Hi On Mon, 10 Sep 2012, Jon Hunter wrote: > From: Ming Lei <ming.lei@xxxxxxxxxxxxx> > > For OMAP4430 there are no dedicate PMU interrupts, however, PMU events can be > routed to via the CTI IRQs. This allows tools such as PERF and OPROFILE to work > on OMAP4430. > > The idea is from Woodruff Richard in the disscussion about "Oprofile on > Pandaboard / Omap4" on pandaboard@xxxxxxxxxxxxxxxx. > > Ming's original patch was called "arm: omap4: support pmu" [1] and has been > renamed and modified by Jon Hunter. There main differences from the original > patch are ... > > 1. Instead of only configuring the CTI interrupt once during boot, the > interrupts are configured everytime the the PMU is used. The reason for this > is because during power transitions the CTI logic state will be lost and so > we will need to configure the interrupts everytime they are used. This is > accomplished by using the PM runtime callbacks which will be called whenever > the PMU is used. > 2. Assign the PMU events to different cross triggering channels. This prevents > a single PMU event generating interrupts to both CPUs and hence can cause > spurious interrupts to occur. Reported by Ming [2]. > > [1] http://marc.info/?l=linux-arm-kernel&m=132227620816504&w=2 > [2] http://permalink.gmane.org/gmane.linux.linaro.devel/10532 Spent some time with this one here. At this point I don't think I can queue it. It's got hardcoded IRQ numbers and address information for the CTI, and mixes the CTI and PMU programming. A few months ago we might have gotten away with this, but now it seems best to do this one cleanly. Probably the CTI control should be moved off into mach-omap2/omap4-cti.c or somewhere into drivers/ if possible. So let's revisit this for 3.8. - Paul -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
