e1000e: Enable GPT clock before sending message to CSME

[ Upstream commit b49feac ]

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: 3e55d23 ("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@intel.com>
Signed-off-by: Sasha Neftin <sasha.neftin@intel.com>
Tested-by: Chia-Lin Kao (AceLan) <acelan.kao@canonical.com>
Tested-by: Naama Meir <naamax.meir@linux.intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

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;