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 /* Static virtual mapping of the MMCONFIG aperture */
  16 struct mmcfg_virt {
  17         struct acpi_mcfg_allocation *cfg;
  18         char __iomem *virt;
  19 };
  20 static struct mmcfg_virt *pci_mmcfg_virt;
  21
  22 static char __iomem *get_virt(unsigned int seg, unsigned bus)
  23 {
  24         struct acpi_mcfg_allocation *cfg;
  25         int cfg_num;
  26
  27         for (cfg_num = 0; cfg_num < pci_mmcfg_config_num; cfg_num++) {
  28                 cfg = pci_mmcfg_virt[cfg_num].cfg;
  29                 if (cfg->pci_segment == seg &&
  30                     (cfg->start_bus_number <= bus) &&
  31                     (cfg->end_bus_number >= bus))
  32                         return pci_mmcfg_virt[cfg_num].virt;
  33         }
  34
  35         /* Fall back to type 0 */
  36         return NULL;
  37 }
  38
  39 static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
  40 {
  41         char __iomem *addr;
  42
  43         addr = get_virt(seg, bus);
  44         if (!addr)
  45                 return NULL;
  46         return addr + ((bus << 20) | (devfn << 12));
  47 }
  48
  49 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
  50                           unsigned int devfn, int reg, int len, u32 *value)
  51 {
  52         char __iomem *addr;
  53
  54         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  55         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
  56 err:            *value = -1;
  57                 return -EINVAL;
  58         }
  59
  60         addr = pci_dev_base(seg, bus, devfn);
  61         if (!addr)
  62                 goto err;
  63
  64         switch (len) {
  65         case 1:
  66                 *value = mmio_config_readb(addr + reg);
  67                 break;
  68         case 2:
  69                 *value = mmio_config_readw(addr + reg);
  70                 break;
  71         case 4:
  72                 *value = mmio_config_readl(addr + reg);
  73                 break;
  74         }
  75
  76         return 0;
  77 }
  78
  79 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
  80                            unsigned int devfn, int reg, int len, u32 value)
  81 {
  82         char __iomem *addr;
  83
  84         /* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  85         if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
  86                 return -EINVAL;
  87
  88         addr = pci_dev_base(seg, bus, devfn);
  89         if (!addr)
  90                 return -EINVAL;
  91
  92         switch (len) {
  93         case 1:
  94                 mmio_config_writeb(addr + reg, value);
  95                 break;
  96         case 2:
  97                 mmio_config_writew(addr + reg, value);
  98                 break;
  99         case 4:
 100                 mmio_config_writel(addr + reg, value);
 101                 break;
 102         }
 103
 104         return 0;
 105 }
 106
 107 static struct pci_raw_ops pci_mmcfg = {
 108         .read =         pci_mmcfg_read,
 109         .write =        pci_mmcfg_write,
 110 };
 111
 112 static void __iomem * __init mcfg_ioremap(struct acpi_mcfg_allocation *cfg)
 113 {
 114         void __iomem *addr;
 115         u32 size;
 116
 117         size = (cfg->end_bus_number + 1) << 20;
 118         addr = ioremap_nocache(cfg->address, size);
 119         if (addr) {
 120                 printk(KERN_INFO "PCI: Using MMCONFIG at %Lx - %Lx\n",
 121                        cfg->address, cfg->address + size - 1);
 122         }
 123         return addr;
 124 }
 125
 126 int __init pci_mmcfg_arch_init(void)
 127 {
 128         int i;
 129         pci_mmcfg_virt = kzalloc(sizeof(*pci_mmcfg_virt) *
 130                                  pci_mmcfg_config_num, GFP_KERNEL);
 131         if (pci_mmcfg_virt == NULL) {
 132                 printk(KERN_ERR "PCI: Can not allocate memory for mmconfig structures\n");
 133                 return 0;
 134         }
 135
 136         for (i = 0; i < pci_mmcfg_config_num; ++i) {
 137                 pci_mmcfg_virt[i].cfg = &pci_mmcfg_config[i];
 138                 pci_mmcfg_virt[i].virt = mcfg_ioremap(&pci_mmcfg_config[i]);
 139                 if (!pci_mmcfg_virt[i].virt) {
 140                         printk(KERN_ERR "PCI: Cannot map mmconfig aperture for "
 141                                         "segment %d\n",
 142                                 pci_mmcfg_config[i].pci_segment);
 143                         pci_mmcfg_arch_free();
 144                         return 0;
 145                 }
 146         }
 147         raw_pci_ext_ops = &pci_mmcfg;
 148         return 1;
 149 }
 150
 151 void __init pci_mmcfg_arch_free(void)
 152 {
 153         int i;
 154
 155         if (pci_mmcfg_virt == NULL)
 156                 return;
 157
 158         for (i = 0; i < pci_mmcfg_config_num; ++i) {
 159                 if (pci_mmcfg_virt[i].virt) {
 160                         iounmap(pci_mmcfg_virt[i].virt);
 161                         pci_mmcfg_virt[i].virt = NULL;
 162                         pci_mmcfg_virt[i].cfg = NULL;
 163                 }
 164         }
 165
 166         kfree(pci_mmcfg_virt);
 167         pci_mmcfg_virt = NULL;
 168 }