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-rw-r--r--src/rtl/rosc.v14
-rw-r--r--src/rtl/rosc_entropy.v123
-rw-r--r--src/rtl/rosc_entropy_core.v155
3 files changed, 173 insertions, 119 deletions
diff --git a/src/rtl/rosc.v b/src/rtl/rosc.v
index afcc9bf..5557353 100644
--- a/src/rtl/rosc.v
+++ b/src/rtl/rosc.v
@@ -55,13 +55,7 @@ module rosc #(parameter WIDTH = 2)
// Registers.
//----------------------------------------------------------------
reg dout_reg;
-
-
- //----------------------------------------------------------------
- // Wires.
- //----------------------------------------------------------------
- reg [WIDTH : 0] sum;
- reg cin;
+ reg dout_new;
//----------------------------------------------------------------
@@ -83,7 +77,7 @@ module rosc #(parameter WIDTH = 2)
begin
if (we)
begin
- dout_reg <= cin;
+ dout_reg <= dout_new;
end
end
end
@@ -99,8 +93,12 @@ module rosc #(parameter WIDTH = 2)
//----------------------------------------------------------------
always @*
begin: adder_osc
+ reg [WIDTH : 0] sum;
+ reg cin;
+
cin = ~sum[WIDTH];
sum = opa + opb + cin;
+ dout_new = sum[WIDTH];
end
endmodule // rosc
diff --git a/src/rtl/rosc_entropy.v b/src/rtl/rosc_entropy.v
index b407f3b..32fc3d2 100644
--- a/src/rtl/rosc_entropy.v
+++ b/src/rtl/rosc_entropy.v
@@ -40,32 +40,42 @@ module rosc_entropy(
input wire clk,
input wire reset_n,
- output wire [7 : 0] debug,
- input wire debug_update,
-
input wire cs,
input wire we,
input wire [7 : 0] address,
input wire [31 : 0] write_data,
output wire [31 : 0] read_data,
- output wire error
+ output wire error,
+
+ output wire [31 : 0] entropy_data,
+ output wire entropy_valid,
+ input wire entropy_ack,
+
+ output wire [7 : 0] debug,
+ input wire debug_update,
+
+ output wire security_error
);
//----------------------------------------------------------------
// Parameters.
//----------------------------------------------------------------
- parameter ADDR_CTRL = 8'h00;
- parameter CTRL_ENABLE_BIT = 0;
+ parameter ADDR_CTRL = 8'h00;
+ parameter CTRL_ENABLE_BIT = 0;
- parameter ADDR_STATUS = 8'h01;
- parameter STATUS_RND_VALID_BIT = 0;
+ parameter ADDR_STATUS = 8'h01;
+ parameter STATUS_ENTROPY_VALID_BIT = 0;
- parameter ADDR_OPA = 8'h08;
- parameter ADDR_OPB = 8'h09;
+ parameter ADDR_OP_A = 8'h08;
+ parameter ADDR_OP_B = 8'h09;
- parameter ADDR_ENTROPY = 8'h10;
- parameter ADDR_RND = 8'h20;
+ parameter ADDR_ENTROPY = 8'h10;
+ parameter ADDR_RAW = 8'h20;
+ parameter ADDR_ROSC_OUTPUTS = 8'h21;
+
+ parameter DEFAULT_OP_A = 8'haaaaaaaa;
+ parameter DEFAULT_OP_B = ~DEFAULT_OP_A;
//----------------------------------------------------------------
@@ -87,11 +97,14 @@ module rosc_entropy(
//----------------------------------------------------------------
// Wires.
//----------------------------------------------------------------
- wire [31 : 0] entropy;
+ wire [31 : 0] raw_entropy;
+ wire [31 : 0] rosc_outputs;
+
+ wire [31 : 0] internal_entropy_data;
+ wire internal_entropy_valid;
+ wire internal_entropy_ack;
+ reg api_entropy_ack;
- wire [31 : 0] rnd_data;
- wire rnd_valid;
- reg rnd_ack;
reg [31 : 0] tmp_read_data;
reg tmp_error;
@@ -100,8 +113,13 @@ module rosc_entropy(
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
- assign read_data = tmp_read_data;
- assign error = tmp_error;
+ assign read_data = tmp_read_data;
+ assign error = tmp_error;
+ assign security_error = 0;
+
+ assign internal_entropy_ack = api_entropy_ack | entropy_ack;
+ assign entropy_data = internal_entropy_data;
+ assign entropy_data_valid = internal_entropy_valid;
//----------------------------------------------------------------
@@ -111,16 +129,17 @@ module rosc_entropy(
.clk(clk),
.reset_n(reset_n),
- .enable(en_reg),
+ .en(en_reg),
.opa(op_a_reg),
.opb(op_b_reg),
- .entropy(entropy),
+ .raw_entropy(raw_entropy),
+ .rosc_outputs(rosc_outputs),
- .rnd_data(rnd_data),
- .rnd_valid(rnd_valid),
- .rnd_ack(rnd_ack),
+ .entropy_data(internal_entropy_data),
+ .entropy_valid(internal_entropy_valid),
+ .entropy_ack(internal_entropy_ack),
.debug(debug),
.debug_update(debug_update)
@@ -139,8 +158,8 @@ module rosc_entropy(
if (!reset_n)
begin
en_reg <= 1;
- op_a_reg <= 32'h01010101;
- op_a_reg <= 32'h10101010;
+ op_a_reg <= DEFAULT_OP_A;
+ op_b_reg <= DEFAULT_OP_B;
end
else
begin
@@ -158,7 +177,6 @@ module rosc_entropy(
begin
op_b_reg <= op_b_new;
end
-
end
end // reg_update
@@ -171,15 +189,15 @@ module rosc_entropy(
//----------------------------------------------------------------
always @*
begin : api_logic
- en_new = 0;
- en_we = 0;
- op_a_new = 0;
- op_a_we = 0;
- op_b_new = 0;
- op_b_we = 0;
- rnd_ack = 0;
- tmp_read_data = 32'h00000000;
- tmp_error = 0;
+ en_new = 0;
+ en_we = 0;
+ op_a_new = 0;
+ op_a_we = 0;
+ op_b_new = 0;
+ op_b_we = 0;
+ api_entropy_ack = 0;
+ tmp_read_data = 32'h00000000;
+ tmp_error = 0;
if (cs)
begin
@@ -193,13 +211,13 @@ module rosc_entropy(
en_we = 1;
end
- ADDR_OPA:
+ ADDR_OP_A:
begin
op_a_new = write_data;
op_a_we = 1;
end
- ADDR_OPB:
+ ADDR_OP_B:
begin
op_b_new = write_data;
op_b_we = 1;
@@ -221,28 +239,33 @@ module rosc_entropy(
ADDR_STATUS:
begin
- tmp_read_data[STATUS_RND_VALID_BIT] = rnd_valid;
+ tmp_read_data[STATUS_ENTROPY_VALID_BIT] = entropy_valid;
end
- ADDR_OPA:
- begin
- tmp_read_data = op_a_reg;
- end
+ ADDR_OP_A:
+ begin
+ tmp_read_data = op_a_reg;
+ end
- ADDR_OPB:
- begin
- tmp_read_data = op_b_reg;
- end
+ ADDR_OP_B:
+ begin
+ tmp_read_data = op_b_reg;
+ end
ADDR_ENTROPY:
begin
- tmp_read_data = entropy;
+ tmp_read_data = entropy_data;
+ api_entropy_ack = 1;
+ end
+
+ ADDR_RAW:
+ begin
+ tmp_read_data = raw_entropy;
end
- ADDR_RND:
+ ADDR_ROSC_OUTPUTS:
begin
- tmp_read_data = rnd_data;
- rnd_ack = 1;
+ tmp_read_data = rosc_outputs;
end
default:
diff --git a/src/rtl/rosc_entropy_core.v b/src/rtl/rosc_entropy_core.v
index 5b4b8c4..98e08e6 100644
--- a/src/rtl/rosc_entropy_core.v
+++ b/src/rtl/rosc_entropy_core.v
@@ -40,16 +40,17 @@ module rosc_entropy_core(
input wire clk,
input wire reset_n,
- input wire enable,
+ input wire en,
input wire [31 : 0] opa,
input wire [31 : 0] opb,
- output [31 : 0] entropy,
+ output wire [31 : 0] raw_entropy,
+ output wire [31 : 0] rosc_outputs,
- output wire [31 : 0] rnd_data,
- output wire rnd_valid,
- input wire rnd_ack,
+ output wire [31 : 0] entropy_data,
+ output wire entropy_valid,
+ input wire entropy_ack,
output wire [7 : 0] debug,
input wire debug_update
@@ -59,6 +60,7 @@ module rosc_entropy_core(
//----------------------------------------------------------------
// Parameters.
//----------------------------------------------------------------
+ parameter DEBUG_DELAY = 32'h002c4b40;
parameter NUM_SHIFT_BITS = 8'h20;
parameter SAMPLE_CLK_CYCLES = 8'hff;
@@ -68,16 +70,14 @@ module rosc_entropy_core(
//----------------------------------------------------------------
reg [31 : 0] ent_shift_reg;
reg [31 : 0] ent_shift_new;
+ reg ent_shift_we;
- reg ent_shift_we_reg;
- reg ent_shift_we_new;
+ reg [31 : 0] entropy_reg;
+ reg entropy_we;
- reg [31 : 0] rnd_reg;
- reg rnd_we;
-
- reg rnd_valid_reg;
- reg rnd_valid_new;
- reg rnd_valid_we;
+ reg entropy_valid_reg;
+ reg entropy_valid_new;
+ reg entropy_valid_we;
reg bit_we_reg;
reg bit_we_new;
@@ -90,7 +90,13 @@ module rosc_entropy_core(
reg [7 : 0] sample_ctr_reg;
reg [7 : 0] sample_ctr_new;
+ reg [31 : 0] debug_delay_ctr_reg;
+ reg [31 : 0] debug_delay_ctr_new;
+ reg debug_delay_ctr_we;
+
reg [7 : 0] debug_reg;
+ reg debug_we;
+
reg debug_update_reg;
@@ -104,10 +110,11 @@ module rosc_entropy_core(
//----------------------------------------------------------------
// Concurrent connectivity for ports etc.
//----------------------------------------------------------------
- assign entropy = ent_shift_reg;
- assign rnd_data = rnd_reg;
- assign rnd_valid = rnd_valid_reg;
- assign debug = debug_reg;
+ assign rosc_outputs = rosc_dout;
+ assign raw_entropy = ent_shift_reg;
+ assign entropy_data = entropy_reg;
+ assign entropy_valid = entropy_valid_reg;
+ assign debug = debug_reg;
//----------------------------------------------------------------
@@ -142,22 +149,21 @@ module rosc_entropy_core(
begin
if (!reset_n)
begin
- ent_shift_reg <= 32'h00000000;
- ent_shift_we_reg <= 0;
- rnd_reg <= 32'h00000000;
- rnd_valid_reg <= 0;
- bit_ctr_reg <= 8'h00;
- sample_ctr_reg <= 8'h00;
- debug_reg <= 8'h00;
- debug_update_reg <= 0;
+ ent_shift_reg <= 32'h00000000;
+ entropy_reg <= 32'h00000000;
+ entropy_valid_reg <= 0;
+ bit_ctr_reg <= 8'h00;
+ sample_ctr_reg <= 8'h00;
+ debug_delay_ctr_reg <= 32'h00000000;
+ debug_reg <= 8'h00;
+ debug_update_reg <= 0;
end
else
begin
sample_ctr_reg <= sample_ctr_new;
- ent_shift_we_reg <= ent_shift_we_new;
debug_update_reg <= debug_update;
- if (ent_shift_we_reg)
+ if (ent_shift_we)
begin
ent_shift_reg <= ent_shift_new;
end
@@ -167,38 +173,69 @@ module rosc_entropy_core(
bit_ctr_reg <= bit_ctr_new;
end
- if (rnd_we)
+ if (entropy_we)
+ begin
+ entropy_reg <= ent_shift_reg;
+ end
+
+ if (entropy_valid_we)
begin
- rnd_reg <= ent_shift_reg;
+ entropy_valid_reg <= entropy_valid_new;
end
- if (rnd_valid_we)
+ if (debug_delay_ctr_we)
begin
- rnd_valid_reg <= rnd_valid_new;
+ debug_delay_ctr_reg <= debug_delay_ctr_new;
end
- if (debug_update_reg)
+ if (debug_we)
begin
- debug_reg <= rnd_reg[7 : 0];
+ debug_reg <= ent_shift_reg[7 : 0];
end
end
end // reg_update
//----------------------------------------------------------------
- // rnd_out
+ // debug_out
+ //
+ // Logic that updates the debug port.
+ //----------------------------------------------------------------
+ always @*
+ begin : debug_out
+ debug_delay_ctr_new = 8'h00000000;
+ debug_delay_ctr_we = 0;
+ debug_we = 0;
+
+ if (debug_update_reg)
+ begin
+ debug_delay_ctr_new = debug_delay_ctr_reg + 1'b1;
+ debug_delay_ctr_we = 1;
+ end
+
+ if (debug_delay_ctr_reg == DEBUG_DELAY)
+ begin
+ debug_delay_ctr_new = 8'h00000000;
+ debug_delay_ctr_we = 1;
+ debug_we = 1;
+ end
+ end
+
+
+ //----------------------------------------------------------------
+ // entropy_out
//
// Logic that implements the random output control. If we have
- // added more than NUM_SHIFT_BITS we raise the rnd_valid flag.
+ // added more than NUM_SHIFT_BITS we raise the entropy_valid flag.
// When we detect and ACK, the valid flag is dropped.
//----------------------------------------------------------------
always @*
- begin : rnd_out
- bit_ctr_new = 8'h00;
- bit_ctr_we = 0;
- rnd_we = 0;
- rnd_valid_new = 0;
- rnd_valid_we = 0;
+ begin : entropy_out
+ bit_ctr_new = 8'h00;
+ bit_ctr_we = 0;
+ entropy_we = 0;
+ entropy_valid_new = 0;
+ entropy_valid_we = 0;
if (bit_ctr_inc)
begin
@@ -210,52 +247,48 @@ module rosc_entropy_core(
end
else
begin
- rnd_we = 1;
- rnd_valid_new = 1;
- rnd_valid_we = 1;
+ entropy_we = 1;
+ entropy_valid_new = 1;
+ entropy_valid_we = 1;
end
end
- if (rnd_ack)
+ if (entropy_ack)
begin
- bit_ctr_new = 8'h00;
- bit_ctr_we = 1;
- rnd_valid_new = 0;
- rnd_valid_we = 1;
+ bit_ctr_new = 8'h00;
+ bit_ctr_we = 1;
+ entropy_valid_new = 0;
+ entropy_valid_we = 1;
end
end
//----------------------------------------------------------------
- // rnd_gen
+ // entropy_gen
//
- // Logic that implements the actual random bit value generator
+ // Logic that implements the actual entropy bit value generator
// by XOR mixing the oscillator outputs. These outputs are
// sampled once every SAMPLE_CLK_CYCLES.
- //
- // Note that the update of the shift register is delayed
- // one cycle to allow the outputs from the oscillators
- // to be updated.
//----------------------------------------------------------------
always @*
- begin : rnd_gen
+ begin : entropy_gen
reg ent_bit;
- bit_ctr_inc = 0;
- rosc_we = 0;
- ent_shift_we_new = 0;
+ bit_ctr_inc = 0;
+ rosc_we = 0;
+ ent_shift_we = 0;
ent_bit = ^rosc_dout;
ent_shift_new = {ent_shift_reg[30 : 0], ent_bit};
sample_ctr_new = sample_ctr_reg + 1'b1;
- if (enable && (sample_ctr_reg == SAMPLE_CLK_CYCLES))
+ if (en && (sample_ctr_reg == SAMPLE_CLK_CYCLES))
begin
sample_ctr_new = 8'h00;
bit_ctr_inc = 1;
rosc_we = 1;
- ent_shift_we_new = 1;
+ ent_shift_we = 1;
end
end
endmodule // rosc_entropy_core
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