DSP Memory Management Unit
2-47
MPU Subsystem
2.8
DSP Memory Management Unit
The DSP MMU handles the external memory space mapping of the DSP in the
entire shared memory space of the OMAP5910 device. The DSP MMU trans-
lates addresses coming from the DSP (virtual address) to addresses mapped
by the traffic controller. The MMU is used when the DSP software accesses
external memory. This memory can be any mapped on the OMAP5910
address space, on the internal SRAM, or on an external SDRAM.
The DSP MMU sees 16M bytes of virtual program and 16M bytes of virtual data
spaces. The 16M bytes of DSP external addresses can be mapped to any of
the 4G bytes of addresses on the OMAP5910 device. If a memory protection
or memory access violation occurs, the DSP MMU sends an interrupt to the
MPU via the second-level interrupt handler on IRQ_28. Information about the
violation can be found in the MMU fault address and fault status registers.
The DSP MMU is programmed by the TI925T processor. In general, the MMU
is initialized at boot time, but it also can be reprogrammed dynamically. The
MMU is programmed through the TI peripheral bus registers. The DSP MMU
registers are listed in Table 2–26 and detailed in this section.
Table 2–26. DSP Memory Management Unit Registers
Name
Description
R/W
Size
Address
Reset Value
PREFETCH_REG
Prefetch register
R/W
16 bits FFFE:D200
0x0000
WALKING_ST_REG
Prefetch status register
R
16 bits FFFE:D204
0x0000
CNTL_REG
Control register
R/W
16 bits FFFE:D208
0x0000
FAULT_AD_H_REG
Fault address register MSB
R
16 bits FFFE:D20C
0x0000
FAULT_AD_L_REG
Fault address register LSB
R
16 bits FFFE:D210
0x0000
F_ST_REG
Fault status register
R
16 bits FFFE:D214
0x0000
IT_ACK_REG
Interrupt acknowledge register
W
16 bits FFFE:D218
0x0000
TTB_H_REG
TTB register MSB
R/W
16 bits FFFE:D21C
0x0000
TTB_L_REG
TTB register LSB
R/W
16 bits FFFE:D220
0x0000
LOCK_REG
Lock counter
R/W
16 bits FFFE:D224
0x0000
LD_TLB_REG
Load entry in TLB
R/W
16 bits FFFE:D228
0x0000
CAM_H_REG
CAM entry register MSB
R/W
16 bits FFFE:D22C
0x0000
CAM_L_REG
CAM entry register LSB
R/W
16 bits FFFE:D230
0x0000
RAM_H_REG
RAM entry register MSB
R/W
16 bits FFFE:D234
0x0000