[dv] pins_if improvement
pins_if enables a default pullup or pulldown with Pull strength.
This commit parameterizes pins_if to pick between Pull and Weak
strengths.
Signed-off-by: Srikrishna Iyer <sriyer@google.com>
diff --git a/hw/dv/sv/common_ifs/common_ifs.core b/hw/dv/sv/common_ifs/common_ifs.core
index 31ca693..369a0d3 100644
--- a/hw/dv/sv/common_ifs/common_ifs.core
+++ b/hw/dv/sv/common_ifs/common_ifs.core
@@ -8,6 +8,7 @@
filesets:
files_dv:
depend:
+ - lowrisc:prim:assert
- lowrisc:dv:pins_if
files:
- clk_if.sv
diff --git a/hw/dv/sv/common_ifs/pins_if.sv b/hw/dv/sv/common_ifs/pins_if.sv
index b387b20..4bbc4bb 100644
--- a/hw/dv/sv/common_ifs/pins_if.sv
+++ b/hw/dv/sv/common_ifs/pins_if.sv
@@ -8,11 +8,15 @@
`ifndef SYNTHESIS
interface pins_if #(
- parameter int Width = 1
+ parameter int Width = 1,
+ parameter bit [8*4-1:0] PullStrength = "Pull"
) (
inout [Width-1:0] pins
);
+ `include "prim_assert.sv"
+
+ `ASSERT_INIT(PullStrengthParamValid, PullStrength inside {"Weak", "Pull"})
logic [Width-1:0] pins_o; // value to be driven out
bit [Width-1:0] pins_oe = '0; // output enable
@@ -78,10 +82,18 @@
pins_pu[i] ? 1'b1 :
pins_pd[i] ? 1'b0 : 1'bz;
`else
- // Drive the pin with pull strength based on whether pullup / pulldown is enabled.
- assign (pull0, pull1) pins[i] = ~pins_oe[i] ? (pins_pu[i] ? 1'b1 :
- pins_pd[i] ? 1'b0 : 1'bz) : 1'bz;
-
+ // Drive the pin based on whether pullup / pulldown is enabled.
+ //
+ // If output is not enabled, then the pin is pulled up or down with the `PullStrength` strength
+ // Pullup has priority over pulldown.
+ if (PullStrength == "Pull") begin : gen_pull_strength_pull
+ assign (pull0, pull1) pins[i] = ~pins_oe[i] ? (pins_pu[i] ? 1'b1 :
+ pins_pd[i] ? 1'b0 : 1'bz) : 1'bz;
+ end : gen_pull_strength_pull
+ else if (PullStrength == "Weak") begin : gen_pull_strength_weak
+ assign (weak0, weak1) pins[i] = ~pins_oe[i] ? (pins_pu[i] ? 1'b1 :
+ pins_pd[i] ? 1'b0 : 1'bz) : 1'bz;
+ end : gen_pull_strength_weak
// If output enable is 1, strong driver assigns pin to 'value to be driven out';
// the external strong driver can still affect pin, if exists.
