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
17static 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
26static 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))) {
33err:		*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
56static 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
84static const struct pci_raw_ops pci_mmcfg = {
85	.read =		pci_mmcfg_read,
86	.write =	pci_mmcfg_write,
87};
88
89static 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
104int __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
121void __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