Solaris 8 Software Developer Supplement

Service Routines

gld_mac_info_t * gld_mac_alloc(dev_info_t * dip);

gld_mac_alloc() allocates a new gld_mac_info(9S) structure and returns a pointer to it. Some of the GLD-private elements of the structure might be initialized before gld_mac_alloc() returns; all other elements are initialized to zero. The device driver must initialize some structure members, as described in gld_mac_info(9S), before passing the mac_info pointer to gld_register().

void gld_mac_free(gld_mac_info_t * macinfo);

gld_mac_free() frees a gld_mac_info(9S) structure previously allocated by gld_mac_alloc().

int gld_register(dev_info_t * dip, char * name, gld_mac_info_t * macinfo);

gld_register() is called from the device driver's attach(9E) routine and is used to link the GLD-based device driver with the GLD framework. Before calling gld_register(), the device driver's attach(9E) routine must first use gld_mac_alloc() to allocate a gld_mac_info(9S) structure, and then initialize several of its structure elements. See lgld_mac_info(9S) for more information. A successful call to gld_register() performs the following actions:

The device interface name passed to gld_register() must exactly match the name of the driver module as it exists in the file system.

The driver's attach(9E) routine should return DDI_SUCCESS if gld_register() succeeds. If gld_register() does not return DDI_SUCCESS, the attach(9E) routine should deallocate any resources it allocated before calling gld_register(), and also return DDI_FAILURE.

int gld_unregister(gld_mac_info_t * macinfo);

gld_unregister() is called by the device driver's detach(9E) function, and if successful, performs the following tasks:

If gld_unregister() returns DDI_SUCCESS, the detach(9E) routine should deallocate any data structures allocated in the attach(9E) routine, using gld_mac_free() to deallocate the macinfo structure, and return DDI_SUCCESS. If gld_unregister() does not return DDI_SUCCESS, the driver's detach(9E) routine must leave the device operational and return DDI_FAILURE.

void gld_recv(gld_mac_info_t * macinfo, mblk_t * mp);

gld_recv() is called by the driver's interrupt handler to pass a received packet upstream. The driver must construct and pass a STREAMS M_DATA message containing the raw packet. gld_recv() determines which STREAMS queues, if any, should receive a copy of the packet, duplicating it if necessary. It then formats a DL_UNITDATA_IND message, if required, and passes the data up all appropriate STREAMS.

The driver should avoid holding mutex or other locks during the call to gld_recv(). In particular, locks that could be taken by a transmit thread cannot be held during a call to gld_recv(): the interrupt thread that calls gld_recv() will in some cases carry out processing that includes sending an outgoing packet, resulting in a call to the driver's gldm_send() routine. If the gldm_send() routine were to try to acquire a mutex being held by the gldm_intr() routine at the time it calls gld_recv(), this would result in a panic because of recursive mutex entry.

void gld_sched(gld_mac_info_t * macinfo);

gld_sched() is called by the device driver to reschedule stalled outbound packets. Whenever the driver's gldm_send() routine has returned GLD_NORESOURCES, the driver must later call gld_sched() to inform the GLD framework that it should retry the packets that previously could not be sent. gld_sched() should be called as soon as possible after resources are again available, to ensure that GLD resumes passing outbound packets to the driver's gldm_send() routine in a timely way. (If the driver's gldm_stop() routine is called, the driver is absolved from this obligation until it later again returns GLD_NORESOURCES from its gldm_send() routine; however, extra calls to gld_sched() will not cause incorrect operation.)

uint_t gld_intr(caddr_t);

gld_intr() is GLD's main interrupt handler. Normally, it is specified as the interrupt routine in the device driver's call to ddi_add_intr(9F). The argument to the interrupt handler (specified as int_handler_arg in the call to ddi_add_intr(9F)) must be a pointer to the gld_mac_info(9S) structure. gld_intr() will, when appropriate, call the device driver's gldm_intr() function, passing that pointer to the gld_mac_info(9S) structure. However, if the driver uses a high-level interrupt, it must provide its own high-level interrupt handler and trigger a soft interrupt from within that. In this case, gld_intr() can be specified as the soft interrupt handler in the call to ddi_add_softintr(). gld_intr() will return a value appropriate for an interrupt handler.