Looking Up Properties

A driver can request a property from its parent, which in turn can ask its parent. The driver can control whether the request can go higher than its parent.

For example, the esp driver in the following example maintains an integer property called targetx-sync-speed for each target. The x in targetx-sync-speed represents the target number. The prtconf(1M) command displays driver properties in verbose mode. The following example shows a partial listing for the esp driver.

% prtconf -v
...
       esp, instance #0
            Driver software properties:
                name <target2-sync-speed> length <4>
                    value <0x00000fa0>.
...

The following table provides a summary of the property interfaces.

Table 4-1 Property Interface Uses

Family	Property Interfaces	Description
`ddi_prop_lookup`	`ddi_prop_exists`(9F)	Looks up a property and returns successfully if the property exists. Fails if the property does not exist
	`ddi_prop_get_int`(9F)	Looks up and returns an integer property
	`ddi_prop_get_int64`(9F)	Looks up and returns a 64-bit integer property
	`ddi_prop_lookup_int_array`(9F)	Looks up and returns an integer array property
	`ddi_prop_lookup_int64_array`(9F)	Looks up and returns a 64-bit integer array property
	`ddi_prop_lookup_string`(9F)	Looks up and returns a string property
	`ddi_prop_lookup_string_array`(9F)	Looks up and returns a string array property
	`ddi_prop_lookup_byte_array`(9F)	Looks up and returns a byte array property
`ddi_prop_update`	`ddi_prop_update_int`(9F)	Updates or creates an integer property
	`ddi_prop_update_int64`(9F)	Updates or creates a single 64-bit integer property
	`ddi_prop_update_int_array`(9F)	Updates or creates an integer array property
	`ddi_prop_update_string`(9F)	Updates or creates a string property
	`ddi_prop_update_string_array`(9F)	Updates or creates a string array property
	`ddi_prop_update_int64_array`(9F)	Updates or creates a 64-bit integer array property
	`ddi_prop_update_byte_array`(9F)	Updates or creates a byte array property
`ddi_prop_remove`	`ddi_prop_remove`(9F)	Removes a property
	`ddi_prop_remove_all`(9F)	Removes all properties that are associated with a device

Whenever possible, use 64-bit versions of int property interfaces such as ddi_prop_update_int64(9F) instead of 32-bit versions such as ddi_prop_update_int(9F)).