linux-phytec-ti

ARM: dts: AM4372: Add the PRU-ICSS1 DT node

Add the DT node for the PRU-ICSS1 instance on the AM437x family
of SoCs. The PRU-ICSS instances are not supported on AM4372 SoC
though in the AM437x family, so the nodes are added in disabled
state in the common am4372 dtsi file. They should be enabled only
for boards that use a SoC containing PRU-ICSS in the derivative
board files.

The DT node uses all standard properties. The regs property
defines the addresses for various modules within the PRUSS,
including all the Data RAMs, the Instruction RAM per core,
the INTC, the Industrial Ethernet Peripheral (IEP), the
Real Time Media Independent Interface controller (MII_RT),
CFG, Debug and Control sub-modules.

The two PRU cores within the PRUSS and the interrupt controller
are represented as child nodes (so platform devices themselves)
of the PRUSS parent node. The default support for virtio/rpmsg
communication between MPU and a PRU core is provided through PRU
system events instead of OMAP mailboxes. This is the preferred
approach as there are not enough mailboxes on AM437x SoCs to
support all PRU cores, and it also eliminates an external
peripheral access from the PRU-side.

The PRU-ICSS1 on AM437x is very similar to the PRUSS in AM33xx,
except for variations in the RAM sizes, bus addresses and the
number of interrupts coming into the MPU INTC (host interrupt
7 is routed to the other PRUSS instead of MPU).

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Keerthy <j-keerthy@ti.com>