usb_drv error -92 for RPi | Genode 18.05 with Fiasco.OC 79

[Sebastian Sumpf]

Hello Tomasz,

On 4/15/19 9:42 AM, Christian Helmuth wrote:
> Hello Tomasz,
> 
> On Sat, Apr 13, 2019 at 18:40:59 CEST, Tomasz Gajewski wrote:
>> On rpi3 (and others) there is a difference between bus addresses and
>> physical addresses. In [1] I made a "brutal" fix working for
>> rpi3. It is definitely not the final one as it is not just for rpi.
> 
> Great finding! I instantly had a look into the BCM2835/7 ARM
> Peripherals manuals and it seems the 0x40000000 bus address range is
> specified as L2-cache coherent alias of the first 256 MiB SDRAM, which
> are also mapped uncached to bus address 0xc0000000.
> 
> Do you agree that from this specification 0xc0000000 should also work
> for DMA-based devices on Rpi1?
> 

great findings. I didn't know about address ranges on Rpi's and
definitely will have a look at them when fixing issue 3247 [1].

Thanks,

Sebastian

[1] https://github.com/genodelabs/genode/issues/3247



-- 
Sebastian Sumpf
Genode Labs

http://www.genode-labs.com · http://genode.org

Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth