x86_64: abstract how we find the iommu_table for a device
[linux-2.6] / 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 }