From 9edbc30b434f56258d03faac5daf37a555384db3 Mon Sep 17 00:00:00 2001 From: Alexandre Bounine Date: Wed, 3 Jul 2013 15:08:53 -0700 Subject: 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 Cc: Matt Porter Cc: Li Yang Cc: Kumar Gala Cc: Andre van Herk Cc: Micha Nelissen Cc: Stef van Os Cc: Jean Delvare Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/rapidio/rio.c | 176 +++++++++++++++++++++++++++++++++++++++++--------- 1 file changed, 145 insertions(+), 31 deletions(-) (limited to 'drivers/rapidio/rio.c') diff --git a/drivers/rapidio/rio.c b/drivers/rapidio/rio.c index b17d5218005e..5eb727cd0652 100644 --- a/drivers/rapidio/rio.c +++ b/drivers/rapidio/rio.c @@ -34,6 +34,7 @@ static LIST_HEAD(rio_devices); 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 @@ found: * 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 + * + * 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). * - * Assigns enumeration or discovery method 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; - 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; + pr_debug("RIO: %s for mport_id=%d\n", __func__, mport_id); - port->nscan = scan_ops; - rc = 0; + if ((mport_id != RIO_MPORT_ANY && mport_id >= RIO_MAX_MPORTS) || + !scan_ops) + return -EINVAL; - if (mport_id != RIO_MPORT_ANY) - break; + mutex_lock(&rio_mport_list_lock); + + /* + * 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 @@ EXPORT_SYMBOL_GPL(rio_register_scan); /** * 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 @@ static void disc_work_handler(struct work_struct *_work) 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 @@ int rio_init_mports(void) 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 @@ int rio_init_mports(void) * 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 @@ int rio_init_mports(void) 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 @@ __setup("riohdid=", rio_hdid_setup); 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 @@ int rio_register_mport(struct rio_mport *port) 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; } -- cgit v1.2.3