2 # Copyright (c) 1998-2004 Doug Rabson
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32 * @defgroup DEVICE device - KObj methods for all device drivers
33 * @brief A basic set of methods required for all device drivers.
35 * The device interface is used to match devices to drivers during
36 * autoconfiguration and provides methods to allow drivers to handle
37 * system-wide events such as suspend, resume or shutdown.
42 # Needed for timestamping device probe/attach calls
44 #include <sys/tslog.h>
48 # Default implementations of some methods.
51 static int null_shutdown(device_t dev)
56 static int null_suspend(device_t dev)
61 static int null_resume(device_t dev)
66 static int null_quiesce(device_t dev)
71 static void * null_register(device_t dev)
78 * @brief Probe to see if a device matches a driver.
80 * Users should not call this method directly. Normally, this
81 * is called via device_probe_and_attach() to select a driver
82 * calling the DEVICE_PROBE() of all candidate drivers and attach
83 * the winning driver (if any) to the device.
85 * This function is used to match devices to device drivers.
86 * Typically, the driver will examine the device to see if
87 * it is suitable for this driver. This might include checking
88 * the values of various device instance variables or reading
91 * In some cases, there may be more than one driver available
92 * which can be used for a device (for instance there might
93 * be a generic driver which works for a set of many types of
94 * device and a more specific driver which works for a subset
95 * of devices). Because of this, a driver should not assume
96 * that it will be the driver that attaches to the device even
97 * if it returns a success status from DEVICE_PROBE(). In particular,
98 * a driver must free any resources which it allocated during
99 * the probe before returning. The return value of DEVICE_PROBE()
100 * is used to elect which driver is used - the driver which returns
101 * the largest non-error value wins the election and attaches to
102 * the device. Common non-error values are described in the
103 * DEVICE_PROBE(9) manual page.
105 * If a driver matches the hardware, it should set the device
106 * description string using device_set_desc() or
107 * device_set_desc_copy(). This string is used to generate an
108 * informative message when DEVICE_ATTACH() is called.
110 * As a special case, if a driver returns zero, the driver election
111 * is cut short and that driver will attach to the device
112 * immediately. This should rarely be used.
114 * For example, a probe method for a PCI device driver might look
119 * foo_probe(device_t dev)
121 * if (pci_get_vendor(dev) == FOOVENDOR &&
122 * pci_get_device(dev) == FOODEVICE) {
123 * device_set_desc(dev, "Foo device");
124 * return (BUS_PROBE_DEFAULT);
130 * To include this method in a device driver, use a line like this
131 * in the driver's method list:
134 * KOBJMETHOD(device_probe, foo_probe)
137 * @param dev the device to probe
139 * @retval 0 if this is the only possible driver for this
141 * @retval negative if the driver can match this device - the
142 * least negative value is used to select the
144 * @retval ENXIO if the driver does not match the device
145 * @retval positive if some kind of error was detected during
146 * the probe, a regular unix error code should
147 * be returned to indicate the type of error
148 * @see DEVICE_ATTACH(), pci_get_vendor(), pci_get_device()
151 TSENTER2(device_get_name(dev));
154 TSEXIT2(device_get_name(dev));
161 * @brief Allow a device driver to detect devices not otherwise enumerated.
163 * The DEVICE_IDENTIFY() method is used by some drivers (e.g. the ISA
164 * bus driver) to help populate the bus device with a useful set of
165 * child devices, normally by calling the BUS_ADD_CHILD() method of
166 * the parent device. For instance, the ISA bus driver uses several
167 * special drivers, including the isahint driver and the pnp driver to
168 * create child devices based on configuration hints and PnP bus
169 * probes respectively.
171 * Many bus drivers which support true plug-and-play do not need to
172 * use this method at all since child devices can be discovered
173 * automatically without help from child drivers.
175 * To include this method in a device driver, use a line like this
176 * in the driver's method list:
179 * KOBJMETHOD(device_identify, foo_identify)
182 * @param driver the driver whose identify method is being called
183 * @param parent the parent device to use when adding new children
185 STATICMETHOD void identify {
191 * @brief Attach a device to a device driver
193 * Normally only called via device_probe_and_attach(), this is called
194 * when a driver has succeeded in probing against a device.
195 * This method should initialise the hardware and allocate other
196 * system resources (e.g. devfs entries) as required.
198 * To include this method in a device driver, use a line like this
199 * in the driver's method list:
202 * KOBJMETHOD(device_attach, foo_attach)
205 * @param dev the device to probe
208 * @retval non-zero if some kind of error was detected during
209 * the attach, a regular unix error code should
210 * be returned to indicate the type of error
211 * @see DEVICE_PROBE()
214 TSENTER2(device_get_name(dev));
217 TSEXIT2(device_get_name(dev));
224 * @brief Detach a driver from a device.
226 * This can be called if the user is replacing the
227 * driver software or if a device is about to be physically removed
228 * from the system (e.g. for removable hardware such as USB or PCCARD).
230 * To include this method in a device driver, use a line like this
231 * in the driver's method list:
234 * KOBJMETHOD(device_detach, foo_detach)
237 * @param dev the device to detach
240 * @retval non-zero the detach could not be performed, e.g. if the
241 * driver does not support detaching.
243 * @see DEVICE_ATTACH()
250 * @brief Called during system shutdown.
252 * This method allows drivers to detect when the system is being shut down.
253 * Some drivers need to use this to place their hardware in a consistent
254 * state before rebooting the computer.
256 * To include this method in a device driver, use a line like this
257 * in the driver's method list:
260 * KOBJMETHOD(device_shutdown, foo_shutdown)
263 METHOD int shutdown {
265 } DEFAULT null_shutdown;
268 * @brief This is called by the power-management subsystem when a
269 * suspend has been requested by the user or by some automatic
272 * This gives drivers a chance to veto the suspend or save their
273 * configuration before power is removed.
275 * To include this method in a device driver, use a line like this in
276 * the driver's method list:
279 * KOBJMETHOD(device_suspend, foo_suspend)
282 * @param dev the device being suspended
285 * @retval non-zero an error occurred while attempting to prepare the
286 * device for suspension
288 * @see DEVICE_RESUME()
292 } DEFAULT null_suspend;
295 * @brief This is called when the system resumes after a suspend.
297 * To include this method in a device driver, use a line like this
298 * in the driver's method list:
301 * KOBJMETHOD(device_resume, foo_resume)
304 * @param dev the device being resumed
307 * @retval non-zero an error occurred while attempting to restore the
308 * device from suspension
310 * @see DEVICE_SUSPEND()
314 } DEFAULT null_resume;
317 * @brief This is called when the driver is asked to quiesce itself.
319 * The driver should arrange for the orderly shutdown of this device.
320 * All further access to the device should be curtailed. Soon there
321 * will be a request to detach, but there won't necessarily be one.
323 * To include this method in a device driver, use a line like this
324 * in the driver's method list:
327 * KOBJMETHOD(device_quiesce, foo_quiesce)
330 * @param dev the device being quiesced
333 * @retval non-zero an error occurred while attempting to quiesce the
336 * @see DEVICE_DETACH()
340 } DEFAULT null_quiesce;
343 * @brief This is called when the driver is asked to register handlers.
346 * To include this method in a device driver, use a line like this
347 * in the driver's method list:
350 * KOBJMETHOD(device_register, foo_register)
353 * @param dev the device for which handlers are being registered
355 * @retval NULL method not implemented
356 * @retval non-NULL a pointer to implementation specific static driver state
359 METHOD void * register {
361 } DEFAULT null_register;