macintosh/via-macii: Handle poll replies correctly

Userspace applications may use /dev/adb to send Talk requests. Such
requests always have req->reply_expected == 1. The same is true of Talk
requests sent by the kernel, except for poll requests queued internally
by the via-macii driver. Those requests have req->reply_expected == 0.

Consequently, poll reply packets get treated like autopoll reply packets.
(It doesn't make sense to try to distinguish them.) Always enter 'reading'
state after a poll request, so that the reply gets collected and passed
to adb_input(), and none go missing.

All Talk replies passed to adb_input() come from polling or autopolling,
so call adb_input() with the autopoll parameter set to 1.

Fixes: d95fd5fce8 ("m68k: Mac II ADB fixes") # v5.0+
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/754cddfa045e5bfa53e5da199831de02e7d2f27f.1593318192.git.fthain@telegraphics.com.au

drivers/macintosh/via-macii.c

@@ -463,6 +463,21 @@ static irqreturn_t macii_interrupt(int irq, void *arg)
 
 				via[ACR] &= ~SR_OUT;
 				x = via[SR];
+			} else if ((req->data[1] & OP_MASK) == TALK) {
+				macii_state = reading;
+
+				reading_reply = 0;
+				reply_ptr = reply_buf;
+				*reply_ptr = req->data[1];
+				reply_len = 1;
+
+				via[ACR] &= ~SR_OUT;
+				x = via[SR];
+
+				req->complete = 1;
+				current_req = req->next;
+				if (req->done)
+					(*req->done)(req);
 			} else {
 				macii_state = idle;
 
@@ -510,8 +525,9 @@ static irqreturn_t macii_interrupt(int irq, void *arg)
 					current_req = req->next;
 					if (req->done)
 						(*req->done)(req);
-				} else if (reply_len && autopoll_devs) {
-					adb_input(reply_buf, reply_len, 0);
+				} else if (reply_len && autopoll_devs &&
+					   reply_buf[0] == last_poll_cmd) {
+					adb_input(reply_buf, reply_len, 1);
 				}
 				break;
 			}