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>

5 files changed, 64 insertions, 51 deletions

diff --git a/arch/powerpc/sysdev/fsl_rio.c b/arch/powerpc/sysdev/fsl_rio.c
index ed2ec7154917..9725369d432a 100644
--- a/arch/powerpc/sysdev/fsl_rio.c
+++ b/arch/powerpc/sysdev/fsl_rio.c
@@ -50,6 +50,7 @@
 #define RIO_ATMU_REGS_OFFSET    0x10c00
 #define RIO_P_MSG_REGS_OFFSET   0x11000
 #define RIO_S_MSG_REGS_OFFSET   0x13000
+#define RIO_GCCSR               0x13c
 #define RIO_ESCSR               0x158
 #define RIO_CCSR                0x15c
 #define RIO_LTLEDCSR            0x0608
@@ -1471,6 +1472,7 @@ int fsl_rio_setup(struct platform_device *dev)
         port->host_deviceid = fsl_rio_get_hdid(port->id);
 
         port->priv = priv;
+        port->phys_efptr = 0x100;
         rio_register_mport(port);
 
         priv->regs_win = ioremap(regs.start, regs.end - regs.start + 1);
@@ -1518,6 +1520,12 @@ int fsl_rio_setup(struct platform_device *dev)
         dev_info(&dev->dev, "RapidIO Common Transport System size: %d\n",
                         port->sys_size ? 65536 : 256);
 
+        if (port->host_deviceid >= 0)
+                out_be32(priv->regs_win + RIO_GCCSR, RIO_PORT_GEN_HOST |
+                        RIO_PORT_GEN_MASTER | RIO_PORT_GEN_DISCOVERED);
+        else
+                out_be32(priv->regs_win + RIO_GCCSR, 0x00000000);
+
         priv->atmu_regs = (struct rio_atmu_regs *)(priv->regs_win
                                         + RIO_ATMU_REGS_OFFSET);
         priv->maint_atmu_regs = priv->atmu_regs + 1;
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;
+                        }
+                }