Chapter 10 Memory Subsystem.pdf

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• NOfServices/ExtendedGrant have higher priority than the PWM counter.
• The PWM counter is reloaded with M and N when it reaches 1 and an arbitration decision must be
made.
• The priority order is as follows:
– Current burst service lock (assuming subsequent burst requests available when required)
– Class 0
– ExtendedGrant and NOfServices atomicity (assuming subsequent burst requests available when
required)
– Class 1 if PWM priority is to class 1; class 2 if PWM priority is to class 2
– Class 2 if PWM priority is to class 1; class 1 if PWM priority is to class 2
10.2.4.1.4 Firewalls
Access permissions can be defined in the target memory address space on a per-initiator basis. Initiators
are differentiated using the interconnect ConnID extension.
Permissions are allocated to the various initiators on a per-region basis. The memory regions are
programmable using a start address and an end address that are defined with 64K-byte granularity. Up to
seven distinct regions can be defined; the software must ensure that they do not overlap.
The remaining memory space (total memory space minus the protected areas) is defined as region 0.
Depending on whether the access is a read or a write, and depending on the in-band request qualifiers, a
region may be given specific access permissions. When an access is received by the SMS, the access
checked against the access attributes.
• The read permission is initiator-based and is controlled using the SMS.SMS_RG_RDPERMi register.
• The write permission is initiator-based and is controlled using the SMS.SMS_RG_WRPERMi register.
• The REQINFO bits taken into account are the incoming MReqInfo attributes: Debug, privilege, and
attribute, along with the host parameter decoded in the SMS module (see the
SMS.SMS_RG_ATTi[31:0] REQINFO field). For the SMS firewall, the host parameter is set for the
MPU initiator and the sDMA initiator. The decoding of the host parameter, based on the MPU ConnID
and sDMAConnID generic parameters (defined at design time), is done inside the SMS module.
• Whether the access is accepted (there is one valid bit for each ReqInfo pattern) can be specified for
each ReqInfo pattern. ReqInfo permission is controlled using the region attributes register
SMS.SMS_RG_ATTi[31:0] REQINFO field.
Table 10-99 lists the ReqInfo parameters ordering.
Table 10-99. ReqInfo Parameters Ordering
Host Privilege Reserved Debug Type Req SMS.SMS_RG_ATTi[31:0]
for Non-GP Info REQINFO Field
Devices
0: Nonhost 0: User Reserved 0: Functional 0: Data Transfer
1: Host 1: Supervisor 1: Debug 1: Opcode Fetch
N/A (1)
0b0...000000000
0 0 0 0 0 0 0b0...000000001
0 0 0 0 0 1 0b0...000000010
0 0 0 1 0 2 0b0...000000100
0 1 1 1 0 14 0b0...000001...00
0 1 1 1 1 15 0b0...00001...000
1 0 0 0 0 16 0b0...0001...0000
1 0 0 0 1 17 0b0...001...00000
1 1 1 0 1 29 0b0010...000000
1 1 1 1 0 30 0b0100...000000
1 1 1 1 1 31 0b1000...000000
(1) Access to the region is not allowed
SPRUGN4L–May 2010–Revised June 2011 Memory Subsystem2223
Copyright © 2010–2011, Texas Instruments Incorporated
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