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 char ring_area[PAGE_SIZE * 8] __attribute__((__aligned__(PAGE_SIZE)));
  16 uint64_t boot_value;
  17 static struct subchannel_id blk_schid = { .one = 1 };
  18
  19 /*
  20  * Priniciples of Operations (SA22-7832-09) chapter 17 requires that
  21  * a subsystem-identification is at 184-187 and bytes 188-191 are zero
  22  * after list-directed-IPL and ccw-IPL.
  23  */
  24 void write_subsystem_identification(void)
  25 {
  26     struct subchannel_id *schid = (struct subchannel_id *) 184;
  27     uint32_t *zeroes = (uint32_t *) 188;
  28
  29     *schid = blk_schid;
  30     *zeroes = 0;
  31 }
  32
  33
  34 void virtio_panic(const char *string)
  35 {
  36     sclp_print(string);
  37     disabled_wait();
  38     while (1) { }
  39 }
  40
  41 static void virtio_setup(uint64_t dev_info)
  42 {
  43     struct schib schib;
  44     int i;
  45     int r;
  46     bool found = false;
  47     bool check_devno = false;
  48     uint16_t dev_no = -1;
  49
  50     if (dev_info != -1) {
  51         check_devno = true;
  52         dev_no = dev_info & 0xffff;
  53         debug_print_int("device no. ", dev_no);
  54         blk_schid.ssid = (dev_info >> 16) & 0x3;
  55         if (blk_schid.ssid != 0) {
  56             debug_print_int("ssid ", blk_schid.ssid);
  57             if (enable_mss_facility() != 0) {
  58                 virtio_panic("Failed to enable mss facility\n");
  59             }
  60         }
  61     }
  62
  63     for (i = 0; i < 0x10000; i++) {
  64         blk_schid.sch_no = i;
  65         r = stsch_err(blk_schid, &schib);
  66         if (r == 3) {
  67             break;
  68         }
  69         if (schib.pmcw.dnv) {
  70             if (!check_devno || (schib.pmcw.dev == dev_no)) {
  71                 if (virtio_is_blk(blk_schid)) {
  72                     found = true;
  73                     break;
  74                 }
  75             }
  76         }
  77     }
  78
  79     if (!found) {
  80         virtio_panic("No virtio-blk device found!\n");
  81     }
  82
  83     virtio_setup_block(blk_schid);
  84
  85     if (!virtio_ipl_disk_is_valid()) {
  86         virtio_panic("No valid hard disk detected.\n");
  87     }
  88 }
  89
  90 int main(void)
  91 {
  92     sclp_setup();
  93     debug_print_int("boot reg[7] ", boot_value);
  94     virtio_setup(boot_value);
  95
  96     zipl_load(); /* no return */
  97
  98     virtio_panic("Failed to load OS from hard disk\n");
  99     return 0; /* make compiler happy */
 100 }