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 <linux/rcupdate.h>
  15 #include <asm/e820.h>
  16 #include <asm/pci_x86.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         rcu_read_lock();
  64         base = get_base_addr(seg, bus, devfn);
  65         if (!base) {
  66                 rcu_read_unlock();
  67                 goto err;
  68         }
  69
  70         raw_spin_lock_irqsave(&pci_config_lock, flags);
  71
  72         pci_exp_set_dev_base(base, bus, devfn);
  73
  74         switch (len) {
  75         case 1:
  76                 *value = mmio_config_readb(mmcfg_virt_addr + reg);
  77                 break;
  78         case 2:
  79                 *value = mmio_config_readw(mmcfg_virt_addr + reg);
  80                 break;
  81         case 4:
  82                 *value = mmio_config_readl(mmcfg_virt_addr + reg);
  83                 break;
  84         }
  85         raw_spin_unlock_irqrestore(&pci_config_lock, flags);
  86         rcu_read_unlock();
  87
  88         return 0;
  89 }
  90
  91 static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
  92                            unsigned int devfn, int reg, int len, u32 value)
  93 {
  94         unsigned long flags;
  95         u32 base;
  96
  97         if ((bus > 255) || (devfn > 255) || (reg > 4095))
  98                 return -EINVAL;
  99
 100         rcu_read_lock();
 101         base = get_base_addr(seg, bus, devfn);
 102         if (!base) {
 103                 rcu_read_unlock();
 104                 return -EINVAL;
 105         }
 106
 107         raw_spin_lock_irqsave(&pci_config_lock, flags);
 108
 109         pci_exp_set_dev_base(base, bus, devfn);
 110
 111         switch (len) {
 112         case 1:
 113                 mmio_config_writeb(mmcfg_virt_addr + reg, value);
 114                 break;
 115         case 2:
 116                 mmio_config_writew(mmcfg_virt_addr + reg, value);
 117                 break;
 118         case 4:
 119                 mmio_config_writel(mmcfg_virt_addr + reg, value);
 120                 break;
 121         }
 122         raw_spin_unlock_irqrestore(&pci_config_lock, flags);
 123         rcu_read_unlock();
 124
 125         return 0;
 126 }
 127
 128 const 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 }
 143
 144 int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg)
 145 {
 146         return 0;
 147 }
 148
 149 void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg)
 150 {
 151         unsigned long flags;
 152
 153         /* Invalidate the cached mmcfg map entry. */
 154         raw_spin_lock_irqsave(&pci_config_lock, flags);
 155         mmcfg_last_accessed_device = 0;
 156         raw_spin_unlock_irqrestore(&pci_config_lock, flags);
 157 }