arch/x86/pci/mmconfig_64.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 #include <asm/pci_x86.h>
  14
  15 #define PREFIX "PCI: "
  16
  17 static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
  18 {
  19         struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
  20
  21         if (cfg && cfg->virt)
  22                 return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
  23         return NULL;
  24 }
  25
  26 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
  27                           unsigned int devfn, int reg, int len, u32 *value)
  28 {
  29         char __iomem *addr;
  30
  31         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  32         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
  33 err:            *value = -1;
  34                 return -EINVAL;
  35         }
  36
  37         addr = pci_dev_base(seg, bus, devfn);
  38         if (!addr)
  39                 goto err;
  40
  41         switch (len) {
  42         case 1:
  43                 *value = mmio_config_readb(addr + reg);
  44                 break;
  45         case 2:
  46                 *value = mmio_config_readw(addr + reg);
  47                 break;
  48         case 4:
  49                 *value = mmio_config_readl(addr + reg);
  50                 break;
  51         }
  52
  53         return 0;
  54 }
  55
  56 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
  57                            unsigned int devfn, int reg, int len, u32 value)
  58 {
  59         char __iomem *addr;
  60
  61         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  62         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
  63                 return -EINVAL;
  64
  65         addr = pci_dev_base(seg, bus, devfn);
  66         if (!addr)
  67                 return -EINVAL;
  68
  69         switch (len) {
  70         case 1:
  71                 mmio_config_writeb(addr + reg, value);
  72                 break;
  73         case 2:
  74                 mmio_config_writew(addr + reg, value);
  75                 break;
  76         case 4:
  77                 mmio_config_writel(addr + reg, value);
  78                 break;
  79         }
  80
  81         return 0;
  82 }
  83
  84 static const struct pci_raw_ops pci_mmcfg = {
  85         .read =         pci_mmcfg_read,
  86         .write =        pci_mmcfg_write,
  87 };
  88
  89 static void __iomem * __init mcfg_ioremap(struct pci_mmcfg_region *cfg)
  90 {
  91         void __iomem *addr;
  92         u64 start, size;
  93         int num_buses;
  94
  95         start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
  96         num_buses = cfg->end_bus - cfg->start_bus + 1;
  97         size = PCI_MMCFG_BUS_OFFSET(num_buses);
  98         addr = ioremap_nocache(start, size);
  99         if (addr)
 100                 addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus);
 101         return addr;
 102 }
 103
 104 int __init pci_mmcfg_arch_init(void)
 105 {
 106         struct pci_mmcfg_region *cfg;
 107
 108         list_for_each_entry(cfg, &pci_mmcfg_list, list) {
 109                 cfg->virt = mcfg_ioremap(cfg);
 110                 if (!cfg->virt) {
 111                         printk(KERN_ERR PREFIX "can't map MMCONFIG at %pR\n",
 112                                &cfg->res);
 113                         pci_mmcfg_arch_free();
 114                         return 0;
 115                 }
 116         }
 117         raw_pci_ext_ops = &pci_mmcfg;
 118         return 1;
 119 }
 120
 121 void __init pci_mmcfg_arch_free(void)
 122 {
 123         struct pci_mmcfg_region *cfg;
 124
 125         list_for_each_entry(cfg, &pci_mmcfg_list, list) {
 126                 if (cfg->virt) {
 127                         iounmap(cfg->virt + PCI_MMCFG_BUS_OFFSET(cfg->start_bus));
 128                         cfg->virt = NULL;
 129                 }
 130         }
 131 }