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 "libc.h"
  12 #include "s390-ccw.h"
  13 #include "virtio.h"
  14
  15 char stack[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
  16 static SubChannelId blk_schid = { .one = 1 };
  17 IplParameterBlock iplb __attribute__((__aligned__(PAGE_SIZE)));
  18 static char loadparm[8] = { 0, 0, 0, 0, 0, 0, 0, 0 };
  19
  20 /*
  21  * Priniciples of Operations (SA22-7832-09) chapter 17 requires that
  22  * a subsystem-identification is at 184-187 and bytes 188-191 are zero
  23  * after list-directed-IPL and ccw-IPL.
  24  */
  25 void write_subsystem_identification(void)
  26 {
  27     SubChannelId *schid = (SubChannelId *) 184;
  28     uint32_t *zeroes = (uint32_t *) 188;
  29
  30     *schid = blk_schid;
  31     *zeroes = 0;
  32 }
  33
  34 void panic(const char *string)
  35 {
  36     sclp_print(string);
  37     disabled_wait();
  38     while (1) { }
  39 }
  40
  41 unsigned int get_loadparm_index(void)
  42 {
  43     const char *lp = loadparm;
  44     int i;
  45     unsigned int idx = 0;
  46
  47     for (i = 0; i < 8; i++) {
  48         char c = lp[i];
  49
  50         if (c < '0' || c > '9') {
  51             break;
  52         }
  53
  54         idx *= 10;
  55         idx += c - '0';
  56     }
  57
  58     return idx;
  59 }
  60
  61 static bool find_dev(Schib *schib, int dev_no)
  62 {
  63     int i, r;
  64
  65     for (i = 0; i < 0x10000; i++) {
  66         blk_schid.sch_no = i;
  67         r = stsch_err(blk_schid, schib);
  68         if ((r == 3) || (r == -EIO)) {
  69             break;
  70         }
  71         if (!schib->pmcw.dnv) {
  72             continue;
  73         }
  74         if (!virtio_is_supported(blk_schid)) {
  75             continue;
  76         }
  77         /* Skip net devices since no IPLB is created and therefore no
  78          * no network bootloader has been loaded
  79          */
  80         if (virtio_get_device_type() == VIRTIO_ID_NET && dev_no < 0) {
  81             continue;
  82         }
  83         if ((dev_no < 0) || (schib->pmcw.dev == dev_no)) {
  84             return true;
  85         }
  86     }
  87
  88     return false;
  89 }
  90
  91 static void virtio_setup(void)
  92 {
  93     Schib schib;
  94     int ssid;
  95     bool found = false;
  96     uint16_t dev_no;
  97     char ldp[] = "LOADPARM=[________]\n";
  98     VDev *vdev = virtio_get_device();
  99
 100     /*
 101      * We unconditionally enable mss support. In every sane configuration,
 102      * this will succeed; and even if it doesn't, stsch_err() can deal
 103      * with the consequences.
 104      */
 105     enable_mss_facility();
 106
 107     sclp_get_loadparm_ascii(loadparm);
 108     memcpy(ldp + 10, loadparm, 8);
 109     sclp_print(ldp);
 110
 111     if (store_iplb(&iplb)) {
 112         switch (iplb.pbt) {
 113         case S390_IPL_TYPE_CCW:
 114             dev_no = iplb.ccw.devno;
 115             debug_print_int("device no. ", dev_no);
 116             blk_schid.ssid = iplb.ccw.ssid & 0x3;
 117             debug_print_int("ssid ", blk_schid.ssid);
 118             found = find_dev(&schib, dev_no);
 119             break;
 120         case S390_IPL_TYPE_QEMU_SCSI:
 121             vdev->scsi_device_selected = true;
 122             vdev->selected_scsi_device.channel = iplb.scsi.channel;
 123             vdev->selected_scsi_device.target = iplb.scsi.target;
 124             vdev->selected_scsi_device.lun = iplb.scsi.lun;
 125             blk_schid.ssid = iplb.scsi.ssid & 0x3;
 126             found = find_dev(&schib, iplb.scsi.devno);
 127             break;
 128         default:
 129             panic("List-directed IPL not supported yet!\n");
 130         }
 131     } else {
 132         for (ssid = 0; ssid < 0x3; ssid++) {
 133             blk_schid.ssid = ssid;
 134             found = find_dev(&schib, -1);
 135             if (found) {
 136                 break;
 137             }
 138         }
 139     }
 140
 141     IPL_assert(found, "No virtio device found");
 142
 143     if (virtio_get_device_type() == VIRTIO_ID_NET) {
 144         sclp_print("Network boot device detected\n");
 145         vdev->netboot_start_addr = iplb.ccw.netboot_start_addr;
 146     } else {
 147         virtio_blk_setup_device(blk_schid);
 148
 149         IPL_assert(virtio_ipl_disk_is_valid(), "No valid IPL device detected");
 150     }
 151 }
 152
 153 int main(void)
 154 {
 155     sclp_setup();
 156     virtio_setup();
 157
 158     zipl_load(); /* no return */
 159
 160     panic("Failed to load OS from hard disk\n");
 161     return 0; /* make compiler happy */
 162 }