arch/x86/pci/mmconfig_32.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 <asm/e820.h>
  15 #include <asm/pci_x86.h>
  16 #include <acpi/acpi.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 pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
  31
  32         if (cfg)
  33                 return cfg->address;
  34         return 0;
  35 }
  36
  37 /*
  38  * This is always called under pci_config_lock
  39  */
  40 static void pci_exp_set_dev_base(unsigned int base, int bus, int devfn)
  41 {
  42         u32 dev_base = base | PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12);
  43         int cpu = smp_processor_id();
  44         if (dev_base != mmcfg_last_accessed_device ||
  45             cpu != mmcfg_last_accessed_cpu) {
  46                 mmcfg_last_accessed_device = dev_base;
  47                 mmcfg_last_accessed_cpu = cpu;
  48                 set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
  49         }
  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         unsigned long flags;
  56         u32 base;
  57
  58         if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
  59 err:            *value = -1;
  60                 return -EINVAL;
  61         }
  62
  63         base = get_base_addr(seg, bus, devfn);
  64         if (!base)
  65                 goto err;
  66
  67         raw_spin_lock_irqsave(&pci_config_lock, flags);
  68
  69         pci_exp_set_dev_base(base, bus, devfn);
  70
  71         switch (len) {
  72         case 1:
  73                 *value = mmio_config_readb(mmcfg_virt_addr + reg);
  74                 break;
  75         case 2:
  76                 *value = mmio_config_readw(mmcfg_virt_addr + reg);
  77                 break;
  78         case 4:
  79                 *value = mmio_config_readl(mmcfg_virt_addr + reg);
  80                 break;
  81         }
  82         raw_spin_unlock_irqrestore(&pci_config_lock, flags);
  83
  84         return 0;
  85 }
  86
  87 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
  88                            unsigned int devfn, int reg, int len, u32 value)
  89 {
  90         unsigned long flags;
  91         u32 base;
  92
  93         if ((bus > 255) || (devfn > 255) || (reg > 4095))
  94                 return -EINVAL;
  95
  96         base = get_base_addr(seg, bus, devfn);
  97         if (!base)
  98                 return -EINVAL;
  99
 100         raw_spin_lock_irqsave(&pci_config_lock, flags);
 101
 102         pci_exp_set_dev_base(base, bus, devfn);
 103
 104         switch (len) {
 105         case 1:
 106                 mmio_config_writeb(mmcfg_virt_addr + reg, value);
 107                 break;
 108         case 2:
 109                 mmio_config_writew(mmcfg_virt_addr + reg, value);
 110                 break;
 111         case 4:
 112                 mmio_config_writel(mmcfg_virt_addr + reg, value);
 113                 break;
 114         }
 115         raw_spin_unlock_irqrestore(&pci_config_lock, flags);
 116
 117         return 0;
 118 }
 119
 120 static const struct pci_raw_ops pci_mmcfg = {
 121         .read =         pci_mmcfg_read,
 122         .write =        pci_mmcfg_write,
 123 };
 124
 125 int __init pci_mmcfg_arch_init(void)
 126 {
 127         printk(KERN_INFO "PCI: Using MMCONFIG for extended config space\n");
 128         raw_pci_ext_ops = &pci_mmcfg;
 129         return 1;
 130 }
 131
 132 void __init pci_mmcfg_arch_free(void)
 133 {
 134 }