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 __init 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 __init 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 __init 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 struct chipset {
  75         u16 vendor;
  76         void (*f)(void);
  77 };
  78
  79 static struct chipset early_qrk[] __initdata = {
  80         { PCI_VENDOR_ID_NVIDIA, nvidia_bugs },
  81         { PCI_VENDOR_ID_VIA, via_bugs },
  82         { PCI_VENDOR_ID_ATI, ati_bugs },
  83         {}
  84 };
  85
  86 void __init early_quirks(void)
  87 {
  88         int num, slot, func;
  89
  90         if (!early_pci_allowed())
  91                 return;
  92
  93         /* Poor man's PCI discovery */
  94         for (num = 0; num < 32; num++) {
  95                 for (slot = 0; slot < 32; slot++) {
  96                         for (func = 0; func < 8; func++) {
  97                                 u32 class;
  98                                 u32 vendor;
  99                                 u8 type;
 100                                 int i;
 101                                 class = read_pci_config(num,slot,func,
 102                                                         PCI_CLASS_REVISION);
 103                                 if (class == 0xffffffff)
 104                                         break;
 105
 106                                 if ((class >> 16) != PCI_CLASS_BRIDGE_PCI)
 107                                         continue;
 108
 109                                 vendor = read_pci_config(num, slot, func,
 110                                                          PCI_VENDOR_ID);
 111                                 vendor &= 0xffff;
 112
 113                                 for (i = 0; early_qrk[i].f; i++)
 114                                         if (early_qrk[i].vendor == vendor) {
 115                                                 early_qrk[i].f();
 116                                                 return;
 117                                         }
 118
 119                                 type = read_pci_config_byte(num, slot, func,
 120                                                             PCI_HEADER_TYPE);
 121                                 if (!(type & 0x80))
 122                                         break;
 123                         }
 124                 }
 125         }
 126 }