Two carveout reserved memory nodes each have been added for each of the
R5F remote processor devices within the MAIN domain on the TI AM642 EVM
and SK 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.

An additional reserved memory node is also added to reserve a portion of
the DDR memory to be used for performing inter-processor communication
between all the remote processors running RTOS or baremetal firmwares.
8 MB of memory is reserved for this purpose, and this accounts for all
the vrings and vring buffers between all the possible pairs of remote
processors.

The current carveout addresses and sizes are defined statically for each
rproc device. The R5F 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.

NOTE:
1. The R5F1 carveouts are needed only if the R5F cluster is running in
   Split (non Single-CPU) mode. The reserved memory nodes can be disabled
   later on if there is no use-case defined to use the corresponding
   remote processor.
2. The AM64x SoCs do not have any DSPs and one less R5F cluster compared
   to J721E SoCs. So, while the carveout memories reserved for the R5F
   clusters present on the SoC match to those on J721E, the overall
   memory map reserved for firmwares is quite different. The number of
   R5F clusters on AM64x SoCs are same as on J7200 SoCs, but the AM64x
   SoCs also have an additional M4F core, so the RTOS IPC memory region
   is 1 MB higher than on J7200 SoCs.
Signed-off-by: Suman Anna <s-anna@ti.com>
Reviewed-by: Praneeth Bajjuri <praneeth@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>
Link: https://lore.kernel.org/r/20210615195718.15898-4-s-anna@ti.com