target-xtensa: implement interrupt option

See ISA, 4.4.6 (interrupt option), 4.4.7 (high priority interrupt
option) and 4.4.8 (timer interrupt option) for details.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

1 files changed, 96 insertions, 0 deletions

diff --git a/hw/xtensa_pic.c b/hw/xtensa_pic.c
index 91a5445f42..3033ae214a 100644
--- a/hw/xtensa_pic.c
+++ b/hw/xtensa_pic.c
@@ -27,6 +27,8 @@
 
 #include "hw.h"
 #include "pc.h"
+#include "qemu-log.h"
+#include "qemu-timer.h"
 
 /* Stub functions for hardware that doesn't exist.  */
 void pic_info(Monitor *mon)
@@ -36,3 +38,97 @@ void pic_info(Monitor *mon)
 void irq_info(Monitor *mon)
 {
 }
+
+void xtensa_advance_ccount(CPUState *env, uint32_t d)
+{
+    uint32_t old_ccount = env->sregs[CCOUNT];
+
+    env->sregs[CCOUNT] += d;
+
+    if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT)) {
+        int i;
+        for (i = 0; i < env->config->nccompare; ++i) {
+            if (env->sregs[CCOMPARE + i] - old_ccount <= d) {
+                xtensa_timer_irq(env, i, 1);
+            }
+        }
+    }
+}
+
+void check_interrupts(CPUState *env)
+{
+    int minlevel = xtensa_get_cintlevel(env);
+    uint32_t int_set_enabled = env->sregs[INTSET] & env->sregs[INTENABLE];
+    int level;
+
+    /* If the CPU is halted advance CCOUNT according to the vm_clock time
+     * elapsed since the moment when it was advanced last time.
+     */
+    if (env->halted) {
+        int64_t now = qemu_get_clock_ns(vm_clock);
+
+        xtensa_advance_ccount(env,
+                muldiv64(now - env->halt_clock,
+                    env->config->clock_freq_khz, 1000000));
+        env->halt_clock = now;
+    }
+    for (level = env->config->nlevel; level > minlevel; --level) {
+        if (env->config->level_mask[level] & int_set_enabled) {
+            env->pending_irq_level = level;
+            cpu_interrupt(env, CPU_INTERRUPT_HARD);
+            qemu_log_mask(CPU_LOG_INT,
+                    "%s level = %d, cintlevel = %d, "
+                    "pc = %08x, a0 = %08x, ps = %08x, "
+                    "intset = %08x, intenable = %08x, "
+                    "ccount = %08x\n",
+                    __func__, level, xtensa_get_cintlevel(env),
+                    env->pc, env->regs[0], env->sregs[PS],
+                    env->sregs[INTSET], env->sregs[INTENABLE],
+                    env->sregs[CCOUNT]);
+            return;
+        }
+    }
+    env->pending_irq_level = 0;
+    cpu_reset_interrupt(env, CPU_INTERRUPT_HARD);
+}
+
+static void xtensa_set_irq(void *opaque, int irq, int active)
+{
+    CPUState *env = opaque;
+
+    if (irq >= env->config->ninterrupt) {
+        qemu_log("%s: bad IRQ %d\n", __func__, irq);
+    } else {
+        uint32_t irq_bit = 1 << irq;
+
+        if (active) {
+            env->sregs[INTSET] |= irq_bit;
+        } else if (env->config->interrupt[irq].inttype == INTTYPE_LEVEL) {
+            env->sregs[INTSET] &= ~irq_bit;
+        }
+
+        check_interrupts(env);
+    }
+}
+
+void xtensa_timer_irq(CPUState *env, uint32_t id, uint32_t active)
+{
+    qemu_set_irq(env->irq_inputs[env->config->timerint[id]], active);
+}
+
+static void xtensa_ccompare_cb(void *opaque)
+{
+    CPUState *env = opaque;
+    xtensa_advance_ccount(env, env->wake_ccount - env->sregs[CCOUNT]);
+}
+
+void xtensa_irq_init(CPUState *env)
+{
+    env->irq_inputs = (void **)qemu_allocate_irqs(
+            xtensa_set_irq, env, env->config->ninterrupt);
+    if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT) &&
+            env->config->nccompare > 0) {
+        env->ccompare_timer =
+            qemu_new_timer_ns(vm_clock, &xtensa_ccompare_cb, env);
+    }
+}