Wakeup M3 IPC Driver
The TI AM33xx and AM43xx family of devices use a small Cortex M3 co-processor
(commonly referred to as Wakeup M3 or CM3) to help with various low power tasks
that cannot be controlled from the MPU, like suspend/resume and certain deep
C-states for CPU Idle. Once the wkup_m3_ipc driver uses the wkup_m3_rproc driver
to boot the wkup_m3, it handles communication with the CM3 using IPC registers
present in the SoC’s control module and a mailbox. The wkup_m3_ipc exposes an
API to allow the SoC PM code to execute specific PM tasks.
Wkup M3 Device Node:
A wkup_m3_ipc device node is used to represent the IPC registers within an
SoC.
Required properties:
- compatible: Should be,
"ti,am3352-wkup-m3-ipc" for AM33xx SoCs "ti,am4372-wkup-m3-ipc" for AM43xx SoCs - reg: Contains the IPC register address space to communicate
with the Wakeup M3 processor - interrupts: Contains the interrupt information for the wkup_m3
interrupt that signals the MPU. - ti,rproc: phandle to the wkup_m3 rproc node so the IPC driver
can boot it. - mboxes: phandles used by IPC framework to get correct mbox
channel for communication. Must point to appropriate mbox_wkupm3 child node.
Example:
/* AM33xx */
l4_wkup: l4_wkup@44c00000 {
…
scm: scm@210000 {
compatible = "ti,am3-scm", "simple-bus";
reg = <0x210000 0x2000>;
#address-cells = <1>;
#size-cells = <1>;
ranges = <0 0x210000 0x2000>;
...
wkup_m3_ipc: wkup_m3_ipc@1324 {
compatible = "ti,am3352-wkup-m3-ipc";
reg = <0x1324 0x24>;
interrupts = <78>;
ti,rproc = <&wkup_m3>;
mboxes = <&mailbox &mbox_wkupm3>;
};
...
};
};
