|CONFIG_SEARCH(9)||Kernel Developer's Manual||CONFIG_SEARCH(9)|
func, struct device
struct device *
*parent, void *aux, cfprint_t
print, cfmatch_t submatch);
struct device *
device *parent, void
struct device *
The autoconfiguration framework supports direct configuration where the bus driver can determine the devices present.
The autoconfiguration framework also supports indirect configuration where the drivers must probe the bus looking for the presence of a device. Direct configuration is preferred since it can find hardware regardless of the presence of proper drivers.
The autoconfiguration process occurs at system bootstrap and is driven by a table generated from a “machine description” file by config(8). For a description of the config(8) “device definition” language, see files.conf(5).
Each device must have a name consisting of an alphanumeric string that ends with a unit number. The unit number identifies an instance of the driver. Device data structures are allocated dynamically during autoconfiguration, giving a unique address for each instance.
config_search() function performs indirect configuration of physical devices by iterating over all potential children, calling the given function func for each one.
config_rootsearch() function finds the
root device identified by the string rootname, in a
manner similar to
config_search(), except that there
is no parent device. If func is
applies each child's match function instead. The argument
parent is the pointer to the parent's device
structure. The given aux argument describes the device
that has been found and is simply passed on through
func to the child.
config_search() returns a pointer to the
best-matched child or
The role of func is to call the match
function for each device and call
for any positive matches.
typedef int (*cfmatch_t)(struct device *parent, void *child, void *aux);
If func is
then the parent should record the return value from
config_search() and call
Note that this function is designed so that it can be used to apply an arbitrary function to all potential children. In this case callers may choose to ignore the return value.
config_found_sm() function performs direct configuration on a physical device.
config_found_sm() is called by the parent and in turn calls the submatch function to call the match function as determined by the configuration table. If submatch is
NULL, the driver match functions are called directly. The argument parent is the pointer to the parent's device structure. The given aux argument describes the device that has been found. The softc structure for the matched device will be allocated, and the appropriate driver attach function will be called.
If the device is matched, the system prints the name of the child
and parent devices, and then calls the print function
to produce additional information if desired. If no driver takes a match,
the same print function is called to complain. The
print function is called with the aux argument and, if
the matches failed, the full name (including unit number) of the parent
typedef int (*cfprint_t)(void *aux, const char *parentname); #define QUIET 0 /* print nothing */ #define UNCONF 1 /* print " not configured" */ #define UNSUPP 2 /* print " not supported" */
Two special strings, “not configured” and
“unsupported” will be appended automatically to non-driver
reports if the return value is
UNSUPP respectively, otherwise the function should
return the value
config_found_sm() function returns a
pointer to the attached device's softc structure if the
device is attached,
NULL otherwise. Most callers can
ignore this value, since the system will already have printed a
config_found() macro expands to
submatch) with submatch set to
NULL and is provided for compatibility with older
config_rootfound() function performs
the same operation on the root device identified by the
|April 18, 2018||OpenBSD-current|