| Message ID | 20150211184515.GB11190@codeaurora.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
Stephen Boyd wrote: > Mason wrote: > >> Also, you wrote "I don't see any problem with the TWD dropping the >> dependency on SMP." Would something as simple as this be acceptable? >> (Most probably NOT; there are a lot of smp* occurrences in smp_twd.c >> even the file name.) What is the rationale for the dependency? >> >> >> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig >> index a34698d..47b02c8 100644 >> --- a/arch/arm/Kconfig >> +++ b/arch/arm/Kconfig >> @@ -1565,7 +1565,6 @@ config HAVE_ARM_ARCH_TIMER >> config HAVE_ARM_TWD >> bool >> - depends on SMP >> select CLKSRC_OF if OF >> help >> This options enables support for the ARM timer and watchdog unit >> > > Hmm it looks like we would also need to add this to the patch. It > looks like a holdover from when the local timer APIs were around. > Back then twd_local_timer_common_register() would fail if > is_smp() was false or setup_max_cpus was 0. Now it will just > register a clockevent that may or may not be used depending on > what other clockevents are in the system and the ratings of those > other clockevents. > > ----8<---- > diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c > index 172c6a05d27f..e8f6d241881f 100644 > --- a/arch/arm/kernel/smp_twd.c > +++ b/arch/arm/kernel/smp_twd.c > @@ -23,7 +23,6 @@ > #include <linux/of_irq.h> > #include <linux/of_address.h> > > -#include <asm/smp_plat.h> > #include <asm/smp_twd.h> > > /* set up by the platform code */ > @@ -388,9 +387,6 @@ static void __init twd_local_timer_of_register(struct device_node *np) > { > int err; > > - if (!is_smp() || !setup_max_cpus) > - return; > - > twd_ppi = irq_of_parse_and_map(np, 0); > if (!twd_ppi) { > err = -EINVAL; Looking at the difference between OF and !OF registration functions in smp_twd.c !OF if (twd_base || twd_evt) return -EBUSY; assign twd_ppi and twd_base twd_local_timer_common_register(NULL) OF if (!is_smp() || !setup_max_cpus) return; // TO BE DELETED assign twd_ppi and twd_base twd_local_timer_common_register(np) I suppose OF guarantees that the init code is called only once? (Hence the !OF guard code would be unnecessary.) Regards. -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 02/11, Mason wrote: > > Looking at the difference between OF and !OF registration functions > in smp_twd.c > > !OF > if (twd_base || twd_evt) return -EBUSY; > assign twd_ppi and twd_base > twd_local_timer_common_register(NULL) > > OF > if (!is_smp() || !setup_max_cpus) return; // TO BE DELETED > assign twd_ppi and twd_base > twd_local_timer_common_register(np) > > I suppose OF guarantees that the init code is called only once? It's called as many times as there's a match with the corresponding CLOCKSOURCE_OF_DECLARE. In practice that's once. > (Hence the !OF guard code would be unnecessary.) > The other difference is that OF based registration needs to use OF functions for irqs and ioremap whereas the non-OF code relies on the irqs being provided before hand and the ioremap done without OF functions.
diff --git a/arch/arm/kernel/smp_twd.c b/arch/arm/kernel/smp_twd.c index 172c6a05d27f..e8f6d241881f 100644 --- a/arch/arm/kernel/smp_twd.c +++ b/arch/arm/kernel/smp_twd.c @@ -23,7 +23,6 @@ #include <linux/of_irq.h> #include <linux/of_address.h> -#include <asm/smp_plat.h> #include <asm/smp_twd.h> /* set up by the platform code */ @@ -388,9 +387,6 @@ static void __init twd_local_timer_of_register(struct device_node *np) { int err; - if (!is_smp() || !setup_max_cpus) - return; - twd_ppi = irq_of_parse_and_map(np, 0); if (!twd_ppi) { err = -EINVAL;