[Intel-wired-lan] [PATCH net-queue v2] igc: Fix suspending when PTM is active

[Vinicius Costa Gomes <vinicius.gomes@intel.com>]

Some mainboard/CPU combinations, in particular, Alder Lake-S with a
W680 mainboard, have shown problems (system hangs usually, no kernel
logs) with suspend/resume when PCIe PTM is enabled and active. In some
cases, it could be reproduced when removing the igc module.

The best we can do is to stop PTM dialogs from the downstream/device
side before the interface is brought down. PCIe PTM will be re-enabled
when the interface is being brought up.

Fixes: a90ec8483732 ("igc: Add support for PTP getcrosststamp()")
Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
Acked-by: Paul Menzel <pmenzel@molgen.mpg.de>
---
 drivers/net/ethernet/intel/igc/igc_ptp.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c b/drivers/net/ethernet/intel/igc/igc_ptp.c
index 0d6e3215e98f..653e9f1e35b5 100644
--- a/drivers/net/ethernet/intel/igc/igc_ptp.c
+++ b/drivers/net/ethernet/intel/igc/igc_ptp.c
@@ -992,6 +992,17 @@ static void igc_ptp_time_restore(struct igc_adapter *adapter)
 	igc_ptp_write_i225(adapter, &ts);
 }
 
+static void igc_ptm_stop(struct igc_adapter *adapter)
+{
+	struct igc_hw *hw = &adapter->hw;
+	u32 ctrl;
+
+	ctrl = rd32(IGC_PTM_CTRL);
+	ctrl &= ~IGC_PTM_CTRL_EN;
+
+	wr32(IGC_PTM_CTRL, ctrl);
+}
+
 /**
  * igc_ptp_suspend - Disable PTP work items and prepare for suspend
  * @adapter: Board private structure
@@ -1009,8 +1020,10 @@ void igc_ptp_suspend(struct igc_adapter *adapter)
 	adapter->ptp_tx_skb = NULL;
 	clear_bit_unlock(__IGC_PTP_TX_IN_PROGRESS, &adapter->state);
 
-	if (pci_device_is_present(adapter->pdev))
+	if (pci_device_is_present(adapter->pdev)) {
 		igc_ptp_time_save(adapter);
+		igc_ptm_stop(adapter);
+	}
 }
 
 /**
-- 
2.35.1