SVR5

drvctl(D2)

drvctl -- handle custom I/O operations from another driver

Synopsis

   #include <sys/types.h>
   #include <sys/ddi.h>
   
   int prefixdrvctl(void *idata,
   	channel_t channel, int cmd,
   	void arg);

Description

The drvctl( ) entry point routine handles custom I/O operations from another driver.

Arguments

idata: For hardware drivers, a pointer to the device-specific instance data as output by the CFG_ADD subfunction of the config(D2) entry point routine. For software-only drivers, idata is undefined and should not be referenced. See ``Device instance'' in HDK Technical Reference.
channel: Channel number used to select subcomponents and/or operating modes of this device instance. See ``Channel number'' in HDK Technical Reference.
cmd: Command argument the driver drvctl( ) routine inteprets as the operation to be performed.
arg: Passes parameters between the calling driver and this driver. The interpretation of arg is dependent on the command and the driver. For example, the argument can be an integer or it can be the address of a structure that contains driver or hardware settings.

Return values

The drvctl( ) routine should return 0 for success, or the appropriate error number from those listed on the errnos(D5) manual page.

Usage

This entry point is optional.

The drvctl( ) entry point is similar to ioctl(D2), but is invoked from other kernel-level drivers rather than from user processes.

Context and synchronization

Blockable context. The driver can block but cannot do operations such as copyout(D3) that require access to the requesting process's address space.

Hardware applicability

All

Version applicability

ddi: 8, 8mp

References

do_drvctl(D3)