linux-stable.git/drivers/tty/serial/pch_uart.c, branch linux-3.4.y

serial: pch_uart: fix tty-kref leak in rx-error path

2014-06-11T19:04:21+00:00

commit fc0919c68cb2f75bb1af759315f9d7e2a9443c28 upstream.

Fix tty-kref leak introduced by commit 384e301e ("pch_uart: fix a
deadlock when pch_uart as console") which never put its tty reference.

Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Ben Hutchings 
Cc: Rui Xiang 
Signed-off-by: Greg Kroah-Hartman

serial: pch_uart: fix tty-kref leak in dma-rx path

2014-06-11T19:04:21+00:00

commit 19b85cfb190eb9980eaf416bff96aef4159a430e upstream.

Fix tty_kref leak when tty_buffer_request room fails in dma-rx path.

Note that the tty ref isn't really needed anymore, but as the leak has
always been there, fixing it before removing should makes it easier to
backport the fix.

Signed-off-by: Johan Hovold 
Signed-off-by: Greg Kroah-Hartman 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings 
Cc: Rui Xiang 
Signed-off-by: Greg Kroah-Hartman

pch_uart: fix a deadlock when pch_uart as console

2013-07-03T17:59:05+00:00

commit 384e301e3519599b000c1a2ecd938b533fc15d85 upstream.

When we use pch_uart as system console like 'console=ttyPCH0,115200',
then 'send break' to it. We'll encounter the deadlock on a cpu/core,
with interrupts disabled on the core. When we happen to have all irqs
affinity to cpu0 then the deadlock on cpu0 actually deadlock whole
system.

In pch_uart_interrupt, we have spin_lock_irqsave(&priv->lock, flags)
then call pch_uart_err_ir when break is received. Then the call to
dev_err would actually call to pch_console_write then we'll run into
another spin_lock(&priv->lock), with interrupts disabled.

So in the call sequence lead by pch_uart_interrupt, we should be
carefully to call functions that will 'print message to console' only
in case the uart port is not being used as serial console.

Signed-off-by: Liang Li 
Cc: Yijing Wang 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Add eg20t_port lock field, avoid recursive spinlocks

2012-10-02T17:30:37+00:00

commit 2588aba002d14e938c2f56d299ecf3e7ce1302a5 upstream.

pch_uart_interrupt() takes priv->port.lock which leads to two recursive
spinlock calls if low_latency==1 or CONFIG_PREEMPT_RT_FULL=y (one
otherwise):

pch_uart_interrupt
  spin_lock_irqsave(priv->port.lock, flags)
  case PCH_UART_IID_RDR_TO (data ready)
  handle_rx_to
    push_rx
      tty_port_tty_get
        spin_lock_irqsave(&port->lock, flags) <--- already hold this lock
        ...
      tty_flip_buffer_push
        ...
        flush_to_ldisc
          spin_lock_irqsave(&tty->buf.lock)
            spin_lock_irqsave(&tty->buf.lock)
            disc->ops->receive_buf(tty, char_buf)
              n_tty_receive_buf
                tty->ops->flush_chars()
                uart_flush_chars
                  uart_start
                    spin_lock_irqsave(&port->lock) <--- already hold this lock

Avoid this by using a dedicated lock to protect the eg20t_port structure
and IO access to its membase. This is more consistent with the 8250
driver.  Ensure priv->lock is always take prior to priv->port.lock when
taken at the same time.

V2: Remove inadvertent whitespace change.
V3: Account for oops_in_progress for the private lock in
    pch_console_write().

Note: Like the 8250 driver, if a printk is introduced anywhere inside
      the pch_console_write() critical section, the kernel will hang
      on a recursive spinlock on the private lock. The oops case is
      handled by using a trylock in the oops_in_progress case.

Signed-off-by: Darren Hart 
CC: Tomoya MORINAGA 
CC: Feng Tang 
CC: Alexander Stein 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Fix parity setting issue

2012-10-02T17:30:36+00:00

commit 38bd2a1ac736901d1cf4971c78ef952ba92ef78b upstream.

Parity Setting value is reverse.
E.G. In case of setting ODD parity, EVEN value is set.
This patch inverts "if" condition.

Signed-off-by: Tomoya MORINAGA 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Fix rx error interrupt setting issue

2012-10-02T17:30:36+00:00

commit 9539dfb7ac1c84522fe1f79bb7dac2990f3de44a upstream.

Rx Error interrupt(E.G. parity error) is not enabled.
So, when parity error occurs, error interrupt is not occurred.
As a result, the received data is not dropped.

This patch adds enable/disable rx error interrupt code.

Signed-off-by: Tomoya MORINAGA 
Acked-by: Alan Cox 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Fix missing break for 16 byte fifo

2012-10-02T17:30:36+00:00

commit 9bc03743fff0770dc5a5324ba92e67cc377f16ca upstream.

Otherwise we fall back to the wrong value.

Reported-by: 
Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=44091
Signed-off-by: Alan Cox 
Signed-off-by: Tomoya MORINAGA 
Signed-off-by: Greg Kroah-Hartman

pch_uart: Fix dma channel unallocated issue

2012-04-18T22:19:50+00:00

This driver anticipates pch_uart_verify_port() is not called
during installation.
However, actually pch_uart_verify_port() is called during
installation.
As a result, memory access violation occurs like below.

0. initial value: use_dma=0
1. starup()
    - dma channel is not allocated because use_dma=0
2. pch_uart_verify_port()
    - Set use_dma=1
3. UART processing acts DMA mode because use_dma=1
     - memory access violation occurs!

This patch fixes the issue.

Solution:
Whenever pch_uart_verify_port() is called and then
dma channel is not allocated, the channel should be allocated.

Signed-off-by: Tomoya MORINAGA 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2012-04-12T22:36:33+00:00

Pull tty and serial fixes from Greg KH:
 "Here are some tty and serial fixes for 3.4-rc2.

  Most important here is the pl011 fix, which has been reported by about
  100 different people, which means more people use it than I expected
  :)

  There are also some 8250 driver reverts due to some problems reported
  by them.  And other minor fixes as well.

  Signed-off-by: Greg Kroah-Hartman "

* tag 'tty-3.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  pch_uart: Add Kontron COMe-mTT10 uart clock quirk
  pch_uart: Fix MSI setting issue
  serial/8250_pci: add a "force background timer" flag and use it for the "kt" serial port
  Revert "serial/8250_pci: setup-quirk workaround for the kt serial controller"
  Revert "serial/8250_pci: init-quirk msi support for kt serial controller"
  tty/serial/omap: console can only be built-in
  serial: samsung: fix omission initialize ulcon in reset port fn()
  printk(): add KERN_CONT where needed in hpet and vt code
  tty/serial: atmel_serial: fix RS485 half-duplex problem
  tty: serial: altera_uart: Check for NULL platform_data in probe.
  isdn/gigaset: use gig_dbg() for debugging output
  omap-serial: Fix the error handling in the omap_serial probe
  serial: PL011: move interrupt clearing

pch_uart: Add Kontron COMe-mTT10 uart clock quirk

2012-04-09T17:58:41+00:00

Add UART clock quirk for the Kontron COMe-mTT10 module.

The board has previously been called nanoETXexpress-TT, therefore this
is also checked.

As suggested by Darren Hart the comparison in this patch version is
placed after the FRI2 checks to ensure it will also work with possible
upcoming changes to the FRI2 firmware.

This patch follows the patchset submitted by Darren Hart at
commit a46f5533ecfc7bbdd646d84fdab8656031a715c6.

Signed-off-by: Michael Brunner 
Acked-by: Darren Hart 
Signed-off-by: Greg Kroah-Hartman