| 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 <linux/rcupdate.h> |
| 13 | #include <asm/e820.h> |
| 14 | #include <asm/pci_x86.h> |
| 15 | |
| 16 | #define PREFIX "PCI: " |
| 17 | |
| 18 | static char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn) |
| 19 | { |
| 20 | struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus); |
| 21 | |
| 22 | if (cfg && cfg->virt) |
| 23 | return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12)); |
| 24 | return NULL; |
| 25 | } |
| 26 | |
| 27 | static int pci_mmcfg_read(unsigned int seg, unsigned int bus, |
| 28 | unsigned int devfn, int reg, int len, u32 *value) |
| 29 | { |
| 30 | char __iomem *addr; |
| 31 | |
| 32 | /* Why do we have this when nobody checks it. How about a BUG()!? -AK */ |
| 33 | if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) { |
| 34 | err: *value = -1; |
| 35 | return -EINVAL; |
| 36 | } |
| 37 | |
| 38 | rcu_read_lock(); |
| 39 | addr = pci_dev_base(seg, bus, devfn); |
| 40 | if (!addr) { |
| 41 | rcu_read_unlock(); |
| 42 | goto err; |
| 43 | } |
| 44 | |
| 45 | switch (len) { |
| 46 | case 1: |
| 47 | *value = mmio_config_readb(addr + reg); |
| 48 | break; |
| 49 | case 2: |
| 50 | *value = mmio_config_readw(addr + reg); |
| 51 | break; |
| 52 | case 4: |
| 53 | *value = mmio_config_readl(addr + reg); |
| 54 | break; |
| 55 | } |
| 56 | rcu_read_unlock(); |
| 57 | |
| 58 | return 0; |
| 59 | } |
| 60 | |
| 61 | static int pci_mmcfg_write(unsigned int seg, unsigned int bus, |
| 62 | unsigned int devfn, int reg, int len, u32 value) |
| 63 | { |
| 64 | char __iomem *addr; |
| 65 | |
| 66 | /* Why do we have this when nobody checks it. How about a BUG()!? -AK */ |
| 67 | if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) |
| 68 | return -EINVAL; |
| 69 | |
| 70 | rcu_read_lock(); |
| 71 | addr = pci_dev_base(seg, bus, devfn); |
| 72 | if (!addr) { |
| 73 | rcu_read_unlock(); |
| 74 | return -EINVAL; |
| 75 | } |
| 76 | |
| 77 | switch (len) { |
| 78 | case 1: |
| 79 | mmio_config_writeb(addr + reg, value); |
| 80 | break; |
| 81 | case 2: |
| 82 | mmio_config_writew(addr + reg, value); |
| 83 | break; |
| 84 | case 4: |
| 85 | mmio_config_writel(addr + reg, value); |
| 86 | break; |
| 87 | } |
| 88 | rcu_read_unlock(); |
| 89 | |
| 90 | return 0; |
| 91 | } |
| 92 | |
| 93 | const struct pci_raw_ops pci_mmcfg = { |
| 94 | .read = pci_mmcfg_read, |
| 95 | .write = pci_mmcfg_write, |
| 96 | }; |
| 97 | |
| 98 | static void __iomem *mcfg_ioremap(struct pci_mmcfg_region *cfg) |
| 99 | { |
| 100 | void __iomem *addr; |
| 101 | u64 start, size; |
| 102 | int num_buses; |
| 103 | |
| 104 | start = cfg->address + PCI_MMCFG_BUS_OFFSET(cfg->start_bus); |
| 105 | num_buses = cfg->end_bus - cfg->start_bus + 1; |
| 106 | size = PCI_MMCFG_BUS_OFFSET(num_buses); |
| 107 | addr = ioremap_nocache(start, size); |
| 108 | if (addr) |
| 109 | addr -= PCI_MMCFG_BUS_OFFSET(cfg->start_bus); |
| 110 | return addr; |
| 111 | } |
| 112 | |
| 113 | int __init pci_mmcfg_arch_init(void) |
| 114 | { |
| 115 | struct pci_mmcfg_region *cfg; |
| 116 | |
| 117 | list_for_each_entry(cfg, &pci_mmcfg_list, list) |
| 118 | if (pci_mmcfg_arch_map(cfg)) { |
| 119 | pci_mmcfg_arch_free(); |
| 120 | return 0; |
| 121 | } |
| 122 | |
| 123 | raw_pci_ext_ops = &pci_mmcfg; |
| 124 | |
| 125 | return 1; |
| 126 | } |
| 127 | |
| 128 | void __init pci_mmcfg_arch_free(void) |
| 129 | { |
| 130 | struct pci_mmcfg_region *cfg; |
| 131 | |
| 132 | list_for_each_entry(cfg, &pci_mmcfg_list, list) |
| 133 | pci_mmcfg_arch_unmap(cfg); |
| 134 | } |
| 135 | |
| 136 | int pci_mmcfg_arch_map(struct pci_mmcfg_region *cfg) |
| 137 | { |
| 138 | cfg->virt = mcfg_ioremap(cfg); |
| 139 | if (!cfg->virt) { |
| 140 | pr_err(PREFIX "can't map MMCONFIG at %pR\n", &cfg->res); |
| 141 | return -ENOMEM; |
| 142 | } |
| 143 | |
| 144 | return 0; |
| 145 | } |
| 146 | |
| 147 | void pci_mmcfg_arch_unmap(struct pci_mmcfg_region *cfg) |
| 148 | { |
| 149 | if (cfg && cfg->virt) { |
| 150 | iounmap(cfg->virt + PCI_MMCFG_BUS_OFFSET(cfg->start_bus)); |
| 151 | cfg->virt = NULL; |
| 152 | } |
| 153 | } |