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-rw-r--r--qemu/hw/mips/cputimer.c157
1 files changed, 157 insertions, 0 deletions
diff --git a/qemu/hw/mips/cputimer.c b/qemu/hw/mips/cputimer.c
new file mode 100644
index 000000000..577c9aeab
--- /dev/null
+++ b/qemu/hw/mips/cputimer.c
@@ -0,0 +1,157 @@
+/*
+ * QEMU MIPS timer support
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "hw/hw.h"
+#include "hw/mips/cpudevs.h"
+#include "qemu/timer.h"
+#include "sysemu/kvm.h"
+
+#define TIMER_FREQ 100 * 1000 * 1000
+
+/* XXX: do not use a global */
+uint32_t cpu_mips_get_random (CPUMIPSState *env)
+{
+ static uint32_t lfsr = 1;
+ static uint32_t prev_idx = 0;
+ uint32_t idx;
+ /* Don't return same value twice, so get another value */
+ do {
+ lfsr = (lfsr >> 1) ^ (-(lfsr & 1u) & 0xd0000001u);
+ idx = lfsr % (env->tlb->nb_tlb - env->CP0_Wired) + env->CP0_Wired;
+ } while (idx == prev_idx);
+ prev_idx = idx;
+ return idx;
+}
+
+/* MIPS R4K timer */
+static void cpu_mips_timer_update(CPUMIPSState *env)
+{
+ uint64_t now, next;
+ uint32_t wait;
+
+ now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ wait = env->CP0_Compare - env->CP0_Count -
+ (uint32_t)muldiv64(now, TIMER_FREQ, get_ticks_per_sec());
+ next = now + muldiv64(wait, get_ticks_per_sec(), TIMER_FREQ);
+ timer_mod(env->timer, next);
+}
+
+/* Expire the timer. */
+static void cpu_mips_timer_expire(CPUMIPSState *env)
+{
+ cpu_mips_timer_update(env);
+ if (env->insn_flags & ISA_MIPS32R2) {
+ env->CP0_Cause |= 1 << CP0Ca_TI;
+ }
+ qemu_irq_raise(env->irq[(env->CP0_IntCtl >> CP0IntCtl_IPTI) & 0x7]);
+}
+
+uint32_t cpu_mips_get_count (CPUMIPSState *env)
+{
+ if (env->CP0_Cause & (1 << CP0Ca_DC)) {
+ return env->CP0_Count;
+ } else {
+ uint64_t now;
+
+ now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ if (timer_pending(env->timer)
+ && timer_expired(env->timer, now)) {
+ /* The timer has already expired. */
+ cpu_mips_timer_expire(env);
+ }
+
+ return env->CP0_Count +
+ (uint32_t)muldiv64(now, TIMER_FREQ, get_ticks_per_sec());
+ }
+}
+
+void cpu_mips_store_count (CPUMIPSState *env, uint32_t count)
+{
+ /*
+ * This gets called from cpu_state_reset(), potentially before timer init.
+ * So env->timer may be NULL, which is also the case with KVM enabled so
+ * treat timer as disabled in that case.
+ */
+ if (env->CP0_Cause & (1 << CP0Ca_DC) || !env->timer)
+ env->CP0_Count = count;
+ else {
+ /* Store new count register */
+ env->CP0_Count =
+ count - (uint32_t)muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
+ TIMER_FREQ, get_ticks_per_sec());
+ /* Update timer timer */
+ cpu_mips_timer_update(env);
+ }
+}
+
+void cpu_mips_store_compare (CPUMIPSState *env, uint32_t value)
+{
+ env->CP0_Compare = value;
+ if (!(env->CP0_Cause & (1 << CP0Ca_DC)))
+ cpu_mips_timer_update(env);
+ if (env->insn_flags & ISA_MIPS32R2)
+ env->CP0_Cause &= ~(1 << CP0Ca_TI);
+ qemu_irq_lower(env->irq[(env->CP0_IntCtl >> CP0IntCtl_IPTI) & 0x7]);
+}
+
+void cpu_mips_start_count(CPUMIPSState *env)
+{
+ cpu_mips_store_count(env, env->CP0_Count);
+}
+
+void cpu_mips_stop_count(CPUMIPSState *env)
+{
+ /* Store the current value */
+ env->CP0_Count += (uint32_t)muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
+ TIMER_FREQ, get_ticks_per_sec());
+}
+
+static void mips_timer_cb (void *opaque)
+{
+ CPUMIPSState *env;
+
+ env = opaque;
+#if 0
+ qemu_log("%s\n", __func__);
+#endif
+
+ if (env->CP0_Cause & (1 << CP0Ca_DC))
+ return;
+
+ /* ??? This callback should occur when the counter is exactly equal to
+ the comparator value. Offset the count by one to avoid immediately
+ retriggering the callback before any virtual time has passed. */
+ env->CP0_Count++;
+ cpu_mips_timer_expire(env);
+ env->CP0_Count--;
+}
+
+void cpu_mips_clock_init (CPUMIPSState *env)
+{
+ /*
+ * If we're in KVM mode, don't create the periodic timer, that is handled in
+ * kernel.
+ */
+ if (!kvm_enabled()) {
+ env->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &mips_timer_cb, env);
+ }
+}