Configuration of a clock distribution system for an integrated circuit
A method for configuring a clock distribution system for an integrated circuit involves receiving an indication of frequencies of clock signal to supply to devices on the integrated circuit, selecting a configuration for the clock distribution system based on the frequencies required by the devices and an estimated power consumption, and providing an indication of the selected configuration for configuring the clock distribution system.
1. Method for configuring a clock distribution system for an integrated circuit, the method comprising the steps:
receiving a demand indication indicative of demanded clock frequencies for clock signals to be supplied to one or more devices of the integrated circuit;
selecting a selected configuration of the clock distribution system in accordance with the demand indication; and
providing a configuration indication for configuring the clock distribution system according to the selected configuration; in which
when a plurality of configurations of the clock distribution system are able to satisfy the demand indication, the selected configuration is selected from said plurality of configurations based on an estimated power consumption associated with said plurality of configurations.
2. Method according to claim 1 , wherein
the configuration indication indicates whether at least one clock system component of the clock distribution system is to be put into a power-saving state.
3. Method according to claim 1 , wherein
the configuration selected as the selected configuration from the plurality of configurations is the configuration with the lowest estimated power consumption.
4. Method according to claim 1 , wherein
for at least one of the plurality of configurations, the estimated power consumption is based on a number of clock signal generators indicated as being used according to the configuration.
5. Method according to claim 4 , wherein
the selected configuration selected from the plurality of configurations is a configuration that indicates the fewest clock signal generators as being in use; and
the configuration indication indicates that at least one clock signal generator unused in the selected configuration is to be put into a power-saving state.
6. Method according to claim 1 , wherein
for at least one of the plurality of configurations, the estimated power consumption is based on component power costs of clock system components of the clock distribution system indicated as being used according to the configuration.
7. Method according to claim 1 , wherein
the configuration indication indicates settings for clock system components of the clock distribution system, the clock system components comprising at least one clock signal generator and at least one clock distribution component.
8. Method according to claim 7 , wherein
the at least one clock distribution component comprises at least one of: a multiplexer, a demultiplexer, a phase-locked loop, a clock frequency multiplier, and a clock frequency divider.
9. Method according to claim 1 , wherein
when selecting between a first configuration which more closely satisfies the demand indication but is associated with a higher estimated power consumption and a second configuration which less closely satisfies the demand indication but is associated with a lower estimated power consumption, the selected configuration selected is the second configuration.
10. Method according to claim 1 , wherein
said plurality of configurations of the clock distribution system able to satisfy the demand indication comprise two or more configurations for which at least one frequency of clock signal is able to be supplied to a given device of the integrated circuit in each of said two or more configurations.
11. Method according to claim 1 , wherein
the method is executed by a system control processor separate from an application processor for processing general-purpose software.
12. Method according to claim 1 , wherein
the demand indication is received from an operating system or a device driver.
13. Method according to claim 1 , wherein
the demand indication is indicative of a range of clock frequencies for clock signals to be supplied to each device of the integrated circuit.
14. Non-transitory computer readable medium storing instructions that when executed by a computer system cause the computer system to perform the method of claim 1 .
15. Apparatus for configuring a clock distribution system for an integrated circuit, the apparatus comprising:
receiving circuitry to receive a demand indication indicative of demanded clock frequencies for clock signals to be supplied to one or more devices of the integrated circuit;
selecting circuitry to select a selected configuration of the clock distribution system in accordance with the demand indication; and
output circuitry to provide a configuration indication for configuring the clock distribution system according to the selected configuration; wherein
when a plurality of configurations of the clock distribution system are able to satisfy the demand indication, the selecting circuitry is configured to select the selected configuration from said plurality of configurations based on an estimated power consumption associated with said plurality of configurations.