ath10k: fix core PCI suspend when WoWLAN is supported but disabled

For devices where the FW supports WoWLAN but user-space has not
configured it, we don't do any PCI-specific suspend/resume operations,
because mac80211 doesn't call drv_suspend() when !wowlan. This has
particularly bad effects for some platforms, because we don't stop the
power-save timer, and if this timer goes off after the PCI controller
has suspended the link, Bad Things will happen.

Commit 32faa3f0ee50 ("ath10k: add the PCI PM core suspend/resume ops")
got some of this right, in that it understood there was a problem on
non-WoWLAN firmware. But it forgot the $subject case.

Fix this by moving all the PCI driver suspend/resume logic exclusively
into the driver PM hooks. This shouldn't affect WoWLAN support much
(this just gets executed later on).

I would just as well kill the entirety of ath10k_hif_suspend(), as it's
not even implemented on the USB or SDIO drivers. I expect that we don't
need the callback, except to return "supported" (i.e., 0) or "not
supported" (i.e., -EOPNOTSUPP).

Fixes: 32faa3f0ee50 ("ath10k: add the PCI PM core suspend/resume ops")
Fixes: 77258d409ce4 ("ath10k: enable pci soc powersaving")
Signed-off-by: Brian Norris <briannorris@chromium.org>
Cc: Ryan Hsu <ryanhsu@qti.qualcomm.com>
Cc: Kalle Valo <kvalo@qca.qualcomm.com>
Cc: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/ath10k/pci.c

@@ -2580,6 +2580,12 @@ void ath10k_pci_hif_power_down(struct ath10k *ar)
 #ifdef CONFIG_PM
 
 static int ath10k_pci_hif_suspend(struct ath10k *ar)
+{
+	/* Nothing to do; the important stuff is in the driver suspend. */
+	return 0;
+}
+
+static int ath10k_pci_suspend(struct ath10k *ar)
 {
 	/* The grace timer can still be counting down and ar->ps_awake be true.
 	 * It is known that the device may be asleep after resuming regardless
@@ -2592,6 +2598,12 @@ static int ath10k_pci_hif_suspend(struct ath10k *ar)
 }
 
 static int ath10k_pci_hif_resume(struct ath10k *ar)
+{
+	/* Nothing to do; the important stuff is in the driver resume. */
+	return 0;
+}
+
+static int ath10k_pci_resume(struct ath10k *ar)
 {
 	struct ath10k_pci *ar_pci = ath10k_pci_priv(ar);
 	struct pci_dev *pdev = ar_pci->pdev;
@@ -3403,11 +3415,7 @@ static int ath10k_pci_pm_suspend(struct device *dev)
 	struct ath10k *ar = dev_get_drvdata(dev);
 	int ret;
 
-	if (test_bit(ATH10K_FW_FEATURE_WOWLAN_SUPPORT,
-		     ar->running_fw->fw_file.fw_features))
-		return 0;
-
-	ret = ath10k_hif_suspend(ar);
+	ret = ath10k_pci_suspend(ar);
 	if (ret)
 		ath10k_warn(ar, "failed to suspend hif: %d\n", ret);
 
@@ -3419,11 +3427,7 @@ static int ath10k_pci_pm_resume(struct device *dev)
 	struct ath10k *ar = dev_get_drvdata(dev);
 	int ret;
 
-	if (test_bit(ATH10K_FW_FEATURE_WOWLAN_SUPPORT,
-		     ar->running_fw->fw_file.fw_features))
-		return 0;
-
-	ret = ath10k_hif_resume(ar);
+	ret = ath10k_pci_resume(ar);
 	if (ret)
 		ath10k_warn(ar, "failed to resume hif: %d\n", ret);