Add "legacy route" support to HPET driver. When enabled, this mode makes

HPET to steal IRQ0 from i8254 and IRQ8 from RTC timers. It can be suitable
for HPETs without FSB interrupts support, as it gives them two unshared
IRQs. It allows them to provide one per-CPU event timer on dual-CPU system,
that should be suitable for further tickless kernels.

To enable it, such lines may be added to /boot/loader.conf:
hint.atrtc.0.clock=0
hint.attimer.0.clock=0
hint.hpet.0.legacy_route=1

2 files changed, 32 insertions, 28 deletions

diff --git a/sys/x86/isa/atrtc.c b/sys/x86/isa/atrtc.c
index fe2a876..dc0a89b 100644
--- a/sys/x86/isa/atrtc.c
+++ b/sys/x86/isa/atrtc.c
@@ -244,34 +244,35 @@ static int
 atrtc_attach(device_t dev)
 {
 	struct atrtc_softc *sc;
-	int i, diag, haveirq = 0;
+	int i, diag;
 
 	sc = device_get_softc(dev);
 	if (!(sc->port_res = bus_alloc_resource(dev, SYS_RES_IOPORT,
 	    &sc->port_rid, IO_RTC, IO_RTC + 1, 2, RF_ACTIVE)))
 		device_printf(dev,"Warning: Couldn't map I/O.\n");
-	if (!(sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
-	    &sc->intr_rid, 8, 8, 1, RF_ACTIVE)))
-		device_printf(dev,"Couldn't map Interrupt.\n");
-	else if ((bus_setup_intr(dev, sc->intr_res,
-	    INTR_MPSAFE | INTR_TYPE_CLK, (driver_filter_t *)rtc_intr, NULL,
-	    sc, &sc->intr_handler))) {
-		device_printf(dev, "Can't setup interrupt.\n");
-	} else { 
-		haveirq = 1;
-		/* Bind IRQ to BSP to avoid live migration. */
-		bus_bind_intr(dev, sc->intr_res, 0);
-	}
 	diag = rtcin(RTC_DIAG);
 	if (diag != 0)
 		printf("RTC BIOS diagnostic error %b\n", diag, RTCDG_BITS);
 	atrtc_start();
 	clock_register(dev, 1000000);
 	bzero(&sc->et, sizeof(struct eventtimer));
-	if (haveirq &&
-	    !atrtcclock_disable &&
+	if (!atrtcclock_disable &&
 	    (resource_int_value(device_get_name(dev), device_get_unit(dev),
 	     "clock", &i) != 0 || i != 0)) {
+		if (!(sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
+		    &sc->intr_rid, 8, 8, 1, RF_ACTIVE))) {
+			device_printf(dev,"Can't map interrupt.\n");
+			return (0);
+		} else if ((bus_setup_intr(dev, sc->intr_res,
+		    INTR_MPSAFE | INTR_TYPE_CLK,
+		    (driver_filter_t *)rtc_intr, NULL,
+		    sc, &sc->intr_handler))) {
+			device_printf(dev, "Can't setup interrupt.\n");
+			return (0);
+		} else { 
+			/* Bind IRQ to BSP to avoid live migration. */
+			bus_bind_intr(dev, sc->intr_res, 0);
+		}
 		sc->et.et_name = "RTC";
 		sc->et.et_flags = ET_FLAGS_PERIODIC;
 		sc->et.et_quality = 0;
diff --git a/sys/x86/isa/clock.c b/sys/x86/isa/clock.c
index 5929f5b..69327d0 100644
--- a/sys/x86/isa/clock.c
+++ b/sys/x86/isa/clock.c
@@ -522,9 +522,6 @@ attimer_attach(device_t dev)
 
 	attimer_sc = sc = device_get_softc(dev);
 	bzero(sc, sizeof(struct attimer_softc));
-	if (!(sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
-	    &sc->intr_rid, 0, 0, 1, RF_ACTIVE)))
-		device_printf(dev,"Warning: Couldn't map Interrupt.\n");
 	i8254_intsrc = intr_lookup_source(0);
 	if (i8254_intsrc != NULL)
 		i8254_pending = i8254_intsrc->is_pic->pic_source_pending;
@@ -538,6 +535,11 @@ attimer_attach(device_t dev)
 	tc_init(&sc->tc);
 	if (resource_int_value(device_get_name(dev), device_get_unit(dev),
 	    "clock", &i) != 0 || i != 0) {
+		if (!(sc->intr_res = bus_alloc_resource(dev, SYS_RES_IRQ,
+		    &sc->intr_rid, 0, 0, 1, RF_ACTIVE))) {
+			device_printf(dev,"Can't map interrupt.\n");
+			return (0);
+		}
 		/* Dirty hack, to make bus_setup_intr to not enable source. */
 		i8254_intsrc->is_handlers++;
 		if ((bus_setup_intr(dev, sc->intr_res,
@@ -545,18 +547,19 @@ attimer_attach(device_t dev)
 		    (driver_filter_t *)clkintr, NULL,
 		    sc, &sc->intr_handler))) {
 			device_printf(dev, "Can't setup interrupt.\n");
-		} else {
-			i8254_intsrc->is_pic->pic_enable_intr(i8254_intsrc);
-			sc->et.et_name = "i8254";
-			sc->et.et_flags = ET_FLAGS_PERIODIC;
-			sc->et.et_quality = 100;
-			sc->et.et_frequency = i8254_freq;
-			sc->et.et_start = attimer_start;
-			sc->et.et_stop = attimer_stop;
-			sc->et.et_priv = dev;
-			et_register(&sc->et);
+			i8254_intsrc->is_handlers--;
+			return (0);
 		}
 		i8254_intsrc->is_handlers--;
+		i8254_intsrc->is_pic->pic_enable_intr(i8254_intsrc);
+		sc->et.et_name = "i8254";
+		sc->et.et_flags = ET_FLAGS_PERIODIC;
+		sc->et.et_quality = 100;
+		sc->et.et_frequency = i8254_freq;
+		sc->et.et_start = attimer_start;
+		sc->et.et_stop = attimer_stop;
+		sc->et.et_priv = dev;
+		et_register(&sc->et);
 	}
 	return(0);
 }