linux-toradex.git/drivers/tty, branch v3.3.3

serial: PL011: move interrupt clearing

2012-04-22T22:39:16+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

2012-04-22T22:39:16+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

2012-04-22T22:38:59+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.

2012-04-22T22:38:57+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/8250_pci: add a "force background timer" flag and use it for the "kt" serial port

2012-04-22T22:38:57+00:00

commit bc02d15a3452fdf9276e8fb89c5e504a88df888a upstream.

Workaround dropped notifications in the iir register.  Register reads
coincident with new interrupt notifications sometimes result in this
device clearing the interrupt event without reporting it in the read
data.

The serial core already has a heuristic for determining when a device
has an untrustworthy iir register.  In this case when we apriori know
that the iir is faulty use a flag (UPF_BUG_THRE) to bypass the test and
force usage of the background timer.

Acked-by: Alan Cox 
Reported-by: Nhan H Mai 
Reported-by: Sudhakar Mamillapalli 
Tested-by: Nhan H Mai 
Tested-by: Sudhakar Mamillapalli 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman

Revert "serial/8250_pci: setup-quirk workaround for the kt serial controller"

2012-04-22T22:38:57+00:00

commit 49b532f96fda23663f8be35593d1c1372c0f91e0 upstream.

This reverts commit 448ac154c957c4580531fa0c8f2045816fe2f0e7.

The semantic of UPF_IIR_ONCE is only guaranteed to workaround the race
condition in the kt serial's iir register if the only source of
interrupts is THRE (fifo-empty) events.  An modem status event at the
wrong time can again cause an iir read to drop the 'empty' status
leading to a hang.  So, revert this in preparation for using the
existing "I don't trust my iir register" workaround in the 8250 core
(UART_BUG_THRE).

Acked-by: Alan Cox 
Cc: Sudhakar Mamillapalli 
Reported-by: Nhan H Mai 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman

serial: samsung: fix omission initialize ulcon in reset port fn()

2012-04-22T22:38:57+00:00

commit 7b246a1d0dfe75346a22bf6589b858a0389e6df1 upstream.

Fix omission initialize ulcon in s3c24xx_serial_resetport(),
reset port function in drivers/tty/serial/samsung.c. It has
been happened from commit 0dfb3b41("serial: samsung: merge
all SoC specific port reset functions")

Signed-off-by: Kukjin Kim 
Signed-off-by: Greg Kroah-Hartman

Revert "serial/8250_pci: init-quirk msi support for kt serial controller"

2012-04-22T22:38:57+00:00

commit 3579812373aba92b2f3b632bdf99329bc3c05d62 upstream.

This reverts commit e86ff4a63c9fdd875ba8492577cd1ad2252f525c.

This tried to enforce the semantics of one interrupt per iir read of the
THRE (transmit-hold empty) status, but events from other sources
(particularly modem status) defeat this guarantee.

This change also broke 8250_pci suspend/resume support as
pciserial_resume_ports() re-runs .init() quirks, but does not run
.exit() quirks in pciserial_suspend_ports() leading to reports like:

  sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:16.3/msi_irqs'

...and a subsequent crash.  The mismatch of init/exit at suspend/resume
seems like a bug in its own right.

Acked-by: Alan Cox 
Cc: Sudhakar Mamillapalli 
Reported-by: Nhan H Mai 
Signed-off-by: Dan Williams 
Signed-off-by: Greg Kroah-Hartman

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

2012-04-02T17:32:24+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

TTY: Wrong unicode value copied in con_set_unimap()

2012-04-02T17:31:35+00:00

commit 4a4c61b7ce26bfc9d49ea4bd121d52114bad9f99 upstream.

Bugzilla 40012: PIO_UNIMAP bug: error updating Unicode-to-font map
https://bugzilla.kernel.org/show_bug.cgi?id=40012

The unicode font map for the virtual console is a 32x32x64 table which
allocates rows dynamically as entries are added.  The unicode value
increases sequentially and should count all entries even in empty
rows.  The defect is when copying the unicode font map in con_set_unimap(),
the unicode value is not incremented properly.  The wrong unicode value
is entered in the new font map.

Signed-off-by: Liz Clark 
Signed-off-by: Greg Kroah-Hartman