linux.git/drivers/base/dd.c, branch v2.6.21.7

devres: device resource management

2007-02-09T22:39:36+00:00

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

driver core: Change function call order in device_bind_driver().

2007-02-07T18:37:13+00:00

Change function call order in device_bind_driver().

If we create symlinks (which might fail) before adding the device to the list
we don't have to clean up afterwards (which we didn't).

Signed-off-by: Cornelia Huck 
Signed-off-by: Greg Kroah-Hartman

driver core: Don't stop probing on ->probe errors.

2007-02-07T18:37:12+00:00

Don't stop on the first ->probe error that is not -ENODEV/-ENXIO.

There might be a driver registered returning an unresonable return code, and
this stops probing completely even though it may make sense to try the next
possible driver. At worst, we may end up with an unbound device.

Signed-off-by: Cornelia Huck 
Signed-off-by: Greg Kroah-Hartman

Driver core: fix "driver" symlink timing

2006-12-01T22:51:58+00:00

Create the "driver" link before the child device may be created by
the probing logic. This makes it possible for userspace (udev), to
determine the driver property of the parent device, at the time the
child device is created.

Signed-off-by: Kay Sievers 
Signed-off-by: Greg Kroah-Hartman

Driver core: add notification of bus events

2006-12-01T22:51:58+00:00

I finally did as you suggested and added the notifier to the struct
bus_type itself. There are still problems to be expected is something
attaches to a bus type where the code can hook in different struct
device sub-classes (which is imho a big bogosity but I won't even try to
argue that case now) but it will solve nicely a number of issues I've
had so far.

That also means that clients interested in registering for such
notifications have to do it before devices are added and after bus types
are registered. Fortunately, most bus types that matter for the various
usage scenarios I have in mind are registerd at postcore_initcall time,
which means I have a really nice spot at arch_initcall time to add my
notifiers.

There are 4 notifications provided. Device being added (before hooked to
the bus) and removed (failure of previous case or after being unhooked
from the bus), along with driver being bound to a device and about to be
unbound.

The usage I have for these are:

 - The 2 first ones are used to maintain a struct device_ext that is
hooked to struct device.firmware_data. This structure contains for now a
pointer to the Open Firmware node related to the device (if any), the
NUMA node ID (for quick access to it) and the DMA operations pointers &
iommu table instance for DMA to/from this device. For bus types I own
(like IBM VIO or EBUS), I just maintain that structure directly from the
bus code when creating the devices. But for bus types managed by generic
code like PCI or platform (actually, of_platform which is a variation of
platform linked to Open Firmware device-tree), I need this notifier.

 - The other two ones have a completely different usage scenario. I have
cases where multiple devices and their drivers depend on each other. For
example, the IBM EMAC network driver needs to attach to a MAL DMA engine
which is a separate device, and a PHY interface which is also a separate
device. They are all of_platform_device's (well, about to be with my
upcoming patches) but there is no say in what precise order the core
will "probe" them and instanciate the various modules. The solution I
found for that is to have the drivers for emac to use multithread_probe,
and wait for a driver to be bound to the target MAL and PHY control
devices (the device-tree contains reference to the MAL and PHY interface
nodes, which I can then match to of_platform_devices). Right now, I've
been polling, but with that notifier, I can more cleanly wait (with a
timeout of course).

Signed-off-by: Benjamin Herrenschmidt 
Signed-off-by: Greg Kroah-Hartman

[PATCH] drivers: wait for threaded probes between initcall levels

2006-10-27T22:34:51+00:00

The multithreaded-probing code has a problem: after one initcall level (eg,
core_initcall) has been processed, we will then start processing the next
level (postcore_initcall) while the kernel threads which are handling
core_initcall are still executing.  This breaks the guarantees which the
layered initcalls previously gave us.

IOW, we want to be multithreaded _within_ an initcall level, but not between
different levels.

Fix that up by causing the probing code to wait for all outstanding probes at
one level to complete before we start processing the next level.

Cc: Greg KH 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

driver core: kmalloc() failure check in driver_probe_device

2006-10-18T19:49:56+00:00

driver_probe_device() is missing kmalloc() failure check.

Signed-off-by: Akinobu Mita 
Signed-off-by: Greg Kroah-Hartman

Driver core: plug device probe memory leak

2006-10-18T19:49:54+00:00

Make sure data is freed if the kthread fails to start.

Signed-off-by: Duncan Sands 
Signed-off-by: Greg Kroah-Hartman

Driver core: Fix potential deadlock in driver core

2006-09-26T04:08:40+00:00

There is a potential deadlock in the driver core.  It boils down to
the fact that bus_remove_device() calls klist_remove() instead of
klist_del(), thereby waiting until the reference count of the
klist_node in the bus's klist of devices drops to 0.  The refcount
can't reach 0 so long as a modprobe process is trying to bind a new
driver to the device being removed, by calling __driver_attach().  The
problem is that __driver_attach() tries to acquire the device's
parent's semaphore, but the caller of bus_remove_device() is quite
likely to own that semaphore already.

It isn't sufficient just to replace klist_remove() with klist_del().
Doing so runs the risk that the device would remain on the bus's klist
of devices for some time, and so could be bound to another driver even
after it was unregistered.  What's needed is a new way to distinguish
whether or not a device is registered, based on a criterion other than
whether its klist_node is linked into the bus's klist of devices.  That
way driver binding can fail when the device is unregistered, even if
it is still linked into the klist.

This patch (as782) implements the solution, by adding a new bitflag to
indiate when a struct device is registered, by testing the flag before
allowing a driver to bind a device, and by changing the definition of
the device_is_registered() inline.

Signed-off-by: Alan Stern 
Signed-off-by: Greg Kroah-Hartman

Driver Core: add ability for drivers to do a threaded probe

2006-09-26T04:08:40+00:00

This adds the infrastructure for drivers to do a threaded probe, and
waits at init time for all currently outstanding probes to complete.

A new kernel thread will be created when the probe() function for the
driver is called, if the multithread_probe bit is set in the driver
saying it can support this kind of operation.

I have tested this with USB and PCI, and it works, and shaves off a lot
of time in the boot process, but there are issues with finding root boot
disks, and some USB drivers assume that this can never happen, so it is
currently not enabled for any bus type.  Individual drivers can enable
this right now if they wish, and bus authors can selectivly turn it on
as well, once they determine that their subsystem will work properly
with it.

Signed-off-by: Greg Kroah-Hartman