arch/x86_64/kernel/early-quirks.c

   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 <asm/pci-direct.h>
  16 #include <asm/proto.h>
  17 #include <asm/dma.h>
  18
  19 static void via_bugs(void)
  20 {
  21 #ifdef CONFIG_IOMMU
  22         if ((end_pfn > MAX_DMA32_PFN ||  force_iommu) &&
  23             !iommu_aperture_allowed) {
  24                 printk(KERN_INFO
  25   "Looks like a VIA chipset. Disabling IOMMU. Override with iommu=allowed\n");
  26                 iommu_aperture_disabled = 1;
  27         }
  28 #endif
  29 }
  30
  31 #ifdef CONFIG_ACPI
  32
  33 static int __init nvidia_hpet_check(struct acpi_table_header *header)
  34 {
  35         return 0;
  36 }
  37 #endif
  38
  39 static void nvidia_bugs(void)
  40 {
  41 #ifdef CONFIG_ACPI
  42         /*
  43          * All timer overrides on Nvidia are
  44          * wrong unless HPET is enabled.
  45          * Unfortunately that's not true on many Asus boards.
  46          * We don't know yet how to detect this automatically, but
  47          * at least allow a command line override.
  48          */
  49         if (acpi_use_timer_override)
  50                 return;
  51
  52         if (acpi_table_parse(ACPI_SIG_HPET, nvidia_hpet_check)) {
  53                 acpi_skip_timer_override = 1;
  54                 printk(KERN_INFO "Nvidia board "
  55                        "detected. Ignoring ACPI "
  56                        "timer override.\n");
  57                 printk(KERN_INFO "If you got timer trouble "
  58                         "try acpi_use_timer_override\n");
  59         }
  60 #endif
  61         /* RED-PEN skip them on mptables too? */
  62
  63 }
  64
  65 static void ati_bugs(void)
  66 {
  67         if (timer_over_8254 == 1) {
  68                 timer_over_8254 = 0;
  69                 printk(KERN_INFO
  70                 "ATI board detected. Disabling timer routing over 8254.\n");
  71         }
  72 }
  73
  74 static void intel_bugs(void)
  75 {
  76         u16 device = read_pci_config_16(0, 0, 0, PCI_DEVICE_ID);
  77
  78 #ifdef CONFIG_SMP
  79         if (device == PCI_DEVICE_ID_INTEL_E7320_MCH ||
  80             device == PCI_DEVICE_ID_INTEL_E7520_MCH ||
  81             device == PCI_DEVICE_ID_INTEL_E7525_MCH)
  82                 quirk_intel_irqbalance();
  83 #endif
  84 }
  85
  86 struct chipset {
  87         u16 vendor;
  88         void (*f)(void);
  89 };
  90
  91 static struct chipset early_qrk[] = {
  92         { PCI_VENDOR_ID_NVIDIA, nvidia_bugs },
  93         { PCI_VENDOR_ID_VIA, via_bugs },
  94         { PCI_VENDOR_ID_ATI, ati_bugs },
  95         { PCI_VENDOR_ID_INTEL, intel_bugs},
  96         {}
  97 };
  98
  99 void __init early_quirks(void)
 100 {
 101         int num, slot, func;
 102
 103         if (!early_pci_allowed())
 104                 return;
 105
 106         /* Poor man's PCI discovery */
 107         for (num = 0; num < 32; num++) {
 108                 for (slot = 0; slot < 32; slot++) {
 109                         for (func = 0; func < 8; func++) {
 110                                 u32 class;
 111                                 u32 vendor;
 112                                 u8 type;
 113                                 int i;
 114                                 class = read_pci_config(num,slot,func,
 115                                                         PCI_CLASS_REVISION);
 116                                 if (class == 0xffffffff)
 117                                         break;
 118
 119                                 if ((class >> 16) != PCI_CLASS_BRIDGE_PCI)
 120                                         continue;
 121
 122                                 vendor = read_pci_config(num, slot, func,
 123                                                          PCI_VENDOR_ID);
 124                                 vendor &= 0xffff;
 125
 126                                 for (i = 0; early_qrk[i].f; i++)
 127                                         if (early_qrk[i].vendor == vendor) {
 128                                                 early_qrk[i].f();
 129                                                 return;
 130                                         }
 131
 132                                 type = read_pci_config_byte(num, slot, func,
 133                                                             PCI_HEADER_TYPE);
 134                                 if (!(type & 0x80))
 135                                         break;
 136                         }
 137                 }
 138         }
 139 }