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

1 files changed, 16 insertions, 15 deletions

diff --git a/sys/x86/isa/atrtc.c b/sys/x86/isa/atrtc.c
index fe2a8768bb9a..dc0a89b3e341 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;