diff options
Diffstat (limited to 'drivers/firmware/arm_scmi/bus.c')
-rw-r--r-- | drivers/firmware/arm_scmi/bus.c | 157 |
1 files changed, 156 insertions, 1 deletions
diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c index bed566f58029..e63cc1194d43 100644 --- a/drivers/firmware/arm_scmi/bus.c +++ b/drivers/firmware/arm_scmi/bus.c @@ -9,6 +9,7 @@ #include <linux/types.h> #include <linux/module.h> +#include <linux/of.h> #include <linux/kernel.h> #include <linux/slab.h> #include <linux/device.h> @@ -20,6 +21,160 @@ EXPORT_SYMBOL_GPL(scmi_requested_devices_nh); static DEFINE_IDA(scmi_bus_id); +static DEFINE_IDR(scmi_requested_devices); +/* Protect access to scmi_requested_devices */ +static DEFINE_MUTEX(scmi_requested_devices_mtx); + +struct scmi_requested_dev { + const struct scmi_device_id *id_table; + struct list_head node; +}; + +/** + * scmi_protocol_device_request - Helper to request a device + * + * @id_table: A protocol/name pair descriptor for the device to be created. + * + * This helper let an SCMI driver request specific devices identified by the + * @id_table to be created for each active SCMI instance. + * + * The requested device name MUST NOT be already existent for any protocol; + * at first the freshly requested @id_table is annotated in the IDR table + * @scmi_requested_devices and then the requested device is advertised to any + * registered party via the @scmi_requested_devices_nh notification chain. + * + * Return: 0 on Success + */ +static int scmi_protocol_device_request(const struct scmi_device_id *id_table) +{ + int ret = 0; + unsigned int id = 0; + struct list_head *head, *phead = NULL; + struct scmi_requested_dev *rdev; + + pr_debug("Requesting SCMI device (%s) for protocol %x\n", + id_table->name, id_table->protocol_id); + + /* + * Search for the matching protocol rdev list and then search + * of any existent equally named device...fails if any duplicate found. + */ + mutex_lock(&scmi_requested_devices_mtx); + idr_for_each_entry(&scmi_requested_devices, head, id) { + if (!phead) { + /* A list found registered in the IDR is never empty */ + rdev = list_first_entry(head, struct scmi_requested_dev, + node); + if (rdev->id_table->protocol_id == + id_table->protocol_id) + phead = head; + } + list_for_each_entry(rdev, head, node) { + if (!strcmp(rdev->id_table->name, id_table->name)) { + pr_err("Ignoring duplicate request [%d] %s\n", + rdev->id_table->protocol_id, + rdev->id_table->name); + ret = -EINVAL; + goto out; + } + } + } + + /* + * No duplicate found for requested id_table, so let's create a new + * requested device entry for this new valid request. + */ + rdev = kzalloc(sizeof(*rdev), GFP_KERNEL); + if (!rdev) { + ret = -ENOMEM; + goto out; + } + rdev->id_table = id_table; + + /* + * Append the new requested device table descriptor to the head of the + * related protocol list, eventually creating such head if not already + * there. + */ + if (!phead) { + phead = kzalloc(sizeof(*phead), GFP_KERNEL); + if (!phead) { + kfree(rdev); + ret = -ENOMEM; + goto out; + } + INIT_LIST_HEAD(phead); + + ret = idr_alloc(&scmi_requested_devices, (void *)phead, + id_table->protocol_id, + id_table->protocol_id + 1, GFP_KERNEL); + if (ret != id_table->protocol_id) { + pr_err("Failed to save SCMI device - ret:%d\n", ret); + kfree(rdev); + kfree(phead); + ret = -EINVAL; + goto out; + } + ret = 0; + } + list_add(&rdev->node, phead); + +out: + mutex_unlock(&scmi_requested_devices_mtx); + + if (!ret) + blocking_notifier_call_chain(&scmi_requested_devices_nh, + SCMI_BUS_NOTIFY_DEVICE_REQUEST, + (void *)rdev->id_table); + + return ret; +} + +/** + * scmi_protocol_device_unrequest - Helper to unrequest a device + * + * @id_table: A protocol/name pair descriptor for the device to be unrequested. + * + * The unrequested device, described by the provided id_table, is at first + * removed from the IDR @scmi_requested_devices and then the removal is + * advertised to any registered party via the @scmi_requested_devices_nh + * notification chain. + */ +static void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table) +{ + struct list_head *phead; + + pr_debug("Unrequesting SCMI device (%s) for protocol %x\n", + id_table->name, id_table->protocol_id); + + mutex_lock(&scmi_requested_devices_mtx); + phead = idr_find(&scmi_requested_devices, id_table->protocol_id); + if (phead) { + struct scmi_requested_dev *victim, *tmp; + + list_for_each_entry_safe(victim, tmp, phead, node) { + if (!strcmp(victim->id_table->name, id_table->name)) { + list_del(&victim->node); + + mutex_unlock(&scmi_requested_devices_mtx); + blocking_notifier_call_chain(&scmi_requested_devices_nh, + SCMI_BUS_NOTIFY_DEVICE_UNREQUEST, + (void *)victim->id_table); + kfree(victim); + mutex_lock(&scmi_requested_devices_mtx); + break; + } + } + + if (list_empty(phead)) { + idr_remove(&scmi_requested_devices, + id_table->protocol_id); + kfree(phead); + } + } + mutex_unlock(&scmi_requested_devices_mtx); +} + static const struct scmi_device_id * scmi_dev_match_id(struct scmi_device *scmi_dev, struct scmi_driver *scmi_drv) { @@ -124,7 +279,7 @@ int scmi_driver_register(struct scmi_driver *driver, struct module *owner, retval = driver_register(&driver->driver); if (!retval) - pr_debug("registered new scmi driver %s\n", driver->name); + pr_debug("Registered new scmi driver %s\n", driver->name); return retval; } |