This adds a generic uio driver that can bind to any PCI device. First
user will be virtualization where a qemu userspace process needs to give
guest OS access to the device.
Interrupts are handled using the Interrupt Disable bit in the PCI
command register and Interrupt Status bit in the PCI status register.
All devices compliant to PCI 2.3 (circa 2002) and all compliant PCI
Express devices should support these bits. Driver detects this support,
and won't bind to devices which do not support the Interrupt Disable Bit
in the command register.
It's expected that more features of interest to virtualization will be
added to this driver in the future. Possibilities are: mmap for device
resources, MSI/MSI-X, eventfd (to interface with kvm), iommu.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Chris Wright <chrisw@redhat.com>
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
If a UIO device has several memory mappings, it can be difficult for userspace
to find the right one. The situation becomes even worse if the UIO driver can
handle different versions of a card that have different numbers of mappings.
Benedikt Spranger has such cards and pointed this out to me. Thanks, Bene!
To address this problem, this patch adds "name" sysfs attributes for each
mapping. Userspace can use these to clearly identify each mapping. The name
string is optional. If a driver doesn't set it, an empty string will be
returned, so this patch won't break existing drivers.
The same problem exists for port region information, so a "name" attribute is
added there, too.
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The following features were added to the UIO framework in the near past:
* Generic drivers for platform devices (uio_pdrv, uio_pdrv_genirq)
* an "offset" sysfs attribute for memory mappings
Unfortunately, all this went in without documentation (won't happen again...)
This patch updates UIO documentation.
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Acked-by: Uwe Kleine-König <ukleinek@strlen.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
These are only ever assigned constant strings and never modified.
This was noticed because Wolfram Sang needed to cast the result of
of_get_property() in order to assign it to the name field of a struct
uio_info.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This patch updates UIO documentation with the changes introduced by
previous UIO patch.
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The Userspace I/O HOWTO template sets two different sections with the same
html output name (about.html). This clearly won't work, so change the
first one to a unique "aboutthis.html" to prevent clobbering.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Hans J. Koch <hjk@linutronix.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
The Userspace I/O HOWTO document uses straight <sect1> tags and plain text
to describe copyright/legal information. It should instead use the
<copyright> and <legalnotice> tags like all other documents in the kernel.
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Hans J. Koch <hjk@linutronix.de>
Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Sometimes it is necessary to enable/disable the interrupt of a UIO device
from the userspace part of the driver. With this patch, the UIO kernel driver
can implement an "irqcontrol()" function that does this. Userspace can write
an s32 value to /dev/uioX (usually 0 or 1 to turn the irq off or on). The
UIO core will then call the driver's irqcontrol function.
Signed-off-by: Hans J. Koch <hjk@linutronix.de>
Acked-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
Acked-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Remove references to the old uio_dummy demo module from UIO documentation.
Add a small paragraph to make it clearer that UIO is not a universal driver
interface.
Signed-off-by: Hans J Koch <hjk@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
UIO currently contains a rather dubious statement which wants removing.
The actual questions around whether user space code that depends tightly
on kernel GPL code designed to co-work with it are derivative works of
the kernel is extremely complex, and since we don't have space for either
a masters length essay on legal issues or need to start flamewars lets
simply remove the comment and leave law to lawyers
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <tovalds@linux-foundation.org>
