On Wed, May 08, 2013 at 04:38:22PM +0200, Arnd Bergmann wrote: > On Wednesday 08 May 2013, Srinivas KANDAGATLA wrote: > > From: Stuart Menefy <stuart.menefy@xxxxxx> > > > > This is a simple driver for the global timer module found in the Cortex > > A9-MP cores from revision r1p0 onwards. This should be able to perform > > the functions of the system timer and the local timer in an SMP system. > > > > The global timer has the following features: > > The global timer is a 64-bit incrementing counter with an > > auto-incrementing feature. It continues incrementing after sending > > interrupts. The global timer is memory mapped in the private memory > > region. > > The global timer is accessible to all Cortex-A9 processors in the > > cluster. Each Cortex-A9 processor has a private 64-bit comparator that > > is used to assert a private interrupt when the global timer has reached > > the comparator value. All the Cortex-A9 processors in a design use the > > banked ID, ID27, for this interrupt. ID27 is sent to the Interrupt > > Controller as a Private Peripheral Interrupt. The global timer is > > clocked by PERIPHCLK. > > > > Signed-off-by: Stuart Menefy <stuart.menefy@xxxxxx> > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxx> > > > > Are you sure we don't already have a driver for this? It sounds unlikely > that you are the first one to do this when the hardware is so common. > Isn't this the same as arch/arm/kernel/smp_twd.c ? That is atleast the timer I used with Cortex-A9. I don't think the core has another one. But maybe I'm wrong. > > Documentation/devicetree/bindings/arm/gt.txt | 21 ++ > > arch/arm/Kconfig | 6 + > > arch/arm/include/asm/global_timer.h | 12 + > > arch/arm/kernel/Makefile | 1 + > > arch/arm/kernel/global_timer.c | 325 ++++++++++++++++++++++++++ > > 5 files changed, 365 insertions(+), 0 deletions(-) > > create mode 100644 Documentation/devicetree/bindings/arm/gt.txt > > create mode 100644 arch/arm/include/asm/global_timer.h > > create mode 100644 arch/arm/kernel/global_timer.c > > Move it into drivers/clocksource? > > > diff --git a/arch/arm/include/asm/global_timer.h b/arch/arm/include/asm/global_timer.h > > new file mode 100644 > > index 0000000..46f9188 > > --- /dev/null > > +++ b/arch/arm/include/asm/global_timer.h > > @@ -0,0 +1,12 @@ > > +int __init global_timer_init(void __iomem *base, unsigned int timer_irq); > > I don't see a need to call this from platform code for non-DT platforms, it > can easily be used with CLOCKSOURCE_OF_DECLARE() all the time I think. > Regards, Steffen -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
