Port Channel Scheduling; Time Sharing Access On A System Dma Port - Texas Instruments OMAP5912 Reference Manual

Table 19. Possible Data Transfer
3.1.5

Port Channel Scheduling

Figure 4.

Time Sharing Access on a System DMA Port

SPRU755B
SRC EMIFS
EMIFS Yes
EMIFF Yes
OCP-T1 Yes
OCP-T2 Yes
TIPB bridge Yes
MPUI Yes
1
LCD No
†
Used for the OMAP internal LCD controller.
The port to use for source respective destination is configured in the channel
source destination parameters register, DMA_CSDP. The data type is also
configured in this register.
Note:
No address space check is performed by the system DMA. All addressing
outside the source and destination memory space causes undefined effects.
Each DMA logical channel can be configured independently from other logical
channels. Each DMA physical channel can have its own port or share it with
other physical channels. If physical channels share a DMA port, a port arbiter
prioritizes physical channel access.
The system DMA port arbiters follow a round robin scheme.
In Figure 4, a DMA port services three DMA physical channel requests:
Physical channel 0 as a source port (read requests r
-
Physical channel 1 as a destination port (write requests w
-
Physical channel 2 as a destination port (write requests w
-
r , r
0 0
Requests
w , w , w
waiting for
1 1
service
w , w , w
2 2
DST
EMIFF OCP-T1 OCP-T2 TIPB
Yes Yes Yes
Yes Yes Yes
Yes Yes Yes
Yes Yes Yes
Yes Yes Yes
Yes Yes Yes
No No No
, r
0
Port
1
2
Direct Memory Access (DMA) Support
System DMA
MPUI LCD
Bridge
Yes Yes No
Yes Yes Yes
Yes Yes Yes
Yes Yes Yes
Yes Yes No
Yes Yes No
No No No
)
0
)
1
)
2
Requests served
w , w , r , w , w , r , w , w
2 1 0 2 1 0 2
1
, r
1 0
37