xref: /linux/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c (revision 5b0764a53235d3c77e1ed674e836e1b3fe1a4b1f)
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 #include <linux/vgaarb.h>
37 /*
38  * BIOS.
39  */
40 
41 #define AMD_VBIOS_SIGNATURE " 761295520"
42 #define AMD_VBIOS_SIGNATURE_OFFSET 0x30
43 #define AMD_VBIOS_SIGNATURE_SIZE sizeof(AMD_VBIOS_SIGNATURE)
44 #define AMD_VBIOS_SIGNATURE_END (AMD_VBIOS_SIGNATURE_OFFSET + AMD_VBIOS_SIGNATURE_SIZE)
45 #define AMD_IS_VALID_VBIOS(p) ((p)[0] == 0x55 && (p)[1] == 0xAA)
46 #define AMD_VBIOS_LENGTH(p) ((p)[2] << 9)
47 
48 /* Check if current bios is an ATOM BIOS.
49  * Return true if it is ATOM BIOS. Otherwise, return false.
50  */
51 static bool check_atom_bios(struct amdgpu_device *adev, size_t size)
52 {
53 	uint16_t tmp, bios_header_start;
54 	uint8_t *bios = adev->bios;
55 
56 	if (!bios || size < 0x49) {
57 		dev_dbg(adev->dev, "VBIOS mem is null or mem size is wrong\n");
58 		return false;
59 	}
60 
61 	if (!AMD_IS_VALID_VBIOS(bios)) {
62 		dev_dbg(adev->dev, "VBIOS signature incorrect %x %x\n", bios[0],
63 			bios[1]);
64 		return false;
65 	}
66 
67 	bios_header_start = bios[0x48] | (bios[0x49] << 8);
68 	if (!bios_header_start) {
69 		dev_dbg(adev->dev, "Can't locate VBIOS header\n");
70 		return false;
71 	}
72 
73 	tmp = bios_header_start + 4;
74 	if (size < tmp) {
75 		dev_dbg(adev->dev, "VBIOS header is broken\n");
76 		return false;
77 	}
78 
79 	if (!memcmp(bios + tmp, "ATOM", 4) ||
80 	    !memcmp(bios + tmp, "MOTA", 4)) {
81 		dev_dbg(adev->dev, "ATOMBIOS detected\n");
82 		return true;
83 	}
84 
85 	return false;
86 }
87 
88 void amdgpu_bios_release(struct amdgpu_device *adev)
89 {
90 	kfree(adev->bios);
91 	adev->bios = NULL;
92 	adev->bios_size = 0;
93 }
94 
95 /* If you boot an IGP board with a discrete card as the primary,
96  * the IGP rom is not accessible via the rom bar as the IGP rom is
97  * part of the system bios.  On boot, the system bios puts a
98  * copy of the igp rom at the start of vram if a discrete card is
99  * present.
100  * For SR-IOV, if dynamic critical region is not enabled,
101  * the vbios image is also put at the start of VRAM in the VF.
102  */
103 static bool amdgpu_read_bios_from_vram(struct amdgpu_device *adev)
104 {
105 	uint8_t __iomem *bios = NULL;
106 	resource_size_t vram_base;
107 	u32 size = 256U * 1024U; /* ??? */
108 
109 	if (!(adev->flags & AMD_IS_APU))
110 		if (amdgpu_device_need_post(adev))
111 			return false;
112 
113 	/* FB BAR not enabled */
114 	if (pci_resource_len(adev->pdev, 0) == 0)
115 		return false;
116 
117 	adev->bios = NULL;
118 	vram_base = pci_resource_start(adev->pdev, 0);
119 
120 	adev->bios = kmalloc(size, GFP_KERNEL);
121 	if (!adev->bios)
122 		return false;
123 
124 	/* For SRIOV with dynamic critical region is enabled,
125 	 * the vbios image is put at a dynamic offset of VRAM in the VF.
126 	 * If dynamic critical region is disabled, follow the existing logic as on baremetal.
127 	 */
128 	if (amdgpu_sriov_vf(adev) && adev->virt.is_dynamic_crit_regn_enabled) {
129 		if (amdgpu_virt_get_dynamic_data_info(adev,
130 				AMD_SRIOV_MSG_VBIOS_IMG_TABLE_ID, adev->bios, &size)) {
131 			amdgpu_bios_release(adev);
132 			return false;
133 		}
134 	} else {
135 		bios = ioremap_wc(vram_base, size);
136 		if (!bios) {
137 			amdgpu_bios_release(adev);
138 			return false;
139 		}
140 
141 		memcpy_fromio(adev->bios, bios, size);
142 		iounmap(bios);
143 	}
144 
145 	adev->bios_size = size;
146 
147 	if (!check_atom_bios(adev, size)) {
148 		amdgpu_bios_release(adev);
149 		return false;
150 	}
151 
152 	return true;
153 }
154 
155 static bool amdgpu_read_bios_from_spm(struct amdgpu_device *adev)
156 {
157 	u64 spm_base, spm_size;
158 	void *bios = NULL;
159 	u32 size = 256U * 1024U; /* ??? */
160 	int r;
161 
162 	if (!amdgpu_virt_vram_is_spm(adev))
163 		return false;
164 
165 	r = amdgpu_acpi_find_gpu_memory_in_srat(adev, &spm_base, &spm_size);
166 	if (r)
167 		return false;
168 
169 	adev->bios = kmalloc(size, GFP_KERNEL);
170 	if (!adev->bios)
171 		return false;
172 
173 	/* For SRIOV with dynamic critical region is enabled,
174 	 * the vbios image is put at a dynamic offset of VRAM in the VF.
175 	 * If dynamic critical region is disabled, read it from SPM.
176 	 */
177 	if (amdgpu_sriov_vf(adev) && adev->virt.is_dynamic_crit_regn_enabled) {
178 		if (amdgpu_virt_get_dynamic_data_info(adev,
179 						      AMD_SRIOV_MSG_VBIOS_IMG_TABLE_ID,
180 						      adev->bios, &size)) {
181 			amdgpu_bios_release(adev);
182 			return false;
183 		}
184 	} else {
185 		bios = memremap(spm_base, size, MEMREMAP_WB);
186 		if (!bios) {
187 			amdgpu_bios_release(adev);
188 			return false;
189 		}
190 
191 		memcpy(adev->bios, bios, size);
192 		memunmap(bios);
193 	}
194 
195 	adev->bios_size = size;
196 
197 	if (!check_atom_bios(adev, size)) {
198 		amdgpu_bios_release(adev);
199 		return false;
200 	}
201 
202 	return true;
203 }
204 
205 bool amdgpu_read_bios(struct amdgpu_device *adev)
206 {
207 	uint8_t __iomem *bios;
208 	size_t size;
209 
210 	adev->bios = NULL;
211 	/* XXX: some cards may return 0 for rom size? ddx has a workaround */
212 	bios = pci_map_rom(adev->pdev, &size);
213 	if (!bios)
214 		return false;
215 
216 	adev->bios = kzalloc(size, GFP_KERNEL);
217 	if (adev->bios == NULL) {
218 		pci_unmap_rom(adev->pdev, bios);
219 		return false;
220 	}
221 	adev->bios_size = size;
222 	memcpy_fromio(adev->bios, bios, size);
223 	pci_unmap_rom(adev->pdev, bios);
224 
225 	if (!check_atom_bios(adev, size)) {
226 		amdgpu_bios_release(adev);
227 		return false;
228 	}
229 
230 	return true;
231 }
232 
233 static bool amdgpu_read_bios_from_rom(struct amdgpu_device *adev)
234 {
235 	u8 header[AMD_VBIOS_SIGNATURE_END+1] = {0};
236 	int len;
237 
238 	if (!adev->asic_funcs || !adev->asic_funcs->read_bios_from_rom)
239 		return false;
240 
241 	/* validate VBIOS signature */
242 	if (amdgpu_asic_read_bios_from_rom(adev, &header[0], sizeof(header)) == false)
243 		return false;
244 	header[AMD_VBIOS_SIGNATURE_END] = 0;
245 
246 	if ((!AMD_IS_VALID_VBIOS(header)) ||
247 		memcmp((char *)&header[AMD_VBIOS_SIGNATURE_OFFSET],
248 		       AMD_VBIOS_SIGNATURE,
249 		       strlen(AMD_VBIOS_SIGNATURE)) != 0)
250 		return false;
251 
252 	/* valid vbios, go on */
253 	len = AMD_VBIOS_LENGTH(header);
254 	len = ALIGN(len, 4);
255 	adev->bios = kmalloc(len, GFP_KERNEL);
256 	if (!adev->bios) {
257 		DRM_ERROR("no memory to allocate for BIOS\n");
258 		return false;
259 	}
260 	adev->bios_size = len;
261 
262 	/* read complete BIOS */
263 	amdgpu_asic_read_bios_from_rom(adev, adev->bios, len);
264 
265 	if (!check_atom_bios(adev, len)) {
266 		amdgpu_bios_release(adev);
267 		return false;
268 	}
269 
270 	return true;
271 }
272 
273 static bool amdgpu_read_platform_bios(struct amdgpu_device *adev)
274 {
275 	phys_addr_t rom = adev->pdev->rom;
276 	size_t romlen = adev->pdev->romlen;
277 	void __iomem *bios;
278 
279 	adev->bios = NULL;
280 
281 	if (!rom || romlen == 0)
282 		return false;
283 
284 	adev->bios = kzalloc(romlen, GFP_KERNEL);
285 	if (!adev->bios)
286 		return false;
287 
288 	bios = ioremap(rom, romlen);
289 	if (!bios)
290 		goto free_bios;
291 
292 	memcpy_fromio(adev->bios, bios, romlen);
293 	iounmap(bios);
294 
295 	if (!check_atom_bios(adev, romlen))
296 		goto free_bios;
297 
298 	adev->bios_size = romlen;
299 
300 	return true;
301 free_bios:
302 	amdgpu_bios_release(adev);
303 
304 	return false;
305 }
306 
307 #ifdef CONFIG_ACPI
308 /* ATRM is used to get the BIOS on the discrete cards in
309  * dual-gpu systems.
310  */
311 /* retrieve the ROM in 4k blocks */
312 #define ATRM_BIOS_PAGE 4096
313 /**
314  * amdgpu_atrm_call - fetch a chunk of the vbios
315  *
316  * @atrm_handle: acpi ATRM handle
317  * @bios: vbios image pointer
318  * @offset: offset of vbios image data to fetch
319  * @len: length of vbios image data to fetch
320  *
321  * Executes ATRM to fetch a chunk of the discrete
322  * vbios image on PX systems (all asics).
323  * Returns the length of the buffer fetched.
324  */
325 static int amdgpu_atrm_call(acpi_handle atrm_handle, uint8_t *bios,
326 			    int offset, int len)
327 {
328 	acpi_status status;
329 	union acpi_object atrm_arg_elements[2], *obj;
330 	struct acpi_object_list atrm_arg;
331 	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL};
332 
333 	atrm_arg.count = 2;
334 	atrm_arg.pointer = &atrm_arg_elements[0];
335 
336 	atrm_arg_elements[0].type = ACPI_TYPE_INTEGER;
337 	atrm_arg_elements[0].integer.value = offset;
338 
339 	atrm_arg_elements[1].type = ACPI_TYPE_INTEGER;
340 	atrm_arg_elements[1].integer.value = len;
341 
342 	status = acpi_evaluate_object(atrm_handle, NULL, &atrm_arg, &buffer);
343 	if (ACPI_FAILURE(status)) {
344 		DRM_ERROR("failed to evaluate ATRM got %s\n", acpi_format_exception(status));
345 		return -ENODEV;
346 	}
347 
348 	obj = (union acpi_object *)buffer.pointer;
349 	if (!obj || obj->type != ACPI_TYPE_BUFFER) {
350 		DRM_ERROR("ATRM returned an invalid object\n");
351 		kfree(buffer.pointer);
352 		return -EINVAL;
353 	}
354 
355 	len = min_t(size_t, obj->buffer.length, len);
356 	memcpy(bios+offset, obj->buffer.pointer, len);
357 	kfree(buffer.pointer);
358 	return len;
359 }
360 
361 static bool amdgpu_atrm_get_bios(struct amdgpu_device *adev)
362 {
363 	int ret;
364 	int size = 256 * 1024;
365 	int i;
366 	struct pci_dev *pdev = NULL;
367 	acpi_handle dhandle, atrm_handle;
368 	acpi_status status;
369 	bool found = false;
370 
371 	/* ATRM is for on-platform devices only */
372 	if (dev_is_removable(&adev->pdev->dev))
373 		return false;
374 
375 	while ((pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev))) {
376 		if ((pdev->class != PCI_CLASS_DISPLAY_VGA << 8) &&
377 		    (pdev->class != PCI_CLASS_DISPLAY_OTHER << 8))
378 			continue;
379 
380 		dhandle = ACPI_HANDLE(&pdev->dev);
381 		if (!dhandle)
382 			continue;
383 
384 		status = acpi_get_handle(dhandle, "ATRM", &atrm_handle);
385 		if (ACPI_SUCCESS(status)) {
386 			found = true;
387 			break;
388 		}
389 	}
390 
391 	if (!found)
392 		return false;
393 	pci_dev_put(pdev);
394 
395 	adev->bios = kmalloc(size, GFP_KERNEL);
396 	if (!adev->bios) {
397 		dev_err(adev->dev, "Unable to allocate bios\n");
398 		return false;
399 	}
400 
401 	for (i = 0; i < size / ATRM_BIOS_PAGE; i++) {
402 		ret = amdgpu_atrm_call(atrm_handle,
403 				       adev->bios,
404 				       (i * ATRM_BIOS_PAGE),
405 				       ATRM_BIOS_PAGE);
406 		if (ret < ATRM_BIOS_PAGE)
407 			break;
408 	}
409 
410 	if (!check_atom_bios(adev, size)) {
411 		amdgpu_bios_release(adev);
412 		return false;
413 	}
414 	adev->bios_size = size;
415 	return true;
416 }
417 #else
418 static inline bool amdgpu_atrm_get_bios(struct amdgpu_device *adev)
419 {
420 	return false;
421 }
422 #endif
423 
424 static bool amdgpu_read_disabled_bios(struct amdgpu_device *adev)
425 {
426 	return (!adev->asic_funcs || !adev->asic_funcs->read_disabled_bios) ?
427 		false : amdgpu_asic_read_disabled_bios(adev);
428 }
429 
430 #ifdef CONFIG_ACPI
431 /**
432  * amdgpu_acpi_vfct_match() - Check if a VFCT entry matches the device
433  * @adev: AMDGPU device
434  * @vhdr: VFCT image header to check
435  *
436  * VFCT entries contain the PCI bus number as recorded during BIOS POST.
437  * On systems where the kernel renumbers PCI buses (e.g. pci=realloc or
438  * resource conflicts), the runtime bus number may differ from the POST
439  * value.  Match by device identity (vendor + device + function) and use
440  * the bus number as a preference: exact bus match is preferred, but when
441  * the bus numbers disagree we accept the entry if the device identity
442  * matches.
443  *
444  * Returns: 0 on match, -ENODEV on no match
445  */
446 static int amdgpu_acpi_vfct_match(struct amdgpu_device *adev,
447 				  VFCT_IMAGE_HEADER *vhdr)
448 {
449 	/* Vendor and device IDs must always match */
450 	if (vhdr->VendorID != adev->pdev->vendor ||
451 	    vhdr->DeviceID != adev->pdev->device)
452 		return -ENODEV;
453 
454 	if (vhdr->PCIDevice != PCI_SLOT(adev->pdev->devfn) ||
455 	    vhdr->PCIFunction != PCI_FUNC(adev->pdev->devfn))
456 		return -ENODEV;
457 
458 	/* Exact bus number match - preferred */
459 	if (vhdr->PCIBus == adev->pdev->bus->number)
460 		return 0;
461 
462 	/* Bus mismatch but device identity matches (PCI renumbering case) */
463 	dev_notice(adev->dev,
464 		   "VFCT bus number mismatch: table %u != runtime %u, matching by device identity (vendor 0x%04x device 0x%04x)\n",
465 		   vhdr->PCIBus, adev->pdev->bus->number,
466 		   adev->pdev->vendor, adev->pdev->device);
467 	return 0;
468 }
469 
470 static bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
471 {
472 	struct acpi_table_header *hdr;
473 	acpi_size tbl_size;
474 	UEFI_ACPI_VFCT *vfct;
475 	unsigned int offset;
476 	bool r = false;
477 
478 	if (!ACPI_SUCCESS(acpi_get_table("VFCT", 1, &hdr)))
479 		return false;
480 	tbl_size = hdr->length;
481 	if (tbl_size < sizeof(UEFI_ACPI_VFCT)) {
482 		dev_info(adev->dev, "ACPI VFCT table present but broken (too short #1),skipping\n");
483 		goto out;
484 	}
485 
486 	vfct = (UEFI_ACPI_VFCT *)hdr;
487 	offset = vfct->VBIOSImageOffset;
488 
489 	while (offset < tbl_size) {
490 		GOP_VBIOS_CONTENT *vbios = (GOP_VBIOS_CONTENT *)((char *)hdr + offset);
491 		VFCT_IMAGE_HEADER *vhdr = &vbios->VbiosHeader;
492 
493 		offset += sizeof(VFCT_IMAGE_HEADER);
494 		if (offset > tbl_size) {
495 			dev_info(adev->dev, "ACPI VFCT image header truncated,skipping\n");
496 			goto out;
497 		}
498 
499 		offset += vhdr->ImageLength;
500 		if (offset > tbl_size) {
501 			dev_info(adev->dev, "ACPI VFCT image truncated,skipping\n");
502 			goto out;
503 		}
504 
505 		if (vhdr->ImageLength &&
506 		    !amdgpu_acpi_vfct_match(adev, vhdr)) {
507 			adev->bios = kmemdup(&vbios->VbiosContent,
508 					     vhdr->ImageLength,
509 					     GFP_KERNEL);
510 
511 			if (!check_atom_bios(adev, vhdr->ImageLength)) {
512 				amdgpu_bios_release(adev);
513 				goto out;
514 			}
515 			adev->bios_size = vhdr->ImageLength;
516 			r = true;
517 			goto out;
518 		}
519 	}
520 
521 	dev_info(adev->dev, "ACPI VFCT table present but broken (too short #2),skipping\n");
522 
523 out:
524 	acpi_put_table(hdr);
525 	return r;
526 }
527 #else
528 static inline bool amdgpu_acpi_vfct_bios(struct amdgpu_device *adev)
529 {
530 	return false;
531 }
532 #endif
533 
534 static bool amdgpu_get_bios_apu(struct amdgpu_device *adev)
535 {
536 	if (amdgpu_acpi_vfct_bios(adev)) {
537 		dev_info(adev->dev, "Fetched VBIOS from VFCT\n");
538 		goto success;
539 	}
540 
541 	if (amdgpu_read_bios_from_vram(adev)) {
542 		dev_info(adev->dev, "Fetched VBIOS from VRAM BAR\n");
543 		goto success;
544 	}
545 
546 	if (amdgpu_read_bios(adev)) {
547 		dev_info(adev->dev, "Fetched VBIOS from ROM BAR\n");
548 		goto success;
549 	}
550 
551 	if (amdgpu_read_platform_bios(adev)) {
552 		dev_info(adev->dev, "Fetched VBIOS from platform\n");
553 		goto success;
554 	}
555 
556 	dev_err(adev->dev, "Unable to locate a BIOS ROM\n");
557 	return false;
558 
559 success:
560 	return true;
561 }
562 
563 static bool amdgpu_prefer_rom_resource(struct amdgpu_device *adev)
564 {
565 	struct resource *res = &adev->pdev->resource[PCI_ROM_RESOURCE];
566 
567 	return (res->flags & IORESOURCE_ROM_SHADOW) ||
568 	       adev->pdev == vga_default_device();
569 }
570 
571 static bool amdgpu_get_bios_dgpu(struct amdgpu_device *adev)
572 {
573 	if (amdgpu_atrm_get_bios(adev)) {
574 		dev_info(adev->dev, "Fetched VBIOS from ATRM\n");
575 		goto success;
576 	}
577 
578 	if (amdgpu_acpi_vfct_bios(adev)) {
579 		dev_info(adev->dev, "Fetched VBIOS from VFCT\n");
580 		goto success;
581 	}
582 
583 	if (amdgpu_read_bios_from_spm(adev)) {
584 		dev_info(adev->dev, "Fetched VBIOS from SPM\n");
585 		goto success;
586 	}
587 
588 	/* this is required for SR-IOV */
589 	if (amdgpu_read_bios_from_vram(adev)) {
590 		dev_info(adev->dev, "Fetched VBIOS from VRAM BAR\n");
591 		goto success;
592 	}
593 
594 	if (amdgpu_prefer_rom_resource(adev)) {
595 		if (amdgpu_read_bios(adev)) {
596 			dev_info(adev->dev, "Fetched VBIOS from ROM BAR\n");
597 			goto success;
598 		}
599 
600 		if (amdgpu_read_platform_bios(adev)) {
601 			dev_info(adev->dev, "Fetched VBIOS from platform\n");
602 			goto success;
603 		}
604 
605 	} else {
606 		if (amdgpu_read_platform_bios(adev)) {
607 			dev_info(adev->dev, "Fetched VBIOS from platform\n");
608 			goto success;
609 		}
610 
611 		if (amdgpu_read_bios(adev)) {
612 			dev_info(adev->dev, "Fetched VBIOS from ROM BAR\n");
613 			goto success;
614 		}
615 	}
616 
617 	if (amdgpu_read_bios_from_rom(adev)) {
618 		dev_info(adev->dev, "Fetched VBIOS from ROM\n");
619 		goto success;
620 	}
621 
622 	if (amdgpu_read_disabled_bios(adev)) {
623 		dev_info(adev->dev, "Fetched VBIOS from disabled ROM BAR\n");
624 		goto success;
625 	}
626 
627 	dev_err(adev->dev, "Unable to locate a BIOS ROM\n");
628 	return false;
629 
630 success:
631 	return true;
632 }
633 
634 bool amdgpu_get_bios(struct amdgpu_device *adev)
635 {
636 	bool found;
637 
638 	if (adev->flags & AMD_IS_APU)
639 		found = amdgpu_get_bios_apu(adev);
640 	else
641 		found = amdgpu_get_bios_dgpu(adev);
642 
643 	if (found)
644 		adev->is_atom_fw = adev->asic_type >= CHIP_VEGA10;
645 
646 	return found;
647 }
648 
649 /* helper function for soc15 and onwards to read bios from rom */
650 bool amdgpu_soc15_read_bios_from_rom(struct amdgpu_device *adev,
651 				     u8 *bios, u32 length_bytes)
652 {
653 	u32 *dw_ptr;
654 	u32 i, length_dw;
655 	u32 rom_offset;
656 	u32 rom_index_offset;
657 	u32 rom_data_offset;
658 
659 	if (bios == NULL)
660 		return false;
661 	if (length_bytes == 0)
662 		return false;
663 	/* APU vbios image is part of sbios image */
664 	if (adev->flags & AMD_IS_APU)
665 		return false;
666 	if (!adev->smuio.funcs ||
667 	    !adev->smuio.funcs->get_rom_index_offset ||
668 	    !adev->smuio.funcs->get_rom_data_offset)
669 		return false;
670 
671 	dw_ptr = (u32 *)bios;
672 	length_dw = ALIGN(length_bytes, 4) / 4;
673 
674 	rom_index_offset =
675 		adev->smuio.funcs->get_rom_index_offset(adev);
676 	rom_data_offset =
677 		adev->smuio.funcs->get_rom_data_offset(adev);
678 
679 	if (adev->nbio.funcs &&
680 	    adev->nbio.funcs->get_rom_offset) {
681 		rom_offset = adev->nbio.funcs->get_rom_offset(adev);
682 		rom_offset = rom_offset << 17;
683 	} else {
684 		rom_offset = 0;
685 	}
686 
687 	/* set rom index to rom_offset */
688 	WREG32(rom_index_offset, rom_offset);
689 	/* read out the rom data */
690 	for (i = 0; i < length_dw; i++)
691 		dw_ptr[i] = RREG32(rom_data_offset);
692 
693 	return true;
694 }
695