DDI_CREATE_MINOR_NODE(9F) Kernel Functions for Drivers DDI_CREATE_MINOR_NODE(9F)

ddi_create_minor_node - Create a minor node for this device

#include <sys/stat.h>
#include <sys/sunddi.h>
int ddi_create_minor_node(dev_info_t *dip, const char *name,

int spec_type, minor_t minor_num, const char *node_type,
int flag);

illumos DDI specific (illumos DDI).

dip

A pointer to the device's dev_info structure.

name

The name of this particular minor device.

spec_type

S_IFCHR or S_IFBLK for character or block minor devices respectively.

minor_num

The minor number for this particular minor device.

node_type

Any string literal that uniquely identifies the type of node. The following predefined node types are provided with this release:

DDI_NT_SERIAL

For serial ports

DDI_NT_SERIAL_MB

For on board serial ports

DDI_NT_SERIAL_DO

For dial out ports

DDI_NT_SERIAL_MB_DO

For on board dial out ports

DDI_NT_BLOCK

For hard disks

DDI_NT_BLOCK_CHAN

For hard disks with channel or target numbers

DDI_NT_CD

For CDROM drives

DDI_NT_CD_CHAN

For CDROM drives with channel or target numbers

DDI_NT_FD

For floppy disks

DDI_NT_TAPE

For tape drives

DDI_NT_NET

For DLPI style 1 or style 2 network devices

DDI_NT_DISPLAY

For display devices

DDI_PSEUDO

For pseudo devices

flag

If the device is a clone device then this flag is set to CLONE_DEV else it is set to 0.

ddi_create_minor_node() provides the necessary information to enable the system to create the /dev and /devices hierarchies. The name is used to create the minor name of the block or character special file under the /devices hierarchy. At-sign (@), slash (/), and space are not allowed. The spec_type specifies whether this is a block or character device. The minor_num is the minor number for the device. The node_type is used to create the names in the /dev hierarchy that refers to the names in the /devices hierarchy. See disks(8), ports(8), tapes(8), devlinks(8). Finally flag determines if this is a clone device or not, and what device class the node belongs to.

ddi_create_minor_node() returns:

DDI_SUCCESS

Was able to allocate memory, create the minor data structure, and place it into the linked list of minor devices for this driver.

DDI_FAILURE

Minor node creation failed.

The ddi_create_minor_node() function can be called from user context. It is typically called from attach(9E) or ioctl(9E).

Example 1 Create Data Structure Describing Minor Device with Minor Number of 0

The following example creates a data structure describing a minor device called foo which has a minor number of 0. It is of type DDI_NT_BLOCK (a block device) and it is not a clone device.


ddi_create_minor_node(dip, "foo", S_IFBLK, 0, DDI_NT_BLOCK, 0);

add_drv(8), devlinks(8), disks(8), drvconfig(8), ports(8), tapes(8), attach(9E), ddi_remove_minor_node(9F)

Writing Device Drivers

If the driver is for a network device (node_type DDI_NT_NET), note that the driver name will undergo the driver name constraints identified in the NOTES section of dlpi(4P). Additionally, the minor name must match the driver name for a DLPI style 2 provider. If the driver is a DLPI style 1 provider, the minor name must also match the driver name with the exception that the ppa is appended to the minor name.

Non-gld(4D)-based DLPI network streams drivers are encouraged to switch to gld(4D). Failing this, a driver that creates DLPI style-2 minor nodes must specify CLONE_DEV for its style-2 ddi_create_minor_node() nodes and use qassociate(9F). A driver that supports both style-1 and style-2 minor nodes should return DDI_FAILURE for DDI_INFO_DEVT2INSTANCE and DDI_INFO_DEVT2DEVINFO getinfo(9E) calls to style-2 minor nodes. (The correct association is already established by qassociate(9F)). A driver that only supports style-2 minor nodes can use ddi_no_info(9F) for its getinfo(9E) implementation. For drivers that do not follow these rules, the results of a modunload(8) of the driver or a cfgadm(8) remove of hardware controlled by the driver are undefined.

Drivers must remove references to GLOBAL_DEV, NODEBOUND_DEV, NODESPECIFIC_DEV, and ENUMERATED_DEV to compile.

May 1, 2020 OmniOS