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 nvidia_hpet_detected __initdata;
  34
  35 static int __init nvidia_hpet_check(unsigned long phys, unsigned long size)
  36 {
  37         nvidia_hpet_detected = 1;
  38         return 0;
  39 }
  40 #endif
  41
  42 static void nvidia_bugs(void)
  43 {
  44 #ifdef CONFIG_ACPI
  45         /*
  46          * All timer overrides on Nvidia are
  47          * wrong unless HPET is enabled.
  48          * Unfortunately that's not true on many Asus boards.
  49          * We don't know yet how to detect this automatically, but
  50          * at least allow a command line override.
  51          */
  52         if (acpi_use_timer_override)
  53                 return;
  54
  55         nvidia_hpet_detected = 0;
  56         acpi_table_parse(ACPI_HPET, nvidia_hpet_check);
  57         if (nvidia_hpet_detected == 0) {
  58                 acpi_skip_timer_override = 1;
  59                 printk(KERN_INFO "Nvidia board "
  60                        "detected. Ignoring ACPI "
  61                        "timer override.\n");
  62                 printk(KERN_INFO "If you got timer trouble "
  63                         "try acpi_use_timer_override\n");
  64         }
  65 #endif
  66         /* RED-PEN skip them on mptables too? */
  67
  68 }
  69
  70 static void ati_bugs(void)
  71 {
  72         if (timer_over_8254 == 1) {
  73                 timer_over_8254 = 0;
  74                 printk(KERN_INFO
  75                 "ATI board detected. Disabling timer routing over 8254.\n");
  76         }
  77 }
  78
  79 struct chipset {
  80         u16 vendor;
  81         void (*f)(void);
  82 };
  83
  84 static struct chipset early_qrk[] = {
  85         { PCI_VENDOR_ID_NVIDIA, nvidia_bugs },
  86         { PCI_VENDOR_ID_VIA, via_bugs },
  87         { PCI_VENDOR_ID_ATI, ati_bugs },
  88         {}
  89 };
  90
  91 void __init early_quirks(void)
  92 {
  93         int num, slot, func;
  94
  95         if (!early_pci_allowed())
  96                 return;
  97
  98         /* Poor man's PCI discovery */
  99         for (num = 0; num < 32; num++) {
 100                 for (slot = 0; slot < 32; slot++) {
 101                         for (func = 0; func < 8; func++) {
 102                                 u32 class;
 103                                 u32 vendor;
 104                                 u8 type;
 105                                 int i;
 106                                 class = read_pci_config(num,slot,func,
 107                                                         PCI_CLASS_REVISION);
 108                                 if (class == 0xffffffff)
 109                                         break;
 110
 111                                 if ((class >> 16) != PCI_CLASS_BRIDGE_PCI)
 112                                         continue;
 113
 114                                 vendor = read_pci_config(num, slot, func,
 115                                                          PCI_VENDOR_ID);
 116                                 vendor &= 0xffff;
 117
 118                                 for (i = 0; early_qrk[i].f; i++)
 119                                         if (early_qrk[i].vendor == vendor) {
 120                                                 early_qrk[i].f();
 121                                                 return;
 122                                         }
 123
 124                                 type = read_pci_config_byte(num, slot, func,
 125                                                             PCI_HEADER_TYPE);
 126                                 if (!(type & 0x80))
 127                                         break;
 128                         }
 129                 }
 130         }
 131 }