[U-Boot] [PPC] get_timer without CONFIG_INTERRUPTS

[U-Boot] [PPC] get_timer without CONFIG_INTERRUPTS

[Chris Packham]

Hi,

Has anyone looked at a way of implementing get_timer for PowerPC without
using interrupts.

We appear to be having a problem with common/usb_hub.c where
occasionally (1 in ~150 reboots) we seem to get stuck in the do/while
loop in usb_hub_configure. It looks like this should timeout but because
we don't define CONFIG_INTERRUPTS get_timer() will only ever return 0.

I'm being a little paranoid (perhaps too paranoid) about turning on
CONFIG_INTERRUPTS. Looking at the code I can't see too much that would
cause problems but I want to avoid a rogue LBC or PCI-e interrupt
locking up the CPU.

Thanks,
Chris

[U-Boot] [PPC] get_timer without CONFIG_INTERRUPTS

[Chris Packham]

On 30/09/13 21:22, Chris Packham wrote:
> Hi,
> 
> Has anyone looked at a way of implementing get_timer for PowerPC without
> using interrupts.
> 
> We appear to be having a problem with common/usb_hub.c where
> occasionally (1 in ~150 reboots) we seem to get stuck in the do/while
> loop in usb_hub_configure. It looks like this should timeout but because
> we don't define CONFIG_INTERRUPTS get_timer() will only ever return 0.
> 
> I'm being a little paranoid (perhaps too paranoid) about turning on
> CONFIG_INTERRUPTS. Looking at the code I can't see too much that would
> cause problems but I want to avoid a rogue LBC or PCI-e interrupt
> locking up the CPU.
> 
> Thanks,
> Chris
> 

To answer my own question you do not need CONFIG_INTERRUPTS for
get_timer to work. You do however have to have called interrupts_init.
Our mistake was to add a call to usb_start in our boards misc_init_r.

[U-Boot] [PPC] get_timer without CONFIG_INTERRUPTS

[Wolfgang Denk]

Dear Chris,

In message <524BCCEE.5020907@gmail.com> you wrote:
>
> Our mistake was to add a call to usb_start in our boards misc_init_r.

You never want to run this automatically.  And if you do, you
absolutely must make sure to shut down the USB controller after use /
before booting Linux, otherwise you will experience rare and almost
impossible to debug memory corruption errors in Linux.

Best regards,

Wolfgang Denk

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