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