rapidio: add handling of redundant routes

Detects RIO link to the already enumerated device and properly sets links
between device objects.  Changes to the enumeration/discovery logic:

1. Use Master Enable bit to signal end of the enumeration - agents may
   start their discovery process as soon as they see this bit set
   (Component Tag register was used before for this purpose).

2. Enumerator sets Component Tag (!= 0) immediately during device
   setup.  This allows to identify the device if the redundant route
   exists in a RIO system.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Thomas Moll <thomas.moll@sysgo.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Micha Nelissen <micha@neli.hopto.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 54 insertions, 51 deletions

diff --git a/drivers/rapidio/rio-scan.c b/drivers/rapidio/rio-scan.c
index e3efdf93df5a..1eb82c4c712e 100644
--- a/drivers/rapidio/rio-scan.c
+++ b/drivers/rapidio/rio-scan.c
@@ -48,7 +48,7 @@ DEFINE_SPINLOCK(rio_global_list_lock);
 static int next_destid = 0;
 static int next_switchid = 0;
 static int next_net = 0;
-static int next_comptag;
+static int next_comptag = 1;
 
 static struct timer_list rio_enum_timer =
 TIMER_INITIALIZER(rio_enum_timeout, 0, 0);
@@ -121,27 +121,6 @@ static int rio_clear_locks(struct rio_mport *port)
         u32 result;
         int ret = 0;
 
-        /* Assign component tag to all devices */
-        next_comptag = 1;
-        rio_local_write_config_32(port, RIO_COMPONENT_TAG_CSR, next_comptag++);
-
-        list_for_each_entry(rdev, &rio_devices, global_list) {
-                /* Mark device as discovered */
-                rio_read_config_32(rdev,
-                                   rdev->phys_efptr + RIO_PORT_GEN_CTL_CSR,
-                                   &result);
-                rio_write_config_32(rdev,
-                                    rdev->phys_efptr + RIO_PORT_GEN_CTL_CSR,
-                                    result | RIO_PORT_GEN_DISCOVERED);
-
-                rio_write_config_32(rdev, RIO_COMPONENT_TAG_CSR, next_comptag);
-                rdev->comp_tag = next_comptag++;
-                if (next_comptag >= 0x10000) {
-                        pr_err("RIO: Component Tag Counter Overflow\n");
-                        break;
-                }
-        }
-
         /* Release host device id locks */
         rio_local_write_config_32(port, RIO_HOST_DID_LOCK_CSR,
                                   port->host_deviceid);
@@ -162,6 +141,15 @@ static int rio_clear_locks(struct rio_mport *port)
                                rdev->vid, rdev->did);
                         ret = -EINVAL;
                 }
+
+                /* Mark device as discovered and enable master */
+                rio_read_config_32(rdev,
+                                   rdev->phys_efptr + RIO_PORT_GEN_CTL_CSR,
+                                   &result);
+                result |= RIO_PORT_GEN_DISCOVERED | RIO_PORT_GEN_MASTER;
+                rio_write_config_32(rdev,
+                                    rdev->phys_efptr + RIO_PORT_GEN_CTL_CSR,
+                                    result);
         }
 
         return ret;
@@ -430,6 +418,17 @@ static struct rio_dev __devinit *rio_setup_device(struct rio_net *net,
         rio_mport_read_config_32(port, destid, hopcount, RIO_DST_OPS_CAR,
                                  &rdev->dst_ops);
 
+        if (do_enum) {
+                /* Assign component tag to device */
+                if (next_comptag >= 0x10000) {
+                        pr_err("RIO: Component Tag Counter Overflow\n");
+                        goto cleanup;
+                }
+                rio_mport_write_config_32(port, destid, hopcount,
+                                          RIO_COMPONENT_TAG_CSR, next_comptag);
+                rdev->comp_tag = next_comptag++;
+        }
+
         if (rio_device_has_destid(port, rdev->src_ops, rdev->dst_ops)) {
                 if (do_enum) {
                         rio_set_device_id(port, destid, hopcount, next_destid);
@@ -726,21 +725,6 @@ static u16 rio_get_host_deviceid_lock(struct rio_mport *port, u8 hopcount)
 }
 
 /**
- * rio_net_add_mport- Add a master port to a RIO network
- * @net: RIO network
- * @port: Master port to add
- *
- * Adds a master port to the network list of associated master
- * ports..
- */
-static void rio_net_add_mport(struct rio_net *net, struct rio_mport *port)
-{
-        spin_lock(&rio_global_list_lock);
-        list_add_tail(&port->nnode, &net->mports);
-        spin_unlock(&rio_global_list_lock);
-}
-
-/**
  * rio_enum_peer- Recursively enumerate a RIO network through a master port
  * @net: RIO network being enumerated
  * @port: Master port to send transactions
@@ -760,6 +744,7 @@ static int __devinit rio_enum_peer(struct rio_net *net, struct rio_mport *port,
         int sw_inport;
         struct rio_dev *rdev;
         u16 destid;
+        u32 regval;
         int tmp;
 
         if (rio_mport_chk_dev_access(port,
@@ -772,9 +757,21 @@ static int __devinit rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                 pr_debug("RIO: PE already discovered by this host\n");
                 /*
                  * Already discovered by this host. Add it as another
-                 * master port for the current network.
+                 * link to the existing device.
                  */
-                rio_net_add_mport(net, port);
+                rio_mport_read_config_32(port, RIO_ANY_DESTID(port->sys_size),
+                                hopcount, RIO_COMPONENT_TAG_CSR, &regval);
+
+                if (regval) {
+                        rdev = rio_get_comptag((regval & 0xffff), NULL);
+
+                        if (rdev && prev && rio_is_switch(prev)) {
+                                pr_debug("RIO: redundant path to %s\n",
+                                         rio_name(rdev));
+                                prev->rswitch->nextdev[prev_port] = rdev;
+                        }
+                }
+
                 return 0;
         }
 
@@ -925,10 +922,11 @@ static int __devinit rio_enum_peer(struct rio_net *net, struct rio_mport *port,
  */
 static int rio_enum_complete(struct rio_mport *port)
 {
-        u32 tag_csr;
+        u32 regval;
 
-        rio_local_read_config_32(port, RIO_COMPONENT_TAG_CSR, &tag_csr);
-        return (tag_csr & 0xffff) ? 1 : 0;
+        rio_local_read_config_32(port, port->phys_efptr + RIO_PORT_GEN_CTL_CSR,
+                                 &regval);
+        return (regval & RIO_PORT_GEN_MASTER) ? 1 : 0;
 }
 
 /**
@@ -991,6 +989,8 @@ rio_disc_peer(struct rio_net *net, struct rio_mport *port, u16 destid,
                                                 break;
                                 }
 
+                                if (ndestid == RIO_ANY_DESTID(port->sys_size))
+                                        continue;
                                 rio_unlock_device(port, destid, hopcount);
                                 if (rio_disc_peer
                                     (net, port, ndestid, hopcount + 1) < 0)
@@ -1163,6 +1163,10 @@ int __devinit rio_enum_mport(struct rio_mport *mport)
                 /* Enable Input Output Port (transmitter reviever) */
                 rio_enable_rx_tx_port(mport, 1, 0, 0, 0);
 
+                /* Set component tag for host */
+                rio_local_write_config_32(mport, RIO_COMPONENT_TAG_CSR,
+                                          next_comptag++);
+
                 if (rio_enum_peer(net, mport, 0, NULL, 0) < 0) {
                         /* A higher priority host won enumeration, bail. */
                         printk(KERN_INFO
diff --git a/drivers/rapidio/rio.c b/drivers/rapidio/rio.c
index fa5e3cbe4c83..7f18a65c4ed0 100644
--- a/drivers/rapidio/rio.c
+++ b/drivers/rapidio/rio.c
@@ -443,7 +443,7 @@ rio_mport_get_physefb(struct rio_mport *port, int local,
  * @from is not %NULL, searches continue from next device on the global
  * list.
  */
-static struct rio_dev *rio_get_comptag(u32 comp_tag, struct rio_dev *from)
+struct rio_dev *rio_get_comptag(u32 comp_tag, struct rio_dev *from)
 {
         struct list_head *n;
         struct rio_dev *rdev;
@@ -507,7 +507,7 @@ static int
 rio_chk_dev_route(struct rio_dev *rdev, struct rio_dev **nrdev, int *npnum)
 {
         u32 result;
-        int p_port, rc = -EIO;
+        int p_port, dstid, rc = -EIO;
         struct rio_dev *prev = NULL;
 
         /* Find switch with failed RIO link */
@@ -522,20 +522,18 @@ rio_chk_dev_route(struct rio_dev *rdev, struct rio_dev **nrdev, int *npnum)
         if (prev == NULL)
                 goto err_out;
 
-        /* Find port with failed RIO link */
-        for (p_port = 0;
-             p_port < RIO_GET_TOTAL_PORTS(prev->swpinfo); p_port++)
-                if (prev->rswitch->nextdev[p_port] == rdev)
-                        break;
+        dstid = (rdev->pef & RIO_PEF_SWITCH) ?
+                        rdev->rswitch->destid : rdev->destid;
+        p_port = prev->rswitch->route_table[dstid];
 
-        if (p_port < RIO_GET_TOTAL_PORTS(prev->swpinfo)) {
+        if (p_port != RIO_INVALID_ROUTE) {
                 pr_debug("RIO: link failed on [%s]-P%d\n",
                          rio_name(prev), p_port);
                 *nrdev = prev;
                 *npnum = p_port;
                 rc = 0;
         } else
-                pr_debug("RIO: failed to trace route to %s\n", rio_name(prev));
+                pr_debug("RIO: failed to trace route to %s\n", rio_name(rdev));
 err_out:
         return rc;
 }
diff --git a/drivers/rapidio/rio.h b/drivers/rapidio/rio.h
index d249a1205c7d..b1af414f15e6 100644
--- a/drivers/rapidio/rio.h
+++ b/drivers/rapidio/rio.h
@@ -38,6 +38,7 @@ extern int rio_std_route_get_entry(struct rio_mport *mport, u16 destid,
 extern int rio_std_route_clr_table(struct rio_mport *mport, u16 destid,
                                    u8 hopcount, u16 table);
 extern int rio_set_port_lockout(struct rio_dev *rdev, u32 pnum, int lock);
+extern struct rio_dev *rio_get_comptag(u32 comp_tag, struct rio_dev *from);
 
 /* Structures internal to the RIO core code */
 extern struct device_attribute rio_dev_attrs[];