rapidio: add device access check into the enumeration

Add explicit device access check before performing device enumeration.
This gives a chance to clear possible link error conditions by issuing
safe maintenance read request(s).

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, 6 insertions, 0 deletions

diff --git a/drivers/rapidio/rio-scan.c b/drivers/rapidio/rio-scan.c
index d2ea01872d6a..e3efdf93df5a 100644
--- a/drivers/rapidio/rio-scan.c
+++ b/drivers/rapidio/rio-scan.c
@@ -762,6 +762,12 @@ static int __devinit rio_enum_peer(struct rio_net *net, struct rio_mport *port,
         u16 destid;
         int tmp;
 
+        if (rio_mport_chk_dev_access(port,
+                        RIO_ANY_DESTID(port->sys_size), hopcount)) {
+                pr_debug("RIO: device access check failed\n");
+                return -1;
+        }
+
         if (rio_get_host_deviceid_lock(port, hopcount) == port->host_deviceid) {
                 pr_debug("RIO: PE already discovered by this host\n");
                 /*