xref: /illumos-gate/usr/src/man/man9e/prop_op.9e (revision b210e77709da8e42dfe621e10ccf4be504206058)
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PROP_OP 9E "Jul 8, 1996"
NAME
prop_op - report driver property information
SYNOPSIS
#include <sys/types.h>
#include <sys/ddi.h>
#include <sys/sunddi.h>



int prefixprop_op(dev_t dev, dev_info_t *dip,
 ddi_prop_op_t prop_op, int flags, char *name, caddr_t valuep,
 int *lengthp);
INTERFACE LEVEL
illumos DDI specific (illumos DDI). This entry point is required, but it can be ddi_prop_op(9F).
ARGUMENTS
dev

Device number associated with this device.

dip

A pointer to the device information structure for this device.

prop_op

Property operator. Valid operators are: PROP_LEN

Get property length only. (valuep unaffected).

PROP_LEN_AND_VAL_BUF

Get length and value into caller's buffer. (valuep used as input).

PROP_LEN_AND_VAL_ALLOC

Get length and value into allocated buffer. (valuep returned as pointer to pointer to allocated buffer).

flags

The only possible flag value is: DDI_PROP_DONTPASS

Do not pass request to parent if property not found.

name

Pointer to name of property to be interrogated.

valuep

If prop_op is PROP_LEN_AND_VAL_BUF, this should be a pointer to the user's buffer. If prop_op is PROP_LEN_AND_VAL_ALLOC, this should be the address of a pointer.

lengthp

On exit, *lengthp will contain the property length. If prop_op is PROP_LEN_AND_VAL_BUF then lengthp should point to an int that contains the length of caller's buffer, before calling prop_op().

DESCRIPTION
prop_op() is an entry point which reports the values of certain properties of the driver or device to the system. Each driver must have a prefix prop_op entry point, but most drivers that do not need to create or manage their own properties can use ddi_prop_op() for this entry point. Then the driver can use ddi_prop_update(9F) to create properties for its device.
RETURN VALUES
prop_op() should return: DDI_PROP_SUCCESS

Property found and returned.

DDI_PROP_NOT_FOUND

Property not found.

DDI_PROP_UNDEFINED

Prop explicitly undefined.

DDI_PROP_NO_MEMORY

Property found, but unable to allocate memory. lengthp has the correct property length.

DDI_PROP_BUF_TOO_SMALL

Property found, but the supplied buffer is too small. lengthp has the correct property length.

EXAMPLES
Example 1 Using prop_op() to Report Property Information

In the following example, prop_op() intercepts requests for the temperature property. The driver tracks changes to temperature using a variable in the state structure in order to avoid frequent calls to ddi_prop_update(9F). The temperature property is only updated when a request is made for this property. It then uses the system routine ddi_prop_op(9F) to process the property request. If the property request is not specific to a device, the driver does not intercept the request. This is indicated when the value of the dev parameter is equal to DDI_DEV_T_ANY.

int temperature; /* current device temperature */
 .
 .
 .
static int
xxprop_op(dev_t dev, dev_info_t *dip, ddi_prop_op_t prop_op,
 int flags, char *name, caddr_t valuep, int *lengthp)
{
 int instance;
 struct xxstate *xsp;
 if (dev == DDI_DEV_T_ANY)
 goto skip;
 instance = getminor(dev);
 xsp = ddi_get_soft_state(statep, instance);
 if (xsp == NULL)
 return (DDI_PROP_NOT_FOUND);
 if (strcmp(name, "temperature") == 0) {
 ddi_prop_update_int(dev, dip,\e
 "temperature", temperature);
 }
 /* other cases... */
 skip:
 return (ddi_prop_op(dev, dip, prop_op, flags,\e
 name, valuep, lengthp));
}
SEE ALSO
Intro (9E), ddi_prop_op (9F), ddi_prop_update (9F)

Writing Device Drivers