Iem System Operation - Samsung S5PC110 Manual

S5PC110_UM

5.2.2 IEM SYSTEM OPERATION

Loading and starting the software
At an appropriate stage of system boot-up, the OS loads and initializes the modules that contain the IEM software:
•
On most platforms, the module loader automatically runs the initialization code for a module (if any)
•
Else, the OS (or a driver) must call the initialization codlmee itself.
This initialization code performs most of the set up for the IEM software. For example:
•
The code in the IEM HAL sets up and configures the performance scaling hardware
•
The code in the control component loads the Comms driver that it uses to communicate with the IEM kernel.
The OS then configures the IEM kernel by issuing commands to the control component. The control component
encodes these commands as messages, and uses the Comms driver to send them to the IEM kernel. These
control messages:
•
Start the policies, so that they are ready to use
•
Optionally:
−
Configure the IEM activities that are traced
−
Enables tracing.
Finally, the OS issues a command to start the IEM kernel. When the IEM kernel receives the corresponding
control message, it:
1. Allocates memory for the event queue, and initializes it.
2. Allocates memory for the IEM blocks, and initializes them.
3. Registers the kernel hooks that the OS calls whenever a system event occurs.
5 INTELLIGENT ENERGY MANAGEMENT
5-9