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axi_lite_dw_converter: Enable user size pass from AXI converter
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@paulsc96 @thommythomaso
paulsc96 authored and thommythomaso committed Jul 25, 2023
1 parent da42383 commit e19dc09
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Showing 2 changed files with 166 additions and 31 deletions.
174 changes: 145 additions & 29 deletions src/axi_lite_dw_converter.sv
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Original file line number Diff line number Diff line change
Expand Up @@ -66,6 +66,18 @@ module axi_lite_dw_converter #(
parameter int unsigned AxiSlvPortDataWidth = 32'd0,
/// AXI4-Lite data width of the master port.
parameter int unsigned AxiMstPortDataWidth = 32'd0,
/// Whether to read a transaction size from the AR user bits
parameter bit UserArSize = 1'b0,
/// Whether to read a transaction size from the AW user bits
parameter bit UserAwSize = 1'b0,
/// Least significant bit (LSB) of size in AR user fields
parameter int unsigned UserArSizeLsb = 32'd0,
/// Least significant bit (LSB) of size in AW user fields
parameter int unsigned UserAwSizeLsb = 32'd0,
/// Assuming AW size in user field, maximum number of inflight reads.
parameter int unsigned UserArMaxTxns = 32'd0,
/// Assuming AW size in user field, maximum number of inflight writes.
parameter int unsigned UserAwMaxTxns = 32'd0,
/// AXI4-Lite AW channel struct type. This is for both ports the same.
parameter type axi_lite_aw_t = logic,
/// AXI4-Lite W channel struct type of the slave port.
Expand Down Expand Up @@ -132,6 +144,7 @@ module axi_lite_dw_converter #(
// Input spill register of the AW channel.
axi_lite_aw_t aw_chan_spill;
logic aw_chan_spill_valid, aw_chan_spill_ready;
logic w_progress, aw_progress, b_progress;

spill_register #(
.T ( axi_lite_aw_t ),
Expand All @@ -147,19 +160,35 @@ module axi_lite_dw_converter #(
.data_o ( aw_chan_spill )
);

sel_t aw_sel_q, aw_sel_d;
sel_t aw_sel_q, aw_sel_d, aw_sel_out;
logic aw_sel_load;
// AW channel output assignment
always_comb begin : proc_aw_chan_oup
mst_req_o.aw = aw_chan_spill;
mst_req_o.aw.addr = out_address(aw_chan_spill.addr, aw_sel_q);
mst_req_o.aw.addr = out_address(aw_chan_spill.addr, aw_sel_out);
end

assign aw_progress = aw_chan_spill_valid & mst_res_i.aw_ready;

if (UserAwSize) begin : gen_user_aw
// Couple AW, W, and B FIFO and make requests selectively
sel_t aw_sel_end, aw_sel_base;
assign aw_sel_end = UserAwSize ?
(sel_t'(1) << aw_chan_spill.user[UserAwSizeLsb:+axi_pkg::SizeWidth]) >> SelOffset : '0;
assign aw_sel_base = aw_chan_spill.aw.addr[SelOffset+:SelWidth] & sel_t'(aw_sel_end -1);
assign aw_sel_out = aw_sel_q + aw_sel_base;
assign mst_req_o.aw_valid = w_progress & b_progress & aw_chan_spill_valid;
assign aw_chan_spill_ready = w_progress & b_progress & mst_res_i.aw_ready &
((&aw_sel_q) | (aw_sel_d == aw_sel_end));
end else begin : gen_no_user_aw
// AW, W, and B are uncoupled
assign aw_sel_out = aw_sel_q;
assign mst_req_o.aw_valid = aw_chan_spill_valid;
assign aw_chan_spill_ready = mst_res_i.aw_ready & (&aw_sel_q);
end
// Slave port aw is valid, if there is something in the spill register.
assign mst_req_o.aw_valid = aw_chan_spill_valid;
assign aw_chan_spill_ready = mst_res_i.aw_ready & (&aw_sel_q);

assign aw_sel_load = mst_req_o.aw_valid & mst_res_i.aw_ready;
assign aw_sel_d = sel_t'(aw_sel_q + 1'b1);
assign aw_sel_d = sel_t'(aw_sel_load ? '0 : aw_sel_q + 1'b1);
`FFLARN(aw_sel_q, aw_sel_d, aw_sel_load, '0, clk_i, rst_ni)

// Input spill register of the W channel.
Expand All @@ -180,41 +209,82 @@ module axi_lite_dw_converter #(
);

// Data multiplexer on the W channel
sel_t w_sel_q, w_sel_d;
logic w_sel_load;
sel_t w_sel;
// W channel output assignment
assign mst_req_o.w = axi_lite_mst_w_t'{
data: w_chan_spill.data[w_sel_q*AxiMstPortDataWidth+:AxiMstPortDataWidth],
strb: w_chan_spill.strb[w_sel_q*AxiMstPortStrbWidth+:AxiMstPortStrbWidth],
data: w_chan_spill.data[w_sel*AxiMstPortDataWidth+:AxiMstPortDataWidth],
strb: w_chan_spill.strb[w_sel*AxiMstPortStrbWidth+:AxiMstPortStrbWidth],
default: '0
};
assign mst_req_o.w_valid = w_chan_spill_valid;
assign w_chan_spill_ready = mst_res_i.w_ready & (&w_sel_q);

assign w_sel_load = mst_req_o.w_valid & mst_res_i.w_ready;
assign w_sel_d = sel_t'(w_sel_q + 1'b1);
`FFLARN(w_sel_q, w_sel_d, w_sel_load, '0, clk_i, rst_ni)
assign w_progress = w_chan_spill_valid & mst_res_i.w_ready;

if (UserAwSize) begin : gen_user_aw_w
// We must couple the AW, W, and B FIFO; adopt AW channel counts here
assign mst_req_o.w_valid = aw_progress & b_progress & w_chan_spill_valid;
assign w_chan_spill_ready = aw_progress & b_progress & mst_res_i.w_ready;
assign w_sel = aw_sel_out;
end else begin : gen_no_user_aw_w
// The W channel can operate uncoupled
sel_t w_sel_q, w_sel_d;
logic w_sel_load;
assign w_sel_load = mst_req_o.w_valid & mst_res_i.w_ready;
assign w_sel_d = sel_t'(w_sel_q + 1'b1);
`FFLARN(w_sel_q, w_sel_d, w_sel_load, '0, clk_i, rst_ni)
assign mst_req_o.w_valid = w_chan_spill_valid;
assign w_chan_spill_ready = mst_res_i.w_ready & (&w_sel_q);
assign w_sel = w_sel_q;
end

// B response aggregation
// Slave port B output is the aggregated error of the last few B responses.
sel_t b_sel_q, b_sel_d;
axi_pkg::resp_t b_resp_q, b_resp_d;
logic b_resp_load;
logic b_end;

assign slv_res_o.b = axi_lite_b_t'{
resp: b_resp_q | mst_res_i.b.resp,
default: '0
};

if (UserAwSize) begin : gen_user_aw_b
// When an upstream AW/W pair completes, store the expected downstream B count
sel_t b_out;
stream_fifo #(
.FALL_THROUGH ( 1'b0 ),
.DEPTH ( UserAwMaxTxns ),
.T ( sel_t ),
) i_b_count_fifo (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( 1'b0 ),
.usage_o ( ),
.data_i ( aw_sel_out ),
.valid_i ( mst_req_o.aw_valid & mst_resp_i.aw_ready ),
.ready_o ( b_progress ),
.data_o ( b_out ),
.valid_o ( ), // TODO: Assert true when B comes in (`b_resp_load`)
.ready_i ( b_end )
);
assign b_end = (&b_sel_q) | (b_sel_d == b_out);
end else begin : gen_no_user_aw_b
// Simply count payloads as for AW and W
assign b_end = (&b_sel_q);
assign b_progress = 1'b1;
end

// Output is valid, if it is the last b response for the wide W, we have something
// in the B FIFO and the B response is valid from the master port.
assign slv_res_o.b_valid = mst_res_i.b_valid & (&b_sel_q);
assign slv_res_o.b_valid = mst_res_i.b_valid & b_end;

// Assign the b_channel ready output. The master port is ready if something is in the
// B FIFO. Except, if it is the last one which should do a response on the slave port.
assign mst_req_o.b_ready = (&b_sel_q) ? slv_req_i.b_ready : 1'b1;
assign mst_req_o.b_ready = b_end ? slv_req_i.b_ready : 1'b1;
// B channel error response retention FF
assign b_sel_d = sel_t'(b_sel_q + 1'b1);
assign b_resp_d = (&b_sel_q) ? axi_pkg::RESP_OKAY : (b_resp_q | mst_res_i.b.resp);
assign b_sel_d = sel_t'(b_end ? '0 : b_sel_q + 1'b1);
assign b_resp_d = b_end ? axi_pkg::RESP_OKAY : (b_resp_q | mst_res_i.b.resp);
assign b_resp_load = mst_res_i.b_valid & mst_req_o.b_ready;
`FFLARN(b_sel_q, b_sel_d, b_resp_load, '0, clk_i, rst_ni)
`FFLARN(b_resp_q, b_resp_d, b_resp_load, axi_pkg::RESP_OKAY, clk_i, rst_ni)
Expand All @@ -223,6 +293,7 @@ module axi_lite_dw_converter #(
// Input spill register of the AW channel.
axi_lite_ar_t ar_chan_spill;
logic ar_chan_spill_valid, ar_chan_spill_ready;
logic ar_progress, r_progress,

spill_register #(
.T ( axi_lite_ar_t ),
Expand All @@ -238,32 +309,77 @@ module axi_lite_dw_converter #(
.data_o ( ar_chan_spill )
);

sel_t ar_sel_q, ar_sel_d;
sel_t ar_sel_q, ar_sel_d, ar_sel_out;
logic ar_sel_load;
// AR channel output assignment
always_comb begin : proc_ar_chan_oup
mst_req_o.ar = ar_chan_spill;
mst_req_o.ar.addr = out_address(ar_chan_spill.addr, ar_sel_q);
mst_req_o.ar.addr = out_address(ar_chan_spill.addr, ar_sel_out);
end

assign ar_progress = ar_chan_spill_valid & mst_res_i.ar_ready;

if (UserAwSize) begin : gen_user_ar
// Couple AR and R FIFO
sel_t ar_sel_end, ar_sel_base;
assign ar_sel_end = UserAwSize ?
(sel_t'(1) << ar_chan_spill.user[UserArSizeLsb:+axi_pkg::SizeWidth]) >> SelOffset : '0;
assign ar_sel_base = ar_chan_spill.ar.addr[SelOffset+:SelWidth] & sel_t'(ar_sel_end -1);
assign ar_sel_out = ar_sel_q + ar_sel_base;
assign mst_req_o.aw_valid = r_progress & ar_chan_spill_valid;
assign aw_chan_spill_ready = r_progress & mst_res_i.ar_ready &
((&ar_sel_q) | (ar_sel_d == ar_sel_end));
end else begin : gen_no_user_ar
// AR and R are uncoupled
assign ar_sel_out = ar_sel_q;
assign mst_req_o.ar_valid = ar_chan_spill_valid;
assign ar_chan_spill_ready = mst_res_i.ar_ready & (&ar_sel_q);
end
// Slave port aw is valid, if there is something in the spill register.
assign mst_req_o.ar_valid = ar_chan_spill_valid;
assign ar_chan_spill_ready = mst_res_i.ar_ready & (&ar_sel_q);

assign ar_sel_load = mst_req_o.ar_valid & mst_res_i.ar_ready;
assign ar_sel_d = sel_t'(ar_sel_q + 1'b1);
assign ar_sel_d = sel_t'(ar_sel_load ? '0 : ar_sel_q + 1'b1);
`FFLARN(ar_sel_q, ar_sel_d, ar_sel_load, '0, clk_i, rst_ni)

// Responses have to be aggregated, one FF less, as the last data is feed directly through.
sel_t r_sel_q, r_sel_d;
logic r_sel_load;
axi_lite_mst_r_t [DownsizeFactor-2:0] r_chan_mst_q;
logic [DownsizeFactor-2:0] r_chan_mst_load;
logic r_end;

if (UserArSize) begin : gen_user_ar_r
// When an upstream AR completes, store the expected downstream R count
sel_t r_out;
stream_fifo #(
.FALL_THROUGH ( 1'b0 ),
.DEPTH ( UserArMaxTxns ),
.T ( sel_t ),
) i_r_count_fifo (
.clk_i,
.rst_ni,
.flush_i ( 1'b0 ),
.testmode_i ( 1'b0 ),
.usage_o ( ),
.data_i ( ar_sel_out ),
.valid_i ( mst_req_o.ar_valid & mst_resp_i.ar_ready ),
.ready_o ( r_progress ),
.data_o ( r_out ),
.valid_o ( ), // TODO: Assert true when R comes in (`r_sel_load`)
.ready_i ( r_end )
);
assign r_end = (&r_sel_q) | (r_sel_d == r_out);
end else begin : gen_no_user_ar_r
// Simply count payloads as for AW and W
assign r_end = (&r_sel_q);
assign r_progress = 1'b1;
end

for (genvar i = 0; unsigned'(i) < (DownsizeFactor-1); i++) begin : gen_r_chan_ff
assign r_chan_mst_load[i] = (sel_t'(i) == r_sel_q) & mst_res_i.r_valid & mst_req_o.r_ready;
`FFLARN(r_chan_mst_q[i], mst_res_i.r, r_chan_mst_load[i], axi_lite_mst_r_t'{default: '0}, clk_i, rst_ni)
end
assign r_sel_load = mst_res_i.r_valid & mst_req_o.r_ready;
assign r_sel_d = sel_t'(r_sel_q + 1'b1);
assign r_sel_d = sel_t'(r_sel_load ? '0 : r_sel_q + 1'b1);
`FFLARN(r_sel_q, r_sel_d, r_sel_load, '0, clk_i, rst_ni)

always_comb begin : proc_r_chan_oup
Expand All @@ -273,16 +389,16 @@ module axi_lite_dw_converter #(
};
// Response is the OR of all responses
for (int unsigned i = 0; i < (DownsizeFactor-1); i++) begin
slv_res_o.r.resp = slv_res_o.r.resp | r_chan_mst_q[i].resp;
slv_res_o.r.resp = slv_res_o.r.resp | (r_sel_q >= sel_t'(i) ? r_chan_mst_q[i].resp : '0);
slv_res_o.r.data[i*AxiMstPortDataWidth+:AxiMstPortDataWidth] = r_chan_mst_q[i].data;
end
// The highest bits of the data can be directly the master port.
slv_res_o.r.data[(DownsizeFactor-1)*AxiMstPortDataWidth+:AxiMstPortDataWidth] =
mst_res_i.r.data;
end

assign slv_res_o.r_valid = (&r_sel_q) ? mst_res_i.r_valid : 1'b0;
assign mst_req_o.r_ready = (&r_sel_q) ? slv_req_i.r_ready : 1'b1;
assign slv_res_o.r_valid = r_end ? mst_res_i.r_valid : 1'b0;
assign mst_req_o.r_ready = r_end ? slv_req_i.r_ready : 1'b1;

end else if (AxiMstPortDataWidth > AxiSlvPortDataWidth) begin : gen_upsizer
// The upsize factor determines the amount of replication.
Expand Down
23 changes: 21 additions & 2 deletions src/axi_to_axi_lite.sv
View file
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,14 @@ module axi_to_axi_lite #(
parameter int unsigned AxiUserWidth = 32'd0,
parameter int unsigned AxiMaxWriteTxns = 32'd0,
parameter int unsigned AxiMaxReadTxns = 32'd0,
parameter bit FallThrough = 1'b1, // FIFOs in Fall through mode in ID reflect
/// FIFOs in Fall through mode in ID reflect
parameter bit FallThrough = 1'b1,
/// Whether to include the lost size field on Ax user bits
parameter bit UserArSize = 1'b0,
parameter bit UserAwSize = 1'b0,
/// Least significant bit (LSB) of size in Ax user fields
parameter int unsigned UserArSizeLsb = 32'd0,
parameter int unsigned UserAwSizeLsb = 32'd0,
parameter type full_req_t = logic,
parameter type full_resp_t = logic,
parameter type lite_req_t = logic,
Expand All @@ -42,6 +49,9 @@ module axi_to_axi_lite #(
full_req_t filtered_req, splitted_req;
full_resp_t filtered_resp, splitted_resp;

// lite bus declarations
lite_req_t reflected_req;

// atomics adapter so that atomics can be resolved
axi_atop_filter #(
.AxiIdWidth ( AxiIdWidth ),
Expand Down Expand Up @@ -92,10 +102,19 @@ module axi_to_axi_lite #(
.test_i ( test_i ),
.slv_req_i ( splitted_req ),
.slv_resp_o ( splitted_resp ),
.mst_req_o ( mst_req_o ),
.mst_req_o ( reflected_req ),
.mst_resp_i ( mst_resp_i )
);

// Inject AR and AW size from full bus on user bits if requested
always_comb begin
mst_req_o = reflected_req;
if (UserArSize)
mst_req_o.ar.user[UserArSizeLsb+:axi_pkg::SizeWidth] = splitted_req.ar.size;
of (UserAwSize)
mst_req_o.aw.user[UserAwSizeLsb+:axi_pkg::SizeWidth] = splitted_req.ar.size;
end

// Assertions, check params
// pragma translate_off
`ifndef VERILATOR
Expand Down

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