xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

ARM: 8256/1: driver coamba: add device binding path 'driver_override'

Browse Source 
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>
This commit is contained in:
Antonios Motakis
2015-01-06 11:15:11 +01:00
committed by Russell King
parent 8684014d71
commit 3cf3857134
3 changed files with 68 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
Documentation/ABI/testing/sysfs-bus-amba Normal file
View File

@@ -0,0 +1,20 @@
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.