1 files changed, 109 insertions, 0 deletions
diff --git a/hw/mips_timer.c b/hw/mips_timer.c
new file mode 100644
index 0000000..bb3c3e4
--- /dev/null
+++ b/hw/mips_timer.c
@@ -0,0 +1,109 @@
+#include "hw.h"
+#include "mips.h"
+#include "qemu-timer.h"
+
+#define TIMER_FREQ	100 * 1000 * 1000
+
+/* XXX: do not use a global */
+uint32_t cpu_mips_get_random (CPUState *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 */
+uint32_t cpu_mips_get_count (CPUState *env)
+{
+    if (env->CP0_Cause & (1 << CP0Ca_DC))
+        return env->CP0_Count;
+    else
+        return env->CP0_Count +
+            (uint32_t)muldiv64(qemu_get_clock(vm_clock),
+                               TIMER_FREQ, get_ticks_per_sec());
+}
+
+static void cpu_mips_timer_update(CPUState *env)
+{
+    uint64_t now, next;
+    uint32_t wait;
+
+    now = qemu_get_clock(vm_clock);
+    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);
+    qemu_mod_timer(env->timer, next);
+}
+
+void cpu_mips_store_count (CPUState *env, uint32_t count)
+{
+    if (env->CP0_Cause & (1 << CP0Ca_DC))
+        env->CP0_Count = count;
+    else {
+        /* Store new count register */
+        env->CP0_Count =
+            count - (uint32_t)muldiv64(qemu_get_clock(vm_clock),
+                                       TIMER_FREQ, get_ticks_per_sec());
+        /* Update timer timer */
+        cpu_mips_timer_update(env);
+    }
+}
+
+void cpu_mips_store_compare (CPUState *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(CPUState *env)
+{
+    cpu_mips_store_count(env, env->CP0_Count);
+}
+
+void cpu_mips_stop_count(CPUState *env)
+{
+    /* Store the current value */
+    env->CP0_Count += (uint32_t)muldiv64(qemu_get_clock(vm_clock),
+                                         TIMER_FREQ, get_ticks_per_sec());
+}
+
+static void mips_timer_cb (void *opaque)
+{
+    CPUState *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_update(env);
+    env->CP0_Count--;
+    if (env->insn_flags & ISA_MIPS32R2)
+        env->CP0_Cause |= 1 << CP0Ca_TI;
+    qemu_irq_raise(env->irq[(env->CP0_IntCtl >> CP0IntCtl_IPTI) & 0x7]);
+}
+
+void cpu_mips_clock_init (CPUState *env)
+{
+    env->timer = qemu_new_timer(vm_clock, &mips_timer_cb, env);
+    env->CP0_Compare = 0;
+    cpu_mips_store_count(env, 1);
+}