1 files changed, 116 insertions, 0 deletions
diff --git a/src/pc-bios/s390-ccw/main.c b/src/pc-bios/s390-ccw/main.c
new file mode 100644
index 0000000..d5fe4ce
--- /dev/null
+++ b/src/pc-bios/s390-ccw/main.c
@@ -0,0 +1,116 @@
+/*
+ * 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"
+#include "virtio.h"
+
+char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
+char ring_area[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
+uint64_t boot_value;
+static struct subchannel_id blk_schid = { .one = 1 };
+
+/*
+ * Priniciples of Operations (SA22-7832-09) chapter 17 requires that
+ * a subsystem-identification is at 184-187 and bytes 188-191 are zero
+ * after list-directed-IPL and ccw-IPL.
+ */
+void write_subsystem_identification(void)
+{
+    struct subchannel_id *schid = (struct subchannel_id *) 184;
+    uint32_t *zeroes = (uint32_t *) 188;
+
+    *schid = blk_schid;
+    *zeroes = 0;
+}
+
+
+void virtio_panic(const char *string)
+{
+    sclp_print(string);
+    disabled_wait();
+    while (1) { }
+}
+
+static bool find_dev(struct schib *schib, int dev_no)
+{
+    int i, r;
+
+    for (i = 0; i < 0x10000; i++) {
+        blk_schid.sch_no = i;
+        r = stsch_err(blk_schid, schib);
+        if ((r == 3) || (r == -EIO)) {
+            break;
+        }
+        if (!schib->pmcw.dnv) {
+            continue;
+        }
+        if (!virtio_is_blk(blk_schid)) {
+            continue;
+        }
+        if ((dev_no < 0) || (schib->pmcw.dev == dev_no)) {
+            return true;
+        }
+    }
+
+    return false;
+}
+
+static void virtio_setup(uint64_t dev_info)
+{
+    struct schib schib;
+    int ssid;
+    bool found = false;
+    uint16_t dev_no;
+
+    /*
+     * We unconditionally enable mss support. In every sane configuration,
+     * this will succeed; and even if it doesn't, stsch_err() can deal
+     * with the consequences.
+     */
+    enable_mss_facility();
+
+    if (dev_info != -1) {
+        dev_no = dev_info & 0xffff;
+        debug_print_int("device no. ", dev_no);
+        blk_schid.ssid = (dev_info >> 16) & 0x3;
+        debug_print_int("ssid ", blk_schid.ssid);
+        found = find_dev(&schib, dev_no);
+    } else {
+        for (ssid = 0; ssid < 0x3; ssid++) {
+            blk_schid.ssid = ssid;
+            found = find_dev(&schib, -1);
+            if (found) {
+                break;
+            }
+        }
+    }
+
+    if (!found) {
+        virtio_panic("No virtio-blk device found!\n");
+    }
+
+    virtio_setup_block(blk_schid);
+
+    if (!virtio_ipl_disk_is_valid()) {
+        virtio_panic("No valid hard disk detected.\n");
+    }
+}
+
+int main(void)
+{
+    sclp_setup();
+    debug_print_int("boot reg[7] ", boot_value);
+    virtio_setup(boot_value);
+
+    zipl_load(); /* no return */
+
+    virtio_panic("Failed to load OS from hard disk\n");
+    return 0; /* make compiler happy */
+}