pcmcia: avoid late calls to pccard_validate_cis

pccard_validate_cis() nowadays destroys the CIS cache. Therefore,
calling it after card setup should be avoided. We can't control
the deprecated PCMCIA ioctl (which is only used on ARM nowadays),
but we can avoid -- and report -- any other calls.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
diff --git a/drivers/pcmcia/cistpl.c b/drivers/pcmcia/cistpl.c
index f230f65..854959c 100644
--- a/drivers/pcmcia/cistpl.c
+++ b/drivers/pcmcia/cistpl.c
@@ -1484,6 +1484,11 @@
 	if (!s)
 		return -EINVAL;
 
+	if (s->functions) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+
 	/* We do not want to validate the CIS cache... */
 	mutex_lock(&s->ops_mutex);
 	destroy_cis_cache(s);
@@ -1639,7 +1644,7 @@
 		count = 0;
 	else {
 		struct pcmcia_socket *s;
-		unsigned int chains;
+		unsigned int chains = 1;
 
 		if (off + count > size)
 			count = size - off;
@@ -1648,7 +1653,7 @@
 
 		if (!(s->state & SOCKET_PRESENT))
 			return -ENODEV;
-		if (pccard_validate_cis(s, &chains))
+		if (!s->functions && pccard_validate_cis(s, &chains))
 			return -EIO;
 		if (!chains)
 			return -ENODATA;