NTB: Add indexed ports NTB API

There is some NTB hardware, which can combine more than just two domains
over NTB. For instance, some IDT PCIe-switches can have NTB-functions
activated on more than two-ports. The different domains are distinguished
by ports they are connected to. So the new port-related methods are added to
the NTB API:
 ntb_port_number() - return local port
 ntb_peer_port_count() - return number of peers local port can connect to
 ntb_peer_port_number(pdix) - return port number by it index
 ntb_peer_port_idx(port) - return port index by it number

Current test-drivers aren't changed much. They still support two-ports devices
for the time being while multi-ports hardware drivers aren't added.

By default port-related API is declared for two-ports hardware.
So corresponding hardware drivers won't need to implement it.

Signed-off-by: Serge Semin <[email protected]>
Signed-off-by: Jon Mason <[email protected]>

drivers/ntb/ntb.c

@@ -191,6 +191,60 @@ void ntb_db_event(struct ntb_dev *ntb, int vector)
 }
 EXPORT_SYMBOL(ntb_db_event);
 
+int ntb_default_port_number(struct ntb_dev *ntb)
+{
+	switch (ntb->topo) {
+	case NTB_TOPO_PRI:
+	case NTB_TOPO_B2B_USD:
+		return NTB_PORT_PRI_USD;
+	case NTB_TOPO_SEC:
+	case NTB_TOPO_B2B_DSD:
+		return NTB_PORT_SEC_DSD;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL(ntb_default_port_number);
+
+int ntb_default_peer_port_count(struct ntb_dev *ntb)
+{
+	return NTB_DEF_PEER_CNT;
+}
+EXPORT_SYMBOL(ntb_default_peer_port_count);
+
+int ntb_default_peer_port_number(struct ntb_dev *ntb, int pidx)
+{
+	if (pidx != NTB_DEF_PEER_IDX)
+		return -EINVAL;
+
+	switch (ntb->topo) {
+	case NTB_TOPO_PRI:
+	case NTB_TOPO_B2B_USD:
+		return NTB_PORT_SEC_DSD;
+	case NTB_TOPO_SEC:
+	case NTB_TOPO_B2B_DSD:
+		return NTB_PORT_PRI_USD;
+	default:
+		break;
+	}
+
+	return -EINVAL;
+}
+EXPORT_SYMBOL(ntb_default_peer_port_number);
+
+int ntb_default_peer_port_idx(struct ntb_dev *ntb, int port)
+{
+	int peer_port = ntb_default_peer_port_number(ntb, NTB_DEF_PEER_IDX);
+
+	if (peer_port == -EINVAL || port != peer_port)
+		return -EINVAL;
+
+	return 0;
+}
+EXPORT_SYMBOL(ntb_default_peer_port_idx);
+
 static int ntb_probe(struct device *dev)
 {
 	struct ntb_dev *ntb;

drivers/ntb/ntb_transport.c

@@ -95,6 +95,9 @@ MODULE_PARM_DESC(use_dma, "Use DMA engine to perform large data copy");
 
 static struct dentry *nt_debugfs_dir;
 
+/* Only two-ports NTB devices are supported */
+#define PIDX		NTB_DEF_PEER_IDX
+
 struct ntb_queue_entry {
 	/* ntb_queue list reference */
 	struct list_head entry;
@@ -1064,6 +1067,9 @@ static int ntb_transport_probe(struct ntb_client *self, struct ntb_dev *ndev)
 		dev_dbg(&ndev->dev,
 			"scratchpad is unsafe, proceed anyway...\n");
 
+	if (ntb_peer_port_count(ndev) != NTB_DEF_PEER_CNT)
+		dev_warn(&ndev->dev, "Multi-port NTB devices unsupported\n");
+
 	node = dev_to_node(&ndev->dev);
 
 	nt = kzalloc_node(sizeof(*nt), GFP_KERNEL, node);

drivers/ntb/test/ntb_perf.c

@@ -76,6 +76,7 @@
 #define DMA_RETRIES		20
 #define SZ_4G			(1ULL << 32)
 #define MAX_SEG_ORDER		20 /* no larger than 1M for kmalloc buffer */
+#define PIDX			NTB_DEF_PEER_IDX
 
 MODULE_LICENSE(DRIVER_LICENSE);
 MODULE_VERSION(DRIVER_VERSION);
@@ -766,6 +767,9 @@ static int perf_probe(struct ntb_client *client, struct ntb_dev *ntb)
 		return -EIO;
 	}
 
+	if (ntb_peer_port_count(ntb) != NTB_DEF_PEER_CNT)
+		dev_warn(&ntb->dev, "Multi-port NTB devices unsupported\n");
+
 	node = dev_to_node(&pdev->dev);
 
 	perf = kzalloc_node(sizeof(*perf), GFP_KERNEL, node);

drivers/ntb/test/ntb_pingpong.c

@@ -90,6 +90,9 @@ static unsigned long db_init = 0x7;
 module_param(db_init, ulong, 0644);
 MODULE_PARM_DESC(db_init, "Initial doorbell bits to ring on the peer");
 
+/* Only two-ports NTB devices are supported */
+#define PIDX		NTB_DEF_PEER_IDX
+
 struct pp_ctx {
 	struct ntb_dev			*ntb;
 	u64				db_bits;
@@ -230,6 +233,9 @@ static int pp_probe(struct ntb_client *client,
 		}
 	}
 
+	if (ntb_peer_port_count(ntb) != NTB_DEF_PEER_CNT)
+		dev_warn(&ntb->dev, "multi-port NTB is unsupported\n");
+
 	pp = kmalloc(sizeof(*pp), GFP_KERNEL);
 	if (!pp) {
 		rc = -ENOMEM;

drivers/ntb/test/ntb_tool.c

@@ -120,6 +120,8 @@ MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
 
 #define MAX_MWS 16
+/* Only two-ports devices are supported */
+#define PIDX	NTB_DEF_PEER_IDX
 
 static struct dentry *tool_dbgfs;
 
@@ -919,6 +921,9 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
 	if (ntb_spad_is_unsafe(ntb))
 		dev_dbg(&ntb->dev, "scratchpad is unsafe\n");
 
+	if (ntb_peer_port_count(ntb) != NTB_DEF_PEER_CNT)
+		dev_warn(&ntb->dev, "multi-port NTB is unsupported\n");
+
 	tc = kzalloc(sizeof(*tc), GFP_KERNEL);
 	if (!tc) {
 		rc = -ENOMEM;