GR740-UM-DS, Nov 2017, Version 1.7
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GR740
When a failure occurs during a bus access, the error code is set to 1 (General Error). There is a prede-
termined order in which error-codes are set in the case of multiple errors. It is shown in table 152.
Read accesses are performed on the fly, that is, they are not stored in a temporary buffer before trans-
mission. This means that the error code 1 will never be seen in a read reply since the header has
already been sent when the data is read. If an AHB error occurs, the packet is truncated and termi-
nated with an EEP.
Errors up to and including Invalid Data CRC (number 8) are checked before verified commands. The
other errors do not prevent verified operations from being performed.
Support for the different commands is described in the following subsections. All defined commands,
which are received with an unsupported option set are not executed and a possible reply is sent with
error code 10.
13.4.6.3 Write commands
The write commands are divided into two subcategories: verified writes and non-verified writes. Ver-
ified writes have a length restriction of 4 bytes and the address must be aligned to the size. Thus, 1
byte writes can be done to any address, 2 bytes writes must be halfword aligned, 3 bytes writes are not
allowed and 4 bytes writes must be word aligned. Since there will always be only one AHB operation
performed for each RMAP verified write command, the incrementing address bit can be set to any
value.
Non-verified writes have no restrictions when the incrementing bit is set to 1. If it is set to 0, the num-
ber of bytes must be a multiple of 4 and the address word aligned. There is no guarantee how many
words are written when early EOP/EEP is detected for non-verified writes.
13.4.6.4 Read commands
Read commands are performed on the fly when the reply is sent. Thus, if an AHB error occurs the
packet is truncated and terminated with an EEP. There are no restrictions for incrementing reads but
non-incrementing reads have the same alignment restrictions as non-verified writes. Note that the
“Authorization failure” error code will be sent in the reply if a violation was detected even if the
length field was zero. Also note that no data is sent in the reply if an error was detected, i.e. if the sta-
tus field is non-zero.
Table 152.
The order of error detection in case of multiple errors. The error detected first has number 1.
Detection Order
Error Code
Error
1
12
Invalid destination logical address
2
2
Unused RMAP packet type or command code
3
3
Invalid destination key
4
9
Verify buffer overrun
5
11
RMW data length error
6
10
Authorization failure
7*
1
General Error (AHB errors during non-verified writes)
8
5/7
Early EOP / EEP (if early)
9
4
Invalid Data CRC
10
1
General Error (AHB errors during verified writes or RMW)
11
7
EEP
12
6
Too Much Data
*The AHB error is not guaranteed to be detected before Early EOP/EEP or Invalid Data CRC. For very long accesses
the AHB error detection might be delayed causing the other two errors to appear first.