soc/intel/cnvi: Skip calling _ON when device is already enabled

Add a check in the _ON method, similar to coreboot's ONSK handling
in its RTD3 driver, to determine whether the enable GPIO is already
asserted.

This prevents the OS from repeatedly invoking _ON, which can happen
because CNVi takes around 300ms to initialize after the GPIO is
enabled.

Change-Id: I53986aa11714666c12056460aa47396266a00a1c
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/87240
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/soc/intel/common/block/cnvi/cnvi.c b/src/soc/intel/common/block/cnvi/cnvi.c
index 1c668ba7365a..6d7bbad4e8fa 100644
--- a/src/soc/intel/common/block/cnvi/cnvi.c
+++ b/src/soc/intel/common/block/cnvi/cnvi.c
@@ -113,6 +113,9 @@ static void cnvw_fill_ssdt(const struct device *dev)
  *		Method(_ON, 0)
  *		{
  *			If (CondRefOf (\_SB.PCI0.CNVC)) {
+ *				If ((\_SB.PCI0.CNVS() == 1)) {
+ *					Return (1)
+ *				}
  *				\_SB.PCI0.CNVS(1)
  *			}
  *		}
@@ -194,6 +197,17 @@ static void cnvw_fill_ssdt(const struct device *dev)
 		{
 			acpigen_write_if_cond_ref_of("\\_SB.PCI0.CNVC");
 			{
+
+				acpigen_write_store();
+				acpigen_emit_namestring("\\_SB.PCI0.CNVS");
+				acpigen_emit_byte(LOCAL0_OP);
+
+				acpigen_write_if_lequal_op_int(LOCAL0_OP, 1);
+				{
+					acpigen_write_return_integer(1);
+				}
+				acpigen_pop_len();
+
 				acpigen_emit_namestring("\\_SB.PCI0.CNVC");
 				acpigen_emit_byte(1);
 			}