xref: /openbmc/linux/arch/x86/kernel/early-quirks.c (revision 275876e2)
1 /* Various workarounds for chipset bugs.
2    This code runs very early and can't use the regular PCI subsystem
3    The entries are keyed to PCI bridges which usually identify chipsets
4    uniquely.
5    This is only for whole classes of chipsets with specific problems which
6    need early invasive action (e.g. before the timers are initialized).
7    Most PCI device specific workarounds can be done later and should be
8    in standard PCI quirks
9    Mainboard specific bugs should be handled by DMI entries.
10    CPU specific bugs in setup.c */
11 
12 #include <linux/pci.h>
13 #include <linux/acpi.h>
14 #include <linux/pci_ids.h>
15 #include <drm/i915_drm.h>
16 #include <asm/pci-direct.h>
17 #include <asm/dma.h>
18 #include <asm/io_apic.h>
19 #include <asm/apic.h>
20 #include <asm/hpet.h>
21 #include <asm/iommu.h>
22 #include <asm/gart.h>
23 #include <asm/irq_remapping.h>
24 
25 static void __init fix_hypertransport_config(int num, int slot, int func)
26 {
27 	u32 htcfg;
28 	/*
29 	 * we found a hypertransport bus
30 	 * make sure that we are broadcasting
31 	 * interrupts to all cpus on the ht bus
32 	 * if we're using extended apic ids
33 	 */
34 	htcfg = read_pci_config(num, slot, func, 0x68);
35 	if (htcfg & (1 << 18)) {
36 		printk(KERN_INFO "Detected use of extended apic ids "
37 				 "on hypertransport bus\n");
38 		if ((htcfg & (1 << 17)) == 0) {
39 			printk(KERN_INFO "Enabling hypertransport extended "
40 					 "apic interrupt broadcast\n");
41 			printk(KERN_INFO "Note this is a bios bug, "
42 					 "please contact your hw vendor\n");
43 			htcfg |= (1 << 17);
44 			write_pci_config(num, slot, func, 0x68, htcfg);
45 		}
46 	}
47 
48 
49 }
50 
51 static void __init via_bugs(int  num, int slot, int func)
52 {
53 #ifdef CONFIG_GART_IOMMU
54 	if ((max_pfn > MAX_DMA32_PFN ||  force_iommu) &&
55 	    !gart_iommu_aperture_allowed) {
56 		printk(KERN_INFO
57 		       "Looks like a VIA chipset. Disabling IOMMU."
58 		       " Override with iommu=allowed\n");
59 		gart_iommu_aperture_disabled = 1;
60 	}
61 #endif
62 }
63 
64 #ifdef CONFIG_ACPI
65 #ifdef CONFIG_X86_IO_APIC
66 
67 static int __init nvidia_hpet_check(struct acpi_table_header *header)
68 {
69 	return 0;
70 }
71 #endif /* CONFIG_X86_IO_APIC */
72 #endif /* CONFIG_ACPI */
73 
74 static void __init nvidia_bugs(int num, int slot, int func)
75 {
76 #ifdef CONFIG_ACPI
77 #ifdef CONFIG_X86_IO_APIC
78 	/*
79 	 * All timer overrides on Nvidia are
80 	 * wrong unless HPET is enabled.
81 	 * Unfortunately that's not true on many Asus boards.
82 	 * We don't know yet how to detect this automatically, but
83 	 * at least allow a command line override.
84 	 */
85 	if (acpi_use_timer_override)
86 		return;
87 
88 	if (acpi_table_parse(ACPI_SIG_HPET, nvidia_hpet_check)) {
89 		acpi_skip_timer_override = 1;
90 		printk(KERN_INFO "Nvidia board "
91 		       "detected. Ignoring ACPI "
92 		       "timer override.\n");
93 		printk(KERN_INFO "If you got timer trouble "
94 			"try acpi_use_timer_override\n");
95 	}
96 #endif
97 #endif
98 	/* RED-PEN skip them on mptables too? */
99 
100 }
101 
102 #if defined(CONFIG_ACPI) && defined(CONFIG_X86_IO_APIC)
103 static u32 __init ati_ixp4x0_rev(int num, int slot, int func)
104 {
105 	u32 d;
106 	u8  b;
107 
108 	b = read_pci_config_byte(num, slot, func, 0xac);
109 	b &= ~(1<<5);
110 	write_pci_config_byte(num, slot, func, 0xac, b);
111 
112 	d = read_pci_config(num, slot, func, 0x70);
113 	d |= 1<<8;
114 	write_pci_config(num, slot, func, 0x70, d);
115 
116 	d = read_pci_config(num, slot, func, 0x8);
117 	d &= 0xff;
118 	return d;
119 }
120 
121 static void __init ati_bugs(int num, int slot, int func)
122 {
123 	u32 d;
124 	u8  b;
125 
126 	if (acpi_use_timer_override)
127 		return;
128 
129 	d = ati_ixp4x0_rev(num, slot, func);
130 	if (d  < 0x82)
131 		acpi_skip_timer_override = 1;
132 	else {
133 		/* check for IRQ0 interrupt swap */
134 		outb(0x72, 0xcd6); b = inb(0xcd7);
135 		if (!(b & 0x2))
136 			acpi_skip_timer_override = 1;
137 	}
138 
139 	if (acpi_skip_timer_override) {
140 		printk(KERN_INFO "SB4X0 revision 0x%x\n", d);
141 		printk(KERN_INFO "Ignoring ACPI timer override.\n");
142 		printk(KERN_INFO "If you got timer trouble "
143 		       "try acpi_use_timer_override\n");
144 	}
145 }
146 
147 static u32 __init ati_sbx00_rev(int num, int slot, int func)
148 {
149 	u32 d;
150 
151 	d = read_pci_config(num, slot, func, 0x8);
152 	d &= 0xff;
153 
154 	return d;
155 }
156 
157 static void __init ati_bugs_contd(int num, int slot, int func)
158 {
159 	u32 d, rev;
160 
161 	rev = ati_sbx00_rev(num, slot, func);
162 	if (rev >= 0x40)
163 		acpi_fix_pin2_polarity = 1;
164 
165 	/*
166 	 * SB600: revisions 0x11, 0x12, 0x13, 0x14, ...
167 	 * SB700: revisions 0x39, 0x3a, ...
168 	 * SB800: revisions 0x40, 0x41, ...
169 	 */
170 	if (rev >= 0x39)
171 		return;
172 
173 	if (acpi_use_timer_override)
174 		return;
175 
176 	/* check for IRQ0 interrupt swap */
177 	d = read_pci_config(num, slot, func, 0x64);
178 	if (!(d & (1<<14)))
179 		acpi_skip_timer_override = 1;
180 
181 	if (acpi_skip_timer_override) {
182 		printk(KERN_INFO "SB600 revision 0x%x\n", rev);
183 		printk(KERN_INFO "Ignoring ACPI timer override.\n");
184 		printk(KERN_INFO "If you got timer trouble "
185 		       "try acpi_use_timer_override\n");
186 	}
187 }
188 #else
189 static void __init ati_bugs(int num, int slot, int func)
190 {
191 }
192 
193 static void __init ati_bugs_contd(int num, int slot, int func)
194 {
195 }
196 #endif
197 
198 static void __init intel_remapping_check(int num, int slot, int func)
199 {
200 	u8 revision;
201 	u16 device;
202 
203 	device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID);
204 	revision = read_pci_config_byte(num, slot, func, PCI_REVISION_ID);
205 
206 	/*
207 	 * Revision <= 13 of all triggering devices id in this quirk
208 	 * have a problem draining interrupts when irq remapping is
209 	 * enabled, and should be flagged as broken. Additionally
210 	 * revision 0x22 of device id 0x3405 has this problem.
211 	 */
212 	if (revision <= 0x13)
213 		set_irq_remapping_broken();
214 	else if (device == 0x3405 && revision == 0x22)
215 		set_irq_remapping_broken();
216 }
217 
218 /*
219  * Systems with Intel graphics controllers set aside memory exclusively
220  * for gfx driver use.  This memory is not marked in the E820 as reserved
221  * or as RAM, and so is subject to overlap from E820 manipulation later
222  * in the boot process.  On some systems, MMIO space is allocated on top,
223  * despite the efforts of the "RAM buffer" approach, which simply rounds
224  * memory boundaries up to 64M to try to catch space that may decode
225  * as RAM and so is not suitable for MMIO.
226  *
227  * And yes, so far on current devices the base addr is always under 4G.
228  */
229 static u32 __init intel_stolen_base(int num, int slot, int func, size_t stolen_size)
230 {
231 	u32 base;
232 
233 	/*
234 	 * For the PCI IDs in this quirk, the stolen base is always
235 	 * in 0x5c, aka the BDSM register (yes that's really what
236 	 * it's called).
237 	 */
238 	base = read_pci_config(num, slot, func, 0x5c);
239 	base &= ~((1<<20) - 1);
240 
241 	return base;
242 }
243 
244 #define KB(x)	((x) * 1024UL)
245 #define MB(x)	(KB (KB (x)))
246 #define GB(x)	(MB (KB (x)))
247 
248 static size_t __init i830_tseg_size(void)
249 {
250 	u8 tmp = read_pci_config_byte(0, 0, 0, I830_ESMRAMC);
251 
252 	if (!(tmp & TSEG_ENABLE))
253 		return 0;
254 
255 	if (tmp & I830_TSEG_SIZE_1M)
256 		return MB(1);
257 	else
258 		return KB(512);
259 }
260 
261 static size_t __init i845_tseg_size(void)
262 {
263 	u8 tmp = read_pci_config_byte(0, 0, 0, I845_ESMRAMC);
264 
265 	if (!(tmp & TSEG_ENABLE))
266 		return 0;
267 
268 	switch (tmp & I845_TSEG_SIZE_MASK) {
269 	case I845_TSEG_SIZE_512K:
270 		return KB(512);
271 	case I845_TSEG_SIZE_1M:
272 		return MB(1);
273 	default:
274 		WARN_ON(1);
275 		return 0;
276 	}
277 }
278 
279 static size_t __init i85x_tseg_size(void)
280 {
281 	u8 tmp = read_pci_config_byte(0, 0, 0, I85X_ESMRAMC);
282 
283 	if (!(tmp & TSEG_ENABLE))
284 		return 0;
285 
286 	return MB(1);
287 }
288 
289 static size_t __init i830_mem_size(void)
290 {
291 	return read_pci_config_byte(0, 0, 0, I830_DRB3) * MB(32);
292 }
293 
294 static size_t __init i85x_mem_size(void)
295 {
296 	return read_pci_config_byte(0, 0, 1, I85X_DRB3) * MB(32);
297 }
298 
299 /*
300  * On 830/845/85x the stolen memory base isn't available in any
301  * register. We need to calculate it as TOM-TSEG_SIZE-stolen_size.
302  */
303 static u32 __init i830_stolen_base(int num, int slot, int func, size_t stolen_size)
304 {
305 	return i830_mem_size() - i830_tseg_size() - stolen_size;
306 }
307 
308 static u32 __init i845_stolen_base(int num, int slot, int func, size_t stolen_size)
309 {
310 	return i830_mem_size() - i845_tseg_size() - stolen_size;
311 }
312 
313 static u32 __init i85x_stolen_base(int num, int slot, int func, size_t stolen_size)
314 {
315 	return i85x_mem_size() - i85x_tseg_size() - stolen_size;
316 }
317 
318 static u32 __init i865_stolen_base(int num, int slot, int func, size_t stolen_size)
319 {
320 	/*
321 	 * FIXME is the graphics stolen memory region
322 	 * always at TOUD? Ie. is it always the last
323 	 * one to be allocated by the BIOS?
324 	 */
325 	return read_pci_config_16(0, 0, 0, I865_TOUD) << 16;
326 }
327 
328 static size_t __init i830_stolen_size(int num, int slot, int func)
329 {
330 	size_t stolen_size;
331 	u16 gmch_ctrl;
332 
333 	gmch_ctrl = read_pci_config_16(0, 0, 0, I830_GMCH_CTRL);
334 
335 	switch (gmch_ctrl & I830_GMCH_GMS_MASK) {
336 	case I830_GMCH_GMS_STOLEN_512:
337 		stolen_size = KB(512);
338 		break;
339 	case I830_GMCH_GMS_STOLEN_1024:
340 		stolen_size = MB(1);
341 		break;
342 	case I830_GMCH_GMS_STOLEN_8192:
343 		stolen_size = MB(8);
344 		break;
345 	case I830_GMCH_GMS_LOCAL:
346 		/* local memory isn't part of the normal address space */
347 		stolen_size = 0;
348 		break;
349 	default:
350 		return 0;
351 	}
352 
353 	return stolen_size;
354 }
355 
356 static size_t __init gen3_stolen_size(int num, int slot, int func)
357 {
358 	size_t stolen_size;
359 	u16 gmch_ctrl;
360 
361 	gmch_ctrl = read_pci_config_16(0, 0, 0, I830_GMCH_CTRL);
362 
363 	switch (gmch_ctrl & I855_GMCH_GMS_MASK) {
364 	case I855_GMCH_GMS_STOLEN_1M:
365 		stolen_size = MB(1);
366 		break;
367 	case I855_GMCH_GMS_STOLEN_4M:
368 		stolen_size = MB(4);
369 		break;
370 	case I855_GMCH_GMS_STOLEN_8M:
371 		stolen_size = MB(8);
372 		break;
373 	case I855_GMCH_GMS_STOLEN_16M:
374 		stolen_size = MB(16);
375 		break;
376 	case I855_GMCH_GMS_STOLEN_32M:
377 		stolen_size = MB(32);
378 		break;
379 	case I915_GMCH_GMS_STOLEN_48M:
380 		stolen_size = MB(48);
381 		break;
382 	case I915_GMCH_GMS_STOLEN_64M:
383 		stolen_size = MB(64);
384 		break;
385 	case G33_GMCH_GMS_STOLEN_128M:
386 		stolen_size = MB(128);
387 		break;
388 	case G33_GMCH_GMS_STOLEN_256M:
389 		stolen_size = MB(256);
390 		break;
391 	case INTEL_GMCH_GMS_STOLEN_96M:
392 		stolen_size = MB(96);
393 		break;
394 	case INTEL_GMCH_GMS_STOLEN_160M:
395 		stolen_size = MB(160);
396 		break;
397 	case INTEL_GMCH_GMS_STOLEN_224M:
398 		stolen_size = MB(224);
399 		break;
400 	case INTEL_GMCH_GMS_STOLEN_352M:
401 		stolen_size = MB(352);
402 		break;
403 	default:
404 		stolen_size = 0;
405 		break;
406 	}
407 
408 	return stolen_size;
409 }
410 
411 static size_t __init gen6_stolen_size(int num, int slot, int func)
412 {
413 	u16 gmch_ctrl;
414 
415 	gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
416 	gmch_ctrl >>= SNB_GMCH_GMS_SHIFT;
417 	gmch_ctrl &= SNB_GMCH_GMS_MASK;
418 
419 	return gmch_ctrl << 25; /* 32 MB units */
420 }
421 
422 static size_t __init gen8_stolen_size(int num, int slot, int func)
423 {
424 	u16 gmch_ctrl;
425 
426 	gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
427 	gmch_ctrl >>= BDW_GMCH_GMS_SHIFT;
428 	gmch_ctrl &= BDW_GMCH_GMS_MASK;
429 	return gmch_ctrl << 25; /* 32 MB units */
430 }
431 
432 static size_t __init chv_stolen_size(int num, int slot, int func)
433 {
434 	u16 gmch_ctrl;
435 
436 	gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
437 	gmch_ctrl >>= SNB_GMCH_GMS_SHIFT;
438 	gmch_ctrl &= SNB_GMCH_GMS_MASK;
439 
440 	/*
441 	 * 0x0  to 0x10: 32MB increments starting at 0MB
442 	 * 0x11 to 0x16: 4MB increments starting at 8MB
443 	 * 0x17 to 0x1d: 4MB increments start at 36MB
444 	 */
445 	if (gmch_ctrl < 0x11)
446 		return gmch_ctrl << 25;
447 	else if (gmch_ctrl < 0x17)
448 		return (gmch_ctrl - 0x11 + 2) << 22;
449 	else
450 		return (gmch_ctrl - 0x17 + 9) << 22;
451 }
452 
453 struct intel_stolen_funcs {
454 	size_t (*size)(int num, int slot, int func);
455 	u32 (*base)(int num, int slot, int func, size_t size);
456 };
457 
458 static const struct intel_stolen_funcs i830_stolen_funcs __initconst = {
459 	.base = i830_stolen_base,
460 	.size = i830_stolen_size,
461 };
462 
463 static const struct intel_stolen_funcs i845_stolen_funcs __initconst = {
464 	.base = i845_stolen_base,
465 	.size = i830_stolen_size,
466 };
467 
468 static const struct intel_stolen_funcs i85x_stolen_funcs __initconst = {
469 	.base = i85x_stolen_base,
470 	.size = gen3_stolen_size,
471 };
472 
473 static const struct intel_stolen_funcs i865_stolen_funcs __initconst = {
474 	.base = i865_stolen_base,
475 	.size = gen3_stolen_size,
476 };
477 
478 static const struct intel_stolen_funcs gen3_stolen_funcs __initconst = {
479 	.base = intel_stolen_base,
480 	.size = gen3_stolen_size,
481 };
482 
483 static const struct intel_stolen_funcs gen6_stolen_funcs __initconst = {
484 	.base = intel_stolen_base,
485 	.size = gen6_stolen_size,
486 };
487 
488 static const struct intel_stolen_funcs gen8_stolen_funcs __initconst = {
489 	.base = intel_stolen_base,
490 	.size = gen8_stolen_size,
491 };
492 
493 static const struct intel_stolen_funcs chv_stolen_funcs __initconst = {
494 	.base = intel_stolen_base,
495 	.size = chv_stolen_size,
496 };
497 
498 static const struct pci_device_id intel_stolen_ids[] __initconst = {
499 	INTEL_I830_IDS(&i830_stolen_funcs),
500 	INTEL_I845G_IDS(&i845_stolen_funcs),
501 	INTEL_I85X_IDS(&i85x_stolen_funcs),
502 	INTEL_I865G_IDS(&i865_stolen_funcs),
503 	INTEL_I915G_IDS(&gen3_stolen_funcs),
504 	INTEL_I915GM_IDS(&gen3_stolen_funcs),
505 	INTEL_I945G_IDS(&gen3_stolen_funcs),
506 	INTEL_I945GM_IDS(&gen3_stolen_funcs),
507 	INTEL_VLV_M_IDS(&gen6_stolen_funcs),
508 	INTEL_VLV_D_IDS(&gen6_stolen_funcs),
509 	INTEL_PINEVIEW_IDS(&gen3_stolen_funcs),
510 	INTEL_I965G_IDS(&gen3_stolen_funcs),
511 	INTEL_G33_IDS(&gen3_stolen_funcs),
512 	INTEL_I965GM_IDS(&gen3_stolen_funcs),
513 	INTEL_GM45_IDS(&gen3_stolen_funcs),
514 	INTEL_G45_IDS(&gen3_stolen_funcs),
515 	INTEL_IRONLAKE_D_IDS(&gen3_stolen_funcs),
516 	INTEL_IRONLAKE_M_IDS(&gen3_stolen_funcs),
517 	INTEL_SNB_D_IDS(&gen6_stolen_funcs),
518 	INTEL_SNB_M_IDS(&gen6_stolen_funcs),
519 	INTEL_IVB_M_IDS(&gen6_stolen_funcs),
520 	INTEL_IVB_D_IDS(&gen6_stolen_funcs),
521 	INTEL_HSW_D_IDS(&gen6_stolen_funcs),
522 	INTEL_HSW_M_IDS(&gen6_stolen_funcs),
523 	INTEL_BDW_M_IDS(&gen8_stolen_funcs),
524 	INTEL_BDW_D_IDS(&gen8_stolen_funcs),
525 	INTEL_CHV_IDS(&chv_stolen_funcs),
526 };
527 
528 static void __init intel_graphics_stolen(int num, int slot, int func)
529 {
530 	size_t size;
531 	int i;
532 	u32 start;
533 	u16 device, subvendor, subdevice;
534 
535 	device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID);
536 	subvendor = read_pci_config_16(num, slot, func,
537 				       PCI_SUBSYSTEM_VENDOR_ID);
538 	subdevice = read_pci_config_16(num, slot, func, PCI_SUBSYSTEM_ID);
539 
540 	for (i = 0; i < ARRAY_SIZE(intel_stolen_ids); i++) {
541 		if (intel_stolen_ids[i].device == device) {
542 			const struct intel_stolen_funcs *stolen_funcs =
543 				(const struct intel_stolen_funcs *)intel_stolen_ids[i].driver_data;
544 			size = stolen_funcs->size(num, slot, func);
545 			start = stolen_funcs->base(num, slot, func, size);
546 			if (size && start) {
547 				printk(KERN_INFO "Reserving Intel graphics stolen memory at 0x%x-0x%x\n",
548 				       start, start + (u32)size - 1);
549 				/* Mark this space as reserved */
550 				e820_add_region(start, size, E820_RESERVED);
551 				sanitize_e820_map(e820.map,
552 						  ARRAY_SIZE(e820.map),
553 						  &e820.nr_map);
554 			}
555 			return;
556 		}
557 	}
558 }
559 
560 static void __init force_disable_hpet(int num, int slot, int func)
561 {
562 #ifdef CONFIG_HPET_TIMER
563 	boot_hpet_disable = 1;
564 	pr_info("x86/hpet: Will disable the HPET for this platform because it's not reliable\n");
565 #endif
566 }
567 
568 
569 #define QFLAG_APPLY_ONCE 	0x1
570 #define QFLAG_APPLIED		0x2
571 #define QFLAG_DONE		(QFLAG_APPLY_ONCE|QFLAG_APPLIED)
572 struct chipset {
573 	u32 vendor;
574 	u32 device;
575 	u32 class;
576 	u32 class_mask;
577 	u32 flags;
578 	void (*f)(int num, int slot, int func);
579 };
580 
581 /*
582  * Only works for devices on the root bus. If you add any devices
583  * not on bus 0 readd another loop level in early_quirks(). But
584  * be careful because at least the Nvidia quirk here relies on
585  * only matching on bus 0.
586  */
587 static struct chipset early_qrk[] __initdata = {
588 	{ PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
589 	  PCI_CLASS_BRIDGE_PCI, PCI_ANY_ID, QFLAG_APPLY_ONCE, nvidia_bugs },
590 	{ PCI_VENDOR_ID_VIA, PCI_ANY_ID,
591 	  PCI_CLASS_BRIDGE_PCI, PCI_ANY_ID, QFLAG_APPLY_ONCE, via_bugs },
592 	{ PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB,
593 	  PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, fix_hypertransport_config },
594 	{ PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_IXP400_SMBUS,
595 	  PCI_CLASS_SERIAL_SMBUS, PCI_ANY_ID, 0, ati_bugs },
596 	{ PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS,
597 	  PCI_CLASS_SERIAL_SMBUS, PCI_ANY_ID, 0, ati_bugs_contd },
598 	{ PCI_VENDOR_ID_INTEL, 0x3403, PCI_CLASS_BRIDGE_HOST,
599 	  PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
600 	{ PCI_VENDOR_ID_INTEL, 0x3405, PCI_CLASS_BRIDGE_HOST,
601 	  PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
602 	{ PCI_VENDOR_ID_INTEL, 0x3406, PCI_CLASS_BRIDGE_HOST,
603 	  PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
604 	{ PCI_VENDOR_ID_INTEL, PCI_ANY_ID, PCI_CLASS_DISPLAY_VGA, PCI_ANY_ID,
605 	  QFLAG_APPLY_ONCE, intel_graphics_stolen },
606 	/*
607 	 * HPET on current version of Baytrail platform has accuracy
608 	 * problems, disable it for now:
609 	 */
610 	{ PCI_VENDOR_ID_INTEL, 0x0f00,
611 		PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
612 	{}
613 };
614 
615 /**
616  * check_dev_quirk - apply early quirks to a given PCI device
617  * @num: bus number
618  * @slot: slot number
619  * @func: PCI function
620  *
621  * Check the vendor & device ID against the early quirks table.
622  *
623  * If the device is single function, let early_quirks() know so we don't
624  * poke at this device again.
625  */
626 static int __init check_dev_quirk(int num, int slot, int func)
627 {
628 	u16 class;
629 	u16 vendor;
630 	u16 device;
631 	u8 type;
632 	int i;
633 
634 	class = read_pci_config_16(num, slot, func, PCI_CLASS_DEVICE);
635 
636 	if (class == 0xffff)
637 		return -1; /* no class, treat as single function */
638 
639 	vendor = read_pci_config_16(num, slot, func, PCI_VENDOR_ID);
640 
641 	device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID);
642 
643 	for (i = 0; early_qrk[i].f != NULL; i++) {
644 		if (((early_qrk[i].vendor == PCI_ANY_ID) ||
645 			(early_qrk[i].vendor == vendor)) &&
646 			((early_qrk[i].device == PCI_ANY_ID) ||
647 			(early_qrk[i].device == device)) &&
648 			(!((early_qrk[i].class ^ class) &
649 			    early_qrk[i].class_mask))) {
650 				if ((early_qrk[i].flags &
651 				     QFLAG_DONE) != QFLAG_DONE)
652 					early_qrk[i].f(num, slot, func);
653 				early_qrk[i].flags |= QFLAG_APPLIED;
654 			}
655 	}
656 
657 	type = read_pci_config_byte(num, slot, func,
658 				    PCI_HEADER_TYPE);
659 	if (!(type & 0x80))
660 		return -1;
661 
662 	return 0;
663 }
664 
665 void __init early_quirks(void)
666 {
667 	int slot, func;
668 
669 	if (!early_pci_allowed())
670 		return;
671 
672 	/* Poor man's PCI discovery */
673 	/* Only scan the root bus */
674 	for (slot = 0; slot < 32; slot++)
675 		for (func = 0; func < 8; func++) {
676 			/* Only probe function 0 on single fn devices */
677 			if (check_dev_quirk(0, slot, func))
678 				break;
679 		}
680 }
681