Commit 4e29a902 authored by Guillem's avatar Guillem
Browse files

Individual quota mechanism

parent 7793b2fa
// ProjectName: LEON3_kc705_pmu
// Function : Submodule of the PMU to handle quota consumption of a single
// core.
// Description: This module checks the content of the counters selected by the
// mask register. The value of the selected counters is added and
// compared against the quota limit register. If the total quota
// is exceeded then an interrupt is risen.
// To account for a given event a 1 must be set to the Quota mask
// register. When the mask is 0 the value is not accounted for the
// quota.
// The adition of counters is sequential, therefore you could
// notice up to N cycles (where N is the number of counters
// ) from the point that the quota is exceeded until the point
// where the interrupt is risen.
// Coder : G.Cabo
// References :
`default_nettype none
`timescale 1 ns / 1 ps
`ifndef SYNT
`ifdef FORMAL
module PMU_quota #
// Width of counters registers
parameter integer REG_WIDTH = 32,
// Amount of counters
parameter integer N_COUNTERS = 9,
localparam max_width = $clog2(N_COUNTERS)+REG_WIDTH
// Global Clock Signal
input wire clk_i,
// Global Reset Signal. This Signal is Active LOW
input wire rstn_i,
// Input wire from wrapper containing the values of the counters
input wire [REG_WIDTH-1:0] counter_value_i [0:N_COUNTERS-1],
// Soft Reset Signal from configuration registeres. This Signal is
// Active HIGH
input wire softrst_i,
// Input wire from wrapper with the maximum allowed quota consumption
//Quota is calculated with the
//sum_all_counters (counter_value_i[n] * counter_quota_mask_i[n])
wire [max_width-1:0] quota_limit_i,
// Input quota interrupt mask. Only counters with their corresponding
// mask interrupt set to high can be added to compute towards the
// total quota that triggers the interrupt
input wire [N_COUNTERS-1:0] quota_mask_i,
// Interrupt quota
output wire intr_quota_o
//A quota consumption interruption is generated when the total of
//measured events exceeds the value set in quota_limit_i.
//To account for a given event a 1 must be set to the correspondent bit in
//When the mask is 0 the value is not accounted for the quota.
// Maximum width of counter to prevent overflow given the addition of N
//values of fix width
// Mask counter values that are disabled
wire [REG_WIDTH-1:0] masked_counter_value_int [0:N_COUNTERS-1];
genvar x;
//mask counter values
for (x=0; x<N_COUNTERS; x=x+1) begin : mask_counters
//when reset is eneabled the values are 0. If not reset
// check the mask and pass the value of the counter if enabled
assign masked_counter_value_int[x]=
(softrst_i || (rstn_i == 1'b0))
? {REG_WIDTH{1'b0}} : {REG_WIDTH{quota_mask_i[x]}} & counter_value_i[x];
//Add values of all the masked signals sequentially
// state_int shall jump to reset state if the mask changes
wire new_mask;
reg [N_COUNTERS-1:0] old_mask;
always_ff @(posedge clk_i, negedge rstn_i) begin
if(rstn_i == 1'b0 ) begin
old_mask <= {N_COUNTERS{1'b0}};
end else if(softrst_i) begin
old_mask <= {N_COUNTERS{1'b0}};
end else begin
old_mask <= quota_mask_i;
assign new_mask = old_mask != quota_mask_i ? 1'b1: 1'b0;
//generate a freespining counter to add values masked registers
//State 0 = Reset suma_int
//State 1 = Add counter 0 + Suman_int
// ...
//State n = Add counter n + Suman_int
//State 0 = Reset suma_int
// ...
localparam n_states = $clog2(N_COUNTERS+1);
reg [n_states-1:0] state_int;
always_ff @(posedge clk_i, negedge rstn_i) begin
integer i;
if(rstn_i == 1'b0 ) begin
state_int <={n_states{1'b0}};
end else if(softrst_i || new_mask) begin
state_int <={n_states{1'b0}};
end else begin
state_int <= state_int + 1 ;
// One state per counter + reset state -> $clog2(N_COUNTERS+1)
//TODO: I dont fully understand the difference between
//A : end else if (clk_i && !rstn_i) begin
//B : end else if (clk_i) begin
// B will throw the following spyglass error.
// [10] STARC05- AsyncResetOtherUse Warning
// ./ 90 10 Asynchronous reset signal
// 'PMU_quota.rstn_i' (flop: 'PMU_quota.old_mask[0]') used as
// non-reset/synchronous-reset at instance
// 'PMU_quota.\suma_int_reg[35] .D'
// (File Name: './' ,Line no.: '136')
localparam padding0 = max_width - REG_WIDTH;
reg [max_width-1:0] suma_int;
always_ff @(posedge clk_i, negedge rstn_i) begin
integer i;
if(rstn_i == 1'b0 ) begin
suma_int <={max_width{1'b0}};
end else if(softrst_i) begin
suma_int <={max_width{1'b0}};
end else if (clk_i && !rstn_i) begin
if(new_mask) begin
suma_int <={max_width{1'b0}};
end else begin
suma_int <= suma_int + {{padding0{1'b0}},masked_counter_value_int[state_int]};
//Check if quota is exceeded and generate interrupt
assign intr_quota_o = (suma_int > quota_limit_i )
? 1'b1 : 1'b0;
// Formal Verification section begins here.
`ifdef FORMAL
`default_nettype wire //allow compatibility with legacy code and xilinx ip
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