Adding upstream version 1:7.2+dfsg.upstream/1%7.2+dfsgupstream

Signed-off-by: Daniel Baumann <mail@daniel-baumann.ch>

1 files changed, 485 insertions, 0 deletions

diff --git a/hw/core/ptimer.c b/hw/core/ptimer.c
new file mode 100644
index 00000000..eb5ba1af
--- /dev/null
+++ b/hw/core/ptimer.c
@@ -0,0 +1,485 @@
+/*
+ * General purpose implementation of a simple periodic countdown timer.
+ *
+ * Copyright (c) 2007 CodeSourcery.
+ *
+ * This code is licensed under the GNU LGPL.
+ */
+
+#include "qemu/osdep.h"
+#include "hw/ptimer.h"
+#include "migration/vmstate.h"
+#include "qemu/host-utils.h"
+#include "sysemu/replay.h"
+#include "sysemu/cpu-timers.h"
+#include "sysemu/qtest.h"
+#include "block/aio.h"
+#include "hw/clock.h"
+
+#define DELTA_ADJUST     1
+#define DELTA_NO_ADJUST -1
+
+struct ptimer_state
+{
+    uint8_t enabled; /* 0 = disabled, 1 = periodic, 2 = oneshot.  */
+    uint64_t limit;
+    uint64_t delta;
+    uint32_t period_frac;
+    int64_t period;
+    int64_t last_event;
+    int64_t next_event;
+    uint8_t policy_mask;
+    QEMUTimer *timer;
+    ptimer_cb callback;
+    void *callback_opaque;
+    /*
+     * These track whether we're in a transaction block, and if we
+     * need to do a timer reload when the block finishes. They don't
+     * need to be migrated because migration can never happen in the
+     * middle of a transaction block.
+     */
+    bool in_transaction;
+    bool need_reload;
+};
+
+/* Use a bottom-half routine to avoid reentrancy issues.  */
+static void ptimer_trigger(ptimer_state *s)
+{
+    s->callback(s->callback_opaque);
+}
+
+static void ptimer_reload(ptimer_state *s, int delta_adjust)
+{
+    uint32_t period_frac;
+    uint64_t period;
+    uint64_t delta;
+    bool suppress_trigger = false;
+
+    /*
+     * Note that if delta_adjust is 0 then we must be here because of
+     * a count register write or timer start, not because of timer expiry.
+     * In that case the policy might require us to suppress the timer trigger
+     * that we would otherwise generate for a zero delta.
+     */
+    if (delta_adjust == 0 &&
+        (s->policy_mask & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT)) {
+        suppress_trigger = true;
+    }
+    if (s->delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)
+        && !suppress_trigger) {
+        ptimer_trigger(s);
+    }
+
+    /*
+     * Note that ptimer_trigger() might call the device callback function,
+     * which can then modify timer state, so we must not cache any fields
+     * from ptimer_state until after we have called it.
+     */
+    delta = s->delta;
+    period = s->period;
+    period_frac = s->period_frac;
+
+    if (delta == 0 && !(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_RELOAD)) {
+        delta = s->delta = s->limit;
+    }
+
+    if (s->period == 0) {
+        if (!qtest_enabled()) {
+            fprintf(stderr, "Timer with period zero, disabling\n");
+        }
+        timer_del(s->timer);
+        s->enabled = 0;
+        return;
+    }
+
+    if (s->policy_mask & PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD) {
+        if (delta_adjust != DELTA_NO_ADJUST) {
+            delta += delta_adjust;
+        }
+    }
+
+    if (delta == 0 && (s->policy_mask & PTIMER_POLICY_CONTINUOUS_TRIGGER)) {
+        if (s->enabled == 1 && s->limit == 0) {
+            delta = 1;
+        }
+    }
+
+    if (delta == 0 && (s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)) {
+        if (delta_adjust != DELTA_NO_ADJUST) {
+            delta = 1;
+        }
+    }
+
+    if (delta == 0 && (s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_RELOAD)) {
+        if (s->enabled == 1 && s->limit != 0) {
+            delta = 1;
+        }
+    }
+
+    if (delta == 0) {
+        if (s->enabled == 0) {
+            /* trigger callback disabled the timer already */
+            return;
+        }
+        if (!qtest_enabled()) {
+            fprintf(stderr, "Timer with delta zero, disabling\n");
+        }
+        timer_del(s->timer);
+        s->enabled = 0;
+        return;
+    }
+
+    /*
+     * Artificially limit timeout rate to something
+     * achievable under QEMU.  Otherwise, QEMU spends all
+     * its time generating timer interrupts, and there
+     * is no forward progress.
+     * About ten microseconds is the fastest that really works
+     * on the current generation of host machines.
+     */
+
+    if (s->enabled == 1 && (delta * period < 10000) &&
+        !icount_enabled() && !qtest_enabled()) {
+        period = 10000 / delta;
+        period_frac = 0;
+    }
+
+    s->last_event = s->next_event;
+    s->next_event = s->last_event + delta * period;
+    if (period_frac) {
+        s->next_event += ((int64_t)period_frac * delta) >> 32;
+    }
+    timer_mod(s->timer, s->next_event);
+}
+
+static void ptimer_tick(void *opaque)
+{
+    ptimer_state *s = (ptimer_state *)opaque;
+    bool trigger = true;
+
+    /*
+     * We perform all the tick actions within a begin/commit block
+     * because the callback function that ptimer_trigger() calls
+     * might make calls into the ptimer APIs that provoke another
+     * trigger, and we want that to cause the callback function
+     * to be called iteratively, not recursively.
+     */
+    ptimer_transaction_begin(s);
+
+    if (s->enabled == 2) {
+        s->delta = 0;
+        s->enabled = 0;
+    } else {
+        int delta_adjust = DELTA_ADJUST;
+
+        if (s->delta == 0 || s->limit == 0) {
+            /* If a "continuous trigger" policy is not used and limit == 0,
+               we should error out. delta == 0 means that this tick is
+               caused by a "no immediate reload" policy, so it shouldn't
+               be adjusted.  */
+            delta_adjust = DELTA_NO_ADJUST;
+        }
+
+        if (!(s->policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)) {
+            /* Avoid re-trigger on deferred reload if "no immediate trigger"
+               policy isn't used.  */
+            trigger = (delta_adjust == DELTA_ADJUST);
+        }
+
+        s->delta = s->limit;
+
+        ptimer_reload(s, delta_adjust);
+    }
+
+    if (trigger) {
+        ptimer_trigger(s);
+    }
+
+    ptimer_transaction_commit(s);
+}
+
+uint64_t ptimer_get_count(ptimer_state *s)
+{
+    uint64_t counter;
+
+    if (s->enabled && s->delta != 0) {
+        int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+        int64_t next = s->next_event;
+        int64_t last = s->last_event;
+        bool expired = (now - next >= 0);
+        bool oneshot = (s->enabled == 2);
+
+        /* Figure out the current counter value.  */
+        if (expired) {
+            /* Prevent timer underflowing if it should already have
+               triggered.  */
+            counter = 0;
+        } else {
+            uint64_t rem;
+            uint64_t div;
+            int clz1, clz2;
+            int shift;
+            uint32_t period_frac = s->period_frac;
+            uint64_t period = s->period;
+
+            if (!oneshot && (s->delta * period < 10000) &&
+                !icount_enabled() && !qtest_enabled()) {
+                period = 10000 / s->delta;
+                period_frac = 0;
+            }
+
+            /* We need to divide time by period, where time is stored in
+               rem (64-bit integer) and period is stored in period/period_frac
+               (64.32 fixed point).
+
+               Doing full precision division is hard, so scale values and
+               do a 64-bit division.  The result should be rounded down,
+               so that the rounding error never causes the timer to go
+               backwards.
+            */
+
+            rem = next - now;
+            div = period;
+
+            clz1 = clz64(rem);
+            clz2 = clz64(div);
+            shift = clz1 < clz2 ? clz1 : clz2;
+
+            rem <<= shift;
+            div <<= shift;
+            if (shift >= 32) {
+                div |= ((uint64_t)period_frac << (shift - 32));
+            } else {
+                if (shift != 0)
+                    div |= (period_frac >> (32 - shift));
+                /* Look at remaining bits of period_frac and round div up if 
+                   necessary.  */
+                if ((uint32_t)(period_frac << shift))
+                    div += 1;
+            }
+            counter = rem / div;
+
+            if (s->policy_mask & PTIMER_POLICY_WRAP_AFTER_ONE_PERIOD) {
+                /* Before wrapping around, timer should stay with counter = 0
+                   for a one period.  */
+                if (!oneshot && s->delta == s->limit) {
+                    if (now == last) {
+                        /* Counter == delta here, check whether it was
+                           adjusted and if it was, then right now it is
+                           that "one period".  */
+                        if (counter == s->limit + DELTA_ADJUST) {
+                            return 0;
+                        }
+                    } else if (counter == s->limit) {
+                        /* Since the counter is rounded down and now != last,
+                           the counter == limit means that delta was adjusted
+                           by +1 and right now it is that adjusted period.  */
+                        return 0;
+                    }
+                }
+            }
+        }
+
+        if (s->policy_mask & PTIMER_POLICY_NO_COUNTER_ROUND_DOWN) {
+            /* If now == last then delta == limit, i.e. the counter already
+               represents the correct value. It would be rounded down a 1ns
+               later.  */
+            if (now != last) {
+                counter += 1;
+            }
+        }
+    } else {
+        counter = s->delta;
+    }
+    return counter;
+}
+
+void ptimer_set_count(ptimer_state *s, uint64_t count)
+{
+    assert(s->in_transaction);
+    s->delta = count;
+    if (s->enabled) {
+        s->need_reload = true;
+    }
+}
+
+void ptimer_run(ptimer_state *s, int oneshot)
+{
+    bool was_disabled = !s->enabled;
+
+    assert(s->in_transaction);
+
+    if (was_disabled && s->period == 0) {
+        if (!qtest_enabled()) {
+            fprintf(stderr, "Timer with period zero, disabling\n");
+        }
+        return;
+    }
+    s->enabled = oneshot ? 2 : 1;
+    if (was_disabled) {
+        s->need_reload = true;
+    }
+}
+
+/* Pause a timer.  Note that this may cause it to "lose" time, even if it
+   is immediately restarted.  */
+void ptimer_stop(ptimer_state *s)
+{
+    assert(s->in_transaction);
+
+    if (!s->enabled)
+        return;
+
+    s->delta = ptimer_get_count(s);
+    timer_del(s->timer);
+    s->enabled = 0;
+    s->need_reload = false;
+}
+
+/* Set counter increment interval in nanoseconds.  */
+void ptimer_set_period(ptimer_state *s, int64_t period)
+{
+    assert(s->in_transaction);
+    s->delta = ptimer_get_count(s);
+    s->period = period;
+    s->period_frac = 0;
+    if (s->enabled) {
+        s->need_reload = true;
+    }
+}
+
+/* Set counter increment interval from a Clock */
+void ptimer_set_period_from_clock(ptimer_state *s, const Clock *clk,
+                                  unsigned int divisor)
+{
+    /*
+     * The raw clock period is a 64-bit value in units of 2^-32 ns;
+     * put another way it's a 32.32 fixed-point ns value. Our internal
+     * representation of the period is 64.32 fixed point ns, so
+     * the conversion is simple.
+     */
+    uint64_t raw_period = clock_get(clk);
+    uint64_t period_frac;
+
+    assert(s->in_transaction);
+    s->delta = ptimer_get_count(s);
+    s->period = extract64(raw_period, 32, 32);
+    period_frac = extract64(raw_period, 0, 32);
+    /*
+     * divisor specifies a possible frequency divisor between the
+     * clock and the timer, so it is a multiplier on the period.
+     * We do the multiply after splitting the raw period out into
+     * period and frac to avoid having to do a 32*64->96 multiply.
+     */
+    s->period *= divisor;
+    period_frac *= divisor;
+    s->period += extract64(period_frac, 32, 32);
+    s->period_frac = (uint32_t)period_frac;
+
+    if (s->enabled) {
+        s->need_reload = true;
+    }
+}
+
+/* Set counter frequency in Hz.  */
+void ptimer_set_freq(ptimer_state *s, uint32_t freq)
+{
+    assert(s->in_transaction);
+    s->delta = ptimer_get_count(s);
+    s->period = 1000000000ll / freq;
+    s->period_frac = (1000000000ll << 32) / freq;
+    if (s->enabled) {
+        s->need_reload = true;
+    }
+}
+
+/* Set the initial countdown value.  If reload is nonzero then also set
+   count = limit.  */
+void ptimer_set_limit(ptimer_state *s, uint64_t limit, int reload)
+{
+    assert(s->in_transaction);
+    s->limit = limit;
+    if (reload)
+        s->delta = limit;
+    if (s->enabled && reload) {
+        s->need_reload = true;
+    }
+}
+
+uint64_t ptimer_get_limit(ptimer_state *s)
+{
+    return s->limit;
+}
+
+void ptimer_transaction_begin(ptimer_state *s)
+{
+    assert(!s->in_transaction);
+    s->in_transaction = true;
+    s->need_reload = false;
+}
+
+void ptimer_transaction_commit(ptimer_state *s)
+{
+    assert(s->in_transaction);
+    /*
+     * We must loop here because ptimer_reload() can call the callback
+     * function, which might then update ptimer state in a way that
+     * means we need to do another reload and possibly another callback.
+     * A disabled timer never needs reloading (and if we don't check
+     * this then we loop forever if ptimer_reload() disables the timer).
+     */
+    while (s->need_reload && s->enabled) {
+        s->need_reload = false;
+        s->next_event = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+        ptimer_reload(s, 0);
+    }
+    /* Now we've finished reload we can leave the transaction block. */
+    s->in_transaction = false;
+}
+
+const VMStateDescription vmstate_ptimer = {
+    .name = "ptimer",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT8(enabled, ptimer_state),
+        VMSTATE_UINT64(limit, ptimer_state),
+        VMSTATE_UINT64(delta, ptimer_state),
+        VMSTATE_UINT32(period_frac, ptimer_state),
+        VMSTATE_INT64(period, ptimer_state),
+        VMSTATE_INT64(last_event, ptimer_state),
+        VMSTATE_INT64(next_event, ptimer_state),
+        VMSTATE_TIMER_PTR(timer, ptimer_state),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+ptimer_state *ptimer_init(ptimer_cb callback, void *callback_opaque,
+                          uint8_t policy_mask)
+{
+    ptimer_state *s;
+
+    /* The callback function is mandatory. */
+    assert(callback);
+
+    s = g_new0(ptimer_state, 1);
+    s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, ptimer_tick, s);
+    s->policy_mask = policy_mask;
+    s->callback = callback;
+    s->callback_opaque = callback_opaque;
+
+    /*
+     * These two policies are incompatible -- trigger-on-decrement implies
+     * a timer trigger when the count becomes 0, but no-immediate-trigger
+     * implies a trigger when the count stops being 0.
+     */
+    assert(!((policy_mask & PTIMER_POLICY_TRIGGER_ONLY_ON_DECREMENT) &&
+             (policy_mask & PTIMER_POLICY_NO_IMMEDIATE_TRIGGER)));
+    return s;
+}
+
+void ptimer_free(ptimer_state *s)
+{
+    timer_free(s->timer);
+    g_free(s);
+}