Copyright (c) 2000 Sun Microsystems, Inc. All Rights Reserved
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#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);
Solaris DDI specific (Solaris DDI). This entry point is required, but it can be ddi_prop_op(9F).
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().
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.
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.
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));
}
Intro(9E), ddi_prop_op(9F), ddi_prop_update(9F)
Writing Device Drivers