commit cc550216ae9a2993ef3973464714dc1a39ab1f86
author Stefan Richter <stefanr@s5r6.in-berlin.de> Sun Jul 18 13:00:50 2010 +0200
committer Stefan Richter <stefanr@s5r6.in-berlin.de> Fri Jul 23 13:36:28 2010 +0200
tree 62ffde836c83fe44b7a9edc01d00bcb9ad4f4ad6
parent bf54e1462b9192fdef7ea9e2bc44fdc16a4b87bc

firewire: cdev: add PHY pinging

This extends the FW_CDEV_IOC_SEND_PHY_PACKET ioctl() for /dev/fw* to be
useful for ping time measurements.  One application for it would be gap
count optimization in userspace that is based on ping times rather than
hop count.  (The latter is implemented in firewire-core itself but is
not applicable to beta PHYs that act as repeater.)

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/core-cdev.c

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 0425dd5..31863cf 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -1423,9 +1423,10 @@
 	/* stale generation; cancelled; on certain controllers: no ack */
 	default:		e->phy_packet.rcode = status;		break;
 	}
+	e->phy_packet.data[0] = packet->timestamp;
 
-	queue_event(e->client, &e->event,
-		    &e->phy_packet, sizeof(e->phy_packet), NULL, 0);
+	queue_event(e->client, &e->event, &e->phy_packet,
+		    sizeof(e->phy_packet) + e->phy_packet.length, NULL, 0);
 	client_put(e->client);
 }
 
@@ -1439,7 +1440,7 @@
 	if (!client->device->is_local)
 		return -ENOSYS;
 
-	e = kzalloc(sizeof(*e), GFP_KERNEL);
+	e = kzalloc(sizeof(*e) + 4, GFP_KERNEL);
 	if (e == NULL)
 		return -ENOMEM;
 
@@ -1453,6 +1454,8 @@
 	e->p.callback		= outbound_phy_packet_callback;
 	e->phy_packet.closure	= a->closure;
 	e->phy_packet.type	= FW_CDEV_EVENT_PHY_PACKET_SENT;
+	if (is_ping_packet(a->data))
+			e->phy_packet.length = 4;
 
 	card->driver->send_request(card, &e->p);
 

drivers/firewire/core.h

diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 3102b6b..28621e4 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -234,4 +234,9 @@
 void fw_send_phy_config(struct fw_card *card,
 			int node_id, int generation, int gap_count);
 
+static inline bool is_ping_packet(u32 *data)
+{
+	return (data[0] & 0xc0ffffff) == 0 && ~data[0] == data[1];
+}
+
 #endif /* _FIREWIRE_CORE_H */

drivers/firewire/ohci.c

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 08afccc..5f6bb2c 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -1068,6 +1068,9 @@
 		header[1] = cpu_to_le32(packet->header[0]);
 		header[2] = cpu_to_le32(packet->header[1]);
 		d[0].req_count = cpu_to_le16(12);
+
+		if (is_ping_packet(packet->header))
+			d[0].control |= cpu_to_le16(DESCRIPTOR_PING);
 		break;
 
 	case 4:

include/linux/firewire-cdev.h

diff --git a/include/linux/firewire-cdev.h b/include/linux/firewire-cdev.h
index b874091..da0fec7 100644
--- a/include/linux/firewire-cdev.h
+++ b/include/linux/firewire-cdev.h
@@ -294,7 +294,10 @@
  * @length:	Data length in bytes
  * @data:	Incoming data
  *
- * If @type is %FW_CDEV_EVENT_PHY_PACKET_SENT, @length is 0 and @data empty.
+ * If @type is %FW_CDEV_EVENT_PHY_PACKET_SENT, @length is 0 and @data empty,
+ * except in case of a ping packet:  Then, @length is 4, and @data[0] is the
+ * ping time in 49.152MHz clocks if @rcode is %RCODE_COMPLETE.
+ *
  * If @type is %FW_CDEV_EVENT_PHY_PACKET_RECEIVED, @length is 8 and @data
  * consists of the two PHY packet quadlets, in host byte order.
  */