STRUCT WIMAX_DEV(9)                      Linux Networking                     STRUCT WIMAX_DEV(9)



NAME
       struct_wimax_dev - Generic WiMAX device

SYNOPSIS
       struct wimax_dev {
         struct net_device * net_dev;
         struct list_head id_table_node;
         struct mutex mutex;
         struct mutex mutex_reset;
         enum wimax_st state;
         int (* op_msg_from_user) (struct wimax_dev *wimax_dev,const char *,const void *, size_t,const struct genl_info *info);
         int (* op_rfkill_sw_toggle) (struct wimax_dev *wimax_dev,enum wimax_rf_state);
         int (* op_reset) (struct wimax_dev *wimax_dev);
         struct rfkill * rfkill;
         unsigned int rf_hw;
         unsigned int rf_sw;
         char name[32];
         struct dentry * debugfs_dentry;
       };

MEMBERS
       net_dev
           [fill] Pointer to the struct net_device this WiMAX device implements.

       id_table_node
           [private] link to the list of wimax devices kept by id-table.c. Protected by it's own
           spinlock.

       mutex
           [private] Serializes all concurrent access and execution of operations.

       mutex_reset
           [private] Serializes reset operations. Needs to be a different mutex because as part
           of the reset operation, the driver has to call back into the stack to do things such
           as state change, that require wimax_dev->mutex.

       state
           [private] Current state of the WiMAX device.

       op_msg_from_user
           [fill] Driver-specific operation to handle a raw message from user space to the
           driver. The driver can send messages to user space using with wimax_msg_to_user.

       op_rfkill_sw_toggle
           [fill] Driver-specific operation to act on userspace (or any other agent) requesting
           the WiMAX device to change the RF Kill software switch (WIMAX_RF_ON or WIMAX_RF_OFF).
           If such hardware support is not present, it is assumed the radio cannot be switched
           off and it is always on (and the stack will error out when trying to switch it off).
           In such case, this function pointer can be left as NULL.

       op_reset
           [fill] Driver specific operation to reset the device. This operation should always
           attempt first a warm reset that does not disconnect the device from the bus and return
           0. If that fails, it should resort to some sort of cold or bus reset (even if it
           implies a bus disconnection and device disappearance). In that case, -ENODEV should be
           returned to indicate the device is gone. This operation has to be synchronous, and
           return only when the reset is complete. In case of having had to resort to bus/cold
           reset implying a device disconnection, the call is allowed to return immediately.

       rfkill
           [private] integration into the RF-Kill infrastructure.

       rf_hw
           [private] State of the hardware radio switch (OFF/ON)

       rf_sw
           [private] State of the software radio switch (OFF/ON)

       name[32]
           [fill] A way to identify this device. We need to register a name with many subsystems
           (rfkill, workqueue creation, etc). We can't use the network device name as that might
           change and in some instances we don't know it yet (until we don't call
           register_netdev). So we generate an unique one using the driver name and device bus
           id, place it here and use it across the board. Recommended naming:
           DRIVERNAME-BUSNAME:BUSID (dev->bus->name, dev->bus_id).

       debugfs_dentry
           [private] Used to hook up a debugfs entry. This shows up in the debugfs root as
           wimax\:DEVICENAME.

NOTE
       wimax_dev->mutex is NOT locked when this op is being called; however,
       wimax_dev->mutex_reset IS locked to ensure serialization of calls to wimax_reset. See
       wimax_reset's documentation.

DESCRIPTION
       This structure defines a common interface to access all WiMAX devices from different
       vendors and provides a common API as well as a free-form device-specific messaging
       channel.

       Usage: 1. Embed a struct wimax_dev at *the beginning* the network device structure so that
       netdev_priv points to it.

       2.  memset it to zero

       3. Initialize with wimax_dev_init. This will leave the WiMAX device in the __WIMAX_ST_NULL
       state.

       4. Fill all the fields marked with [fill]; once called wimax_dev_add, those fields CANNOT
       be modified.

       5. Call wimax_dev_add *after* registering the network device. This will leave the WiMAX
       device in the WIMAX_ST_DOWN state. Protect the driver's net_device->open against
       succeeding if the wimax device state is lower than WIMAX_ST_DOWN.

       6. Select when the device is going to be turned on/initialized; for example, it could be
       initialized on 'ifconfig up' (when the netdev op 'open' is called on the driver).

       When the device is initialized (at `ifconfig up` time, or right after calling
       wimax_dev_add from _probe, make sure the following steps are taken

       a. Move the device to WIMAX_ST_UNINITIALIZED. This is needed so some API calls that
       shouldn't work until the device is ready can be blocked.

       b. Initialize the device. Make sure to turn the SW radio switch off and move the device to
       state WIMAX_ST_RADIO_OFF when done. When just initialized, a device should be left in
       RADIO OFF state until user space devices to turn it on.

       c. Query the device for the state of the hardware rfkill switch and call
       wimax_rfkill_report_hw and wimax_rfkill_report_sw as needed. See below.

       wimax_dev_rm undoes before unregistering the network device. Once wimax_dev_add is called,
       the driver can get called on the wimax_dev->op_* function pointers

       CONCURRENCY:

       The stack provides a mutex for each device that will disallow API calls happening
       concurrently; thus, op calls into the driver through the wimax_dev->op*() function
       pointers will always be serialized and *never* concurrent.

       For locking, take wimax_dev->mutex is taken; (most) operations in the API have to check
       for wimax_dev_is_ready to return 0 before continuing (this is done internally).

       REFERENCE COUNTING:

       The WiMAX device is reference counted by the associated network device. The only operation
       that can be used to reference the device is wimax_dev_get_by_genl_info, and the reference
       it acquires has to be released with dev_put(wimax_dev->net_dev).

       RFKILL:

       At startup, both HW and SW radio switchess are assumed to be off.

       At initialization time [after calling wimax_dev_add], have the driver query the device for
       the status of the software and hardware RF kill switches and call wimax_report_rfkill_hw
       and wimax_rfkill_report_sw to indicate their state. If any is missing, just call it to
       indicate it is ON (radio always on).

       Whenever the driver detects a change in the state of the RF kill switches, it should call
       wimax_report_rfkill_hw or wimax_report_rfkill_sw to report it to the stack.

COPYRIGHT
Kernel Hackers Manual 4.8.                 January 2017                       STRUCT WIMAX_DEV(9)