Adaptive wake-up for power conservation in a processor
A processor can include various processing pipelines that perform different data processing operations, with different pipelines having dedicated logic and memory circuits. A power management circuit can determine when to supply power to various pipelines, including the logic and memory circuits of the various pipelines, depending on a current operating mode of the processor. When a memory circuit transitions to a lower power state such as a sleep state, data can be saved to a different memory circuit that is not transitioning to a lower power state, and when the memory circuit is powered up again, the data can be restored from the different memory circuit.
1. A processor comprising:
a plurality of processing pipelines associated with different tasks, the plurality of processing pipelines including:
a first pipeline having first circuitry configured to process a wireless communication control channel;
a second pipeline having second circuitry configured to process a first wireless communication data channel; and
a third pipeline having third circuitry configured to process a second wireless communication data channel; and
a power management circuit configured to determine when to supply power to the first, second, and third circuitry wherein the power management circuit is configured to:
periodically power up the first circuitry to enable a listening operation to detect a data communication request via the wireless communication control channel;
power up the second and third circuitry when data communication is requested; and
transition the second and third circuitry to a lower power state in response to determining that data communication has ended.
2. The processor of claim 1 wherein the power management circuit is further configured such that the listening operation includes listening for a paging signal indicating that a base station has data to send to the processor.
3. The processor of claim 1 wherein the power management circuit is further configured to determine that data communication is requested based at least in part on an interrupt signal from a different processor indicating that the different processor has data ready to be transmitted.
4. The processor of claim 1 wherein the power management circuit is further configured such that determining that data communication has ended includes determining whether the processor has entered a connected discontinuous receive (CDRX) state or an idle state.
5. The processor of claim 1 wherein the plurality of processing pipelines includes a plurality of instances of the second pipeline having one or more instances of the second circuitry and wherein the power management circuit is further configured to:
determine a type of data communication requested; and
selectively power up one or more of the one or more instances of the second circuitry based at least in part on the type of data communication.
6. The processor of claim 1 wherein one or more of the second, or third circuitry includes a respective volatile memory circuit and wherein the power management circuit is further configured such that transitioning one or more of the second or third circuitry to the lower power state includes saving data from the respective volatile memory circuit to a different memory circuit that is not transitioning to the lower power state.
7. The processor of claim 6 wherein the power management circuit is further configured such that powering up one or more of the second or third circuitry includes restoring data from the different memory circuit to the respective volatile memory circuit.
8. An electronic device comprising:
a first processor; and
a second processor coupled to the first processor,
wherein the second processor includes:
a plurality of processing pipelines associated with different tasks, the plurality of processing pipelines including:
a first pipeline having first circuitry configured to process a physical downlink control channel;
a second pipeline having second circuitry configured to process a physical downlink shared channel; and
a third pipeline having third circuitry configured to process one or more physical uplink channels; and
a power management circuit configured to manage one or more power states, including:
a sleep state in which the first, second, and third circuitry are in a low power state;
a listening state in which the first circuitry is powered up while the second and third circuitry is in the low power state; and
a data communication state in which the first, second, and third circuitry are powered up,
wherein the power management circuit is further configured to:
periodically transition from the sleep state to the listening state;
while in the listening state, determine whether data communication should be enabled and transition from the listening state to the data communication state in response to determining that data communication should be enabled; and
while in the data communication state, determine whether data communication has ended and transition from the data communication state to the sleep state in response to determining that data communication has ended.
9. The electronic device of claim 8 wherein the power management circuit is further configured to:
receive an interrupt signal from the first processor while in either the sleep state or the listening state, the interrupt signal indicating that the electronic device has data ready to be sent; and
transition to the data communication state in response to receiving the interrupt signal.
10. The electronic device of claim 8 wherein the plurality of processing pipelines includes a plurality of instances of the second pipeline and wherein the one or more power states include a plurality of data communication states including:
a first data communication state in which all instances of the second pipeline are powered up; and
a second data communication state in which at least one and fewer than all instances of the second pipeline are powered up,
wherein the power management circuit is further configured to select one of the plurality of data communication states based on a type of data communication that should be enabled.
11. The electronic device of claim 10 wherein the second processor comprises a cellular modem processor configured to support data communication using a 4G radio area network and data communication using a 5G radio area network, and wherein the power management circuit is further configured to select the first data communication state for data communication using the 5G radio area network and to select the second data communication state for data communication using the 4G radio area network.
12. The electronic device of claim 8 wherein one or more of the first, second, or third circuitry includes a volatile memory circuit and wherein the power management circuit is further configured such that transitioning to the sleep state includes saving data from the volatile memory circuit to a different memory circuit that is not being powered down.
13. The electronic device of claim 12 wherein the power management circuit is further configured such that powering up one or more of the first, second, or third circuitry includes restoring data from the different memory circuit to the volatile memory circuit.
14. A method implemented in a processor, the method comprising:
placing the processor into a sleep state in which a plurality of processing pipelines are in a low power state, wherein the plurality of processing pipelines includes a first pipeline having first circuitry configured to process a physical downlink control channel, a second pipeline having second circuitry configured to process a physical downlink shared channel, and a third pipeline having third circuitry configured to process one or more physical uplink channels;
determining when a paging interval has elapsed;
in response to determining that the paging interval has elapsed:
entering a listening state, wherein entering the listening state includes powering up the first pipeline including the first circuitry; and
determining, based at least in part on downlink control information received using the first pipeline, whether a base station has data ready to send to the processor;
in response to determining that the base station has data ready to send, entering a data communication state, wherein entering the data communication state includes powering up the second and third circuitry;
determining that the data communication state should be exited; and
in response to determining that the data communication state should be exited, returning to the sleep state, wherein returning to the sleep state includes powering down the first, second, and third circuitry.
15. The method of claim 14 further comprising:
in response to determining that the data communication state should be ended, powering down the first circuitry.
16. The method of claim 14 wherein at least one of the second or third circuitry includes a volatile memory circuit and disabling power to the second and third circuitry includes saving data from the volatile memory circuit to a different memory circuit.
17. The method of claim 16 wherein enabling power to at least one of the second or third circuitry includes restoring data from the different memory circuit to the volatile memory circuit.
18. The method of claim 14 further comprising:
while in the sleep state, receiving an interrupt signal from another processor indicating that the other processor has data ready to transmit; and
in response to the interrupt signal, entering the data communication state, wherein entering the data communication state further includes enabling power to the first circuitry.
19. The method of claim 18 wherein the other processor is an application processor of an electronic device.
20. The method of claim 14 further comprising:
while in the listening state, receiving an interrupt signal from another processor indicating that the other processor has data ready to transmit; and
in response to the interrupt signal, entering the data communication state regardless of whether the base station has data ready to send.