LXR qemu/pc-bios/s390-ccw/main.c

   1/*
   2 * S390 virtio-ccw loading program
   3 *
   4 * Copyright (c) 2013 Alexander Graf <agraf@suse.de>
   5 *
   6 * This work is licensed under the terms of the GNU GPL, version 2 or (at
   7 * your option) any later version. See the COPYING file in the top-level
   8 * directory.
   9 */
  10
  11#include "s390-ccw.h"
  12#include "virtio.h"
  13
  14char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
  15uint64_t boot_value;
  16static SubChannelId blk_schid = { .one = 1 };
  17
  18/*
  19 * Priniciples of Operations (SA22-7832-09) chapter 17 requires that
  20 * a subsystem-identification is at 184-187 and bytes 188-191 are zero
  21 * after list-directed-IPL and ccw-IPL.
  22 */
  23void write_subsystem_identification(void)
  24{
  25    SubChannelId *schid = (SubChannelId *) 184;
  26    uint32_t *zeroes = (uint32_t *) 188;
  27
  28    *schid = blk_schid;
  29    *zeroes = 0;
  30}
  31
  32
  33void panic(const char *string)
  34{
  35    sclp_print(string);
  36    disabled_wait();
  37    while (1) { }
  38}
  39
  40static bool find_dev(Schib *schib, int dev_no)
  41{
  42    int i, r;
  43
  44    for (i = 0; i < 0x10000; i++) {
  45        blk_schid.sch_no = i;
  46        r = stsch_err(blk_schid, schib);
  47        if ((r == 3) || (r == -EIO)) {
  48            break;
  49        }
  50        if (!schib->pmcw.dnv) {
  51            continue;
  52        }
  53        if (!virtio_is_supported(blk_schid)) {
  54            continue;
  55        }
  56        if ((dev_no < 0) || (schib->pmcw.dev == dev_no)) {
  57            return true;
  58        }
  59    }
  60
  61    return false;
  62}
  63
  64static void virtio_setup(uint64_t dev_info)
  65{
  66    Schib schib;
  67    int ssid;
  68    bool found = false;
  69    uint16_t dev_no;
  70
  71    /*
  72     * We unconditionally enable mss support. In every sane configuration,
  73     * this will succeed; and even if it doesn't, stsch_err() can deal
  74     * with the consequences.
  75     */
  76    enable_mss_facility();
  77
  78    if (dev_info != -1) {
  79        dev_no = dev_info & 0xffff;
  80        debug_print_int("device no. ", dev_no);
  81        blk_schid.ssid = (dev_info >> 16) & 0x3;
  82        debug_print_int("ssid ", blk_schid.ssid);
  83        found = find_dev(&schib, dev_no);
  84    } else {
  85        for (ssid = 0; ssid < 0x3; ssid++) {
  86            blk_schid.ssid = ssid;
  87            found = find_dev(&schib, -1);
  88            if (found) {
  89                break;
  90            }
  91        }
  92    }
  93
  94    IPL_assert(found, "No virtio device found");
  95
  96    virtio_setup_device(blk_schid);
  97
  98    IPL_assert(virtio_ipl_disk_is_valid(), "No valid IPL device detected");
  99}
 100
 101int main(void)
 102{
 103    sclp_setup();
 104    debug_print_int("boot reg[7] ", boot_value);
 105    virtio_setup(boot_value);
 106
 107    zipl_load(); /* no return */
 108
 109    panic("Failed to load OS from hard disk\n");
 110    return 0; /* make compiler happy */
 111}
 112