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Partially solved fpga boot.

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Ross Thompson 2023-07-05 17:30:55 -05:00
parent 4b3b590f21
commit c0fdd3fbca
1 changed files with 44 additions and 38 deletions
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82
src/uncore/plic_apb.sv
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@ -31,7 +31,6 @@
// and limitations under the License.
////////////////////////////////////////////////////////////////////////////////////////////////
`define N P.PLIC_NUM_SRC
// number of interrupt sources
// does not include source 0, which does not connect to anything according to spec
// up to 63 sources supported; in the future, allow up to 1023 sources
@ -59,19 +58,20 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
logic [31:0] Din, Dout;
// context-independent signals
logic [`N:1] requests;
logic [`N:1][2:0] intPriority;
logic [`N:1] intInProgress, intPending, nextIntPending;
logic [P.PLIC_NUM_SRC:1] requests;
logic [P.PLIC_NUM_SRC:1][2:0] intPriority;
logic [P.PLIC_NUM_SRC:1] intInProgress, intPending, nextIntPending;
// context-dependent signals
logic [`C-1:0][2:0] intThreshold;
logic [`C-1:0][`N:1] intEn;
logic [`C-1:0][P.PLIC_NUM_SRC:1] intEn;
logic [`C-1:0][5:0] intClaim; // ID's are 6 bits if we stay within 63 sources
logic [`C-1:0][7:1][`N:1] irqMatrix;
logic [`C-1:0][7:1][P.PLIC_NUM_SRC:1] irqMatrix;
logic [`C-1:0][7:1] priorities_with_irqs;
logic [`C-1:0][7:1] max_priority_with_irqs;
logic [`C-1:0][`N:1] irqs_at_max_priority;
logic [`C-1:0][P.PLIC_NUM_SRC:1] irqs_at_max_priority;
logic [`C-1:0][7:1] threshMask;
logic [P.PLIC_NUM_SRC-1:0] One;
// =======
// AHB I/O
@ -81,6 +81,7 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
assign memread = ~PWRITE & PSEL; // read at start of access phase. PENABLE hasn't set up before this
assign PREADY = 1'b1; // PLIC never takes >1 cycle to respond
assign entry = {PADDR[23:2],2'b0};
assign One[P.PLIC_NUM_SRC-1:1] = '0; assign One[0] = 1'b1; // Vivado does not like this as a single assignment.
// account for subword read/write circuitry
// -- Note PLIC registers are 32 bits no matter what; access them with LW SW.
@ -92,7 +93,12 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
assign Din = PWDATA[31:0];
end
if (P.PLIC_NUM_SRC_LT_32) `define PLIC_NUM_SRC_LT_32
// *** RT: 05 July 2023: BUG BUG BUG. PLIC_NUM_SRC_LT_32 is undefined after parameterization
// the FPGA does work the following code. For now I'm leaving the `define undefined but this
// means the code is only valid for 33 to 64 interrupt sources. In general this needs to be
// rethought for a more generalized implementation.
//if (P.PLIC_NUM_SRC_LT_32) `define PLIC_NUM_SRC_LT_32
//`define PLIC_NUM_SRC_LT_32
// ==================
// Register Interface
@ -101,29 +107,29 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
always @(posedge PCLK) begin
// resetting
if (~PRESETn) begin
intPriority <= #1 {`N{3'b0}};
intEn <= #1 {2*`N{1'b0}};
intThreshold <= #1 {2{3'b0}};
intInProgress <= #1 {`N{1'b0}};
intPriority <= #1 '0;
intEn <= #1 '0;
intThreshold <= #1 '0;
intInProgress <= #1 '0;
// writing
end else begin
if (memwrite)
casez(entry)
24'h0000??: intPriority[entry[7:2]] <= #1 Din[2:0];
`ifdef PLIC_NUM_SRC_LT_32 // eventually switch to a generate for loop so as to deprecate PLIC_NUM_SRC_LT_32 and allow up to 1023 sources
24'h002000: intEn[0][`N:1] <= #1 Din[`N:1];
24'h002080: intEn[1][`N:1] <= #1 Din[`N:1];
24'h002000: intEn[0][P.PLIC_NUM_SRC:1] <= #1 Din[P.PLIC_NUM_SRC:1];
24'h002080: intEn[1][P.PLIC_NUM_SRC:1] <= #1 Din[P.PLIC_NUM_SRC:1];
`endif
`ifndef PLIC_NUM_SRC_LT_32
24'h002000: intEn[0][31:1] <= #1 Din[31:1];
24'h002004: intEn[0][`N:32] <= #1 Din[31:0];
24'h002004: intEn[0][P.PLIC_NUM_SRC:32] <= #1 Din[P.PLIC_NUM_SRC-32:0];
24'h002080: intEn[1][31:1] <= #1 Din[31:1];
24'h002084: intEn[1][`N:32] <= #1 Din[31:0];
24'h002084: intEn[1][P.PLIC_NUM_SRC:32] <= #1 Din[P.PLIC_NUM_SRC-32:0];
`endif
24'h200000: intThreshold[0] <= #1 Din[2:0];
24'h200004: intInProgress <= #1 intInProgress & ~({{`N-1{1'b0}}, 1'b1} << (Din[5:0]-1)); // lower "InProgress" to signify completion
24'h200004: intInProgress <= #1 intInProgress & ~(One << (Din[5:0]-1)); // lower "InProgress" to signify completion
24'h201000: intThreshold[1] <= #1 Din[2:0];
24'h201004: intInProgress <= #1 intInProgress & ~({{`N-1{1'b0}}, 1'b1} << (Din[5:0]-1)); // lower "InProgress" to signify completion
24'h201004: intInProgress <= #1 intInProgress & ~(One << (Din[5:0]-1)); // lower "InProgress" to signify completion
endcase
// Read synchronously because a read can have side effect of changing intInProgress
if (memread) begin
@ -131,27 +137,27 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
24'h000000: Dout <= #1 32'b0; // there is no intPriority[0]
24'h0000??: Dout <= #1 {29'b0,intPriority[entry[7:2]]};
`ifdef PLIC_NUM_SRC_LT_32
24'h001000: Dout <= #1 {{(31-`N){1'b0}},intPending,1'b0};
24'h002000: Dout <= #1 {{(31-`N){1'b0}},intEn[0],1'b0};
24'h002080: Dout <= #1 {{(31-`N){1'b0}},intEn[1],1'b0};
24'h001000: Dout <= #1 {{(31-P.PLIC_NUM_SRC){1'b0}},intPending,1'b0};
24'h002000: Dout <= #1 {{(31-P.PLIC_NUM_SRC){1'b0}},intEn[0],1'b0};
24'h002080: Dout <= #1 {{(31-P.PLIC_NUM_SRC){1'b0}},intEn[1],1'b0};
`endif
`ifndef PLIC_NUM_SRC_LT_32
24'h001000: Dout <= #1 {intPending[31:1],1'b0};
24'h001004: Dout <= #1 {{(63-`N){1'b0}},intPending[`N:32]};
24'h001004: Dout <= #1 {{(63-P.PLIC_NUM_SRC){1'b0}},intPending[P.PLIC_NUM_SRC:32]};
24'h002000: Dout <= #1 {intEn[0][31:1],1'b0};
24'h002004: Dout <= #1 {{(63-`N){1'b0}},intEn[0][`N:32]};
24'h002004: Dout <= #1 {{(63-P.PLIC_NUM_SRC){1'b0}},intEn[0][P.PLIC_NUM_SRC:32]};
24'h002080: Dout <= #1 {intEn[0][31:1],1'b0};
24'h002084: Dout <= #1 {{(63-`N){1'b0}},intEn[1][`N:32]};
24'h002084: Dout <= #1 {{(63-P.PLIC_NUM_SRC){1'b0}},intEn[1][P.PLIC_NUM_SRC:32]};
`endif
24'h200000: Dout <= #1 {29'b0,intThreshold[0]};
24'h200004: begin
Dout <= #1 {26'b0,intClaim[0]};
intInProgress <= #1 intInProgress | ({{`N-1{1'b0}}, 1'b1} << (intClaim[0]-1)); // claimed requests are currently in progress of being serviced until they are completed
intInProgress <= #1 intInProgress | (One << (intClaim[0]-1)); // claimed requests are currently in progress of being serviced until they are completed
end
24'h201000: Dout <= #1 {29'b0,intThreshold[1]};
24'h201004: begin
Dout <= #1 {26'b0,intClaim[1]};
intInProgress <= #1 intInProgress | ({{`N-1{1'b0}}, 1'b1} << (intClaim[1]-1)); // claimed requests are currently in progress of being serviced until they are completed
intInProgress <= #1 intInProgress | (One << (intClaim[1]-1)); // claimed requests are currently in progress of being serviced until they are completed
end
default: Dout <= #1 32'h0; // invalid access
endcase
@ -161,14 +167,14 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
// connect sources to requests
always_comb begin
requests = {`N{1'b0}};
requests = {P.PLIC_NUM_SRC{1'b0}};
if(P.PLIC_GPIO_ID != 0) requests[P.PLIC_GPIO_ID] = GPIOIntr;
if(P.PLIC_UART_ID != 0) requests[P.PLIC_UART_ID] = UARTIntr;
end
// pending interrupt request
assign nextIntPending = (intPending | requests) & ~intInProgress;
flopr #(`N) intPendingFlop(PCLK,~PRESETn,nextIntPending,intPending);
flopr #(P.PLIC_NUM_SRC) intPendingFlop(PCLK,~PRESETn,nextIntPending,intPending);
// context-dependent signals
genvar ctx;
@ -181,7 +187,7 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
// ("active" meaning it is enabled in context <ctx> and is pending)
genvar src, pri;
for (pri=1; pri<=7; pri++) begin
for (src=1; src<=`N; src++) begin
for (src=1; src<=P.PLIC_NUM_SRC; src++) begin
assign irqMatrix[ctx][pri][src] = (intPriority[src]==pri) & intPending[src] & intEn[ctx][src];
end
end
@ -210,14 +216,14 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
// of the sources at the highest priority level that has active requests,
// which sources have active requests?
assign irqs_at_max_priority[ctx][`N:1] =
({`N{max_priority_with_irqs[ctx][7]}} & irqMatrix[ctx][7]) |
({`N{max_priority_with_irqs[ctx][6]}} & irqMatrix[ctx][6]) |
({`N{max_priority_with_irqs[ctx][5]}} & irqMatrix[ctx][5]) |
({`N{max_priority_with_irqs[ctx][4]}} & irqMatrix[ctx][4]) |
({`N{max_priority_with_irqs[ctx][3]}} & irqMatrix[ctx][3]) |
({`N{max_priority_with_irqs[ctx][2]}} & irqMatrix[ctx][2]) |
({`N{max_priority_with_irqs[ctx][1]}} & irqMatrix[ctx][1]);
assign irqs_at_max_priority[ctx][P.PLIC_NUM_SRC:1] =
({P.PLIC_NUM_SRC{max_priority_with_irqs[ctx][7]}} & irqMatrix[ctx][7]) |
({P.PLIC_NUM_SRC{max_priority_with_irqs[ctx][6]}} & irqMatrix[ctx][6]) |
({P.PLIC_NUM_SRC{max_priority_with_irqs[ctx][5]}} & irqMatrix[ctx][5]) |
({P.PLIC_NUM_SRC{max_priority_with_irqs[ctx][4]}} & irqMatrix[ctx][4]) |
({P.PLIC_NUM_SRC{max_priority_with_irqs[ctx][3]}} & irqMatrix[ctx][3]) |
({P.PLIC_NUM_SRC{max_priority_with_irqs[ctx][2]}} & irqMatrix[ctx][2]) |
({P.PLIC_NUM_SRC{max_priority_with_irqs[ctx][1]}} & irqMatrix[ctx][1]);
// of the sources at the highest priority level that has active requests,
// choose the source with the lowest source ID to be the most urgent
@ -225,7 +231,7 @@ module plic_apb import cvw::*; #(parameter cvw_t P) (
integer k;
always_comb begin
intClaim[ctx] = 6'b0;
for (k=`N; k>0; k--) begin
for (k=P.PLIC_NUM_SRC; k>0; k--) begin
if (irqs_at_max_priority[ctx][k]) intClaim[ctx] = k[5:0];
end
end