arm64: dts: ti: k3-j721e-som-p0: Add DDR carveout memory nodes for C66 DSPs

arm64: dts: ti: k3-j721e-som-p0: Add DDR carveout memory nodes for C66 DSPs

Two carveout reserved memory nodes each have been added for each of the
C66x DSP remote processor devices present within the MAIN voltage domain
for the TI J721E EVM boards. These nodes are assigned to the respective
rproc device nodes as well. The first region will be used as the DMA pool
for the rproc devices, and the second region will furnish the static
carveout regions for the firmware memory.

The minimum granularity on the Cache settings on C66x DSP cores is 16 MB,
so the DMA memory regions are chosen such that they are in separate 16 MB
regions for each DSP, while reserving a total of 16 MB for each DSP and
not changing the overall DSP remoteproc carveouts.

The current carveout addresses and sizes are defined statically for each
device. The C66x DSP processors do not have an MMU, and as such require the
exact memory used by the firmwares to be set-aside. The firmware images
do not require any RSC_CARVEOUT entries in their resource tables to
allocate the memory for firmware memory segments.

The reserved memory nodes can be disabled later on if there is no use-case
defined to use the corresponding remote processor.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Reviewed-by: Lokesh Vutla <lokeshvutla@ti.com>
Link: https://lore.kernel.org/r/20200825172145.13186-5-s-anna@ti.com