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>

3 files changed, 14 insertions, 3 deletions

diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index 0425dd5dfcd3..31863cf8b6c4 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -1423,9 +1423,10 @@ static void outbound_phy_packet_callback(struct fw_packet *packet,
         /* 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 @@ static int ioctl_send_phy_packet(struct client *client, union ioctl_arg *arg)
         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 @@ static int ioctl_send_phy_packet(struct client *client, union ioctl_arg *arg)
         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);
 
diff --git a/drivers/firewire/core.h b/drivers/firewire/core.h
index 3102b6b63438..28621e44b111 100644
--- a/drivers/firewire/core.h
+++ b/drivers/firewire/core.h
@@ -234,4 +234,9 @@ void fw_fill_response(struct fw_packet *response, u32 *request_header,
 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 */
diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 08afccc66333..5f6bb2c53808 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -1068,6 +1068,9 @@ static int at_context_queue_packet(struct context *ctx,
                 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: