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1.1 root 1: // Support for booting from cdroms (the "El Torito" spec).
2: //
3: // Copyright (C) 2008,2009 Kevin O'Connor <[email protected]>
4: // Copyright (C) 2002 MandrakeSoft S.A.
5: //
6: // This file may be distributed under the terms of the GNU LGPLv3 license.
7:
8: #include "disk.h" // cdrom_13
9: #include "util.h" // memset
10: #include "bregs.h" // struct bregs
11: #include "biosvar.h" // GET_EBDA
12: #include "ata.h" // ATA_CMD_REQUEST_SENSE
13:
14:
15: /****************************************************************
16: * CD emulation
17: ****************************************************************/
18:
19: static int
20: cdemu_read(struct disk_op_s *op)
21: {
22: u16 ebda_seg = get_ebda_seg();
23: struct drive_s *drive_g = GET_EBDA2(ebda_seg, cdemu.emulated_drive);
24: struct disk_op_s dop;
25: dop.drive_g = drive_g;
26: dop.command = op->command;
27: dop.lba = GET_EBDA2(ebda_seg, cdemu.ilba) + op->lba / 4;
28:
29: int count = op->count;
30: op->count = 0;
31: u8 *cdbuf_far = (void*)offsetof(struct extended_bios_data_area_s, cdemu_buf);
32:
33: if (op->lba & 3) {
34: // Partial read of first block.
35: dop.count = 1;
36: dop.buf_fl = MAKE_FLATPTR(ebda_seg, cdbuf_far);
37: int ret = process_op(&dop);
38: if (ret)
39: return ret;
40: u8 thiscount = 4 - (op->lba & 3);
41: if (thiscount > count)
42: thiscount = count;
43: count -= thiscount;
44: memcpy_far(FLATPTR_TO_SEG(op->buf_fl)
45: , (void*)FLATPTR_TO_OFFSET(op->buf_fl)
46: , ebda_seg, cdbuf_far + (op->lba & 3) * 512
47: , thiscount * 512);
48: op->buf_fl += thiscount * 512;
49: op->count += thiscount;
50: dop.lba++;
51: }
52:
53: if (count > 3) {
54: // Read n number of regular blocks.
55: dop.count = count / 4;
56: dop.buf_fl = op->buf_fl;
57: int ret = process_op(&dop);
58: op->count += dop.count * 4;
59: if (ret)
60: return ret;
61: u8 thiscount = count & ~3;
62: count &= 3;
63: op->buf_fl += thiscount * 512;
64: dop.lba += thiscount / 4;
65: }
66:
67: if (count) {
68: // Partial read on last block.
69: dop.count = 1;
70: dop.buf_fl = MAKE_FLATPTR(ebda_seg, cdbuf_far);
71: int ret = process_op(&dop);
72: if (ret)
73: return ret;
74: u8 thiscount = count;
75: memcpy_far(FLATPTR_TO_SEG(op->buf_fl)
76: , (void*)FLATPTR_TO_OFFSET(op->buf_fl)
77: , ebda_seg, cdbuf_far, thiscount * 512);
78: op->count += thiscount;
79: }
80:
81: return DISK_RET_SUCCESS;
82: }
83:
84: int
85: process_cdemu_op(struct disk_op_s *op)
86: {
87: if (!CONFIG_CDROM_EMU)
88: return 0;
89:
90: switch (op->command) {
91: case CMD_READ:
92: return cdemu_read(op);
93: case CMD_WRITE:
94: case CMD_FORMAT:
95: return DISK_RET_EWRITEPROTECT;
96: case CMD_VERIFY:
97: case CMD_RESET:
98: case CMD_SEEK:
99: case CMD_ISREADY:
100: return DISK_RET_SUCCESS;
101: default:
102: op->count = 0;
103: return DISK_RET_EPARAM;
104: }
105: }
106:
107: struct drive_s *cdemu_drive VAR16VISIBLE;
108:
109: void
110: cdemu_setup()
111: {
112: if (!CONFIG_CDROM_EMU)
113: return;
114:
115: struct drive_s *drive_g = allocDrive();
116: if (!drive_g) {
117: cdemu_drive = NULL;
118: return;
119: }
120: cdemu_drive = ADJUST_GLOBAL_PTR(drive_g);
121: drive_g->type = DTYPE_CDEMU;
122: drive_g->blksize = DISK_SECTOR_SIZE;
123: drive_g->sectors = (u64)-1;
124: }
125:
126: struct eltorito_s {
127: u8 size;
128: u8 media;
129: u8 emulated_drive;
130: u8 controller_index;
131: u32 ilba;
132: u16 device_spec;
133: u16 buffer_segment;
134: u16 load_segment;
135: u16 sector_count;
136: u8 cylinders;
137: u8 sectors;
138: u8 heads;
139: };
140:
141: #define SET_INT13ET(regs,var,val) \
142: SET_FARVAR((regs)->ds, ((struct eltorito_s*)((regs)->si+0))->var, (val))
143:
144: // ElTorito - Terminate disk emu
145: void
146: cdemu_134b(struct bregs *regs)
147: {
148: // FIXME ElTorito Hardcoded
149: u16 ebda_seg = get_ebda_seg();
150: SET_INT13ET(regs, size, 0x13);
151: SET_INT13ET(regs, media, GET_EBDA2(ebda_seg, cdemu.media));
152: SET_INT13ET(regs, emulated_drive
153: , GET_EBDA2(ebda_seg, cdemu.emulated_extdrive));
154: struct drive_s *drive_g = GET_EBDA2(ebda_seg, cdemu.emulated_drive);
155: u8 cntl_id = GET_GLOBAL(drive_g->cntl_id);
156: SET_INT13ET(regs, controller_index, cntl_id / 2);
157: SET_INT13ET(regs, device_spec, cntl_id % 2);
158: SET_INT13ET(regs, ilba, GET_EBDA2(ebda_seg, cdemu.ilba));
159: SET_INT13ET(regs, buffer_segment, GET_EBDA2(ebda_seg, cdemu.buffer_segment));
160: SET_INT13ET(regs, load_segment, GET_EBDA2(ebda_seg, cdemu.load_segment));
161: SET_INT13ET(regs, sector_count, GET_EBDA2(ebda_seg, cdemu.sector_count));
162: SET_INT13ET(regs, cylinders, GET_EBDA2(ebda_seg, cdemu.lchs.cylinders));
163: SET_INT13ET(regs, sectors, GET_EBDA2(ebda_seg, cdemu.lchs.spt));
164: SET_INT13ET(regs, heads, GET_EBDA2(ebda_seg, cdemu.lchs.heads));
165:
166: // If we have to terminate emulation
167: if (regs->al == 0x00) {
168: // FIXME ElTorito Various. Should be handled accordingly to spec
169: SET_EBDA2(ebda_seg, cdemu.active, 0x00); // bye bye
170: }
171:
172: disk_ret(regs, DISK_RET_SUCCESS);
173: }
174:
175:
176: /****************************************************************
177: * CD booting
178: ****************************************************************/
179:
180: // Request SENSE
181: static int
182: atapi_get_sense(struct drive_s *drive_g, u8 *asc, u8 *ascq)
183: {
184: u8 atacmd[12], buffer[18];
185: memset(atacmd, 0, sizeof(atacmd));
186: atacmd[0] = ATA_CMD_REQUEST_SENSE;
187: atacmd[4] = sizeof(buffer);
188: int ret = ata_cmd_packet(drive_g, atacmd, sizeof(atacmd), sizeof(buffer)
189: , MAKE_FLATPTR(GET_SEG(SS), buffer));
190: if (ret)
191: return ret;
192:
193: *asc = buffer[12];
194: *ascq = buffer[13];
195:
196: return 0;
197: }
198:
199: // Request capacity
200: static int
201: atapi_read_capacity(struct drive_s *drive_g, u32 *blksize, u32 *sectors)
202: {
203: u8 packet[12], buf[8];
204: memset(packet, 0, sizeof(packet));
205: packet[0] = 0x25; /* READ CAPACITY */
206: int ret = ata_cmd_packet(drive_g, packet, sizeof(packet), sizeof(buf)
207: , MAKE_FLATPTR(GET_SEG(SS), buf));
208: if (ret)
209: return ret;
210:
211: *blksize = (((u32)buf[4] << 24) | ((u32)buf[5] << 16)
212: | ((u32)buf[6] << 8) | ((u32)buf[7] << 0));
213: *sectors = (((u32)buf[0] << 24) | ((u32)buf[1] << 16)
214: | ((u32)buf[2] << 8) | ((u32)buf[3] << 0));
215:
216: return 0;
217: }
218:
219: static int
220: atapi_is_ready(struct drive_s *drive_g)
221: {
222: dprintf(6, "atapi_is_ready (drive=%p)\n", drive_g);
223:
224: /* Retry READ CAPACITY for 5 seconds unless MEDIUM NOT PRESENT is
225: * reported by the device. If the device reports "IN PROGRESS",
226: * 30 seconds is added. */
227: u32 blksize, sectors;
228: int in_progress = 0;
229: u64 end = calc_future_tsc(5000);
230: for (;;) {
231: if (check_time(end)) {
232: dprintf(1, "read capacity failed\n");
233: return -1;
234: }
235:
236: int ret = atapi_read_capacity(drive_g, &blksize, §ors);
237: if (!ret)
238: // Success
239: break;
240:
241: u8 asc, ascq;
242: ret = atapi_get_sense(drive_g, &asc, &ascq);
243: if (ret)
244: // Error - retry.
245: continue;
246:
247: // Sense succeeded.
248: if (asc == 0x3a) { /* MEDIUM NOT PRESENT */
249: dprintf(1, "Device reports MEDIUM NOT PRESENT\n");
250: return -1;
251: }
252:
253: if (asc == 0x04 && ascq == 0x01 && !in_progress) {
254: /* IN PROGRESS OF BECOMING READY */
255: printf("Waiting for device to detect medium... ");
256: /* Allow 30 seconds more */
257: end = calc_future_tsc(30000);
258: in_progress = 1;
259: }
260: }
261:
262: if (blksize != GET_GLOBAL(drive_g->blksize)) {
263: printf("Unsupported sector size %u\n", blksize);
264: return -1;
265: }
266:
267: dprintf(6, "sectors=%u\n", sectors);
268: printf("%dMB medium detected\n", sectors>>(20-11));
269: return 0;
270: }
271:
272: int
273: cdrom_boot(int cdid)
274: {
275: struct drive_s *drive_g = getDrive(EXTTYPE_CD, cdid);
276: if (!drive_g)
277: return 1;
278:
279: int ret = atapi_is_ready(drive_g);
280: if (ret)
281: dprintf(1, "atapi_is_ready returned %d\n", ret);
282:
283: // Read the Boot Record Volume Descriptor
284: u8 buffer[2048];
285: struct disk_op_s dop;
286: memset(&dop, 0, sizeof(dop));
287: dop.drive_g = drive_g;
288: dop.lba = 0x11;
289: dop.count = 1;
290: dop.buf_fl = MAKE_FLATPTR(GET_SEG(SS), buffer);
291: ret = cdrom_read(&dop);
292: if (ret)
293: return 3;
294:
295: // Validity checks
296: if (buffer[0])
297: return 4;
298: if (strcmp((char*)&buffer[1], "CD001\001EL TORITO SPECIFICATION") != 0)
299: return 5;
300:
301: // ok, now we calculate the Boot catalog address
302: u32 lba = *(u32*)&buffer[0x47];
303:
304: // And we read the Boot Catalog
305: dop.lba = lba;
306: ret = cdrom_read(&dop);
307: if (ret)
308: return 7;
309:
310: // Validation entry
311: if (buffer[0x00] != 0x01)
312: return 8; // Header
313: if (buffer[0x01] != 0x00)
314: return 9; // Platform
315: if (buffer[0x1E] != 0x55)
316: return 10; // key 1
317: if (buffer[0x1F] != 0xAA)
318: return 10; // key 2
319:
320: // Initial/Default Entry
321: if (buffer[0x20] != 0x88)
322: return 11; // Bootable
323:
324: u16 ebda_seg = get_ebda_seg();
325: u8 media = buffer[0x21];
326: SET_EBDA2(ebda_seg, cdemu.media, media);
327:
328: SET_EBDA2(ebda_seg, cdemu.emulated_drive, ADJUST_GLOBAL_PTR(drive_g));
329:
330: u16 boot_segment = *(u16*)&buffer[0x22];
331: if (!boot_segment)
332: boot_segment = 0x07C0;
333: SET_EBDA2(ebda_seg, cdemu.load_segment, boot_segment);
334: SET_EBDA2(ebda_seg, cdemu.buffer_segment, 0x0000);
335:
336: u16 nbsectors = *(u16*)&buffer[0x26];
337: SET_EBDA2(ebda_seg, cdemu.sector_count, nbsectors);
338:
339: lba = *(u32*)&buffer[0x28];
340: SET_EBDA2(ebda_seg, cdemu.ilba, lba);
341:
342: // And we read the image in memory
343: dop.lba = lba;
344: dop.count = DIV_ROUND_UP(nbsectors, 4);
345: dop.buf_fl = MAKE_FLATPTR(boot_segment, 0);
346: ret = cdrom_read(&dop);
347: if (ret)
348: return 12;
349:
350: if (media == 0) {
351: // No emulation requested - return success.
352: SET_EBDA2(ebda_seg, cdemu.emulated_extdrive, EXTSTART_CD + cdid);
353: return 0;
354: }
355:
356: // Emulation of a floppy/harddisk requested
357: if (! CONFIG_CDROM_EMU || !cdemu_drive)
358: return 13;
359:
360: // Set emulated drive id and increase bios installed hardware
361: // number of devices
362: if (media < 4) {
363: // Floppy emulation
364: SET_EBDA2(ebda_seg, cdemu.emulated_extdrive, 0x00);
365: SETBITS_BDA(equipment_list_flags, 0x41);
366:
367: switch (media) {
368: case 0x01: // 1.2M floppy
369: SET_EBDA2(ebda_seg, cdemu.lchs.spt, 15);
370: SET_EBDA2(ebda_seg, cdemu.lchs.cylinders, 80);
371: SET_EBDA2(ebda_seg, cdemu.lchs.heads, 2);
372: break;
373: case 0x02: // 1.44M floppy
374: SET_EBDA2(ebda_seg, cdemu.lchs.spt, 18);
375: SET_EBDA2(ebda_seg, cdemu.lchs.cylinders, 80);
376: SET_EBDA2(ebda_seg, cdemu.lchs.heads, 2);
377: break;
378: case 0x03: // 2.88M floppy
379: SET_EBDA2(ebda_seg, cdemu.lchs.spt, 36);
380: SET_EBDA2(ebda_seg, cdemu.lchs.cylinders, 80);
381: SET_EBDA2(ebda_seg, cdemu.lchs.heads, 2);
382: break;
383: }
384: } else {
385: // Harddrive emulation
386: SET_EBDA2(ebda_seg, cdemu.emulated_extdrive, 0x80);
387: SET_BDA(hdcount, GET_BDA(hdcount) + 1);
388:
389: // Peak at partition table to get chs.
390: struct mbr_s *mbr = (void*)0;
391: u8 sptcyl = GET_FARVAR(boot_segment, mbr->partitions[0].last.sptcyl);
392: u8 cyllow = GET_FARVAR(boot_segment, mbr->partitions[0].last.cyllow);
393: u8 heads = GET_FARVAR(boot_segment, mbr->partitions[0].last.heads);
394:
395: SET_EBDA2(ebda_seg, cdemu.lchs.spt, sptcyl & 0x3f);
396: SET_EBDA2(ebda_seg, cdemu.lchs.cylinders
397: , ((sptcyl<<2)&0x300) + cyllow + 1);
398: SET_EBDA2(ebda_seg, cdemu.lchs.heads, heads + 1);
399: }
400:
401: // everything is ok, so from now on, the emulation is active
402: SET_EBDA2(ebda_seg, cdemu.active, 0x01);
403: dprintf(6, "cdemu media=%d\n", media);
404:
405: return 0;
406: }
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