uio: add generic driver for PCI 2.3 devices

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>

1 files changed, 10 insertions, 0 deletions

diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
index 45200fd6853..8aa1955f35e 100644
--- a/drivers/uio/Kconfig
+++ b/drivers/uio/Kconfig
@@ -84,4 +84,14 @@ config UIO_SERCOS3
 
           If you compile this as a module, it will be called uio_sercos3.
 
+config UIO_PCI_GENERIC
+        tristate "Generic driver for PCI 2.3 and PCI Express cards"
+        depends on PCI
+        default n
+        help
+          Generic driver that you can bind, dynamically, to any
+          PCI 2.3 compliant and PCI Express card. It is useful,
+          primarily, for virtualization scenarios.
+          If you compile this as a module, it will be called uio_pci_generic.
+
 endif