Re: [PATCH] bus: ti-sysc: Use fsleep() instead of usleep_range() in sysc_reset()

From: Tony Lindgren
Date: Wed Sep 13 2023 - 04:27:17 EST


* Tony Lindgren <tony@xxxxxxxxxxx> [230822 09:27]:
> * Julien Panis <jpanis@xxxxxxxxxxxx> [230821 14:24]:
> > The am335x-evm started producing boot errors because of subtle timing
> > changes:
> >
> > Unhandled fault: external abort on non-linefetch (0x1008) at 0xf03c1010
> > ...
> > sysc_reset from sysc_probe+0xf60/0x1514
> > sysc_probe from platform_probe+0x5c/0xbc
> > ...
> >
> > The fix consists in using the appropriate sleep function in sysc reset.
> > For flexible sleeping, fsleep is recommended. Here, sysc delay parameter
> > can take any value in [0 - 255] us range. As a result, fsleep() should
> > be used, calling udelay() for a sysc delay lower than 10 us.
> >
> > Signed-off-by: Julien Panis <jpanis@xxxxxxxxxxxx>
> > Fixes: e709ed70d122 ("bus: ti-sysc: Fix missing reset delay handling")
> > ---
> > Fix boot errors for am335x-evm in sysc_reset(), by using fsleep() instead
> > of usleep_range() function. Thus, udelay() will be called if the configured
> > sysc delay is lower than 10 us (which is usually the case, since the value
> > set in the device tree is currently 2 us).
>
> OK, interesting. Yeah I've only ever seen values of 2 us needed here.

Applied into fixes thanks

Tony