Lina Iyer <lina.iyer@xxxxxxxxxx> writes: > SPM is a hardware block that controls the peripheral logic surrounding > the application cores (cpu/l$). When the core executes WFI instruction, > the SPM takes over the putting the core in low power state as > configured. The wake up for the SPM is an interrupt at the GIC, which > then completes the rest of low power mode sequence and brings the core > out of low power mode. > > The SPM has a set of control registers that configure the SPMs > individually based on the type of the core and the runtime conditions. > SPM is a finite state machine block to which a sequence is provided and > it interprets the bytes and executes them in sequence. Each low power > mode that the core can enter into is provided to the SPM as a sequence. > > Configure the SPM to set the core (cpu or L2) into its low power mode, > the index of the first command in the sequence is set in the SPM_CTL > register. When the core executes ARM wfi instruction, it triggers the > SPM state machine to start executing from that index. The SPM state > machine waits until the interrupt occurs and starts executing the rest > of the sequence until it hits the end of the sequence. The end of the > sequence jumps the core out of its low power mode. > > Add support for an idle driver to set up the SPM to place the core in > Standby or Standalone power collapse mode when the core is idle. > > Based on work by: Mahesh Sivasubramanian <msivasub@xxxxxxxxxxxxxx>, > Ai Li <ali@xxxxxxxxxxxxxx>, Praveen Chidambaram <pchidamb@xxxxxxxxxxxxxx> > Original tree available at - > git://codeaurora.org/quic/la/kernel/msm-3.10.git > > Cc: Stephen Boyd <sboyd@xxxxxxxxxxxxxx> > Cc: Arnd Bergmann <arnd@xxxxxxxx> > Cc: Kevin Hilman <khilman@xxxxxxxxxx> > Cc: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> > Signed-off-by: Lina Iyer <lina.iyer@xxxxxxxxxx> Acked-by: Kevin Hilman <khilman@xxxxxxxxxx> and also tested on qcom-apq8064-ifc6410 and qcom-msm8974-sony-xperia-honami and saw the various states being entered on all CPUs. Tested-by: Kevin Hilman <khilman@xxxxxxxxxx> Kevin -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
