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