[PATCH 2/7] RapidIO: Add switch locking during discovery

[Alexandre Bounine <alexb@tundra.com>]

From: Alexandre Bounine <alexandre.bounine@idt.com>

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>
---

 rio-scan.c |   88 ++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 files changed, 79 insertions(+), 9 deletions(-)

diff -x '*.pj' -X dontdiff_2.6.32-rc5 -pNur w33r7a/drivers/rapidio/rio-scan.c w33r7b/drivers/rapidio/rio-scan.c
--- w33r7a/drivers/rapidio/rio-scan.c	2010-02-09 15:11:09.141972000 -0500
+++ w33r7b/drivers/rapidio/rio-scan.c	2010-02-10 16:13:56.382802000 -0500
@@ -750,6 +750,7 @@ rio_disc_peer(struct rio_net *net, struc
 	int num_ports;
 	struct rio_dev *rdev;
 	u16 ndestid;
+	u32 result;
 
 	/* Setup new RIO device */
 	if ((rdev = rio_setup_device(net, port, destid, hopcount, 0))) {
@@ -778,6 +779,27 @@ rio_disc_peer(struct rio_net *net, struc
 				pr_debug(
 				    "RIO: scanning device on port %d\n",
 				    port_num);
+
+				/* 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) {
+					/* Delay a bit */
+					mdelay(1);
+					/* 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);
+				}
+
 				for (ndestid = 0;
 				     ndestid < RIO_ANY_DESTID(port->sys_size);
 				     ndestid++) {
@@ -789,6 +811,19 @@ rio_disc_peer(struct rio_net *net, struc
 						break;
 				}
 
+				/* 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_info("RIO: badness when releasing " \
+						"host lock on %s\n",
+						rio_name(rdev));
+				}
+
 				if (rio_disc_peer
 				    (net, port, ndestid, hopcount + 1) < 0)
 					return -1;
@@ -958,17 +993,45 @@ static void rio_build_route_tables(void)
 	struct rio_dev *rdev;
 	int i;
 	u8 sport;
+	u32 result;
 
 	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)) {
+			/* Attempt to acquire device lock */
+			rio_write_config_32(rdev, RIO_HOST_DID_LOCK_CSR,
+					rdev->net->hport->host_deviceid);
+			rio_read_config_32(rdev,
+					RIO_HOST_DID_LOCK_CSR, &result);
+			while (result != rdev->net->hport->host_deviceid) {
+				/* Delay a bit */
+				mdelay(1);
+				/* Attempt to acquire device lock again */
+				rio_write_config_32(rdev, RIO_HOST_DID_LOCK_CSR,
+					rdev->net->hport->host_deviceid);
+				rio_read_config_32(rdev,
+					RIO_HOST_DID_LOCK_CSR, &result);
+			}
+
+			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;
+			}
+
+			/* Release device lock */
+			rio_write_config_32(rdev, RIO_HOST_DID_LOCK_CSR,
+					rdev->net->hport->host_deviceid);
+			rio_read_config_32(rdev,
+					RIO_HOST_DID_LOCK_CSR, &result);
+			if ((result & 0xffff) != 0xffff) {
+				pr_info("RIO: badness when releasing " \
+					"host lock on %s\n", rio_name(rdev));
+			}
+
 		}
 }
 
@@ -1027,6 +1090,13 @@ int __devinit rio_disc_mport(struct rio_
 		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

---

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