[C,v2,02/10] ADB: VIA probes ADB bus when it is idle

diff --git a/hw/input/adb-kbd.c b/hw/input/adb-kbd.c
index b026e9d49f..f439e106bb 100644
--- a/hw/input/adb-kbd.c
+++ b/hw/input/adb-kbd.c
@@ -195,6 +195,10 @@  static int adb_kbd_poll(ADBDevice *d, uint8_t *obuf)
     int keycode;
     int olen;
 
+    if (obuf == NULL) {
+        return s->count;
+    }
+
     olen = 0;
     if (s->count == 0) {
         return 0;
diff --git a/hw/input/adb-mouse.c b/hw/input/adb-mouse.c
index 83833b0035..7615c252d5 100644
--- a/hw/input/adb-mouse.c
+++ b/hw/input/adb-mouse.c
@@ -73,6 +73,10 @@  static int adb_mouse_poll(ADBDevice *d, uint8_t *obuf)
         return 0;
     }
 
+    if (obuf == NULL) {
+        return 2;
+    }
+
     dx = s->dx;
     if (dx < -63) {
         dx = -63;
diff --git a/hw/input/adb.c b/hw/input/adb.c
index bbb40aeef1..99852879d8 100644
--- a/hw/input/adb.c
+++ b/hw/input/adb.c
@@ -25,6 +25,17 @@ 
 #include "hw/input/adb.h"
 #include "adb-internal.h"
 
+#define ADB_POLL_FREQ 50
+
+/* Apple Macintosh Family Hardware Refenece
+ * Table 19-10 ADB transaction states
+ */
+
+#define STATE_NEW       0
+#define STATE_EVEN      1
+#define STATE_ODD       2
+#define STATE_IDLE      3
+
 /* error codes */
 #define ADB_RET_NOTPRESENT (-2)
 
@@ -84,6 +95,110 @@  int adb_poll(ADBBusState *s, uint8_t *obuf, uint16_t poll_mask)
     return olen;
 }
 
+int adb_via_poll(ADBBusState *adb, int state, uint8_t *data)
+{
+    if (state != STATE_IDLE) {
+        return 0;
+    }
+    if (adb->data_in_size < adb->data_in_index) {
+        return 0;
+    }
+    if (adb->data_out_index != 0) {
+        return 0;
+    }
+    adb->data_in_index = 0;
+    adb->data_out_index = 0;
+    adb->data_in_size = adb_poll(adb, adb->data_in, 0xffff);
+    if (adb->data_in_size) {
+        *data = adb->data_in[adb->data_in_index++];
+        qemu_irq_raise(adb->data_ready);
+    }
+    return adb->data_in_size;
+}
+
+int adb_send(ADBBusState *adb, int state, uint8_t data)
+{
+    switch (state) {
+    case STATE_NEW:
+        adb->data_out_index = 0;
+        break;
+    case STATE_EVEN:
+        if ((adb->data_out_index & 1) == 0) {
+            return 0;
+        }
+        break;
+    case STATE_ODD:
+        if (adb->data_out_index & 1) {
+            return 0;
+        }
+        break;
+    case STATE_IDLE:
+        return 0;
+    }
+    adb->data_out[adb->data_out_index++] = data;
+    qemu_irq_raise(adb->data_ready);
+    return 1;
+}
+
+int adb_receive(ADBBusState *adb, int state, uint8_t *data)
+{
+    switch (state) {
+    case STATE_NEW:
+        return 0;
+    case STATE_EVEN:
+        if (adb->data_in_size <= 0) {
+            qemu_irq_raise(adb->data_ready);
+            return 0;
+        }
+        if (adb->data_in_index >= adb->data_in_size) {
+            *data = 0;
+            qemu_irq_raise(adb->data_ready);
+            return 1;
+        }
+        if ((adb->data_in_index & 1) == 0) {
+            return 0;
+        }
+        break;
+    case STATE_ODD:
+        if (adb->data_in_size <= 0) {
+            qemu_irq_raise(adb->data_ready);
+            return 0;
+        }
+        if (adb->data_in_index >= adb->data_in_size) {
+            *data = 0;
+            qemu_irq_raise(adb->data_ready);
+            return 1;
+        }
+        if (adb->data_in_index & 1) {
+            return 0;
+        }
+        break;
+    case STATE_IDLE:
+        if (adb->data_out_index == 0) {
+            return 0;
+        }
+        adb->data_in_size = adb_request(adb, adb->data_in,
+                                        adb->data_out, adb->data_out_index);
+        adb->data_out_index = 0;
+        adb->data_in_index = 0;
+        if (adb->data_in_size < 0) {
+            *data = 0xff;
+            qemu_irq_raise(adb->data_ready);
+            return -1;
+        }
+        if (adb->data_in_size == 0) {
+            return 0;
+        }
+        break;
+    }
+    *data = adb->data_in[adb->data_in_index++];
+    qemu_irq_raise(adb->data_ready);
+    if (*data == 0xff || *data == 0) {
+        return 0;
+    }
+    return 1;
+}
+
 static const TypeInfo adb_bus_type_info = {
     .name = TYPE_ADB_BUS,
     .parent = TYPE_BUS,
diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
index 586477ca9e..200121f798 100644
--- a/hw/misc/mac_via.c
+++ b/hw/misc/mac_via.c
@@ -424,6 +424,53 @@  static void via1_rtc_update(MacVIAState *m)
     }
 }
 
+static void via1_adb_update(MacVIAState *m)
+{
+    MOS6522Q800VIA1State *v1s = MOS6522_Q800_VIA1(&m->mos6522_via1);
+    MOS6522State *s = MOS6522(v1s);
+    int state;
+    int ret;
+
+    state = (s->b & VIA1B_vADB_StateMask) >> VIA1B_vADB_StateShift;
+
+    if (s->acr & VIA1ACR_vShiftOut) {
+        /* output mode */
+        ret = adb_send(&m->adb_bus, state, s->sr);
+        if (ret > 0) {
+            s->b &= ~VIA1B_vADBInt;
+        } else {
+            s->b |= VIA1B_vADBInt;
+        }
+    } else {
+        /* input mode */
+        ret = adb_receive(&m->adb_bus, state, &s->sr);
+        if (ret > 0 && s->sr != 0xff) {
+            s->b &= ~VIA1B_vADBInt;
+        } else {
+            s->b |= VIA1B_vADBInt;
+        }
+    }
+}
+
+static void via_adb_poll(void *opaque)
+{
+    MacVIAState *m = opaque;
+    MOS6522Q800VIA1State *v1s = MOS6522_Q800_VIA1(&m->mos6522_via1);
+    MOS6522State *s = MOS6522(v1s);
+    int state;
+
+    if (s->b & VIA1B_vADBInt) {
+        state = (s->b & VIA1B_vADB_StateMask) >> VIA1B_vADB_StateShift;
+        if (adb_via_poll(&m->adb_bus, state, &s->sr)) {
+            s->b &= ~VIA1B_vADBInt;
+        }
+    }
+
+    timer_mod(m->adb_poll_timer,
+              qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+              (NANOSECONDS_PER_SECOND / VIA_ADB_POLL_FREQ));
+}
+
 static uint64_t mos6522_q800_via1_read(void *opaque, hwaddr addr, unsigned size)
 {
     MOS6522Q800VIA1State *s = opaque;
@@ -486,6 +533,10 @@  static void mac_via_reset(DeviceState *dev)
 {
     MacVIAState *m = MAC_VIA(dev);
 
+    timer_mod(m->adb_poll_timer,
+              qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
+              (NANOSECONDS_PER_SECOND / VIA_ADB_POLL_FREQ));
+
     timer_mod(m->VBL_timer, (qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + 16630)
               / 16630 * 16630);
 
@@ -504,6 +555,7 @@  static void mac_via_realize(DeviceState *dev, Error **errp)
 
     qemu_get_timedate(&tm, 0);
     m->tick_offset = (uint32_t)mktimegm(&tm) + RTC_OFFSET;
+    m->adb_poll_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, via_adb_poll, m);
 }
 
 static void mac_via_init(Object *obj)
@@ -553,6 +605,9 @@  static void mac_via_init(Object *obj)
     /* ADB */
     qbus_create_inplace((BusState *)&m->adb_bus, sizeof(m->adb_bus),
                         TYPE_ADB_BUS, DEVICE(obj), "adb.0");
+
+    m->adb_bus.data_ready = qdev_get_gpio_in_named(DEVICE(obj), "via1-irq",
+                                                   VIA1_IRQ_ADB_READY_BIT);
 }
 
 static void mac_via_class_init(ObjectClass *oc, void *data)
@@ -579,6 +634,7 @@  static void mos6522_q800_via1_portB_write(MOS6522State *s)
     MacVIAState *m = container_of(v1s, MacVIAState, mos6522_via1);
 
     via1_rtc_update(m);
+    via1_adb_update(m);
 
     v1s->last_b = s->b;
 }
diff --git a/include/hw/input/adb.h b/include/hw/input/adb.h
index f99d478252..1888c5aab7 100644
--- a/include/hw/input/adb.h
+++ b/include/hw/input/adb.h
@@ -76,6 +76,12 @@  struct ADBBusState {
     ADBDevice *devices[MAX_ADB_DEVICES];
     int nb_devices;
     int poll_index;
+    qemu_irq data_ready;
+    int data_in_size;
+    int data_in_index;
+    int data_out_index;
+    uint8_t data_in[128];
+    uint8_t data_out[16];
 };
 
 int adb_request(ADBBusState *s, uint8_t *buf_out,
@@ -85,4 +91,8 @@  int adb_poll(ADBBusState *s, uint8_t *buf_out, uint16_t poll_mask);
 #define TYPE_ADB_KEYBOARD "adb-keyboard"
 #define TYPE_ADB_MOUSE "adb-mouse"
 
+int adb_via_poll(ADBBusState *s, int state, uint8_t *data);
+int adb_send(ADBBusState *adb, int state, uint8_t data);
+int adb_receive(ADBBusState *adb, int state, uint8_t *data);
+
 #endif /* ADB_H */
diff --git a/include/hw/misc/mac_via.h b/include/hw/misc/mac_via.h
index a3a972ccc5..85d8715b12 100644
--- a/include/hw/misc/mac_via.h
+++ b/include/hw/misc/mac_via.h
@@ -96,6 +96,7 @@  typedef struct MacVIAState {
 
     /* ADB */
     ADBBusState adb_bus;
+    QEMUTimer *adb_poll_timer;
 
     /* external timers */
     QEMUTimer *one_second_timer;