arch/i386/pci/mmconfig.c

   1 /*
   2  * Copyright (C) 2004 Matthew Wilcox <matthew@wil.cx>
   3  * Copyright (C) 2004 Intel Corp.
   4  *
   5  * This code is released under the GNU General Public License version 2.
   6  */
   7
   8 /*
   9  * mmconfig.c - Low-level direct PCI config space access via MMCONFIG
  10  */
  11
  12 #include <linux/pci.h>
  13 #include <linux/init.h>
  14 #include <linux/acpi.h>
  15 #include <asm/e820.h>
  16 #include "pci.h"
  17
  18 /* Assume systems with more busses have correct MCFG */
  19 #define mmcfg_virt_addr ((void __iomem *) fix_to_virt(FIX_PCIE_MCFG))
  20
  21 /* The base address of the last MMCONFIG device accessed */
  22 static u32 mmcfg_last_accessed_device;
  23 static int mmcfg_last_accessed_cpu;
  24
  25 /*
  26  * Functions for accessing PCI configuration space with MMCONFIG accesses
  27  */
  28 static u32 get_base_addr(unsigned int seg, int bus, unsigned devfn)
  29 {
  30         struct acpi_mcfg_allocation *cfg;
  31         int cfg_num;
  32
  33         if (seg == 0 && bus < PCI_MMCFG_MAX_CHECK_BUS &&
  34             test_bit(PCI_SLOT(devfn) + 32*bus, pci_mmcfg_fallback_slots))
  35                 return 0;
  36
  37         for (cfg_num = 0; cfg_num < pci_mmcfg_config_num; cfg_num++) {
  38                 cfg = &pci_mmcfg_config[cfg_num];
  39                 if (cfg->pci_segment == seg &&
  40                     (cfg->start_bus_number <= bus) &&
  41                     (cfg->end_bus_number >= bus))
  42                         return cfg->address;
  43         }
  44
  45         /* Fall back to type 0 */
  46         return 0;
  47 }
  48
  49 /*
  50  * This is always called under pci_config_lock
  51  */
  52 static void pci_exp_set_dev_base(unsigned int base, int bus, int devfn)
  53 {
  54         u32 dev_base = base | (bus << 20) | (devfn << 12);
  55         int cpu = smp_processor_id();
  56         if (dev_base != mmcfg_last_accessed_device ||
  57             cpu != mmcfg_last_accessed_cpu) {
  58                 mmcfg_last_accessed_device = dev_base;
  59                 mmcfg_last_accessed_cpu = cpu;
  60                 set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
  61         }
  62 }
  63
  64 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
  65                           unsigned int devfn, int reg, int len, u32 *value)
  66 {
  67         unsigned long flags;
  68         u32 base;
  69
  70         if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
  71                 *value = -1;
  72                 return -EINVAL;
  73         }
  74
  75         base = get_base_addr(seg, bus, devfn);
  76         if (!base)
  77                 return pci_conf1_read(seg,bus,devfn,reg,len,value);
  78
  79         spin_lock_irqsave(&pci_config_lock, flags);
  80
  81         pci_exp_set_dev_base(base, bus, devfn);
  82
  83         switch (len) {
  84         case 1:
  85                 *value = readb(mmcfg_virt_addr + reg);
  86                 break;
  87         case 2:
  88                 *value = readw(mmcfg_virt_addr + reg);
  89                 break;
  90         case 4:
  91                 *value = readl(mmcfg_virt_addr + reg);
  92                 break;
  93         }
  94
  95         spin_unlock_irqrestore(&pci_config_lock, flags);
  96
  97         return 0;
  98 }
  99
 100 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
 101                            unsigned int devfn, int reg, int len, u32 value)
 102 {
 103         unsigned long flags;
 104         u32 base;
 105
 106         if ((bus > 255) || (devfn > 255) || (reg > 4095))
 107                 return -EINVAL;
 108
 109         base = get_base_addr(seg, bus, devfn);
 110         if (!base)
 111                 return pci_conf1_write(seg,bus,devfn,reg,len,value);
 112
 113         spin_lock_irqsave(&pci_config_lock, flags);
 114
 115         pci_exp_set_dev_base(base, bus, devfn);
 116
 117         switch (len) {
 118         case 1:
 119                 writeb(value, mmcfg_virt_addr + reg);
 120                 break;
 121         case 2:
 122                 writew(value, mmcfg_virt_addr + reg);
 123                 break;
 124         case 4:
 125                 writel(value, mmcfg_virt_addr + reg);
 126                 break;
 127         }
 128
 129         spin_unlock_irqrestore(&pci_config_lock, flags);
 130
 131         return 0;
 132 }
 133
 134 static struct pci_raw_ops pci_mmcfg = {
 135         .read =         pci_mmcfg_read,
 136         .write =        pci_mmcfg_write,
 137 };
 138
 139 int __init pci_mmcfg_arch_reachable(unsigned int seg, unsigned int bus,
 140                                     unsigned int devfn)
 141 {
 142         return get_base_addr(seg, bus, devfn) != 0;
 143 }
 144
 145 int __init pci_mmcfg_arch_init(void)
 146 {
 147         printk(KERN_INFO "PCI: Using MMCONFIG\n");
 148         raw_pci_ops = &pci_mmcfg;
 149         return 1;
 150 }