xref: /openbsd/sys/dev/pci/drm/amd/amdgpu/amdgpu_bios.c (revision f005ef32)
1 /*
2  * Copyright 2008 Advanced Micro Devices, Inc.
3  * Copyright 2008 Red Hat Inc.
4  * Copyright 2009 Jerome Glisse.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a
7  * copy of this software and associated documentation files (the "Software"),
8  * to deal in the Software without restriction, including without limitation
9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
10  * and/or sell copies of the Software, and to permit persons to whom the
11  * Software is furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
19  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
20  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
21  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
22  * OTHER DEALINGS IN THE SOFTWARE.
23  *
24  * Authors: Dave Airlie
25  *          Alex Deucher
26  *          Jerome Glisse
27  */
28 
29 #include "amdgpu.h"
30 #include "atom.h"
31 
32 #include <linux/device.h>
33 #include <linux/pci.h>
34 #include <linux/slab.h>
35 #include <linux/acpi.h>
36 
37 #if defined(__amd64__) || defined(__i386__)
38 #include <dev/isa/isareg.h>
39 #include <dev/isa/isavar.h>
40 #endif
41 
42 /*
43  * BIOS.
44  */
45 
46 #define AMD_VBIOS_SIGNATURE " 761295520"
47 #define AMD_VBIOS_SIGNATURE_OFFSET 0x30
48 #define AMD_VBIOS_SIGNATURE_SIZE sizeof(AMD_VBIOS_SIGNATURE)
49 #define AMD_VBIOS_SIGNATURE_END (AMD_VBIOS_SIGNATURE_OFFSET + AMD_VBIOS_SIGNATURE_SIZE)
50 #define AMD_IS_VALID_VBIOS(p) ((p)[0] == 0x55 && (p)[1] == 0xAA)
51 #define AMD_VBIOS_LENGTH(p) ((p)[2] << 9)
52 
53 /* Check if current bios is an ATOM BIOS.
54  * Return true if it is ATOM BIOS. Otherwise, return false.
55  */
check_atom_bios(uint8_t * bios,size_t size)56 static bool check_atom_bios(uint8_t *bios, size_t size)
57 {
58 	uint16_t tmp, bios_header_start;
59 
60 	if (!bios || size < 0x49) {
61 		DRM_INFO("vbios mem is null or mem size is wrong\n");
62 		return false;
63 	}
64 
65 	if (!AMD_IS_VALID_VBIOS(bios)) {
66 		DRM_INFO("BIOS signature incorrect %x %x\n", bios[0], bios[1]);
67 		return false;
68 	}
69 
70 	bios_header_start = bios[0x48] | (bios[0x49] << 8);
71 	if (!bios_header_start) {
72 		DRM_INFO("Can't locate bios header\n");
73 		return false;
74 	}
75 
76 	tmp = bios_header_start + 4;
77 	if (size < tmp) {
78 		DRM_INFO("BIOS header is broken\n");
79 		return false;
80 	}
81 
82 	if (!memcmp(bios + tmp, "ATOM", 4) ||
83 	    !memcmp(bios + tmp, "MOTA", 4)) {
84 		DRM_DEBUG("ATOMBIOS detected\n");
85 		return true;
86 	}
87 
88 	return false;
89 }
90 
91 /* If you boot an IGP board with a discrete card as the primary,
92  * the IGP rom is not accessible via the rom bar as the IGP rom is
93  * part of the system bios.  On boot, the system bios puts a
94  * copy of the igp rom at the start of vram if a discrete card is
95  * present.
96  */
97 #ifdef __linux__
igp_read_bios_from_vram(struct amdgpu_device * adev)98 static bool igp_read_bios_from_vram(struct amdgpu_device *adev)
99 {
100 	uint8_t __iomem *bios;
101 	resource_size_t vram_base;
102 	resource_size_t size = 256 * 1024; /* ??? */
103 
104 	if (!(adev->flags & AMD_IS_APU))
105 		if (amdgpu_device_need_post(adev))
106 			return false;
107 
108 	/* FB BAR not enabled */
109 	if (pci_resource_len(adev->pdev, 0) == 0)
110 		return false;
111 
112 	adev->bios = NULL;
113 	vram_base = pci_resource_start(adev->pdev, 0);
114 	bios = ioremap_wc(vram_base, size);
115 	if (!bios)
116 		return false;
117 
118 	adev->bios = kmalloc(size, GFP_KERNEL);
119 	if (!adev->bios) {
120 		iounmap(bios);
121 		return false;
122 	}
123 	adev->bios_size = size;
124 	memcpy_fromio(adev->bios, bios, size);
125 	iounmap(bios);
126 
127 	if (!check_atom_bios(adev->bios, size)) {
128 		kfree(adev->bios);
129 		return false;
130 	}
131 
132 	return true;
133 }
134 #else
igp_read_bios_from_vram(struct amdgpu_device * adev)135 static bool igp_read_bios_from_vram(struct amdgpu_device *adev)
136 {
137 	uint8_t __iomem *bios;
138 	resource_size_t size = 256 * 1024; /* ??? */
139 	bus_space_handle_t bsh;
140 	bus_space_tag_t bst = adev->memt;
141 
142 	if (!(adev->flags & AMD_IS_APU))
143 		if (amdgpu_device_need_post(adev))
144 			return false;
145 
146 	adev->bios = NULL;
147 
148 	if (bus_space_map(bst, adev->fb_aper_offset, size, BUS_SPACE_MAP_LINEAR, &bsh) != 0)
149 		return false;
150 
151 	bios = bus_space_vaddr(adev->memt, bsh);
152 	if (bios == NULL) {
153 		bus_space_unmap(bst, bsh, size);
154 		return false;
155 	}
156 
157 	adev->bios = kmalloc(size, GFP_KERNEL);
158 	if (!adev->bios) {
159 		bus_space_unmap(bst, bsh, size);
160 		return false;
161 	}
162 	adev->bios_size = size;
163 	memcpy_fromio(adev->bios, bios, size);
164 	bus_space_unmap(bst, bsh, size);
165 
166 	if (!check_atom_bios(adev->bios, size)) {
167 		kfree(adev->bios);
168 		return false;
169 	}
170 
171 	return true;
172 }
173 #endif
174 
175 #ifdef __linux__
amdgpu_read_bios(struct amdgpu_device * adev)176 bool amdgpu_read_bios(struct amdgpu_device *adev)
177 {
178 	uint8_t __iomem *bios;
179 	size_t size;
180 
181 	adev->bios = NULL;
182 	/* XXX: some cards may return 0 for rom size? ddx has a workaround */
183 	bios = pci_map_rom(adev->pdev, &size);
184 	if (!bios)
185 		return false;
186 
187 	adev->bios = kzalloc(size, GFP_KERNEL);
188 	if (adev->bios == NULL) {
189 		pci_unmap_rom(adev->pdev, bios);
190 		return false;
191 	}
192 	adev->bios_size = size;
193 	memcpy_fromio(adev->bios, bios, size);
194 	pci_unmap_rom(adev->pdev, bios);
195 
196 	if (!check_atom_bios(adev->bios, size)) {
197 		kfree(adev->bios);
198 		return false;
199 	}
200 
201 	return true;
202 }
203 #else
amdgpu_read_bios(struct amdgpu_device * adev)204 bool amdgpu_read_bios(struct amdgpu_device *adev)
205 {
206 	size_t size;
207 	pcireg_t address, mask;
208 	bus_space_handle_t romh;
209 	int rc;
210 
211 	adev->bios = NULL;
212 	/* XXX: some cards may return 0 for rom size? ddx has a workaround */
213 
214 	address = pci_conf_read(adev->pc, adev->pa_tag, PCI_ROM_REG);
215 	pci_conf_write(adev->pc, adev->pa_tag, PCI_ROM_REG, ~PCI_ROM_ENABLE);
216 	mask = pci_conf_read(adev->pc, adev->pa_tag, PCI_ROM_REG);
217 	address |= PCI_ROM_ENABLE;
218 	pci_conf_write(adev->pc, adev->pa_tag, PCI_ROM_REG, address);
219 
220 	size = PCI_ROM_SIZE(mask);
221 	if (size == 0)
222 		return false;
223 	rc = bus_space_map(adev->memt, PCI_ROM_ADDR(address), size, 0, &romh);
224 	if (rc != 0) {
225 		printf(": can't map PCI ROM (%d)\n", rc);
226 		return false;
227 	}
228 
229 	adev->bios = kzalloc(size, GFP_KERNEL);
230 	adev->bios_size = size;
231 	bus_space_read_region_1(adev->memt, romh, 0, adev->bios, size);
232 	bus_space_unmap(adev->memt, romh, size);
233 
234 	if (!check_atom_bios(adev->bios, size)) {
235 		kfree(adev->bios);
236 		return false;
237 	}
238 
239 	return true;
240 }
241 #endif
242 
amdgpu_read_bios_from_rom(struct amdgpu_device * adev)243 static bool amdgpu_read_bios_from_rom(struct amdgpu_device *adev)
244 {
245 	u8 header[AMD_VBIOS_SIGNATURE_END+1] = {0};
246 	int len;
247 
248 	if (!adev->asic_funcs || !adev->asic_funcs->read_bios_from_rom)
249 		return false;
250 
251 	/* validate VBIOS signature */
252 	if (amdgpu_asic_read_bios_from_rom(adev, &header[0], sizeof(header)) == false)
253 		return false;
254 	header[AMD_VBIOS_SIGNATURE_END] = 0;
255 
256 	if ((!AMD_IS_VALID_VBIOS(header)) ||
257 		memcmp((char *)&header[AMD_VBIOS_SIGNATURE_OFFSET],
258 		       AMD_VBIOS_SIGNATURE,
259 		       strlen(AMD_VBIOS_SIGNATURE)) != 0)
260 		return false;
261 
262 	/* valid vbios, go on */
263 	len = AMD_VBIOS_LENGTH(header);
264 	len = ALIGN(len, 4);
265 	adev->bios = kmalloc(len, GFP_KERNEL);
266 	if (!adev->bios) {
267 		DRM_ERROR("no memory to allocate for BIOS\n");
268 		return false;
269 	}
270 	adev->bios_size = len;
271 
272 	/* read complete BIOS */
273 	amdgpu_asic_read_bios_from_rom(adev, adev->bios, len);
274 
275 	if (!check_atom_bios(adev->bios, len)) {
276 		kfree(adev->bios);
277 		return false;
278 	}
279 
280 	return true;
281 }
282 
283 #ifdef __linux__
amdgpu_read_platform_bios(struct amdgpu_device * adev)284 static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)
285 {
286 	phys_addr_t rom = adev->pdev->rom;
287 	size_t romlen = adev->pdev->romlen;
288 	void __iomem *bios;
289 
290 	adev->bios = NULL;
291 
292 	if (!rom || romlen == 0)
293 		return false;
294 
295 	adev->bios = kzalloc(romlen, GFP_KERNEL);
296 	if (!adev->bios)
297 		return false;
298 
299 	bios = ioremap(rom, romlen);
300 	if (!bios)
301 		goto free_bios;
302 
303 	memcpy_fromio(adev->bios, bios, romlen);
304 	iounmap(bios);
305 
306 	if (!check_atom_bios(adev->bios, romlen))
307 		goto free_bios;
308 
309 	adev->bios_size = romlen;
310 
311 	return true;
312 free_bios:
313 	kfree(adev->bios);
314 	return false;
315 }
316 #else
amdgpu_read_platform_bios(struct amdgpu_device * adev)317 static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)
318 {
319 #if defined(__amd64__) || defined(__i386__)
320 	uint8_t __iomem *bios;
321 	bus_size_t size = 256 * 1024; /* ??? */
322 
323 	adev->bios = NULL;
324 
325 	bios = (u8 *)ISA_HOLE_VADDR(0xc0000);
326 
327 	adev->bios = kzalloc(size, GFP_KERNEL);
328 	if (adev->bios == NULL)
329 		return false;
330 
331 	memcpy_fromio(adev->bios, bios, size);
332 
333 	if (!check_atom_bios(adev->bios, size)) {
334 		kfree(adev->bios);
335 		return false;
336 	}
337 
338 	adev->bios_size = size;
339 
340 	return true;
341 #endif
342 	return false;
343 }
344 #endif
345 
346 #ifdef CONFIG_ACPI
347 /* ATRM is used to get the BIOS on the discrete cards in
348  * dual-gpu systems.
349  */
350 /* retrieve the ROM in 4k blocks */
351 #define ATRM_BIOS_PAGE 4096
352 /**
353  * amdgpu_atrm_call - fetch a chunk of the vbios
354  *
355  * @atrm_handle: acpi ATRM handle
356  * @bios: vbios image pointer
357  * @offset: offset of vbios image data to fetch
358  * @len: length of vbios image data to fetch
359  *
360  * Executes ATRM to fetch a chunk of the discrete
361  * vbios image on PX systems (all asics).
362  * Returns the length of the buffer fetched.
363  */
amdgpu_atrm_call(acpi_handle atrm_handle,uint8_t * bios,int offset,int len)364 static int amdgpu_atrm_call(acpi_handle atrm_handle, uint8_t *bios,
365 			    int offset, int len)
366 {
367 	acpi_status status;
368 	union acpi_object atrm_arg_elements[2], *obj;
369 	struct acpi_object_list atrm_arg;
370 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL};
371 
372 	atrm_arg.count = 2;
373 	atrm_arg.pointer = &atrm_arg_elements[0];
374 
375 	atrm_arg_elements[0].type = ACPI_TYPE_INTEGER;
376 	atrm_arg_elements[0].integer.value = offset;
377 
378 	atrm_arg_elements[1].type = ACPI_TYPE_INTEGER;
379 	atrm_arg_elements[1].integer.value = len;
380 
381 	status = acpi_evaluate_object(atrm_handle, NULL, &atrm_arg, &buffer);
382 	if (ACPI_FAILURE(status)) {
383 		DRM_ERROR("failed to evaluate ATRM got %s\n", acpi_format_exception(status));
384 		return -ENODEV;
385 	}
386 
387 	obj = (union acpi_object *)buffer.pointer;
388 	memcpy(bios+offset, obj->buffer.pointer, obj->buffer.length);
389 	len = obj->buffer.length;
390 	kfree(buffer.pointer);
391 	return len;
392 }
393 
amdgpu_atrm_get_bios(struct amdgpu_device * adev)394 static bool amdgpu_atrm_get_bios(struct amdgpu_device *adev)
395 {
396 	int ret;
397 	int size = 256 * 1024;
398 	int i;
399 	struct pci_dev *pdev = NULL;
400 	acpi_handle dhandle, atrm_handle;
401 	acpi_status status;
402 	bool found = false;
403 
404 	/* ATRM is for the discrete card only */
405 	if (adev->flags & AMD_IS_APU)
406 		return false;
407 
408 	/* ATRM is for on-platform devices only */
409 	if (dev_is_removable(&adev->pdev->dev))
410 		return false;
411 
412 #ifdef notyet
413 	while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_VGA << 8, pdev)) != NULL) {
414 		dhandle = ACPI_HANDLE(&pdev->dev);
415 		if (!dhandle)
416 			continue;
417 
418 		status = acpi_get_handle(dhandle, "ATRM", &atrm_handle);
419 		if (ACPI_SUCCESS(status)) {
420 			found = true;
421 			break;
422 		}
423 	}
424 
425 	if (!found) {
426 		while ((pdev = pci_get_class(PCI_CLASS_DISPLAY_OTHER << 8, pdev)) != NULL) {
427 			dhandle = ACPI_HANDLE(&pdev->dev);
428 			if (!dhandle)
429 				continue;
430 
431 			status = acpi_get_handle(dhandle, "ATRM", &atrm_handle);
432 			if (ACPI_SUCCESS(status)) {
433 				found = true;
434 				break;
435 			}
436 		}
437 	}
438 #else
439 	{
440 		pdev = adev->pdev;
441 		dhandle = ACPI_HANDLE(&pdev->dev);
442 
443 		if (dhandle) {
444 			status = acpi_get_handle(dhandle, "ATRM", &atrm_handle);
445 			if (ACPI_SUCCESS(status)) {
446 				found = true;
447 			}
448 		}
449 	}
450 #endif
451 
452 	if (!found)
453 		return false;
454 	pci_dev_put(pdev);
455 
456 	adev->bios = kmalloc(size, GFP_KERNEL);
457 	if (!adev->bios) {
458 		dev_err(adev->dev, "Unable to allocate bios\n");
459 		return false;
460 	}
461 
462 	for (i = 0; i < size / ATRM_BIOS_PAGE; i++) {
463 		ret = amdgpu_atrm_call(atrm_handle,
464 				       adev->bios,
465 				       (i * ATRM_BIOS_PAGE),
466 				       ATRM_BIOS_PAGE);
467 		if (ret < ATRM_BIOS_PAGE)
468 			break;
469 	}
470 
471 	if (!check_atom_bios(adev->bios, size)) {
472 		kfree(adev->bios);
473 		return false;
474 	}
475 	adev->bios_size = size;
476 	return true;
477 }
478 #else
amdgpu_atrm_get_bios(struct amdgpu_device * adev)479 static inline bool amdgpu_atrm_get_bios(struct amdgpu_device *adev)
480 {
481 	return false;
482 }
483 #endif
484 
amdgpu_read_disabled_bios(struct amdgpu_device * adev)485 static bool amdgpu_read_disabled_bios(struct amdgpu_device *adev)
486 {
487 	if (adev->flags & AMD_IS_APU)
488 		return igp_read_bios_from_vram(adev);
489 	else
490 		return (!adev->asic_funcs || !adev->asic_funcs->read_disabled_bios) ?
491 			false : amdgpu_asic_read_disabled_bios(adev);
492 }
493 
494 #ifdef CONFIG_ACPI
amdgpu_acpi_vfct_bios(struct amdgpu_device * adev)495 static bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
496 {
497 	struct acpi_table_header *hdr;
498 	acpi_size tbl_size;
499 	UEFI_ACPI_VFCT *vfct;
500 	unsigned int offset;
501 
502 	if (!ACPI_SUCCESS(acpi_get_table("VFCT", 1, &hdr)))
503 		return false;
504 	tbl_size = hdr->length;
505 	if (tbl_size < sizeof(UEFI_ACPI_VFCT)) {
506 		dev_info(adev->dev, "ACPI VFCT table present but broken (too short #1),skipping\n");
507 		return false;
508 	}
509 
510 	vfct = (UEFI_ACPI_VFCT *)hdr;
511 	offset = vfct->VBIOSImageOffset;
512 
513 	while (offset < tbl_size) {
514 		GOP_VBIOS_CONTENT *vbios = (GOP_VBIOS_CONTENT *)((char *)hdr + offset);
515 		VFCT_IMAGE_HEADER *vhdr = &vbios->VbiosHeader;
516 
517 		offset += sizeof(VFCT_IMAGE_HEADER);
518 		if (offset > tbl_size) {
519 			dev_info(adev->dev, "ACPI VFCT image header truncated,skipping\n");
520 			return false;
521 		}
522 
523 		offset += vhdr->ImageLength;
524 		if (offset > tbl_size) {
525 			dev_info(adev->dev, "ACPI VFCT image truncated,skipping\n");
526 			return false;
527 		}
528 
529 		if (vhdr->ImageLength &&
530 		    vhdr->PCIBus == adev->pdev->bus->number &&
531 		    vhdr->PCIDevice == PCI_SLOT(adev->pdev->devfn) &&
532 		    vhdr->PCIFunction == PCI_FUNC(adev->pdev->devfn) &&
533 		    vhdr->VendorID == adev->pdev->vendor &&
534 		    vhdr->DeviceID == adev->pdev->device) {
535 			adev->bios = kmemdup(&vbios->VbiosContent,
536 					     vhdr->ImageLength,
537 					     GFP_KERNEL);
538 
539 			if (!check_atom_bios(adev->bios, vhdr->ImageLength)) {
540 				kfree(adev->bios);
541 				return false;
542 			}
543 			adev->bios_size = vhdr->ImageLength;
544 			return true;
545 		}
546 	}
547 
548 	dev_info(adev->dev, "ACPI VFCT table present but broken (too short #2),skipping\n");
549 	return false;
550 }
551 #else
amdgpu_acpi_vfct_bios(struct amdgpu_device * adev)552 static inline bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
553 {
554 	return false;
555 }
556 #endif
557 
amdgpu_get_bios(struct amdgpu_device * adev)558 bool amdgpu_get_bios(struct amdgpu_device *adev)
559 {
560 	if (amdgpu_atrm_get_bios(adev)) {
561 		dev_info(adev->dev, "Fetched VBIOS from ATRM\n");
562 		goto success;
563 	}
564 
565 	if (amdgpu_acpi_vfct_bios(adev)) {
566 		dev_info(adev->dev, "Fetched VBIOS from VFCT\n");
567 		goto success;
568 	}
569 
570 	if (igp_read_bios_from_vram(adev)) {
571 		dev_info(adev->dev, "Fetched VBIOS from VRAM BAR\n");
572 		goto success;
573 	}
574 
575 	if (amdgpu_read_bios(adev)) {
576 		dev_info(adev->dev, "Fetched VBIOS from ROM BAR\n");
577 		goto success;
578 	}
579 
580 	if (amdgpu_read_bios_from_rom(adev)) {
581 		dev_info(adev->dev, "Fetched VBIOS from ROM\n");
582 		goto success;
583 	}
584 
585 	if (amdgpu_read_disabled_bios(adev)) {
586 		dev_info(adev->dev, "Fetched VBIOS from disabled ROM BAR\n");
587 		goto success;
588 	}
589 
590 	if (amdgpu_read_platform_bios(adev)) {
591 		dev_info(adev->dev, "Fetched VBIOS from platform\n");
592 		goto success;
593 	}
594 
595 	dev_err(adev->dev, "Unable to locate a BIOS ROM\n");
596 	return false;
597 
598 success:
599 	adev->is_atom_fw = adev->asic_type >= CHIP_VEGA10;
600 	return true;
601 }
602 
603 /* helper function for soc15 and onwards to read bios from rom */
amdgpu_soc15_read_bios_from_rom(struct amdgpu_device * adev,u8 * bios,u32 length_bytes)604 bool amdgpu_soc15_read_bios_from_rom(struct amdgpu_device *adev,
605 				     u8 *bios, u32 length_bytes)
606 {
607 	u32 *dw_ptr;
608 	u32 i, length_dw;
609 	u32 rom_offset;
610 	u32 rom_index_offset;
611 	u32 rom_data_offset;
612 
613 	if (bios == NULL)
614 		return false;
615 	if (length_bytes == 0)
616 		return false;
617 	/* APU vbios image is part of sbios image */
618 	if (adev->flags & AMD_IS_APU)
619 		return false;
620 	if (!adev->smuio.funcs ||
621 	    !adev->smuio.funcs->get_rom_index_offset ||
622 	    !adev->smuio.funcs->get_rom_data_offset)
623 		return false;
624 
625 	dw_ptr = (u32 *)bios;
626 	length_dw = ALIGN(length_bytes, 4) / 4;
627 
628 	rom_index_offset =
629 		adev->smuio.funcs->get_rom_index_offset(adev);
630 	rom_data_offset =
631 		adev->smuio.funcs->get_rom_data_offset(adev);
632 
633 	if (adev->nbio.funcs &&
634 	    adev->nbio.funcs->get_rom_offset) {
635 		rom_offset = adev->nbio.funcs->get_rom_offset(adev);
636 		rom_offset = rom_offset << 17;
637 	} else {
638 		rom_offset = 0;
639 	}
640 
641 	/* set rom index to rom_offset */
642 	WREG32(rom_index_offset, rom_offset);
643 	/* read out the rom data */
644 	for (i = 0; i < length_dw; i++)
645 		dw_ptr[i] = RREG32(rom_data_offset);
646 
647 	return true;
648 }
649