02 May, 2015

1 commit

  • This patch adds a new OF-friendly API of_hwspin_lock_get_id()
    for hwspinlock clients to use/request locks from a hwspinlock
    device instantiated through a device-tree blob. This new API
    can be used by hwspinlock clients to get the id for a specific
    lock using the phandle + args specifier, so that it can be
    requested using the available hwspin_lock_request_specific()
    API.

    Signed-off-by: Suman Anna
    Reviewed-by: Bjorn Andersson
    [small comment clarification]
    Signed-off-by: Ohad Ben-Cohen

    Suman Anna
     

16 Mar, 2012

1 commit

  • The header includes a lot of stuff, and
    it in turn gets a lot of use just for the basic "struct device"
    which appears so often.

    Clean up the users as follows:

    1) For those headers only needing "struct device" as a pointer
    in fcn args, replace the include with exactly that.

    2) For headers not really using anything from device.h, simply
    delete the include altogether.

    3) For headers relying on getting device.h implicitly before
    being included themselves, now explicitly include device.h

    4) For files in which doing #1 or #2 uncovers an implicit
    dependency on some other header, fix by explicitly adding
    the required header(s).

    Any C files that were implicitly relying on device.h to be
    present have already been dealt with in advance.

    Total removals from #1 and #2: 51. Total additions coming
    from #3: 9. Total other implicit dependencies from #4: 7.

    As of 3.3-rc1, there were 110, so a net removal of 42 gives
    about a 38% reduction in device.h presence in include/*

    Signed-off-by: Paul Gortmaker

    Paul Gortmaker
     

08 Nov, 2011

1 commit

  • Fix below build warning:

    CC arch/arm/mach-omap2/hwspinlock.o
    In file included from arch/arm/mach-omap2/hwspinlock.c:22:
    include/linux/hwspinlock.h: In function '__hwspin_unlock':
    include/linux/hwspinlock.h:121: warning: 'return' with a value, in function returning void

    Signed-off-by: Axel Lin
    Signed-off-by: Ohad Ben-Cohen

    Axel Lin
     

22 Sep, 2011

3 commits

  • Hardware Spinlock devices usually contain numerous locks (known
    devices today support between 32 to 256 locks).

    Originally hwspinlock core required drivers to register (and later,
    when needed, unregister) each lock separately.

    That worked, but required hwspinlocks drivers to do a bit extra work
    when they were probed/removed.

    This patch changes hwspin_lock_{un}register() to allow a bank of
    hwspinlocks to be {un}registered in a single invocation.

    A new 'struct hwspinlock_device', which contains an array of 'struct
    hwspinlock's is now being passed to the core upon registration (so
    instead of wrapping each struct hwspinlock, a priv member has been added
    to allow drivers to piggyback their private data with each hwspinlock).

    While at it, several per-lock members were moved to be per-device:
    1. struct device *dev
    2. struct hwspinlock_ops *ops

    In addition, now that the array of locks is handled by the core,
    there's no reason to maintain a per-lock 'int id' member: the id of the
    lock anyway equals to its index in the bank's array plus the bank's
    base_id.
    Remove this per-lock id member too, and instead use a simple pointers
    arithmetic to derive it.

    As a result of this change, hwspinlocks drivers are now simpler and smaller
    (about %20 code reduction) and the memory footprint of the hwspinlock
    framework is reduced.

    Signed-off-by: Ohad Ben-Cohen

    Ohad Ben-Cohen
     
  • hwspinlock drivers must anyway select CONFIG_HWSPINLOCK,
    so there's no point in having register/unregister stubs.

    Removing those stubs will only make it easier for developers
    to catch CONFIG_HWSPINLOCK mis-.config-urations.

    Signed-off-by: Ohad Ben-Cohen

    Ohad Ben-Cohen
     
  • hwspinlock devices provide system-wide hardware locks that are used
    by remote processors that have no other way to achieve synchronization.

    To achieve that, each physical lock must have a system-wide id number
    that is agreed upon, otherwise remote processors can't possibly assume
    they're using the same hardware lock.

    Usually boards have a single hwspinlock device, which provides several
    hwspinlocks, and in this case, they can be trivially numbered 0 to
    (num-of-locks - 1).

    In case boards have several hwspinlocks devices, a different base id
    should be used for each hwspinlock device (they can't all use 0 as
    a starting id!).

    While this is certainly not common, it's just plain wrong to just
    silently use 0 as a base id whenever the hwspinlock driver is probed.

    This patch provides a hwspinlock_pdata structure, that boards can use
    to set a different base id for each of the hwspinlock devices they may
    have, and demonstrates how to use it with the omap hwspinlock driver.

    While we're at it, make sure the hwspinlock core prints an explicit
    error message in case an hwspinlock is registered with an id number
    that already exists; this will help users catch such base id issues.

    Reported-by: Arnd Bergmann
    Signed-off-by: Ohad Ben-Cohen
    Acked-by: Tony Lindgren

    Ohad Ben-Cohen
     

18 Feb, 2011

1 commit

  • Add a platform-independent hwspinlock framework.

    Hardware spinlock devices are needed, e.g., in order to access data
    that is shared between remote processors, that otherwise have no
    alternative mechanism to accomplish synchronization and mutual exclusion
    operations.

    Signed-off-by: Ohad Ben-Cohen
    Cc: Hari Kanigeri
    Cc: Benoit Cousson
    Cc: Kevin Hilman
    Cc: Grant Likely
    Cc: Paul Walmsley
    Cc: Russell King
    Acked-by: Arnd Bergmann
    Signed-off-by: Tony Lindgren

    Ohad Ben-Cohen