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If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner] .TH DDI_INTR_ADD_SOFTINT 9F "Oct 16, 2005" .SH NAME ddi_intr_add_softint, ddi_intr_remove_softint, ddi_intr_trigger_softint, ddi_intr_get_softint_pri, ddi_intr_set_softint_pri \- software interrupt handling routines .SH SYNOPSIS .nf #include #include #include #include \fBint\fR \fBddi_intr_add_softint\fR(\fBdev_info_t *\fR\fIdip\fR, \fBddi_softint_handle_t *\fR\fIh\fR, \fBint\fR \fIsoft_pri\fR, \fBddi_intr_handler_t\fR \fIhandler\fR, \fBvoid *\fR\fIarg1\fR); .fi .LP .nf \fBint\fR \fBddi_intr_trigger_softint\fR(\fBddi_softint_handle_t\fR \fIh\fR, \fBvoid *\fR\fIarg2\fR); .fi .LP .nf \fBint\fR \fBddi_intr_remove_softint\fR(\fBddi_softint_handle_t\fR \fIh\fR); .fi .LP .nf \fBint\fR \fBddi_intr_get_softint_pri\fR(\fBddi_softint_handle_t\fR \fIh\fR, \fBuint *\fR\fIsoft_prip\fR); .fi .LP .nf \fBint\fR \fBddi_intr_set_softint_pri\fR(\fBddi_softint_handle_t\fR \fIh\fR, \fBuint\fR \fIsoft_pri\fR); .fi .SH INTERFACE LEVEL illumos DDI specific (illumos DDI). .SH PARAMETERS \fBddi_intr_add_softint()\fR .sp .ne 2 .na \fB\fIdip\fR\fR .ad .RS 12n Pointer to a \fBdev_info\fR structure .RE .sp .ne 2 .na \fB\fIh\fR\fR .ad .RS 12n Pointer to the DDI soft interrupt handle .RE .sp .ne 2 .na \fB\fIsoft_pri\fR\fR .ad .RS 12n Priority to associate with a soft interrupt .RE .sp .ne 2 .na \fB\fIhandler\fR\fR .ad .RS 12n Pointer to soft interrupt handler .RE .sp .ne 2 .na \fB\fIarg1\fR\fR .ad .RS 12n Argument for the soft interrupt handler .RE .sp .LP \fBddi_intr_trigger_softint()\fR .sp .ne 2 .na \fB\fIh\fR\fR .ad .RS 8n DDI soft interrupt handle .RE .sp .ne 2 .na \fB\fIarg2\fR\fR .ad .RS 8n Additional argument for the soft interrupt handler .RE .sp .LP \fBddi_intr_remove_softint()\fR .sp .ne 2 .na \fB\fIh\fR\fR .ad .RS 5n DDI soft interrupt handle .RE .sp .LP \fBddi_intr_get_softint_pri()\fR .sp .ne 2 .na \fB\fIh\fR\fR .ad .RS 13n DDI soft interrupt handle .RE .sp .ne 2 .na \fB\fIsoft_prip\fR\fR .ad .RS 13n Soft interrupt priority of the handle .RE .sp .LP \fBddi_intr_set_softint_pri()\fR .sp .ne 2 .na \fB\fIh\fR\fR .ad .RS 13n DDI soft interrupt handle .RE .sp .ne 2 .na \fB\fIsoft_prip\fR\fR .ad .RS 13n Soft interrupt priority of the handle .RE .SH DESCRIPTION The \fBddi_intr_add_softint()\fR function adds the soft interrupt handler given by the \fIhandler\fR argument \fIarg1\fR. The \fIhandler\fR runs at the soft interrupt priority given by the \fIsoft_pri\fR argument. .sp .LP The value returned in the location pointed at by \fIh\fR is the soft interrupt handle. This value is used in later calls to \fBddi_intr_remove_softint()\fR, \fBddi_intr_trigger_softint()\fR and \fBddi_intr_set_softint_pri()\fR. .sp .LP The software priority argument \fIsoft_pri\fR is a relative priority value within the range of \fBDDI_INTR_SOFTPRI_MIN\fR and \fBDDI_INTR_SOFTPRI_MAX\fR. If the driver does not know what priority to use, the default \fIsoft_pri\fR value of \fBDDI_INTR_SOFTPRI_DEFAULT\fR could be specified. The default value is the lowest possible soft interrupt priority value. .sp .LP The \fIsoft_pri\fR argument contains the value needed to initialize the lock associated with a soft interrupt. See \fBmutex_init\fR(9F) and \fBrw_init\fR(9F). The handler cannot be triggered until the lock is initiatized. .sp .LP The \fBddi_intr_remove_softint()\fR function removes the handler for the soft interrupt identified by the interrupt handle \fIh\fR argument. Once removed, the soft interrupt can no longer be triggered, although any trigger calls in progress can still be delivered to the handler. .sp .LP Drivers must remove any soft interrupt handlers before allowing the system to unload the driver. Otherwise, kernel resource leaks might occur. .sp .LP The \fBddi_intr_trigger_softint()\fR function triggers the soft interrupt specified by the interrupt handler \fIh\fR argument. A driver may optionally specify an additional argument \fIarg2\fR that is passed to the soft interrupt handler. Subsequent \fBddi_intr_trigger_softint()\fR events, along with \fIarg2\fR, will be dropped until the one pending is serviced and returns the error code \fBDDI_EPENDING\fR. .sp .LP The routine \fIhandler\fR, with the \fIarg1\fR and \fIarg2\fR arguments, is called upon the receipt of a software interrupt. These were registered through a prior call to \fBddi_intr_add_softint()\fR. Software interrupt handlers must not assume that they have work to do when they run. Like hardware interrupt handlers, they may run because a soft interrupt has occurred for some other reason. For example, another driver may have triggered a soft interrupt at the same level. Before triggering the soft interrupt, the driver must indicate to the soft interrupt handler that it has work to do. This is usually done by setting a flag in the state structure. The routine \fIhandler\fR checks this flag, reached through \fIarg1\fR and \fIarg2\fR, to determine if it should claim the interrupt and do its work. .sp .LP The interrupt handler must return \fBDDI_INTR_CLAIMED\fR if the interrupt was claimed and \fBDDI_INTR_UNCLAIMED\fR otherwise. .sp .LP The \fBddi_intr_get_softint_pri()\fR function retrieves the soft interrupt priority, a small integer value, associated with the soft interrupt handle. The handle is defined by the \fIh\fR argument, and the priority returned is in the value of the integer pointed to by the \fIsoft_prip\fR argument. .SH RETURN VALUES The \fBddi_intr_add_softint()\fR, \fBddi_intr_remove_softint()\fR, \fBddi_intr_trigger_softint()\fR, \fBddi_intr_get_softint_pri()\fR, \fBddi_intr_set_softint_pri()\fR functions return: .sp .ne 2 .na \fB\fBDDI_SUCCESS\fR\fR .ad .RS 16n On success. .RE .sp .ne 2 .na \fB\fBDDI_EAGAIN\fR\fR .ad .RS 16n On encountering internal error regarding currently unavailable resources. .RE .sp .ne 2 .na \fB\fBDDI_EINVAL\fR\fR .ad .RS 16n On encountering invalid input parameters. .RE .sp .ne 2 .na \fB\fBDDI_FAILURE\fR\fR .ad .RS 16n On any implementation specific failure. .RE .sp .ne 2 .na \fB\fBDDI_EPENDING\fR\fR .ad .RS 16n On encountering a previously triggered softint event that is pending. .RE .SH CONTEXT The \fBddi_intr_add_softint()\fR, \fBddi_intr_remove_softint()\fR, \fBddi_intr_trigger_softint()\fR, \fBddi_intr_get_softint_pri()\fR, \fBddi_intr_set_softint_pri()\fR functions can be called from either user or kernel non-interrupt context. .SH EXAMPLES \fBExample 1 \fRDevice using high-level interrupts .sp .LP In the following example, the device uses high-level interrupts. High-level interrupts are those that interrupt at the level of the scheduler and above. High-level interrupts must be handled without using system services that manipulate thread or process states, because these interrupts are not blocked by the scheduler. In addition, high-level interrupt handlers must take care to do a minimum of work because they are not preemptable. See \fBddi_intr_get_hilevel_pri\fR(9F). .sp .LP In the example, the high-level interrupt routine minimally services the device, and enqueues the data for later processing by the soft interrupt handler. If the soft interrupt handler is not currently running, the high-level interrupt routine triggers a soft interrupt so the soft interrupt handler can process the data. Once running, the soft interrupt handler processes all the enqueued data before returning. .sp .LP The state structure contains two mutexes. The high-level mutex is used to protect data shared between the high-level interrupt handler and the soft interrupt handler. The low-level mutex is used to protect the rest of the driver from the soft interrupt handler. .sp .in +2 .nf struct xxstate { ... ddi_intr_handle_t int_hdl; int high_pri; kmutex_t high_mutex; ddi_softint_handle_t soft_hdl; int low_soft_pri; kmutex_t low_mutex; int softint_running; ... }; struct xxstate *xsp; static uint_t xxsoftint_handler(void *, void *); static uint_t xxhighintr(void *, void *); \&... .fi .in -2 .LP \fBExample 2 \fRSample \fBattach()\fR routine .sp .LP The following code fragment would usually appear in the driver's \fBattach\fR(9E) routine. \fBddi_intr_add_handler\fR(9F) is used to add the high-level interrupt handler and \fBddi_intr_add_softint()\fR is used to add the low-level interrupt routine. .sp .in +2 .nf static uint_t xxattach(dev_info_t *dip, ddi_attach_cmd_t cmd) { int types; int *actual; int nintrs; struct xxstate *xsp; ... (void) ddi_intr_get_supported_types(dip, &types); (void) ddi_intr_get_nintrs(dip< DDI_INTR_TYPE_FIXED, *nintrs); (void) ddi_intr_alloc(dip, &xsp->int_hdl, DDI_INTR_TYPE_FIXED, 1, nintrs, *actual, 0); /* initialize high-level mutex */ (void) ddi_intr_get_pri(xsp->int_hdl, &>high_pri); mutex_init(&xsp->high_mutex, NULL, MUTEX_DRIVER, DDI_INTR_PRI(xsp->high_pri)); /* Ensure that this is a hi-level interrupt */ if (ddi_intr_get_hilevel_pri(h) != DDI_SUCCESS) { /* cleanup */ return (DDI_FAILURE); /* fail attach */ } /* add high-level routine - xxhighintr() */ if (ddi_intr_add_handler(xsp->int_hdl, xxhighintr, arg1, NULL) != DDI_SUCCESS) { /* cleanup */ return (DDI_FAILURE); /* fail attach */ } /* Enable high-level routine - xxhighintr() */ if (ddi_intr_enable(xsp->int_hdl) != DDI_SUCCESS) { /* cleanup */ return (DDI_FAILURE); /* fail attach */ } /* Enable soft interrupts */ xsp->low_soft_pri = DDI_INTR_SOFTPRI_MIN; if (ddi_intr_add_softint(dip, &xsp>soft_hdl, xsp->low_soft_pri, xxsoftint_handler, arg1) != DDI_SUCCESS) { /* clean up */ return (DDI_FAILURE); /* fail attach */ } /* initialize low-level mutex */ mutex_init(&xsp->low_mutex, NULL, MUTEX_DRIVER, DDI_INTR_PRI(xsp->low_soft_pri)); ... } .fi .in -2 .LP \fBExample 3 \fRHigh-level interrupt routine .sp .LP The next code fragment represents the high-level interrupt routine. The high-level interrupt routine minimally services the device and enqueues the data for later processing by the soft interrupt routine. If the soft interrupt routine is not already running, \fBddi_intr_trigger_softint()\fR is called to start the routine. The soft interrupt routine will run until there is no more data on the queue. .sp .in +2 .nf static uint_t xxhighintr(void *arg1, void *arg2) { struct xxstate *xsp = (struct xxstate *)arg1; int need_softint; ... mutex_enter(&xsp->high_mutex); /* * Verify this device generated the interrupt * and disable the device interrupt. * Enqueue data for xxsoftint_handler() processing. */ /* is xxsoftint_handler() already running ? */ need_softint = (xsp->softint_running) ? 0 : 1; mutex_exit(&xsp->high_mutex); /* read-only access to xsp->id, no mutex needed */ if (xsp->soft_hdl && need_softint) ddi_intr_trigger_softint(xsp->soft_hdl, arg2); ... return (DDI_INTR_CLAIMED); } static uint_t xxsoftint_handler(void *arg1, void *arg2) { struct xxstate *xsp = (struct xxstate *)arg1; ... mutex_enter(&xsp->low_mutex); mutex_enter(&xsp->high_mutex); /* verify there is work to do */ if (work queue empty || xsp->softint_running ) { mutex_exit(&xsp->high_mutex); mutex_exit(&xsp->low_mutex); return (DDI_INTR_UNCLAIMED); } xsp->softint_running = 1; while ( data on queue ) { ASSERT(mutex_owned(&xsp->high_mutex)); /* de-queue data */ mutex_exit(&xsp->high_mutex); /* Process data on queue */ mutex_enter(&xsp->high_mutex); } xsp->softint_running = 0; mutex_exit(&xsp->high_mutex); mutex_exit(&xsp->low_mutex); return (DDI_INTR_CLAIMED); } .fi .in -2 .SH ATTRIBUTES See \fBattributes\fR(7) for descriptions of the following attributes: .sp .sp .TS box; c | c l | l . ATTRIBUTE TYPE ATTRIBUTE VALUE _ Interface Stability Evolving .TE .SH SEE ALSO .BR attributes (7), .BR attach (9E), .BR ddi_intr_alloc (9F), .BR ddi_intr_free (9F), .BR ddi_intr_get_hilevel_pri (9F), .BR mutex_init (9F), .BR rw_init (9F), .BR rwlock (9F) .sp .LP \fIWriting Device Drivers\fR .SH NOTES Consumers of these interfaces should verify that the return value is not equal to \fBDDI_SUCCESS\fR. Incomplete checking for failure codes could result in inconsistent behavior among platforms. .sp .LP The \fBddi_intr_add_softint()\fR may not be used to add the same software interrupt handler more than once. This is true even if a different value is used for \fIarg1\fR in each of the calls to \fBddi_intr_add_softint()\fR. Instead, the argument passed to the interrupt handler should indicate what service(s) the interrupt handler should perform. For example, the argument could be a pointer to the soft state structure of the device that could contain a \fBwhich_service\fR field that the handler examines. The driver must set this field to the appropriate value before calling \fBddi_intr_trigger_softint()\fR. .sp .LP Every time a modifiable valid second argument, \fIarg2\fR, is provided when \fBddi_intr_trigger_softint()\fR is invoked, the DDI framework saves \fIarg2\fR internally and passes it to the interrupt handler \fIhandler\fR. .sp .LP A call to \fBddi_intr_set_softint_pri()\fR could fail if a previously scheduled soft interrupt trigger is still pending.