ieee1394: support for slow links or slow 1394b phy ports

Add support for the following types of hardware:
 + nodes that have a link speed < PHY speed
 + 1394b PHYs that are less than S800 capable
 + 1394b/1394a adapter cable between two 1394b PHYs
Also, S1600 and S3200 are now supported if IEEE1394_SPEED_MAX is raised.

A probing function is added to nodemgr's config ROM fetching routine
which adjusts the allowable speed if an access problem was encountered.
Pros and Cons of the approach:
 + minimum code footprint to support this less widely used hardware
 + nearly no overhead for unaffected hardware
 - ineffective before nodemgr began to read the ROM of affected nodes
 - ineffective if ieee1394 is loaded with disable_nodemgr=1
The speed map CSRs which are published to the bus are not touched by the
patch.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Cc: Hakan Ardo <hakan@debian.org>
Cc: Calculex <linux@calculex.com>
Cc: Robert J. Kosinski <robk@cmcherald.com>
Signed-off-by: Ben Collins <bcollins@ubuntu.com>

1 files changed, 9 insertions, 5 deletions

diff --git a/drivers/ieee1394/ieee1394_core.c b/drivers/ieee1394/ieee1394_core.c
index be6854e25ad4..c83e2b8295e3 100644
--- a/drivers/ieee1394/ieee1394_core.c
+++ b/drivers/ieee1394/ieee1394_core.c
@@ -285,9 +285,9 @@ static int check_selfids(struct hpsb_host *host)
 
 static void build_speed_map(struct hpsb_host *host, int nodecount)
 {
-	u8 speedcap[nodecount];
 	u8 cldcnt[nodecount];
 	u8 *map = host->speed_map;
+	u8 *speedcap = host->speed;
 	struct selfid *sid;
 	struct ext_selfid *esid;
 	int i, j, n;
@@ -354,6 +354,11 @@ static void build_speed_map(struct hpsb_host *host, int nodecount)
 			}
 		}
 	}
+
+	/* assume maximum speed for 1394b PHYs, nodemgr will correct it */
+	for (n = 0; n < nodecount; n++)
+		if (speedcap[n] == 3)
+			speedcap[n] = IEEE1394_SPEED_MAX;
 }
 
 
@@ -554,11 +559,10 @@ int hpsb_send_packet(struct hpsb_packet *packet)
 		return 0;
 	}
 
-	if (packet->type == hpsb_async && packet->node_id != ALL_NODES) {
+	if (packet->type == hpsb_async &&
+	    NODEID_TO_NODE(packet->node_id) != ALL_NODES)
 		packet->speed_code =
-			host->speed_map[NODEID_TO_NODE(host->node_id) * 64
-				       + NODEID_TO_NODE(packet->node_id)];
-	}
+			host->speed[NODEID_TO_NODE(packet->node_id)];
 
 	dump_packet("send packet", packet->header, packet->header_size, packet->speed_code);