24 Jul, 2011

1 commit


23 Jul, 2011

1 commit

  • There are many places in the tree where we implement register access for
    devices on non-memory mapped buses, especially I2C and SPI. Since hardware
    designers seem to have settled on a relatively consistent set of register
    interfaces this can be effectively factored out into shared code. There
    are a standard set of formats for marshalling data for exchange with the
    device, with the actual I/O mechanisms generally being simple byte
    streams.

    We create an abstraction for marshaling data into formats which can be
    sent on the control interfaces, and create a standard method for
    plugging in actual transport underneath that.

    This is mostly a refactoring and renaming of the bottom level of the
    existing code for sharing register I/O which we have in ASoC. A
    subsequent patch in this series converts ASoC to use this. The main
    difference in interface is that reads return values by writing to a
    location provided by a pointer rather than in the return value, ensuring
    we can use the full range of the type for register data. We also use
    unsigned types rather than ints for the same reason.

    As some of the devices can have very large register maps the existing
    ASoC code also contains infrastructure for managing register caches.
    This cache work will be moved over in a future stage to allow for
    separate review, the current patch only deals with the physical I/O.

    Signed-off-by: Mark Brown
    Acked-by: Liam Girdwood
    Acked-by: Greg Kroah-Hartman
    Acked-by: Wolfram Sang
    Acked-by: Grant Likely

    Mark Brown
     

14 Jun, 2011

1 commit

  • Create a dedicated folder for iommu drivers, and move the base
    iommu implementation over there.

    Grouping the various iommu drivers in a single location will help
    finding similar problems shared by different platforms, so they
    could be solved once, in the iommu framework, instead of solved
    differently (or duplicated) in each driver.

    Signed-off-by: Ohad Ben-Cohen
    Signed-off-by: Joerg Roedel

    Ohad Ben-Cohen
     

15 Mar, 2011

1 commit

  • Some subsystems need to carry out suspend/resume and shutdown
    operations with one CPU on-line and interrupts disabled. The only
    way to register such operations is to define a sysdev class and
    a sysdev specifically for this purpose which is cumbersome and
    inefficient. Moreover, the arguments taken by sysdev suspend,
    resume and shutdown callbacks are practically never necessary.

    For this reason, introduce a simpler interface allowing subsystems
    to register operations to be executed very late during system suspend
    and shutdown and very early during resume in the form of
    strcut syscore_ops objects.

    Signed-off-by: Rafael J. Wysocki
    Acked-by: Greg Kroah-Hartman

    Rafael J. Wysocki
     

23 Oct, 2010

1 commit


16 Sep, 2009

2 commits

  • Devtmpfs lets the kernel create a tmpfs instance called devtmpfs
    very early at kernel initialization, before any driver-core device
    is registered. Every device with a major/minor will provide a
    device node in devtmpfs.

    Devtmpfs can be changed and altered by userspace at any time,
    and in any way needed - just like today's udev-mounted tmpfs.
    Unmodified udev versions will run just fine on top of it, and will
    recognize an already existing kernel-created device node and use it.
    The default node permissions are root:root 0600. Proper permissions
    and user/group ownership, meaningful symlinks, all other policy still
    needs to be applied by userspace.

    If a node is created by devtmps, devtmpfs will remove the device node
    when the device goes away. If the device node was created by
    userspace, or the devtmpfs created node was replaced by userspace, it
    will no longer be removed by devtmpfs.

    If it is requested to auto-mount it, it makes init=/bin/sh work
    without any further userspace support. /dev will be fully populated
    and dynamic, and always reflect the current device state of the kernel.
    With the commonly used dynamic device numbers, it solves the problem
    where static devices nodes may point to the wrong devices.

    It is intended to make the initial bootup logic simpler and more robust,
    by de-coupling the creation of the inital environment, to reliably run
    userspace processes, from a complex userspace bootstrap logic to provide
    a working /dev.

    Signed-off-by: Kay Sievers
    Signed-off-by: Jan Blunck
    Tested-By: Harald Hoyer
    Tested-By: Scott James Remnant
    Signed-off-by: Greg Kroah-Hartman

    Kay Sievers
     
  • Placing dma-coherent.c in driver/base is better than in kernel,
    since it contains code to do per-device coherent dma memory
    handling.

    Signed-off-by: Ming Lei
    Signed-off-by: Greg Kroah-Hartman

    Ming Lei
     

03 Jan, 2009

1 commit


06 Feb, 2008

1 commit


25 Jan, 2008

2 commits

  • When SYSFS=n and MODULES=y, build ends with:

    linux-2.6.24-rc6-mm1/drivers/base/module.c: In function 'module_add_driver':
    linux-2.6.24-rc6-mm1/drivers/base/module.c:49: error: 'module_kset' undeclared (first use in this function)
    make[3]: *** [drivers/base/module.o] Error 1

    Below is one possible fix.
    Build-tested with all 4 config combinations of SYSFS & MODULES.

    Signed-off-by: Randy Dunlap
    Signed-off-by: Greg Kroah-Hartman

    Randy Dunlap
     
  • The module driver specific code should belong in the driver core, not in
    the kernel/ directory. So move this code. This is done in preparation
    for some struct device_driver rework that should be confined to the
    driver core code only.

    This also lets us keep from exporting these functions, as no external
    code should ever be calling it.

    Thanks to Andrew Morton for the !CONFIG_MODULES fix.

    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

04 Dec, 2007

1 commit


08 May, 2007

1 commit

  • Architectures that don't support DMA can say so by adding a config NO_DMA
    to their Kconfig file. This will prevent compilation of some dma specific
    driver code. Also dma-mapping-broken.h isn't needed anymore on at least
    s390. This avoids compilation and linking of otherwise dead/broken code.

    Other architectures that include dma-mapping-broken.h are arm26, h8300,
    m68k, m68knommu and v850. If these could be converted as well we could get
    rid of the header file.

    Signed-off-by: Heiko Carstens
    "John W. Linville"
    Cc: Kyle McMartin
    Cc:
    Cc: Tejun Heo
    Cc: Jeff Garzik
    Cc: Martin Schwidefsky
    Cc:
    Cc:
    Cc:
    Cc:
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Heiko Carstens
     

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
     

01 Oct, 2006

1 commit


22 Jun, 2006

2 commits

  • During the recent "isa drivers using platform devices" discussion it was
    pointed out that (ALSA) ISA drivers ran into the problem of not having
    the option to fail driver load (device registration rather) upon not
    finding their hardware due to a probe() error not being passed up
    through the driver model. In the course of that, I suggested a seperate
    ISA bus might be best; Russell King agreed and suggested this bus could
    use the .match() method for the actual device discovery.

    The attached does this. For this old non (generically) discoverable ISA
    hardware only the driver itself can do discovery so as a difference with
    the platform_bus, this isa_bus also distributes match() up to the driver.

    As another difference: these devices only exist in the driver model due
    to the driver creating them because it might want to drive them, meaning
    that all device creation has been made internal as well.

    The usage model this provides is nice, and has been acked from the ALSA
    side by Takashi Iwai and Jaroslav Kysela. The ALSA driver module_init's
    now (for oldisa-only drivers) become:

    static int __init alsa_card_foo_init(void)
    {
    return isa_register_driver(&snd_foo_isa_driver, SNDRV_CARDS);
    }

    static void __exit alsa_card_foo_exit(void)
    {
    isa_unregister_driver(&snd_foo_isa_driver);
    }

    Quite like the other bus models therefore. This removes a lot of
    duplicated init code from the ALSA ISA drivers.

    The passed in isa_driver struct is the regular driver struct embedding a
    struct device_driver, the normal probe/remove/shutdown/suspend/resume
    callbacks, and as indicated that .match callback.

    The "SNDRV_CARDS" you see being passed in is a "unsigned int ndev"
    parameter, indicating how many devices to create and call our methods with.

    The platform_driver callbacks are called with a platform_device param;
    the isa_driver callbacks are being called with a "struct device *dev,
    unsigned int id" pair directly -- with the device creation completely
    internal to the bus it's much cleaner to not leak isa_dev's by passing
    them in at all. The id is the only thing we ever want other then the
    struct device * anyways, and it makes for nicer code in the callbacks as
    well.

    With this additional .match() callback ISA drivers have all options. If
    ALSA would want to keep the old non-load behaviour, it could stick all
    of the old .probe in .match, which would only keep them registered after
    everything was found to be present and accounted for. If it wanted the
    behaviour of always loading as it inadvertently did for a bit after the
    changeover to platform devices, it could just not provide a .match() and
    do everything in .probe() as before.

    If it, as Takashi Iwai already suggested earlier as a way of following
    the model from saner buses more closely, wants to load when a later bind
    could conceivably succeed, it could use .match() for the prerequisites
    (such as checking the user wants the card enabled and that port/irq/dma
    values have been passed in) and .probe() for everything else. This is
    the nicest model.

    To the code...

    This exports only two functions; isa_{,un}register_driver().

    isa_register_driver() register's the struct device_driver, and then
    loops over the passed in ndev creating devices and registering them.
    This causes the bus match method to be called for them, which is:

    int isa_bus_match(struct device *dev, struct device_driver *driver)
    {
    struct isa_driver *isa_driver = to_isa_driver(driver);

    if (dev->platform_data == isa_driver) {
    if (!isa_driver->match ||
    isa_driver->match(dev, to_isa_dev(dev)->id))
    return 1;
    dev->platform_data = NULL;
    }
    return 0;
    }

    The first thing this does is check if this device is in fact one of this
    driver's devices by seeing if the device's platform_data pointer is set
    to this driver. Platform devices compare strings, but we don't need to
    do that with everything being internal, so isa_register_driver() abuses
    dev->platform_data as a isa_driver pointer which we can then check here.
    I believe platform_data is available for this, but if rather not, moving
    the isa_driver pointer to the private struct isa_dev is ofcourse fine as
    well.

    Then, if the the driver did not provide a .match, it matches. If it did,
    the driver match() method is called to determine a match.

    If it did _not_ match, dev->platform_data is reset to indicate this to
    isa_register_driver which can then unregister the device again.

    If during all this, there's any error, or no devices matched at all
    everything is backed out again and the error, or -ENODEV, is returned.

    isa_unregister_driver() just unregisters the matched devices and the
    driver itself.

    More global points/questions...

    - I'm introducing include/linux/isa.h. It was available but is ofcourse
    a somewhat generic name. Moving more isa stuff over to it in time is
    ofcourse fine, so can I have it please? :)

    - I'm using device_initcall() and added the isa.o (dependent on
    CONFIG_ISA) after the base driver model things in the Makefile. Will
    this do, or I really need to stick it in drivers/base/init.c, inside
    #ifdef CONFIG_ISA? It's working fine.

    Lastly -- I also looked, a bit, into integrating with PnP. "Old ISA"
    could be another pnp_protocol, but this does not seem to be a good
    match, largely due to the same reason platform_devices weren't -- the
    devices do not have a life of their own outside the driver, meaning the
    pnp_protocol {get,set}_resources callbacks would need to callback into
    driver -- which again means you first need to _have_ that driver. Even
    if there's clean way around that, you only end up inventing fake but
    valid-form PnP IDs and generally catering to the PnP layer without any
    practical advantages over this very simple isa_bus. The thing I also
    suggested earlier about the user echoing values into /sys to set up the
    hardware from userspace first is... well, cute, but a horrible idea from
    a user standpoint.

    Comments ofcourse appreciated. Hope it's okay. As said, the usage model
    is nice at least.

    Signed-off-by: Rene Herman

    Rene Herman
     
  • To have a home for all hypervisors, this patch creates /sys/hypervisor.
    A new config option SYS_HYPERVISOR is introduced, which should to be set
    by architecture dependent hypervisors (e.g. s390 or Xen).

    Acked-by: Martin Schwidefsky
    Signed-off-by: Michael Holzheu
    Signed-off-by: Greg Kroah-Hartman

    Michael Holzheu
     

04 Feb, 2006

1 commit

  • The patch implements cpu topology exportation by sysfs.

    Items (attributes) are similar to /proc/cpuinfo.

    1) /sys/devices/system/cpu/cpuX/topology/physical_package_id:
    represent the physical package id of cpu X;
    2) /sys/devices/system/cpu/cpuX/topology/core_id:
    represent the cpu core id to cpu X;
    3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
    represent the thread siblings to cpu X in the same core;
    4) /sys/devices/system/cpu/cpuX/topology/core_siblings:
    represent the thread siblings to cpu X in the same physical package;

    To implement it in an architecture-neutral way, a new source file,
    driver/base/topology.c, is to export the 5 attributes.

    If one architecture wants to support this feature, it just needs to
    implement 4 defines, typically in file include/asm-XXX/topology.h.
    The 4 defines are:
    #define topology_physical_package_id(cpu)
    #define topology_core_id(cpu)
    #define topology_thread_siblings(cpu)
    #define topology_core_siblings(cpu)

    The type of **_id is int.
    The type of siblings is cpumask_t.

    To be consistent on all architectures, the 4 attributes should have
    deafult values if their values are unavailable. Below is the rule.

    1) physical_package_id: If cpu has no physical package id, -1 is the
    default value.

    2) core_id: If cpu doesn't support multi-core, its core id is 0.

    3) thread_siblings: Just include itself, if the cpu doesn't support
    HT/multi-thread.

    4) core_siblings: Just include itself, if the cpu doesn't support
    multi-core and HT/Multi-thread.

    So be careful when declaring the 4 defines in include/asm-XXX/topology.h.

    If an attribute isn't defined on an architecture, it won't be exported.

    Thank Nathan, Greg, Andi, Paul and Venki.

    The patch provides defines for i386/x86_64/ia64.

    Signed-off-by: Zhang, Yanmin
    Cc: Ingo Molnar
    Cc: Nick Piggin
    Cc: Greg KH
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Zhang, Yanmin
     

30 Oct, 2005

1 commit

  • This adds generic memory add/remove and supporting functions for memory
    hotplug into a new file as well as a memory hotplug kernel config option.

    Individual architecture patches will follow.

    For now, disable memory hotplug when swsusp is enabled. There's a lot of
    churn there right now. We'll fix it up properly once it calms down.

    Signed-off-by: Matt Tolentino
    Signed-off-by: Dave Hansen
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Dave Hansen
     

21 Jun, 2005

2 commits


18 May, 2005

1 commit

  • The driver model has a "detach_state" mechanism that:

    - Has never been used by any in-kernel drive;
    - Is superfluous, since driver remove() methods can do the same thing;
    - Became buggy when the suspend() parameter changed semantics and type;
    - Could self-deadlock when called from certain suspend contexts;
    - Is effectively wasted documentation, object code, and headspace.

    This removes that "detach_state" mechanism; net code shrink, as well
    as a per-device saving in the driver model and sysfs.

    Signed-off-by: David Brownell
    Signed-off-by: Greg Kroah-Hartman

    David Brownell
     

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