#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+#include <linux/atomic.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/of.h>
struct list_head node;
};
+/* Track globally the creation of SCMI SystemPower related devices */
+static atomic_t scmi_syspower_registered = ATOMIC_INIT(0);
+
/**
* scmi_protocol_device_request - Helper to request a device
*
struct scmi_device_id *id_table = data;
return sdev->protocol_id == id_table->protocol_id &&
- !strcmp(sdev->name, id_table->name);
+ (id_table->name && !strcmp(sdev->name, id_table->name));
}
-struct scmi_device *scmi_child_dev_find(struct device *parent,
- int prot_id, const char *name)
+static struct scmi_device *scmi_child_dev_find(struct device *parent,
+ int prot_id, const char *name)
{
struct scmi_device_id id_table;
struct device *dev;
kfree(to_scmi_dev(dev));
}
-struct scmi_device *
-scmi_device_create(struct device_node *np, struct device *parent, int protocol,
- const char *name)
+static void __scmi_device_destroy(struct scmi_device *scmi_dev)
+{
+ pr_debug("(%s) Destroying SCMI device '%s' for protocol 0x%x (%s)\n",
+ of_node_full_name(scmi_dev->dev.parent->of_node),
+ dev_name(&scmi_dev->dev), scmi_dev->protocol_id,
+ scmi_dev->name);
+
+ if (scmi_dev->protocol_id == SCMI_PROTOCOL_SYSTEM)
+ atomic_set(&scmi_syspower_registered, 0);
+
+ kfree_const(scmi_dev->name);
+ ida_free(&scmi_bus_id, scmi_dev->id);
+ device_unregister(&scmi_dev->dev);
+}
+
+static struct scmi_device *
+__scmi_device_create(struct device_node *np, struct device *parent,
+ int protocol, const char *name)
{
int id, retval;
struct scmi_device *scmi_dev;
+ /*
+ * If the same protocol/name device already exist under the same parent
+ * (i.e. SCMI instance) just return the existent device.
+ * This avoids any race between the SCMI driver, creating devices for
+ * each DT defined protocol at probe time, and the concurrent
+ * registration of SCMI drivers.
+ */
+ scmi_dev = scmi_child_dev_find(parent, protocol, name);
+ if (scmi_dev)
+ return scmi_dev;
+
+ /*
+ * Ignore any possible subsequent failures while creating the device
+ * since we are doomed anyway at that point; not using a mutex which
+ * spans across this whole function to keep things simple and to avoid
+ * to serialize all the __scmi_device_create calls across possibly
+ * different SCMI server instances (parent)
+ */
+ if (protocol == SCMI_PROTOCOL_SYSTEM &&
+ atomic_cmpxchg(&scmi_syspower_registered, 0, 1)) {
+ dev_warn(parent,
+ "SCMI SystemPower protocol device must be unique !\n");
+ return NULL;
+ }
+
scmi_dev = kzalloc(sizeof(*scmi_dev), GFP_KERNEL);
if (!scmi_dev)
return NULL;
if (retval)
goto put_dev;
+ pr_debug("(%s) Created SCMI device '%s' for protocol 0x%x (%s)\n",
+ of_node_full_name(parent->of_node),
+ dev_name(&scmi_dev->dev), protocol, name);
+
return scmi_dev;
put_dev:
kfree_const(scmi_dev->name);
return NULL;
}
-void scmi_device_destroy(struct scmi_device *scmi_dev)
+/**
+ * scmi_device_create - A method to create one or more SCMI devices
+ *
+ * @np: A reference to the device node to use for the new device(s)
+ * @parent: The parent device to use identifying a specific SCMI instance
+ * @protocol: The SCMI protocol to be associated with this device
+ * @name: The requested-name of the device to be created; this is optional
+ * and if no @name is provided, all the devices currently known to
+ * be requested on the SCMI bus for @protocol will be created.
+ *
+ * This method can be invoked to create a single well-defined device (like
+ * a transport device or a device requested by an SCMI driver loaded after
+ * the core SCMI stack has been probed), or to create all the devices currently
+ * known to have been requested by the loaded SCMI drivers for a specific
+ * protocol (typically during SCMI core protocol enumeration at probe time).
+ *
+ * Return: The created device (or one of them if @name was NOT provided and
+ * multiple devices were created) or NULL if no device was created;
+ * note that NULL indicates an error ONLY in case a specific @name
+ * was provided: when @name param was not provided, a number of devices
+ * could have been potentially created for a whole protocol, unless no
+ * device was found to have been requested for that specific protocol.
+ */
+struct scmi_device *scmi_device_create(struct device_node *np,
+ struct device *parent, int protocol,
+ const char *name)
{
- kfree_const(scmi_dev->name);
- ida_free(&scmi_bus_id, scmi_dev->id);
- device_unregister(&scmi_dev->dev);
+ struct list_head *phead;
+ struct scmi_requested_dev *rdev;
+ struct scmi_device *scmi_dev = NULL;
+
+ if (name)
+ return __scmi_device_create(np, parent, protocol, name);
+
+ mutex_lock(&scmi_requested_devices_mtx);
+ phead = idr_find(&scmi_requested_devices, protocol);
+ /* Nothing to do. */
+ if (!phead) {
+ mutex_unlock(&scmi_requested_devices_mtx);
+ return scmi_dev;
+ }
+
+ /* Walk the list of requested devices for protocol and create them */
+ list_for_each_entry(rdev, phead, node) {
+ struct scmi_device *sdev;
+
+ sdev = __scmi_device_create(np, parent,
+ rdev->id_table->protocol_id,
+ rdev->id_table->name);
+ /* Report errors and carry on... */
+ if (sdev)
+ scmi_dev = sdev;
+ else
+ pr_err("(%s) Failed to create device for protocol 0x%x (%s)\n",
+ of_node_full_name(parent->of_node),
+ rdev->id_table->protocol_id,
+ rdev->id_table->name);
+ }
+ mutex_unlock(&scmi_requested_devices_mtx);
+
+ return scmi_dev;
}
+EXPORT_SYMBOL_GPL(scmi_device_create);
+
+void scmi_device_destroy(struct device *parent, int protocol, const char *name)
+{
+ struct scmi_device *scmi_dev;
+
+ scmi_dev = scmi_child_dev_find(parent, protocol, name);
+ if (scmi_dev)
+ __scmi_device_destroy(scmi_dev);
+}
+EXPORT_SYMBOL_GPL(scmi_device_destroy);
static int __scmi_devices_unregister(struct device *dev, void *data)
{
struct scmi_device *scmi_dev = to_scmi_dev(dev);
- scmi_device_destroy(scmi_dev);
+ __scmi_device_destroy(scmi_dev);
return 0;
}
void __exit scmi_bus_exit(void)
{
+ /*
+ * Destroy all remaining devices: just in case the drivers were
+ * manually unbound and at first and then the modules unloaded.
+ */
scmi_devices_unregister();
bus_unregister(&scmi_bus_type);
ida_destroy(&scmi_bus_id);
projects / linux-2.6-microblaze.git / commitdiff