ath9k: improve suspend/resume reliability

Ensure that drv_start() always returns true, as a failing hw start usually
eventually leads to crashes when there's still a station entry present.
Call a power-on reset after a resume and after a hw reset failure to bring
the hardware back to life again.
Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/hw.c

@@ -1450,9 +1450,14 @@ static bool ath9k_hw_set_reset_reg(struct ath_hw *ah, u32 type)
 	REG_WRITE(ah, AR_RTC_FORCE_WAKE,
 		  AR_RTC_FORCE_WAKE_EN | AR_RTC_FORCE_WAKE_ON_INT);
 
+	if (!ah->reset_power_on)
+		type = ATH9K_RESET_POWER_ON;
+
 	switch (type) {
 	case ATH9K_RESET_POWER_ON:
 		ret = ath9k_hw_set_reset_power_on(ah);
+		if (!ret)
+			ah->reset_power_on = true;
 		break;
 	case ATH9K_RESET_WARM:
 	case ATH9K_RESET_COLD:

drivers/net/wireless/ath/ath9k/hw.h

@@ -741,6 +741,7 @@ struct ath_hw {
 	u32 rfkill_polarity;
 	u32 ah_flags;
 
+	bool reset_power_on;
 	bool htc_reset_init;
 
 	enum nl80211_iftype opmode;

drivers/net/wireless/ath/ath9k/main.c

@@ -639,8 +639,7 @@ static int ath9k_start(struct ieee80211_hw *hw)
 		ath_err(common,
 			"Unable to reset hardware; reset status %d (freq %u MHz)\n",
 			r, curchan->center_freq);
-		spin_unlock_bh(&sc->sc_pcu_lock);
-		goto mutex_unlock;
+		ah->reset_power_on = false;
 	}
 
 	/* Setup our intr mask. */
@@ -665,11 +664,8 @@ static int ath9k_start(struct ieee80211_hw *hw)
 	clear_bit(SC_OP_INVALID, &sc->sc_flags);
 	sc->sc_ah->is_monitoring = false;
 
-	if (!ath_complete_reset(sc, false)) {
-		r = -EIO;
-		spin_unlock_bh(&sc->sc_pcu_lock);
-		goto mutex_unlock;
-	}
+	if (!ath_complete_reset(sc, false))
+		ah->reset_power_on = false;
 
 	if (ah->led_pin >= 0) {
 		ath9k_hw_cfg_output(ah, ah->led_pin,
@@ -688,12 +684,11 @@ static int ath9k_start(struct ieee80211_hw *hw)
 	if (ah->caps.pcie_lcr_extsync_en && common->bus_ops->extn_synch_en)
 		common->bus_ops->extn_synch_en(common);
 
-mutex_unlock:
 	mutex_unlock(&sc->mutex);
 
 	ath9k_ps_restore(sc);
 
-	return r;
+	return 0;
 }
 
 static void ath9k_tx(struct ieee80211_hw *hw,

drivers/net/wireless/ath/ath9k/pci.c

@@ -326,7 +326,8 @@ static int ath_pci_resume(struct device *device)
 	struct pci_dev *pdev = to_pci_dev(device);
 	struct ieee80211_hw *hw = pci_get_drvdata(pdev);
 	struct ath_softc *sc = hw->priv;
-	struct ath_common *common = ath9k_hw_common(sc->sc_ah);
+	struct ath_hw *ah = sc->sc_ah;
+	struct ath_common *common = ath9k_hw_common(ah);
 	u32 val;
 
 	/*
@@ -339,6 +340,7 @@ static int ath_pci_resume(struct device *device)
 		pci_write_config_dword(pdev, 0x40, val & 0xffff00ff);
 
 	ath_pci_aspm_init(common);
+	ah->reset_power_on = false;
 
 	return 0;
 }