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rapidio: add switch locking during discovery
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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>
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Alexandre Bounine authored and Linus Torvalds committed May 27, 2010
1 parent 07590ff commit 818a04a
Showing 1 changed file with 144 additions and 20 deletions.
164 changes: 144 additions & 20 deletions drivers/rapidio/rio-scan.c
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Original file line number Diff line number Diff line change
Expand Up @@ -456,13 +456,88 @@ rio_sport_is_active(struct rio_mport *port, u16 destid, u8 hopcount, int sport)
return (result & PORT_N_ERR_STS_PORT_OK);
}

/**
* 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
Expand All @@ -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;
}

/**
Expand All @@ -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
Expand All @@ -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;
}

/**
Expand Down Expand Up @@ -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;
}

Expand All @@ -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;
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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;
}
}
Expand Down Expand Up @@ -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);
}
}

Expand Down Expand Up @@ -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
Expand Down

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