[dv/alert] Fix logic in cip_base_scoreboard to check alert
This PR fixes logic in cip_base_scoreboard that checks alert.
Main issue is the delay, we remove the flexibility for user to set their
own delay in alert check. We need to know the accurate predict for when
alert happens in order to know if the alert request is ignored due to
alert handshake in progress
Signed-off-by: Cindy Chen <chencindy@google.com>
diff --git a/hw/dv/sv/cip_lib/cip_base_scoreboard.sv b/hw/dv/sv/cip_lib/cip_base_scoreboard.sv
index 7aaf33e..1000021 100644
--- a/hw/dv/sv/cip_lib/cip_base_scoreboard.sv
+++ b/hw/dv/sv/cip_lib/cip_base_scoreboard.sv
@@ -24,8 +24,7 @@
bit do_alert_check = 1;
local bit under_alert_handshake[string];
local bit exp_alert[string];
- local bit is_always_on_alert[string];
- local int alert_max_delay[string];
+ local bit is_fatal_alert[string];
`uvm_component_new
@@ -132,15 +131,15 @@
endfunction
// this task is implemented to check if expected alert is triggered within certain clock cycles
- // if alert is always_on, it will expect alert handshakes until reset
- // if alert is not always_on, it will set exp_alert back to 0 once finish alert_checking
+ // if alert is fatal alert, it will expect alert handshakes until reset
+ // if alert is not fatal alert, it will set exp_alert back to 0 once finish alert_checking
virtual task check_alerts();
foreach (cfg.list_of_alerts[i]) begin
automatic string alert_name = cfg.list_of_alerts[i];
fork
forever begin
wait(exp_alert[alert_name] == 1 && cfg.under_reset == 0);
- if (is_always_on_alert[alert_name]) begin
+ if (is_fatal_alert[alert_name]) begin
while (cfg.under_reset == 0) begin
check_alert_triggered(alert_name);
wait(under_alert_handshake[alert_name] == 0 || cfg.under_reset == 1);
@@ -155,44 +154,42 @@
endtask
virtual task check_alert_triggered(string alert_name);
- repeat(alert_max_delay[alert_name]) begin
- cfg.clk_rst_vif.wait_clks(1);
- if (under_alert_handshake[alert_name] || cfg.under_reset) break;
+ // 2 clock cycles between two alert handshakes, 1 clock cycle to go back to `Idle` state,
+ // 1 clock cycle for monitor to detect alert, 1 negedge edge to make sure no race condition.
+ repeat(5) begin
+ cfg.clk_rst_vif.wait_n_clks(1);
+ if (under_alert_handshake[alert_name] || cfg.under_reset) return;
end
- if (!under_alert_handshake[alert_name] && !cfg.under_reset) begin
- `uvm_error(`gfn, $sformatf("alert %0s did not trigger within %0d cycles",
- alert_name, alert_max_delay[alert_name]))
- end
+ `uvm_error(`gfn, $sformatf("alert %0s did not trigger", alert_name))
endtask
// this function is used for individual IPs to set when they expect certain alert to trigger
// - input alert_name is the full name of the alert listed in LIST_OF_ALERTS
- // - input delay_window sets the max clock cycle delay until the actual alert triggers. This
- // number will be added an additional default delay in this function. In async mode, we will
- // add additional 6 clock cycles(the min window between two handshakes); in sync mode, 2 clock
- // cycles are added
- // - input always_on indicates once the alert is triggered, it always sends alert request to
- // alert_sender until reset is asserted
- // - output is one bit. It returns true if set_exp_alert is successful, it returns false if user
- // is trying to set alerts during alert_handshake or exp_alert is already set
- virtual function bit set_exp_alert(string alert_name, int max_delay = 0, bit always_on = 0);
+ // - input is_fatal, if set, expects to continuously trigger alert request until reset is
+ // asserted
+ // Note that this function requires user to know exact time that alert should be triggered,
+ // which means the time when `alert_req_i` is set. Because we need to accurately predict if two
+ // alerts are merged or not
+ // TODO: needs to handle a corner case where user could not predict the exact time when
+ // `alert_req_i` is set
+ virtual function void set_exp_alert(string alert_name, bit is_fatal = 0);
if (!(alert_name inside {cfg.list_of_alerts})) begin
`uvm_fatal(`gfn, $sformatf("alert_name %0s is not in cfg.list_of_alerts!", alert_name))
end
-
- if (under_alert_handshake[alert_name] || exp_alert[alert_name]) begin
- `uvm_info(`gfn, $sformatf("Current %0s alert status under_alert_handshake=%0b,\
- exp_alert=%0b, request ignored", under_alert_handshake[alert_name],
- exp_alert[alert_name], alert_name), UVM_MEDIUM)
- return 0;
- end
-
- is_always_on_alert[alert_name] = always_on;
- // in async mode, 6 clock cycles are the min window between two alert handshakes
- // in sync mode, 2 clock cycles are the min window
- alert_max_delay[alert_name] = max_delay + cfg.m_alert_agent_cfg[alert_name].is_async ? 6 : 2;
- exp_alert[alert_name] = 1;
- return 1;
+ fork
+ begin
+ // delay a negedge clk to avoid race condition between this function and
+ // `under_alert_handshake` variable
+ cfg.clk_rst_vif.wait_n_clks(1);
+ if (under_alert_handshake[alert_name] || exp_alert[alert_name]) begin
+ `uvm_info(`gfn, $sformatf("Current %0s alert status under_alert_handshake=%0b,\
+ exp_alert=%0b, request ignored", under_alert_handshake[alert_name],
+ exp_alert[alert_name], alert_name), UVM_MEDIUM)
+ end
+ is_fatal_alert[alert_name] = is_fatal;
+ exp_alert[alert_name] = 1;
+ end
+ join_none
endfunction
// task to process tl access
@@ -319,8 +316,7 @@
alert_fifos[cfg.list_of_alerts[i]].flush();
exp_alert[cfg.list_of_alerts[i]] = 0;
under_alert_handshake[cfg.list_of_alerts[i]] = 0;
- is_always_on_alert[cfg.list_of_alerts[i]] = 0;
- alert_max_delay[cfg.list_of_alerts[i]] = 0;
+ is_fatal_alert[cfg.list_of_alerts[i]] = 0;
end
endfunction
diff --git a/hw/ip/lc_ctrl/dv/env/lc_ctrl_scoreboard.sv b/hw/ip/lc_ctrl/dv/env/lc_ctrl_scoreboard.sv
index 1987cb1..d79488e 100644
--- a/hw/ip/lc_ctrl/dv/env/lc_ctrl_scoreboard.sv
+++ b/hw/ip/lc_ctrl/dv/env/lc_ctrl_scoreboard.sv
@@ -77,7 +77,7 @@
.DeviceDataWidth(OTP_PROG_DDATA_WIDTH)) item_rcv;
otp_prog_fifo.get(item_rcv);
if (cfg.lc_ctrl_vif.prog_err == 1) begin
- void'(set_exp_alert(.alert_name("fatal_prog_error"), .max_delay(0), .always_on(1)));
+ set_exp_alert(.alert_name("fatal_prog_error"), .is_fatal(1));
end
end
endtask
