arch/x86/pci/early.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/kernel.h>
   3 #include <linux/pci.h>
   4 #include <asm/pci-direct.h>
   5 #include <asm/io.h>
   6 #include <asm/pci_x86.h>
   7
   8 /* Direct PCI access. This is used for PCI accesses in early boot before
   9    the PCI subsystem works. */
  10
  11 u32 read_pci_config(u8 bus, u8 slot, u8 func, u8 offset)
  12 {
  13         u32 v;
  14         outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  15         v = inl(0xcfc);
  16         return v;
  17 }
  18
  19 u8 read_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset)
  20 {
  21         u8 v;
  22         outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  23         v = inb(0xcfc + (offset&3));
  24         return v;
  25 }
  26
  27 u16 read_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset)
  28 {
  29         u16 v;
  30         outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  31         v = inw(0xcfc + (offset&2));
  32         return v;
  33 }
  34
  35 void write_pci_config(u8 bus, u8 slot, u8 func, u8 offset,
  36                                     u32 val)
  37 {
  38         outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  39         outl(val, 0xcfc);
  40 }
  41
  42 void write_pci_config_byte(u8 bus, u8 slot, u8 func, u8 offset, u8 val)
  43 {
  44         outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  45         outb(val, 0xcfc + (offset&3));
  46 }
  47
  48 void write_pci_config_16(u8 bus, u8 slot, u8 func, u8 offset, u16 val)
  49 {
  50         outl(0x80000000 | (bus<<16) | (slot<<11) | (func<<8) | offset, 0xcf8);
  51         outw(val, 0xcfc + (offset&2));
  52 }
  53
  54 int early_pci_allowed(void)
  55 {
  56         return (pci_probe & (PCI_PROBE_CONF1|PCI_PROBE_NOEARLY)) ==
  57                         PCI_PROBE_CONF1;
  58 }
  59
  60 void early_dump_pci_device(u8 bus, u8 slot, u8 func)
  61 {
  62         int i;
  63         int j;
  64         u32 val;
  65
  66         printk(KERN_INFO "pci 0000:%02x:%02x.%d config space:",
  67                bus, slot, func);
  68
  69         for (i = 0; i < 256; i += 4) {
  70                 if (!(i & 0x0f))
  71                         printk("\n  %02x:",i);
  72
  73                 val = read_pci_config(bus, slot, func, i);
  74                 for (j = 0; j < 4; j++) {
  75                         printk(" %02x", val & 0xff);
  76                         val >>= 8;
  77                 }
  78         }
  79         printk("\n");
  80 }
  81
  82 void early_dump_pci_devices(void)
  83 {
  84         unsigned bus, slot, func;
  85
  86         if (!early_pci_allowed())
  87                 return;
  88
  89         for (bus = 0; bus < 256; bus++) {
  90                 for (slot = 0; slot < 32; slot++) {
  91                         for (func = 0; func < 8; func++) {
  92                                 u32 class;
  93                                 u8 type;
  94
  95                                 class = read_pci_config(bus, slot, func,
  96                                                         PCI_CLASS_REVISION);
  97                                 if (class == 0xffffffff)
  98                                         continue;
  99
 100                                 early_dump_pci_device(bus, slot, func);
 101
 102                                 if (func == 0) {
 103                                         type = read_pci_config_byte(bus, slot,
 104                                                                     func,
 105                                                                PCI_HEADER_TYPE);
 106                                         if (!(type & 0x80))
 107                                                 break;
 108                                 }
 109                         }
 110                 }
 111         }
 112 }