armv7m: Make NVIC expose a memory region rather than mapping itself

Make the NVIC device expose a memory region for its users
to map, rather than mapping itself into the system memory
space on realize, and get the one user (the ARMv7M object)
to do this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-id: 1487604965-23220-7-git-send-email-peter.maydell@linaro.org

hw/arm/armv7m.c

@@ -171,6 +171,7 @@ static void armv7m_instance_init(Object *obj)
 static void armv7m_realize(DeviceState *dev, Error **errp)
 {
     ARMv7MState *s = ARMV7M(dev);
+    SysBusDevice *sbd;
     Error *err = NULL;
     int i;
     char **cpustr;
@@ -232,10 +233,14 @@ static void armv7m_realize(DeviceState *dev, Error **errp)
     qdev_pass_gpios(DEVICE(&s->nvic), dev, "SYSRESETREQ");
 
     /* Wire the NVIC up to the CPU */
-    sysbus_connect_irq(SYS_BUS_DEVICE(&s->nvic), 0,
+    sbd = SYS_BUS_DEVICE(&s->nvic);
+    sysbus_connect_irq(sbd, 0,
                        qdev_get_gpio_in(DEVICE(s->cpu), ARM_CPU_IRQ));
     s->cpu->env.nvic = &s->nvic;
 
+    memory_region_add_subregion(&s->container, 0xe000e000,
+                                sysbus_mmio_get_region(sbd, 0));
+
     for (i = 0; i < ARRAY_SIZE(s->bitband); i++) {
         Object *obj = OBJECT(&s->bitband[i]);
         SysBusDevice *sbd = SYS_BUS_DEVICE(&s->bitband[i]);

hw/intc/armv7m_nvic.c

@@ -19,7 +19,6 @@
 #include "hw/arm/arm.h"
 #include "hw/arm/armv7m_nvic.h"
 #include "target/arm/cpu.h"
-#include "exec/address-spaces.h"
 #include "qemu/log.h"
 #include "trace.h"
 
@@ -1043,10 +1042,8 @@ static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
                           "nvic_sysregs", 0x1000);
     memory_region_add_subregion(&s->container, 0, &s->sysregmem);
 
-    /* Map the whole thing into system memory at the location required
-     * by the v7M architecture.
-     */
-    memory_region_add_subregion(get_system_memory(), 0xe000e000, &s->container);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->container);
+
     s->systick.timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, systick_timer_tick, s);
 }