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SubjectRe: UIO: missing resource mapping
From
Date
Am Freitag, den 13.07.2012, 16:22 +0300 schrieb Michael S. Tsirkin:
> Could you give an example of the problem? How do you bind
> both UIO and another driver to the same device?

Sorry, I'm looking on it from the user-space perspective. Maybe I'm
wrong, but I can give you an example :

lspci -v
...
03:00.0 Network controller: Broadcom Corporation BCM4331 802.11a/b/g/n
(rev 02)
Subsystem: Apple Inc. AirPort Extreme
Flags: bus master, fast devsel, latency 0, IRQ 17
Memory at b0600000 (64-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Capabilities: [58] Vendor Specific Information: Len=78 <?>
Capabilities: [48] MSI: Enable- Count=1/1 Maskable- 64bit+
Capabilities: [d0] Express Endpoint, MSI 00
Capabilities: [100] Advanced Error Reporting
Capabilities: [13c] Virtual Channel
Capabilities: [160] Device Serial Number 85-f2-6d-ff-ff-42-68-a8
Capabilities: [16c] Power Budgeting <?>
Kernel driver in use: bcma-pci-bridge
...

This Device has one 64 Bit Bar. When I look at the related sysfs
entry ...


ls /sys/bus/pci/devices/0000:03:00.0
...
--w------- 1 root root 4.0K Jul 13 16:35 reset
-r--r--r-- 1 root root 4.0K Jul 12 21:43 resource
-rw------- 1 root root 16K Jul 13 16:35 resource0
lrwxrwxrwx 1 root root 0 Jul 12 23:41 subsystem
-> ../../../../bus/pci
...

... I can see that it should be possible to map resource0 and directly
write into a BAR which is already managed by a kernel drivers.

Moving this functionality to UIO would only generate those resource
files, if the device is handled by UIO and therefore intended to be
managed from the user-space.

--
Gruß
Dominic

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