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authorPeter Maydell <peter.maydell@linaro.org>2017-02-20 15:36:03 +0000
committerPeter Maydell <peter.maydell@linaro.org>2017-02-28 16:18:49 +0000
commitff68dacbc786d76a754b2c522cf70e22887bc8a6 (patch)
treea2cd081ec484499503bac1de17d034d50a08c37f /hw/intc/armv7m_nvic.c
parent743eb705608f21999356dd1bcefd4733f1c959e6 (diff)
armv7m: Split systick out from NVIC
The SysTick timer isn't really part of the NVIC proper; we just modelled it that way back when we couldn't easily have devices that only occupied a small chunk of a memory region. Split it out into its own device. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-id: 1487604965-23220-10-git-send-email-peter.maydell@linaro.org Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Diffstat (limited to 'hw/intc/armv7m_nvic.c')
-rw-r--r--hw/intc/armv7m_nvic.c160
1 files changed, 34 insertions, 126 deletions
diff --git a/hw/intc/armv7m_nvic.c b/hw/intc/armv7m_nvic.c
index c814e16e49..32ffa0bf35 100644
--- a/hw/intc/armv7m_nvic.c
+++ b/hw/intc/armv7m_nvic.c
@@ -58,65 +58,6 @@ static const uint8_t nvic_id[] = {
0x00, 0xb0, 0x1b, 0x00, 0x0d, 0xe0, 0x05, 0xb1
};
-/* qemu timers run at 1GHz. We want something closer to 1MHz. */
-#define SYSTICK_SCALE 1000ULL
-
-#define SYSTICK_ENABLE (1 << 0)
-#define SYSTICK_TICKINT (1 << 1)
-#define SYSTICK_CLKSOURCE (1 << 2)
-#define SYSTICK_COUNTFLAG (1 << 16)
-
-int system_clock_scale;
-
-/* Conversion factor from qemu timer to SysTick frequencies. */
-static inline int64_t systick_scale(NVICState *s)
-{
- if (s->systick.control & SYSTICK_CLKSOURCE)
- return system_clock_scale;
- else
- return 1000;
-}
-
-static void systick_reload(NVICState *s, int reset)
-{
- /* The Cortex-M3 Devices Generic User Guide says that "When the
- * ENABLE bit is set to 1, the counter loads the RELOAD value from the
- * SYST RVR register and then counts down". So, we need to check the
- * ENABLE bit before reloading the value.
- */
- if ((s->systick.control & SYSTICK_ENABLE) == 0) {
- return;
- }
-
- if (reset)
- s->systick.tick = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- s->systick.tick += (s->systick.reload + 1) * systick_scale(s);
- timer_mod(s->systick.timer, s->systick.tick);
-}
-
-static void systick_timer_tick(void * opaque)
-{
- NVICState *s = (NVICState *)opaque;
- s->systick.control |= SYSTICK_COUNTFLAG;
- if (s->systick.control & SYSTICK_TICKINT) {
- /* Trigger the interrupt. */
- armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK);
- }
- if (s->systick.reload == 0) {
- s->systick.control &= ~SYSTICK_ENABLE;
- } else {
- systick_reload(s, 0);
- }
-}
-
-static void systick_reset(NVICState *s)
-{
- s->systick.control = 0;
- s->systick.reload = 0;
- s->systick.tick = 0;
- timer_del(s->systick.timer);
-}
-
static int nvic_pending_prio(NVICState *s)
{
/* return the priority of the current pending interrupt,
@@ -462,30 +403,6 @@ static uint32_t nvic_readl(NVICState *s, uint32_t offset)
switch (offset) {
case 4: /* Interrupt Control Type. */
return ((s->num_irq - NVIC_FIRST_IRQ) / 32) - 1;
- case 0x10: /* SysTick Control and Status. */
- val = s->systick.control;
- s->systick.control &= ~SYSTICK_COUNTFLAG;
- return val;
- case 0x14: /* SysTick Reload Value. */
- return s->systick.reload;
- case 0x18: /* SysTick Current Value. */
- {
- int64_t t;
- if ((s->systick.control & SYSTICK_ENABLE) == 0)
- return 0;
- t = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- if (t >= s->systick.tick)
- return 0;
- val = ((s->systick.tick - (t + 1)) / systick_scale(s)) + 1;
- /* The interrupt in triggered when the timer reaches zero.
- However the counter is not reloaded until the next clock
- tick. This is a hack to return zero during the first tick. */
- if (val > s->systick.reload)
- val = 0;
- return val;
- }
- case 0x1c: /* SysTick Calibration Value. */
- return 10000;
case 0xd00: /* CPUID Base. */
return cpu->midr;
case 0xd04: /* Interrupt Control State. */
@@ -620,40 +537,8 @@ static uint32_t nvic_readl(NVICState *s, uint32_t offset)
static void nvic_writel(NVICState *s, uint32_t offset, uint32_t value)
{
ARMCPU *cpu = s->cpu;
- uint32_t oldval;
+
switch (offset) {
- case 0x10: /* SysTick Control and Status. */
- oldval = s->systick.control;
- s->systick.control &= 0xfffffff8;
- s->systick.control |= value & 7;
- if ((oldval ^ value) & SYSTICK_ENABLE) {
- int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
- if (value & SYSTICK_ENABLE) {
- if (s->systick.tick) {
- s->systick.tick += now;
- timer_mod(s->systick.timer, s->systick.tick);
- } else {
- systick_reload(s, 1);
- }
- } else {
- timer_del(s->systick.timer);
- s->systick.tick -= now;
- if (s->systick.tick < 0)
- s->systick.tick = 0;
- }
- } else if ((oldval ^ value) & SYSTICK_CLKSOURCE) {
- /* This is a hack. Force the timer to be reloaded
- when the reference clock is changed. */
- systick_reload(s, 1);
- }
- break;
- case 0x14: /* SysTick Reload Value. */
- s->systick.reload = value;
- break;
- case 0x18: /* SysTick Current Value. Writes reload the timer. */
- systick_reload(s, 1);
- s->systick.control &= ~SYSTICK_COUNTFLAG;
- break;
case 0xd04: /* Interrupt Control State. */
if (value & (1 << 31)) {
armv7m_nvic_set_pending(s, ARMV7M_EXCP_NMI);
@@ -952,16 +837,12 @@ static const VMStateDescription vmstate_VecInfo = {
static const VMStateDescription vmstate_nvic = {
.name = "armv7m_nvic",
- .version_id = 3,
- .minimum_version_id = 3,
+ .version_id = 4,
+ .minimum_version_id = 4,
.post_load = &nvic_post_load,
.fields = (VMStateField[]) {
VMSTATE_STRUCT_ARRAY(vectors, NVICState, NVIC_MAX_VECTORS, 1,
vmstate_VecInfo, VecInfo),
- VMSTATE_UINT32(systick.control, NVICState),
- VMSTATE_UINT32(systick.reload, NVICState),
- VMSTATE_INT64(systick.tick, NVICState),
- VMSTATE_TIMER_PTR(systick.timer, NVICState),
VMSTATE_UINT32(prigroup, NVICState),
VMSTATE_END_OF_LIST()
}
@@ -999,13 +880,26 @@ static void armv7m_nvic_reset(DeviceState *dev)
s->exception_prio = NVIC_NOEXC_PRIO;
s->vectpending = 0;
+}
- systick_reset(s);
+static void nvic_systick_trigger(void *opaque, int n, int level)
+{
+ NVICState *s = opaque;
+
+ if (level) {
+ /* SysTick just asked us to pend its exception.
+ * (This is different from an external interrupt line's
+ * behaviour.)
+ */
+ armv7m_nvic_set_pending(s, ARMV7M_EXCP_SYSTICK);
+ }
}
static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
{
NVICState *s = NVIC(dev);
+ SysBusDevice *systick_sbd;
+ Error *err = NULL;
s->cpu = ARM_CPU(qemu_get_cpu(0));
assert(s->cpu);
@@ -1020,10 +914,19 @@ static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
/* include space for internal exception vectors */
s->num_irq += NVIC_FIRST_IRQ;
+ object_property_set_bool(OBJECT(&s->systick), true, "realized", &err);
+ if (err != NULL) {
+ error_propagate(errp, err);
+ return;
+ }
+ systick_sbd = SYS_BUS_DEVICE(&s->systick);
+ sysbus_connect_irq(systick_sbd, 0,
+ qdev_get_gpio_in_named(dev, "systick-trigger", 0));
+
/* The NVIC and System Control Space (SCS) starts at 0xe000e000
* and looks like this:
* 0x004 - ICTR
- * 0x010 - 0x1c - systick
+ * 0x010 - 0xff - systick
* 0x100..0x7ec - NVIC
* 0x7f0..0xcff - Reserved
* 0xd00..0xd3c - SCS registers
@@ -1041,10 +944,11 @@ static void armv7m_nvic_realize(DeviceState *dev, Error **errp)
memory_region_init_io(&s->sysregmem, OBJECT(s), &nvic_sysreg_ops, s,
"nvic_sysregs", 0x1000);
memory_region_add_subregion(&s->container, 0, &s->sysregmem);
+ memory_region_add_subregion_overlap(&s->container, 0x10,
+ sysbus_mmio_get_region(systick_sbd, 0),
+ 1);
sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->container);
-
- s->systick.timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, systick_timer_tick, s);
}
static void armv7m_nvic_instance_init(Object *obj)
@@ -1059,8 +963,12 @@ static void armv7m_nvic_instance_init(Object *obj)
NVICState *nvic = NVIC(obj);
SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+ object_initialize(&nvic->systick, sizeof(nvic->systick), TYPE_SYSTICK);
+ qdev_set_parent_bus(DEVICE(&nvic->systick), sysbus_get_default());
+
sysbus_init_irq(sbd, &nvic->excpout);
qdev_init_gpio_out_named(dev, &nvic->sysresetreq, "SYSRESETREQ", 1);
+ qdev_init_gpio_in_named(dev, nvic_systick_trigger, "systick-trigger", 1);
}
static void armv7m_nvic_class_init(ObjectClass *klass, void *data)