Mark Rutland <mark.rutland@xxxxxxx> writes: > On Fri, Mar 04, 2016 at 10:55:03AM -0800, Eric Anholt wrote: >> Mark Rutland <mark.rutland@xxxxxxx> writes: >> >> > On Fri, Mar 04, 2016 at 10:39:29AM -0800, Eric Anholt wrote: >> >> For now this doesn't support the new hardware present on the Pi 3 (BT, >> >> wifi, GPIO expander). Since the GPIO expander isn't supported, we >> >> also don't have the LEDs like the other board files do. >> >> >> >> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx> >> >> --- >> >> arch/arm/boot/dts/Makefile | 3 +- >> >> arch/arm/boot/dts/bcm2837-rpi-3-b.dts | 22 ++++++++++++ >> >> arch/arm/boot/dts/bcm2837.dtsi | 68 +++++++++++++++++++++++++++++++++++ >> >> 3 files changed, 92 insertions(+), 1 deletion(-) >> >> create mode 100644 arch/arm/boot/dts/bcm2837-rpi-3-b.dts >> >> create mode 100644 arch/arm/boot/dts/bcm2837.dtsi >> > >> >> + timer { >> >> + compatible = "arm,armv7-timer"; >> >> + interrupt-parent = <&local_intc>; >> >> + interrupts = <0>, // PHYS_SECURE_PPI >> >> + <1>, // PHYS_NONSECURE_PPI >> >> + <3>, // VIRT_PPI >> >> + <2>; // HYP_PPI >> >> + always-on; >> >> + }; >> > >> > Are the CPUs in an always-on power domain? Or is it jsut that the kernel >> > doesn't perform power management of CPUs? >> > >> > The always-on proeprty is only intended for the former. >> >> The kernel doesn't get to do power management of CPUs. We only have >> control of power domains through the firmware, and the firmware's >> keeping the CPU domain on. > > So there is no way that the CPUs could request for the firmare to place > them in a state where the timer would lose context (but other events > coukd wake them up), even if they don't do that today? I don't see any mechanism in the RPi firmware for the ARM to request suspend or anything like that. Enabling something like that would definitely require an updated DT, to enable a driver that talks to the firmware to make requests like that. (Note that this is the same timer setup we have in bcm2836.dtsi)
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