[PATCH] rapidio: fix multi-switch enumeration

This patch contains two fixes for RapisIO enumeration logic:

1. Fix enumeration in configurations with multiple switches. The patch adds:

   a. Enumeration of an empty switch.  Empty switch is a switch that
      does not have any endpoint devices attached to it (except host device
      or previous switch in a chain).  New code assigns a phony destination
      ID associated with the switch and sets up corresponding routes.

   b. Adds a second pass to the enumeration to setup routes to
      devices discovered after switch was scanned.

2. Fix enumeration failure when riohdid parameter has non-zero value.
   Current version fails to setup response path to the host when it has
   destination ID other that 0.

Signed-off-by: Alexandre Bounine <alexandreb@tundra.com>
Acked-by: Matt Porter <mporter@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 88 insertions, 31 deletions

diff --git a/drivers/rapidio/rio-scan.c b/drivers/rapidio/rio-scan.c
index 7bf7b2c88245..f935c1f71a58 100644
--- a/drivers/rapidio/rio-scan.c
+++ b/drivers/rapidio/rio-scan.c
@@ -326,14 +326,17 @@ static struct rio_dev *rio_setup_device(struct rio_net *net,
         rio_mport_read_config_32(port, destid, hopcount, RIO_DST_OPS_CAR,
                                  &rdev->dst_ops);
 
-        if (rio_device_has_destid(port, rdev->src_ops, rdev->dst_ops)
-            && do_enum) {
-                rio_set_device_id(port, destid, hopcount, next_destid);
-                rdev->destid = next_destid++;
-                if (next_destid == port->host_deviceid)
-                        next_destid++;
+        if (rio_device_has_destid(port, rdev->src_ops, rdev->dst_ops)) {
+                if (do_enum) {
+                        rio_set_device_id(port, destid, hopcount, next_destid);
+                        rdev->destid = next_destid++;
+                        if (next_destid == port->host_deviceid)
+                                next_destid++;
+                } else
+                        rdev->destid = rio_get_device_id(port, destid, hopcount);
         } else
-                rdev->destid = rio_get_device_id(port, destid, hopcount);
+                /* Switch device has an associated destID */
+                rdev->destid = RIO_INVALID_DESTID;
 
         /* If a PE has both switch and other functions, show it as a switch */
         if (rio_is_switch(rdev)) {
@@ -347,7 +350,7 @@ static struct rio_dev *rio_setup_device(struct rio_net *net,
                 }
                 rswitch->switchid = next_switchid;
                 rswitch->hopcount = hopcount;
-                rswitch->destid = 0xffff;
+                rswitch->destid = destid;
                 /* Initialize switch route table */
                 for (rdid = 0; rdid < RIO_MAX_ROUTE_ENTRIES; rdid++)
                         rswitch->route_table[rdid] = RIO_INVALID_ROUTE;
@@ -422,7 +425,7 @@ rio_sport_is_active(struct rio_mport *port, u16 destid, u8 hopcount, int sport)
 /**
  * rio_route_add_entry- Add a route entry to a switch routing table
  * @mport: Master port to send transaction
- * @rdev: Switch device
+ * @rswitch: Switch device
  * @table: Routing table ID
  * @route_destid: Destination ID to be routed
  * @route_port: Port number to be routed
@@ -434,18 +437,18 @@ rio_sport_is_active(struct rio_mport *port, u16 destid, u8 hopcount, int sport)
  * %RIO_GLOBAL_TABLE in @table. Returns %0 on success or %-EINVAL
  * on failure.
  */
-static int rio_route_add_entry(struct rio_mport *mport, struct rio_dev *rdev,
+static int rio_route_add_entry(struct rio_mport *mport, struct rio_switch *rswitch,
                                u16 table, u16 route_destid, u8 route_port)
 {
-        return rdev->rswitch->add_entry(mport, rdev->rswitch->destid,
-                                        rdev->rswitch->hopcount, table,
+        return rswitch->add_entry(mport, rswitch->destid,
+                                        rswitch->hopcount, table,
                                         route_destid, route_port);
 }
 
 /**
  * rio_route_get_entry- Read a route entry in a switch routing table
  * @mport: Master port to send transaction
- * @rdev: Switch device
+ * @rswitch: Switch device
  * @table: Routing table ID
  * @route_destid: Destination ID to be routed
  * @route_port: Pointer to read port number into
@@ -458,11 +461,11 @@ static int rio_route_add_entry(struct rio_mport *mport, struct rio_dev *rdev,
  * on failure.
  */
 static int
-rio_route_get_entry(struct rio_mport *mport, struct rio_dev *rdev, u16 table,
+rio_route_get_entry(struct rio_mport *mport, struct rio_switch *rswitch, u16 table,
                     u16 route_destid, u8 * route_port)
 {
-        return rdev->rswitch->get_entry(mport, rdev->rswitch->destid,
-                                        rdev->rswitch->hopcount, table,
+        return rswitch->get_entry(mport, rswitch->destid,
+                                        rswitch->hopcount, table,
                                         route_destid, route_port);
 }
 
@@ -552,6 +555,8 @@ static int rio_enum_peer(struct rio_net *net, struct rio_mport *port,
         int port_num;
         int num_ports;
         int cur_destid;
+        int sw_destid;
+        int sw_inport;
         struct rio_dev *rdev;
         u16 destid;
         int tmp;
@@ -594,15 +599,17 @@ static int rio_enum_peer(struct rio_net *net, struct rio_mport *port,
 
         if (rio_is_switch(rdev)) {
                 next_switchid++;
+                sw_inport = rio_get_swpinfo_inport(port, RIO_ANY_DESTID, hopcount);
+                rio_route_add_entry(port, rdev->rswitch, RIO_GLOBAL_TABLE,
+                                    port->host_deviceid, sw_inport);
+                rdev->rswitch->route_table[port->host_deviceid] = sw_inport;
 
                 for (destid = 0; destid < next_destid; destid++) {
-                        rio_route_add_entry(port, rdev, RIO_GLOBAL_TABLE,
-                                            destid, rio_get_swpinfo_inport(port,
-                                                                           RIO_ANY_DESTID,
-                                                                           hopcount));
-                        rdev->rswitch->route_table[destid] =
-                            rio_get_swpinfo_inport(port, RIO_ANY_DESTID,
-                                                   hopcount);
+                        if (destid == port->host_deviceid)
+                                continue;
+                        rio_route_add_entry(port, rdev->rswitch, RIO_GLOBAL_TABLE,
+                                            destid, sw_inport);
+                        rdev->rswitch->route_table[destid] = sw_inport;
                 }
 
                 num_ports =
@@ -610,9 +617,9 @@ static int rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                 pr_debug(
                     "RIO: found %s (vid %4.4x did %4.4x) with %d ports\n",
                     rio_name(rdev), rdev->vid, rdev->did, num_ports);
+                sw_destid = next_destid;
                 for (port_num = 0; port_num < num_ports; port_num++) {
-                        if (rio_get_swpinfo_inport
-                            (port, RIO_ANY_DESTID, hopcount) == port_num)
+                        if (sw_inport == port_num)
                                 continue;
 
                         cur_destid = next_destid;
@@ -622,7 +629,7 @@ static int rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                                 pr_debug(
                                     "RIO: scanning device on port %d\n",
                                     port_num);
-                                rio_route_add_entry(port, rdev,
+                                rio_route_add_entry(port, rdev->rswitch,
                                                     RIO_GLOBAL_TABLE,
                                                     RIO_ANY_DESTID, port_num);
 
@@ -633,7 +640,9 @@ static int rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                                 if (next_destid > cur_destid) {
                                         for (destid = cur_destid;
                                              destid < next_destid; destid++) {
-                                                rio_route_add_entry(port, rdev,
+                                                if (destid == port->host_deviceid)
+                                                        continue;
+                                                rio_route_add_entry(port, rdev->rswitch,
                                                                     RIO_GLOBAL_TABLE,
                                                                     destid,
                                                                     port_num);
@@ -641,10 +650,18 @@ static int rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                                                     route_table[destid] =
                                                     port_num;
                                         }
-                                        rdev->rswitch->destid = cur_destid;
                                 }
                         }
                 }
+
+                /* Check for empty switch */
+                if (next_destid == sw_destid) {
+                        next_destid++;
+                        if (next_destid == port->host_deviceid)
+                                next_destid++;
+                }
+
+                rdev->rswitch->destid = sw_destid;
         } else
                 pr_debug("RIO: found %s (vid %4.4x did %4.4x)\n",
                     rio_name(rdev), rdev->vid, rdev->did);
@@ -721,7 +738,7 @@ rio_disc_peer(struct rio_net *net, struct rio_mport *port, u16 destid,
                                     port_num);
                                 for (ndestid = 0; ndestid < RIO_ANY_DESTID;
                                      ndestid++) {
-                                        rio_route_get_entry(port, rdev,
+                                        rio_route_get_entry(port, rdev->rswitch,
                                                             RIO_GLOBAL_TABLE,
                                                             ndestid,
                                                             &route_port);
@@ -798,6 +815,44 @@ static struct rio_net __devinit *rio_alloc_net(struct rio_mport *port)
 }
 
 /**
+ * rio_update_route_tables- Updates route tables in switches
+ * @port: Master port associated with the RIO network
+ *
+ * For each enumerated device, ensure that each switch in a system
+ * has correct routing entries. Add routes for devices that where
+ * unknown dirung the first enumeration pass through the switch.
+ */
+static void rio_update_route_tables(struct rio_mport *port)
+{
+        struct rio_dev *rdev;
+        struct rio_switch *rswitch;
+        u8 sport;
+        u16 destid;
+
+        list_for_each_entry(rdev, &rio_devices, global_list) {
+
+                destid = (rio_is_switch(rdev))?rdev->rswitch->destid:rdev->destid;
+
+                list_for_each_entry(rswitch, &rio_switches, node) {
+
+                        if (rio_is_switch(rdev) && (rdev->rswitch == rswitch))
+                                continue;
+
+                        if (RIO_INVALID_ROUTE == rswitch->route_table[destid]) {
+
+                                sport = rio_get_swpinfo_inport(port,
+                                                rswitch->destid, rswitch->hopcount);
+
+                                if (rswitch->add_entry) {
+                                        rio_route_add_entry(port, rswitch, RIO_GLOBAL_TABLE, destid, sport);
+                                        rswitch->route_table[destid] = sport;
+                                }
+                        }
+                }
+        }
+}
+
+/**
  * rio_enum_mport- Start enumeration through a master port
  * @mport: Master port to send transactions
  *
@@ -838,6 +893,7 @@ int rio_enum_mport(struct rio_mport *mport)
                         rc = -EBUSY;
                         goto out;
                 }
+                rio_update_route_tables(mport);
                 rio_clear_locks(mport);
         } else {
                 printk(KERN_INFO "RIO: master port %d link inactive\n",
@@ -865,8 +921,8 @@ static void rio_build_route_tables(void)
             if (rio_is_switch(rdev))
                 for (i = 0; i < RIO_MAX_ROUTE_ENTRIES; i++) {
                         if (rio_route_get_entry
-                            (rdev->net->hport, rdev, RIO_GLOBAL_TABLE, i,
-                             &sport) < 0)
+                            (rdev->net->hport, rdev->rswitch, RIO_GLOBAL_TABLE,
+                             i, &sport) < 0)
                                 continue;
                         rdev->rswitch->route_table[i] = sport;
                 }
diff --git a/include/linux/rio.h b/include/linux/rio.h
index d93857056cb9..68e3f6853fa6 100644
--- a/include/linux/rio.h
+++ b/include/linux/rio.h
@@ -25,6 +25,7 @@
 
 #define RIO_ANY_DESTID          0xff
 #define RIO_NO_HOPCOUNT         -1
+#define RIO_INVALID_DESTID      0xffff
 
 #define RIO_MAX_MPORT_RESOURCES 16
 #define RIO_MAX_DEV_RESOURCES   16