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          */
  49         nvidia_hpet_detected = 0;
  50         acpi_table_parse(ACPI_HPET, nvidia_hpet_check);
  51         if (nvidia_hpet_detected == 0) {
  52                 acpi_skip_timer_override = 1;
  53                 printk(KERN_INFO "Nvidia board "
  54                        "detected. Ignoring ACPI "
  55                        "timer override.\n");
  56         }
  57 #endif
  58         /* RED-PEN skip them on mptables too? */
  59
  60 }
  61
  62 static void ati_bugs(void)
  63 {
  64 #if 1 /* for testing */
  65         printk("ATI board detected\n");
  66 #endif
  67         /* No bugs right now */
  68 }
  69
  70 struct chipset {
  71         u16 vendor;
  72         void (*f)(void);
  73 };
  74
  75 static struct chipset early_qrk[] = {
  76         { PCI_VENDOR_ID_NVIDIA, nvidia_bugs },
  77         { PCI_VENDOR_ID_VIA, via_bugs },
  78         { PCI_VENDOR_ID_ATI, ati_bugs },
  79         {}
  80 };
  81
  82 void __init early_quirks(void)
  83 {
  84         int num, slot, func;
  85
  86         if (!early_pci_allowed())
  87                 return;
  88
  89         /* Poor man's PCI discovery */
  90         for (num = 0; num < 32; num++) {
  91                 for (slot = 0; slot < 32; slot++) {
  92                         for (func = 0; func < 8; func++) {
  93                                 u32 class;
  94                                 u32 vendor;
  95                                 u8 type;
  96                                 int i;
  97                                 class = read_pci_config(num,slot,func,
  98                                                         PCI_CLASS_REVISION);
  99                                 if (class == 0xffffffff)
 100                                         break;
 101
 102                                 if ((class >> 16) != PCI_CLASS_BRIDGE_PCI)
 103                                         continue;
 104
 105                                 vendor = read_pci_config(num, slot, func,
 106                                                          PCI_VENDOR_ID);
 107                                 vendor &= 0xffff;
 108
 109                                 for (i = 0; early_qrk[i].f; i++)
 110                                         if (early_qrk[i].vendor == vendor) {
 111                                                 early_qrk[i].f();
 112                                                 return;
 113                                         }
 114
 115                                 type = read_pci_config_byte(num, slot, func,
 116                                                             PCI_HEADER_TYPE);
 117                                 if (!(type & 0x80))
 118                                         break;
 119                         }
 120                 }
 121         }
 122 }