Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 1 | /* |
| 2 | * This file is part of the coreboot project. |
| 3 | * |
| 4 | * Copyright (C) 2008 Rudolf Marek <r.marek@assembler.cz> |
| 5 | * Copyright (C) 2009 One Laptop per Child, Association, Inc. |
| 6 | * |
| 7 | * This program is free software; you can redistribute it and/or modify |
| 8 | * it under the terms of the GNU General Public License as published by |
| 9 | * the Free Software Foundation; either version 2 of the License, or |
| 10 | * (at your option) any later version. |
| 11 | * |
| 12 | * This program is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 15 | * GNU General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU General Public License |
| 18 | * along with this program; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 22 | /* reboot.c from Linux. */ |
| 23 | |
| 24 | /* |
| 25 | * This file mostly copied from Rudolf's S3 patch, some changes in |
| 26 | * acpi_jump_wake(). |
| 27 | */ |
| 28 | |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 29 | #include <stdint.h> |
| 30 | #include <string.h> |
| 31 | #include <arch/io.h> |
| 32 | #include <console/console.h> |
| 33 | #include <delay.h> |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 34 | #include <part/init_timer.h> /* for jason_tsc_count_end */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 35 | #include "wakeup.h" |
| 36 | |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 37 | int enable_a20(void); |
| 38 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 39 | /* |
| 40 | * The following code and data reboots the machine by switching to real |
| 41 | * mode and jumping to the BIOS reset entry point, as if the CPU has |
| 42 | * really been reset. The previous version asked the keyboard |
| 43 | * controller to pulse the CPU reset line, which is more thorough, but |
| 44 | * doesn't work with at least one type of 486 motherboard. It is easy |
| 45 | * to stop this code working; hence the copious comments. |
| 46 | */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 47 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 48 | static unsigned long long real_mode_gdt_entries[3] = { |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 49 | 0x0000000000000000ULL, /* Null descriptor */ |
| 50 | 0x00009a000000ffffULL, /* 16-bit real-mode 64k code at 0x00000000 */ |
| 51 | 0x000092000100ffffULL /* 16-bit real-mode 64k data at 0x00000100 */ |
| 52 | }; |
| 53 | |
| 54 | struct Xgt_desc_struct { |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 55 | unsigned short size; |
| 56 | unsigned long address __attribute__ ((packed)); |
| 57 | unsigned short pad; |
| 58 | } __attribute__ ((packed)); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 59 | |
| 60 | static struct Xgt_desc_struct |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 61 | real_mode_gdt = |
| 62 | { sizeof(real_mode_gdt_entries) - 1, (long)real_mode_gdt_entries }, |
| 63 | real_mode_idt = { |
| 64 | 0x3ff, 0}, no_idt = { |
| 65 | 0, 0}; |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 66 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 67 | /* |
| 68 | * This is 16-bit protected mode code to disable paging and the cache, |
| 69 | * switch to real mode and jump to the BIOS reset code. |
| 70 | * |
| 71 | * The instruction that switches to real mode by writing to CR0 must be |
| 72 | * followed immediately by a far jump instruction, which set CS to a |
| 73 | * valid value for real mode, and flushes the prefetch queue to avoid |
| 74 | * running instructions that have already been decoded in protected |
| 75 | * mode. |
| 76 | * |
| 77 | * Clears all the flags except ET, especially PG (paging), PE |
| 78 | * (protected-mode enable) and TS (task switch for coprocessor state |
| 79 | * save). Flushes the TLB after paging has been disabled. Sets CD and |
| 80 | * NW, to disable the cache on a 486, and invalidates the cache. This |
| 81 | * is more like the state of a 486 after reset. I don't know if |
| 82 | * something else should be done for other chips. |
| 83 | * |
| 84 | * More could be done here to set up the registers as if a CPU reset had |
| 85 | * occurred; hopefully real BIOSs don't assume much. |
| 86 | */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 87 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 88 | // 0x66, 0x0d, 0x00, 0x00, 0x00, 0x60, /* orl $0x60000000,%eax */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 89 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 90 | static unsigned char real_mode_switch[] = { |
| 91 | 0x66, 0x0f, 0x20, 0xc0, /* movl %cr0,%eax */ |
| 92 | 0x24, 0xfe, /* andb $0xfe,al */ |
| 93 | 0x66, 0x0f, 0x22, 0xc0 /* movl %eax,%cr0 */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 94 | }; |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 95 | |
| 96 | static unsigned char jump_to_wakeup[] = { |
| 97 | 0xea, 0x00, 0x00, 0x00, 0xe0 /* ljmp $0xffff, $0x0000 */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 98 | }; |
| 99 | |
| 100 | /* |
| 101 | * Switch to real mode and then execute the code |
| 102 | * specified by the code and length parameters. |
| 103 | * We assume that length will aways be less that 100! |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 104 | */ |
| 105 | static unsigned char show31[6] = { |
| 106 | 0xb0, 0x31, 0xe6, 0x80, 0xeb, 0xFA /* ljmp $0xffff,$0x0000 */ |
| 107 | }; |
| 108 | |
| 109 | static unsigned char show32[6] = { |
| 110 | 0xb0, 0x32, 0xe6, 0x80, 0xeb, 0xFA /* ljmp $0xffff,$0x0000 */ |
| 111 | }; |
| 112 | |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 113 | void acpi_jump_wake(u32 vector) |
| 114 | { |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 115 | u32 tmp; |
| 116 | u16 tmpvector; |
| 117 | u32 dwEip; |
| 118 | u8 Data; |
| 119 | struct Xgt_desc_struct *wake_thunk16_Xgt_desc; |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 120 | |
| 121 | printk_debug("IN ACPI JUMP WAKE TO %x\n", vector); |
| 122 | if (enable_a20()) |
| 123 | die("failed to enable A20\n"); |
| 124 | printk_debug("IN ACPI JUMP WAKE TO 3 %x\n", vector); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 125 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 126 | *((u16 *) (jump_to_wakeup + 3)) = (u16) (vector >> 4); |
| 127 | printk_debug("%x %x %x %x %x\n", jump_to_wakeup[0], jump_to_wakeup[1], |
| 128 | jump_to_wakeup[2], jump_to_wakeup[3], jump_to_wakeup[4]); |
| 129 | |
| 130 | memcpy((void *)(WAKE_THUNK16_ADDR - sizeof(real_mode_switch) - 100), |
| 131 | real_mode_switch, sizeof(real_mode_switch)); |
| 132 | memcpy((void *)(WAKE_THUNK16_ADDR - 100), jump_to_wakeup, |
| 133 | sizeof(jump_to_wakeup)); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 134 | |
| 135 | jason_tsc_count(); |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 136 | printk_emerg("file '%s', line %d\n\n", __FILE__, __LINE__); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 137 | jason_tsc_count_end(); |
| 138 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 139 | unsigned long long *real_mode_gdt_entries_at_eseg; |
| 140 | real_mode_gdt_entries_at_eseg = WAKE_THUNK16_GDT; //copy from real_mode_gdt_entries and change limition to 1M and data base to 0; |
| 141 | real_mode_gdt_entries_at_eseg[0] = 0x0000000000000000ULL; /* Null descriptor */ |
| 142 | real_mode_gdt_entries_at_eseg[1] = 0x000f9a000000ffffULL; /* 16-bit real-mode 1M code at 0x00000000 */ |
| 143 | real_mode_gdt_entries_at_eseg[2] = 0x000f93000000ffffULL; /* 16-bit real-mode 1M data at 0x00000000 */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 144 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 145 | wake_thunk16_Xgt_desc = WAKE_THUNK16_XDTR; |
| 146 | wake_thunk16_Xgt_desc[0].size = sizeof(real_mode_gdt_entries) - 1; |
| 147 | wake_thunk16_Xgt_desc[0].address = (long)real_mode_gdt_entries_at_eseg; |
| 148 | wake_thunk16_Xgt_desc[1].size = 0x3ff; |
| 149 | wake_thunk16_Xgt_desc[1].address = 0; |
| 150 | wake_thunk16_Xgt_desc[2].size = 0; |
| 151 | wake_thunk16_Xgt_desc[2].address = 0; |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 152 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 153 | /*added this code to get current value of EIP |
| 154 | */ |
| 155 | __asm__ volatile ("calll geip\n\t" |
| 156 | "geip: \n\t" "popl %0\n\t":"=a" (dwEip) |
| 157 | ); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 158 | |
| 159 | unsigned char *dest; |
| 160 | unsigned char *src; |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 161 | src = (unsigned char *)dwEip; |
| 162 | dest = WAKE_RECOVER1M_CODE; |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 163 | u32 i; |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 164 | for (i = 0; i < 0x200; i++) |
| 165 | dest[i] = src[i]; |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 166 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 167 | __asm__ __volatile__("ljmp $0x0010,%0" //08 error |
| 168 | ::"i"((void *)(WAKE_RECOVER1M_CODE + 0x20))); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 169 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 170 | /*added 0x20 "nop" to make sure the ljmp will not jump then halt */ |
| 171 | asm volatile ("nop"); |
| 172 | asm volatile ("nop"); |
| 173 | asm volatile ("nop"); |
| 174 | asm volatile ("nop"); |
| 175 | asm volatile ("nop"); |
| 176 | asm volatile ("nop"); |
| 177 | asm volatile ("nop"); |
| 178 | asm volatile ("nop"); |
| 179 | asm volatile ("nop"); |
| 180 | asm volatile ("nop"); |
| 181 | |
| 182 | asm volatile ("nop"); |
| 183 | asm volatile ("nop"); |
| 184 | asm volatile ("nop"); |
| 185 | asm volatile ("nop"); |
| 186 | asm volatile ("nop"); |
| 187 | asm volatile ("nop"); |
| 188 | asm volatile ("nop"); |
| 189 | asm volatile ("nop"); |
| 190 | asm volatile ("nop"); |
| 191 | asm volatile ("nop"); |
| 192 | |
| 193 | asm volatile ("nop"); |
| 194 | asm volatile ("nop"); |
| 195 | asm volatile ("nop"); |
| 196 | asm volatile ("nop"); |
| 197 | asm volatile ("nop"); |
| 198 | asm volatile ("nop"); |
| 199 | asm volatile ("nop"); |
| 200 | asm volatile ("nop"); |
| 201 | asm volatile ("nop"); |
| 202 | asm volatile ("nop"); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 203 | |
| 204 | __asm__ volatile ( |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 205 | /* set new esp, maybe ebp should not equal to esp?, |
| 206 | due to the variable in acpi_jump_wake?, anyway, this may be not a big problem. |
| 207 | and I didnt clear the area (ef000+-0x200) to zero. |
| 208 | */ |
| 209 | "movl %0, %%ebp\n\t" |
| 210 | "movl %0, %%esp\n\t"::"a" (WAKE_THUNK16_STACK) |
| 211 | ); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 212 | |
| 213 | /* added this |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 214 | only "src" and "dest" use the new stack, and the esp maybe also used in resumevector |
| 215 | */ |
| 216 | #if PAYLOAD_IS_SEABIOS==1 |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 217 | // WAKE_MEM_INFO inited in get_set_top_available_mem in tables.c |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 218 | src = |
| 219 | (unsigned char *)((*(u32 *) WAKE_MEM_INFO) - 64 * 1024 - 0x100000); |
| 220 | dest = 0; |
| 221 | for (i = 0; i < 0xa0000; i++) //if recovered 0-e0000, then when resume, before winxp turn on the desktop screen ,there is gray background which last 1sec. |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 222 | dest[i] = src[i]; |
| 223 | /*__asm__ volatile ( |
| 224 | "movl %0, %%esi\n\t" |
| 225 | "movl $0, %%edi\n\t" |
| 226 | "movl $0xa0000, %%ecx\n\t" |
| 227 | "shrl $2, %%ecx\n\t" |
| 228 | "rep movsd\n\t" |
| 229 | ::"a"(src) |
| 230 | );*/ |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 231 | src = |
| 232 | (unsigned char *)((*(u32 *) WAKE_MEM_INFO) - 64 * 1024 - 0x100000 + |
| 233 | 0xc0000); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 234 | //dest = 0xc0000; |
| 235 | //for (i = 0; i < 0x20000; i++) |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 236 | // dest[i] = src[i]; |
| 237 | /* __asm__ volatile ( |
| 238 | "movl %0, %%esi\n\t" |
| 239 | "movl $0xc0000, %%edi\n\t" |
| 240 | "movl $0x20000, %%ecx\n\t" |
| 241 | "shrl $2, %%ecx\n\t" |
| 242 | "rep movsd\n\t" |
| 243 | ::"a"(src) |
| 244 | ); */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 245 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 246 | src = |
| 247 | (unsigned char *)((*(u32 *) WAKE_MEM_INFO) - 64 * 1024 - 0x100000 + |
| 248 | 0xe0000 + WAKE_SPECIAL_SIZE); |
| 249 | //dest = 0xf0000; |
| 250 | //for (i = 0; i < 0x10000; i++) |
| 251 | // dest[i] = src[i]; |
| 252 | __asm__ volatile ("movl %0, %%esi\n\t" |
| 253 | "movl %1, %%edi\n\t" |
| 254 | "movl %2, %%ecx\n\t" |
| 255 | "shrl $2, %%ecx\n\t" |
| 256 | "rep movsd\n\t"::"r" (src), |
| 257 | "r"(0xe0000 + WAKE_SPECIAL_SIZE), |
| 258 | "r"(0x10000 - WAKE_SPECIAL_SIZE) |
| 259 | ); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 260 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 261 | src = |
| 262 | (unsigned char *)((*(u32 *) WAKE_MEM_INFO) - 64 * 1024 - 0x100000 + |
| 263 | 0xf0000); |
| 264 | //dest = 0xf0000; |
| 265 | //for (i = 0; i < 0x10000; i++) |
| 266 | // dest[i] = src[i]; |
| 267 | __asm__ volatile ("movl %0, %%esi\n\t" |
| 268 | "movl $0xf0000, %%edi\n\t" |
| 269 | "movl $0x10000, %%ecx\n\t" |
| 270 | "shrl $2, %%ecx\n\t" "rep movsd\n\t"::"a" (src) |
| 271 | ); |
| 272 | |
| 273 | asm volatile ("wbinvd"); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 274 | #endif |
| 275 | /* Set up the IDT for real mode. */ |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 276 | asm volatile ("lidt %0"::"m" (wake_thunk16_Xgt_desc[1])); |
| 277 | |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 278 | /* Set up a GDT from which we can load segment descriptors for real |
| 279 | mode. The GDT is not used in real mode; it is just needed here to |
| 280 | prepare the descriptors. */ |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 281 | asm volatile ("lgdt %0"::"m" (wake_thunk16_Xgt_desc[0])); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 282 | |
| 283 | /* Load the data segment registers, and thus the descriptors ready for |
| 284 | real mode. The base address of each segment is 0x100, 16 times the |
| 285 | selector value being loaded here. This is so that the segment |
| 286 | registers don't have to be reloaded after switching to real mode: |
| 287 | the values are consistent for real mode operation already. */ |
| 288 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 289 | __asm__ __volatile__("movl $0x0010,%%eax\n" |
| 290 | "\tmovl %%eax,%%ds\n" |
| 291 | "\tmovl %%eax,%%es\n" |
| 292 | "\tmovl %%eax,%%fs\n" |
| 293 | "\tmovl %%eax,%%gs\n" "\tmovl %%eax,%%ss":::"eax"); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 294 | |
| 295 | /* Jump to the 16-bit code that we copied earlier. It disables paging |
| 296 | and the cache, switches to real mode, and jumps to the BIOS reset |
| 297 | entry point. */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 298 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 299 | __asm__ |
| 300 | __volatile__("ljmp $0x0008,%0"::"i" |
| 301 | ((void *)(WAKE_THUNK16_ADDR - |
| 302 | sizeof(real_mode_switch) - 100))); |
| 303 | } |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 304 | |
| 305 | /* -*- linux-c -*- ------------------------------------------------------- * |
| 306 | * |
| 307 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 308 | * Copyright 2007 rPath, Inc. - All Rights Reserved |
| 309 | * |
| 310 | * This file is part of the Linux kernel, and is made available under |
| 311 | * the terms of the GNU General Public License version 2. |
| 312 | * |
| 313 | * ----------------------------------------------------------------------- */ |
| 314 | |
| 315 | /* |
| 316 | * arch/i386/boot/a20.c |
| 317 | * |
| 318 | * Enable A20 gate (return -1 on failure) |
| 319 | */ |
| 320 | |
| 321 | //#include "boot.h" |
| 322 | |
| 323 | #define MAX_8042_LOOPS 100000 |
| 324 | |
| 325 | static int empty_8042(void) |
| 326 | { |
| 327 | u8 status; |
| 328 | int loops = MAX_8042_LOOPS; |
| 329 | |
| 330 | while (loops--) { |
| 331 | udelay(1); |
| 332 | |
| 333 | status = inb(0x64); |
| 334 | if (status & 1) { |
| 335 | /* Read and discard input data */ |
| 336 | udelay(1); |
| 337 | (void)inb(0x60); |
| 338 | } else if (!(status & 2)) { |
| 339 | /* Buffers empty, finished! */ |
| 340 | return 0; |
| 341 | } |
| 342 | } |
| 343 | |
| 344 | return -1; |
| 345 | } |
| 346 | |
| 347 | /* Returns nonzero if the A20 line is enabled. The memory address |
| 348 | used as a test is the int $0x80 vector, which should be safe. */ |
| 349 | |
| 350 | #define A20_TEST_ADDR (4*0x80) |
| 351 | #define A20_TEST_SHORT 32 |
| 352 | #define A20_TEST_LONG 2097152 /* 2^21 */ |
| 353 | |
| 354 | static int a20_test(int loops) |
| 355 | { |
| 356 | int ok = 0; |
| 357 | int saved, ctr; |
| 358 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 359 | // set_fs(0x0000); |
| 360 | // set_gs(0xffff); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 361 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 362 | saved = ctr = *((u32 *) A20_TEST_ADDR); |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 363 | |
| 364 | while (loops--) { |
| 365 | //wrfs32(++ctr, A20_TEST_ADDR); |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 366 | |
| 367 | *((u32 *) A20_TEST_ADDR) = ++ctr; |
| 368 | |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 369 | udelay(1); /* Serialize and make delay constant */ |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 370 | |
| 371 | ok = *((u32 *) A20_TEST_ADDR + 0xffff0 + 0x10) ^ ctr; |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 372 | if (ok) |
| 373 | break; |
| 374 | } |
| 375 | |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 376 | *((u32 *) A20_TEST_ADDR) = saved; |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 377 | return ok; |
| 378 | } |
| 379 | |
| 380 | /* Quick test to see if A20 is already enabled */ |
| 381 | static int a20_test_short(void) |
| 382 | { |
| 383 | return a20_test(A20_TEST_SHORT); |
| 384 | } |
| 385 | |
| 386 | /* Longer test that actually waits for A20 to come on line; this |
| 387 | is useful when dealing with the KBC or other slow external circuitry. */ |
| 388 | static int a20_test_long(void) |
| 389 | { |
| 390 | return a20_test(A20_TEST_LONG); |
| 391 | } |
| 392 | |
| 393 | static void enable_a20_kbc(void) |
| 394 | { |
| 395 | empty_8042(); |
| 396 | |
| 397 | outb(0xd1, 0x64); /* Command write */ |
| 398 | empty_8042(); |
| 399 | |
| 400 | outb(0xdf, 0x60); /* A20 on */ |
| 401 | empty_8042(); |
| 402 | } |
| 403 | |
| 404 | static void enable_a20_fast(void) |
| 405 | { |
| 406 | u8 port_a; |
| 407 | |
| 408 | port_a = inb(0x92); /* Configuration port A */ |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 409 | port_a |= 0x02; /* Enable A20 */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 410 | port_a &= ~0x01; /* Do not reset machine */ |
| 411 | outb(port_a, 0x92); |
| 412 | } |
| 413 | |
| 414 | /* |
| 415 | * Actual routine to enable A20; return 0 on ok, -1 on failure |
| 416 | */ |
| 417 | |
| 418 | #define A20_ENABLE_LOOPS 255 /* Number of times to try */ |
| 419 | |
| 420 | int enable_a20(void) |
| 421 | { |
| 422 | int loops = A20_ENABLE_LOOPS; |
| 423 | |
| 424 | while (loops--) { |
| 425 | /* First, check to see if A20 is already enabled |
| 426 | (legacy free, etc.) */ |
| 427 | if (a20_test_short()) |
| 428 | return 0; |
| 429 | |
| 430 | /* Try enabling A20 through the keyboard controller */ |
| 431 | empty_8042(); |
| 432 | //if (a20_test_short()) |
Uwe Hermann | 0ffff34 | 2009-06-07 13:46:50 +0000 | [diff] [blame^] | 433 | // return 0; /* BIOS worked, but with delayed reaction */ |
Uwe Hermann | 20a98c9 | 2009-06-05 23:02:43 +0000 | [diff] [blame] | 434 | |
| 435 | enable_a20_kbc(); |
| 436 | if (a20_test_long()) |
| 437 | return 0; |
| 438 | |
| 439 | /* Finally, try enabling the "fast A20 gate" */ |
| 440 | enable_a20_fast(); |
| 441 | if (a20_test_long()) |
| 442 | return 0; |
| 443 | } |
| 444 | |
| 445 | return -1; |
| 446 | } |