Displaying the Device Tree (Writing Device Drivers)

Writing Device Drivers

Displaying the Device Tree

The device tree can be displayed in three ways. The libdevinfo library provides interfaces to access the contents of the device tree programmatically. The prtconf(1M) command displays the complete contents of the device tree. And, the /devices hierarchy is a representation of the device tree; use ls(1) to view it.

Note -

/devices displays only devices that have drivers configured into the system. prtconf(1M) shows all device nodes regardless of whether a driver for the device exists on the system or not.

`libdevinfo(3DEVINFO)`

libdevinfo(3DEVINFO) provides interfaces for accessing all public device configuration data. See libdevinfo(3LIB) for a list of interfaces. See http://soldc.sun.com/developer/support/driver/docs/whitepapers.html for the libdevinfo whitepaper.

`prtconf(1M)`

The prtconf(1M) command (excerpted example follows) displays all the devices in the system:

System Configuration:  Sun Microsystems  sun4u
Memory size: 128 Megabytes
System Peripherals (Software Nodes):

SUNW,Ultra-5_10
    packages (driver not attached)
        terminal-emulator (driver not attached)
        deblocker (driver not attached)
        obp-tftp (driver not attached)
        disk-label (driver not attached)
        SUNW,builtin-drivers (driver not attached)
        sun-keyboard (driver not attached)
        ufs-file-system (driver not attached)
    chosen (driver not attached)
    openprom (driver not attached)
        client-services (driver not attached)
    options, instance #0
    aliases (driver not attached)
    memory (driver not attached)
    virtual-memory (driver not attached)
    pci, instance #0
        pci, instance #0
            ebus, instance #0
                auxio (driver not attached)
                power, instance #0
                SUNW,pll (driver not attached)
                se, instance #0
                su, instance #0
                su, instance #1
                ecpp (driver not attached)
                fdthree, instance #0
                eeprom (driver not attached)
                flashprom (driver not attached)
                SUNW,CS4231 (driver not attached)
            network, instance #0
            SUNW,m64B (driver not attached)
            ide, instance #0
                disk (driver not attached)
                cdrom (driver not attached)
                dad, instance #0
                sd, instance #15
        pci, instance #1
            pci, instance #0
                pci108e,1000 (driver not attached)
                SUNW,hme, instance #1
                SUNW,isptwo, instance #0
                    sd (driver not attached)
                    st (driver not attached)
                    sd, instance #0 (driver not attached)
                    sd, instance #1 (driver not attached)
                    sd, instance #2 (driver not attached)
                    ....
    SUNW,UltraSPARC-IIi (driver not attached)
    SUNW,ffb, instance #0
    pseudo, instance #0

`/devices`

The /devices hierarchy provides a name space representing the device tree. Following is an abbreviated listing of the /devices name space. The sample output corresponds to the example device tree and prtconf(1M) output shown previously.

/devices
/devices/pseudo
/devices/pci@1f,0:devctl
/devices/SUNW,ffb@1e,0:ffb0
/devices/pci@1f,0
/devices/pci@1f,0/pci@1,1
/devices/pci@1f,0/pci@1,1/SUNW,m64B@2:m640
/devices/pci@1f,0/pci@1,1/ide@3:devctl
/devices/pci@1f,0/pci@1,1/ide@3:scsi
/devices/pci@1f,0/pci@1,1/ebus@1
/devices/pci@1f,0/pci@1,1/ebus@1/power@14,724000:power_button
/devices/pci@1f,0/pci@1,1/ebus@1/se@14,400000:a
/devices/pci@1f,0/pci@1,1/ebus@1/se@14,400000:b
/devices/pci@1f,0/pci@1,1/ebus@1/se@14,400000:0,hdlc
/devices/pci@1f,0/pci@1,1/ebus@1/se@14,400000:1,hdlc
/devices/pci@1f,0/pci@1,1/ebus@1/se@14,400000:a,cu
/devices/pci@1f,0/pci@1,1/ebus@1/se@14,400000:b,cu
/devices/pci@1f,0/pci@1,1/ebus@1/ecpp@14,3043bc:ecpp0
/devices/pci@1f,0/pci@1,1/ebus@1/fdthree@14,3023f0:a
/devices/pci@1f,0/pci@1,1/ebus@1/fdthree@14,3023f0:a,raw
/devices/pci@1f,0/pci@1,1/ebus@1/SUNW,CS4231@14,200000:sound,audio
/devices/pci@1f,0/pci@1,1/ebus@1/SUNW,CS4231@14,200000:sound,audioctl
/devices/pci@1f,0/pci@1,1/ide@3
/devices/pci@1f,0/pci@1,1/ide@3/sd@2,0:a
/devices/pci@1f,0/pci@1,1/ide@3/sd@2,0:a,raw
/devices/pci@1f,0/pci@1,1/ide@3/dad@0,0:a
/devices/pci@1f,0/pci@1,1/ide@3/dad@0,0:a,raw
/devices/pci@1f,0/pci@1
/devices/pci@1f,0/pci@1/pci@2
/devices/pci@1f,0/pci@1/pci@2/SUNW,isptwo@4:devctl
/devices/pci@1f,0/pci@1/pci@2/SUNW,isptwo@4:scsi