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
  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
  44         addr = get_virt(seg, bus);
  45         if (!addr)
  46                 return NULL;
  47         return addr + ((bus << 20) | (devfn << 12));
  48 }
  49
  50 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
  51                           unsigned int devfn, int reg, int len, u32 *value)
  52 {
  53         char __iomem *addr;
  54
  55         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  56         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
  57 err:            *value = -1;
  58                 return -EINVAL;
  59         }
  60
  61         addr = pci_dev_base(seg, bus, devfn);
  62         if (!addr)
  63                 goto err;
  64
  65         switch (len) {
  66         case 1:
  67                 *value = mmio_config_readb(addr + reg);
  68                 break;
  69         case 2:
  70                 *value = mmio_config_readw(addr + reg);
  71                 break;
  72         case 4:
  73                 *value = mmio_config_readl(addr + reg);
  74                 break;
  75         }
  76
  77         return 0;
  78 }
  79
  80 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
  81                            unsigned int devfn, int reg, int len, u32 value)
  82 {
  83         char __iomem *addr;
  84
  85         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  86         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
  87                 return -EINVAL;
  88
  89         addr = pci_dev_base(seg, bus, devfn);
  90         if (!addr)
  91                 return -EINVAL;
  92
  93         switch (len) {
  94         case 1:
  95                 mmio_config_writeb(addr + reg, value);
  96                 break;
  97         case 2:
  98                 mmio_config_writew(addr + reg, value);
  99                 break;
 100         case 4:
 101                 mmio_config_writel(addr + reg, value);
 102                 break;
 103         }
 104
 105         return 0;
 106 }
 107
 108 static struct pci_raw_ops pci_mmcfg = {
 109         .read =         pci_mmcfg_read,
 110         .write =        pci_mmcfg_write,
 111 };
 112
 113 static void __iomem * __init mcfg_ioremap(struct acpi_mcfg_allocation *cfg)
 114 {
 115         void __iomem *addr;
 116         u32 size;
 117
 118         size = (cfg->end_bus_number + 1) << 20;
 119         addr = ioremap_nocache(cfg->address, size);
 120         if (addr) {
 121                 printk(KERN_INFO "PCI: Using MMCONFIG at %Lx - %Lx\n",
 122                        cfg->address, cfg->address + size - 1);
 123         }
 124         return addr;
 125 }
 126
 127 int __init pci_mmcfg_arch_init(void)
 128 {
 129         int i;
 130         pci_mmcfg_virt = kzalloc(sizeof(*pci_mmcfg_virt) *
 131                                  pci_mmcfg_config_num, GFP_KERNEL);
 132         if (pci_mmcfg_virt == NULL) {
 133                 printk(KERN_ERR "PCI: Can not allocate memory for mmconfig structures\n");
 134                 return 0;
 135         }
 136
 137         for (i = 0; i < pci_mmcfg_config_num; ++i) {
 138                 pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i];
 139                 pci_mmcfg_virt[i].virt = mcfg_ioremap(&pci_mmcfg_config[i]);
 140                 if (!pci_mmcfg_virt[i].virt) {
 141                         printk(KERN_ERR "PCI: Cannot map mmconfig aperture for "
 142                                         "segment %d\n",
 143                                 pci_mmcfg_config[i].pci_segment);
 144                         pci_mmcfg_arch_free();
 145                         return 0;
 146                 }
 147         }
 148         raw_pci_ext_ops = &pci_mmcfg;
 149         return 1;
 150 }
 151
 152 void __init pci_mmcfg_arch_free(void)
 153 {
 154         int i;
 155
 156         if (pci_mmcfg_virt == NULL)
 157                 return;
 158
 159         for (i = 0; i < pci_mmcfg_config_num; ++i) {
 160                 if (pci_mmcfg_virt[i].virt) {
 161                         iounmap(pci_mmcfg_virt[i].virt);
 162                         pci_mmcfg_virt[i].virt = NULL;
 163                         pci_mmcfg_virt[i].cfg = NULL;
 164                 }
 165         }
 166
 167         kfree(pci_mmcfg_virt);
 168         pci_mmcfg_virt = NULL;
 169 }