Dsp Subsystem External Memory Interface; Software Configuration - Texas Instruments OMAP5910 Reference Manual

Figure 47.

DSP Subsystem External Memory Interface

6.4.2

Software Configuration

SPRU890A
3) The MMU checks its TLB for a match on the virtual address tag. If there
is a TLB hit and the correct access permissions for the type of access (read
or write) are found, the MMU translates the virtual address from the EMIF
into a physical address and forwards the request to the traffic controller
with the appropriate endianess conversion.
Otherwise, if the virtual address tag is not found, the MMU uses its table
walking logic to fetch the translation from translation tables and updates
the TLB. If correct access permissions are found, the MMU carries out the
virtual-to-physical address translation and forwards the request to the
traffic controller. If the correct access permissions are not found, MMU
generates an interrupt to the MPU core and stalls the DSP EMIF until the
error is cleared. When the MPU core clears this error, the DSP MMU
repeats this entire step.
4) The traffic controller accesses the actual OMAP resource.
Figure 47 shows the major blocks involved during an access to DSP external
memory by the DSP subsystem.
OMAP device
DSP subsystem
Requestors
DMA
DSP core
data buses
DSP core
program buses
The DSP MMU is initialized by the MPU core. To prevent a DSP access to DSP
external memory while the MMU is disabled, it is recommended that the MMU
be initialized and enabled before the DSP subsystem is taken out of reset.
DSP Memory Management Unit
DSP MMU
Addr. Addr.
Address
conversion
Data Data
Endianess
conversion
Access
checking
DSP Subsystem
Resources
IMIF
Internal
SRAM
Traffic
controller
EMIFS
Flash
EMIFF
SDRAM
99