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Re: [Xen-devel] [GSOC-2019] Problem with initializing crossbar on bb-x15 in dom0
- To: Julien Grall <Julien.Grall@xxxxxxx>, Iain Hunter <drhunter95@xxxxxxxxx>
- From: Denis Obrezkov <denisobrezkov@xxxxxxxxx>
- Date: Sat, 6 Jul 2019 18:50:25 +0200
- Autocrypt: addr=denisobrezkov@xxxxxxxxx; prefer-encrypt=mutual; keydata= mQMuBFrAxPQRCAD59CJNd5LF1VmojUBpdr/bJ2TaKC7SW4ln7+PWn+QyAJfFOVFlTRIDsAlP 65y7CacXFCXmLTACo4a7HEhRb5787kPm6rc30zpL+04uXCeTruYZi0ZnQVXOiab/qy3aMsk0 6n9hMY28TSbM9nynnlrbg9pGkb1EiFVNsowJjFSKXa3Rpogte9qxfXmLf2eV0MZNnrmq6Kb2 8ri5/Ffh5DG1CsN/dkv8n1kw2QqMM2RT+ZS57D+yCehtw355EXSVh2r+GsXAqMinOexcdYI4 skvvP84OovRMnlJhmRdnbjO+QFiOVeLUj7WHMT3AbClaBlUuHkbFi9HLBHAiu6uMrNtzAQD9 KoM6SXbuvlhCq2v78dGkex9EgaA7CSnBcNXuUdrjYQf+MsZgI7oDihT6TUBO0IDQL+qSrozs /hHV+HhWtc5+SYTsHXxnTkcVe12vR0uPw3fFUuncWnMRzHivKZC2ZF/w3LJL/nGzguAoPa9e VghM38EP49yO6ESthD4WvELMy2+zPkMiUqilMfxOl370RXxEBUIzFSpP6oqvNq7fvThGTQah mrFhflGSyMHXk75VkCiY+cbrMeB9xG7H3nlbQ9fYVCOPejnt8gImeazdIghQh1tjbNpjQhy8 50klCowN5H+gaSZsy4K7jlJ1UNFz/vWCvlr3W8o4tA6EoJ4tjJV2HXcrUBPYLwkruKnv8QJM vyVj5an6Sfuwt/AmFEOKo1QJnAf+Oi47RrOmec8lXS/06TMn7z6krmuRul03HXayCtREqMyY VCf87oMpPYYnFJolDrSB8kCSZRn2aixzHl4IIGa9RVuywChzUvgZJbFGPFR+Qz1BK9Ltl7FC rQcuAqg3A2RJ7uoTNiZDfI0tKWm8BEUe5LqZqgFTkTkuV9D6UveYnDk2zUFGlDTguagW2XWI wiGaA9Ud7UBBlQGTZUwNGahAErUHI5gDSNfWEUaRBEccWKgddK3a/NhkxOveqDWWFcAt4K/g JOqBs+7Bm0RjQa+4EAP6gFx4098XBZP9ff6pPuFWRN6fvfdBDUMHqb3i2SGDWVPrRR/x+Iz/ yfjdWlC/87QoRGVuaXMgT2JyZXprb3YgPGRlbmlzb2JyZXprb3ZAZ21haWwuY29tPoiWBBMR CAA+FiEExuZY9Y+VSLigQ/5M+4kLEySe7PkFAlrAxPQCGyMFCQWjmoAFCwkIBwIGFQgJCgsC BBYCAwECHgECF4AACgkQ+4kLEySe7PleSQEAktULi71pVGKh0vykq0wrn6IyqXx1SLFNwLcr PnZ2N5gA/3Ipzf3vXWXWCwRR07BB/H+9XgqWRl3jsu5EL9TzmyFAuQINBFrAxPQQCADaIOKd +PPUX4GvjdLikKxHsFRRpk75LiFZJcFU8cCA0M4Dg/Q0LcSX82TfgrfU34y7/rrF4ig/Dj81 H8MB2u01lYA2QpQ/XdHfwFMxkj5FCB4Cq6EqGxsXsaRhw4Qu3ouiJiHCEeoMoloBLOlqpXBf qnJSnBXYJDnlyvxoFIVpX4l+q2xJk/877otbPK5TBYdeHQv/f7cWNxIUT5Feth9DVq4B9OG1 BgOA1gH13KUmWhMaO+k/rYCJd9UiRoGm7FihyWrsRnG5K6VNnLjwjMjxDukNxdlITVbeK5/E QaiKRGRcTp3OwfHy6HlQH/JXGGyfmEx0rKVjoW/DD76MPpk/AAMFB/0SBNOW9asG5HeRKhJm QOPJDwNQik4t8uuZb7mw6+QoQuyzMBkXvhL7Aud0OluPeSYL2jZPw2IB26gvlUVva+FJRW9X 7cInI5mnuB4HBGdNpzR+ngRzFyf+qsd6cUrrioQUQozQKCgKG/J2LimV1fC4hQW0n5Q0qM9I KX3PtRCgxItQbn/HdqkTXqv8oxDB9cQILJvIYDZnVLojB4rJFUNb397ao3qaXdXj3iaX6wwJ 2Oo3cSxMGdY/8grRTDGYjItpWEM2noIRzdWSybzavtLHu/LmG4rbgy2aNm/TiVp28G5KvWW/ fCLomZhN0JscRgSkYjSaxmMgEdks1h9DWTHkiH4EGBEIACYWIQTG5lj1j5VIuKBD/kz7iQsT JJ7s+QUCWsDE9AIbDAUJBaOagAAKCRD7iQsTJJ7s+UF2AQDqHEO2tekVMTWJa3SakIM5FJjk sao+JkzbKe0vDy4ecwEAukGaHvmKxMZsUOOjDWjDe4eV+aRTVjUjY7LAl3OJkiU=
- Cc: "xen-devel@xxxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxxx>, nd <nd@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Hunyue Yau <hy-gsoc@xxxxxxxxxxxxxxx>
- Delivery-date: Sat, 06 Jul 2019 16:50:36 +0000
- List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
- Openpgp: preference=signencrypt
>> Ok, I changed it and was able to boot to the previous error. I think a
>> logical next step would be to set up the uart somehow?
>
> Do you mean the UART used by Xen?
Yes, to be able to switch between xen and dom0, to download a produced
dt for dom0 for example.
>
>>>
>>> But this feels weird to map then unmap the mmio. Instead, you should
>>> blacklist the crossbar device. Have a look at the field blacklist_dev in
>>> platform_desc.
>> Hm, I can see that in the device tree the crossbar has a phandle
>> property <0x00000008> and the main node has an interrupt-parent property
>> 0x00000008. So, all the interrupts seems to be mapped to the crossbar.
>> Wouldn't be that a problem if we blacklist the device?
>
>
> The Device is owned by Xen, so technically Dom0 does not see the
> hardware one. Instead it sees a virtual and therefore the node should be
> created to reflect it.
>
> The purpose of recreating the node is you can alter it to match what we
> actually exposed to the domain (property values may differ). It may
> happen that a lot of information are exactly the same as the hardware
> and can just be copied.
>
> This is, for instance, what we do for the GIC and timer.
I mean if we expose only GIC to the dom0 then we need to change the
interrupt-parent property to make all nodes have GIC's phandle as their
interrupt-parent. And when dom0 tries to modify irq connections then xen
should modify the crossbar. It seems to be a bit error prone approach.
>
>> Also, the tegra
>> implementation blacklist only a uart.
>
> I don't understand this.
In here [1] you can find that only uart is blacklisted (in
tegra_blacklist_dev[]). So, in tegra they didn't blacklist their version
of the crossbar.
[1]
https://lists.xenproject.org/archives/html/xen-devel/2017-04/msg00993.html
--
Regards, Denis Obrezkov
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