rapidio: update enumerator registration mechanism
Update enumeration/discovery method registration mechanism to allow
loading enumeration/discovery methods before all mports are registered.
Existing statically linked RapidIO subsystem expects that all available
RapidIO mport devices are initialized and registered before the
enumeration/discovery method is registered. Switching to loadable mport
device drivers creates situation when mport device driver can be loaded
after enumeration/discovery method is attached (e.g., loadable mport
driver in a system with statically linked RapidIO core and enumerator).
This also will happen in a system with hot-pluggable RapidIO controllers.
To remove the dependency on the initialization/registration order this
patch introduces enumeration/discovery registration mechanism that
supports arbitrary registration order of mports and enumerator/discovery
methods.
The following registration rules are implemented:
- only one enumeration/discovery method can be registered for given mport ID
(including RIO_MPORT_ANY);
- when new enumeration/discovery methods tries to attach to the registered mport
device, method with matching mport ID will replace a default method previously
registered for given mport (if any);
- enumeration/discovery method with target ID=RIO_MPORT_ANY will be attached
only to mports that do not have another enumerator attached to them;
- when new mport device is registered with RapidIO subsystem, registration
routine searches for the enumeration/discovery method with the best matching
mport ID;
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Li Yang <leoli@freescale.com>
Cc: Kumar Gala <galak@kernel.crashing.org>
Cc: Andre van Herk <andre.van.herk@Prodrive.nl>
Cc: Micha Nelissen <micha.nelissen@Prodrive.nl>
Cc: Stef van Os <stef.van.os@Prodrive.nl>
Cc: Jean Delvare <jdelvare@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/rapidio/rio.c b/drivers/rapidio/rio.c
index b17d521..5eb727c 100644
--- a/drivers/rapidio/rio.c
+++ b/drivers/rapidio/rio.c
@@ -34,6 +34,7 @@
static DEFINE_SPINLOCK(rio_global_list_lock);
static LIST_HEAD(rio_mports);
+static LIST_HEAD(rio_scans);
static DEFINE_MUTEX(rio_mport_list_lock);
static unsigned char next_portid;
static DEFINE_SPINLOCK(rio_mmap_lock);
@@ -1602,34 +1603,73 @@
* rio_register_scan - enumeration/discovery method registration interface
* @mport_id: mport device ID for which fabric scan routine has to be set
* (RIO_MPORT_ANY = set for all available mports)
- * @scan_ops: enumeration/discovery control structure
+ * @scan_ops: enumeration/discovery operations structure
*
- * Assigns enumeration or discovery method to the specified mport device (or all
- * available mports if RIO_MPORT_ANY is specified).
+ * Registers enumeration/discovery operations with RapidIO subsystem and
+ * attaches it to the specified mport device (or all available mports
+ * if RIO_MPORT_ANY is specified).
+ *
* Returns error if the mport already has an enumerator attached to it.
- * In case of RIO_MPORT_ANY ignores ports with valid scan routines and returns
- * an error if was unable to find at least one available mport.
+ * In case of RIO_MPORT_ANY skips mports with valid scan routines (no error).
*/
int rio_register_scan(int mport_id, struct rio_scan *scan_ops)
{
struct rio_mport *port;
- int rc = -EBUSY;
+ struct rio_scan_node *scan;
+ int rc = 0;
+
+ pr_debug("RIO: %s for mport_id=%d\n", __func__, mport_id);
+
+ if ((mport_id != RIO_MPORT_ANY && mport_id >= RIO_MAX_MPORTS) ||
+ !scan_ops)
+ return -EINVAL;
mutex_lock(&rio_mport_list_lock);
- list_for_each_entry(port, &rio_mports, node) {
- if (port->id == mport_id || mport_id == RIO_MPORT_ANY) {
- if (port->nscan && mport_id == RIO_MPORT_ANY)
- continue;
- else if (port->nscan)
- break;
- port->nscan = scan_ops;
- rc = 0;
-
- if (mport_id != RIO_MPORT_ANY)
- break;
+ /*
+ * Check if there is another enumerator already registered for
+ * the same mport ID (including RIO_MPORT_ANY). Multiple enumerators
+ * for the same mport ID are not supported.
+ */
+ list_for_each_entry(scan, &rio_scans, node) {
+ if (scan->mport_id == mport_id) {
+ rc = -EBUSY;
+ goto err_out;
}
}
+
+ /*
+ * Allocate and initialize new scan registration node.
+ */
+ scan = kzalloc(sizeof(*scan), GFP_KERNEL);
+ if (!scan) {
+ rc = -ENOMEM;
+ goto err_out;
+ }
+
+ scan->mport_id = mport_id;
+ scan->ops = scan_ops;
+
+ /*
+ * Traverse the list of registered mports to attach this new scan.
+ *
+ * The new scan with matching mport ID overrides any previously attached
+ * scan assuming that old scan (if any) is the default one (based on the
+ * enumerator registration check above).
+ * If the new scan is the global one, it will be attached only to mports
+ * that do not have their own individual operations already attached.
+ */
+ list_for_each_entry(port, &rio_mports, node) {
+ if (port->id == mport_id) {
+ port->nscan = scan_ops;
+ break;
+ } else if (mport_id == RIO_MPORT_ANY && !port->nscan)
+ port->nscan = scan_ops;
+ }
+
+ list_add_tail(&scan->node, &rio_scans);
+
+err_out:
mutex_unlock(&rio_mport_list_lock);
return rc;
@@ -1639,30 +1679,81 @@
/**
* rio_unregister_scan - removes enumeration/discovery method from mport
* @mport_id: mport device ID for which fabric scan routine has to be
- * unregistered (RIO_MPORT_ANY = set for all available mports)
+ * unregistered (RIO_MPORT_ANY = apply to all mports that use
+ * the specified scan_ops)
+ * @scan_ops: enumeration/discovery operations structure
*
* Removes enumeration or discovery method assigned to the specified mport
- * device (or all available mports if RIO_MPORT_ANY is specified).
+ * device. If RIO_MPORT_ANY is specified, removes the specified operations from
+ * all mports that have them attached.
*/
-int rio_unregister_scan(int mport_id)
+int rio_unregister_scan(int mport_id, struct rio_scan *scan_ops)
{
struct rio_mport *port;
+ struct rio_scan_node *scan;
+
+ pr_debug("RIO: %s for mport_id=%d\n", __func__, mport_id);
+
+ if (mport_id != RIO_MPORT_ANY && mport_id >= RIO_MAX_MPORTS)
+ return -EINVAL;
mutex_lock(&rio_mport_list_lock);
- list_for_each_entry(port, &rio_mports, node) {
- if (port->id == mport_id || mport_id == RIO_MPORT_ANY) {
- if (port->nscan)
- port->nscan = NULL;
- if (mport_id != RIO_MPORT_ANY)
- break;
+
+ list_for_each_entry(port, &rio_mports, node)
+ if (port->id == mport_id ||
+ (mport_id == RIO_MPORT_ANY && port->nscan == scan_ops))
+ port->nscan = NULL;
+
+ list_for_each_entry(scan, &rio_scans, node)
+ if (scan->mport_id == mport_id) {
+ list_del(&scan->node);
+ kfree(scan);
}
- }
+
mutex_unlock(&rio_mport_list_lock);
return 0;
}
EXPORT_SYMBOL_GPL(rio_unregister_scan);
+/**
+ * rio_mport_scan - execute enumeration/discovery on the specified mport
+ * @mport_id: number (ID) of mport device
+ */
+int rio_mport_scan(int mport_id)
+{
+ struct rio_mport *port = NULL;
+ int rc;
+
+ mutex_lock(&rio_mport_list_lock);
+ list_for_each_entry(port, &rio_mports, node) {
+ if (port->id == mport_id)
+ goto found;
+ }
+ mutex_unlock(&rio_mport_list_lock);
+ return -ENODEV;
+found:
+ if (!port->nscan) {
+ mutex_unlock(&rio_mport_list_lock);
+ return -EINVAL;
+ }
+
+ if (!try_module_get(port->nscan->owner)) {
+ mutex_unlock(&rio_mport_list_lock);
+ return -ENODEV;
+ }
+
+ mutex_unlock(&rio_mport_list_lock);
+
+ if (port->host_deviceid >= 0)
+ rc = port->nscan->enumerate(port, 0);
+ else
+ rc = port->nscan->discover(port, RIO_SCAN_ENUM_NO_WAIT);
+
+ module_put(port->nscan->owner);
+ return rc;
+}
+
static void rio_fixup_device(struct rio_dev *dev)
{
}
@@ -1691,7 +1782,10 @@
work = container_of(_work, struct rio_disc_work, work);
pr_debug("RIO: discovery work for mport %d %s\n",
work->mport->id, work->mport->name);
- work->mport->nscan->discover(work->mport, 0);
+ if (try_module_get(work->mport->nscan->owner)) {
+ work->mport->nscan->discover(work->mport, 0);
+ module_put(work->mport->nscan->owner);
+ }
}
int rio_init_mports(void)
@@ -1710,8 +1804,10 @@
mutex_lock(&rio_mport_list_lock);
list_for_each_entry(port, &rio_mports, node) {
if (port->host_deviceid >= 0) {
- if (port->nscan)
+ if (port->nscan && try_module_get(port->nscan->owner)) {
port->nscan->enumerate(port, 0);
+ module_put(port->nscan->owner);
+ }
} else
n++;
}
@@ -1725,7 +1821,7 @@
* for each of them. If the code below fails to allocate needed
* resources, exit without error to keep results of enumeration
* process (if any).
- * TODO: Implement restart of dicovery process for all or
+ * TODO: Implement restart of discovery process for all or
* individual discovering mports.
*/
rio_wq = alloc_workqueue("riodisc", 0, 0);
@@ -1751,9 +1847,9 @@
n++;
}
}
- mutex_unlock(&rio_mport_list_lock);
flush_workqueue(rio_wq);
+ mutex_unlock(&rio_mport_list_lock);
pr_debug("RIO: destroy discovery workqueue\n");
destroy_workqueue(rio_wq);
kfree(work);
@@ -1784,6 +1880,8 @@
int rio_register_mport(struct rio_mport *port)
{
+ struct rio_scan_node *scan = NULL;
+
if (next_portid >= RIO_MAX_MPORTS) {
pr_err("RIO: reached specified max number of mports\n");
return 1;
@@ -1792,9 +1890,25 @@
port->id = next_portid++;
port->host_deviceid = rio_get_hdid(port->id);
port->nscan = NULL;
+
mutex_lock(&rio_mport_list_lock);
list_add_tail(&port->node, &rio_mports);
+
+ /*
+ * Check if there are any registered enumeration/discovery operations
+ * that have to be attached to the added mport.
+ */
+ list_for_each_entry(scan, &rio_scans, node) {
+ if (port->id == scan->mport_id ||
+ scan->mport_id == RIO_MPORT_ANY) {
+ port->nscan = scan->ops;
+ if (port->id == scan->mport_id)
+ break;
+ }
+ }
mutex_unlock(&rio_mport_list_lock);
+
+ pr_debug("RIO: %s %s id=%d\n", __func__, port->name, port->id);
return 0;
}