Intel Wi-Fi Init Path
======================================


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        Topics in this section,

                * :ref:`Learnings in this section <FreebsdDeviceDriver_wireless_fdd_wi-fi_chipset_wi-fi_init_path_step1>`

                * :ref:`Version Info <FreebsdDeviceDriver_wireless_fdd_wi-fi_chipset_wi-fi_init_path_step3>`

	                * :ref:`Init path <FreebsdDeviceDriver_wireless_fdd_wi-fi_chipset_wi-fi_init_path_step37>`





.. _FreebsdDeviceDriver_wireless_fdd_wi-fi_chipset_wi-fi_init_path_step1:
  
.. tab-set::

   .. tab-item:: Learnings in this section

        * In this section, you are going to learn

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                * Wi-Fi init path


.. _FreebsdDeviceDriver_wireless_fdd_wi-fi_chipset_wi-fi_init_path_step3:

.. tab-set::
 
    .. tab-item:: Version Info

        =============================== =======================================
        #                               Version
        =============================== =======================================
        Freebsd                         14.1.0
	wpa_supplicant                  2.10
        =============================== =======================================



.. _FreebsdDeviceDriver_wireless_fdd_wi-fi_chipset_wi-fi_init_path_step37:

.. tab-set::

   .. tab-item:: Init path

	.. tab-set::

	   .. tab-item:: Device structure

		* Abstract representation of a device

		* Defined in /usr/src/stand/kshim/bsd_kernel.h

		.. code-block:: c

			typedef struct device *device_t;

			struct device {
				TAILQ_HEAD(device_list, device) dev_children;
				TAILQ_ENTRY(device) dev_link;

				struct device *dev_parent;
				const struct module_data *dev_module;
				void   *dev_sc;
				void   *dev_aux;
				driver_filter_t *dev_irq_filter;
				driver_intr_t *dev_irq_fn;
				void   *dev_irq_arg;

				uint16_t dev_unit;

				char	dev_nameunit[64];
				char	dev_desc[64];

				uint8_t	dev_res_alloc:1;
				uint8_t	dev_quiet:1;
				uint8_t	dev_softc_set:1;
				uint8_t	dev_softc_alloc:1;
				uint8_t	dev_attached:1;
				uint8_t	dev_fixed_class:1;
				uint8_t	dev_unit_manual:1;
			}; 

		* The device object represents a piece of hardware attached to the system.

		* Ex: expansion card, the bus which that card is plugged into, disk drives attached to the expansion card, …

		* The system defines one device, - root_bus.

		* All other devices are created dynamically during auto configuration.

		* device_probe_and_attach() 

			* initialise a device

			* This  function is called during autoconfiguration to initialise the devices in the system.

			* For each device, the  DEVICE_PROBE  method  of each  suitable  driver is called and if a probe succeeds, a description of the device is printed and the DEVICE_ATTACH method is called

		* DEVICE_PROBE 

			* Probe for device existence

			* Method should probe to see if the device is present.

		* DEVICE_ATTACH

			* Attach a device

			* Attach  a device to the system after the DEVICE_PROBE() method has been called and has indicated that the device exists

	.. tab-set::

	   .. tab-item:: Driver structure

		* structure describing a device driver

		* Defined in /usr/src/stand/kshim/bsd_kernel.h

		.. code-block:: c

			test:~$ typedef struct driver driver_t;

			struct driver {
				const char * name;
				const struct device_method *methods;
				uint32_t size;
			};

		* Driver is registered with the system by the DRIVER_MODULE macro

		* Each driver will implement one or more sets of methods called interfaces

		* Ex: methods from Device interface, methods from Bus interface

	.. tab-set::

	    .. tab-item:: Communication

		1. wlan(net80211 driver)

		2. linuxkpi(linux kernel functions and drivers to work on FreeBSD) 

		3. iwlwifi(enter intel driver)

	.. tab-set::

	    .. tab-item:: Init Path
	
		.. code-block:: shell

			device_probe_and_attach()

				device_probe()

					pci_probe() // pci controller

				device_attach()

					pci_attach() // pci controller