On 07/11/2020 14:52, Philippe Mathieu-Daudé wrote:
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]);
Good spot. I'm fairly confident the code has been like this for a long time, so I
don't see this is a being a critical fix for 5.2. I'll add it to my 6.0 TODO list.
ATB,
Mark.
