Eric Lee / smarc-fsl-linux-kernel

21 Jul, 2008

1 commit

03 Feb, 2008

1 commit

17 Feb, 2007

1 commit

09 Dec, 2006

1 commit

  • 606d099cd   [PATCH] tty: switch to ktermios ... Browse Code »

    This is the grungy swap all the occurrences in the right places patch that
    goes with the updates. At this point we have the same functionality as
    before (except that sgttyb() returns speeds not zero) and are ready to
    begin turning new stuff on providing nobody reports lots of bugs

    If you are a tty driver author converting an out of tree driver the only
    impact should be termios->ktermios name changes for the speed/property
    setting functions from your upper layers.

    If you are implementing your own TCGETS function before then your driver
    was broken already and its about to get a whole lot more painful for you so
    please fix it 8)

    Also fill in c_ispeed/ospeed on init for most devices, although the current
    code will do this for you anyway but I'd like eventually to lose that extra
    paranoia

    [akpm@osdl.org: bluetooth fix]
    [mp3@de.ibm.com: sclp fix]
    [mp3@de.ibm.com: warning fix for tty3270]
    [hugh@veritas.com: fix tty_ioctl powerpc build]
    [jdike@addtoit.com: uml: fix ->set_termios declaration]
    Signed-off-by: Alan Cox
    Signed-off-by: Martin Peschke
    Acked-by: Peter Oberparleiter
    Cc: Cornelia Huck
    Signed-off-by: Hugh Dickins
    Signed-off-by: Jeff Dike
    Cc: Paolo 'Blaisorblade' Giarrusso
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

08 Dec, 2006

7 commits

07 Oct, 2006

1 commit

01 Oct, 2006

1 commit

01 Jul, 2006

1 commit

31 Mar, 2006

1 commit

05 Feb, 2006

1 commit

11 Jan, 2006

1 commit

  • 33f0f88f1   [PATCH] TTY layer buffering revamp ... Browse Code »

    The API and code have been through various bits of initial review by
    serial driver people but they definitely need to live somewhere for a
    while so the unconverted drivers can get knocked into shape, existing
    drivers that have been updated can be better tuned and bugs whacked out.

    This replaces the tty flip buffers with kmalloc objects in rings. In the
    normal situation for an IRQ driven serial port at typical speeds the
    behaviour is pretty much the same, two buffers end up allocated and the
    kernel cycles between them as before.

    When there are delays or at high speed we now behave far better as the
    buffer pool can grow a bit rather than lose characters. This also means
    that we can operate at higher speeds reliably.

    For drivers that receive characters in blocks (DMA based, USB and
    especially virtualisation) the layer allows a lot of driver specific
    code that works around the tty layer with private secondary queues to be
    removed. The IBM folks need this sort of layer, the smart serial port
    people do, the virtualisers do (because a virtualised tty typically
    operates at infinite speed rather than emulating 9600 baud).

    Finally many drivers had invalid and unsafe attempts to avoid buffer
    overflows by directly invoking tty methods extracted out of the innards
    of work queue structs. These are no longer needed and all go away. That
    fixes various random hangs with serial ports on overflow.

    The other change in here is to optimise the receive_room path that is
    used by some callers. It turns out that only one ldisc uses receive room
    except asa constant and it updates it far far less than the value is
    read. We thus make it a variable not a function call.

    I expect the code to contain bugs due to the size alone but I'll be
    watching and squashing them and feeding out new patches as it goes.

    Because the buffers now dynamically expand you should only run out of
    buffering when the kernel runs out of memory for real. That means a lot of
    the horrible hacks high performance drivers used to do just aren't needed any
    more.

    Description:

    tty_insert_flip_char is an old API and continues to work as before, as does
    tty_flip_buffer_push() [this is why many drivers dont need modification]. It
    does now also return the number of chars inserted

    There are also

    tty_buffer_request_room(tty, len)

    which asks for a buffer block of the length requested and returns the space
    found. This improves efficiency with hardware that knows how much to
    transfer.

    and tty_insert_flip_string_flags(tty, str, flags, len)

    to insert a string of characters and flags

    For a smart interface the usual code is

    len = tty_request_buffer_room(tty, amount_hardware_says);
    tty_insert_flip_string(tty, buffer_from_card, len);

    More description!

    At the moment tty buffers are attached directly to the tty. This is causing a
    lot of the problems related to tty layer locking, also problems at high speed
    and also with bursty data (such as occurs in virtualised environments)

    I'm working on ripping out the flip buffers and replacing them with a pool of
    dynamically allocated buffers. This allows both for old style "byte I/O"
    devices and also helps virtualisation and smart devices where large blocks of
    data suddenely materialise and need storing.

    So far so good. Lots of drivers reference tty->flip.*. Several of them also
    call directly and unsafely into function pointers it provides. This will all
    break. Most drivers can use tty_insert_flip_char which can be kept as an API
    but others need more.

    At the moment I've added the following interfaces, if people think more will
    be needed now is a good time to say

    int tty_buffer_request_room(tty, size)

    Try and ensure at least size bytes are available, returns actual room (may be
    zero). At the moment it just uses the flipbuf space but that will change.
    Repeated calls without characters being added are not cumulative. (ie if you
    call it with 1, 1, 1, and then 4 you'll have four characters of space. The
    other functions will also try and grow buffers in future but this will be a
    more efficient way when you know block sizes.

    int tty_insert_flip_char(tty, ch, flag)

    As before insert a character if there is room. Now returns 1 for success, 0
    for failure.

    int tty_insert_flip_string(tty, str, len)

    Insert a block of non error characters. Returns the number inserted.

    int tty_prepare_flip_string(tty, strptr, len)

    Adjust the buffer to allow len characters to be added. Returns a buffer
    pointer in strptr and the length available. This allows for hardware that
    needs to use functions like insl or mencpy_fromio.

    Signed-off-by: Alan Cox
    Cc: Paul Fulghum
    Signed-off-by: Hirokazu Takata
    Signed-off-by: Serge Hallyn
    Signed-off-by: Jeff Dike
    Signed-off-by: John Hawkes
    Signed-off-by: Martin Schwidefsky
    Signed-off-by: Adrian Bunk
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Alan Cox
     

18 Nov, 2005

2 commits

  • a137ce853   [PARISC] Define port->timeout to fix a long msleep in mux.c ... Browse Code »

    This commit is in response to a bug reported by Vesa on the irc channel
    a couple of weeks ago.

    The bug was that the console would apparently hang (not return) while
    using the mux console.

    The root cause of this bug is that bash (with readline support) makes a
    call to the tcsetattr() glibc function with the argument TCSADRAIN. This
    causes the serial core in the kernel use the uart_wait_until_sent() to be
    called. This function verifies the mux transmit queue is empty or calls the
    msleep_interruptable() with a calculated timeout value that is dependant
    upon the port->timeout variable.

    The real problem here is that the port->timeout was not defined so it
    was defaulted to 0 and the timeout calculation performs the following
    calculation:

    char_time = (port->timeout - HZ/50) / port->fifosize;

    where char_time is an unsigned long. Since the serial Mux does not use
    interrupts, the msleep_interruptable() function waits until the timeout
    has been reached ... and when the port->timeout < HZ/50 this timeout will
    be a long time. (I have validated that the console will eventually
    return ... but it takes quite a while for this to happen).

    This patch simply sets the port->timeout on the Mux to HZ/50 to avoid
    this long timeout period.

    Signed-off-by: Ryan Bradetich
    Signed-off-by: Kyle McMartin

    Ryan Bradetich
     
  • 92495c0eb   [PARISC] Compile fixups for serial/mux.c ... Browse Code »

    This patch does the following:
    * Fixes compiler warnings.
    * Replaces a __raw_readl call with the existing macro.

    Signed-off-by: Ryan Bradetich
    Signed-off-by: Kyle McMartin

    Ryan Bradetich
     

22 Oct, 2005

3 commits

31 Aug, 2005

1 commit

  • b129a8ccd   [SERIAL] Clean up and fix tty transmission start/stoping ... Browse Code »

    The start_tx and stop_tx methods were passed a flag to indicate
    whether the start/stop was from the tty start/stop callbacks, and
    some drivers used this flag to decide whether to ask the UART to
    immediately stop transmission (where the UART supports such a
    feature.)

    There are other cases when we wish this to occur - when CTS is
    lowered, or if we change from soft to hard flow control and CTS
    is inactive. In these cases, this flag was false, and we would
    allow the transmitter to drain before stopping.

    There is really only one case where we want to let the transmitter
    drain before disabling, and that's when we run out of characters
    to send.

    Hence, re-jig the start_tx and stop_tx methods to eliminate this
    flag, and introduce new functions for the special "disable and
    allow transmitter to drain" case.

    Signed-off-by: Russell King

    Russell King
     

17 Apr, 2005

1 commit

  • 1da177e4c   Linux-2.6.12-rc2 ... Browse Code »

    Initial git repository build. I'm not bothering with the full history,
    even though we have it. We can create a separate "historical" git
    archive of that later if we want to, and in the meantime it's about
    3.2GB when imported into git - space that would just make the early
    git days unnecessarily complicated, when we don't have a lot of good
    infrastructure for it.

    Let it rip!

    Linus Torvalds