Tribblix: manual page: ddi_devid

DDI_DEVID_COMPARE(9F) Kernel Functions for Drivers DDI_DEVID_COMPARE(9F)

NAME

ddi_devid_compare, ddi_devid_free, ddi_devid_init,
ddi_devid_register, ddi_devid_sizeof, ddi_devid_str_decode,
ddi_devid_str_encode, ddi_devid_str_free, ddi_devid_get,
ddi_devid_unregister, ddi_devid_valid - kernel interfaces for device
ids

SYNOPSIS

int ddi_devid_compare(ddi_devid_t devid1, ddi_devid_t devid2);

size_t ddi_devid_sizeof(ddi_devid_t devid);

int ddi_devid_init(dev_info_t *dip, ushort_t devid_type,
ushort_t nbytes, void *id, ddi_devid_t *retdevid);

void ddi_devid_free(ddi_devid_t devid);

int ddi_devid_register(dev_info_t *dip, ddi_devid_t devid);

int ddi_devid_str_decode(char *devidstr, ddi_devid_t *retdevid,
char **retminor_name);

int ddi_devid_str_encode(ddi_devid_t devid, char *minor_name);

int ddi_devid_str_free(char *devidstr);

int ddi_devid_get(dev_info_t *dip, ddi_devid_t *retdevid);

void ddi_devid_unregister(dev_info_t *dip);

int ddi_devid_valid(ddi_devid_t devid);

PARAMETERS

devid
The device id address.

devidstr
The devid and minor_name represented as a string.

devid1
The first of two device id addresses to be compared
calling ddi_devid_compare().

devid2
The second of two device id addresses to be compared
calling ddi_devid_compare().

dip
A dev_info pointer, which identifies the device.

devid_type
The following device id types may be accepted by the
ddi_devid_init() function:

DEVID_SCSI3_WWN
World Wide Name associated with
SCSI-3 devices.

DEVID_SCSI_SERIAL
Vendor ID and serial number
associated with a SCSI device.
Note: This may only be used if
known to be unique; otherwise a
fabricated device id must be used.

DEVID_ENCAP
Device ID of another device. This
is for layered device driver
usage.

DEVID_FAB
Fabricated device ID.

minor_name
The minor name to be encoded.

nbytes
The length in bytes of device ID.

retdevid
The return address of the device ID.

retminor_name
The return address of a minor name. Free string with
ddi_devid_str_free().

INTERFACE LEVEL

illumos DDI specific (illumos DDI).

DESCRIPTION

The following routines are used to provide unique identifiers, device
IDs, for devices. Specifically, kernel modules use these interfaces
to identify and locate devices, independent of the device's physical
connection or its logical device name or number.

ddi_devid_compare() compares two device IDs byte-by-byte and
determines both equality and sort order.

ddi_devid_sizeof() returns the number of bytes allocated for the
passed in device ID (devid).

ddi_devid_init() allocates memory and initializes the opaque device
ID structure. This function does not store the devid. If the device
id is not derived from the device's firmware, it is the driver's
responsibility to store the devid on some reliable store. When a
devid_type of either DEVID_SCSI3_WWN, DEVID_SCSI_SERIAL, or
DEVID_ENCAP is accepted, an array of bytes (id) must be passed in
(nbytes).

When the devid_type DEVID_FAB is used, the array of bytes (id) must
be NULL and the length (nbytes) must be zero. The fabricated device
ids, DEVID_FAB will be initialized with the machine's host id and a
timestamp.

Drivers must free the memory allocated by this function, using the
ddi_devid_free() function.

ddi_devid_free() frees the memory allocated for the returned devid by
the ddi_devid_init() and devid_str_decode() functions.

ddi_devid_register() registers the device ID address (devid) with the
DDI framework, associating it with the dev_info passed in (dip). The
drivers must register device IDs at attach time. See attach(9E).

ddi_devid_unregister() removes the device ID address from the
dev_info passed in (dip). Drivers must use this function to
unregister the device ID when devices are being detached. This
function does not free the space allocated for the device ID. The
driver must free the space allocated for the device ID, using the
ddi_devid_free() function. See detach(9E).

ddi_devid_valid() validates the device ID (devid) passed in. The
driver must use this function to validate any fabricated device ID
that has been stored on a device.

The ddi_devid_get() function returns a pointer to the device ID
structure through retdevid if there is already a registered device ID
associated with the dev_info node. A driver can use this interface to
check and get the device ID associated with the dev_info node. It
returns DDI_FAILURE if no device ID is registered for the node.

The ddi_devid_get() function allocates memory for the opaque device
ID structure and initializes it with the associated device ID and
returns the pointer to it. The driver must free the memory allocated
by this function using the ddi_devid_free() function.

The ddi_devid_str_encode() function encodes a devid and minor_name
into a null-terminated ASCII string, returning a pointer to that
string. If both a devid and a minor_name are non-null, then a slash
(/) is used to separate the devid from the minor_name in the encoded
string. If minor_name is null, then only the devid is encoded. If the
devid is null, then the special string id0 is returned. Note that you
cannot compare the returned string against another string with
strcmp() to determine devid equality. The returned string must be
freed by calling devid_str_free().

The ddi_devid_str_decode() function takes a string previously
produced by the devid_str_encode(3DEVID) or ddi_devid_str_encode()
function and decodes the contained device ID and minor name,
allocating and returning pointers to the extracted parts through the
retdevid and retminor_name arguments. If the special devidstr id0 was
specified then the returned device ID and minor name will both be
null. A non-null returned devid must be freed by the caller through
the ddi_devid_free() function. A non-null returned minor name must be
freed by calling ddi_devid_str_free().

The ddi_devid_str_free() function is used to free all strings
returned by the ddi_devid functions (the ddi_devid_str_encode()
function return value and the returned retminor_name argument).

RETURN VALUES

ddi_devid_init() returns the following values:

DDI_SUCCESS
Success.

DDI_FAILURE
Out of memory. An invalid devid_type was passed
in.

ddi_devid_valid() returns the following values:

DDI_SUCCESS
Valid device ID.

DDI_FAILURE
Invalid device ID.

ddi_devid_register() returns the following values:

DDI_SUCCESS
Success.

DDI_FAILURE
Failure. The device ID is already registered or
the device ID is invalid.

ddi_devid_valid() returns the following values:

DDI_SUCCESS
Valid device ID.

DDI_FAILURE
Invalid device ID.

ddi_devid_get() returns the following values:

DDI_SUCCESS
Device ID is present and a pointer to it is
returned in retdevid.

DDI_FAILURE
No device ID is defined for this dev_info node.

ddi_devid_compare() returns the following values:

-1
The first device ID is less than the second device ID.

0
The first device ID is equal to the second device ID.

1
The first device ID is greater than the second device
ID.

ddi_devid_sizeof() returns the size of the devid in bytes. If called
with a null, then the number of bytes that must be allocated and
initialized to determine the size of a complete device ID is
returned.

ddi_devid_str_encode() returns a value of null to indicate failure.
Failure can be caused by attempting to encode an invalid devid. If
the return value is non-null then the caller must free the returned
string by using the devid_str_free() function.

ddi_devid_str_decode() returns the following values:

DDI_SUCCESS
Success.

DDI_FAILURE
Failure; the devidstr string was not valid.

CONTEXT

These functions can be called from a user or kernel context.