src/sim/PowerState.py

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from m5.SimObject import SimObject
from m5.params import *
from m5.proxy import *

# Enumerate set of allowed power states that can be used by a clocked object.
# The list is kept generic to express a base minimal set.
# State definition :-
#   Undefined: Invalid state, no power state derived information is available.
#   On: The logic block is actively running and consuming dynamic and leakage
#       energy depending on the amount of processing required.
#   Clk_gated: The clock circuity within the block is gated to save dynamic
#              energy, the power supply to the block is still on and leakage
#              energy is being consumed by the block.
#   Sram_retention: The SRAMs within the logic blocks are pulled into retention
#                   state to reduce leakage energy further.
#   Off: The logic block is power gated and is not consuming any energy.
class PwrState(Enum): vals = [
        'UNDEFINED', 'ON', 'CLK_GATED', 'SRAM_RETENTION', 'OFF'
]

class PowerState(SimObject):
    type = 'PowerState'
    cxx_header = "sim/power_state.hh"
    cxx_class = 'gem5::PowerState'

    # Provide initial power state, should ideally get redefined in startup
    # routine
    default_state = Param.PwrState("UNDEFINED", "Default Power State")

    # Possible power states this object can be in sorted from the most
    # to the least performant
    possible_states = VectorParam.PwrState(
        [], "Power states this object can be in")

    clk_gate_min = Param.Latency('1ns',"Min value of the distribution")
    clk_gate_max = Param.Latency('1s',"Max value of the distribution")
    clk_gate_bins = Param.Unsigned('20', "# bins in clk gated distribution")

    # The objects which drive the power state of this object. If the list is
    # empty, the object determines its power state independently.
    leaders = VectorParam.PowerState(
        [], "Objects which drive the power state of this object")