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 bool find_dev(struct schib *schib, int dev_no) 42 { 43 int i, r; 44 45 for (i = 0; i < 0x10000; i++) { 46 blk_schid.sch_no = i; 47 r = stsch_err(blk_schid, schib); 48 if ((r == 3) || (r == -EIO)) { 49 break; 50 } 51 if (!schib->pmcw.dnv) { 52 continue; 53 } 54 if (!virtio_is_blk(blk_schid)) { 55 continue; 56 } 57 if ((dev_no < 0) || (schib->pmcw.dev == dev_no)) { 58 return true; 59 } 60 } 61 62 return false; 63 } 64 65 static void virtio_setup(uint64_t dev_info) 66 { 67 struct schib schib; 68 int ssid; 69 bool found = false; 70 uint16_t dev_no; 71 72 /* 73 * We unconditionally enable mss support. In every sane configuration, 74 * this will succeed; and even if it doesn't, stsch_err() can deal 75 * with the consequences. 76 */ 77 enable_mss_facility(); 78 79 if (dev_info != -1) { 80 dev_no = dev_info & 0xffff; 81 debug_print_int("device no. ", dev_no); 82 blk_schid.ssid = (dev_info >> 16) & 0x3; 83 debug_print_int("ssid ", blk_schid.ssid); 84 found = find_dev(&schib, dev_no); 85 } else { 86 for (ssid = 0; ssid < 0x3; ssid++) { 87 blk_schid.ssid = ssid; 88 found = find_dev(&schib, -1); 89 if (found) { 90 break; 91 } 92 } 93 } 94 95 if (!found) { 96 virtio_panic("No virtio-blk device found!\n"); 97 } 98 99 virtio_setup_block(blk_schid); 100 101 if (!virtio_ipl_disk_is_valid()) { 102 virtio_panic("No valid hard disk detected.\n"); 103 } 104 } 105 106 int main(void) 107 { 108 sclp_setup(); 109 debug_print_int("boot reg[7] ", boot_value); 110 virtio_setup(boot_value); 111 112 zipl_load(); /* no return */ 113 114 virtio_panic("Failed to load OS from hard disk\n"); 115 return 0; /* make compiler happy */ 116 } 117