On Tuesday, October 16, 2018, 3:30:24 PM CEST [email protected] wrote: > Hi Jonas, > > On 07.10.2018 15:57, Jonas Danielsson wrote: > > From: Jonas Danielsson <[email protected]> > > > > This fixes a bug where our embedded system (AT91SAM9260 based) would > > hang at reboot. At the most we managed 16 boot loops without a hang. > > > > With this patch applied the problem has not been observed and the board > > has managed above 250 boot loops. > > > > The AT91SAM9260 datasheet tells us that with the instruction cache > > disabled all instructions are fetched from SDRAM. And we have an errata > > telling us we must power down the SDRAM before issuing cpu reset. > > > > This means we need the instruction cache enabled in at91sam9260_reset() > > At the moment it is being disabled in cpu_proc_fin() which is called from > > arch/arm/kernel/reboot.c. > > Are you using kexec reboot or implemented hibernate mode on this machine? > I'm seeing cpu_proc_fin() is called only in case of kexec reboot or > switching to hibernate mode. > > In case of normal reboot (e.g. reboot command) machine_restart() from > arch/arm/kernel/reboot.c is called. Please correct me if I'm wrong.
Another location is cpu_reset() aka cpu_arm926_reset() in proc-arm926.S which also disables I-cache. But I can't track down a callstack ending there. Best regards, Alexander
