It is necessary to stop or complete any ongoing transactions by any IP or processor of the subsystem before resetting them. Otherwise, it can lead to hanging of the interconnect and eventually cause the entire system to hang. Additionally, to ensure proper operation by the IP after reboot, it is best to reset them and bring them to the post-BootROM state.
The PMU firmware implements peripheral idling and resetting for the PS IPs that can be idled or reset during the subsystem reset. The IPs that are attempted to be idled or reset depend on the isolation configuration of Vivado.
Build the PMU firmware with the following idling flags to enable subsystem node idling and resetting:
-
ENABLE_NODE_IDLING -
IDLE_PERIPHERALS
Node Reset and Idle
During a subsystem restart, the PMU firmware ensures that the associated PS peripheral nodes are idled and brought to the reset state. The following list includes currently supported PS peripherals that undergo idle/reset if they are part of the subsystem undergoing reset:
- TTC
- Ethernet/EMAC
- I2C
- SD
- eMMC
- QSPI
- USB
- DP
- SATA
See GPIO Reset to PL to understand the implications of GPIO reset.