1 // SPDX-License-Identifier: GPL-2.0
2 /* Various workarounds for chipset bugs.
3 This code runs very early and can't use the regular PCI subsystem
4 The entries are keyed to PCI bridges which usually identify chipsets
6 This is only for whole classes of chipsets with specific problems which
7 need early invasive action (e.g. before the timers are initialized).
8 Most PCI device specific workarounds can be done later and should be
10 Mainboard specific bugs should be handled by DMI entries.
11 CPU specific bugs in setup.c */
13 #include <linux/pci.h>
14 #include <linux/acpi.h>
15 #include <linux/delay.h>
16 #include <linux/pci_ids.h>
17 #include <linux/bcma/bcma.h>
18 #include <linux/bcma/bcma_regs.h>
19 #include <linux/platform_data/x86/apple.h>
20 #include <drm/i915_drm.h>
21 #include <asm/pci-direct.h>
23 #include <asm/io_apic.h>
26 #include <asm/iommu.h>
28 #include <asm/irq_remapping.h>
29 #include <asm/early_ioremap.h>
31 #define dev_err(msg) pr_err("pci 0000:%02x:%02x.%d: %s", bus, slot, func, msg)
33 static void __init fix_hypertransport_config(int num, int slot, int func)
37 * we found a hypertransport bus
38 * make sure that we are broadcasting
39 * interrupts to all cpus on the ht bus
40 * if we're using extended apic ids
42 htcfg = read_pci_config(num, slot, func, 0x68);
43 if (htcfg & (1 << 18)) {
44 printk(KERN_INFO "Detected use of extended apic ids "
45 "on hypertransport bus\n");
46 if ((htcfg & (1 << 17)) == 0) {
47 printk(KERN_INFO "Enabling hypertransport extended "
48 "apic interrupt broadcast\n");
49 printk(KERN_INFO "Note this is a bios bug, "
50 "please contact your hw vendor\n");
52 write_pci_config(num, slot, func, 0x68, htcfg);
59 static void __init via_bugs(int num, int slot, int func)
61 #ifdef CONFIG_GART_IOMMU
62 if ((max_pfn > MAX_DMA32_PFN || force_iommu) &&
63 !gart_iommu_aperture_allowed) {
65 "Looks like a VIA chipset. Disabling IOMMU."
66 " Override with iommu=allowed\n");
67 gart_iommu_aperture_disabled = 1;
73 #ifdef CONFIG_X86_IO_APIC
75 static int __init nvidia_hpet_check(struct acpi_table_header *header)
79 #endif /* CONFIG_X86_IO_APIC */
80 #endif /* CONFIG_ACPI */
82 static void __init nvidia_bugs(int num, int slot, int func)
85 #ifdef CONFIG_X86_IO_APIC
87 * Only applies to Nvidia root ports (bus 0) and not to
88 * Nvidia graphics cards with PCI ports on secondary buses.
94 * All timer overrides on Nvidia are
95 * wrong unless HPET is enabled.
96 * Unfortunately that's not true on many Asus boards.
97 * We don't know yet how to detect this automatically, but
98 * at least allow a command line override.
100 if (acpi_use_timer_override)
103 if (acpi_table_parse(ACPI_SIG_HPET, nvidia_hpet_check)) {
104 acpi_skip_timer_override = 1;
105 printk(KERN_INFO "Nvidia board "
106 "detected. Ignoring ACPI "
107 "timer override.\n");
108 printk(KERN_INFO "If you got timer trouble "
109 "try acpi_use_timer_override\n");
113 /* RED-PEN skip them on mptables too? */
117 #if defined(CONFIG_ACPI) && defined(CONFIG_X86_IO_APIC)
118 static u32 __init ati_ixp4x0_rev(int num, int slot, int func)
123 b = read_pci_config_byte(num, slot, func, 0xac);
125 write_pci_config_byte(num, slot, func, 0xac, b);
127 d = read_pci_config(num, slot, func, 0x70);
129 write_pci_config(num, slot, func, 0x70, d);
131 d = read_pci_config(num, slot, func, 0x8);
136 static void __init ati_bugs(int num, int slot, int func)
141 if (acpi_use_timer_override)
144 d = ati_ixp4x0_rev(num, slot, func);
146 acpi_skip_timer_override = 1;
148 /* check for IRQ0 interrupt swap */
149 outb(0x72, 0xcd6); b = inb(0xcd7);
151 acpi_skip_timer_override = 1;
154 if (acpi_skip_timer_override) {
155 printk(KERN_INFO "SB4X0 revision 0x%x\n", d);
156 printk(KERN_INFO "Ignoring ACPI timer override.\n");
157 printk(KERN_INFO "If you got timer trouble "
158 "try acpi_use_timer_override\n");
162 static u32 __init ati_sbx00_rev(int num, int slot, int func)
166 d = read_pci_config(num, slot, func, 0x8);
172 static void __init ati_bugs_contd(int num, int slot, int func)
176 rev = ati_sbx00_rev(num, slot, func);
178 acpi_fix_pin2_polarity = 1;
181 * SB600: revisions 0x11, 0x12, 0x13, 0x14, ...
182 * SB700: revisions 0x39, 0x3a, ...
183 * SB800: revisions 0x40, 0x41, ...
188 if (acpi_use_timer_override)
191 /* check for IRQ0 interrupt swap */
192 d = read_pci_config(num, slot, func, 0x64);
194 acpi_skip_timer_override = 1;
196 if (acpi_skip_timer_override) {
197 printk(KERN_INFO "SB600 revision 0x%x\n", rev);
198 printk(KERN_INFO "Ignoring ACPI timer override.\n");
199 printk(KERN_INFO "If you got timer trouble "
200 "try acpi_use_timer_override\n");
204 static void __init ati_bugs(int num, int slot, int func)
208 static void __init ati_bugs_contd(int num, int slot, int func)
213 static void __init intel_remapping_check(int num, int slot, int func)
218 device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID);
219 revision = read_pci_config_byte(num, slot, func, PCI_REVISION_ID);
222 * Revision <= 13 of all triggering devices id in this quirk
223 * have a problem draining interrupts when irq remapping is
224 * enabled, and should be flagged as broken. Additionally
225 * revision 0x22 of device id 0x3405 has this problem.
227 if (revision <= 0x13)
228 set_irq_remapping_broken();
229 else if (device == 0x3405 && revision == 0x22)
230 set_irq_remapping_broken();
234 * Systems with Intel graphics controllers set aside memory exclusively
235 * for gfx driver use. This memory is not marked in the E820 as reserved
236 * or as RAM, and so is subject to overlap from E820 manipulation later
237 * in the boot process. On some systems, MMIO space is allocated on top,
238 * despite the efforts of the "RAM buffer" approach, which simply rounds
239 * memory boundaries up to 64M to try to catch space that may decode
240 * as RAM and so is not suitable for MMIO.
243 #define KB(x) ((x) * 1024UL)
244 #define MB(x) (KB (KB (x)))
246 static size_t __init i830_tseg_size(void)
248 u8 esmramc = read_pci_config_byte(0, 0, 0, I830_ESMRAMC);
250 if (!(esmramc & TSEG_ENABLE))
253 if (esmramc & I830_TSEG_SIZE_1M)
259 static size_t __init i845_tseg_size(void)
261 u8 esmramc = read_pci_config_byte(0, 0, 0, I845_ESMRAMC);
262 u8 tseg_size = esmramc & I845_TSEG_SIZE_MASK;
264 if (!(esmramc & TSEG_ENABLE))
268 case I845_TSEG_SIZE_512K: return KB(512);
269 case I845_TSEG_SIZE_1M: return MB(1);
271 WARN(1, "Unknown ESMRAMC value: %x!\n", esmramc);
276 static size_t __init i85x_tseg_size(void)
278 u8 esmramc = read_pci_config_byte(0, 0, 0, I85X_ESMRAMC);
280 if (!(esmramc & TSEG_ENABLE))
286 static size_t __init i830_mem_size(void)
288 return read_pci_config_byte(0, 0, 0, I830_DRB3) * MB(32);
291 static size_t __init i85x_mem_size(void)
293 return read_pci_config_byte(0, 0, 1, I85X_DRB3) * MB(32);
297 * On 830/845/85x the stolen memory base isn't available in any
298 * register. We need to calculate it as TOM-TSEG_SIZE-stolen_size.
300 static phys_addr_t __init i830_stolen_base(int num, int slot, int func,
303 return (phys_addr_t)i830_mem_size() - i830_tseg_size() - stolen_size;
306 static phys_addr_t __init i845_stolen_base(int num, int slot, int func,
309 return (phys_addr_t)i830_mem_size() - i845_tseg_size() - stolen_size;
312 static phys_addr_t __init i85x_stolen_base(int num, int slot, int func,
315 return (phys_addr_t)i85x_mem_size() - i85x_tseg_size() - stolen_size;
318 static phys_addr_t __init i865_stolen_base(int num, int slot, int func,
323 toud = read_pci_config_16(0, 0, 0, I865_TOUD);
325 return (phys_addr_t)(toud << 16) + i845_tseg_size();
328 static phys_addr_t __init gen3_stolen_base(int num, int slot, int func,
333 /* Almost universally we can find the Graphics Base of Stolen Memory
334 * at register BSM (0x5c) in the igfx configuration space. On a few
335 * (desktop) machines this is also mirrored in the bridge device at
336 * different locations, or in the MCHBAR.
338 bsm = read_pci_config(num, slot, func, INTEL_BSM);
340 return (phys_addr_t)bsm & INTEL_BSM_MASK;
343 static size_t __init i830_stolen_size(int num, int slot, int func)
348 gmch_ctrl = read_pci_config_16(0, 0, 0, I830_GMCH_CTRL);
349 gms = gmch_ctrl & I830_GMCH_GMS_MASK;
352 case I830_GMCH_GMS_STOLEN_512: return KB(512);
353 case I830_GMCH_GMS_STOLEN_1024: return MB(1);
354 case I830_GMCH_GMS_STOLEN_8192: return MB(8);
355 /* local memory isn't part of the normal address space */
356 case I830_GMCH_GMS_LOCAL: return 0;
358 WARN(1, "Unknown GMCH_CTRL value: %x!\n", gmch_ctrl);
364 static size_t __init gen3_stolen_size(int num, int slot, int func)
369 gmch_ctrl = read_pci_config_16(0, 0, 0, I830_GMCH_CTRL);
370 gms = gmch_ctrl & I855_GMCH_GMS_MASK;
373 case I855_GMCH_GMS_STOLEN_1M: return MB(1);
374 case I855_GMCH_GMS_STOLEN_4M: return MB(4);
375 case I855_GMCH_GMS_STOLEN_8M: return MB(8);
376 case I855_GMCH_GMS_STOLEN_16M: return MB(16);
377 case I855_GMCH_GMS_STOLEN_32M: return MB(32);
378 case I915_GMCH_GMS_STOLEN_48M: return MB(48);
379 case I915_GMCH_GMS_STOLEN_64M: return MB(64);
380 case G33_GMCH_GMS_STOLEN_128M: return MB(128);
381 case G33_GMCH_GMS_STOLEN_256M: return MB(256);
382 case INTEL_GMCH_GMS_STOLEN_96M: return MB(96);
383 case INTEL_GMCH_GMS_STOLEN_160M:return MB(160);
384 case INTEL_GMCH_GMS_STOLEN_224M:return MB(224);
385 case INTEL_GMCH_GMS_STOLEN_352M:return MB(352);
387 WARN(1, "Unknown GMCH_CTRL value: %x!\n", gmch_ctrl);
393 static size_t __init gen6_stolen_size(int num, int slot, int func)
398 gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
399 gms = (gmch_ctrl >> SNB_GMCH_GMS_SHIFT) & SNB_GMCH_GMS_MASK;
401 return (size_t)gms * MB(32);
404 static size_t __init gen8_stolen_size(int num, int slot, int func)
409 gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
410 gms = (gmch_ctrl >> BDW_GMCH_GMS_SHIFT) & BDW_GMCH_GMS_MASK;
412 return (size_t)gms * MB(32);
415 static size_t __init chv_stolen_size(int num, int slot, int func)
420 gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
421 gms = (gmch_ctrl >> SNB_GMCH_GMS_SHIFT) & SNB_GMCH_GMS_MASK;
424 * 0x0 to 0x10: 32MB increments starting at 0MB
425 * 0x11 to 0x16: 4MB increments starting at 8MB
426 * 0x17 to 0x1d: 4MB increments start at 36MB
429 return (size_t)gms * MB(32);
431 return (size_t)(gms - 0x11 + 2) * MB(4);
433 return (size_t)(gms - 0x17 + 9) * MB(4);
436 static size_t __init gen9_stolen_size(int num, int slot, int func)
441 gmch_ctrl = read_pci_config_16(num, slot, func, SNB_GMCH_CTRL);
442 gms = (gmch_ctrl >> BDW_GMCH_GMS_SHIFT) & BDW_GMCH_GMS_MASK;
444 /* 0x0 to 0xef: 32MB increments starting at 0MB */
445 /* 0xf0 to 0xfe: 4MB increments starting at 4MB */
447 return (size_t)gms * MB(32);
449 return (size_t)(gms - 0xf0 + 1) * MB(4);
452 struct intel_early_ops {
453 size_t (*stolen_size)(int num, int slot, int func);
454 phys_addr_t (*stolen_base)(int num, int slot, int func, size_t size);
457 static const struct intel_early_ops i830_early_ops __initconst = {
458 .stolen_base = i830_stolen_base,
459 .stolen_size = i830_stolen_size,
462 static const struct intel_early_ops i845_early_ops __initconst = {
463 .stolen_base = i845_stolen_base,
464 .stolen_size = i830_stolen_size,
467 static const struct intel_early_ops i85x_early_ops __initconst = {
468 .stolen_base = i85x_stolen_base,
469 .stolen_size = gen3_stolen_size,
472 static const struct intel_early_ops i865_early_ops __initconst = {
473 .stolen_base = i865_stolen_base,
474 .stolen_size = gen3_stolen_size,
477 static const struct intel_early_ops gen3_early_ops __initconst = {
478 .stolen_base = gen3_stolen_base,
479 .stolen_size = gen3_stolen_size,
482 static const struct intel_early_ops gen6_early_ops __initconst = {
483 .stolen_base = gen3_stolen_base,
484 .stolen_size = gen6_stolen_size,
487 static const struct intel_early_ops gen8_early_ops __initconst = {
488 .stolen_base = gen3_stolen_base,
489 .stolen_size = gen8_stolen_size,
492 static const struct intel_early_ops gen9_early_ops __initconst = {
493 .stolen_base = gen3_stolen_base,
494 .stolen_size = gen9_stolen_size,
497 static const struct intel_early_ops chv_early_ops __initconst = {
498 .stolen_base = gen3_stolen_base,
499 .stolen_size = chv_stolen_size,
502 static const struct pci_device_id intel_early_ids[] __initconst = {
503 INTEL_I830_IDS(&i830_early_ops),
504 INTEL_I845G_IDS(&i845_early_ops),
505 INTEL_I85X_IDS(&i85x_early_ops),
506 INTEL_I865G_IDS(&i865_early_ops),
507 INTEL_I915G_IDS(&gen3_early_ops),
508 INTEL_I915GM_IDS(&gen3_early_ops),
509 INTEL_I945G_IDS(&gen3_early_ops),
510 INTEL_I945GM_IDS(&gen3_early_ops),
511 INTEL_VLV_IDS(&gen6_early_ops),
512 INTEL_PINEVIEW_IDS(&gen3_early_ops),
513 INTEL_I965G_IDS(&gen3_early_ops),
514 INTEL_G33_IDS(&gen3_early_ops),
515 INTEL_I965GM_IDS(&gen3_early_ops),
516 INTEL_GM45_IDS(&gen3_early_ops),
517 INTEL_G45_IDS(&gen3_early_ops),
518 INTEL_IRONLAKE_D_IDS(&gen3_early_ops),
519 INTEL_IRONLAKE_M_IDS(&gen3_early_ops),
520 INTEL_SNB_D_IDS(&gen6_early_ops),
521 INTEL_SNB_M_IDS(&gen6_early_ops),
522 INTEL_IVB_M_IDS(&gen6_early_ops),
523 INTEL_IVB_D_IDS(&gen6_early_ops),
524 INTEL_HSW_IDS(&gen6_early_ops),
525 INTEL_BDW_IDS(&gen8_early_ops),
526 INTEL_CHV_IDS(&chv_early_ops),
527 INTEL_SKL_IDS(&gen9_early_ops),
528 INTEL_BXT_IDS(&gen9_early_ops),
529 INTEL_KBL_IDS(&gen9_early_ops),
530 INTEL_CFL_IDS(&gen9_early_ops),
531 INTEL_GLK_IDS(&gen9_early_ops),
532 INTEL_CNL_IDS(&gen9_early_ops),
536 intel_graphics_stolen(int num, int slot, int func,
537 const struct intel_early_ops *early_ops)
539 phys_addr_t base, end;
542 size = early_ops->stolen_size(num, slot, func);
543 base = early_ops->stolen_base(num, slot, func, size);
548 end = base + size - 1;
549 printk(KERN_INFO "Reserving Intel graphics memory at %pa-%pa\n",
552 /* Mark this space as reserved */
553 e820__range_add(base, size, E820_TYPE_RESERVED);
554 e820__update_table(e820_table);
557 static void __init intel_graphics_quirks(int num, int slot, int func)
559 const struct intel_early_ops *early_ops;
563 device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID);
565 for (i = 0; i < ARRAY_SIZE(intel_early_ids); i++) {
566 kernel_ulong_t driver_data = intel_early_ids[i].driver_data;
568 if (intel_early_ids[i].device != device)
571 early_ops = (typeof(early_ops))driver_data;
573 intel_graphics_stolen(num, slot, func, early_ops);
579 static void __init force_disable_hpet(int num, int slot, int func)
581 #ifdef CONFIG_HPET_TIMER
582 boot_hpet_disable = true;
583 pr_info("x86/hpet: Will disable the HPET for this platform because it's not reliable\n");
587 #define BCM4331_MMIO_SIZE 16384
588 #define BCM4331_PM_CAP 0x40
589 #define bcma_aread32(reg) ioread32(mmio + 1 * BCMA_CORE_SIZE + reg)
590 #define bcma_awrite32(reg, val) iowrite32(val, mmio + 1 * BCMA_CORE_SIZE + reg)
592 static void __init apple_airport_reset(int bus, int slot, int func)
599 if (!x86_apple_machine)
602 /* Card may have been put into PCI_D3hot by grub quirk */
603 pmcsr = read_pci_config_16(bus, slot, func, BCM4331_PM_CAP + PCI_PM_CTRL);
605 if ((pmcsr & PCI_PM_CTRL_STATE_MASK) != PCI_D0) {
606 pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
607 write_pci_config_16(bus, slot, func, BCM4331_PM_CAP + PCI_PM_CTRL, pmcsr);
610 pmcsr = read_pci_config_16(bus, slot, func, BCM4331_PM_CAP + PCI_PM_CTRL);
611 if ((pmcsr & PCI_PM_CTRL_STATE_MASK) != PCI_D0) {
612 dev_err("Cannot power up Apple AirPort card\n");
617 addr = read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_0);
618 addr |= (u64)read_pci_config(bus, slot, func, PCI_BASE_ADDRESS_1) << 32;
619 addr &= PCI_BASE_ADDRESS_MEM_MASK;
621 mmio = early_ioremap(addr, BCM4331_MMIO_SIZE);
623 dev_err("Cannot iomap Apple AirPort card\n");
627 pr_info("Resetting Apple AirPort card (left enabled by EFI)\n");
629 for (i = 0; bcma_aread32(BCMA_RESET_ST) && i < 30; i++)
632 bcma_awrite32(BCMA_RESET_CTL, BCMA_RESET_CTL_RESET);
633 bcma_aread32(BCMA_RESET_CTL);
636 bcma_awrite32(BCMA_RESET_CTL, 0);
637 bcma_aread32(BCMA_RESET_CTL);
640 early_iounmap(mmio, BCM4331_MMIO_SIZE);
643 #define QFLAG_APPLY_ONCE 0x1
644 #define QFLAG_APPLIED 0x2
645 #define QFLAG_DONE (QFLAG_APPLY_ONCE|QFLAG_APPLIED)
652 void (*f)(int num, int slot, int func);
655 static struct chipset early_qrk[] __initdata = {
656 { PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
657 PCI_CLASS_BRIDGE_PCI, PCI_ANY_ID, QFLAG_APPLY_ONCE, nvidia_bugs },
658 { PCI_VENDOR_ID_VIA, PCI_ANY_ID,
659 PCI_CLASS_BRIDGE_PCI, PCI_ANY_ID, QFLAG_APPLY_ONCE, via_bugs },
660 { PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB,
661 PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, fix_hypertransport_config },
662 { PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_IXP400_SMBUS,
663 PCI_CLASS_SERIAL_SMBUS, PCI_ANY_ID, 0, ati_bugs },
664 { PCI_VENDOR_ID_ATI, PCI_DEVICE_ID_ATI_SBX00_SMBUS,
665 PCI_CLASS_SERIAL_SMBUS, PCI_ANY_ID, 0, ati_bugs_contd },
666 { PCI_VENDOR_ID_INTEL, 0x3403, PCI_CLASS_BRIDGE_HOST,
667 PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
668 { PCI_VENDOR_ID_INTEL, 0x3405, PCI_CLASS_BRIDGE_HOST,
669 PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
670 { PCI_VENDOR_ID_INTEL, 0x3406, PCI_CLASS_BRIDGE_HOST,
671 PCI_BASE_CLASS_BRIDGE, 0, intel_remapping_check },
672 { PCI_VENDOR_ID_INTEL, PCI_ANY_ID, PCI_CLASS_DISPLAY_VGA, PCI_ANY_ID,
673 QFLAG_APPLY_ONCE, intel_graphics_quirks },
675 * HPET on the current version of the Baytrail platform has accuracy
676 * problems: it will halt in deep idle state - so we disable it.
678 * More details can be found in section 18.10.1.3 of the datasheet:
680 * http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/atom-z8000-datasheet-vol-1.pdf
682 { PCI_VENDOR_ID_INTEL, 0x0f00,
683 PCI_CLASS_BRIDGE_HOST, PCI_ANY_ID, 0, force_disable_hpet},
684 { PCI_VENDOR_ID_BROADCOM, 0x4331,
685 PCI_CLASS_NETWORK_OTHER, PCI_ANY_ID, 0, apple_airport_reset},
689 static void __init early_pci_scan_bus(int bus);
692 * check_dev_quirk - apply early quirks to a given PCI device
695 * @func: PCI function
697 * Check the vendor & device ID against the early quirks table.
699 * If the device is single function, let early_pci_scan_bus() know so we don't
700 * poke at this device again.
702 static int __init check_dev_quirk(int num, int slot, int func)
711 class = read_pci_config_16(num, slot, func, PCI_CLASS_DEVICE);
714 return -1; /* no class, treat as single function */
716 vendor = read_pci_config_16(num, slot, func, PCI_VENDOR_ID);
718 device = read_pci_config_16(num, slot, func, PCI_DEVICE_ID);
720 for (i = 0; early_qrk[i].f != NULL; i++) {
721 if (((early_qrk[i].vendor == PCI_ANY_ID) ||
722 (early_qrk[i].vendor == vendor)) &&
723 ((early_qrk[i].device == PCI_ANY_ID) ||
724 (early_qrk[i].device == device)) &&
725 (!((early_qrk[i].class ^ class) &
726 early_qrk[i].class_mask))) {
727 if ((early_qrk[i].flags &
728 QFLAG_DONE) != QFLAG_DONE)
729 early_qrk[i].f(num, slot, func);
730 early_qrk[i].flags |= QFLAG_APPLIED;
734 type = read_pci_config_byte(num, slot, func,
737 if ((type & 0x7f) == PCI_HEADER_TYPE_BRIDGE) {
738 sec = read_pci_config_byte(num, slot, func, PCI_SECONDARY_BUS);
740 early_pci_scan_bus(sec);
749 static void __init early_pci_scan_bus(int bus)
753 /* Poor man's PCI discovery */
754 for (slot = 0; slot < 32; slot++)
755 for (func = 0; func < 8; func++) {
756 /* Only probe function 0 on single fn devices */
757 if (check_dev_quirk(bus, slot, func))
762 void __init early_quirks(void)
764 if (!early_pci_allowed())
767 early_pci_scan_bus(0);