diff options
Diffstat (limited to 'src/rtl/trng_csprng.v')
| -rw-r--r-- | src/rtl/trng_csprng.v | 61 |
1 files changed, 52 insertions, 9 deletions
diff --git a/src/rtl/trng_csprng.v b/src/rtl/trng_csprng.v index ce5c89c..d33e72a 100644 --- a/src/rtl/trng_csprng.v +++ b/src/rtl/trng_csprng.v @@ -49,7 +49,7 @@ module trng_csprng( output wire error, input wire discard, - input test_mode, + input wire test_mode, output wire more_seed, output wire security_error, @@ -78,6 +78,7 @@ module trng_csprng( localparam ADDR_STAT_BLOCKS_LOW = 8'h14; localparam ADDR_STAT_BLOCKS_HIGH = 8'h15; + localparam ADDR_STAT_RESEEDS = 8'h16; localparam ADDR_RND_DATA = 8'h20; @@ -103,7 +104,7 @@ module trng_csprng( localparam ADDR_TEST_SEED_W15 = 8'h8f; localparam CIPHER_KEYLEN256 = 1'b1; // 256 bit key. - localparam CIPHER_MAX_BLOCKS = 64'h1000000000000000; + localparam CIPHER_MAX_BLOCKS = 64'h0000000100000000; localparam CTRL_IDLE = 4'h0; localparam CTRL_SEED0 = 4'h1; @@ -117,7 +118,7 @@ module trng_csprng( localparam CTRL_CANCEL = 4'hf; localparam DEFAULT_NUM_ROUNDS = 5'h18; - localparam DEFAULT_NUM_BLOCKS = 64'h1000000000000000; + localparam DEFAULT_NUM_BLOCKS = 64'h0000000001000000; parameter CORE_NAME0 = 32'h63737072; // "cspr" parameter CORE_NAME1 = 32'h6e672020; // "ng " @@ -152,6 +153,12 @@ module trng_csprng( reg [63 : 0] block_stat_ctr_reg; reg [63 : 0] block_stat_ctr_new; + reg block_stat_ctr_we; + + reg [31 : 0] reseed_stat_ctr_reg; + reg [31 : 0] reseed_stat_ctr_new; + reg reseed_stat_ctr_inc; + reg reseed_stat_ctr_we; reg ready_reg; reg ready_new; @@ -279,6 +286,7 @@ module trng_csprng( cipher_block_reg <= {16{32'h00000000}}; block_ctr_reg <= {2{32'h00000000}}; block_stat_ctr_reg <= {2{32'h00000000}}; + reseed_stat_ctr_reg <= 32'h00000000; more_seed_reg <= 0; seed_ack_reg <= 0; ready_reg <= 0; @@ -313,9 +321,16 @@ module trng_csprng( if (block_ctr_we) begin block_ctr_reg <= block_ctr_new; + end + + if (block_stat_ctr_we) + begin block_stat_ctr_reg <= block_stat_ctr_new; end + if (reseed_stat_ctr_we) + reseed_stat_ctr_reg <= reseed_stat_ctr_new; + if (ready_we) ready_reg <= ready_new; @@ -421,6 +436,9 @@ module trng_csprng( ADDR_STAT_BLOCKS_HIGH: tmp_read_data = block_stat_ctr_reg[63 : 32]; + ADDR_STAT_RESEEDS: + tmp_read_data = reseed_stat_ctr_reg; + ADDR_RND_DATA: begin tmp_read_data = rnd_data; @@ -453,7 +471,7 @@ module trng_csprng( // ability to detect that maximum allowed number of blocks // has been reached. Either as defined by the application // or the hard coded CIPHER_MAX_BLOCKS value. - + // // The stat counter is a sepatate block counter updated in // sync with the block counter. It is only used to track the // number of blocks generated from the cipher as a metric @@ -465,6 +483,7 @@ module trng_csprng( block_ctr_we = 1'b0; block_ctr_max = 1'b0; block_stat_ctr_new = {2{32'h00000000}}; + block_stat_ctr_we = 1'b0; if (block_ctr_rst) begin @@ -475,8 +494,9 @@ module trng_csprng( if (block_ctr_inc) begin block_ctr_new = block_ctr_reg + 1'b1; - block_stat_ctr_new = block_stat_ctr_reg + 1'b1; block_ctr_we = 1; + block_stat_ctr_new = block_stat_ctr_reg + 1'b1; + block_stat_ctr_we = 1; end if ((block_ctr_reg == {num_blocks_high_reg, num_blocks_low_reg}) || @@ -488,6 +508,27 @@ module trng_csprng( //---------------------------------------------------------------- + // reseed_ctr + // + // A simple monotonically increasing counter that counts the + // number of times the CSPRNG has been reseeded. is reseeded. + // Note that the counter is 32-bit and it is up to SW to handle + // wrap around issues. + //---------------------------------------------------------------- + always @* + begin : reseed_ctr + reseed_stat_ctr_new = 32'h00000000; + reseed_stat_ctr_we = 0; + + if (reseed_stat_ctr_inc) + begin + reseed_stat_ctr_new = reseed_stat_ctr_reg + 1'b1; + reseed_stat_ctr_we = 1; + end + end // reseed_ctr + + + //---------------------------------------------------------------- // csprng_ctrl_fsm // // Control FSM for the CSPRNG. @@ -512,6 +553,7 @@ module trng_csprng( more_seed_new = 0; fifo_discard = 0; fifo_cipher_data_valid = 0; + reseed_stat_ctr_inc = 0; csprng_ctrl_new = CTRL_IDLE; csprng_ctrl_we = 0; @@ -597,10 +639,11 @@ module trng_csprng( end else begin - cipher_init = 1; - block_ctr_rst = 1; - csprng_ctrl_new = CTRL_INIT1; - csprng_ctrl_we = 1; + reseed_stat_ctr_inc = 1; + cipher_init = 1; + block_ctr_rst = 1; + csprng_ctrl_new = CTRL_INIT1; + csprng_ctrl_we = 1; end end |