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