xref: /titanic_50/usr/src/uts/intel/io/agpmaster/agpmaster.c (revision e07d9cb85217949d497b02d7211de8a197d2f2eb)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 /*
30  * Misc module for AGP master device support
31  */
32 
33 #include <sys/modctl.h>
34 #include <sys/pci.h>
35 #include <sys/stat.h>
36 #include <sys/file.h>
37 #include <sys/types.h>
38 #include <sys/dditypes.h>
39 #include <sys/sunddi.h>
40 #include <sys/agpgart.h>
41 #include <sys/agp/agpdefs.h>
42 #include <sys/agp/agpmaster_io.h>
43 
44 #define	PGTBL_CTL	0x2020	/* Page table control register */
45 #define	I8XX_FB_BAR	1
46 #define	I8XX_MMIO_BAR	2
47 #define	I8XX_PTE_OFFSET	0x10000
48 #define	I915_MMADR	1	/* mem-mapped registers BAR */
49 #define	I915_GMADR	3	/* graphics mem BAR */
50 #define	I915_GTTADDR	4	/* GTT BAR */
51 #define	I965_GTTMMADR	1	/* mem-mapped registers BAR + GTT */
52 #define	I965_GMADR	2	/* graphics mem BAR */
53 /* In 965 1MB GTTMMADR, GTT reside in the latter 512KB */
54 #define	I965_GTT_OFFSET	0x80000
55 #define	GTT_SIZE_MASK	0xe
56 #define	GTT_512KB	(0 << 1)
57 #define	GTT_256KB	(1 << 1)
58 #define	GTT_128KB	(2 << 1)
59 
60 #define	MMIO_BASE(x)	(x)->agpm_data.agpm_gtt.gtt_mmio_base
61 #define	MMIO_HANDLE(x)	(x)->agpm_data.agpm_gtt.gtt_mmio_handle
62 #define	GTT_ADDR(x)	(x)->agpm_data.agpm_gtt.gtt_addr
63 #define	APER_BASE(x)	(x)->agpm_data.agpm_gtt.gtt_info.igd_aperbase
64 
65 #define	AGPM_WRITE(x, off, val) \
66     ddi_put32(MMIO_HANDLE(x), (uint32_t *)(MMIO_BASE(x) + (off)), (val));
67 
68 #define	AGPM_READ(x, off) \
69     ddi_get32(MMIO_HANDLE(x), (uint32_t *)(MMIO_BASE(x) + (off)));
70 
71 #ifdef DEBUG
72 #define	CONFIRM(value) ASSERT(value)
73 #else
74 #define	CONFIRM(value) if (!(value)) return (EINVAL)
75 #endif
76 
77 int agpm_debug = 0;
78 #define	AGPM_DEBUG(args)	if (agpm_debug >= 1) cmn_err args
79 
80 /*
81  * Whether it is a Intel integrated graphics card
82  */
83 #define	IS_IGD(agpmaster) ((agpmaster->agpm_dev_type == DEVICE_IS_I810) || \
84 	(agpmaster->agpm_dev_type == DEVICE_IS_I830))
85 
86 
87 /* Intel 915 and 945 series */
88 #define	IS_INTEL_915(agpmaster) ((agpmaster->agpm_id == INTEL_IGD_915) || \
89 	(agpmaster->agpm_id == INTEL_IGD_915GM) || \
90 	(agpmaster->agpm_id == INTEL_IGD_945) || \
91 	(agpmaster->agpm_id == INTEL_IGD_945GM))
92 
93 /* Intel 965 series */
94 #define	IS_INTEL_965(agpmaster) ((agpmaster->agpm_id == INTEL_IGD_946GZ) || \
95 	(agpmaster->agpm_id == INTEL_IGD_965G1) || \
96 	(agpmaster->agpm_id == INTEL_IGD_965Q) || \
97 	(agpmaster->agpm_id == INTEL_IGD_965G2) || \
98 	(agpmaster->agpm_id == INTEL_IGD_965GM))
99 
100 static struct modlmisc modlmisc = {
101 	&mod_miscops, "AGP master interfaces v%I%"
102 };
103 
104 static struct modlinkage modlinkage = {
105 	MODREV_1, (void *)&modlmisc, NULL
106 };
107 
108 static ddi_device_acc_attr_t i8xx_dev_access = {
109 	DDI_DEVICE_ATTR_V0,
110 	DDI_NEVERSWAP_ACC,
111 	DDI_STRICTORDER_ACC
112 };
113 
114 static off_t agpmaster_cap_find(ddi_acc_handle_t);
115 static int detect_i8xx_device(agp_master_softc_t *);
116 static int detect_agp_devcice(agp_master_softc_t *, ddi_acc_handle_t);
117 static int i8xx_add_to_gtt(gtt_impl_t *, igd_gtt_seg_t);
118 static void i8xx_remove_from_gtt(gtt_impl_t *, igd_gtt_seg_t);
119 
120 int
121 _init(void)
122 {
123 	int	err;
124 
125 	if ((err = mod_install(&modlinkage)) != 0)
126 		return (err);
127 
128 	return (0);
129 }
130 
131 int
132 _fini(void)
133 {
134 	int	err;
135 
136 	if ((err = mod_remove(&modlinkage)) != 0)
137 		return (err);
138 
139 	return (0);
140 }
141 
142 int
143 _info(struct modinfo *modinfop)
144 {
145 	return (mod_info(&modlinkage, modinfop));
146 }
147 
148 /*
149  * Minor node is not removed here, since the caller (xx_attach) is
150  * responsible for removing all nodes.
151  */
152 void
153 agpmaster_detach(agp_master_softc_t **master_softcp)
154 {
155 	agp_master_softc_t *master_softc;
156 
157 	ASSERT(master_softcp);
158 	master_softc = *master_softcp;
159 
160 	/* intel integrated device */
161 	if (IS_IGD(master_softc)) {
162 		if (MMIO_HANDLE(master_softc) != NULL) {
163 			ddi_regs_map_free(&MMIO_HANDLE(master_softc));
164 		}
165 	}
166 
167 	kmem_free(master_softc, sizeof (agp_master_softc_t));
168 	master_softc = NULL;
169 
170 	return;
171 
172 }
173 
174 /*
175  * 965 has a fixed GTT table size (512KB), so check to see the actual aperture
176  * size. Aperture size = GTT table size * 1024.
177  */
178 static off_t
179 i965_apersize(agp_master_softc_t *agpmaster)
180 {
181 	off_t apersize;
182 
183 	apersize = AGPM_READ(agpmaster, PGTBL_CTL);
184 	AGPM_DEBUG((CE_NOTE, "i965_apersize: PGTBL_CTL = %lx", apersize));
185 	switch (apersize & GTT_SIZE_MASK) {
186 	case GTT_512KB:
187 		apersize = 512;
188 		break;
189 	case GTT_256KB:
190 		apersize = 256;
191 		break;
192 	case GTT_128KB:
193 		apersize = 128;
194 		break;
195 	default:
196 		AGPM_DEBUG((CE_WARN,
197 		    "i965_apersize: invalid GTT size in PGTBL_CTL"));
198 	}
199 	apersize = MB2BYTES(apersize);
200 	return (apersize);
201 }
202 
203 #define	CHECK_STATUS(status)	\
204     if (status != DDI_SUCCESS) { \
205 	    AGPM_DEBUG((CE_WARN, \
206 		"set_gtt_mmio: regs_map_setup error")); \
207 	    return (-1); \
208 }
209 /*
210  * Set gtt_addr, gtt_mmio_base, igd_apersize, igd_aperbase and igd_devid
211  * according to chipset.
212  */
213 static int
214 set_gtt_mmio(dev_info_t *devi, agp_master_softc_t *agpmaster, ddi_acc_handle_t
215     pci_acc_hdl)
216 {
217 	off_t apersize;
218 	uint32_t value;
219 	off_t conf_off; /* offset in PCI conf space for aperture */
220 	int status;
221 
222 	if (IS_INTEL_965(agpmaster)) {
223 		status = ddi_regs_map_setup(devi, I965_GTTMMADR,
224 		    &MMIO_BASE(agpmaster), 0, 0, &i8xx_dev_access,
225 		    &MMIO_HANDLE(agpmaster));
226 		CHECK_STATUS(status);
227 		GTT_ADDR(agpmaster) = MMIO_BASE(agpmaster) + I965_GTT_OFFSET;
228 
229 		conf_off = I915_CONF_GMADR;
230 		apersize = i965_apersize(agpmaster);
231 		/* make this the last line, to clear follow-up status check */
232 		status = DDI_SUCCESS;
233 
234 	} else if (IS_INTEL_915(agpmaster)) {
235 		status = ddi_regs_map_setup(devi, I915_GTTADDR,
236 		    &GTT_ADDR(agpmaster), 0, 0, &i8xx_dev_access,
237 		    &MMIO_HANDLE(agpmaster));
238 		CHECK_STATUS(status);
239 
240 		status = ddi_regs_map_setup(devi, I915_MMADR,
241 		    &MMIO_BASE(agpmaster), 0, 0, &i8xx_dev_access,
242 		    &MMIO_HANDLE(agpmaster));
243 		CHECK_STATUS(status);
244 
245 		conf_off = I915_CONF_GMADR;
246 		status = ddi_dev_regsize(devi, I915_GMADR, &apersize);
247 	} else {
248 		/* I8XX series */
249 		status = ddi_regs_map_setup(devi, I8XX_MMIO_BAR,
250 		    &MMIO_BASE(agpmaster), 0, 0, &i8xx_dev_access,
251 		    &MMIO_HANDLE(agpmaster));
252 		CHECK_STATUS(status);
253 
254 		GTT_ADDR(agpmaster) = MMIO_BASE(agpmaster) + I8XX_PTE_OFFSET;
255 		conf_off = I8XX_CONF_GMADR;
256 		status = ddi_dev_regsize(devi, I8XX_FB_BAR, &apersize);
257 		CHECK_STATUS(status);
258 	}
259 
260 	/*
261 	 * if memory size is smaller than a certain value, it means
262 	 * the register set number for graphics memory range might
263 	 * be wrong
264 	 */
265 	if (status != DDI_SUCCESS || apersize < 0x400000) {
266 		AGPM_DEBUG((CE_WARN,
267 		    "set_gtt_mmio: ddi_dev_regsize error"));
268 		return (-1);
269 	}
270 
271 	agpmaster->agpm_data.agpm_gtt.gtt_info.igd_apersize =
272 	    BYTES2MB(apersize);
273 
274 	/* get GTT base */
275 	value = pci_config_get32(pci_acc_hdl, conf_off);
276 
277 	APER_BASE(agpmaster) = value & GTT_BASE_MASK;
278 	agpmaster->agpm_data.agpm_gtt.gtt_info.igd_devid =
279 	    agpmaster->agpm_id;
280 	AGPM_DEBUG((CE_NOTE, "set_gtt_mmio: aperbase = %x, apersize = %lx, "
281 	    "gtt_addr = %p, mmio_base = %p", APER_BASE(agpmaster), apersize,
282 	    (void *)GTT_ADDR(agpmaster), (void *)MMIO_BASE(agpmaster)));
283 	return (0);
284 }
285 
286 /*
287  * Try to initialize agp master.
288  * 0 is returned if the device is successfully initialized. AGP master soft
289  * state is returned in master_softcp if needed.
290  * Otherwise -1 is returned and *master_softcp is set to NULL.
291  */
292 int
293 agpmaster_attach(dev_info_t *devi, agp_master_softc_t **master_softcp,
294     ddi_acc_handle_t pci_acc_hdl, minor_t minor)
295 {
296 	int instance;
297 	int status;
298 	agp_master_softc_t *agpmaster;
299 	char buf[80];
300 
301 
302 	ASSERT(pci_acc_hdl);
303 	*master_softcp = NULL;
304 	agpmaster = (agp_master_softc_t *)
305 	    kmem_zalloc(sizeof (agp_master_softc_t), KM_SLEEP);
306 
307 	agpmaster->agpm_id =
308 	    pci_config_get32(pci_acc_hdl, PCI_CONF_VENID);
309 	agpmaster->agpm_acc_hdl = pci_acc_hdl;
310 
311 	if (!detect_i8xx_device(agpmaster)) {
312 		/* Intel 8XX, 915, 945 and 965 series */
313 		if (set_gtt_mmio(devi, agpmaster, pci_acc_hdl) != 0)
314 			goto fail;
315 	} else if (detect_agp_devcice(agpmaster, pci_acc_hdl)) {
316 		/* non IGD or AGP devices, AMD64 gart */
317 		AGPM_DEBUG((CE_WARN,
318 		    "agpmaster_attach: neither IGD or AGP devices exists"));
319 		agpmaster_detach(&agpmaster);
320 		return (0);
321 	}
322 
323 	/* create minor node for IGD or AGP device */
324 	instance = ddi_get_instance(devi);
325 
326 	(void) sprintf(buf, "%s%d", AGPMASTER_NAME, instance);
327 	status = ddi_create_minor_node(devi, buf, S_IFCHR, minor,
328 	    DDI_NT_AGP_MASTER, 0);
329 
330 	if (status != DDI_SUCCESS) {
331 		AGPM_DEBUG((CE_WARN,
332 		    "agpmaster_attach: create agpmaster node failed"));
333 		goto fail;
334 	}
335 
336 	*master_softcp = agpmaster;
337 	return (0);
338 fail:
339 	agpmaster_detach(&agpmaster);
340 	return (-1);
341 }
342 
343 /*
344  * Currently, it handles ioctl requests related with agp master device for
345  * layered driver (agpgart) only.
346  */
347 /*ARGSUSED*/
348 int
349 agpmaster_ioctl(dev_t dev, int cmd, intptr_t data, int mode, cred_t *cred,
350     int *rval, agp_master_softc_t *softc)
351 {
352 	uint32_t base;
353 	uint32_t addr;
354 	igd_gtt_seg_t seg;
355 	agp_info_t info;
356 	uint32_t value;
357 	off_t cap;
358 	uint32_t command;
359 	static char kernel_only[] =
360 	    "agpmaster_ioctl: %s is a kernel only ioctl";
361 
362 	CONFIRM(softc);
363 
364 	switch (cmd) {
365 	case DEVICE_DETECT:
366 		if (!(mode & FKIOCTL)) {
367 			AGPM_DEBUG((CE_CONT, kernel_only, "DEVICE_DETECT"));
368 			return (ENXIO);
369 		}
370 
371 		if (ddi_copyout(&softc->agpm_dev_type,
372 		    (void *)data, sizeof (int), mode))
373 			return (EFAULT);
374 		break;
375 	case AGP_MASTER_SETCMD:
376 		if (!(mode & FKIOCTL)) {
377 			AGPM_DEBUG((CE_CONT, kernel_only, "AGP_MASTER_SETCMD"));
378 			return (ENXIO);
379 		}
380 
381 		CONFIRM(softc->agpm_dev_type == DEVICE_IS_AGP);
382 		CONFIRM(softc->agpm_data.agpm_acaptr);
383 
384 		if (ddi_copyin((void *)data, &command,
385 		    sizeof (uint32_t), mode))
386 			return (EFAULT);
387 
388 		pci_config_put32(softc->agpm_acc_hdl,
389 		    softc->agpm_data.agpm_acaptr + AGP_CONF_COMMAND,
390 		    command);
391 		break;
392 	case AGP_MASTER_GETINFO:
393 		if (!(mode & FKIOCTL)) {
394 			AGPM_DEBUG((CE_CONT, kernel_only,
395 			    "AGP_MASTER_GETINFO"));
396 			return (ENXIO);
397 		}
398 
399 		CONFIRM(softc->agpm_dev_type == DEVICE_IS_AGP);
400 		CONFIRM(softc->agpm_data.agpm_acaptr);
401 
402 		cap = softc->agpm_data.agpm_acaptr;
403 		value = pci_config_get32(softc->agpm_acc_hdl, cap);
404 		info.agpi_version.agpv_major = (uint16_t)((value >> 20) & 0xf);
405 		info.agpi_version.agpv_minor = (uint16_t)((value >> 16) & 0xf);
406 		info.agpi_devid = softc->agpm_id;
407 		info.agpi_mode = pci_config_get32(
408 		    softc->agpm_acc_hdl, cap + AGP_CONF_STATUS);
409 
410 		if (ddi_copyout(&info, (void *)data,
411 		    sizeof (agp_info_t), mode))
412 			return (EFAULT);
413 		break;
414 	case I810_SET_GTT_BASE:
415 		if (!(mode & FKIOCTL)) {
416 			AGPM_DEBUG((CE_CONT, kernel_only, "I810_SET_GTT_ADDR"));
417 			return (ENXIO);
418 		}
419 
420 		CONFIRM(softc->agpm_dev_type == DEVICE_IS_I810);
421 
422 		if (ddi_copyin((void *)data, &base, sizeof (uint32_t), mode))
423 			return (EFAULT);
424 
425 		/* enables page table */
426 		addr = (base & GTT_BASE_MASK) | GTT_TABLE_VALID;
427 
428 		AGPM_WRITE(softc, PGTBL_CTL, addr);
429 		break;
430 	case I8XX_GET_INFO:
431 		if (!(mode & FKIOCTL)) {
432 			AGPM_DEBUG((CE_CONT, kernel_only, "I8XX_GET_INFO"));
433 			return (ENXIO);
434 		}
435 
436 		CONFIRM(IS_IGD(softc));
437 
438 		if (ddi_copyout(&softc->agpm_data.agpm_gtt.gtt_info,
439 		    (void *)data, sizeof (igd_info_t), mode))
440 			return (EFAULT);
441 		break;
442 	case I8XX_ADD2GTT:
443 		if (!(mode & FKIOCTL)) {
444 			AGPM_DEBUG((CE_CONT, kernel_only, "I8XX_ADD2GTT"));
445 			return (ENXIO);
446 		}
447 
448 		CONFIRM(IS_IGD(softc));
449 
450 		if (ddi_copyin((void *)data, &seg,
451 		    sizeof (igd_gtt_seg_t), mode))
452 			return (EFAULT);
453 
454 		if (i8xx_add_to_gtt(&softc->agpm_data.agpm_gtt, seg))
455 			return (EINVAL);
456 		break;
457 	case I8XX_REM_GTT:
458 		if (!(mode & FKIOCTL)) {
459 			AGPM_DEBUG((CE_CONT, kernel_only, "I8XX_REM_GTT"));
460 			return (ENXIO);
461 		}
462 
463 		CONFIRM(IS_IGD(softc));
464 
465 		if (ddi_copyin((void *)data, &seg,
466 		    sizeof (igd_gtt_seg_t), mode))
467 			return (EFAULT);
468 
469 		i8xx_remove_from_gtt(&softc->agpm_data.agpm_gtt, seg);
470 		break;
471 	case I8XX_UNCONFIG:
472 		if (!(mode & FKIOCTL)) {
473 			AGPM_DEBUG((CE_CONT, kernel_only, "I8XX_UNCONFIG"));
474 			return (ENXIO);
475 		}
476 
477 		CONFIRM(IS_IGD(softc));
478 
479 		if (softc->agpm_dev_type == DEVICE_IS_I810)
480 			AGPM_WRITE(softc, PGTBL_CTL, 0);
481 		/*
482 		 * may need to clear all gtt entries here for i830 series,
483 		 * but may not be necessary
484 		 */
485 		break;
486 	}
487 	return (0);
488 }
489 
490 /*
491  * If AGP cap pointer is successfully found, none-zero value is returned.
492  * Otherwise 0 is returned.
493  */
494 static off_t
495 agpmaster_cap_find(ddi_acc_handle_t acc_handle)
496 {
497 	off_t		nextcap;
498 	uint32_t	ncapid;
499 	uint8_t		value;
500 
501 	/* check if this device supports capibility pointer */
502 	value = (uint8_t)(pci_config_get16(acc_handle, PCI_CONF_STAT)
503 	    & PCI_CONF_CAP_MASK);
504 
505 	if (!value)
506 		return (0);
507 	/* get the offset of the first capability pointer from CAPPTR */
508 	nextcap = (off_t)(pci_config_get8(acc_handle, AGP_CONF_CAPPTR));
509 
510 	/* check AGP capability from the first capability pointer */
511 	while (nextcap) {
512 		ncapid = pci_config_get32(acc_handle, nextcap);
513 		if ((ncapid & PCI_CONF_CAPID_MASK)
514 		    == AGP_CAP_ID) /* find AGP cap */
515 			break;
516 
517 		nextcap = (off_t)((ncapid & PCI_CONF_NCAPID_MASK) >> 8);
518 	}
519 
520 	return (nextcap);
521 
522 }
523 
524 /*
525  * If i8xx device is successfully detected, 0 is returned.
526  * Otherwise -1 is returned.
527  */
528 static int
529 detect_i8xx_device(agp_master_softc_t *master_softc)
530 {
531 
532 	switch (master_softc->agpm_id) {
533 	case INTEL_IGD_810:
534 	case INTEL_IGD_810DC:
535 	case INTEL_IGD_810E:
536 	case INTEL_IGD_815:
537 		master_softc->agpm_dev_type = DEVICE_IS_I810;
538 		break;
539 	case INTEL_IGD_830M:
540 	case INTEL_IGD_845G:
541 	case INTEL_IGD_855GM:
542 	case INTEL_IGD_865G:
543 	case INTEL_IGD_915:
544 	case INTEL_IGD_915GM:
545 	case INTEL_IGD_945:
546 	case INTEL_IGD_945GM:
547 	case INTEL_IGD_946GZ:
548 	case INTEL_IGD_965G1:
549 	case INTEL_IGD_965G2:
550 	case INTEL_IGD_965GM:
551 	case INTEL_IGD_965Q:
552 		master_softc->agpm_dev_type = DEVICE_IS_I830;
553 		break;
554 	default:		/* unknown id */
555 		return (-1);
556 	}
557 
558 	return (0);
559 }
560 
561 /*
562  * If agp master is succssfully detected, 0 is returned.
563  * Otherwise -1 is returned.
564  */
565 static int
566 detect_agp_devcice(agp_master_softc_t *master_softc,
567     ddi_acc_handle_t acc_handle)
568 {
569 	off_t cap;
570 
571 	cap = agpmaster_cap_find(acc_handle);
572 	if (cap) {
573 		master_softc->agpm_dev_type = DEVICE_IS_AGP;
574 		master_softc->agpm_data.agpm_acaptr = cap;
575 		return (0);
576 	} else {
577 		return (-1);
578 	}
579 
580 }
581 
582 /*
583  * Please refer to GART and GTT entry format table in agpdefs.h for
584  * intel GTT entry format.
585  */
586 static int
587 phys2entry(uint32_t type, uint32_t physaddr, uint32_t *entry)
588 {
589 	uint32_t value;
590 
591 	switch (type) {
592 	case AGP_PHYSICAL:
593 	case AGP_NORMAL:
594 		value = (physaddr & GTT_PTE_MASK) | GTT_PTE_VALID;
595 		break;
596 	default:
597 		return (-1);
598 	}
599 
600 	*entry = value;
601 
602 	return (0);
603 }
604 
605 static int
606 i8xx_add_to_gtt(gtt_impl_t *gtt, igd_gtt_seg_t seg)
607 {
608 	int i;
609 	uint32_t *paddr;
610 	uint32_t entry;
611 	uint32_t maxpages;
612 
613 	maxpages = gtt->gtt_info.igd_apersize;
614 	maxpages = GTT_MB_TO_PAGES(maxpages);
615 
616 	paddr = seg.igs_phyaddr;
617 
618 	/* check if gtt max page number is reached */
619 	if ((seg.igs_pgstart + seg.igs_npage) > maxpages)
620 		return (-1);
621 
622 	paddr = seg.igs_phyaddr;
623 	for (i = seg.igs_pgstart; i < (seg.igs_pgstart + seg.igs_npage);
624 	    i++, paddr++) {
625 		if (phys2entry(seg.igs_type, *paddr, &entry))
626 			return (-1);
627 		ddi_put32(gtt->gtt_mmio_handle,
628 		    (uint32_t *)(gtt->gtt_addr + i * sizeof (uint32_t)),
629 		    entry);
630 	}
631 
632 	return (0);
633 }
634 
635 static void
636 i8xx_remove_from_gtt(gtt_impl_t *gtt, igd_gtt_seg_t seg)
637 {
638 	int i;
639 	uint32_t maxpages;
640 
641 	maxpages = gtt->gtt_info.igd_apersize;
642 	maxpages = GTT_MB_TO_PAGES(maxpages);
643 
644 	/* check if gtt max page number is reached */
645 	if ((seg.igs_pgstart + seg.igs_npage) > maxpages)
646 		return;
647 
648 	for (i = seg.igs_pgstart; i < (seg.igs_pgstart + seg.igs_npage); i++) {
649 		ddi_put32(gtt->gtt_mmio_handle,
650 		    (uint32_t *)(gtt->gtt_addr + i * sizeof (uint32_t)), 0);
651 	}
652 }
653