[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [GSoC-2019] About the crossbar and xen


  • To: Hunyue Yau <hy-gsoc@xxxxxxxxxxxxxxx>
  • From: Denis Obrezkov <denisobrezkov@xxxxxxxxx>
  • Date: Thu, 11 Jul 2019 14:50:01 +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>, Julien Grall <julien.grall@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Iain Hunter <drhunter95@xxxxxxxxx>
  • Delivery-date: Thu, 11 Jul 2019 12:50:23 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xenproject.org>
  • Openpgp: preference=signencrypt

Hi,

>>
>> I am interested whether we should do something with omap5-wugen-mpu. I
>> found that crossbar is connected to GIC. And on some schemes in trm it
>> is connected via omap5-wugen-mpu. So, it is not clear for me whether it
>> should be handled in xen.
> 

Also, I am interested in how to add the crossbar. I can see two options
as we discussed earlier. The first option is to remove the crossbar but
for me it might cause some problems since a guest might want to use it.
The second option is to expose the crossbar and intercept all the calls
to it. But the problem is that now xen supports only one
interrupt-controller. And at the same time most of the SPI IRQs are
mapped to the crossbar. So, when xen checks whether the main
interrupt-controller is the same as the one to who external interrupts
are mapped it fails.
(xen/common/device_tree.c:dt_irq_translate()).
And I don't think that I should change interrupt-parent option of
devices to map them to the GIC because it is essentially the first
option mentioned above. So, it seems that probably interrupt-parent
finding decision logic should be changed a bit? Like to find a GIC node
not in a direct interrupt-parent but transitively in one of ancestors:

UART -> crossbar -> wugen -> GIC

What do you think?

-- 
Regards, Denis Obrezkov

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel

 


Rackspace

Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.