hwgraph.dev(D3X)

NAME
     hwgraph.dev: hwgraph_block_device_add, hwgraph_char_device_add,
     hwgraph_chmod, device_info_set, device_info_get - create and use device
     vertex

SYNOPSIS
     #include <sys/types.h>
     #include <sys/hwgraph.h>
     #include <sys/ddi.h>

     graph_error_t
     hwgraph_block_device_add(vertex_hdl_t from_vhdl,
                         char *path,
                         char *driver_prefix,
                         vertex_hdl_t *vhdl_ptr);

     graph_error_t
     hwgraph_char_device_add(vertex_hdl_t from_vhdl,
                         char *path,
                         char *driver_prefix,
                         vertex_hdl_t *vhdl_ptr);

     void
     device_info_set(vertex_hdl_t device, void *info);

     void *
     device_info_get(vertex_hdl_t device);

     void
     hwgraph_chmod(vertex_hdl_t vhdl, mode_t mode);

   Arguments
     device      Vertex handle of a device vertex, typically one created by
                 hwgraph_block_device_add() or hwgraph_char_device_add().

     driver_prefix
                 The device driver character string prefix of the device
                 driver that is to manage the newly-created device.

     from_vhdl   Vertex handle that is the connection point of the device to
                 be described.  Typically the vertex handle passed to the
                 attach entry point of a device driver.

     mode        A standard file protection mode as declared in sys/stat.h.

     path        An edge name, or a sequence of edge names separated by
                 slashes (which looks exactly like a relative pathname in the
                 /hw filesystem).

     vhdl        A vertex handle of a device in the hwgraph.
     vhdl_ptr    A pointer to a field where a new vertex handle is returned.

DESCRIPTION
     The device_add functions operate on the hardware graph to add a new
     vertex that represents a block or a char device.  The new vertex is
     visible in /hw as a character or block device special file.  The device
     is controlled by the device driver that is identified by prefix, so that
     prefix_open() is called when the new vertex is opened.  When it is
     opened, the dev_t passed to the driver's open entry point matches the
     vertex_hdl_t returned in vhdl_ptr.

     The device_info_set() function associates a pointer-sized piece of
     information with a specified dev_t for later retrieval by
     device_info_get().  Typically, this information is a pointer to a per-
     device data structure allocated by the driver in its attach entry point.

     Caution:  A device driver should never change the device-info of any
     vertex that the device driver did not create.  In particular, the vertex
     that is passed to the attach() entry point of a PCI driver is owned by
     the PCI infrastructure.  If the driver sets the device-info of that
     connection-point vertex, the PCI infrastructure is likely to crash.  A
     driver is always free to change the device-info of a vertex that the
     driver itself creates using the device_add functions.

     hwgraph_chmod() sets the initial (default) access mode of the /hw
     representation of the specified vertex.

DIAGNOSTICS
     The *_device_add functions return GRAPH_SUCCESS when the operation
     completes successfully, or a failure code as listed in hwgraph(D3X) when
     the operation does not complete successfully.

     device_info_set() always succeeds and has no return value.  It is the
     caller's responsibility to pass a valid device; that is, a dev_t that
     represents a vertex in the hardware graph.

     device_info_get() returns the pointer-sized piece of information
     associated with the specified device.  This value is unpredictable until
     device_info_set() has been called.

SEE ALSO
     hwgraph.inv(D3X), hwgraph.intro(D4X).