Altera cyclone V Technical Reference page 759

cv_5v4
2016.10.28
Field
Protection
Fail/allow
Each port has a default access status of either allow or fail. Rules with the opposite allow/fail value can
override the default. The system evaluates each transaction against every rule in the memory protection
table. If a transaction arrives at a port that defaults to access allowed, it fails only if a rule with the fail bit
matches the transaction. Conversely, if a transaction arrives at a port that has the default rule set to access
denied, it allows access only if there is a matching rule that forces accessed allowed. Transactions that fail
the protection rules return a slave error (SLVERR).
The recommended sequence for writing a rule is:
1. Write the
•
ruleoffset
•
writerule
•
readrule
2. Write the
would like to enforce.
3. Write the
•
ruleoffset
•
writerule
•
readrule
Similarly, the recommended sequence for reading a rule is:
1. Write the
•
ruleoffset
•
writerule
•
readrule
2. Write the
•
ruleoffset
•
writerule
•
readrule
3. Read the values of the
parameters.
The following figure represents an overview of how the protection rules are applied. There is no priority
among the 20 rules. All rules are always evaluated in parallel.
SDRAM Controller Subsystem
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Width
2
1
register fields as follows:
protruledwr
= offset selected by user that points to indirect offset in an internal protection table..
= 0
= 0
,
protruleaddr protruleid
register fields as follows:
protruledwr
= offset of the rule that needs to be written
= 1
= 0
register fields as follows:
protruledwr
= offset of the rule that needs to be written
= 0
= 0
register fields as follows:
protruledwr
= offset of the rule that needs to be read
= 0
= 1
protruleaddr
A value of 0x0 indicates that the rule applies to secure
transactions; a value of 0x1 indicates the rule applies to non-
secure transactions. Values 0x2 and 0x3 set the region to
shared, meaning both secure and non-secure accesses are
Set this value to 1 to force the operation to fail or succeed.
, and registers so you configure the rule you
protruledata
, , and
protruleid protruledata
Memory Protection
Description
valid.
registers to determine the rule
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