+00:00

This reverts commit 9636b755da7b498094bdf15b4ce9f6fd16995e4e.

It wasn't supposed to be applied, thanks to Doug for letting me know.

Cc: Doug Anderson 
Signed-off-by: Greg Kroah-Hartman