S390: ccw firmware: Add main program

This C file is the main driving piece of the s390 ccw firmware. It
provides a search for a workable block device, sets it as the default
to boot off of and boots from it.

Signed-off-by: Alexander Graf <agraf@suse.de>

pc-bios/s390-ccw/main.c

@@ -0,0 +1,56 @@
+/*
+ * S390 virtio-ccw loading program
+ *
+ * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+
+#include "s390-ccw.h"
+
+struct subchannel_id blk_schid;
+char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
+
+void virtio_panic(const char *string)
+{
+    sclp_print(string);
+    while (1) { }
+}
+
+static void virtio_setup(void)
+{
+    struct irb irb;
+    int i;
+    int r;
+    bool found = false;
+
+    blk_schid.one = 1;
+
+    for (i = 0; i < 0x10000; i++) {
+        blk_schid.sch_no = i;
+        r = tsch(blk_schid, &irb);
+        if (r != 3) {
+            if (virtio_is_blk(blk_schid)) {
+                found = true;
+                break;
+            }
+        }
+    }
+
+    if (!found) {
+        virtio_panic("No virtio-blk device found!\n");
+    }
+
+    virtio_setup_block(blk_schid);
+}
+
+int main(void)
+{
+    sclp_setup();
+    virtio_setup();
+    if (zipl_load() < 0)
+        sclp_print("Failed to load OS from hard disk\n");
+    while (1) { }
+}