network_device/flxnet_dev.c

@@ -30,13 +30,6 @@
 
 #define DRV_NAME "flxnet_dev"
 
-/*
-	- disable tx and rx on the peers without "link" present
-	- it's possible to make TX queue circular buffer lockless
-	- user interrupts instead of timer; use NAPI
-*/
-
-
 struct mutex flxnet_mutex;
 u32 message_level;
 
@@ -211,19 +204,19 @@ struct flxnet_peer *find_peer_for_netdev(struct net_device *dev) {
 }
 
 
-// removes the peer from the network, assumes that peer_mutex is held
+// removes the peer from the network
 void flxnet_remove_peer(struct flxnet_peer *peer) {
 	int rv;
-	set_carrier(peer, false);
-	netif_stop_queue(peer->flxnet);
-	netif_carrier_off(peer->flxnet);
-	unregister_netdev(peer->flxnet);
-	free_netdev(peer->flxnet);
-	kfree(peer->tx_queue.packets);
 
 	if (message_level & NETIF_MSG_LINK)
 		pr_info("flxnet_dev: removing peer %p from the network\n", peer);
 
+	mutex_lock(&peer_mutex);
+    set_carrier(peer, false);
+	unregister_netdev(peer->flxnet);
+	free_netdev(peer->flxnet);
+	kfree(peer->tx_queue.packets);
+
 	rv = atomic_dec_return(&peer_count);
 	if (rv < 0) {
 		pr_err("flxnet_dev: BUG in %s: peer_count = %d, less than 0\n",
@@ -233,50 +226,9 @@ void flxnet_remove_peer(struct flxnet_peer *peer) {
 
 	list_del(&peer->list_head);
 	kfree(peer);
+	mutex_unlock(&peer_mutex);
 }
 
-
-// mark as not reserved so that peer modules can be removed
-//void flxnet_release_all_peers(void) {
-//	struct flxnet_peer *peer;
-//	struct flxnet_peer *tmp;
-//	
-//	mutex_lock(&peer_mutex);
-//	list_for_each_entry_safe(peer, tmp, &peers, list_head) {
-//		if (peer->reserved) {
-//			module_put(peer->owner);
-//			peer->reserved = false;
-//		} else {
-//			if (message_level & NETIF_MSG_DRV)
-//				pr_info("flxnet_dev: trying to release peer %p, which is not reserved, skipping\n", peer);
-//		}
-//	}
-//	mutex_unlock(&peer_mutex);
-//}
-
-
-// mark as reserved so that peer modules cannot be removed and iomem stay there
-//void flxnet_reserve_all_peers(void) {
-//	struct flxnet_peer *peer;
-//	struct flxnet_peer *tmp;
-//
-//	mutex_lock(&peer_mutex);
-//	list_for_each_entry_safe(peer, tmp, &peers, list_head) {
-//		if (!peer->reserved) {
-//			peer->reserved = try_module_get(peer->owner);
-//			if (!peer->reserved) {
-//				pr_err("flxnet_dev: failed to reserve peer %p, owner module is missing\n", peer);
-//				flxnet_remove_peer(peer);
-//			}
-//		} else {
-//			if (message_level & NETIF_MSG_DRV)
-//				pr_info("flxnet_dev: trying to reserve peer %p, which is already reserved, skipping\n", peer);
-//		}
-//	}
-//	mutex_unlock(&peer_mutex);
-//}
-
-
 static bool tx_queue_is_full(struct flxnet_peer *peer) {
 	bool rv;
 	unsigned long flags;
@@ -579,7 +531,6 @@ static inline void check_carrier(struct flxnet_peer *peer) {
 		if (!netif_carrier_ok(peer->flxnet)) {
 			if (message_level & NETIF_MSG_IFUP)
 				pr_info("flxnet_dev: status carrier changed to %d\n", carrier);
-			netif_start_queue(peer->flxnet);
 			netif_carrier_on(peer->flxnet);
 		}
 	}
@@ -587,7 +538,6 @@ static inline void check_carrier(struct flxnet_peer *peer) {
 		if (netif_carrier_ok(peer->flxnet)) {
 			if (message_level & NETIF_MSG_IFDOWN)
 				pr_info("flxnet_dev: status carrier changed to %d\n", carrier);
-			netif_stop_queue(peer->flxnet);
 			netif_carrier_off(peer->flxnet);
 		}
 	}
@@ -605,7 +555,6 @@ void recv_timer_function(struct timer_list *timer_list) {
 bool can_transmit_packets(struct flxnet_peer *peer) {
 
 	if (is_magic_correct(peer) && can_accept_block(peer)) {
-		mutex_unlock(&peer_mutex);
 		return true;
 	}
 	return false;
@@ -712,8 +661,6 @@ int send_recv_thread(void *data) {
 int open(struct net_device *dev) {
 
 	mutex_lock(&flxnet_mutex);
-
-	//flxnet_reserve_all_peers(); // reserve the modules that supplied the peers	
 	tx_queue_reset(dev); 		// clear TX queue
 
 	// enable RX side
@@ -733,7 +680,6 @@ int open(struct net_device *dev) {
 	if (message_level & NETIF_MSG_IFUP)
 		pr_info("flxnet_dev: start netif queue\n");
 	netif_start_queue(dev);
-	netif_carrier_on(dev);
 
 	mutex_unlock(&flxnet_mutex);
 	return 0;
@@ -753,11 +699,8 @@ int stop(struct net_device *dev) {
 	if (message_level & NETIF_MSG_IFDOWN)
 		pr_info("flxnet_dev: stop netif queue\n");
 	netif_stop_queue(dev);
-	netif_carrier_off(dev);
 
 	tx_queue_reset(dev); 		// clear TX queue
-	//flxnet_release_all_peers(); // free the modules that supplied the peers
-
 	mutex_unlock(&flxnet_mutex);
 	
 	return 0;
@@ -1042,10 +985,12 @@ err_alloc_tx_queue:
 }
 
 
-// add a felix device to the network
+// add a peer device to the network
 struct flxnet_peer * flxnet_add_peer(void* __iomem base_address) {
 	struct flxnet_peer *peer;
 	pr_info("flxnet_dev: flxnet_add_peer %lX\n", (long unsigned int)base_address);
+
+	mutex_lock(&peer_mutex);
 	peer = kzalloc(sizeof(struct flxnet_peer), GFP_KERNEL);
 	if (IS_ERR(peer)) {
 		pr_err("flxnet_dev: can't allocate memory for struct flxnet_peer\n");
@@ -1071,7 +1016,7 @@ struct flxnet_peer * flxnet_add_peer(void* __iomem base_address) {
 	if (message_level & NETIF_MSG_IFUP)
 		pr_info("flxnet_dev: status_carrier %d\n", status_carrier(peer));
 
-	list_add(&peers, &peer->list_head);
+	list_add(&peer->list_head, &peers);
 	atomic_inc(&peer_count);
 	mutex_unlock(&peer_mutex);
 
@@ -1091,24 +1036,8 @@ int __init flxnet_dev_init(void) {
 	return 0;
 }
 
-// unregister the network device if necessary
 void __exit flxnet_dev_exit(void) {	
-	
-	struct flxnet_peer *peer, *tmp; 
-
-	if (!list_empty(&peers)) {
-		mutex_lock(&peer_mutex);
-		list_for_each_entry_safe(peer, tmp, &peers, list_head) {
-			netif_stop_queue(peer->flxnet);
-			netif_carrier_off(peer->flxnet);
-			unregister_netdev(peer->flxnet);
-			free_netdev(peer->flxnet);
-			kfree(peer->tx_queue.packets);
-		}
-		pr_info("flxnet_dev: unregistred network device\n");
-	}
 	pr_info("flxnet_dev: removing %s driver\n", DRV_NAME);
-	mutex_unlock(&peer_mutex);
 	mutex_destroy(&peer_mutex);
 	mutex_destroy(&flxnet_mutex);
 }

network_device/flxnet_pcie.c

@@ -37,7 +37,6 @@ struct pcie_flx_serial_device {
 	struct pci_dev *pdev;		// pci device struct from probe()
 	void __iomem *bar;			// addresses for the relevant BAR
 	int bar_idx;
-	spinlock_t lock;			// protects concurrent access
 	unsigned int flags;
 
 	struct flxnet_peer * peer;
@@ -66,11 +65,16 @@ static int flxnet_pcie_init(void) {
 	// if a PCI device is found, a pointer to its device structure is returned
 	pdev = pci_get_device(0x10dc, 0x0427, pdev);
 
+	if (pdev == NULL) {
+		pr_info("flxnet_pcie: no pcie devices available\n");
+		return 0;
+	}
+
 	// pdev returns NULL when all the PCI devices are found and stops searching
 	while (pdev != NULL) {
 		pr_info("flxnet_pcie: found %s \n", pci_name(pdev));
 		rv = configure_pcie_device(pdev);
-		pci_dev_put(pdev);
+
 		if (rv < 0) {			
 			pr_warn("flxnet_pcie: failed to configure %s\n", pci_name(pdev));
 		}
@@ -84,6 +88,7 @@ static int flxnet_pcie_init(void) {
 	return rv;	
 }
 
+
 // deconfigure pcie devices if necessary, remove module
 static void flxnet_pcie_exit(void) {
 
@@ -95,8 +100,9 @@ static void flxnet_pcie_exit(void) {
 		pr_info("flxnet_pcie: list not empty - deconfiguring PCIe devices\n");
 		list_for_each_entry_safe(fdev, tmp, &flx_devices, list_head) {
 			flxnet_remove_peer(fdev->peer);
+			list_del(&fdev->list_head);
 			deconfigure_device(fdev);
-		}	
+		}
 	}
 	else {
 		pr_info("flxnet_pcie: list is empty - nothing to deconfigure\n");
@@ -104,6 +110,7 @@ static void flxnet_pcie_exit(void) {
 }
 
 
+// configure a felix serial device
 static int configure_pcie_device(struct pci_dev *pdev) {
 
 	int rv;
@@ -120,7 +127,6 @@ static int configure_pcie_device(struct pci_dev *pdev) {
 	if (!fdev)
 		return -ENOMEM;
 
-	spin_lock_init(&fdev->lock);
 	fdev->magic = FLX_PCIE_MAGIC;
 	fdev->pdev = pdev;
 	fdev->bar_idx = bar_idx;
@@ -132,6 +138,7 @@ static int configure_pcie_device(struct pci_dev *pdev) {
 		pr_err("flxnet_pcie: pci_enable_device() failed, %d\n", rv);
 		goto err_enable;
 	}
+	pci_dev_get(pdev);
 
 	// reserve the selected bar for this driver
 	pr_info("flxnet_pcie: reserving BAR memory\n");
@@ -146,7 +153,8 @@ static int configure_pcie_device(struct pci_dev *pdev) {
 	rv = map_single_bar(fdev, bar_idx);
 	if (rv < 0) {
 		goto warn_nobar;
-	} else if (rv < MIN_MMAP_SIZE) {
+	}
+	else if (rv < MIN_MMAP_SIZE) {
 		pr_err("flxnet_pcie: mapped region is too small (%d bytes < %d)\n",
 			rv, MIN_MMAP_SIZE);
 		goto err_peer;
@@ -161,6 +169,7 @@ static int configure_pcie_device(struct pci_dev *pdev) {
 		goto err_peer;
 	}
 
+
 	// device structure
 	list_add(&fdev->list_head, &flx_devices);
 	pr_info("flxnet_pcie: added peer to list flx_devices\n");
@@ -207,20 +216,17 @@ static void deconfigure_device(struct pcie_flx_serial_device *fdev) {
 
 	if (!pdev) {
 		pr_err("flxnet_pcie: pci_dev ptr is NULL\n");
-		goto err_exit;
 	}
 
 	if (fdev->bar) {
 		pci_iounmap(pdev, fdev->bar);		
 	} else {
-		pr_err("flxnet_pcie: BAR memory is not mapped\n");
+		pr_warn("flxnet_pcie: BAR memory is not mapped\n");
 	}
 
+	pci_dev_put(pdev);
 	pci_disable_device(pdev);
 	pci_release_region(pdev, bar_idx);
-	
-err_exit:
-	list_del(&fdev->list_head);
 	kfree(fdev);
 }