[PATCH v2 1/2][SRU][Jammy] e1000e: Enable GPT clock before sending message to CSME

[AceLan Kao]

From: Sasha Neftin <sasha.neftin at intel.com>

BugLink: https://bugs.launchpad.net/bugs/1973104

On corporate (CSME) ADL systems, the Ethernet Controller may stop working
("HW unit hang") after exiting from the s0ix state. The reason is that
CSME misses the message sent by the host. Enabling the dynamic GPT clock
solves this problem. This clock is cleared upon HW initialization.

Fixes: 3e55d231716e ("e1000e: Add handshake with the CSME to support S0ix")
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=214821
Reviewed-by: Dima Ruinskiy <dima.ruinskiy at intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin at intel.com>
Tested-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
Tested-by: Naama Meir <naamax.meir at linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen at intel.com>
(cherry picked from commit b49feacbeffc7635cc6692cbcc6a1eae2c17da6f)
Signed-off-by: Chia-Lin Kao (AceLan) <acelan.kao at canonical.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index ce48e630fe55..0fba6ccecf12 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -6499,6 +6499,10 @@ static void e1000e_s0ix_exit_flow(struct e1000_adapter *adapter)
 
 	if (er32(FWSM) & E1000_ICH_FWSM_FW_VALID &&
 	    hw->mac.type >= e1000_pch_adp) {
+		/* Keep the GPT clock enabled for CSME */
+		mac_data = er32(FEXTNVM);
+		mac_data |= BIT(3);
+		ew32(FEXTNVM, mac_data);
 		/* Request ME unconfigure the device from S0ix */
 		mac_data = er32(H2ME);
 		mac_data &= ~E1000_H2ME_START_DPG;
-- 
2.25.1