On 22/03/2021 17:33, Tony Lindgren wrote: > Hi, > > * Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> [210322 15:56]: >> On 04/03/2021 08:37, Tony Lindgren wrote: >>> There is a timer wrap issue on dra7 for the ARM architected timer. >>> In a typical clock configuration the timer fails to wrap after 388 days. >>> >>> To work around the issue, we need to use timer-ti-dm timers instead. >>> >>> Let's prepare for adding support for percpu timers by adding a common >>> dmtimer_clkevt_init_common() and call it from dmtimer_clockevent_init(). >>> This patch makes no intentional functional changes. >>> >>> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx> >>> --- >> >> [ ... ] >> >>> @@ -575,33 +574,60 @@ static int __init dmtimer_clockevent_init(struct device_node *np) >>> */ >>> writel_relaxed(OMAP_TIMER_CTRL_POSTED, t->base + t->ifctrl); >>> >>> + if (dev->cpumask == cpu_possible_mask) >>> + irqflags = IRQF_TIMER; >>> + else >>> + irqflags = IRQF_TIMER | IRQF_NOBALANCING; >> >> Can you explain the reasoning behind the test above ? > > In the per cpu case we assign one dmtimer per cpu, and we want the > interrupt handling on the assigned CPU. In the per cpu case we have > the cpu specified with dev->cpumask unlike for the normal clockevent > case. > > In the per cpu dmtimer case the interrupt line is not wired per cpu > though, so I don't think we want to add IRQF_PERCPU here. If it is per cpu, then the parameter will be cpumask_of(cpu). If there is one cpu, no balancing can happen and then the IRQF_NOBALANCING is not needed, neither this test and the irqflags, right? -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
