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$FreeBSD: releng/10.2/share/man/man9/DRIVER_MODULE.9 239510 2012-08-21 17:58:39Z jhb $
.Dd August 21, 2012 .Dt DRIVER_MODULE 9 .Os .Sh NAME .Nm DRIVER_MODULE , .Nm DRIVER_MODULE_ORDERED , .Nm EARLY_DRIVER_MODULE , .Nm EARLY_DRIVER_MODULE_ORDERED .Nd kernel driver declaration macro .Sh SYNOPSIS n sys/param.h n sys/kernel.h n sys/bus.h n sys/module.h .Fn DRIVER_MODULE name busname "driver_t driver" "devclass_t devclass" "modeventhand_t evh" "void *arg" .Fn DRIVER_MODULE_ORDERED name busname "driver_t driver" "devclass_t devclass" "modeventhand_t evh" "void *arg" "int order" .Fn EARLY_DRIVER_MODULE name busname "driver_t driver" "devclass_t devclass" "modeventhand_t evh" "void *arg" "enum sysinit_elem_order order" "int pass" .Fn EARLY_DRIVER_MODULE_ORDERED name busname "driver_t driver" "devclass_t devclass" "modeventhand_t evh" "void *arg" "enum sysinit_elem_order order" "int pass" .Sh DESCRIPTION The .Fn DRIVER_MODULE macro declares a kernel driver. .Fn DRIVER_MODULE expands to the real driver declaration, where the phrase .Fa name is used as the naming prefix for the driver and its functions. Note that it is supplied as plain text, and not a .Li char or .Li char * .
p .Fa busname is the parent bus of the driver (PCI, ISA, PPBUS and others), e.g.\& .Ql pci , .Ql isa , or .Ql ppbus .
p The identifier used in .Fn DRIVER_MODULE can be different from the driver name. Also, the same driver identifier can exist on different busses, which is a pretty clean way of making front ends for different cards using the same driver on the same or different busses. For example, the following is allowed:
p .Fn DRIVER_MODULE foo isa foo_driver foo_devclass NULL NULL ;
p .Fn DRIVER_MODULE foo pci foo_driver foo_devclass NULL NULL ;
p .Fa driver is the driver of type .Li driver_t , which contains the information about the driver and is therefore one of the two most important parts of the call to .Fn DRIVER_MODULE .
p The .Fa devclass argument contains the kernel-internal information about the device, which will be used within the kernel driver module.
p The .Fa evh argument is the event handler which is called when the driver (or module) is loaded or unloaded (see .Xr module 9 ) .
p The .Fa arg is unused at this time and should be a .Dv NULL pointer.
p The .Fn DRIVER_MODULE_ORDERED macro allows a driver to be registered in a specific order. This can be useful if a single kernel module contains multiple drivers that are inter-dependent. The .Fa order argument should be one of the .Xr SYSINIT 9 initialization ordering constants
q Dv SI_ORDER_* . The default order for a driver module is .Dv SI_ORDER_MIDDLE . Typically a module will specify an order of .Dv SI_ORDER_ANY for a single driver to ensure it is registered last.
p The .Fn EARLY_DRIVER_MODULE macro allows a driver to be registered for a specific pass level. The boot time probe and attach process makes multiple passes over the device tree. Certain critical drivers that provide basic services needed by other devices are attach during earlier passes. Most drivers are attached in a final general pass. A driver that attaches during an early pass must register for a specific pass level
q BUS_PASS_* via the .Fa pass argument. Once a driver is registered it is available to attach to devices for all subsequent passes.
p The .Fn EARLY_DRIVER_MODULE_ORDERED macro allows a driver to be registered both in a specific order and for a specific pass level. .Sh SEE ALSO .Xr device 9 , .Xr driver 9 , .Xr module 9 , .Xr SYSINIT 9 .Sh AUTHORS This manual page was written by .An Alexander Langer Aq alex@FreeBSD.org .