adb: keep track of devices with pending data

Add a new pending variable to ADBBusState which is a bitmask indicating which
ADB devices have data to send. Update the bitmask every time that an ADB
request is executed.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Tested-by: Finn Thain <fthain@telegraphics.com.au>
Acked-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20200623204936.24064-13-mark.cave-ayland@ilande.co.uk>

2 files changed, 16 insertions, 1 deletions

diff --git a/hw/input/adb.c b/hw/input/adb.c
index bb36ce6fad..c1adb21e6b 100644
--- a/hw/input/adb.c
+++ b/hw/input/adb.c
@@ -41,6 +41,7 @@ static void adb_device_reset(ADBDevice *d)
 int adb_request(ADBBusState *s, uint8_t *obuf, const uint8_t *buf, int len)
 {
     ADBDevice *d;
+    ADBDeviceClass *adc;
     int devaddr, cmd, i;
 
     cmd = buf[0] & 0xf;
@@ -51,14 +52,27 @@ int adb_request(ADBBusState *s, uint8_t *obuf, const uint8_t *buf, int len)
         }
         return 0;
     }
+
+    s->pending = 0;
+    for (i = 0; i < s->nb_devices; i++) {
+        d = s->devices[i];
+        adc = ADB_DEVICE_GET_CLASS(d);
+
+        if (adc->devhasdata(d)) {
+            s->pending |= (1 << d->devaddr);
+        }
+    }
+
     devaddr = buf[0] >> 4;
     for (i = 0; i < s->nb_devices; i++) {
         d = s->devices[i];
+        adc = ADB_DEVICE_GET_CLASS(d);
+
         if (d->devaddr == devaddr) {
-            ADBDeviceClass *adc = ADB_DEVICE_GET_CLASS(d);
             return adc->devreq(d, obuf, buf, len);
         }
     }
+
     return ADB_RET_NOTPRESENT;
 }
 
diff --git a/include/hw/input/adb.h b/include/hw/input/adb.h
index 9b80204e43..f1bc358d8e 100644
--- a/include/hw/input/adb.h
+++ b/include/hw/input/adb.h
@@ -76,6 +76,7 @@ struct ADBBusState {
     /*< public >*/
 
     ADBDevice *devices[MAX_ADB_DEVICES];
+    uint16_t pending;
     int nb_devices;
     int poll_index;