25 Jul, 2008

1 commit

  • Changes to the generic console support code that happened a while ago
    introduced a scenario where the initial console is used in parallel with
    the final console during a brief period when switching between the two is
    in progress. During that time a message about the switch-over is printed.

    With some combinations of chips, firmware and drivers, such as the DEC
    DZ11 clone used with the DECstation, a hang may happen because the
    firmware used for the initial console may not expect the state of the chip
    after it has been initialised by the driver.

    This is a workaround for the DZ11 which reuses the power-management
    callback to keep the transmitter of the line associated with the console
    enabled. It reflects the consensus reached in a discussion a while ago.

    Signed-off-by: Maciej W. Rozycki
    Cc: Jiri Slaby
    Cc: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     

21 Jul, 2008

1 commit


28 Apr, 2008

1 commit


08 Feb, 2008

9 commits

  • This is a set of changes to implement proper resource management in the
    driver, including iomem space reservation and operating on physical
    addresses ioremap()ped appropriately using accessory functions rather than
    unportable direct assignments.

    Some adjustments to code are made to reflect the architecture of the
    interface, which is a centrally controlled multiport (or, as referred to
    from DEC documentation, a serial line multiplexer, going up to 8 lines
    originally) rather than a bundle of separate ports.

    Types are changed, where applicable, to specify the width of hardware
    registers explicitly. The interrupt handler is now managed in the
    ->startup() and ->shutdown() calls for consistency with other drivers and
    also in preparation to handle the handover from the initial firmware-based
    console gracefully.

    Signed-off-by: Maciej W. Rozycki
    Cc: Ralf Baechle
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • Replace all casts from "struct uart_port *" to "struct dz_port *" with a
    construct based on container_of(). This makes the conversion work
    irrespective of where the former struct is located within the latter.

    By popular request I have implemented it as an inline function rather than
    a macro this time.

    Signed-off-by: Maciej W. Rozycki
    Cc: Ralf Baechle
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • A set of changes to the way termios settings are propagated to the serial
    port hardware. The DZ11 only supports a selection of fixed baud settings,
    so some requests may not be fulfilled. Keep the old setting in such a case
    and failing that resort to 9600bps. Also add a missing update of the
    transmit timeout. And remove the explicit encoding of the line selected
    from writes to the Line Parameters Register as it has been preencoded by
    the ->set_termios() call already. Finally, remove a duplicate macro for
    the Receiver Enable bit.

    Signed-off-by: Maciej W. Rozycki
    Cc: Ralf Baechle
    Cc: Alan Cox
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • Handle the read and ignore status masks correctly. Handle the BREAK condition
    as expected: a framing error with a null character is a BREAK, any other
    framing error is a framing error indeed.

    Signed-off-by: Maciej W. Rozycki
    Cc: Jiri Slaby
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • The ->start_tx(), ->stop_tx() and ->stop_rx() backends are called with the
    port's lock already taken. Remove locking from within them and wrap around
    calls as necessary.

    Signed-off-by: Maciej W. Rozycki
    Cc: Jiri Slaby
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • Rename the serial console structure so that `modpost' does not complain about
    a reference to an "init" section -- "_console" is magic.

    Signed-off-by: Maciej W. Rozycki
    Cc: Jiri Slaby
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • Sort the header inclusions, add a few that are needed but pulled indirectly
    only and remove ones that are not really used.

    Signed-off-by: Maciej W. Rozycki
    Cc: Jiri Slaby
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • Well, panic() is a little bit undue if request_irq() fails; there is probably
    no need to justify it any further. Handle the case gracefully, by
    unregistering the driver.

    Signed-off-by: Maciej W. Rozycki
    Cc: Jiri Slaby
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     
  • Polled transmission is tricky enough with the DZ11 design. While "loop" is
    set to a high value, conceptually you are not allowed to transmit without
    checking whether the device offers the right transmission line (yes, it is the
    device that selects the line -- the driver has no control over it other than
    disabling the transmitter offered if it is the wrong one), so the loop has to
    be run at least once.

    Well, the '1977 or PDP11 view of how serial lines should be handled... Except
    that the serial interface used to be quite an impressive board back then
    rather than chip.

    Signed-off-by: Maciej W. Rozycki
    Cc: Jiri Slaby
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     

07 Feb, 2008

1 commit

  • Mostly in and around irq handlers.

    Signed-off-by: Jeff Garzik
    Cc: Russell King
    Cc: "Luck Tony"
    Cc: Roman Zippel
    Cc: Geert Uytterhoeven
    Cc: Paul Mackerras
    Cc: Benjamin Herrenschmidt
    Acked-by: Dmitry Torokhov
    Cc: Karsten Keil
    Acked-by: "John W. Linville"
    Cc: James Bottomley
    Cc: David Brownell
    Cc: "Antonino A. Daplas"
    Acked-by: Josh Boyer
    Acked-by: Holger Schurig
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Jeff Garzik
     

05 Mar, 2007

1 commit


09 Dec, 2006

1 commit

  • 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

1 commit

  • This a set of fixes mostly to make the driver actually work:

    1. Actually select the line for setting parameters and receiver
    disable/enable.
    2. Select the line for receive and transmit interrupt handling correctly.
    3. Report the transmitter empty state correctly.
    4. Set the I/O type of ports correctly.
    5. Perform polled transmission correctly.
    6. Don't fix the console line at ttyS3.
    7. Magic SysRq support.
    8. Various small bits here and there.

    Tested with a DECstation 2100 (thanks Flo for making this possible).

    [akpm@osdl.org: fix typo]
    Signed-off-by: Maciej W. Rozycki
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Maciej W. Rozycki
     

05 Oct, 2006

1 commit

  • Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
    of passing regs around manually through all ~1800 interrupt handlers in the
    Linux kernel.

    The regs pointer is used in few places, but it potentially costs both stack
    space and code to pass it around. On the FRV arch, removing the regs parameter
    from all the genirq function results in a 20% speed up of the IRQ exit path
    (ie: from leaving timer_interrupt() to leaving do_IRQ()).

    Where appropriate, an arch may override the generic storage facility and do
    something different with the variable. On FRV, for instance, the address is
    maintained in GR28 at all times inside the kernel as part of general exception
    handling.

    Having looked over the code, it appears that the parameter may be handed down
    through up to twenty or so layers of functions. Consider a USB character
    device attached to a USB hub, attached to a USB controller that posts its
    interrupts through a cascaded auxiliary interrupt controller. A character
    device driver may want to pass regs to the sysrq handler through the input
    layer which adds another few layers of parameter passing.

    I've build this code with allyesconfig for x86_64 and i386. I've runtested the
    main part of the code on FRV and i386, though I can't test most of the drivers.
    I've also done partial conversion for powerpc and MIPS - these at least compile
    with minimal configurations.

    This will affect all archs. Mostly the changes should be relatively easy.
    Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

    struct pt_regs *old_regs = set_irq_regs(regs);

    And put the old one back at the end:

    set_irq_regs(old_regs);

    Don't pass regs through to generic_handle_irq() or __do_IRQ().

    In timer_interrupt(), this sort of change will be necessary:

    - update_process_times(user_mode(regs));
    - profile_tick(CPU_PROFILING, regs);
    + update_process_times(user_mode(get_irq_regs()));
    + profile_tick(CPU_PROFILING);

    I'd like to move update_process_times()'s use of get_irq_regs() into itself,
    except that i386, alone of the archs, uses something other than user_mode().

    Some notes on the interrupt handling in the drivers:

    (*) input_dev() is now gone entirely. The regs pointer is no longer stored in
    the input_dev struct.

    (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking. It does
    something different depending on whether it's been supplied with a regs
    pointer or not.

    (*) Various IRQ handler function pointers have been moved to type
    irq_handler_t.

    Signed-Off-By: David Howells
    (cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)

    David Howells
     

10 Jul, 2006

1 commit

  • Fix the following compilation error in the dz serial driver that got
    introduced with the "kernel console should send CRLF not LFCR" change.

    CC drivers/serial/dz.o
    drivers/serial/dz.c: In function 'dz_console_putchar':
    drivers/serial/dz.c:679: error: 'uport' undeclared (first use in this function)
    drivers/serial/dz.c:679: error: (Each undeclared identifier is reported only once
    drivers/serial/dz.c:679: error: for each function it appears in.)

    Signed-off-by: Martin Michlmayr
    Signed-off-by: Russell King

    Martin Michlmayr
     

03 Jul, 2006

1 commit


01 Jul, 2006

1 commit


27 Jun, 2006

1 commit


21 Mar, 2006

1 commit

  • Glen Turner reported that writing LFCR rather than the more
    traditional CRLF causes issues with some terminals.

    Since this aflicts many serial drivers, extract the common code
    to a library function (uart_console_write) and arrange for each
    driver to supply a "putchar" function.

    Signed-off-by: Russell King

    Russell King
     

09 Feb, 2006

1 commit


05 Feb, 2006

1 commit


11 Jan, 2006

1 commit

  • 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
     

13 Nov, 2005

2 commits


31 Aug, 2005

1 commit

  • 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

  • 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