Functional Description
11.3.10 Memory Protection
The EDMA3 channel controller supports two kinds of memory protection: active and proxy.
11.3.10.1 Active Memory Protection
Active memory protection is a feature that allows or prevents read and write accesses (by any EDMA3
programmer) to the EDMA3CC registers (based on permission characteristics that you program). Active
memory protection is achieved by a set of memory protection permissions attribute (MPPA) registers.
The EDMA3CC register map is divided into three categories:
•
a global region.
•
a global channel region.
•
eight shadow regions.
Each shadow region consists of the respective shadow region registers and the associated PaRAM. For
more detailed information regarding the contents of a shadow region, refer to section
Each of the eight shadow regions has an associated MPPA register (MPPAn) that defines the specific
requestor(s) and types of requests that are allowed to the regions resources.
The global channel region is also protected with a memory-mapped register (MPPAG). The MPPAG
applies to the global region and to the global channel region, except the other MPPA registers themselves.
For more detailed information on the list of the registers in each region, refer to the register memory-map
in section
See
for the bit field descriptions of MPPAn. The MPPAn have a certain set of access
rules.
shows the accesses that are allowed or not allowed to the MPPAG and MPPAn. The active
memory protection uses the PRIV and PRIVID attributes of the EDMA programmer. The PRIV is the
privilege level (i.e., user vs. supervisor). The PRIVID refers to a privilege ID with a number that is
associated with an EDMA3 programmer. See the device-specific data manual for the PRIVIDs that are
associated with potential EDMA3 programmers.
Table 11-17. Allowed Accesses
Access
Supervisor
User
Read
Yes
Yes
Write
Yes
No
describes the MPPA register mapping for the shadow regions (which includes shadow region
registers and PaRAM addresses).
The region-based MPPA registers are used to protect accesses to the DMA shadow regions and the
associated region PaRAM. Because there are eight regions, there are eight MPPA region registers
(MPPA[0-7]).
Table 11-18. MPPA Registers to Region Assignment
Register
Registers Protect
Address Range
PaRAM Protect
(1)
Address Range
MPPAG
Global Range
0000h-1FFCh
N/A
N/A
MPPA0
DMA Shadow 0
2000h-21FCh
1st octant
4000h-47FCh
MPPA1
DMA Shadow 1
2200h-23FCh
2nd octant
4800h-4FFCh
MPPA2
DMA Shadow 2
2400h-25FCh
3rd octant
5000h-57FCh
MPPA3
DMA Shadow 3
2600h-27FCh
4th octant
5800h-5FFCh
MPPA4
DMA Shadow 4
2800h-29FCh
5th octant
6000h-67FCh
MPPA5
DMA Shadow 5
2A00h-2BFCh
6th octant
6800h-6FFCh
MPPA6
DMA Shadow 6
2C00h-2DFCh
7th octant
7000h-77FCh
MPPA7
DMA Shadow 7
2E00h-2FFCh
8th octant
7800h-7FFCh
(1)
The PARAM region is divided into 8 regions referred to as an octant.
908 Enhanced Direct Memory Access (EDMA)
SPRUH73H – October 2011 – Revised April 2013
Copyright © 2011–2013, Texas Instruments Incorporated