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>

1 files changed, 7 insertions, 9 deletions

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;
 }