27 Nov, 2012

1 commit


30 Jul, 2012

2 commits

  • This patch adds dma_get_sgtable() function which is required to let
    drivers to share the buffers allocated by DMA-mapping subsystem. Right
    now the driver gets a dma address of the allocated buffer and the kernel
    virtual mapping for it. If it wants to share it with other device (= map
    into its dma address space) it usually hacks around kernel virtual
    addresses to get pointers to pages or assumes that both devices share
    the DMA address space. Both solutions are just hacks for the special
    cases, which should be avoided in the final version of buffer sharing.

    To solve this issue in a generic way, a new call to DMA mapping has been
    introduced - dma_get_sgtable(). It allocates a scatter-list which
    describes the allocated buffer and lets the driver(s) to use it with
    other device(s) by calling dma_map_sg() on it.

    This patch provides a generic implementation based on virt_to_page()
    call. Architectures which require more sophisticated translation might
    provide their own get_sgtable() methods.

    Signed-off-by: Marek Szyprowski
    Reviewed-by: Kyungmin Park
    Reviewed-by: Daniel Vetter

    Marek Szyprowski
     
  • Commit 9adc5374 ('common: dma-mapping: introduce mmap method') added a
    generic method for implementing mmap user call to dma_map_ops structure.

    This patch converts ARM and PowerPC architectures (the only providers of
    dma_mmap_coherent/dma_mmap_writecombine calls) to use this generic
    dma_map_ops based call and adds a generic cross architecture
    definition for dma_mmap_attrs, dma_mmap_coherent, dma_mmap_writecombine
    functions.

    The generic mmap virt_to_page-based fallback implementation is provided for
    architectures which don't provide their own implementation for mmap method.

    Signed-off-by: Marek Szyprowski
    Reviewed-by: Kyungmin Park

    Marek Szyprowski
     

01 Nov, 2011

1 commit


30 Mar, 2010

1 commit

  • …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

10 Feb, 2007

1 commit

  • Implement device resource management, in short, devres. A device
    driver can allocate arbirary size of devres data which is associated
    with a release function. On driver detach, release function is
    invoked on the devres data, then, devres data is freed.

    devreses are typed by associated release functions. Some devreses are
    better represented by single instance of the type while others need
    multiple instances sharing the same release function. Both usages are
    supported.

    devreses can be grouped using devres group such that a device driver
    can easily release acquired resources halfway through initialization
    or selectively release resources (e.g. resources for port 1 out of 4
    ports).

    This patch adds devres core including documentation and the following
    managed interfaces.

    * alloc/free : devm_kzalloc(), devm_kzfree()
    * IO region : devm_request_region(), devm_release_region()
    * IRQ : devm_request_irq(), devm_free_irq()
    * DMA : dmam_alloc_coherent(), dmam_free_coherent(),
    dmam_declare_coherent_memory(), dmam_pool_create(),
    dmam_pool_destroy()
    * PCI : pcim_enable_device(), pcim_pin_device(), pci_is_managed()
    * iomap : devm_ioport_map(), devm_ioport_unmap(), devm_ioremap(),
    devm_ioremap_nocache(), devm_iounmap(), pcim_iomap_table(),
    pcim_iomap(), pcim_iounmap()

    Signed-off-by: Tejun Heo
    Signed-off-by: Jeff Garzik

    Tejun Heo