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| Driver Entry Points | prop_op(9E) |
| | prop_op - report driver property
information |
SYNOPSIS
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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); |
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Solaris DDI specific (Solaris DDI). This entry point is required,
but it can be ddi_prop_op(9F).
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dev
- Device number associated with this
device.
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dip
- A pointer to the device information structure for this device.
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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.
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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.
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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().
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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.
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prop_op() should return:
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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.
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| | Example 1. Using prop_op to Report
Property Information
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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.
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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, "temperature", temperature);
}
/* other cases... */
skip:
return (ddi_prop_op(dev, dip, prop_op, flags, name, valuep, lengthp));
}
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