wifi: iwlwifi: mvm: fix hibernation

Fast resume is a feature that was recently introduced to speed up the
resume time. It basically keeps the firmware alive while the system
is suspended and that avoids starting again the whole device.

This flow can't work for hibernation, since when the system boots,
before the frozen image is loaded, the kernel may touch the device. As a
result, we can't assume the device is in the exact same state as before
the hibernation.

Detect that we are resuming from hibernation through the PCI device and
forbid the fast resume flow. We also need to shut down the device
cleanly when that happens.

In addition, in case the device is power gated during S3, we won't be
able to keep the device alive. Detect this situation with BE200 at least
with the help of the CSR_FUNC_SCRATCH register and reset the device upon
resume if it was power gated during S3.

Fixes: e8bb19c1d590 ("wifi: iwlwifi: support fast resume")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20240825191257.24eb3b19e74f.I3837810318dbef0a0a773cf4c4fcf89cdc6fdbd3@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 38 insertions, 3 deletions

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
index 9ad43464b702..84fd93278450 100644
--- a/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/drv.c
@@ -1577,11 +1577,12 @@ static int iwl_pci_suspend(struct device *device)
 	return 0;
 }
 
-static int iwl_pci_resume(struct device *device)
+static int _iwl_pci_resume(struct device *device, bool restore)
 {
 	struct pci_dev *pdev = to_pci_dev(device);
 	struct iwl_trans *trans = pci_get_drvdata(pdev);
 	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
+	bool device_was_powered_off = false;
 
 	/* Before you put code here, think about WoWLAN. You cannot check here
 	 * whether WoWLAN is enabled or not, and your code will run even if
@@ -1597,6 +1598,26 @@ static int iwl_pci_resume(struct device *device)
 	if (!trans->op_mode)
 		return 0;
 
+	/*
+	 * Scratch value was altered, this means the device was powered off, we
+	 * need to reset it completely.
+	 * Note: MAC (bits 0:7) will be cleared upon suspend even with wowlan,
+	 * so assume that any bits there mean that the device is usable.
+	 */
+	if (trans->trans_cfg->device_family >= IWL_DEVICE_FAMILY_BZ &&
+	    !iwl_read32(trans, CSR_FUNC_SCRATCH))
+		device_was_powered_off = true;
+
+	if (restore || device_was_powered_off) {
+		trans->state = IWL_TRANS_NO_FW;
+		/* Hope for the best here ... If one of those steps fails we
+		 * won't really know how to recover.
+		 */
+		iwl_pcie_prepare_card_hw(trans);
+		iwl_finish_nic_init(trans);
+		iwl_op_mode_device_powered_off(trans->op_mode);
+	}
+
 	/* In WOWLAN, let iwl_trans_pcie_d3_resume do the rest of the work */
 	if (test_bit(STATUS_DEVICE_ENABLED, &trans->status))
 		return 0;
@@ -1617,9 +1638,23 @@ static int iwl_pci_resume(struct device *device)
 	return 0;
 }
 
+static int iwl_pci_restore(struct device *device)
+{
+	return _iwl_pci_resume(device, true);
+}
+
+static int iwl_pci_resume(struct device *device)
+{
+	return _iwl_pci_resume(device, false);
+}
+
 static const struct dev_pm_ops iwl_dev_pm_ops = {
-	SET_SYSTEM_SLEEP_PM_OPS(iwl_pci_suspend,
-				iwl_pci_resume)
+	.suspend = pm_sleep_ptr(iwl_pci_suspend),
+	.resume = pm_sleep_ptr(iwl_pci_resume),
+	.freeze = pm_sleep_ptr(iwl_pci_suspend),
+	.thaw = pm_sleep_ptr(iwl_pci_resume),
+	.poweroff = pm_sleep_ptr(iwl_pci_suspend),
+	.restore = pm_sleep_ptr(iwl_pci_restore),
 };
 
 #define IWL_PM_OPS	(&iwl_dev_pm_ops)