A.5.1 Bridge upstream signals

The upstream side of each bridge component (ACG, SDB, or SUB) has an AXI5 slave interface. Bridge components also have an external-gating interface, two configuration signals, and two Q-Channel device interfaces.

The following tables list the clock and reset signals for the upstream side of each bridge component.

Table A-34 ACG upstream clock and reset signals

Signal Direction Description
aclk_s Input Clock
aresetn_s Input Active-LOW reset. Reset can go LOW asynchronously but must go HIGH synchronously.

Table A-35 SDB upstream clock and reset signals

Signal Direction Description
aclk_s Input Clock
aresetn_s Input Active-LOW reset. Reset can go LOW asynchronously but must go HIGH synchronously.
aclk_en_s Input Clock enable signal that enables the AXI5 slave interface to operate at either:
  • The aclk_s frequency.
  • A divided integer multiple of aclk_s that is aligned to aclk_s.

Table A-36 SUB upstream clock and reset signals

Signal Direction Description
aclk_s Input Clock
aresetn_s Input Active-LOW reset. Reset can go LOW asynchronously but must go HIGH synchronously.

The following table lists the AXI5 slave interface signals.

Table A-37 Bridge upstream AXI5 slave interface signals

Signal Direction Description
AW channel signals:
awvalid_s Input Write address valid signal.
awaddr_s[ADDR_WIDTH−1:0] Input Write address signal.
awburst_s[1:0] Input Write burst type signal.
awid_s[ID_WIDTH−1:0] Input Write request ID signal.
awlen_s[7:0] Input Write burst length signal.
awsize_s[2:0] Input Write burst size signal.
awlock_s Input Write lock type signal.
awprot_s[2:0] Input Write protection type signal.
awready_s Output Write address ready signal.
awcache_s[3:0] Input Indicates how transactions are required to progress through a system.
awqos_s[3:0] Input QoS identifier.
awregion_s[3:0] Input Permits a single physical interface on a slave to be used for multiple logical interfaces.
awuser_s[AWUSER_WIDTH−1:0] Input Write address channel User signal.
AR channel signals:
arvalid_s Input Read address valid signal.
araddr_s[ADDR_WIDTH−1:0] Input Read address signal.
arburst_s[1:0] Input Read burst type signal.
arid_s[ID_WIDTH−1:0] Input Read request ID signal.
arlen_s[7:0] Input Read address burst length signal.
arsize_s[2:0] Input Read burst size signal.
arlock_s Input Read lock type signal.
arprot_s[2:0] Input Read protection type signal.
arready_s Output Read address ready signal.
arcache_s[3:0] Input Indicates how transactions are required to progress through a system.
arqos_s[3:0] Input QoS identifier.
arregion_s[3:0] Input Permits a single physical interface on a slave to be used for multiple logical interfaces.
aruser_s[ARUSER_WIDTH−1:0] Input Read address channel User signal.
W channel signals:
wvalid_s Input Write data valid signal.
wlast_s Input Indicates last transfer in a write burst.
wstrb_s[(DATA_WIDTH/8)−1:0] Input Write byte lane strobes.
wdata_s[DATA_WIDTH−1:0] Input Write data signal.
wpoison_s[(DATA_WIDTH−1)/64:0] Input 64-bit data granule corruption indicator.
wuser_s[WUSER_WIDTH−1:0] Input Write data User signal.
wready_s Output Write data ready signal.
R channel signals:
rvalid_s Output Read data valid signal.
rid_s[ID_WIDTH−1:0] Output Read data ID.
rlast_s Output Indicates last transfer in read data.
rdata_s[DATA_WIDTH−1:0] Output Read data.
rresp_s[1:0] Output Read data response.
rready_s Input Read data ready signal.
ruser_s[RUSER_WIDTH−1:0] Output Read data User signal.
rpoison_s[(DATA_WIDTH−1)/64:0] Output 64-bit data granule corruption indicator.
B channel signals:
bvalid_s Output Write response valid signal.
bid_s[ID_WIDTH−1:0] Output Write response ID signal.
buser_s[BUSER_WIDTH−1:0] Output Write response User signal.
bresp_s[1:0] Output Write response signal.
bready_s Input Write response ready signal.

The following table lists the wakeup signals.

Table A-38 Bridge upstream wakeup signals

Signal Direction Description
awakeup_s Input When this signal is HIGH, it indicates that the AXI master is initiating activity on this interface.
pwr_wake_qactive_m Output A wakeup indication towards the downstream PPU. The PPU can then wake up the downstream side of the bridge by driving the pwr_qreqn_m signal.

The following table lists the external gating configuration signals.

Table A-39 Bridge upstream external gating configuration signals

Signal Direction Description
cfg_gate_resp Input

Controls how the bridge component responds to AXI transactions, when the downstream side of the AXI5 bridge is in external gating or power quiescence.

When cfg_gate_resp is:

0 = the bridge component stalls the transaction until the external gating and power quiescence on each side of the bridge is released.

1 = the bridge component responds with an ERROR response.

You can change the value of cfg_gate_resp during operation. The bridge component samples cfg_gate_resp during the first clock cycle of an incoming transaction, when arvalid_s or awvalid_s is HIGH.

Note:

Do not tie cfg_gate_resp HIGH, otherwise the bridge becomes stuck in a closed state.
cfg_ext_gt_err_resp Input

Controls how the bridge component responds to AXI transactions, when the upstream external gating is in quiescence.

When cfg_ext_gt_err_resp is:

0 = no effect. The cfg_gate_resp value controls the response behavior.

1 = forced error response. The bridge component accepts all currently stalled transactions and responds with an ERROR response.

You can change the value of cfg_ext_gt_err_resp during operation only when upstream external gating request is not asserted. The bridge component samples cfg_ext_gt_err_resp at the first clock cycle of upstream external gating quiescence, and is in effect only during upstream external gating quiescence.

The following table lists the external-gating signals. See 6.6 External gating of the AXI interface (upstream) for more information.

Table A-40 Bridge upstream external gating signals

Signal Direction Description
ext_gt_qreqn_s Input This signal indicates when a controller issues an external-gating entry or exit request to the bridge component.
ext_gt_qacceptn_s Output This signal indicates when the bridge component accepts the external gating request.

The following table lists the Q-Channel device signals.

Table A-41 Bridge upstream Q-Channel signals

Signal Direction Description
Clock control Q-Channel device signals:
clk_qreqn_s Input This signal indicates when the controller issues a quiescence entry or exit request to the bridge component.
clk_qacceptn_s Output This signal indicates when the bridge component accepts the quiescence request.
clk_qdeny_s Output This signal indicates when the bridge component denies the quiescence request.
clk_qactive_s Output This signal indicates when the bridge component is active and also when it requests to exit from quiescence.
Power control Q-Channel device signals:
pwr_qreqn_s Input This signal indicates when the controller issues a quiescence entry or exit request to the bridge component.
pwr_qacceptn_s Output This signal indicates when the bridge component accepts the quiescence request.
pwr_qdeny_s Output This signal indicates when the bridge component denies the quiescence request.
pwr_qactive_s Output This signal indicates when the bridge component is active and also when it requests to exit from quiescence.
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