Intel® Stratix® 10 Hard Processor System Technical Reference Manual

ID 683222
Date 11/28/2022
Public

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4.7.3. Specifying Address Ranges for Slave Devices

You can program each master to access different slave ranges and access privileges. You can also configure memory as shared or non-shared for different masters depending on how you program the Address Base (*am_adbase*) registers.
By programming the Address Base registers (*am_adbase*) and the Address Mask registers (*am_admask*), you can specify lower and upper-bound addresses for each slave a master is accessing. You must configure address ranges at a 64 byte cache line boundary because the lower six bits of these registers specify access permissions for the address range. Each master can have a different valid slave access range and different access privileges. An address on the AR or AW channel matches against a range if the address satisfies the equation:
AxAddress & AM_ADMASK[i] == AM_ADBASE[i]
where i represents a register bit.

You can program address ranges as disabled, read-only, or write-only. During address decode, the CCU compares ARPROT or AWPROT signals with the access privilege programmed for an address range. A failed access check results in a decode error response for the transaction.

  1. Program the following fields in a bridge's *am_adbase* register:
    Table 48.  *am_adbase* Register Field Settings
    *am_adbase* Register Bitfield Configuration Description
    BASE_ADDRESS The base address value must be a factor of the address mask value. The base address register bitfields must not have a 1 where a corresponding mask bit is 0.
    Note: To prevent access errors, ensure that the *am_adbase* base address lies within the slave's valid address range.
    DI Set this bit if you are configuring this address range to be disabled.
    R_Wn Set this bit to make this address range readable; clear this bit to make it writable.
    I Set this bit if this address range holds instructions.
    NS Set this bit to make the address range non-secure; clear this bit to make the address range secure.
    P Set this bit to indicate if this range is only available through a privileged access.
  2. Program the corresponding *am_admask* register.

    Bits [2:0] of *am_adbase* and *am_admask* act as a value and mask for checking against the AxPROT of an incoming command. The CCU allows a command access to a range if

    AxPROT & *am_admask*[2:0] == *am_adbase*[2:0] & *am_admask*[2:0]
    If the above check fails, then the CCU denies the command access to the range and returns a decode error response. For any access, you can selectively disable an address range or designate the access as read-only or write-only access using *am_adbase*[4:3] and *am_admask*[3]. The table below details the encodings.
    Table 49.  Address Range Access
    Note: An X in this table denotes a "don't care."
    *am_adbase*[4]-DI *am_admask*[3]-VALID *am_adbase*[3]-R_Wn Access
    1 X X Range disabled
    0 1 1 Read only
    0 1 0 Write only
    0 0 X Read/write