[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen/arm: Propagate clock-frequency to DOMU if present in the DT timer node
Hi Julien, >My test was limited as I don't have a platform where CNTFRQ/CNTFRQ_EL0 is not >valid. I may have done a mistake in the code. Understood. That's why I thought it would be worthwhile posting my results :-) >> What I see is that in preinit_xen_time(), the call to dt_property_read_u32() >> returns zero. When I built Xen, I set CONFIG_DTB_FILE, and looking at the >> corresponding dts file it has a timer node with a clock-frequency property. >> I know that our bootloader also creates a DTB, though, and it looks like >> that one does *not* have a clock-frequency property in the timer node, so I >> guess Xen ends up using that one somehow. CNTFRQ on core 0 (only) is also >> set to the correct frequency, so I end up with the correct frequency in my >> Dom0 kernel anyway. > >dt_property_read_u32 returns 0 when it cannot find a property or because the >size of the value is not valid. > >The device tree provided via CONFIG_DTB_FILE will always take precedence to >the one pass by the bootloader. > >How do you set CONFIG_DTB_FILE? A simple "export CONFIG_DTB_FILE=...". >I would also look to see if by any chance the wrong device tree is set via >CONFIG_DTB_FILE. I did double-check before I posted, and everything looks right to me. I certainly could have missed something. It does look like it's *somehow* getting the DT generated by the bootloader. >You can check what is the device tree used by dumping it from DOM0. >Thought, it may be slightly different (some nodes are rewritten). You can dump >it using dtc -I fs /proc/device-tree -O dts When I do that (at a shell prompt in Dom0), the timer node does not have a clock-frequency property. So your patch isn't designed to help in this case (CNTFRQ set on core 0 only, no clock-frequency property in timer node of DT). Chris _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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