gld(9F) Kernel Functions for Drivers gld(9F)NAME
gld, gld_mac_alloc, gld_mac_free, gld_register, gld_unregister,
gld_recv, gld_sched, gld_intr - Generic LAN Driver service routines
SYNOPSIS
#include <sys/gld.h>
gld_mac_info_t *gld_mac_alloc(dev_info_t *dip);
void gld_mac_free(gld_mac_info_t *macinfo);
int gld_register(dev_info_t *dip, char *name, gld_mac_info_t *macinfo);
int gld_unregister(gld_mac_info_t *macinfo);
void gld_recv(gld_mac_info_t *macinfo, mblk_t *mp);
void gld_sched(gld_mac_info_t *macinfo);
uint_t gld_intr(caddr_t);
void gld_linkstate(gld_mac_info_t *macinfo, int32_t newstate);
INTERFACE LEVEL
Solaris architecture specific (Solaris DDI).
PARAMETERS
macinfo Pointer to a gld_mac_info(9S) structure.
dip Pointer to dev_info structure.
name Device interface name.
mp Pointer to a message block containing a received packet.
newstate Media link state.
DESCRIPTIONgld_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 may
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().
gld_mac_free() frees a gld_mac_info(9S) structure previously allocated
by gld_mac_alloc().
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) struc‐
ture, and initialize several of its structure elements. See
gld_mac_info(9S) for more information. A successful call to gld_regis‐
ter() performs the following actions:
o links the device-specific driver with the GLD system;
o sets the device-specific driver's private data pointer
(using ddi_set_driver_private(9F)) to point to the macinfo
structure;
o creates the minor device node.
The device interface name passed to gld_register() must exactly match
the name of the driver module as it exists in the filesystem.
The driver's attach(9E) routine should return DDI_SUCCESS if gld_regis‐
ter() succeeds. If gld_register() returns DDI_FAILURE, the attach(9E)
routine should deallocate any resources it allocated before calling
gld_register() and then also return DDI_FAILURE.
gld_unregister() is called by the device driver's detach(9E) function,
and if successful, performs the following tasks:
o ensures the device's interrupts are stopped, calling the
driver's gldm_stop() routine if necessary;
o removes the minor device node;
o unlinks the device-specific driver from the GLD system.
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() returns DDI_FAILURE, the driver's
detach(9E) routine must leave the device operational and return
DDI_FAILURE.
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, duplicat‐
ing 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 may not be held during a call to gld_recv(): the interrupt
thread that calls gld_recv() may 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 could result in a panic due to recursive mutex
entry.
gld_sched() is called by the device driver to reschedule stalled out‐
bound 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 out‐
bound 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.)
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 inter‐
rupt from within that. In this case, gld_intr() may be specified as the
soft interrupt handler in the call to ddi_add_softintr().
gld_linkstate() is called by the device driver to notify GLD of changes
in the media link state. The newstate argument should be set to one of
the following:
GLD_LINKSTATE_DOWN The media link is unavailable.
GLD_LINKSTATE_UP The media link is unavailable.
GLD_LINKSTATE_UNKNOWN The status of the media link is unknown.
If a driver calls gld_linkstate(), it must also set the
GLD_CAP_LINKSTATE bit in the gldm_capabilties field of the
gld_mac_info(9S) structure.
RETURN VALUESgld_mac_alloc() returns a pointer to a new gld_mac_info(9S) structure.
gld_register() and gld_unregister() return:
DDI_SUCCESS on success.
DDI_FAILURE on failure.
gld_intr() returns a value appropriate for an interrupt handler.
SEE ALSOgld(7D), gld(9E), gld_mac_info(9S), gld_stats(9S), dlpi(7P),
attach(9E), ddi_add_intr(9F).
Writing Device Drivers
SunOS 5.11 28 Aug 2003 gld(9F)
