arch/x86/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/dma.h>
  17 #include <asm/io_apic.h>
  18 #include <asm/apic.h>
  19
  20 #ifdef CONFIG_IOMMU
  21 #include <asm/iommu.h>
  22 #endif
  23
  24 static void __init via_bugs(void)
  25 {
  26 #ifdef CONFIG_IOMMU
  27         if ((end_pfn > MAX_DMA32_PFN ||  force_iommu) &&
  28             !iommu_aperture_allowed) {
  29                 printk(KERN_INFO
  30                        "Looks like a VIA chipset. Disabling IOMMU."
  31                        " Override with iommu=allowed\n");
  32                 iommu_aperture_disabled = 1;
  33         }
  34 #endif
  35 }
  36
  37 #ifdef CONFIG_ACPI
  38
  39 static int __init nvidia_hpet_check(struct acpi_table_header *header)
  40 {
  41         return 0;
  42 }
  43 #endif
  44
  45 static void __init nvidia_bugs(void)
  46 {
  47 #ifdef CONFIG_ACPI
  48 #ifdef CONFIG_X86_IO_APIC
  49         /*
  50          * All timer overrides on Nvidia are
  51          * wrong unless HPET is enabled.
  52          * Unfortunately that's not true on many Asus boards.
  53          * We don't know yet how to detect this automatically, but
  54          * at least allow a command line override.
  55          */
  56         if (acpi_use_timer_override)
  57                 return;
  58
  59         if (acpi_table_parse(ACPI_SIG_HPET, nvidia_hpet_check)) {
  60                 acpi_skip_timer_override = 1;
  61                 printk(KERN_INFO "Nvidia board "
  62                        "detected. Ignoring ACPI "
  63                        "timer override.\n");
  64                 printk(KERN_INFO "If you got timer trouble "
  65                         "try acpi_use_timer_override\n");
  66         }
  67 #endif
  68 #endif
  69         /* RED-PEN skip them on mptables too? */
  70
  71 }
  72
  73 static void __init ati_bugs(void)
  74 {
  75 #ifdef CONFIG_X86_IO_APIC
  76         if (timer_over_8254 == 1) {
  77                 timer_over_8254 = 0;
  78                 printk(KERN_INFO
  79                 "ATI board detected. Disabling timer routing over 8254.\n");
  80         }
  81 #endif
  82 }
  83
  84 struct chipset {
  85         u16 vendor;
  86         void (*f)(void);
  87 };
  88
  89 static struct chipset early_qrk[] __initdata = {
  90         { PCI_VENDOR_ID_NVIDIA, nvidia_bugs },
  91         { PCI_VENDOR_ID_VIA, via_bugs },
  92         { PCI_VENDOR_ID_ATI, ati_bugs },
  93         {}
  94 };
  95
  96 void __init early_quirks(void)
  97 {
  98         int num, slot, func;
  99
 100         if (!early_pci_allowed())
 101                 return;
 102
 103         /* Poor man's PCI discovery */
 104         for (num = 0; num < 32; num++) {
 105                 for (slot = 0; slot < 32; slot++) {
 106                         for (func = 0; func < 8; func++) {
 107                                 u32 class;
 108                                 u32 vendor;
 109                                 u8 type;
 110                                 int i;
 111                                 class = read_pci_config(num,slot,func,
 112                                                         PCI_CLASS_REVISION);
 113                                 if (class == 0xffffffff)
 114                                         break;
 115
 116                                 if ((class >> 16) != PCI_CLASS_BRIDGE_PCI)
 117                                         continue;
 118
 119                                 vendor = read_pci_config(num, slot, func,
 120                                                          PCI_VENDOR_ID);
 121                                 vendor &= 0xffff;
 122
 123                                 for (i = 0; early_qrk[i].f; i++)
 124                                         if (early_qrk[i].vendor == vendor) {
 125                                                 early_qrk[i].f();
 126                                                 return;
 127                                         }
 128
 129                                 type = read_pci_config_byte(num, slot, func,
 130                                                             PCI_HEADER_TYPE);
 131                                 if (!(type & 0x80))
 132                                         break;
 133                         }
 134                 }
 135         }
 136 }