Managing and Developing Dynamically Loadable Kernel Modules

Developing Dynamically Loadable Kernel Modules

Chapter 12 555

Also, set the following bit values in the flags ﬁeld in the drv_info_t

structure: if you have a block driver, set the DRV_BLOCK value; if you

have a character driver set the DRV_CHAR value; if your driver is both

a block and a character driver, set both values.

Note that this step applies only to statically conﬁgured modules. The

drv_info_t structure in driver source is ignored for dynamic

conﬁguration.

To create device special ﬁles for your driver, follow these steps:

1. Use the lsdev (1M) command to identify the major number assigned

to the device driver. lsdev lists all device drivers conﬁgured into the

kernel and their block and character major numbers.

To extract the block major number from the display for a driver

named mydriver, execute the following command:

/usr/sbin/lsdev -h -d mydriver | awk ’{print $2}’

To extract the character major number from the display for a driver

named mydriver, execute the following command:

/usr/sbin/lsdev -h -d mydriver | awk ’{print $1}’

As an alternative and assuming a dynamically loadable driver, you

can execute the following two commands to identify the major

number assigned to a driver named mydriver:

/usr/sbin/kmadmin -L mydriver

/usr/sbin/kmadmin -Q mydriver

2. Construct a minor number for each device special ﬁle that you create

for the driver. See Appendix C, “Major and Minor Numbers,” in the

Conﬁguring HP-UX For Peripherals document for more information

about bit assignments and dev_t.

3. Use the mknod command to create the device special ﬁles for the

driver.

In the example below, mydriver was dynamically assigned the block

and character major numbers 65 and 234, respectively. Its minor

number, 0x026000, is constructed like that of instr0 (bits 8 through

15 encode 2 as the instance of the interface card, and bits 16 through

19 encode 6 of the device’s address).

/usr/sbin/mknod /dev/mydriver b 65 0x026000

/usr/sbin/mknod /dev/mydriver c 234 0x026000