rapidio: add switch locking during discovery

Add switch access locking during RapidIO discovery.  Access lock is
required when reading switch routing table contents due to indexed
mechanism of RT addressing.

Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Tested-by: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/rapidio/rio-scan.c b/drivers/rapidio/rio-scan.c
index 7f1a675..cbf0d5f 100644 (file)
--- a/drivers/rapidio/rio-scan.c
+++ b/drivers/rapidio/rio-scan.c
@@ -457,12 +457,87 @@ rio_sport_is_active(struct rio_mport *port, u16 destid, u8 hopcount, int sport)
 }
 
 /**
+ * rio_lock_device - Acquires host device lock for specified device
+ * @port: Master port to send transaction
+ * @destid: Destination ID for device/switch
+ * @hopcount: Hopcount to reach switch
+ * @wait_ms: Max wait time in msec (0 = no timeout)
+ *
+ * Attepts to acquire host device lock for specified device
+ * Returns 0 if device lock acquired or EINVAL if timeout expires.
+ */
+static int
+rio_lock_device(struct rio_mport *port, u16 destid, u8 hopcount, int wait_ms)
+{
+       u32 result;
+       int tcnt = 0;
+
+       /* Attempt to acquire device lock */
+       rio_mport_write_config_32(port, destid, hopcount,
+                                 RIO_HOST_DID_LOCK_CSR, port->host_deviceid);
+       rio_mport_read_config_32(port, destid, hopcount,
+                                RIO_HOST_DID_LOCK_CSR, &result);
+
+       while (result != port->host_deviceid) {
+               if (wait_ms != 0 && tcnt == wait_ms) {
+                       pr_debug("RIO: timeout when locking device %x:%x\n",
+                               destid, hopcount);
+                       return -EINVAL;
+               }
+
+               /* Delay a bit */
+               mdelay(1);
+               tcnt++;
+               /* Try to acquire device lock again */
+               rio_mport_write_config_32(port, destid,
+                       hopcount,
+                       RIO_HOST_DID_LOCK_CSR,
+                       port->host_deviceid);
+               rio_mport_read_config_32(port, destid,
+                       hopcount,
+                       RIO_HOST_DID_LOCK_CSR, &result);
+       }
+
+       return 0;
+}
+
+/**
+ * rio_unlock_device - Releases host device lock for specified device
+ * @port: Master port to send transaction
+ * @destid: Destination ID for device/switch
+ * @hopcount: Hopcount to reach switch
+ *
+ * Returns 0 if device lock released or EINVAL if fails.
+ */
+static int
+rio_unlock_device(struct rio_mport *port, u16 destid, u8 hopcount)
+{
+       u32 result;
+
+       /* Release device lock */
+       rio_mport_write_config_32(port, destid,
+                                 hopcount,
+                                 RIO_HOST_DID_LOCK_CSR,
+                                 port->host_deviceid);
+       rio_mport_read_config_32(port, destid, hopcount,
+               RIO_HOST_DID_LOCK_CSR, &result);
+       if ((result & 0xffff) != 0xffff) {
+               pr_debug("RIO: badness when releasing device lock %x:%x\n",
+                        destid, hopcount);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+/**
  * rio_route_add_entry- Add a route entry to a switch routing table
  * @mport: Master port to send transaction
  * @rswitch: Switch device
  * @table: Routing table ID
  * @route_destid: Destination ID to be routed
  * @route_port: Port number to be routed
+ * @lock: lock switch device flag
  *
  * Calls the switch specific add_entry() method to add a route entry
  * on a switch. The route table can be specified using the @table
@@ -471,12 +546,26 @@ 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_switch *rswitch,
-                              u16 table, u16 route_destid, u8 route_port)
+static int
+rio_route_add_entry(struct rio_mport *mport, struct rio_switch *rswitch,
+                   u16 table, u16 route_destid, u8 route_port, int lock)
 {
-       return rswitch->add_entry(mport, rswitch->destid,
+       int rc;
+
+       if (lock) {
+               rc = rio_lock_device(mport, rswitch->destid,
+                                    rswitch->hopcount, 1000);
+               if (rc)
+                       return rc;
+       }
+
+       rc = rswitch->add_entry(mport, rswitch->destid,
                                        rswitch->hopcount, table,
                                        route_destid, route_port);
+       if (lock)
+               rio_unlock_device(mport, rswitch->destid, rswitch->hopcount);
+
+       return rc;
 }
 
 /**
@@ -486,6 +575,7 @@ static int rio_route_add_entry(struct rio_mport *mport, struct rio_switch *rswit
  * @table: Routing table ID
  * @route_destid: Destination ID to be routed
  * @route_port: Pointer to read port number into
+ * @lock: lock switch device flag
  *
  * Calls the switch specific get_entry() method to read a route entry
  * in a switch. The route table can be specified using the @table
@@ -496,11 +586,24 @@ static int rio_route_add_entry(struct rio_mport *mport, struct rio_switch *rswit
  */
 static int
 rio_route_get_entry(struct rio_mport *mport, struct rio_switch *rswitch, u16 table,
-                   u16 route_destid, u8 * route_port)
+                   u16 route_destid, u8 *route_port, int lock)
 {
-       return rswitch->get_entry(mport, rswitch->destid,
+       int rc;
+
+       if (lock) {
+               rc = rio_lock_device(mport, rswitch->destid,
+                                    rswitch->hopcount, 1000);
+               if (rc)
+                       return rc;
+       }
+
+       rc = rswitch->get_entry(mport, rswitch->destid,
                                        rswitch->hopcount, table,
                                        route_destid, route_port);
+       if (lock)
+               rio_unlock_device(mport, rswitch->destid, rswitch->hopcount);
+
+       return rc;
 }
 
 /**
@@ -640,14 +743,14 @@ static int __devinit rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                sw_inport = rio_get_swpinfo_inport(port,
                                RIO_ANY_DESTID(port->sys_size), hopcount);
                rio_route_add_entry(port, rdev->rswitch, RIO_GLOBAL_TABLE,
-                                   port->host_deviceid, sw_inport);
+                                   port->host_deviceid, sw_inport, 0);
                rdev->rswitch->route_table[port->host_deviceid] = sw_inport;
 
                for (destid = 0; destid < next_destid; destid++) {
                        if (destid == port->host_deviceid)
                                continue;
                        rio_route_add_entry(port, rdev->rswitch, RIO_GLOBAL_TABLE,
-                                           destid, sw_inport);
+                                           destid, sw_inport, 0);
                        rdev->rswitch->route_table[destid] = sw_inport;
                }
 
@@ -673,7 +776,7 @@ static int __devinit rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                                rio_route_add_entry(port, rdev->rswitch,
                                                RIO_GLOBAL_TABLE,
                                                RIO_ANY_DESTID(port->sys_size),
-                                               port_num);
+                                               port_num, 0);
 
                                if (rio_enum_peer(net, port, hopcount + 1) < 0)
                                        return -1;
@@ -687,7 +790,8 @@ static int __devinit rio_enum_peer(struct rio_net *net, struct rio_mport *port,
                                                rio_route_add_entry(port, rdev->rswitch,
                                                                    RIO_GLOBAL_TABLE,
                                                                    destid,
-                                                                   port_num);
+                                                                   port_num,
+                                                                   0);
                                                rdev->rswitch->
                                                    route_table[destid] =
                                                    port_num;
@@ -778,17 +882,21 @@ rio_disc_peer(struct rio_net *net, struct rio_mport *port, u16 destid,
                                pr_debug(
                                    "RIO: scanning device on port %d\n",
                                    port_num);
+
+                               rio_lock_device(port, destid, hopcount, 1000);
+
                                for (ndestid = 0;
                                     ndestid < RIO_ANY_DESTID(port->sys_size);
                                     ndestid++) {
                                        rio_route_get_entry(port, rdev->rswitch,
                                                            RIO_GLOBAL_TABLE,
                                                            ndestid,
-                                                           &route_port);
+                                                           &route_port, 0);
                                        if (route_port == port_num)
                                                break;
                                }
 
+                               rio_unlock_device(port, destid, hopcount);
                                if (rio_disc_peer
                                    (net, port, ndestid, hopcount + 1) < 0)
                                        return -1;
@@ -889,7 +997,9 @@ static void rio_update_route_tables(struct rio_mport *port)
                                                rswitch->destid, rswitch->hopcount);
 
                                if (rswitch->add_entry) {
-                                       rio_route_add_entry(port, rswitch, RIO_GLOBAL_TABLE, destid, sport);
+                                       rio_route_add_entry(port, rswitch,
+                                               RIO_GLOBAL_TABLE, destid,
+                                               sport, 0);
                                        rswitch->route_table[destid] = sport;
                                }
                        }
@@ -963,15 +1073,22 @@ static void rio_build_route_tables(void)
        u8 sport;
 
        list_for_each_entry(rdev, &rio_devices, global_list)
-           if (rio_is_switch(rdev))
-               for (i = 0;
-                    i < RIO_MAX_ROUTE_ENTRIES(rdev->net->hport->sys_size);
-                    i++) {
-                       if (rio_route_get_entry
-                           (rdev->net->hport, rdev->rswitch, RIO_GLOBAL_TABLE,
-                            i, &sport) < 0)
-                               continue;
-                       rdev->rswitch->route_table[i] = sport;
+               if (rio_is_switch(rdev)) {
+                       rio_lock_device(rdev->net->hport, rdev->rswitch->destid,
+                                       rdev->rswitch->hopcount, 1000);
+                       for (i = 0;
+                            i < RIO_MAX_ROUTE_ENTRIES(rdev->net->hport->sys_size);
+                            i++) {
+                               if (rio_route_get_entry
+                                   (rdev->net->hport, rdev->rswitch,
+                                    RIO_GLOBAL_TABLE, i, &sport, 0) < 0)
+                                       continue;
+                               rdev->rswitch->route_table[i] = sport;
+                       }
+
+                       rio_unlock_device(rdev->net->hport,
+                                         rdev->rswitch->destid,
+                                         rdev->rswitch->hopcount);
                }
 }
 
@@ -1030,6 +1147,13 @@ int __devinit rio_disc_mport(struct rio_mport *mport)
                del_timer_sync(&rio_enum_timer);
 
                pr_debug("done\n");
+
+               /* Read DestID assigned by enumerator */
+               rio_local_read_config_32(mport, RIO_DID_CSR,
+                                        &mport->host_deviceid);
+               mport->host_deviceid = RIO_GET_DID(mport->sys_size,
+                                                  mport->host_deviceid);
+
                if (rio_disc_peer(net, mport, RIO_ANY_DESTID(mport->sys_size),
                                        0) < 0) {
                        printk(KERN_INFO