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  1. 05 Jan, 2011 7 commits
    • Russell King's avatar
      ARM: PL011: add DMA burst threshold support for ST variants · 38d62436
      Russell King authored 
      ST Micro variants has some specific dma burst threshold compensation,
which allows them to make better use of a DMA controller.  Add support
to set this up.

Based on a patch from Linus Walleij.
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      38d62436
    • Russell King's avatar
      ARM: PL011: Add support for transmit DMA · 68b65f73
      Russell King authored 
      Add DMA engine support for transmit to the PL011 driver.  Based on a
patch from Linus Walliej, with the following changes:

- remove RX DMA support.  As PL011 doesn't give us receive timeout
  interrupts, we only get notified of received data when the RX DMA
  has completed.  This rather sucks for interactive use of the TTY.

- remove abuse of completions.  Completions are supposed to be for
  events, not to tell what condition buffers are in.  Replace it with
  a simple 'queued' bool.

- fix locking - it is only safe to access the circular buffer with the
  port lock held.

- only map the DMA buffer when required - if we're ever behind an IOMMU
  this helps keep IOMMU usage down, and also ensures that we're legal
  when we change the scatterlist entry length.

- fix XON/XOFF sending - we must send XON/XOFF characters out as soon
  as possible - waiting for up to 4095 characters in the DMA buffer
  to be sent first is not acceptable.

- fix XON/XOFF receive handling - we need to stop DMA when instructed
  to by the TTY layer, and restart it again when instructed to.  There
  is a subtle problem here: we must not completely empty the circular
  buffer with DMA, otherwise we will not be notified of XON.

- change the 'enable_dma' flag into a 'using DMA' flag, and track
  whether we can use TX DMA by whether the channel pointer is non-NULL.
  This gives us more control over whether we use DMA in the driver.

- we don't need to have the TX DMA buffer continually allocated for
  each port - instead, allocate it when the port starts up, and free
  it when it's shut down.  Update the 'using DMA' flag if we get
  the buffer, and adjust the TTY FIFO size appropriately.

- if we're going to use PIO to send characters, use the existing IRQ
  based functionality rather than reimplementing it.  This also ensures
  we call uart_write_wakeup() at the appropriate time, otherwise we'll
  stall.

- use DMA engine helper functions for type safety.

- fix init when built as a module - we can't have to initcall functions,
  so we must settle on one.  This means we can eliminate the deferred
  DMA initialization.

- there is no need to terminate transfers on a failed prep_slave_sg()
  call - nothing has been setup, so nothing needs to be terminated.
  This avoids a potential deadlock in the DMA engine code
  (tasklet->callback->failed prepare->terminate->tasklet_disable
   which then ends up waiting for the tasklet to finish running.)

- Dan says that the submission callback should not return an error:
  | dma_submit_error() is something I should have removed after commit
  | a0587bcf "ioat1: move descriptor allocation from submit to prep" all
  | errors should be notified by prep failing to return a descriptor
  | handle.  Negative dma_cookie_t values are only returned by the
  | dma_async_memcpy* calls which translate a prep failure into -ENOMEM.
  So remove the error handling at that point.  This also solves the
  potential deadlock mentioned in the previous comment.
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      68b65f73
    • Russell King's avatar
      ARM: PL011: Ensure IRQs are disabled in UART interrupt handler · 963cc981
      Russell King authored 
      As the DMA support introduces a separate interrupt-time callback, our
interrupt handler will not be the only handler which takes the port
lock, so we need to ensure that IRQs are disabled.  We must use the
_irqsave variant so we don't inadvertently enable interrupts.
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      963cc981
    • Russell King's avatar
      ARM: PL011: Separate hardware FIFO size from TTY FIFO size · ffca2b11
      Russell King authored 
      With DMA support, we need to tell the TTY subsystem that the DMA buffer
is the size of the FIFO, otherwise things like tty_wait_until_sent()
will time out too early.  Keep (and use) the hardware value separately
from the port->fifosize.

This was part of a larger patch from Linus Walleij, with a little
modification.
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      ffca2b11
    • Russell King's avatar
      ARM: PL011: Allow better handling of vendor data · c19f12b5
      Russell King authored 
      Rather than copying all vendor data into the port structure, copy
just that which is frequently used, and keep a pointer to the
remaining vendor data structure.  This makes it easier to add
vendor quirks in the future.
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      c19f12b5
    • Russell King's avatar
      ARM: PL011: Ensure error flags are clear at startup · 5063e2c5
      Russell King authored 
      The error flags weren't being cleared upon UART startup, which
can cause problems when we add DMA support.  It's good practice
to ensure that these flags are cleared anyway, so let's do so.

This was part of a larger patch from Linus Walleij.
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      5063e2c5
    • Russell King's avatar
      ARM: PL011: include revision number in boot-time port printk · e8a7ba86
      Russell King authored 
      Include the revision number of the PL011 primecell in the boot-time
port printk to allow proper identification of the peripheral.
Acked-by: default avatarLinus Walleij <linus.walleij@stericsson.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      e8a7ba86
  3. 09 Nov, 2010 5 commits
  5. 08 Nov, 2010 17 commits
  7. 06 Nov, 2010 7 commits
  9. 05 Nov, 2010 4 commits
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6 · 4b4a2700
      Linus Torvalds authored 
      * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6: (41 commits)
  inet_diag: Make sure we actually run the same bytecode we audited.
  netlink: Make nlmsg_find_attr take a const nlmsghdr*.
  fib: fib_result_assign() should not change fib refcounts
  netfilter: ip6_tables: fix information leak to userspace
  cls_cgroup: Fix crash on module unload
  memory corruption in X.25 facilities parsing
  net dst: fix percpu_counter list corruption and poison overwritten
  rds: Remove kfreed tcp conn from list
  rds: Lost locking in loop connection freeing
  de2104x: fix panic on load
  atl1 : fix panic on load
  netxen: remove unused firmware exports
  caif: Remove noisy printout when disconnecting caif socket
  caif: SPI-driver bugfix - incorrect padding.
  caif: Bugfix for socket priority, bindtodev and dbg channel.
  smsc911x: Set Ethernet EEPROM size to supported device's size
  ipv4: netfilter: ip_tables: fix information leak to userland
  ipv4: netfilter: arp_tables: fix information leak to userland
  cxgb4vf: remove call to stop TX queues at load time.
  cxgb4: remove call to stop TX queues at load time.
  ...
      4b4a2700
    • Linus Torvalds's avatar
      Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6 · f69fa764
      Linus Torvalds authored 
      * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6:
  firewire: ohci: fix race when reading count in AR descriptor
  firewire: ohci: avoid reallocation of AR buffers
  firewire: ohci: fix race in AR split packet handling
  firewire: ohci: fix buffer overflow in AR split packet handling
      f69fa764
    • Linus Torvalds's avatar
      Merge git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6 · 2e5c3672
      Linus Torvalds authored 
      * git://git.kernel.org/pub/scm/linux/kernel/git/sfrench/cifs-2.6:
  cifs: make cifs_set_oplock_level() take a cifsInodeInfo pointer
  cifs: dereferencing first then checking
  cifs: trivial comment fix: tlink_tree is now a rbtree
  [CIFS] Cleanup unused variable build warning
  cifs: convert tlink_tree to a rbtree
  cifs: store pointer to master tlink in superblock (try #2)
  cifs: trivial doc fix: note setlease implemented
  CIFS: Add cifs_set_oplock_level
  FS: cifs, remove unneeded NULL tests
      2e5c3672
    • Oleg Nesterov's avatar
      posix-cpu-timers: workaround to suppress the problems with mt exec · e0a70217
      Oleg Nesterov authored 
      posix-cpu-timers.c correctly assumes that the dying process does
posix_cpu_timers_exit_group() and removes all !CPUCLOCK_PERTHREAD
timers from signal->cpu_timers list.

But, it also assumes that timer->it.cpu.task is always the group
leader, and thus the dead ->task means the dead thread group.

This is obviously not true after de_thread() changes the leader.
After that almost every posix_cpu_timer_ method has problems.

It is not simple to fix this bug correctly. First of all, I think
that timer->it.cpu should use struct pid instead of task_struct.
Also, the locking should be reworked completely. In particular,
tasklist_lock should not be used at all. This all needs a lot of
nontrivial and hard-to-test changes.

Change __exit_signal() to do posix_cpu_timers_exit_group() when
the old leader dies during exec. This is not the fix, just the
temporary hack to hide the problem for 2.6.37 and stable. IOW,
this is obviously wrong but this is what we currently have anyway:
cpu timers do not work after mt exec.

In theory this change adds another race. The exiting leader can
detach the timers which were attached to the new leader. However,
the window between de_thread() and release_task() is small, we
can pretend that sys_timer_create() was called before de_thread().
Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e0a70217
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