Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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 "pci.h" |
| 11 | |
| 12 | #define MMCONFIG_APER_SIZE (256*1024*1024) |
| 13 | |
| 14 | /* The physical address of the MMCONFIG aperture. Set from ACPI tables. */ |
| 15 | u32 pci_mmcfg_base_addr; |
| 16 | |
| 17 | /* Static virtual mapping of the MMCONFIG aperture */ |
| 18 | char *pci_mmcfg_virt; |
| 19 | |
| 20 | static inline char *pci_dev_base(unsigned int bus, unsigned int devfn) |
| 21 | { |
| 22 | return pci_mmcfg_virt + ((bus << 20) | (devfn << 12)); |
| 23 | } |
| 24 | |
| 25 | static int pci_mmcfg_read(unsigned int seg, unsigned int bus, |
| 26 | unsigned int devfn, int reg, int len, u32 *value) |
| 27 | { |
| 28 | char *addr = pci_dev_base(bus, devfn); |
| 29 | |
| 30 | if (unlikely(!value || (bus > 255) || (devfn > 255) || (reg > 4095))) |
| 31 | return -EINVAL; |
| 32 | |
| 33 | switch (len) { |
| 34 | case 1: |
| 35 | *value = readb(addr + reg); |
| 36 | break; |
| 37 | case 2: |
| 38 | *value = readw(addr + reg); |
| 39 | break; |
| 40 | case 4: |
| 41 | *value = readl(addr + reg); |
| 42 | break; |
| 43 | } |
| 44 | |
| 45 | return 0; |
| 46 | } |
| 47 | |
| 48 | static int pci_mmcfg_write(unsigned int seg, unsigned int bus, |
| 49 | unsigned int devfn, int reg, int len, u32 value) |
| 50 | { |
| 51 | char *addr = pci_dev_base(bus,devfn); |
| 52 | |
| 53 | if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) |
| 54 | return -EINVAL; |
| 55 | |
| 56 | switch (len) { |
| 57 | case 1: |
| 58 | writeb(value, addr + reg); |
| 59 | break; |
| 60 | case 2: |
| 61 | writew(value, addr + reg); |
| 62 | break; |
| 63 | case 4: |
| 64 | writel(value, addr + reg); |
| 65 | break; |
| 66 | } |
| 67 | |
| 68 | return 0; |
| 69 | } |
| 70 | |
| 71 | static struct pci_raw_ops pci_mmcfg = { |
| 72 | .read = pci_mmcfg_read, |
| 73 | .write = pci_mmcfg_write, |
| 74 | }; |
| 75 | |
| 76 | static int __init pci_mmcfg_init(void) |
| 77 | { |
| 78 | if ((pci_probe & PCI_PROBE_MMCONF) == 0) |
| 79 | return 0; |
| 80 | if (!pci_mmcfg_base_addr) |
| 81 | return 0; |
| 82 | |
| 83 | /* Kludge for now. Don't use mmconfig on AMD systems because |
| 84 | those have some busses where mmconfig doesn't work, |
| 85 | and we don't parse ACPI MCFG well enough to handle that. |
| 86 | Remove when proper handling is added. */ |
| 87 | if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD) |
| 88 | return 0; |
| 89 | |
| 90 | /* RED-PEN i386 doesn't do _nocache right now */ |
| 91 | pci_mmcfg_virt = ioremap_nocache(pci_mmcfg_base_addr, MMCONFIG_APER_SIZE); |
| 92 | if (!pci_mmcfg_virt) { |
| 93 | printk("PCI: Cannot map mmconfig aperture\n"); |
| 94 | return 0; |
| 95 | } |
| 96 | |
| 97 | printk(KERN_INFO "PCI: Using MMCONFIG at %x\n", pci_mmcfg_base_addr); |
| 98 | raw_pci_ops = &pci_mmcfg; |
| 99 | pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF; |
| 100 | |
| 101 | return 0; |
| 102 | } |
| 103 | |
| 104 | arch_initcall(pci_mmcfg_init); |