msm: ipa: rmnet_ipa: stop TX queue on ap suspend

To prevent a race condition between AP (Application Processor)
suspend and TX packets, rmnet_ipa0 needs to stop TX queue on
suspend callback. This will ensure that once AP goes to suspend there are
no packets to be submitted to IPA.

Change-Id: Ia6877204f89865fe9629d1a404e1603422d99d2c
CRs-Fixed: 2029003
Acked-by: Ady Abraham <adya@qti.qualcomm.com>
Signed-off-by: Skylar Chang <chiaweic@codeaurora.org>

1 files changed, 19 insertions, 10 deletions

diff --git a/drivers/platform/msm/ipa/ipa_v3/rmnet_ipa.c b/drivers/platform/msm/ipa/ipa_v3/rmnet_ipa.c
index 6731150ce4e7..e3f8f4c0be46 100644
--- a/drivers/platform/msm/ipa/ipa_v3/rmnet_ipa.c
+++ b/drivers/platform/msm/ipa/ipa_v3/rmnet_ipa.c
@@ -2365,32 +2365,41 @@ static int rmnet_ipa_ap_suspend(struct device *dev)
 {
 	struct net_device *netdev = IPA_NETDEV();
 	struct ipa3_wwan_private *wwan_ptr;
+	int ret;
+
+	IPAWANDBG("Enter...\n");
 
-	IPAWANDBG_LOW("Enter...\n");
 	if (netdev == NULL) {
 		IPAWANERR("netdev is NULL.\n");
-		return 0;
+		ret = 0;
+		goto bail;
 	}
 
+	netif_tx_lock_bh(netdev);
 	wwan_ptr = netdev_priv(netdev);
 	if (wwan_ptr == NULL) {
 		IPAWANERR("wwan_ptr is NULL.\n");
-		return 0;
+		ret = 0;
+		goto unlock_and_bail;
 	}
 
 	/* Do not allow A7 to suspend in case there are oustanding packets */
 	if (atomic_read(&wwan_ptr->outstanding_pkts) != 0) {
 		IPAWANDBG("Outstanding packets, postponing AP suspend.\n");
-		return -EAGAIN;
+		ret = -EAGAIN;
+		goto unlock_and_bail;
 	}
 
 	/* Make sure that there is no Tx operation ongoing */
-	netif_tx_lock_bh(netdev);
+	netif_stop_queue(netdev);
 	ipa_rm_release_resource(IPA_RM_RESOURCE_WWAN_0_PROD);
-	netif_tx_unlock_bh(netdev);
-	IPAWANDBG_LOW("Exit\n");
+	ret = 0;
 
-	return 0;
+unlock_and_bail:
+	netif_tx_unlock_bh(netdev);
+bail:
+	IPAWANDBG("Exit with %d\n", ret);
+	return ret;
 }
 
 /**
@@ -2407,10 +2416,10 @@ static int rmnet_ipa_ap_resume(struct device *dev)
 {
 	struct net_device *netdev = IPA_NETDEV();
 
-	IPAWANDBG_LOW("Enter...\n");
+	IPAWANDBG("Enter...\n");
 	if (netdev)
 		netif_wake_queue(netdev);
-	IPAWANDBG_LOW("Exit\n");
+	IPAWANDBG("Exit\n");
 
 	return 0;
 }