On Thu, Jul 30, 2026 at 05:37:52PM +0200, Quentin Schulz wrote: > Hi Johan, > > On 7/24/26 11:53 AM, Johan Jonker wrote: > > > > > > On 7/24/26 10:45, Quentin Schulz wrote: > > > Hi Johan, > > > > > > On 7/24/26 12:17 AM, Johan Jonker wrote: > > > > Not all Rockchip SoC models use the ARM arch timer. > > > > Call the function timer_init() only when > > > > CONFIG_SYS_ARCH_TIMER is available. > > > > Replace the ifdef call condition by IS_ENABLED > > > > to increase build coverage and make the code easier to read. > > > > > > > > Signed-off-by: Johan Jonker <[email protected]> > > > > Reviewed-by: Simon Glass <[email protected]> > > > > --- > > > > > > > > Previous version not needed for serie, so resend separate. > > > > https://patchwork.ozlabs.org/project/uboot/patch/[email protected]/ > > > > > > > > > > > Hi Quentin, > > > You didn't answer Kever's question in the linked patch and I have the > > > same question. > > > > Yes we end up the same code. But... > > > > > > > > This is essentially the same code, so what's the benefit, are you trying > > > to fix a specific issue? How does this improve the situation? > > > How does doing that increase code coverage... etc :) > > > > This patch originates around the time this concept as introduced. > > We are changing all code to the new norm and we leave this as it is... > > Fix this as well as a favor to Simon as part of the review. As we are there > > then fix them all as this is the new norm. > > https://patchwork.ozlabs.org/project/uboot/patch/[email protected]/ > > > > This doesn't point at what Simon could have said that prompted this patch. > The pointed patch did actually fix something, and instead of using > > #ifdef CONFIG_SYS_ARCH_TIMER > > you used > > if (IS_ENABLED(CONFIG_SYS_ARCH_TIMER)) > > which is absolutely the correct and "modern" way of doing it.
Right, and when it makes sense to and improves the readability of the
overall code. If it not a must-do every time. There is a judgement call
to it.
> > The concept:
> >
> > Currently with #ifdef the compiler sees this code:
> > =============
> >
> > rockchip_stimer_init();
> >
> > ret = dram_init();
> >
> > =============
> >
> > Now the compiler sees this code:
> >
> >
> > int timer_init(void)
> > {
> > gd->arch.tbl = 0;
> > gd->arch.tbu = 0;
> >
> > #ifdef CFG_SYS_HZ_CLOCK
> > gd->arch.timer_rate_hz = CFG_SYS_HZ_CLOCK;
> > #else
> > gd->arch.timer_rate_hz = read_cntfrq();
> > #endif
> > return 0;
> > }
> >
> >
> >
> > rockchip_stimer_init();
> >
> > if (IS_ENABLED(CONFIG_SYS_ARCH_TIMER))
> > timer_init();
> >
> > ret = dram_init();
> >
> > ============
> >
> > By using IS_ENABLED and CONFIG_IS_ENABLED the compiler is able to look
> > further into code and catch possible errors or warnings.
>
> I don't know anything about compilers but I'm surprised this would actually
> do anything different than what we currently have.
>
> If CONFIG_SYS_ARCH_TIMER is not set, then you get
>
> if (0)
> timer_init();
>
> which the compiler will (hopefully) see as a non-reachable branch and
> discard it.
>
> Otherwise, it'll be:
>
> if (1)
> timer_init();
>
> which hopefully the compiler will simply replace without the branch:
>
> timer_init();
>
> Maybe Simon or someone else can teach me something here because my naive
> view on this is: does not make a difference. What kind of benefits do we
> have, what do you run to see those benefits?
The compiler benefit that using IS_ENABLED provides is that we will make
sure that timer_init is declared in a header that is included. That's
it. It can be useful for more generic code, but it's of course imperfect
if the include chain brings it on some platforms, but not others (as a
warning pointed out on IRC today reminded me).
> > There is even a warning for it in ./scripts/checkpatch.pl
> >
>
> I'm aware, I quite often trigger it :)
>
> > ============
> > __weak void rockchip_stimer_init(void)
> > {
> > #if defined(CONFIG_ROCKCHIP_STIMER_BASE)
> >
> > #endif
> > }
> > ============
> > There are exceptions like in rockchip_stimer_init where certain defines are
> > missing, so that's still allowed.
> > In all other settings we use IS_ENABLED and CONFIG_IS_ENABLED.
> > Hope that explains your questions.
> >
>
> Not really no, sorry.
>
> The commit log is misleading and needs rewording. As far as my understanding
> goes, it's clean-up. Maybe there's something helpful for the compiler but
> you need to prove it because I don't see it (I'm interested to know if it
> does, so please tell us!).
I agree, at minimum, the commit message isn't clear that we're just
replacing #ifdef with if (IS_ENABLED()) as a clean-up. I'll defer to
Quentin on if that's worthwhile doing here, or not.
--
Tom
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