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-rw-r--r--hw/timer/sse-timer.c470
1 files changed, 470 insertions, 0 deletions
diff --git a/hw/timer/sse-timer.c b/hw/timer/sse-timer.c
new file mode 100644
index 0000000000..8dbe6ac651
--- /dev/null
+++ b/hw/timer/sse-timer.c
@@ -0,0 +1,470 @@
+/*
+ * Arm SSE Subsystem System Timer
+ *
+ * Copyright (c) 2020 Linaro Limited
+ * Written by Peter Maydell
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 or
+ * (at your option) any later version.
+ */
+
+/*
+ * This is a model of the "System timer" which is documented in
+ * the Arm SSE-123 Example Subsystem Technical Reference Manual:
+ * https://developer.arm.com/documentation/101370/latest/
+ *
+ * The timer is based around a simple 64-bit incrementing counter
+ * (readable from CNTPCT_HI/LO). The timer fires when
+ * Counter - CompareValue >= 0.
+ * The CompareValue is guest-writable, via CNTP_CVAL_HI/LO.
+ * CNTP_TVAL is an alternative view of the CompareValue defined by
+ * TimerValue = CompareValue[31:0] - Counter[31:0]
+ * which can be both read and written.
+ * This part is similar to the generic timer in an Arm A-class CPU.
+ *
+ * The timer also has a separate auto-increment timer. When this
+ * timer is enabled, then the AutoIncrValue is set to:
+ * AutoIncrValue = Reload + Counter
+ * and this timer fires when
+ * Counter - AutoIncrValue >= 0
+ * at which point, an interrupt is generated and the new AutoIncrValue
+ * is calculated.
+ * When the auto-increment timer is enabled, interrupt generation
+ * via the compare/timervalue registers is disabled.
+ */
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/timer.h"
+#include "qapi/error.h"
+#include "trace.h"
+#include "hw/timer/sse-timer.h"
+#include "hw/timer/sse-counter.h"
+#include "hw/sysbus.h"
+#include "hw/irq.h"
+#include "hw/registerfields.h"
+#include "hw/clock.h"
+#include "hw/qdev-clock.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+
+REG32(CNTPCT_LO, 0x0)
+REG32(CNTPCT_HI, 0x4)
+REG32(CNTFRQ, 0x10)
+REG32(CNTP_CVAL_LO, 0x20)
+REG32(CNTP_CVAL_HI, 0x24)
+REG32(CNTP_TVAL, 0x28)
+REG32(CNTP_CTL, 0x2c)
+ FIELD(CNTP_CTL, ENABLE, 0, 1)
+ FIELD(CNTP_CTL, IMASK, 1, 1)
+ FIELD(CNTP_CTL, ISTATUS, 2, 1)
+REG32(CNTP_AIVAL_LO, 0x40)
+REG32(CNTP_AIVAL_HI, 0x44)
+REG32(CNTP_AIVAL_RELOAD, 0x48)
+REG32(CNTP_AIVAL_CTL, 0x4c)
+ FIELD(CNTP_AIVAL_CTL, EN, 0, 1)
+ FIELD(CNTP_AIVAL_CTL, CLR, 1, 1)
+REG32(CNTP_CFG, 0x50)
+ FIELD(CNTP_CFG, AIVAL, 0, 4)
+#define R_CNTP_CFG_AIVAL_IMPLEMENTED 1
+REG32(PID4, 0xFD0)
+REG32(PID5, 0xFD4)
+REG32(PID6, 0xFD8)
+REG32(PID7, 0xFDC)
+REG32(PID0, 0xFE0)
+REG32(PID1, 0xFE4)
+REG32(PID2, 0xFE8)
+REG32(PID3, 0xFEC)
+REG32(CID0, 0xFF0)
+REG32(CID1, 0xFF4)
+REG32(CID2, 0xFF8)
+REG32(CID3, 0xFFC)
+
+/* PID/CID values */
+static const int timer_id[] = {
+ 0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */
+ 0xb7, 0xb0, 0x0b, 0x00, /* PID0..PID3 */
+ 0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
+};
+
+static bool sse_is_autoinc(SSETimer *s)
+{
+ return (s->cntp_aival_ctl & R_CNTP_AIVAL_CTL_EN_MASK) != 0;
+}
+
+static bool sse_enabled(SSETimer *s)
+{
+ return (s->cntp_ctl & R_CNTP_CTL_ENABLE_MASK) != 0;
+}
+
+static uint64_t sse_cntpct(SSETimer *s)
+{
+ /* Return the CNTPCT value for the current time */
+ return sse_counter_for_timestamp(s->counter,
+ qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL));
+}
+
+static bool sse_timer_status(SSETimer *s)
+{
+ /*
+ * Return true if timer condition is met. This is used for both
+ * the CNTP_CTL.ISTATUS bit and for whether (unless masked) we
+ * assert our IRQ.
+ * The documentation is unclear about the behaviour of ISTATUS when
+ * in autoincrement mode; we assume that it follows CNTP_AIVAL_CTL.CLR
+ * (ie whether the autoincrement timer is asserting the interrupt).
+ */
+ if (!sse_enabled(s)) {
+ return false;
+ }
+
+ if (sse_is_autoinc(s)) {
+ return s->cntp_aival_ctl & R_CNTP_AIVAL_CTL_CLR_MASK;
+ } else {
+ return sse_cntpct(s) >= s->cntp_cval;
+ }
+}
+
+static void sse_update_irq(SSETimer *s)
+{
+ bool irqstate = (!(s->cntp_ctl & R_CNTP_CTL_IMASK_MASK) &&
+ sse_timer_status(s));
+
+ qemu_set_irq(s->irq, irqstate);
+}
+
+static void sse_set_timer(SSETimer *s, uint64_t nexttick)
+{
+ /* Set the timer to expire at nexttick */
+ uint64_t expiry = sse_counter_tick_to_time(s->counter, nexttick);
+
+ if (expiry <= INT64_MAX) {
+ timer_mod_ns(&s->timer, expiry);
+ } else {
+ /*
+ * nexttick is so far in the future that it would overflow the
+ * signed 64-bit range of a QEMUTimer. Since timer_mod_ns()
+ * expiry times are absolute, not relative, we are never going
+ * to be able to set the timer to this value, so we must just
+ * assume that guest execution can never run so long that it
+ * reaches the theoretical point when the timer fires.
+ * This is also the code path for "counter is not running",
+ * which is signalled by expiry == UINT64_MAX.
+ */
+ timer_del(&s->timer);
+ }
+}
+
+static void sse_recalc_timer(SSETimer *s)
+{
+ /* Recalculate the normal timer */
+ uint64_t count, nexttick;
+
+ if (sse_is_autoinc(s)) {
+ return;
+ }
+
+ if (!sse_enabled(s)) {
+ timer_del(&s->timer);
+ return;
+ }
+
+ count = sse_cntpct(s);
+
+ if (count >= s->cntp_cval) {
+ /*
+ * Timer condition already met. In theory we have a transition when
+ * the count rolls back over to 0, but that is so far in the future
+ * that it is not representable as a timer_mod() expiry, so in
+ * fact sse_set_timer() will always just delete the timer.
+ */
+ nexttick = UINT64_MAX;
+ } else {
+ /* Next transition is when count hits cval */
+ nexttick = s->cntp_cval;
+ }
+ sse_set_timer(s, nexttick);
+ sse_update_irq(s);
+}
+
+static void sse_autoinc(SSETimer *s)
+{
+ /* Auto-increment the AIVAL, and set the timer accordingly */
+ s->cntp_aival = sse_cntpct(s) + s->cntp_aival_reload;
+ sse_set_timer(s, s->cntp_aival);
+}
+
+static void sse_timer_cb(void *opaque)
+{
+ SSETimer *s = SSE_TIMER(opaque);
+
+ if (sse_is_autoinc(s)) {
+ uint64_t count = sse_cntpct(s);
+
+ if (count >= s->cntp_aival) {
+ /* Timer condition met, set CLR and do another autoinc */
+ s->cntp_aival_ctl |= R_CNTP_AIVAL_CTL_CLR_MASK;
+ s->cntp_aival = count + s->cntp_aival_reload;
+ }
+ sse_set_timer(s, s->cntp_aival);
+ sse_update_irq(s);
+ } else {
+ sse_recalc_timer(s);
+ }
+}
+
+static uint64_t sse_timer_read(void *opaque, hwaddr offset, unsigned size)
+{
+ SSETimer *s = SSE_TIMER(opaque);
+ uint64_t r;
+
+ switch (offset) {
+ case A_CNTPCT_LO:
+ r = extract64(sse_cntpct(s), 0, 32);
+ break;
+ case A_CNTPCT_HI:
+ r = extract64(sse_cntpct(s), 32, 32);
+ break;
+ case A_CNTFRQ:
+ r = s->cntfrq;
+ break;
+ case A_CNTP_CVAL_LO:
+ r = extract64(s->cntp_cval, 0, 32);
+ break;
+ case A_CNTP_CVAL_HI:
+ r = extract64(s->cntp_cval, 32, 32);
+ break;
+ case A_CNTP_TVAL:
+ r = extract64(s->cntp_cval - sse_cntpct(s), 0, 32);
+ break;
+ case A_CNTP_CTL:
+ r = s->cntp_ctl;
+ if (sse_timer_status(s)) {
+ r |= R_CNTP_CTL_ISTATUS_MASK;
+ }
+ break;
+ case A_CNTP_AIVAL_LO:
+ r = extract64(s->cntp_aival, 0, 32);
+ break;
+ case A_CNTP_AIVAL_HI:
+ r = extract64(s->cntp_aival, 32, 32);
+ break;
+ case A_CNTP_AIVAL_RELOAD:
+ r = s->cntp_aival_reload;
+ break;
+ case A_CNTP_AIVAL_CTL:
+ /*
+ * All the bits of AIVAL_CTL are documented as WO, but this is probably
+ * a documentation error. We implement them as readable.
+ */
+ r = s->cntp_aival_ctl;
+ break;
+ case A_CNTP_CFG:
+ r = R_CNTP_CFG_AIVAL_IMPLEMENTED << R_CNTP_CFG_AIVAL_SHIFT;
+ break;
+ case A_PID4 ... A_CID3:
+ r = timer_id[(offset - A_PID4) / 4];
+ break;
+ default:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "SSE System Timer read: bad offset 0x%x",
+ (unsigned) offset);
+ r = 0;
+ break;
+ }
+
+ trace_sse_timer_read(offset, r, size);
+ return r;
+}
+
+static void sse_timer_write(void *opaque, hwaddr offset, uint64_t value,
+ unsigned size)
+{
+ SSETimer *s = SSE_TIMER(opaque);
+
+ trace_sse_timer_write(offset, value, size);
+
+ switch (offset) {
+ case A_CNTFRQ:
+ s->cntfrq = value;
+ break;
+ case A_CNTP_CVAL_LO:
+ s->cntp_cval = deposit64(s->cntp_cval, 0, 32, value);
+ sse_recalc_timer(s);
+ break;
+ case A_CNTP_CVAL_HI:
+ s->cntp_cval = deposit64(s->cntp_cval, 32, 32, value);
+ sse_recalc_timer(s);
+ break;
+ case A_CNTP_TVAL:
+ s->cntp_cval = sse_cntpct(s) + sextract64(value, 0, 32);
+ sse_recalc_timer(s);
+ break;
+ case A_CNTP_CTL:
+ {
+ uint32_t old_ctl = s->cntp_ctl;
+ value &= R_CNTP_CTL_ENABLE_MASK | R_CNTP_CTL_IMASK_MASK;
+ s->cntp_ctl = value;
+ if ((old_ctl ^ s->cntp_ctl) & R_CNTP_CTL_ENABLE_MASK) {
+ if (sse_enabled(s)) {
+ if (sse_is_autoinc(s)) {
+ sse_autoinc(s);
+ } else {
+ sse_recalc_timer(s);
+ }
+ }
+ }
+ sse_update_irq(s);
+ break;
+ }
+ case A_CNTP_AIVAL_RELOAD:
+ s->cntp_aival_reload = value;
+ break;
+ case A_CNTP_AIVAL_CTL:
+ {
+ uint32_t old_ctl = s->cntp_aival_ctl;
+
+ /* EN bit is writeable; CLR bit is write-0-to-clear, write-1-ignored */
+ s->cntp_aival_ctl &= ~R_CNTP_AIVAL_CTL_EN_MASK;
+ s->cntp_aival_ctl |= value & R_CNTP_AIVAL_CTL_EN_MASK;
+ if (!(value & R_CNTP_AIVAL_CTL_CLR_MASK)) {
+ s->cntp_aival_ctl &= ~R_CNTP_AIVAL_CTL_CLR_MASK;
+ }
+ if ((old_ctl ^ s->cntp_aival_ctl) & R_CNTP_AIVAL_CTL_EN_MASK) {
+ /* Auto-increment toggled on/off */
+ if (sse_enabled(s)) {
+ if (sse_is_autoinc(s)) {
+ sse_autoinc(s);
+ } else {
+ sse_recalc_timer(s);
+ }
+ }
+ }
+ sse_update_irq(s);
+ break;
+ }
+ case A_CNTPCT_LO:
+ case A_CNTPCT_HI:
+ case A_CNTP_CFG:
+ case A_CNTP_AIVAL_LO:
+ case A_CNTP_AIVAL_HI:
+ case A_PID4 ... A_CID3:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "SSE System Timer write: write to RO offset 0x%x\n",
+ (unsigned)offset);
+ break;
+ default:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "SSE System Timer write: bad offset 0x%x\n",
+ (unsigned)offset);
+ break;
+ }
+}
+
+static const MemoryRegionOps sse_timer_ops = {
+ .read = sse_timer_read,
+ .write = sse_timer_write,
+ .endianness = DEVICE_LITTLE_ENDIAN,
+ .valid.min_access_size = 4,
+ .valid.max_access_size = 4,
+};
+
+static void sse_timer_reset(DeviceState *dev)
+{
+ SSETimer *s = SSE_TIMER(dev);
+
+ trace_sse_timer_reset();
+
+ timer_del(&s->timer);
+ s->cntfrq = 0;
+ s->cntp_ctl = 0;
+ s->cntp_cval = 0;
+ s->cntp_aival = 0;
+ s->cntp_aival_ctl = 0;
+ s->cntp_aival_reload = 0;
+}
+
+static void sse_timer_counter_callback(Notifier *notifier, void *data)
+{
+ SSETimer *s = container_of(notifier, SSETimer, counter_notifier);
+
+ /* System counter told us we need to recalculate */
+ if (sse_enabled(s)) {
+ if (sse_is_autoinc(s)) {
+ sse_set_timer(s, s->cntp_aival);
+ } else {
+ sse_recalc_timer(s);
+ }
+ }
+}
+
+static void sse_timer_init(Object *obj)
+{
+ SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+ SSETimer *s = SSE_TIMER(obj);
+
+ memory_region_init_io(&s->iomem, obj, &sse_timer_ops,
+ s, "sse-timer", 0x1000);
+ sysbus_init_mmio(sbd, &s->iomem);
+ sysbus_init_irq(sbd, &s->irq);
+}
+
+static void sse_timer_realize(DeviceState *dev, Error **errp)
+{
+ SSETimer *s = SSE_TIMER(dev);
+
+ if (!s->counter) {
+ error_setg(errp, "counter property was not set");
+ }
+
+ s->counter_notifier.notify = sse_timer_counter_callback;
+ sse_counter_register_consumer(s->counter, &s->counter_notifier);
+
+ timer_init_ns(&s->timer, QEMU_CLOCK_VIRTUAL, sse_timer_cb, s);
+}
+
+static const VMStateDescription sse_timer_vmstate = {
+ .name = "sse-timer",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_TIMER(timer, SSETimer),
+ VMSTATE_UINT32(cntfrq, SSETimer),
+ VMSTATE_UINT32(cntp_ctl, SSETimer),
+ VMSTATE_UINT64(cntp_cval, SSETimer),
+ VMSTATE_UINT64(cntp_aival, SSETimer),
+ VMSTATE_UINT32(cntp_aival_ctl, SSETimer),
+ VMSTATE_UINT32(cntp_aival_reload, SSETimer),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static Property sse_timer_properties[] = {
+ DEFINE_PROP_LINK("counter", SSETimer, counter, TYPE_SSE_COUNTER, SSECounter *),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void sse_timer_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+
+ dc->realize = sse_timer_realize;
+ dc->vmsd = &sse_timer_vmstate;
+ dc->reset = sse_timer_reset;
+ device_class_set_props(dc, sse_timer_properties);
+}
+
+static const TypeInfo sse_timer_info = {
+ .name = TYPE_SSE_TIMER,
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(SSETimer),
+ .instance_init = sse_timer_init,
+ .class_init = sse_timer_class_init,
+};
+
+static void sse_timer_register_types(void)
+{
+ type_register_static(&sse_timer_info);
+}
+
+type_init(sse_timer_register_types);
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