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As already demonstrated with PCI [1] and the platform bus [2], a driver_override property in sysfs can be used to bypass the id matching of a device to a AMBA driver. This can be used by VFIO to bind to any AMBA device requested by the user. [1] http://lists-archives.com/linux-kernel/28030441-pci-introduce-new-device-binding-path-using-pci_dev-driver_override.html [2] https://www.redhat.com/archives/libvir-list/2014-April/msg00382.html Signed-off-by: Antonios Motakis <a.motakis@virtualopensystems.com> Reviewed-by: Kim Phillips <kim.phillips@freescale.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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What: /sys/bus/amba/devices/.../driver_override Date: September 2014 Contact: Antonios Motakis a.motakis@virtualopensystems.com Description: This file allows the driver for a device to be specified which will override standard OF, ACPI, ID table, and name matching. When specified, only a driver with a name matching the value written to driver_override will have an opportunity to bind to the device. The override is specified by writing a string to the driver_override file (echo vfio-amba > driver_override) and may be cleared with an empty string (echo > driver_override). This returns the device to standard matching rules binding. Writing to driver_override does not automatically unbind the device from its current driver or make any attempt to automatically load the specified driver. If no driver with a matching name is currently loaded in the kernel, the device will not bind to any driver. This also allows devices to opt-out of driver binding using a driver_override name such as "none". Only a single driver may be specified in the override, there is no support for parsing delimiters.