Matthias Fuchs wrote:
Hi,
after going through the boom code I found out, that setting the 'autostart' variable to 'no' brings me a little closer to what I want. But finally I end up in the enable_interrupts() at the very end of do_bootm(). This freezes my system. The reason for this is the Linux kernel image that is loaded to address 0 and that overwrites the vector table. So reenabling the interrupts in U-Boot with Linux interrupt table is a bad idea.
No, having your (u-boot) interrupt go off while booting linux is a bad idea.
Which interrupt is going off? Why is it going off (why isn't the hardware put into a quiescent state)?
So what's the best idea to fix this? I could copy the vector table onto the stack in do_bootm() and copy it back just before reenabling the interrupts.
NO NO NO.
Any better idea?
Matthias
That a u-boot initialized interrupt is occurring is wrong and needs to be fixed. * Traditionally, u-boot does not use interrupts for anything, thus this isn't a problem.
* Proper hardware and device driver convention is that the hardware must be quiescent when linux is started and the linux device driver must (re)configure that hardware the way it wants/needs. Obviously, this is probably a 95% rule (console I/O, memory initialization, some others may violate this rule for practical reasons).
* If your u-boot enables interrupt(s), you MUST disable the interrupt source before starting linux. There is NO graceful way of getting linux to handle an interrupt that was a result of u-boot's running. Starting linux with interrupts disabled is not a good solution - you may get lucky but leaving an active interrupt source is a dangerous game. At best, it is a race condition that you may happen to win today.
Best regards, gvb