<ad__>
hi, on h3 (armv7), what is the reason u-boot switches to non-secure to start secure monitor ? Trying to understand how the whole things works. Do the cpu starts in secure mode ?
<valdikss>
pnill: thanks for a very useful link. This thing should generate modeline for completeness.
<pnill>
valdikss: I don't think I would've been successful in configuring the display I was playing with if it wasn't for it because otherwise it was too much trial and error lol
<pnill>
The original timing/lcd configuration going through the LVDS transmitter
<pnill>
was causing the screen to flicker and do other weird crap.
<pnill>
The link you sent is interesting but doesn't seem nearly as user-friendly, the link I'd given seemed to give everything I needed for the fex/dtb
<pnill>
What is the different between CVT/CVT-RB btw?
<pnill>
*difference
<valdikss>
timings!
<valdikss>
the lower the pixel clock, the better, but not all hardware is capable of working on newer standards
apritzel has quit [Ping timeout: 480 seconds]
ftg has joined #linux-sunxi
apritzel has joined #linux-sunxi
cnxsoft1 has joined #linux-sunxi
prefixcactus has joined #linux-sunxi
cnxsoft has quit [Ping timeout: 480 seconds]
<apritzel>
ad__: ARM cores always start in secure state (otherwise you would never be able to get there)
<apritzel>
ad__: so at least the BROM runs in secure SVC, and so does the SPL (or boot0)
<ad__>
apritzel, thanks a lot. So, seems that u-boot, to setup secure monitor, moves to non-secure state. Why is it needed ?
<apritzel>
ad__: in U-Boot proper we switch to non-secure (HYP, actually), as we install the PSCI handlers in (always secure) monitor mode
<ad__>
apritzel, aha thanks. Just wondering if that may be done in secure mode
<apritzel>
technically 32-bit ARM Linux can run in secure state (in contrast to arm64, which forbids this), and actually many (older) platforms do, but it's better to run it non-secure
<apritzel>
ad__: please keep in mind that there is no secure *mode*, it's a secure *state*
<apritzel>
these whole state/mode/exception levels are admittedly somewhat messy in ARMv7, one of the many blessings of ARMv8, which cleaned that up nicely
warpme___ has joined #linux-sunxi
<ad__>
apritzel, aha ok, thanks really, such concepts in brief seems hard to find. So switchng to non-secure is a step done just before running linux, not mandatory to install psci handlers, correct ?
<apritzel>
ad__: we could install the PSCI handlers in monitor mode, then continue booting Linux in secure SVC
<apritzel>
ad__: BUT the virtualisation extension works only in HYP mode, which is always non-secure
<apritzel>
so to be able to use KVM (RIP!), we need to enter Linux in (non-secure) HYP mode
<apritzel>
ad__: and to answer your question: installing PSCI handlers *requires* secure state, otherwise you wouldn't be able to set the MVBAR register
<apritzel>
and you need MVBAR, because this is where SMC calls trap to
<apritzel>
ad__: as I said: use ARMv8 AArch64, it's so much cleaner ;-)
<ad__>
apritzel, thanks a lot really, will study on all this
<apritzel>
ad__: yeah, sorry, it's confusing, and I am not super versed in ARMv7
<ad__>
you seems really expert :) ok thanks, will combine yours info above with arm documents :)
<apritzel>
ad__: good luck with that, feel free to come back here ;-)
<ad__>
apritzel, thanks !
<apritzel>
(the ARM ARM is not easy reading, so take a deep breath)
gsz has joined #linux-sunxi
cnxsoft1 has quit [Remote host closed the connection]
cnxsoft has joined #linux-sunxi
Mangy_Dog has joined #linux-sunxi
<apritzel>
does anyone know about the differences between the A133 and the A100?
Danct12 has quit [Quit: Quitting]
Danct12 has joined #linux-sunxi
cnxsoft has quit [Ping timeout: 480 seconds]
sunshavi has quit [Ping timeout: 480 seconds]
JohnDoe_71Rus has joined #linux-sunxi
apritzel_ has joined #linux-sunxi
apritzel_ has quit [Ping timeout: 480 seconds]
macromorgan has quit [Quit: Leaving]
tnovotny has quit [Quit: Leaving]
macromorgan has joined #linux-sunxi
Luke-Jr has quit [Ping timeout: 480 seconds]
Luke-Jr has joined #linux-sunxi
sunshavi has joined #linux-sunxi
apritzel has quit [Ping timeout: 480 seconds]
gsz has quit [Quit: leaving]
apritzel_ has joined #linux-sunxi
JohnDoe_71Rus has quit []
hlauer has joined #linux-sunxi
apritzel_ has left #linux-sunxi [#linux-sunxi]
apritzel has joined #linux-sunxi
paulk3 has joined #linux-sunxi
paulk2 has quit [Ping timeout: 480 seconds]
Daanct12 has joined #linux-sunxi
Danct12 has quit [Ping timeout: 480 seconds]
hlauer has quit [Ping timeout: 480 seconds]
paulk3 has quit [Ping timeout: 480 seconds]
megi3 has joined #linux-sunxi
megi2 has quit [Read error: Connection reset by peer]