478 & 15 Mar 2015 & Cornelia Huck & {VIRTIO-129: legacy: clean up virtqueue layout definitions Generalize "Legacy Interfaces: A Note on Virtqueue Layout" to allow for different alignment requirements. Have pci and ccw refer to that section for legacy devices. Remove the double definition of virtqueue alignment (which referred to legacy, but was not tagged as such) from the ccw section. See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / Legacy Interfaces: A Note on Virtqueue Layout}, \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtqueue Configuration / Legacy Interface: A Note on Virtqueue Configuration} and \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Configuring a Virtqueue / Legacy Interface: A Note on Configuring a Virtqueue}. } \\ \hline 479 & 15 Mar 2015 & Cornelia Huck & {VIRTIO-118: ccw: clarify basic channel commands "Basic channel commands" seems to be not as clear as it could, so let's spell out which channel commands we refer to. See \ref{sec:Virtio Transport Options / Virtio over channel I/O / Basic Concepts}. } \\ \hline 479 & 15 Mar 2015 & Cornelia Huck & {VIRTIO-116: ccw: allow WRITE_STATUS to fail We want to be able to fail setting a status on the device (e.g. FEATURES_OK if the device can't work with the features negotiated). The easiest way to do that is to allow the device to fail the WRITE_STATUS command by posting a command reject. See \ref{sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Communicating Status Information}. } \\ \hline 485 & 15 Mar 2015 & Jason Wang & {VIRTIO-135: virtio-ring: comment fixup virtio_ring.h included with spec has this text: /* Support for avail_idx and used_idx fields */ it should really refer to avail_event and used_event. See Appendix \ref{sec:virtio-queue.h}. } \\ \hline 486 & 15 Mar 2015 & Jason Wang & {VIRTIO-136: document idx field in virtqueue used ring Section \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring} The Virtqueue Used Ring listed the idx field, but never documented it. See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring}. } \\ \hline 487 & 15 Mar 2015 & Rusty Russell & {VIRTIO-130: ISR status: Fix incorrect diagram ISR status capability diagram has the "Device Configuration Interrupt " as bit 0, and the "Queue Interrupt" as bit 1. This is the wrong way around: it disagrees with the legacy implementations, as well as the spec elsewhere. All current guests correctly follow the text, fix up the diagram to match. See \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / ISR status capability}. } \\ \hline 488 & 15 Mar 2015 & Rusty Russell & {VIRTIO-133: Change 4.1.5.1.2.1 to device requirement 4.1.5.1.2.1 is incorrectly labelled as a driver requirement; it's self-evidently referring to the device. See \ref{sec:Conformance / Driver Conformance / PCI Driver Conformance}, \ref{sec:Conformance / Device Conformance / PCI Device Conformance} and \ref{devicenormative:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Non-transitional Device With Legacy Driver}. } \\ \hline 504 & 22 Apr 2015 & Rusty Russell & {VIRTIO-137: define the meaning and requirements of the len field. We said what it was for, and noted why. We didn't place any requirements on it, nor clearly spell out the implications of its use. This clarification comes particularly from noticing that QEMU didn't set len correctly, and philosophising over the correct value when an error has occurred. See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring}, \ref{devicenormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring} and \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring}. } \\ \hline 506 & 22 Apr 2015 & Michael S. Tsirkin & {VIRTIO-138: multiple errors: Non-transitional With Legacy virtio 1.0 has two sections titled "Non-transitional Device With Legacy Driver" the first says devices SHOULD fail, the second says devices MUST fail. Clearly a mistake. Other issues: devices don't really fail - they cause drivers to fail. second section seems to be in the wrong place, and also have a section followed by subsection with no explanatory text in between, which is ugly. Finally, this text was originally ritten to handle buggy windows drivers gracefully, but later we changed device IDs so it's not really required there. Might be handy for some other buggy legacy drivers, though no such drivers are known. To fix, drop the duplicate section variant, add some explanatory text, clarify what does "same ID" mean here, and clarify that the work-around is only needed if a buggy driver is known to bind to a transitional device. See \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Non-transitional Device With Legacy Driver: A Note on PCI Device Layout}, \ref{devicenormative:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Non-transitional Device With Legacy Driver} and \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization}. } \\ \hline 508 & 22 Apr 2015 & Michael S. Tsirkin & {VIRTIO-139: pci: missing documentation for dealing with 64 bit config fields pci spec says what width access to use for 32, 16 and 8 bit fields, but does not explicitly say what to do for 32 bit fields. As we have text that says driver must treat 64 bit accesses as non-atomic, this seems to imply driver should always do two 32 bit wide accesses. Let's make this an explicit requirement, and require devices to support this. See \ref{sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout}, \ref{drivernormative:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout}, \ref{devicenormative:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout} and \ref{sec:Conformance / Driver Conformance / PCI Driver Conformance}. } \\ \hline 509 & 22 Apr 2015 & Michael S. Tsirkin & {balloon: MUST -> has to MUST shouldn't be used outside normative statements, that's confusing. Replace with "has to". See \ref{sec:Device Types / Memory Balloon Device / Feature bits}. } \\ \hline 510 & 22 Apr 2015 & Michael S. Tsirkin & {conformance: add VIRTIO-137 statement links Add links to new conformance statements added to resolve VIRTIO-137 (describing used ring entry len usage). See \ref{sec:Conformance / Device Conformance} and \ref{sec:Conformance / Driver Conformance}. } \\ \hline 517 & 22 Apr 2015 & Michael S. Tsirkin & {acknowledgements: contributors+minor fixup acknowledge feedback by Jason Wang, add Richard Sohn who joined the TC, sort acknowledged reviewers alphabetically. See \ref{chap:Acknowledgements}. } \\ \hline 520 & 30 Apr 2015 & James Bottomley & {VIRTIO-140: give explicit guidance on the use of 64 bit fields Just saying 64 bit fields may not be atomic is true, but less helpful than it might be. Add explicit guidance about what the consequences of non-atomicity are. See \ref{sec:Creating New Device Types / What Device Configuration Space Layout?} } \\ \hline 521 & 30 Apr 2015 & Rusty Russell & {VIRTIO-134: Spell out details of indirect elements in chains 1) It's implied that a chain terminates with an indirect descriptor (since VIRTIO-15) but we didn't spell out that a device MUST NOT continue it. 2) We allow [direct]->[direct]->[indirect], and qemu and bhyve both accept it. Make it clear that this is valid, thus devices MUST handle it. See \ref{drivernormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table / Indirect Descriptors} and \ref{devicenormative:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table / Indirect Descriptors} } \\ \hline 522 & 30 Apr 2015 & Michael S. Tsirkin & {VIRTIO-141: used ring: specify legacy behaviour for len field many hypervisors implemented len field incorrectly. Document existing bugs in the legacy sections. See \ref{sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring/ Legacy Interface: The Virtqueue Used Ring}, \ref{sec:Device Types / Network Device / Device Operation / Legacy Interface: Device Operation}, \ref{sec:Device Types / Block Device / Device Operation / Legacy Interface: Device Operation}, \ref{sec:Device Types / Console Device / Device Operation / Legacy Interface: Device Operation}, \ref{sec:Device Types / Memory Balloon Device / Device Operation / Legacy Interface: Device Operation}, \ref{sec:Device Types / SCSI Host Device / Device Operation / Legacy Interface: Device Operation} and \ref{sec:Conformance / Legacy Interface: Transitional Device and Transitional Driver Conformance}. } \\ \hline 523 & 30 Apr 2015 & Michael S. Tsirkin & {VIRTIO-142: entropy device: typo fix Current text: "The driver MUST examine the length written by the driver" makes no sense. length is written by the device. See \ref{drivernormative:Device Types / Entropy Device / Device Operation}. } \\ \hline 526 & 18 May 2015 & Michael S. Tsirkin & {VIRTIO-143: balloon: transitional device support Support a transitional balloon device: this has the advantage of supporting existing drivers, transparently, as well as transports that don't allow mixing virtio 0 and virtio 1 devices. And balloon is an easy device to test, so it's also useful for people to test virtio core handling of transitional devices. Three issues with legacy hypervisors have been identified: \begin{enumerate} \item Actual value is actually used, and is necessary for management to work. Luckily 4 byte config space writes are now atomic. When using old guests, hypervisors can detect access to the last byte. When using old hypervisors, drivers can use atomic 4-byte accesses. \item Hypervisors actually didn't ignore the stats from the first buffer supplied. This means the values there would be incorrect until hypervisor resends the request. Add a note suggesting hypervisors ignore the 1st buffer. \item QEMU simply over-writes stats from each buffer it gets. Thus if driver supplies a different subset of stats on each request, stale values will be there. Require drivers to supply the same subset on each request. This also gives us a simple way to figure out which stats are supported. \end{enumerate} See \ref{sec:Device Types / Memory Balloon Device}, \ref{devicenormative:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery}, \ref{sec:Conformance / Driver Conformance / Traditional Memory Balloon Driver Conformance}, \ref{sec:Conformance / Device Conformance / Traditional Memory Balloon Device Conformance}, \ref{sec:Conformance / Legacy Interface: Transitional Device and Transitional Driver Conformance}, \ref{sec:Conformance / Device Conformance} and \ref{sec:Conformance / Driver Conformance}. } \\ \hline 527 & 18 May 2015 & Michael S. Tsirkin & {VIRTIO-126: document deflate on oom Document the new option, and also clarify behaviour without it. In particular, actual field is not the actual number of pages in the balloon as driver might do inflate followed by deflate. Also, device isn't always driven by interrupts, driver can inflate/deflate in response to e.g. memory compaction. See \ref{sec:Device Types / Memory Balloon Device / Feature bits}, \ref{sec:Device Types / Memory Balloon Device / Device Operation} and \ref{drivernormative:Device Types / Memory Balloon Device / Device Operation}. } \\ \hline 528 & 18 May 2015 & Michael S. Tsirkin & {VIRTIO-123: network device: xmit/receive cleanup Fix up multiple issues in xmit/receive sections: \begin{itemize} \item drop MAY/MUST/SHOULD outside normative statements \item spell out conformance requirements for both drivers and devices, for xmit and receive paths \item document the missing VIRTIO_NET_HDR_F_DATA_VALID \item document handling of unrecognized flag bits so we can extend flags in the future, similar to VIRTIO_NET_HDR_F_DATA_VALID \end{itemize} \ref{sec:Device Types / Network Device / Device Initialization}, \ref{drivernormative:Device Types / Network Device / Device Operation / Packet Transmission}, \ref{devicenormative:Device Types / Network Device / Device Operation / Packet Transmission}, \ref{sec:Device Types / Network Device / Device Operation / Processing of Incoming Packets}, \ref{sec:Conformance / Driver Conformance / Network Driver Conformance} and \ref{sec:Conformance / Device Conformance / Network Device Conformance}. } \\ \hline 529 & 18 May 2015 & Michael S. Tsirkin & {VIRTIO-124: network device: document VIRTIO_NET_F_CTRL_RX_EXTRA See \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Packet Receive Filtering}, \ref{sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering}, \ref{sec:Conformance / Driver Conformance / Network Driver Conformance} and \ref{sec:Conformance / Device Conformance / Network Device Conformance}. } \\ \hline '>315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1498 1499 1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511 1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527 1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541 1542 1543 1544 1545 1546 1547 1548 1549 1550 1551 1552 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1585 1586 1587 1588 1589 1590 1591 1592 1593 1594 1595 1596 1597 1598 1599 1600 1601 1602 1603 1604 1605 1606 1607 1608 1609 1610 1611 1612 1613 1614 1615 1616 1617 1618 1619 1620 1621 1622 1623 
/* i830_dma.c -- DMA support for the I830 -*- linux-c -*-
 * Created: Mon Dec 13 01:50:01 1999 by jhartmann@precisioninsight.com
 *
 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors: Rickard E. (Rik) Faith <faith@valinux.com>
 *	    Jeff Hartmann <jhartmann@valinux.com>
 *	    Keith Whitwell <keith@tungstengraphics.com>
 *	    Abraham vd Merwe <abraham@2d3d.co.za>
 *
 */

#include "i830.h"
#include "drmP.h"
#include "drm.h"
#include "i830_drm.h"
#include "i830_drv.h"
#include <linux/interrupt.h>	/* For task queue support */
#include <linux/pagemap.h>     /* For FASTCALL on unlock_page() */
#include <linux/delay.h>
#include <asm/uaccess.h>

#ifdef DO_MUNMAP_4_ARGS
#define DO_MUNMAP(m, a, l)	do_munmap(m, a, l, 1)
#else
#define DO_MUNMAP(m, a, l)	do_munmap(m, a, l)
#endif

#define I830_BUF_FREE		2
#define I830_BUF_CLIENT		1
#define I830_BUF_HARDWARE      	0

#define I830_BUF_UNMAPPED 0
#define I830_BUF_MAPPED   1

static inline void i830_print_status_page(drm_device_t *dev)
{
   	drm_device_dma_t *dma = dev->dma;
      	drm_i830_private_t *dev_priv = dev->dev_private;
	u32 *temp = dev_priv->hw_status_page;
   	int i;

   	DRM_DEBUG(  "hw_status: Interrupt Status : %x\n", temp[0]);
   	DRM_DEBUG(  "hw_status: LpRing Head ptr : %x\n", temp[1]);
   	DRM_DEBUG(  "hw_status: IRing Head ptr : %x\n", temp[2]);
      	DRM_DEBUG(  "hw_status: Reserved : %x\n", temp[3]);
   	DRM_DEBUG(  "hw_status: Driver Counter : %d\n", temp[5]);
   	for(i = 9; i < dma->buf_count + 9; i++) {
	   	DRM_DEBUG( "buffer status idx : %d used: %d\n", i - 9, temp[i]);
	}
}

static drm_buf_t *i830_freelist_get(drm_device_t *dev)
{
   	drm_device_dma_t *dma = dev->dma;
	int		 i;
   	int 		 used;
   
	/* Linear search might not be the best solution */

   	for (i = 0; i < dma->buf_count; i++) {
	   	drm_buf_t *buf = dma->buflist[ i ];
	   	drm_i830_buf_priv_t *buf_priv = buf->dev_private;
		/* In use is already a pointer */
	   	used = cmpxchg(buf_priv->in_use, I830_BUF_FREE, 
			       I830_BUF_CLIENT);
	   	if(used == I830_BUF_FREE) {
			return buf;
		}
	}
   	return NULL;
}

/* This should only be called if the buffer is not sent to the hardware
 * yet, the hardware updates in use for us once its on the ring buffer.
 */

static int i830_freelist_put(drm_device_t *dev, drm_buf_t *buf)
{
   	drm_i830_buf_priv_t *buf_priv = buf->dev_private;
   	int used;
   
   	/* In use is already a pointer */
   	used = cmpxchg(buf_priv->in_use, I830_BUF_CLIENT, I830_BUF_FREE);
   	if(used != I830_BUF_CLIENT) {
	   	DRM_ERROR("Freeing buffer thats not in use : %d\n", buf->idx);
	   	return -EINVAL;
	}
   
   	return 0;
}

static struct file_operations i830_buffer_fops = {
	.open	 = DRM(open),
	.flush	 = DRM(flush),
	.release = DRM(release),
	.ioctl	 = DRM(ioctl),
	.mmap	 = i830_mmap_buffers,
	.fasync  = DRM(fasync),
};

int i830_mmap_buffers(struct file *filp, struct vm_area_struct *vma)
{
	drm_file_t	    *priv	  = filp->private_data;
	drm_device_t	    *dev;
	drm_i830_private_t  *dev_priv;
	drm_buf_t           *buf;
	drm_i830_buf_priv_t *buf_priv;

	lock_kernel();
	dev	 = priv->dev;
	dev_priv = dev->dev_private;
	buf      = dev_priv->mmap_buffer;
	buf_priv = buf->dev_private;
   
	vma->vm_flags |= (VM_IO | VM_DONTCOPY);
	vma->vm_file = filp;
   
   	buf_priv->currently_mapped = I830_BUF_MAPPED;
	unlock_kernel();

	if (remap_page_range(DRM_RPR_ARG(vma) vma->vm_start,
			     VM_OFFSET(vma),
			     vma->vm_end - vma->vm_start,
			     vma->vm_page_prot)) return -EAGAIN;
	return 0;
}

static int i830_map_buffer(drm_buf_t *buf, struct file *filp)
{
	drm_file_t	  *priv	  = filp->private_data;
	drm_device_t	  *dev	  = priv->dev;
	drm_i830_buf_priv_t *buf_priv = buf->dev_private;
      	drm_i830_private_t *dev_priv = dev->dev_private;
   	struct file_operations *old_fops;
	unsigned long virtual;
	int retcode = 0;

	if(buf_priv->currently_mapped == I830_BUF_MAPPED) return -EINVAL;

	down_write( &current->mm->mmap_sem );
	old_fops = filp->f_op;
	filp->f_op = &i830_buffer_fops;
	dev_priv->mmap_buffer = buf;
	virtual = do_mmap(filp, 0, buf->total, PROT_READ|PROT_WRITE,
			    MAP_SHARED, buf->bus_address);
	dev_priv->mmap_buffer = NULL;
	filp->f_op = old_fops;
	if (IS_ERR((void *)virtual)) {		/* ugh */
		/* Real error */
		DRM_ERROR("mmap error\n");
		retcode = virtual;
		buf_priv->virtual = NULL;
	} else {
		buf_priv->virtual = (void __user *)virtual;
	}
	up_write( &current->mm->mmap_sem );

	return retcode;
}

static int i830_unmap_buffer(drm_buf_t *buf)
{
	drm_i830_buf_priv_t *buf_priv = buf->dev_private;
	int retcode = 0;

	if(buf_priv->currently_mapped != I830_BUF_MAPPED) 
		return -EINVAL;

	down_write(&current->mm->mmap_sem);
	retcode = DO_MUNMAP(current->mm,
			    (unsigned long)buf_priv->virtual,
			    (size_t) buf->total);
	up_write(&current->mm->mmap_sem);

   	buf_priv->currently_mapped = I830_BUF_UNMAPPED;
   	buf_priv->virtual = NULL;

	return retcode;
}

static int i830_dma_get_buffer(drm_device_t *dev, drm_i830_dma_t *d, 
			       struct file *filp)
{
	drm_buf_t	  *buf;
	drm_i830_buf_priv_t *buf_priv;
	int retcode = 0;

	buf = i830_freelist_get(dev);
	if (!buf) {
		retcode = -ENOMEM;
	   	DRM_DEBUG("retcode=%d\n", retcode);
		return retcode;
	}
   
	retcode = i830_map_buffer(buf, filp);
	if(retcode) {
		i830_freelist_put(dev, buf);
	   	DRM_ERROR("mapbuf failed, retcode %d\n", retcode);
		return retcode;
	}
	buf->filp = filp;
	buf_priv = buf->dev_private;	
	d->granted = 1;
   	d->request_idx = buf->idx;
   	d->request_size = buf->total;
   	d->virtual = buf_priv->virtual;

	return retcode;
}

int i830_dma_cleanup(drm_device_t *dev)
{
	drm_device_dma_t *dma = dev->dma;

	/* Make sure interrupts are disabled here because the uninstall ioctl
	 * may not have been called from userspace and after dev_private
	 * is freed, it's too late.
	 */
	if (dev->irq_enabled) DRM(irq_uninstall)(dev);

	if (dev->dev_private) {
		int i;
	   	drm_i830_private_t *dev_priv = 
	     		(drm_i830_private_t *) dev->dev_private;
	   
	   	if (dev_priv->ring.virtual_start) {
		   	DRM(ioremapfree)((void *) dev_priv->ring.virtual_start,
					 dev_priv->ring.Size, dev);
		}
	   	if (dev_priv->hw_status_page) {
			pci_free_consistent(dev->pdev, PAGE_SIZE,
					    dev_priv->hw_status_page,
					    dev_priv->dma_status_page);
		   	/* Need to rewrite hardware status page */
		   	I830_WRITE(0x02080, 0x1ffff000);
		}

	   	DRM(free)(dev->dev_private, sizeof(drm_i830_private_t), 
			 DRM_MEM_DRIVER);
	   	dev->dev_private = NULL;

		for (i = 0; i < dma->buf_count; i++) {
			drm_buf_t *buf = dma->buflist[ i ];
			drm_i830_buf_priv_t *buf_priv = buf->dev_private;
			if ( buf_priv->kernel_virtual && buf->total )
				DRM(ioremapfree)(buf_priv->kernel_virtual, buf->total, dev);
		}
	}
   	return 0;
}

int i830_wait_ring(drm_device_t *dev, int n, const char *caller)
{
   	drm_i830_private_t *dev_priv = dev->dev_private;
   	drm_i830_ring_buffer_t *ring = &(dev_priv->ring);
   	int iters = 0;
   	unsigned long end;
	unsigned int last_head = I830_READ(LP_RING + RING_HEAD) & HEAD_ADDR;

	end = jiffies + (HZ*3);
   	while (ring->space < n) {	
	   	ring->head = I830_READ(LP_RING + RING_HEAD) & HEAD_ADDR;
	   	ring->space = ring->head - (ring->tail+8);
		if (ring->space < 0) ring->space += ring->Size;
	   
		if (ring->head != last_head) {
			end = jiffies + (HZ*3);
			last_head = ring->head;
		}
	  
	   	iters++;
		if(time_before(end, jiffies)) {
		   	DRM_ERROR("space: %d wanted %d\n", ring->space, n);
		   	DRM_ERROR("lockup\n");
		   	goto out_wait_ring;
		}
		udelay(1);
		dev_priv->sarea_priv->perf_boxes |= I830_BOX_WAIT;
	}

out_wait_ring:   
   	return iters;
}

static void i830_kernel_lost_context(drm_device_t *dev)
{
      	drm_i830_private_t *dev_priv = dev->dev_private;
   	drm_i830_ring_buffer_t *ring = &(dev_priv->ring);
      
   	ring->head = I830_READ(LP_RING + RING_HEAD) & HEAD_ADDR;
     	ring->tail = I830_READ(LP_RING + RING_TAIL) & TAIL_ADDR;
     	ring->space = ring->head - (ring->tail+8);
     	if (ring->space < 0) ring->space += ring->Size;

	if (ring->head == ring->tail)
		dev_priv->sarea_priv->perf_boxes |= I830_BOX_RING_EMPTY;
}

static int i830_freelist_init(drm_device_t *dev, drm_i830_private_t *dev_priv)
{
      	drm_device_dma_t *dma = dev->dma;
   	int my_idx = 36;
   	u32 *hw_status = (u32 *)(dev_priv->hw_status_page + my_idx);
   	int i;

   	if(dma->buf_count > 1019) {
	   	/* Not enough space in the status page for the freelist */
	   	return -EINVAL;
	}

   	for (i = 0; i < dma->buf_count; i++) {
	   	drm_buf_t *buf = dma->buflist[ i ];
	   	drm_i830_buf_priv_t *buf_priv = buf->dev_private;

	   	buf_priv->in_use = hw_status++;
	   	buf_priv->my_use_idx = my_idx;
	   	my_idx += 4;

	   	*buf_priv->in_use = I830_BUF_FREE;

		buf_priv->kernel_virtual = DRM(ioremap)(buf->bus_address, 
							buf->total, dev);
	}
	return 0;
}

static int i830_dma_initialize(drm_device_t *dev, 
			       drm_i830_private_t *dev_priv,
			       drm_i830_init_t *init)
{
	struct list_head *list;

   	memset(dev_priv, 0, sizeof(drm_i830_private_t));

	list_for_each(list, &dev->maplist->head) {
		drm_map_list_t *r_list = list_entry(list, drm_map_list_t, head);
		if( r_list->map &&
		    r_list->map->type == _DRM_SHM &&
		    r_list->map->flags & _DRM_CONTAINS_LOCK ) {
			dev_priv->sarea_map = r_list->map;
 			break;
 		}
 	}