iwlwifi: pcie: add pm_prepare and pm_complete ops

With these ops, we can know when we are about to enter system suspend.
This allows us to exit D0i3 state before entering suspend.
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

drivers/net/wireless/intel/iwlwifi/iwl-trans.h

@@ -836,6 +836,7 @@ struct iwl_trans {
 
 	enum iwl_plat_pm_mode system_pm_mode;
 	enum iwl_plat_pm_mode runtime_pm_mode;
+	bool suspending;
 
 	/* pointer to trans specific struct */
 	/*Ensure that this pointer will always be aligned to sizeof pointer */

drivers/net/wireless/intel/iwlwifi/pcie/drv.c

@@ -811,6 +811,45 @@ static int iwl_pci_runtime_resume(struct device *device)
 
 	return 0;
 }
+
+static int iwl_pci_system_prepare(struct device *device)
+{
+	struct pci_dev *pdev = to_pci_dev(device);
+	struct iwl_trans *trans = pci_get_drvdata(pdev);
+
+	IWL_DEBUG_RPM(trans, "preparing for system suspend\n");
+
+	/* This is called before entering system suspend and before
+	 * the runtime resume is called.  Set the suspending flag to
+	 * prevent the wakelock from being taken.
+	 */
+	trans->suspending = true;
+
+	/* Wake the device up from runtime suspend before going to
+	 * platform suspend.  This is needed because we don't know
+	 * whether wowlan any is set and, if it's not, mac80211 will
+	 * disconnect (in which case, we can't be in D0i3).
+	 */
+	pm_runtime_resume(device);
+
+	return 0;
+}
+
+static void iwl_pci_system_complete(struct device *device)
+{
+	struct pci_dev *pdev = to_pci_dev(device);
+	struct iwl_trans *trans = pci_get_drvdata(pdev);
+
+	IWL_DEBUG_RPM(trans, "completing system suspend\n");
+
+	/* This is called as a counterpart to the prepare op.  It is
+	 * called either when suspending fails or when suspend
+	 * completed successfully.  Now there's no risk of grabbing
+	 * the wakelock anymore, so we can release the suspending
+	 * flag.
+	 */
+	trans->suspending = false;
+}
 #endif /* CONFIG_IWLWIFI_PCIE_RTPM */
 
 static const struct dev_pm_ops iwl_dev_pm_ops = {
@@ -820,6 +859,8 @@ static const struct dev_pm_ops iwl_dev_pm_ops = {
 	SET_RUNTIME_PM_OPS(iwl_pci_runtime_suspend,
 			   iwl_pci_runtime_resume,
 			   NULL)
+	.prepare = iwl_pci_system_prepare,
+	.complete = iwl_pci_system_complete,
 #endif /* CONFIG_IWLWIFI_PCIE_RTPM */
 };