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 acpi_mcfg_allocation *cfg;
  31         int cfg_num;
  32
  33         for (cfg_num = 0; cfg_num < pci_mmcfg_config_num; cfg_num++) {
  34                 cfg = &pci_mmcfg_config[cfg_num];
  35                 if (cfg->pci_segment == seg &&
  36                     (cfg->start_bus_number <= bus) &&
  37                     (cfg->end_bus_number >= bus))
  38                         return cfg->address;
  39         }
  40
  41         /* Fall back to type 0 */
  42         return 0;
  43 }
  44
  45 /*
  46  * This is always called under pci_config_lock
  47  */
  48 static void pci_exp_set_dev_base(unsigned int base, int bus, int devfn)
  49 {
  50         u32 dev_base = base | (bus << 20) | (devfn << 12);
  51         int cpu = smp_processor_id();
  52         if (dev_base != mmcfg_last_accessed_device ||
  53             cpu != mmcfg_last_accessed_cpu) {
  54                 mmcfg_last_accessed_device = dev_base;
  55                 mmcfg_last_accessed_cpu = cpu;
  56                 set_fixmap_nocache(FIX_PCIE_MCFG, dev_base);
  57         }
  58 }
  59
  60 static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
  61                           unsigned int devfn, int reg, int len, u32 *value)
  62 {
  63         unsigned long flags;
  64         u32 base;
  65
  66         if ((bus > 255) || (devfn > 255) || (reg > 4095)) {
  67 err:            *value = -1;
  68                 return -EINVAL;
  69         }
  70
  71         base = get_base_addr(seg, bus, devfn);
  72         if (!base)
  73                 goto err;
  74
  75         spin_lock_irqsave(&pci_config_lock, flags);
  76
  77         pci_exp_set_dev_base(base, bus, devfn);
  78
  79         switch (len) {
  80         case 1:
  81                 *value = mmio_config_readb(mmcfg_virt_addr + reg);
  82                 break;
  83         case 2:
  84                 *value = mmio_config_readw(mmcfg_virt_addr + reg);
  85                 break;
  86         case 4:
  87                 *value = mmio_config_readl(mmcfg_virt_addr + reg);
  88                 break;
  89         }
  90         spin_unlock_irqrestore(&pci_config_lock, flags);
  91
  92         return 0;
  93 }
  94
  95 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
  96                            unsigned int devfn, int reg, int len, u32 value)
  97 {
  98         unsigned long flags;
  99         u32 base;
 100
 101         if ((bus > 255) || (devfn > 255) || (reg > 4095))
 102                 return -EINVAL;
 103
 104         base = get_base_addr(seg, bus, devfn);
 105         if (!base)
 106                 return -EINVAL;
 107
 108         spin_lock_irqsave(&pci_config_lock, flags);
 109
 110         pci_exp_set_dev_base(base, bus, devfn);
 111
 112         switch (len) {
 113         case 1:
 114                 mmio_config_writeb(mmcfg_virt_addr + reg, value);
 115                 break;
 116         case 2:
 117                 mmio_config_writew(mmcfg_virt_addr + reg, value);
 118                 break;
 119         case 4:
 120                 mmio_config_writel(mmcfg_virt_addr + reg, value);
 121                 break;
 122         }
 123         spin_unlock_irqrestore(&pci_config_lock, flags);
 124
 125         return 0;
 126 }
 127
 128 static struct pci_raw_ops pci_mmcfg = {
 129         .read =         pci_mmcfg_read,
 130         .write =        pci_mmcfg_write,
 131 };
 132
 133 int __init pci_mmcfg_arch_init(void)
 134 {
 135         printk(KERN_INFO "PCI: Using MMCONFIG for extended config space\n");
 136         raw_pci_ext_ops = &pci_mmcfg;
 137         return 1;
 138 }
 139
 140 void __init pci_mmcfg_arch_free(void)
 141 {
 142 }