Subject: [PATCH 2/2] ARM: Layerscape: Add LS1021A IOT board support

[Renaud Barbier]

> On Thu, Feb 23, 2023 at 01:58:46PM +0000, Renaud Barbier wrote:
> > diff --git a/arch/arm/lib32/pbl.c b/arch/arm/lib32/pbl.c new file mode
> > 100644 index 0000000000..f4be7b57dc
> > --- /dev/null
> > +++ b/arch/arm/lib32/pbl.c
> > @@ -0,0 +1,21 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +
> > +#include <asm/system.h>
> > +#include <clock.h>
> > +#include <common.h>
> > +
> > +void udelay(unsigned long us)
> > +{
> > +     unsigned long long ticks, cntfrq = get_cntfrq();
> > +     unsigned long long start = get_cntpct();
> > +
> > +     ticks = us * cntfrq + 999999;
> > +     do_div(ticks, 1000000);
> > +
> > +     while ((long)(start + ticks - get_cntpct()) > 0); }
> > +
> > +void mdelay(unsigned long ms)
> > +{
> > +     udelay(ms * 1000);
> > +}
> 
> This will be compiled for every arm32 build, but the architected timer is not
> generally available, only a small fraction of CPUs actually have it. I just tested
> this on a i.MX6 and it just answers with an illegal instruction abort when
> get_cntfrq() is called.
> 
> We could name this arm_architected_timer_udelay() or similar.
> 
> This change should be in a separate patch.
> 
And then you would add a udelay/mdelay wrapper at the board or machine level?