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
  14 char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
  15 static SubChannelId blk_schid = { .one = 1 };
  16 IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
  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  */
  23 void 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
  33 void panic(const char *string)
  34 {
  35     sclp_print(string);
  36     disabled_wait();
  37     while (1) { }
  38 }
  39
  40 static 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         /* Skip net devices since no IPLB is created and therefore no
  57          * no network bootloader has been loaded
  58          */
  59         if (virtio_get_device_type() == VIRTIO_ID_NET && dev_no < 0) {
  60             continue;
  61         }
  62         if ((dev_no < 0) || (schib->pmcw.dev == dev_no)) {
  63             return true;
  64         }
  65     }
  66
  67     return false;
  68 }
  69
  70 static void virtio_setup(void)
  71 {
  72     Schib schib;
  73     int ssid;
  74     bool found = false;
  75     uint16_t dev_no;
  76     VDev *vdev = virtio_get_device();
  77
  78     /*
  79      * We unconditionally enable mss support. In every sane configuration,
  80      * this will succeed; and even if it doesn't, stsch_err() can deal
  81      * with the consequences.
  82      */
  83     enable_mss_facility();
  84
  85     if (store_iplb(&iplb)) {
  86         switch (iplb.pbt) {
  87         case S390_IPL_TYPE_CCW:
  88             dev_no = iplb.ccw.devno;
  89             debug_print_int("device no. ", dev_no);
  90             blk_schid.ssid = iplb.ccw.ssid & 0x3;
  91             debug_print_int("ssid ", blk_schid.ssid);
  92             found = find_dev(&schib, dev_no);
  93             break;
  94         case S390_IPL_TYPE_QEMU_SCSI:
  95             vdev->scsi_device_selected = true;
  96             vdev->selected_scsi_device.channel = iplb.scsi.channel;
  97             vdev->selected_scsi_device.target = iplb.scsi.target;
  98             vdev->selected_scsi_device.lun = iplb.scsi.lun;
  99             blk_schid.ssid = iplb.scsi.ssid & 0x3;
 100             found = find_dev(&schib, iplb.scsi.devno);
 101             break;
 102         default:
 103             panic("List-directed IPL not supported yet!\n");
 104         }
 105     } else {
 106         for (ssid = 0; ssid < 0x3; ssid++) {
 107             blk_schid.ssid = ssid;
 108             found = find_dev(&schib, -1);
 109             if (found) {
 110                 break;
 111             }
 112         }
 113     }
 114
 115     IPL_assert(found, "No virtio device found");
 116
 117     if (virtio_get_device_type() == VIRTIO_ID_NET) {
 118         sclp_print("Network boot device detected\n");
 119         vdev->netboot_start_addr = iplb.ccw.netboot_start_addr;
 120     } else {
 121         virtio_setup_device(blk_schid);
 122
 123         IPL_assert(virtio_ipl_disk_is_valid(), "No valid IPL device detected");
 124     }
 125 }
 126
 127 int main(void)
 128 {
 129     sclp_setup();
 130     virtio_setup();
 131
 132     zipl_load(); /* no return */
 133
 134     panic("Failed to load OS from hard disk\n");
 135     return 0; /* make compiler happy */
 136 }