arch/x86_64/pci/mmconfig.c

   1 /*
   2  * mmconfig.c - Low-level direct PCI config space access via MMCONFIG
   3  *
   4  * This is an 64bit optimized version that always keeps the full mmconfig
   5  * space mapped. This allows lockless config space operation.
   6  */
   7
   8 #include <linux/pci.h>
   9 #include <linux/init.h>
  10 #include <linux/acpi.h>
  11 #include <linux/bitmap.h>
  12 #include <asm/e820.h>
  13
  14 #include "pci.h"
  15
  16 /* Static virtual mapping of the MMCONFIG aperture */
  17 struct mmcfg_virt {
  18         struct acpi_mcfg_allocation *cfg;
  19         char __iomem *virt;
  20 };
  21 static struct mmcfg_virt *pci_mmcfg_virt;
  22
  23 static char __iomem *get_virt(unsigned int seg, unsigned bus)
  24 {
  25         struct acpi_mcfg_allocation *cfg;
  26         int cfg_num;
  27
  28         for (cfg_num = 0; cfg_num < pci_mmcfg_config_num; cfg_num++) {
  29                 cfg = pci_mmcfg_virt[cfg_num].cfg;
  30                 if (cfg->pci_segment == seg &&
  31                     (cfg->start_bus_number <= bus) &&
  32                     (cfg->end_bus_number >= bus))
  33                         return pci_mmcfg_virt[cfg_num].virt;
  34         }
  35
  36         /* Fall back to type 0 */
  37         return NULL;
  38 }
  39
  40 static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
  41 {
  42         char __iomem *addr;
  43         if (seg == 0 && bus < PCI_MMCFG_MAX_CHECK_BUS &&
  44                 test_bit(32*bus + PCI_SLOT(devfn), pci_mmcfg_fallback_slots))
  45                 return NULL;
  46         addr = get_virt(seg, bus);
  47         if (!addr)
  48                 return NULL;
  49         return addr + ((bus << 20) | (devfn << 12));
  50 }
  51
  52 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
  53                           unsigned int devfn, int reg, int len, u32 *value)
  54 {
  55         char __iomem *addr;
  56
  57         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  58         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
  59                 *value = -1;
  60                 return -EINVAL;
  61         }
  62
  63         addr = pci_dev_base(seg, bus, devfn);
  64         if (!addr)
  65                 return pci_conf1_read(seg,bus,devfn,reg,len,value);
  66
  67         switch (len) {
  68         case 1:
  69                 *value = readb(addr + reg);
  70                 break;
  71         case 2:
  72                 *value = readw(addr + reg);
  73                 break;
  74         case 4:
  75                 *value = readl(addr + reg);
  76                 break;
  77         }
  78
  79         return 0;
  80 }
  81
  82 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
  83                            unsigned int devfn, int reg, int len, u32 value)
  84 {
  85         char __iomem *addr;
  86
  87         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  88         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
  89                 return -EINVAL;
  90
  91         addr = pci_dev_base(seg, bus, devfn);
  92         if (!addr)
  93                 return pci_conf1_write(seg,bus,devfn,reg,len,value);
  94
  95         switch (len) {
  96         case 1:
  97                 writeb(value, addr + reg);
  98                 break;
  99         case 2:
 100                 writew(value, addr + reg);
 101                 break;
 102         case 4:
 103                 writel(value, addr + reg);
 104                 break;
 105         }
 106
 107         return 0;
 108 }
 109
 110 static struct pci_raw_ops pci_mmcfg = {
 111         .read =         pci_mmcfg_read,
 112         .write =        pci_mmcfg_write,
 113 };
 114
 115 static void __iomem * __init mcfg_ioremap(struct acpi_mcfg_allocation *cfg)
 116 {
 117         void __iomem *addr;
 118         u32 size;
 119
 120         size = (cfg->end_bus_number + 1) << 20;
 121         addr = ioremap_nocache(cfg->address, size);
 122         if (addr) {
 123                 printk(KERN_INFO "PCI: Using MMCONFIG at %Lx - %Lx\n",
 124                        cfg->address, cfg->address + size - 1);
 125         }
 126         return addr;
 127 }
 128
 129 int __init pci_mmcfg_arch_reachable(unsigned int seg, unsigned int bus,
 130                                     unsigned int devfn)
 131 {
 132         return pci_dev_base(seg, bus, devfn) != NULL;
 133 }
 134
 135 int __init pci_mmcfg_arch_init(void)
 136 {
 137         int i;
 138         pci_mmcfg_virt = kmalloc(sizeof(*pci_mmcfg_virt) *
 139                                  pci_mmcfg_config_num, GFP_KERNEL);
 140         if (pci_mmcfg_virt == NULL) {
 141                 printk(KERN_ERR "PCI: Can not allocate memory for mmconfig structures\n");
 142                 return 0;
 143         }
 144
 145         for (i = 0; i < pci_mmcfg_config_num; ++i) {
 146                 pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i];
 147                 pci_mmcfg_virt[i].virt = mcfg_ioremap(&pci_mmcfg_config[i]);
 148                 if (!pci_mmcfg_virt[i].virt) {
 149                         printk(KERN_ERR "PCI: Cannot map mmconfig aperture for "
 150                                         "segment %d\n",
 151                                 pci_mmcfg_config[i].pci_segment);
 152                         return 0;
 153                 }
 154         }
 155         raw_pci_ops = &pci_mmcfg;
 156         return 1;
 157 }