arch/x86_64/kernel/early-quirks_64.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/iommu.h>
  18 #include <asm/dma.h>
  19
  20 static void __init via_bugs(void)
  21 {
  22 #ifdef CONFIG_IOMMU
  23         if ((end_pfn > MAX_DMA32_PFN ||  force_iommu) &&
  24             !iommu_aperture_allowed) {
  25                 printk(KERN_INFO
  26   "Looks like a VIA chipset. Disabling IOMMU. Override with iommu=allowed\n");
  27                 iommu_aperture_disabled = 1;
  28         }
  29 #endif
  30 }
  31
  32 #ifdef CONFIG_ACPI
  33
  34 static int __init nvidia_hpet_check(struct acpi_table_header *header)
  35 {
  36         return 0;
  37 }
  38 #endif
  39
  40 static void __init nvidia_bugs(void)
  41 {
  42 #ifdef CONFIG_ACPI
  43         /*
  44          * All timer overrides on Nvidia are
  45          * wrong unless HPET is enabled.
  46          * Unfortunately that's not true on many Asus boards.
  47          * We don't know yet how to detect this automatically, but
  48          * at least allow a command line override.
  49          */
  50         if (acpi_use_timer_override)
  51                 return;
  52
  53         if (acpi_table_parse(ACPI_SIG_HPET, nvidia_hpet_check)) {
  54                 acpi_skip_timer_override = 1;
  55                 printk(KERN_INFO "Nvidia board "
  56                        "detected. Ignoring ACPI "
  57                        "timer override.\n");
  58                 printk(KERN_INFO "If you got timer trouble "
  59                         "try acpi_use_timer_override\n");
  60         }
  61 #endif
  62         /* RED-PEN skip them on mptables too? */
  63
  64 }
  65
  66 static void __init ati_bugs(void)
  67 {
  68         if (timer_over_8254 == 1) {
  69                 timer_over_8254 = 0;
  70                 printk(KERN_INFO
  71                 "ATI board detected. Disabling timer routing over 8254.\n");
  72         }
  73 }
  74
  75 struct chipset {
  76         u16 vendor;
  77         void (*f)(void);
  78 };
  79
  80 static struct chipset early_qrk[] __initdata = {
  81         { PCI_VENDOR_ID_NVIDIA, nvidia_bugs },
  82         { PCI_VENDOR_ID_VIA, via_bugs },
  83         { PCI_VENDOR_ID_ATI, ati_bugs },
  84         {}
  85 };
  86
  87 void __init early_quirks(void)
  88 {
  89         int num, slot, func;
  90
  91         if (!early_pci_allowed())
  92                 return;
  93
  94         /* Poor man's PCI discovery */
  95         for (num = 0; num < 32; num++) {
  96                 for (slot = 0; slot < 32; slot++) {
  97                         for (func = 0; func < 8; func++) {
  98                                 u32 class;
  99                                 u32 vendor;
 100                                 u8 type;
 101                                 int i;
 102                                 class = read_pci_config(num,slot,func,
 103                                                         PCI_CLASS_REVISION);
 104                                 if (class == 0xffffffff)
 105                                         break;
 106
 107                                 if ((class >> 16) != PCI_CLASS_BRIDGE_PCI)
 108                                         continue;
 109
 110                                 vendor = read_pci_config(num, slot, func,
 111                                                          PCI_VENDOR_ID);
 112                                 vendor &= 0xffff;
 113
 114                                 for (i = 0; early_qrk[i].f; i++)
 115                                         if (early_qrk[i].vendor == vendor) {
 116                                                 early_qrk[i].f();
 117                                                 return;
 118                                         }
 119
 120                                 type = read_pci_config_byte(num, slot, func,
 121                                                             PCI_HEADER_TYPE);
 122                                 if (!(type & 0x80))
 123                                         break;
 124                         }
 125                 }
 126         }
 127 }