wcn36xx: Fix packet drop on resume

If the system is resumed because of an incoming packet, the wcn36xx RX
interrupts is fired before actual resuming of the wireless/mac80211
stack, causing any received packets to be simply dropped. E.g. a ping
request causes a system resume, but is dropped and so never forwarded
to the IP stack.

This change fixes that, disabling DMA interrupts on suspend to no pass
packets until mac80211 is resumed and ready to handle them.

Note that it's not incompatible with RX irq wake.
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@linaro.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1635150496-19290-1-git-send-email-loic.poulain@linaro.org

drivers/net/wireless/ath/wcn36xx/main.c

@@ -1124,6 +1124,13 @@ static int wcn36xx_suspend(struct ieee80211_hw *hw, struct cfg80211_wowlan *wow)
 			goto out;
 		ret = wcn36xx_smd_wlan_host_suspend_ind(wcn);
 	}
+
+	/* Disable IRQ, we don't want to handle any packet before mac80211 is
+	 * resumed and ready to receive packets.
+	 */
+	disable_irq(wcn->tx_irq);
+	disable_irq(wcn->rx_irq);
+
 out:
 	mutex_unlock(&wcn->conf_mutex);
 	return ret;
@@ -1146,6 +1153,10 @@ static int wcn36xx_resume(struct ieee80211_hw *hw)
 		wcn36xx_smd_ipv6_ns_offload(wcn, vif, false);
 		wcn36xx_smd_arp_offload(wcn, vif, false);
 	}
+
+	enable_irq(wcn->tx_irq);
+	enable_irq(wcn->rx_irq);
+
 	mutex_unlock(&wcn->conf_mutex);
 
 	return 0;