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Diffstat (limited to 'fpga/usrp3/lib/rfnoc/utils/ctrlport_splitter.v')
| -rw-r--r-- | fpga/usrp3/lib/rfnoc/utils/ctrlport_splitter.v | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/fpga/usrp3/lib/rfnoc/utils/ctrlport_splitter.v b/fpga/usrp3/lib/rfnoc/utils/ctrlport_splitter.v new file mode 100644 index 000000000..23ef13585 --- /dev/null +++ b/fpga/usrp3/lib/rfnoc/utils/ctrlport_splitter.v @@ -0,0 +1,114 @@ +// +// Copyright 2019 Ettus Research, A National Instruments Company +// +// SPDX-License-Identifier: LGPL-3.0-or-later +// +// Module: ctrlport_splitter +// +// Description: +// +// This block splits a single control port interface into multiple. It is used +// when you have a single master that needs to access multiple slaves. For +// example, a NoC block where the registers are implemented in multiple +// submodules that must be read/written by a single NoC shell. +// +// Note that this block does not do any address decoding, so the connected +// slaves must use non-overlapping address spaces. +// +// This module takes the request received by its single slave interface and +// outputs it on all its master interfaces. In the opposite direction, it takes +// the responses received by its multiple master interfaces and combines them +// into a single response on its slave interface. This is done by using the ack +// bit of each response to mask the other bits of the response, then OR'ing all +// of the masked responses together onto a single response bus. This is valid +// because only one block is allowed to respond to a single request. +// +// Parameters: +// +// NUM_SLAVES : The number of slaves you want to connect to a master. +// + + +module ctrlport_splitter #( + parameter NUM_SLAVES = 2 +) ( + input wire ctrlport_clk, + input wire ctrlport_rst, + + // Slave Interface + input wire s_ctrlport_req_wr, + input wire s_ctrlport_req_rd, + input wire [19:0] s_ctrlport_req_addr, + input wire [31:0] s_ctrlport_req_data, + input wire [ 3:0] s_ctrlport_req_byte_en, + input wire s_ctrlport_req_has_time, + input wire [63:0] s_ctrlport_req_time, + output reg s_ctrlport_resp_ack = 1'b0, + output reg [ 1:0] s_ctrlport_resp_status, + output reg [31:0] s_ctrlport_resp_data, + + // Master Interfaces + output wire [ NUM_SLAVES-1:0] m_ctrlport_req_wr, + output wire [ NUM_SLAVES-1:0] m_ctrlport_req_rd, + output wire [20*NUM_SLAVES-1:0] m_ctrlport_req_addr, + output wire [32*NUM_SLAVES-1:0] m_ctrlport_req_data, + output wire [ 4*NUM_SLAVES-1:0] m_ctrlport_req_byte_en, + output wire [ NUM_SLAVES-1:0] m_ctrlport_req_has_time, + output wire [64*NUM_SLAVES-1:0] m_ctrlport_req_time, + input wire [ NUM_SLAVES-1:0] m_ctrlport_resp_ack, + input wire [ 2*NUM_SLAVES-1:0] m_ctrlport_resp_status, + input wire [32*NUM_SLAVES-1:0] m_ctrlport_resp_data +); + + //--------------------------------------------------------------------------- + // Split the requests among the slaves + //--------------------------------------------------------------------------- + + generate + genvar i; + for (i = 0; i < NUM_SLAVES; i = i+1) begin : gen_split + // No special logic is required to split the requests from the master among + // multiple slaves. + assign m_ctrlport_req_wr[i] = s_ctrlport_req_wr; + assign m_ctrlport_req_rd[i] = s_ctrlport_req_rd; + assign m_ctrlport_req_addr[20*i+:20] = s_ctrlport_req_addr; + assign m_ctrlport_req_data[32*i+:32] = s_ctrlport_req_data; + assign m_ctrlport_req_byte_en[4*i+:4] = s_ctrlport_req_byte_en; + assign m_ctrlport_req_has_time[i] = s_ctrlport_req_has_time; + assign m_ctrlport_req_time[64*i+:64] = s_ctrlport_req_time; + end + endgenerate + + //--------------------------------------------------------------------------- + // Decode the responses + //--------------------------------------------------------------------------- + + reg [31:0] data; + reg [ 1:0] status; + reg ack = 0; + + // Take the responses and mask them with ack, then OR them together + always @(*) begin : comb_decode + integer s; + data = 0; + status = 0; + ack = 0; + for (s = 0; s < NUM_SLAVES; s = s+1) begin + data = data | (m_ctrlport_resp_data [s*32 +: 32] & {32{m_ctrlport_resp_ack[s]}}); + status = status | (m_ctrlport_resp_status[s* 2 +: 2] & { 2{m_ctrlport_resp_ack[s]}}); + ack = ack | m_ctrlport_resp_ack[s]; + end + end + + // Register the output to break combinatorial path + always @(posedge ctrlport_clk) begin + if (ctrlport_rst) begin + s_ctrlport_resp_ack <= 0; + end else begin + s_ctrlport_resp_data <= data; + s_ctrlport_resp_status <= status; + s_ctrlport_resp_ack <= ack; + end + end + +endmodule |