Cc'ing SPARC maintainers ... On 11/7/20 12:51 AM, Peter Maydell wrote: > The q800 board code connects both of the IRQ outputs of the ESCC > to the same pic[3] qemu_irq. Connecting two qemu_irqs outputs directly > to the same input is not valid as it produces subtly wrong behaviour > (for instance if both the IRQ lines are high, and then one goes > low, the PIC input will see this as a high-to-low transition > even though the second IRQ line should still be holding it high). > > This kind of wiring needs an explicitly created OR gate; add one. > > Signed-off-by: Peter Maydell <peter.mayd...@linaro.org> > --- > hw/m68k/q800.c | 12 ++++++++++-- > hw/m68k/Kconfig | 1 + > 2 files changed, 11 insertions(+), 2 deletions(-) > > diff --git a/hw/m68k/q800.c b/hw/m68k/q800.c > index ce4b47c3e34..dc13007aaf2 100644 > --- a/hw/m68k/q800.c > +++ b/hw/m68k/q800.c > @@ -28,6 +28,7 @@ > #include "hw/hw.h" > #include "hw/boards.h" > #include "hw/irq.h" > +#include "hw/or-irq.h" > #include "elf.h" > #include "hw/loader.h" > #include "ui/console.h" > @@ -171,6 +172,7 @@ static void q800_init(MachineState *machine) > CPUState *cs; > DeviceState *dev; > DeviceState *via_dev; > + DeviceState *escc_orgate; > SysBusESPState *sysbus_esp; > ESPState *esp; > SysBusDevice *sysbus; > @@ -283,8 +285,14 @@ static void q800_init(MachineState *machine) > qdev_prop_set_uint32(dev, "chnAtype", 0); > sysbus = SYS_BUS_DEVICE(dev); > sysbus_realize_and_unref(sysbus, &error_fatal); > - sysbus_connect_irq(sysbus, 0, pic[3]); > - sysbus_connect_irq(sysbus, 1, pic[3]);
... because sun4m_hw_init() has the same issue: 986 dev = qdev_new(TYPE_ESCC); ... 996 sysbus_connect_irq(s, 0, slavio_irq[14]); 997 sysbus_connect_irq(s, 1, slavio_irq[14]); ... 1011 sysbus_connect_irq(s, 0, slavio_irq[15]); 1012 sysbus_connect_irq(s, 1, slavio_irq[15]); > + > + /* Logically OR both its IRQs together */ > + escc_orgate = DEVICE(object_new(TYPE_OR_IRQ)); > + object_property_set_int(OBJECT(escc_orgate), "num-lines", 2, > &error_fatal); > + qdev_realize_and_unref(escc_orgate, NULL, &error_fatal); > + sysbus_connect_irq(sysbus, 0, qdev_get_gpio_in(escc_orgate, 0)); > + sysbus_connect_irq(sysbus, 1, qdev_get_gpio_in(escc_orgate, 1)); > + qdev_connect_gpio_out(DEVICE(escc_orgate), 0, pic[3]); > sysbus_mmio_map(sysbus, 0, SCC_BASE); > > /* SCSI */ > diff --git a/hw/m68k/Kconfig b/hw/m68k/Kconfig > index c757e7dfa48..60d7bcfb8f2 100644 > --- a/hw/m68k/Kconfig > +++ b/hw/m68k/Kconfig > @@ -22,3 +22,4 @@ config Q800 > select ESCC > select ESP > select DP8393X > + select OR_IRQ >
