• Lina Iyer's avatar
    ARM: qcom: Add Subsystem Power Manager (SPM) driver · 7ce75bb2
    Lina Iyer authored
    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@codeaurora.org>,
    Ai Li <ali@codeaurora.org>, Praveen Chidambaram <pchidamb@codeaurora.org>
    Original tree available at -
    git://codeaurora.org/quic/la/kernel/msm-3.10.git
    
    Cc: Stephen Boyd <sboyd@codeaurora.org>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Kevin Hilman <khilman@linaro.org>
    Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
    Signed-off-by: default avatarLina Iyer <lina.iyer@linaro.org>
    Reviewed-by: default avatarStephen Boyd <sboyd@codeaurora.org>
    Tested-by: default avatarKevin Hilman <khilman@linaro.org>
    Acked-by: default avatarKumar Gala <galak@codeaurora.org>
    Acked-by: default avatarKevin Hilman <khilman@linaro.org>
    Signed-off-by: default avatarKumar Gala <galak@codeaurora.org>
    7ce75bb2
Makefile 70 Bytes